[PATCH v5 00/17] riscv: Support vendor extensions and xtheadvector

[PATCH v5 00/17] riscv: Support vendor extensions and xtheadvector

[Charlie Jenkins]

This patch series ended up much larger than expected, please bear with
me! The goal here is to support vendor extensions, starting at probing
the device tree and ending with reporting to userspace.

The main design objective was to allow vendors to operate independently
of each other. This has been achieved by delegating vendor extensions to
a their own files and then accumulating the extensions in
arch/riscv/kernel/vendor_extensions.c.

Each vendor will have their own list of extensions they support.

There is a new hwprobe key RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 that is
used to request which thead vendor extensions are supported on the
current platform. This allows future vendors to allocate hwprobe keys
for their vendor.

On to the xtheadvector specific code. xtheadvector is a custom extension
that is based upon riscv vector version 0.7.1 [1]. All of the vector
routines have been modified to support this alternative vector version
based upon whether xtheadvector was determined to be supported at boot.
I have tested this with an Allwinner Nezha board. I ran into issues
booting the board on 6.9-rc1 so I applied these patches to 6.8. There
are a couple of minor merge conflicts that do arrise when doing that, so
please let me know if you have been able to boot this board with a 6.9
kernel. I used SkiffOS [2] to manage building the image, but upgraded
the U-Boot version to Samuel Holland's more up-to-date version [3] and
changed out the device tree used by U-Boot with the device trees that
are present in upstream linux and this series. Thank you Samuel for all
of the work you did to make this task possible.

To test the integration, I used the riscv vector kselftests. I modified
the test cases to be able to more easily extend them, and then added a
xtheadvector target that works by calling hwprobe and swapping out the
vector asm if needed.

[1] https://github.com/T-head-Semi/thead-extension-spec/blob/95358cb2cca9489361c61d335e03d3134b14133f/xtheadvector.adoc
[2] https://github.com/skiffos/SkiffOS/tree/master/configs/allwinner/nezha
[3] https://github.com/smaeul/u-boot/commit/2e89b706f5c956a70c989cd31665f1429e9a0b48

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
Changes in v5:
- Make all vendors have the same size bitmap
- Extract vendor hwprobe code into helper macro
- Fix bug related to the handling of vendor extensions in the parsing of
  the isa string (Conor)
- Fix bug with the vendor bitmap being incorrectly populated (Evan)
- Add vendor extensions to /proc/cpuinfo
- Link to v4: https://lore.kernel.org/r/20240426-dev-charlie-support_thead_vector_6_9-v4-0-5cf53b5bc492@rivosinc.com

Changes in v4:
- Disable vector immediately if vlenb from the device tree is not
  homogeneous
- Hide vendor extension code behind a hidden config that vendor
  extensions select to eliminate the code when kernel is compiled
  without vendor extensions
- Clear up naming conventions and introduce some defines to make the
  vendor extension code clearer
- Link to v3: https://lore.kernel.org/r/20240420-dev-charlie-support_thead_vector_6_9-v3-0-67cff4271d1d@rivosinc.com

Changes in v3:
- Allow any hardware to support any vendor extension, rather than
  restricting the vendor extensions to the same vendor as the hardware
- Introduce config options to enable/disable a vendor's extensions
- Link to v2: https://lore.kernel.org/r/20240415-dev-charlie-support_thead_vector_6_9-v2-0-c7d68c603268@rivosinc.com

Changes in v2:
- Added commit hash to xtheadvector
- Simplified riscv,isa vector removal fix to not mess with the DT
  riscv,vendorid
- Moved riscv,vendorid parsing into a different patch and cache the
  value to be used by alternative patching
- Reduce riscv,vendorid missing severity to "info"
- Separate vendor extension list to vendor files
- xtheadvector no longer puts v in the elf_hwcap
- Only patch vendor extension if all harts are associated with the same
  vendor. This is the best chance the kernel has for working properly if
  there are multiple vendors.
- Split hwprobe vendor keys out into vendor file
- Add attribution for Heiko's patches
- Link to v1: https://lore.kernel.org/r/20240411-dev-charlie-support_thead_vector_6_9-v1-0-4af9815ec746@rivosinc.com

---
Charlie Jenkins (15):
      dt-bindings: riscv: Add xtheadvector ISA extension description
      riscv: vector: Use vlenb from DT
      riscv: dts: allwinner: Add xtheadvector to the D1/D1s devicetree
      riscv: Extend cpufeature.c to detect vendor extensions
      riscv: Add vendor extensions to /proc/cpuinfo
      riscv: Introduce vendor variants of extension helpers
      riscv: cpufeature: Extract common elements from extension checking
      riscv: Convert xandespmu to use the vendor extension framework
      riscv: csr: Add CSR encodings for VCSR_VXRM/VCSR_VXSAT
      riscv: Add xtheadvector instruction definitions
      riscv: vector: Support xtheadvector save/restore
      riscv: hwprobe: Add thead vendor extension probing
      riscv: hwprobe: Document thead vendor extensions and xtheadvector extension
      selftests: riscv: Fix vector tests
      selftests: riscv: Support xtheadvector in vector tests

Conor Dooley (1):
      dt-bindings: riscv: cpus: add a vlen register length property

Heiko Stuebner (1):
      RISC-V: define the elements of the VCSR vector CSR

 Documentation/arch/riscv/hwprobe.rst               |  10 +
 Documentation/devicetree/bindings/riscv/cpus.yaml  |   6 +
 .../devicetree/bindings/riscv/extensions.yaml      |  10 +
 arch/riscv/Kconfig                                 |   2 +
 arch/riscv/Kconfig.vendor                          |  44 +++
 arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi      |   3 +-
 arch/riscv/errata/andes/errata.c                   |   2 +
 arch/riscv/errata/sifive/errata.c                  |   3 +
 arch/riscv/errata/thead/errata.c                   |   3 +
 arch/riscv/include/asm/cpufeature.h                |  98 ++++---
 arch/riscv/include/asm/csr.h                       |  13 +
 arch/riscv/include/asm/hwcap.h                     |   1 -
 arch/riscv/include/asm/hwprobe.h                   |   4 +-
 arch/riscv/include/asm/switch_to.h                 |   2 +-
 arch/riscv/include/asm/vector.h                    | 247 +++++++++++++----
 arch/riscv/include/asm/vendor_extensions.h         | 103 +++++++
 arch/riscv/include/asm/vendor_extensions/andes.h   |  19 ++
 arch/riscv/include/asm/vendor_extensions/thead.h   |  42 +++
 .../include/asm/vendor_extensions/thead_hwprobe.h  |  18 ++
 .../include/asm/vendor_extensions/vendor_hwprobe.h |  34 +++
 arch/riscv/include/uapi/asm/hwprobe.h              |   3 +-
 arch/riscv/include/uapi/asm/vendor/thead.h         |   3 +
 arch/riscv/kernel/Makefile                         |   2 +
 arch/riscv/kernel/cpu.c                            |  35 ++-
 arch/riscv/kernel/cpufeature.c                     | 171 +++++++++---
 arch/riscv/kernel/kernel_mode_vector.c             |   8 +-
 arch/riscv/kernel/process.c                        |   4 +-
 arch/riscv/kernel/signal.c                         |   6 +-
 arch/riscv/kernel/sys_hwprobe.c                    |   5 +
 arch/riscv/kernel/vector.c                         |  25 +-
 arch/riscv/kernel/vendor_extensions.c              |  66 +++++
 arch/riscv/kernel/vendor_extensions/Makefile       |   5 +
 arch/riscv/kernel/vendor_extensions/andes.c        |  18 ++
 arch/riscv/kernel/vendor_extensions/thead.c        |  18 ++
 .../riscv/kernel/vendor_extensions/thead_hwprobe.c |  19 ++
 drivers/perf/riscv_pmu_sbi.c                       |   9 +-
 tools/testing/selftests/riscv/vector/.gitignore    |   3 +-
 tools/testing/selftests/riscv/vector/Makefile      |  17 +-
 .../selftests/riscv/vector/v_exec_initval_nolibc.c |  93 +++++++
 tools/testing/selftests/riscv/vector/v_helpers.c   |  67 +++++
 tools/testing/selftests/riscv/vector/v_helpers.h   |   7 +
 tools/testing/selftests/riscv/vector/v_initval.c   |  22 ++
 .../selftests/riscv/vector/v_initval_nolibc.c      |  68 -----
 .../selftests/riscv/vector/vstate_exec_nolibc.c    |  20 +-
 .../testing/selftests/riscv/vector/vstate_prctl.c  | 295 ++++++++++++---------
 45 files changed, 1312 insertions(+), 341 deletions(-)
---
base-commit: 4cece764965020c22cff7665b18a012006359095
change-id: 20240411-dev-charlie-support_thead_vector_6_9-1591fc2a431d
-- 
- Charlie

[PATCH v5 01/17] dt-bindings: riscv: Add xtheadvector ISA extension description

[Charlie Jenkins]

The xtheadvector ISA extension is described on the T-Head extension spec
Github page [1] at commit 95358cb2cca9.

Link: https://github.com/T-head-Semi/thead-extension-spec/blob/95358cb2cca9489361c61d335e03d3134b14133f/xtheadvector.adoc [1]

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
 Documentation/devicetree/bindings/riscv/extensions.yaml | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index 468c646247aa..99d2a9e8c52d 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -477,6 +477,10 @@ properties:
             latency, as ratified in commit 56ed795 ("Update
             riscv-crypto-spec-vector.adoc") of riscv-crypto.
 
+        # vendor extensions, each extension sorted alphanumerically under the
+        # vendor they belong to. Vendors are sorted alphanumerically as well.
+
+        # Andes
         - const: xandespmu
           description:
             The Andes Technology performance monitor extension for counter overflow
@@ -484,5 +488,11 @@ properties:
             Registers in the AX45MP datasheet.
             https://www.andestech.com/wp-content/uploads/AX45MP-1C-Rev.-5.0.0-Datasheet.pdf
 
+        # T-HEAD
+        - const: xtheadvector
+          description:
+            The T-HEAD specific 0.7.1 vector implementation as written in
+            https://github.com/T-head-Semi/thead-extension-spec/blob/95358cb2cca9489361c61d335e03d3134b14133f/xtheadvector.adoc.
+
 additionalProperties: true
 ...

-- 
2.44.0

[PATCH v5 02/17] dt-bindings: riscv: cpus: add a vlen register length property

[Charlie Jenkins]

From: Conor Dooley <conor.dooley@microchip.com>

Add a property analogous to the vlenb CSR so that software can detect
the vector length of each CPU prior to it being brought online.
Currently software has to assume that the vector length read from the
boot CPU applies to all possible CPUs. On T-Head CPUs implementing
pre-ratification vector, reading the th.vlenb CSR may produce an illegal
instruction trap, so this property is required on such systems.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 Documentation/devicetree/bindings/riscv/cpus.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml
index d87dd50f1a4b..edcb6a7d9319 100644
--- a/Documentation/devicetree/bindings/riscv/cpus.yaml
+++ b/Documentation/devicetree/bindings/riscv/cpus.yaml
@@ -94,6 +94,12 @@ properties:
     description:
       The blocksize in bytes for the Zicboz cache operations.
 
+  riscv,vlenb:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      VLEN/8, the vector register length in bytes. This property is required in
+      systems where the vector register length is not identical on all harts.
+
   # RISC-V has multiple properties for cache op block sizes as the sizes
   # differ between individual CBO extensions
   cache-op-block-size: false

-- 
2.44.0

[PATCH v5 03/17] riscv: vector: Use vlenb from DT

[Charlie Jenkins]

If vlenb is provided in the device tree, prefer that over reading the
vlenb csr.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/include/asm/cpufeature.h |  2 ++
 arch/riscv/kernel/cpufeature.c      | 43 +++++++++++++++++++++++++++++++++++++
 arch/riscv/kernel/vector.c          | 12 ++++++++++-
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index 347805446151..0c4f08577015 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -31,6 +31,8 @@ DECLARE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);
 /* Per-cpu ISA extensions. */
 extern struct riscv_isainfo hart_isa[NR_CPUS];
 
+extern u32 riscv_vlenb_of;
+
 void riscv_user_isa_enable(void);
 
 #if defined(CONFIG_RISCV_MISALIGNED)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 3ed2359eae35..12c79db0b0bb 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -35,6 +35,8 @@ static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
 /* Per-cpu ISA extensions. */
 struct riscv_isainfo hart_isa[NR_CPUS];
 
+u32 riscv_vlenb_of;
+
 /**
  * riscv_isa_extension_base() - Get base extension word
  *
@@ -648,6 +650,42 @@ static int __init riscv_isa_fallback_setup(char *__unused)
 early_param("riscv_isa_fallback", riscv_isa_fallback_setup);
 #endif
 
+static int has_riscv_homogeneous_vlenb(void)
+{
+	int cpu;
+	u32 prev_vlenb = 0;
+	u32 vlenb;
+
+	for_each_possible_cpu(cpu) {
+		struct device_node *cpu_node;
+
+		cpu_node = of_cpu_device_node_get(cpu);
+		if (!cpu_node) {
+			pr_warn("Unable to find cpu node\n");
+			return -ENOENT;
+		}
+
+		if (of_property_read_u32(cpu_node, "riscv,vlenb", &vlenb)) {
+			of_node_put(cpu_node);
+
+			if (prev_vlenb)
+				return -ENOENT;
+			continue;
+		}
+
+		if (prev_vlenb && vlenb != prev_vlenb) {
+			of_node_put(cpu_node);
+			return -ENOENT;
+		}
+
+		prev_vlenb = vlenb;
+		of_node_put(cpu_node);
+	}
+
+	riscv_vlenb_of = vlenb;
+	return 0;
+}
+
 void __init riscv_fill_hwcap(void)
 {
 	char print_str[NUM_ALPHA_EXTS + 1];
@@ -671,6 +709,11 @@ void __init riscv_fill_hwcap(void)
 			pr_info("Falling back to deprecated \"riscv,isa\"\n");
 			riscv_fill_hwcap_from_isa_string(isa2hwcap);
 		}
+
+		if (elf_hwcap & COMPAT_HWCAP_ISA_V && has_riscv_homogeneous_vlenb() < 0) {
+			pr_warn("Unsupported heterogeneous vlen detected, vector extension disabled.\n");
+			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
+		}
 	}
 
 	/*
diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
index 6727d1d3b8f2..e04586cdb7f0 100644
--- a/arch/riscv/kernel/vector.c
+++ b/arch/riscv/kernel/vector.c
@@ -33,7 +33,17 @@ int riscv_v_setup_vsize(void)
 {
 	unsigned long this_vsize;
 
-	/* There are 32 vector registers with vlenb length. */
+	/*
+	 * There are 32 vector registers with vlenb length.
+	 *
+	 * If the riscv,vlenb property was provided by the firmware, use that
+	 * instead of probing the CSRs.
+	 */
+	if (riscv_vlenb_of) {
+		this_vsize = riscv_vlenb_of * 32;
+		return 0;
+	}
+
 	riscv_v_enable();
 	this_vsize = csr_read(CSR_VLENB) * 32;
 	riscv_v_disable();

-- 
2.44.0

[PATCH v5 04/17] riscv: dts: allwinner: Add xtheadvector to the D1/D1s devicetree

[Charlie Jenkins]

The D1/D1s SoCs support xtheadvector so it can be included in the
devicetree. Also include vlenb for the cpu.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi b/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi
index 64c3c2e6cbe0..50c9f4ec8a7f 100644
--- a/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi
+++ b/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi
@@ -27,7 +27,8 @@ cpu0: cpu@0 {
 			riscv,isa = "rv64imafdc";
 			riscv,isa-base = "rv64i";
 			riscv,isa-extensions = "i", "m", "a", "f", "d", "c", "zicntr", "zicsr",
-					       "zifencei", "zihpm";
+					       "zifencei", "zihpm", "xtheadvector";
+			riscv,vlenb = <128>;
 			#cooling-cells = <2>;
 
 			cpu0_intc: interrupt-controller {

-- 
2.44.0

[PATCH v5 05/17] riscv: Extend cpufeature.c to detect vendor extensions

[Charlie Jenkins]

Separate vendor extensions out into one struct per vendor
instead of adding vendor extensions onto riscv_isa_ext.

Add a hidden config RISCV_ISA_VENDOR_EXT to conditionally include this
code.

The xtheadvector vendor extension is added using these changes.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/Kconfig                               |  2 +
 arch/riscv/Kconfig.vendor                        | 19 +++++
 arch/riscv/include/asm/cpufeature.h              | 18 +++++
 arch/riscv/include/asm/vendor_extensions.h       | 34 +++++++++
 arch/riscv/include/asm/vendor_extensions/thead.h | 16 ++++
 arch/riscv/kernel/Makefile                       |  2 +
 arch/riscv/kernel/cpufeature.c                   | 93 +++++++++++++++++++-----
 arch/riscv/kernel/vendor_extensions.c            | 18 +++++
 arch/riscv/kernel/vendor_extensions/Makefile     |  3 +
 arch/riscv/kernel/vendor_extensions/thead.c      | 18 +++++
 10 files changed, 203 insertions(+), 20 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index be09c8836d56..fec86fba3acd 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -759,6 +759,8 @@ config RISCV_EFFICIENT_UNALIGNED_ACCESS
 
 endchoice
 
+source "arch/riscv/Kconfig.vendor"
+
 endmenu # "Platform type"
 
 menu "Kernel features"
diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor
new file mode 100644
index 000000000000..85ac30496b0e
--- /dev/null
+++ b/arch/riscv/Kconfig.vendor
@@ -0,0 +1,19 @@
+menu "Vendor extensions"
+
+config RISCV_ISA_VENDOR_EXT
+	bool
+
+menu "T-Head"
+config RISCV_ISA_VENDOR_EXT_THEAD
+	bool "T-Head vendor extension support"
+	select RISCV_ISA_VENDOR_EXT
+	default y
+	help
+	  Say N here to disable detection of and support for all T-Head vendor
+	  extensions. Without this option enabled, T-Head vendor extensions will
+	  not be detected at boot and their presence not reported to userspace.
+
+	  If you don't know what to do here, say Y.
+endmenu
+
+endmenu
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index 0c4f08577015..fedd479ccfd1 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -35,6 +35,24 @@ extern u32 riscv_vlenb_of;
 
 void riscv_user_isa_enable(void);
 
+#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {	\
+	.name = #_name,								\
+	.property = #_name,							\
+	.id = _id,								\
+	.subset_ext_ids = _subset_exts,						\
+	.subset_ext_size = _subset_exts_size					\
+}
+
+#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
+
+/* Used to declare pure "lasso" extension (Zk for instance) */
+#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
+	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
+
+/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
+#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
+	_RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
+
 #if defined(CONFIG_RISCV_MISALIGNED)
 bool check_unaligned_access_emulated_all_cpus(void);
 void unaligned_emulation_finish(void);
diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
new file mode 100644
index 000000000000..bf4dac66e6e6
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2024 Rivos, Inc
+ */
+
+#ifndef _ASM_VENDOR_EXTENSIONS_H
+#define _ASM_VENDOR_EXTENSIONS_H
+
+#include <asm/cpufeature.h>
+
+#include <linux/array_size.h>
+#include <linux/types.h>
+
+/*
+ * The extension keys of each vendor must be strictly less than this value.
+ */
+#define RISCV_ISA_VENDOR_EXT_MAX 32
+
+struct riscv_isavendorinfo {
+	DECLARE_BITMAP(isa, RISCV_ISA_VENDOR_EXT_MAX);
+};
+
+struct riscv_isa_vendor_ext_data_list {
+	const size_t ext_data_count;
+	const struct riscv_isa_ext_data *ext_data;
+	struct riscv_isavendorinfo per_hart_isa_bitmap[NR_CPUS];
+	struct riscv_isavendorinfo all_harts_isa_bitmap;
+};
+
+extern struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[];
+
+extern const size_t riscv_isa_vendor_ext_list_size;
+
+#endif /* _ASM_VENDOR_EXTENSIONS_H */
diff --git a/arch/riscv/include/asm/vendor_extensions/thead.h b/arch/riscv/include/asm/vendor_extensions/thead.h
new file mode 100644
index 000000000000..48421d1553ad
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions/thead.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
+#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
+
+#include <asm/vendor_extensions.h>
+
+#include <linux/types.h>
+
+/*
+ * Extension keys must be strictly less than RISCV_ISA_VENDOR_EXT_MAX.
+ */
+#define RISCV_ISA_VENDOR_EXT_XTHEADVECTOR		0
+
+extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead;
+
+#endif
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 81d94a8ee10f..53361c50fb46 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -58,6 +58,8 @@ obj-y	+= riscv_ksyms.o
 obj-y	+= stacktrace.o
 obj-y	+= cacheinfo.o
 obj-y	+= patch.o
+obj-y	+= vendor_extensions.o
+obj-y	+= vendor_extensions/
 obj-y	+= probes/
 obj-y	+= tests/
 obj-$(CONFIG_MMU) += vdso.o vdso/
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 12c79db0b0bb..cc9ec393c8f6 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -24,6 +24,7 @@
 #include <asm/processor.h>
 #include <asm/sbi.h>
 #include <asm/vector.h>
+#include <asm/vendor_extensions.h>
 
 #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
 
@@ -102,24 +103,6 @@ static bool riscv_isa_extension_check(int id)
 	return true;
 }
 
-#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {	\
-	.name = #_name,								\
-	.property = #_name,							\
-	.id = _id,								\
-	.subset_ext_ids = _subset_exts,						\
-	.subset_ext_size = _subset_exts_size					\
-}
-
-#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
-
-/* Used to declare pure "lasso" extension (Zk for instance) */
-#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
-	_RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
-
-/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
-#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
-	_RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
-
 static const unsigned int riscv_zk_bundled_exts[] = {
 	RISCV_ISA_EXT_ZBKB,
 	RISCV_ISA_EXT_ZBKC,
@@ -353,6 +336,21 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
 		bool ext_long = false, ext_err = false;
 
 		switch (*ext) {
+		case 'x':
+		case 'X':
+			if (acpi_disabled)
+				pr_warn_once("Vendor extensions are ignored in riscv,isa. Use riscv,isa-extensions instead.");
+			/*
+			 * To skip an extension, we find its end.
+			 * As multi-letter extensions must be split from other multi-letter
+			 * extensions with an "_", the end of a multi-letter extension will
+			 * either be the null character or the "_" at the start of the next
+			 * multi-letter extension.
+			 */
+			for (; *isa && *isa != '_'; ++isa)
+				;
+			ext_err = true;
+			break;
 		case 's':
 			/*
 			 * Workaround for invalid single-letter 's' & 'u' (QEMU).
@@ -368,8 +366,6 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
 			}
 			fallthrough;
 		case 'S':
-		case 'x':
-		case 'X':
 		case 'z':
 		case 'Z':
 			/*
@@ -572,6 +568,59 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
 		acpi_put_table((struct acpi_table_header *)rhct);
 }
 
+static void __init riscv_fill_cpu_vendor_ext(struct device_node *cpu_node, int cpu)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
+		return;
+
+	for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
+		struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
+
+		for (int j = 0; j < ext_list->ext_data_count; j++) {
+			const struct riscv_isa_ext_data ext = ext_list->ext_data[j];
+			struct riscv_isavendorinfo *isavendorinfo = &ext_list->per_hart_isa_bitmap[cpu];
+
+			if (of_property_match_string(cpu_node, "riscv,isa-extensions",
+						     ext.property) < 0)
+				continue;
+
+			/*
+			 * Assume that subset extensions are all members of the
+			 * same vendor.
+			 */
+			if (ext.subset_ext_size)
+				for (int k = 0; k < ext.subset_ext_size; k++)
+					set_bit(ext.subset_ext_ids[k], isavendorinfo->isa);
+
+			set_bit(ext.id, isavendorinfo->isa);
+		}
+	}
+}
+
+static void __init riscv_fill_vendor_ext_list(int cpu)
+{
+	bool first = true;
+
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
+		return;
+
+	for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
+		struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
+
+		if (first) {
+			bitmap_copy(ext_list->all_harts_isa_bitmap.isa,
+				    ext_list->per_hart_isa_bitmap[cpu].isa,
+				    RISCV_ISA_VENDOR_EXT_MAX);
+			first = false;
+		} else {
+			bitmap_and(ext_list->all_harts_isa_bitmap.isa,
+				   ext_list->all_harts_isa_bitmap.isa,
+				   ext_list->per_hart_isa_bitmap[cpu].isa,
+				   RISCV_ISA_VENDOR_EXT_MAX);
+		}
+	}
+}
+
 static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
 {
 	unsigned int cpu;
@@ -615,6 +664,8 @@ static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
 			}
 		}
 
+		riscv_fill_cpu_vendor_ext(cpu_node, cpu);
+
 		of_node_put(cpu_node);
 
 		/*
@@ -630,6 +681,8 @@ static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
 			bitmap_copy(riscv_isa, isainfo->isa, RISCV_ISA_EXT_MAX);
 		else
 			bitmap_and(riscv_isa, riscv_isa, isainfo->isa, RISCV_ISA_EXT_MAX);
+
+		riscv_fill_vendor_ext_list(cpu);
 	}
 
 	if (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))
diff --git a/arch/riscv/kernel/vendor_extensions.c b/arch/riscv/kernel/vendor_extensions.c
new file mode 100644
index 000000000000..03ba7949a07f
--- /dev/null
+++ b/arch/riscv/kernel/vendor_extensions.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2024 Rivos, Inc
+ */
+
+#include <asm/vendor_extensions.h>
+#include <asm/vendor_extensions/thead.h>
+
+#include <linux/array_size.h>
+#include <linux/types.h>
+
+struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[] = {
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
+	&riscv_isa_vendor_ext_list_thead,
+#endif
+};
+
+const size_t riscv_isa_vendor_ext_list_size = ARRAY_SIZE(riscv_isa_vendor_ext_list);
diff --git a/arch/riscv/kernel/vendor_extensions/Makefile b/arch/riscv/kernel/vendor_extensions/Makefile
new file mode 100644
index 000000000000..3383066baaab
--- /dev/null
+++ b/arch/riscv/kernel/vendor_extensions/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD)	+= thead.o
diff --git a/arch/riscv/kernel/vendor_extensions/thead.c b/arch/riscv/kernel/vendor_extensions/thead.c
new file mode 100644
index 000000000000..0934a2086473
--- /dev/null
+++ b/arch/riscv/kernel/vendor_extensions/thead.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm/cpufeature.h>
+#include <asm/vendor_extensions.h>
+#include <asm/vendor_extensions/thead.h>
+
+#include <linux/array_size.h>
+#include <linux/types.h>
+
+/* All T-Head vendor extensions supported in Linux */
+const struct riscv_isa_ext_data riscv_isa_vendor_ext_thead[] = {
+	__RISCV_ISA_EXT_DATA(xtheadvector, RISCV_ISA_VENDOR_EXT_XTHEADVECTOR),
+};
+
+struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead = {
+	.ext_data_count = ARRAY_SIZE(riscv_isa_vendor_ext_thead),
+	.ext_data = riscv_isa_vendor_ext_thead,
+};

-- 
2.44.0

[PATCH v5 06/17] riscv: Add vendor extensions to /proc/cpuinfo

[Charlie Jenkins]

All of the supported vendor extensions that have been listed in
riscv_isa_vendor_ext_list can be exported through /proc/cpuinfo.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/kernel/cpu.c | 35 ++++++++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index d11d6320fb0d..2a7924dd809b 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -16,6 +16,7 @@
 #include <asm/sbi.h>
 #include <asm/smp.h>
 #include <asm/pgtable.h>
+#include <asm/vendor_extensions.h>
 
 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {
@@ -203,7 +204,33 @@ arch_initcall(riscv_cpuinfo_init);
 
 #ifdef CONFIG_PROC_FS
 
-static void print_isa(struct seq_file *f, const unsigned long *isa_bitmap)
+#define ALL_CPUS -1
+
+static void print_vendor_isa(struct seq_file *f, int cpu)
+{
+	struct riscv_isavendorinfo *vendor_bitmap;
+	struct riscv_isa_vendor_ext_data_list *ext_list;
+	const struct riscv_isa_ext_data *ext_data;
+
+	for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
+		ext_list = riscv_isa_vendor_ext_list[i];
+		ext_data = riscv_isa_vendor_ext_list[i]->ext_data;
+
+		if (cpu == ALL_CPUS)
+			vendor_bitmap = &ext_list->all_harts_isa_bitmap;
+		else
+			vendor_bitmap = &ext_list->per_hart_isa_bitmap[cpu];
+
+		for (int j = 0; j < ext_list->ext_data_count; j++) {
+			if (!__riscv_isa_extension_available(vendor_bitmap->isa, ext_data[j].id))
+				continue;
+
+			seq_printf(f, "_%s", ext_data[j].name);
+		}
+	}
+}
+
+static void print_isa(struct seq_file *f, const unsigned long *isa_bitmap, int cpu)
 {
 
 	if (IS_ENABLED(CONFIG_32BIT))
@@ -222,6 +249,8 @@ static void print_isa(struct seq_file *f, const unsigned long *isa_bitmap)
 		seq_printf(f, "%s", riscv_isa_ext[i].name);
 	}
 
+	print_vendor_isa(f, cpu);
+
 	seq_puts(f, "\n");
 }
 
@@ -284,7 +313,7 @@ static int c_show(struct seq_file *m, void *v)
 	 * line.
 	 */
 	seq_puts(m, "isa\t\t: ");
-	print_isa(m, NULL);
+	print_isa(m, NULL, ALL_CPUS);
 	print_mmu(m);
 
 	if (acpi_disabled) {
@@ -306,7 +335,7 @@ static int c_show(struct seq_file *m, void *v)
 	 * additional extensions not present across all harts.
 	 */
 	seq_puts(m, "hart isa\t: ");
-	print_isa(m, hart_isa[cpu_id].isa);
+	print_isa(m, hart_isa[cpu_id].isa, cpu_id);
 	seq_puts(m, "\n");
 
 	return 0;

-- 
2.44.0

[PATCH v5 07/17] riscv: Introduce vendor variants of extension helpers

[Charlie Jenkins]

Vendor extensions are maintained in per-vendor structs (separate from
standard extensions which live in riscv_isa). Create vendor variants for
the existing extension helpers to interface with the riscv_isa_vendor
bitmaps.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/errata/sifive/errata.c          |  3 +
 arch/riscv/errata/thead/errata.c           |  3 +
 arch/riscv/include/asm/vendor_extensions.h | 97 ++++++++++++++++++++++++++++++
 arch/riscv/kernel/cpufeature.c             | 32 +++++++---
 arch/riscv/kernel/vendor_extensions.c      | 40 ++++++++++++
 5 files changed, 167 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c
index 3d9a32d791f7..b68b023115c2 100644
--- a/arch/riscv/errata/sifive/errata.c
+++ b/arch/riscv/errata/sifive/errata.c
@@ -12,6 +12,7 @@
 #include <asm/alternative.h>
 #include <asm/vendorid_list.h>
 #include <asm/errata_list.h>
+#include <asm/vendor_extensions.h>
 
 struct errata_info_t {
 	char name[32];
@@ -91,6 +92,8 @@ void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
 	u32 cpu_apply_errata = 0;
 	u32 tmp;
 
+	BUILD_BUG_ON(ERRATA_SIFIVE_NUMBER >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+
 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
 		return;
 
diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
index b1c410bbc1ae..6d5d7f8eebbc 100644
--- a/arch/riscv/errata/thead/errata.c
+++ b/arch/riscv/errata/thead/errata.c
@@ -18,6 +18,7 @@
 #include <asm/io.h>
 #include <asm/patch.h>
 #include <asm/vendorid_list.h>
+#include <asm/vendor_extensions.h>
 
 static bool errata_probe_pbmt(unsigned int stage,
 			      unsigned long arch_id, unsigned long impid)
@@ -160,6 +161,8 @@ void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
 	u32 tmp;
 	void *oldptr, *altptr;
 
+	BUILD_BUG_ON(ERRATA_THEAD_NUMBER >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+
 	for (alt = begin; alt < end; alt++) {
 		if (alt->vendor_id != THEAD_VENDOR_ID)
 			continue;
diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
index bf4dac66e6e6..a6959836f895 100644
--- a/arch/riscv/include/asm/vendor_extensions.h
+++ b/arch/riscv/include/asm/vendor_extensions.h
@@ -31,4 +31,101 @@ extern struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[];
 
 extern const size_t riscv_isa_vendor_ext_list_size;
 
+/*
+ * The alternatives need some way of distinguishing between vendor extensions
+ * and errata. Incrementing all of the vendor extension keys so they are at
+ * least 0x8000 accomplishes that.
+ */
+#define RISCV_VENDOR_EXT_ALTERNATIVES_BASE	0x8000
+
+#define VENDOR_EXT_ALL_CPUS			-1
+
+bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsigned int bit);
+#define riscv_cpu_isa_vendor_extension_available(cpu, vendor, ext)	\
+	__riscv_isa_vendor_extension_available(cpu, vendor, RISCV_ISA_VENDOR_EXT_##ext)
+#define riscv_isa_vendor_extension_available(vendor, ext)	\
+	__riscv_isa_vendor_extension_available(VENDOR_EXT_ALL_CPUS, vendor, \
+					       RISCV_ISA_VENDOR_EXT_##ext)
+
+static __always_inline bool __riscv_has_extension_likely(const unsigned long vendor,
+							 const unsigned long ext)
+{
+	asm goto(ALTERNATIVE("j	%l[l_no]", "nop", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_no);
+
+	return true;
+l_no:
+	return false;
+}
+
+static __always_inline bool __riscv_has_extension_unlikely(const unsigned long vendor,
+							   const unsigned long ext)
+{
+	asm goto(ALTERNATIVE("nop", "j	%l[l_yes]", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_yes);
+
+	return false;
+l_yes:
+	return true;
+}
+
+static __always_inline bool riscv_has_vendor_extension_likely(const unsigned long vendor,
+							      const unsigned long ext)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
+		return false;
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_likely(vendor,
+						    ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+
+	return __riscv_isa_vendor_extension_available(VENDOR_EXT_ALL_CPUS, vendor, ext);
+}
+
+static __always_inline bool riscv_has_vendor_extension_unlikely(const unsigned long vendor,
+								const unsigned long ext)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
+		return false;
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_unlikely(vendor,
+						      ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+
+	return __riscv_isa_vendor_extension_available(VENDOR_EXT_ALL_CPUS, vendor, ext);
+}
+
+static __always_inline bool riscv_cpu_has_vendor_extension_likely(const unsigned long vendor,
+								  int cpu, const unsigned long ext)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
+		return false;
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_likely(vendor, ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE))
+		return true;
+
+	return __riscv_isa_vendor_extension_available(cpu, vendor, ext);
+}
+
+static __always_inline bool riscv_cpu_has_vendor_extension_unlikely(const unsigned long vendor,
+								    int cpu,
+								    const unsigned long ext)
+{
+	if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
+		return false;
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_unlikely(vendor, ext + RISCV_VENDOR_EXT_ALTERNATIVES_BASE))
+		return true;
+
+	return __riscv_isa_vendor_extension_available(cpu, vendor, ext);
+}
+
 #endif /* _ASM_VENDOR_EXTENSIONS_H */
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index cc9ec393c8f6..b1f35564a1e0 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -860,25 +860,41 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
 {
 	struct alt_entry *alt;
 	void *oldptr, *altptr;
-	u16 id, value;
+	u16 id, value, vendor;
 
 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
 		return;
 
 	for (alt = begin; alt < end; alt++) {
-		if (alt->vendor_id != 0)
-			continue;
-
 		id = PATCH_ID_CPUFEATURE_ID(alt->patch_id);
+		vendor = PATCH_ID_CPUFEATURE_ID(alt->vendor_id);
 
-		if (id >= RISCV_ISA_EXT_MAX) {
+		/*
+		 * Any alternative with a patch_id that is less than
+		 * RISCV_ISA_EXT_MAX is interpreted as a standard extension.
+		 *
+		 * Any alternative with patch_id that is greater than or equal
+		 * to RISCV_VENDOR_EXT_ALTERNATIVES_BASE is interpreted as a
+		 * vendor extension.
+		 */
+		if (id < RISCV_ISA_EXT_MAX) {
+			/*
+			 * This patch should be treated as errata so skip
+			 * processing here.
+			 */
+			if (alt->vendor_id != 0)
+				continue;
+
+			if (!__riscv_isa_extension_available(NULL, id))
+				continue;
+		} else if (id >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE) {
+			if (!__riscv_isa_vendor_extension_available(VENDOR_EXT_ALL_CPUS, vendor, id))
+				continue;
+		} else {
 			WARN(1, "This extension id:%d is not in ISA extension list", id);
 			continue;
 		}
 
-		if (!__riscv_isa_extension_available(NULL, id))
-			continue;
-
 		value = PATCH_ID_CPUFEATURE_VALUE(alt->patch_id);
 		if (!riscv_cpufeature_patch_check(id, value))
 			continue;
diff --git a/arch/riscv/kernel/vendor_extensions.c b/arch/riscv/kernel/vendor_extensions.c
index 03ba7949a07f..e4ef574b7d08 100644
--- a/arch/riscv/kernel/vendor_extensions.c
+++ b/arch/riscv/kernel/vendor_extensions.c
@@ -3,6 +3,7 @@
  * Copyright 2024 Rivos, Inc
  */
 
+#include <asm/vendorid_list.h>
 #include <asm/vendor_extensions.h>
 #include <asm/vendor_extensions/thead.h>
 
@@ -16,3 +17,42 @@ struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[] = {
 };
 
 const size_t riscv_isa_vendor_ext_list_size = ARRAY_SIZE(riscv_isa_vendor_ext_list);
+
+/**
+ * __riscv_isa_vendor_extension_available() - Check whether given vendor
+ * extension is available or not.
+ *
+ * @cpu: check if extension is available on this cpu
+ * @vendor: vendor that the extension is a member of
+ * @bit: bit position of the desired extension
+ * Return: true or false
+ *
+ * NOTE: When cpu is -1, will check if extension is available on all cpus
+ */
+bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsigned int bit)
+{
+	unsigned long *bmap;
+	struct riscv_isainfo *cpu_bmap;
+	size_t bmap_size;
+
+	switch (vendor) {
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
+	case THEAD_VENDOR_ID:
+		bmap = riscv_isa_vendor_ext_list_thead.vendor_bitmap;
+		cpu_bmap = riscv_isa_vendor_ext_list_thead.per_hart_vendor_bitmap;
+		bmap_size = riscv_isa_vendor_ext_list_thead.bitmap_size;
+		break;
+#endif
+	default:
+		return false;
+	}
+
+	if (cpu != -1)
+		bmap = cpu_bmap[cpu].isa;
+
+	if (bit >= bmap_size)
+		return false;
+
+	return test_bit(bit, bmap) ? true : false;
+}
+EXPORT_SYMBOL_GPL(__riscv_isa_vendor_extension_available);

-- 
2.44.0

[PATCH v5 08/17] riscv: cpufeature: Extract common elements from extension checking

[Charlie Jenkins]

The __riscv_has_extension_likely() and __riscv_has_extension_unlikely()
functions from the vendor_extensions.h can be used to simplify the
standard extension checking code as well. Migrate those functions to
cpufeature.h and reorganize the code in the file to use the functions.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/include/asm/cpufeature.h        | 78 +++++++++++++++++-------------
 arch/riscv/include/asm/vendor_extensions.h | 28 -----------
 arch/riscv/kernel/vendor_extensions.c      | 16 +++---
 3 files changed, 51 insertions(+), 71 deletions(-)

diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index fedd479ccfd1..88723ac2d26e 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -98,59 +98,66 @@ extern bool riscv_isa_fallback;
 
 unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
 
+#define STANDARD_EXT		0
+
 bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned int bit);
 #define riscv_isa_extension_available(isa_bitmap, ext)	\
 	__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
 
-static __always_inline bool
-riscv_has_extension_likely(const unsigned long ext)
+static __always_inline bool __riscv_has_extension_likely(const unsigned long vendor,
+							 const unsigned long ext)
 {
-	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
-			   "ext must be < RISCV_ISA_EXT_MAX");
-
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE)) {
-		asm goto(
-		ALTERNATIVE("j	%l[l_no]", "nop", 0, %[ext], 1)
-		:
-		: [ext] "i" (ext)
-		:
-		: l_no);
-	} else {
-		if (!__riscv_isa_extension_available(NULL, ext))
-			goto l_no;
-	}
+	asm goto(ALTERNATIVE("j	%l[l_no]", "nop", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_no);
 
 	return true;
 l_no:
 	return false;
 }
 
-static __always_inline bool
-riscv_has_extension_unlikely(const unsigned long ext)
+static __always_inline bool __riscv_has_extension_unlikely(const unsigned long vendor,
+							   const unsigned long ext)
 {
-	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
-			   "ext must be < RISCV_ISA_EXT_MAX");
-
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE)) {
-		asm goto(
-		ALTERNATIVE("nop", "j	%l[l_yes]", 0, %[ext], 1)
-		:
-		: [ext] "i" (ext)
-		:
-		: l_yes);
-	} else {
-		if (__riscv_isa_extension_available(NULL, ext))
-			goto l_yes;
-	}
+	asm goto(ALTERNATIVE("nop", "j	%l[l_yes]", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_yes);
 
 	return false;
 l_yes:
 	return true;
 }
 
+static __always_inline bool riscv_has_extension_unlikely(const unsigned long ext)
+{
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX, "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_unlikely(STANDARD_EXT, ext);
+
+	return __riscv_isa_extension_available(NULL, ext);
+}
+
+static __always_inline bool riscv_has_extension_likely(const unsigned long ext)
+{
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX, "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE))
+		return __riscv_has_extension_likely(STANDARD_EXT, ext);
+
+	return __riscv_isa_extension_available(NULL, ext);
+}
+
 static __always_inline bool riscv_cpu_has_extension_likely(int cpu, const unsigned long ext)
 {
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_likely(ext))
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX, "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_likely(STANDARD_EXT, ext))
 		return true;
 
 	return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
@@ -158,7 +165,10 @@ static __always_inline bool riscv_cpu_has_extension_likely(int cpu, const unsign
 
 static __always_inline bool riscv_cpu_has_extension_unlikely(int cpu, const unsigned long ext)
 {
-	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_unlikely(ext))
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX, "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) &&
+	    __riscv_has_extension_unlikely(STANDARD_EXT, ext))
 		return true;
 
 	return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
index a6959836f895..d21e411d7338 100644
--- a/arch/riscv/include/asm/vendor_extensions.h
+++ b/arch/riscv/include/asm/vendor_extensions.h
@@ -47,34 +47,6 @@ bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsig
 	__riscv_isa_vendor_extension_available(VENDOR_EXT_ALL_CPUS, vendor, \
 					       RISCV_ISA_VENDOR_EXT_##ext)
 
-static __always_inline bool __riscv_has_extension_likely(const unsigned long vendor,
-							 const unsigned long ext)
-{
-	asm goto(ALTERNATIVE("j	%l[l_no]", "nop", %[vendor], %[ext], 1)
-	:
-	: [vendor] "i" (vendor), [ext] "i" (ext)
-	:
-	: l_no);
-
-	return true;
-l_no:
-	return false;
-}
-
-static __always_inline bool __riscv_has_extension_unlikely(const unsigned long vendor,
-							   const unsigned long ext)
-{
-	asm goto(ALTERNATIVE("nop", "j	%l[l_yes]", %[vendor], %[ext], 1)
-	:
-	: [vendor] "i" (vendor), [ext] "i" (ext)
-	:
-	: l_yes);
-
-	return false;
-l_yes:
-	return true;
-}
-
 static __always_inline bool riscv_has_vendor_extension_likely(const unsigned long vendor,
 							      const unsigned long ext)
 {
diff --git a/arch/riscv/kernel/vendor_extensions.c b/arch/riscv/kernel/vendor_extensions.c
index e4ef574b7d08..7910890c17de 100644
--- a/arch/riscv/kernel/vendor_extensions.c
+++ b/arch/riscv/kernel/vendor_extensions.c
@@ -31,16 +31,14 @@ const size_t riscv_isa_vendor_ext_list_size = ARRAY_SIZE(riscv_isa_vendor_ext_li
  */
 bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsigned int bit)
 {
-	unsigned long *bmap;
-	struct riscv_isainfo *cpu_bmap;
-	size_t bmap_size;
+	struct riscv_isavendorinfo *bmap;
+	struct riscv_isavendorinfo *cpu_bmap;
 
 	switch (vendor) {
 #ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
 	case THEAD_VENDOR_ID:
-		bmap = riscv_isa_vendor_ext_list_thead.vendor_bitmap;
-		cpu_bmap = riscv_isa_vendor_ext_list_thead.per_hart_vendor_bitmap;
-		bmap_size = riscv_isa_vendor_ext_list_thead.bitmap_size;
+		bmap = &riscv_isa_vendor_ext_list_thead.all_harts_isa_bitmap;
+		cpu_bmap = &riscv_isa_vendor_ext_list_thead.per_hart_isa_bitmap[cpu];
 		break;
 #endif
 	default:
@@ -48,11 +46,11 @@ bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsig
 	}
 
 	if (cpu != -1)
-		bmap = cpu_bmap[cpu].isa;
+		bmap = &cpu_bmap[cpu];
 
-	if (bit >= bmap_size)
+	if (bit >= RISCV_ISA_VENDOR_EXT_MAX)
 		return false;
 
-	return test_bit(bit, bmap) ? true : false;
+	return test_bit(bit, bmap->isa) ? true : false;
 }
 EXPORT_SYMBOL_GPL(__riscv_isa_vendor_extension_available);

-- 
2.44.0

[PATCH v5 09/17] riscv: Convert xandespmu to use the vendor extension framework

[Charlie Jenkins]

Migrate xandespmu out of riscv_isa_ext and into a new Andes-specific
vendor namespace.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/Kconfig.vendor                        | 12 ++++++++++++
 arch/riscv/errata/andes/errata.c                 |  2 ++
 arch/riscv/include/asm/hwcap.h                   |  1 -
 arch/riscv/include/asm/vendor_extensions/andes.h | 19 +++++++++++++++++++
 arch/riscv/kernel/cpufeature.c                   |  1 -
 arch/riscv/kernel/vendor_extensions.c            | 10 ++++++++++
 arch/riscv/kernel/vendor_extensions/Makefile     |  1 +
 arch/riscv/kernel/vendor_extensions/andes.c      | 18 ++++++++++++++++++
 drivers/perf/riscv_pmu_sbi.c                     |  9 ++++++---
 9 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor
index 85ac30496b0e..aa5a191e659e 100644
--- a/arch/riscv/Kconfig.vendor
+++ b/arch/riscv/Kconfig.vendor
@@ -16,4 +16,16 @@ config RISCV_ISA_VENDOR_EXT_THEAD
 	  If you don't know what to do here, say Y.
 endmenu
 
+menu "Andes"
+config RISCV_ISA_VENDOR_EXT_ANDES
+	bool "Andes vendor extension support"
+	default y
+	help
+	  Say N here if you want to disable all Andes vendor extension
+	  support. This will cause any Andes vendor extensions that are
+	  requested by hardware probing to be ignored.
+
+	  If you don't know what to do here, say Y.
+endmenu
+
 endmenu
diff --git a/arch/riscv/errata/andes/errata.c b/arch/riscv/errata/andes/errata.c
index f2708a9494a1..a5d96a7a4682 100644
--- a/arch/riscv/errata/andes/errata.c
+++ b/arch/riscv/errata/andes/errata.c
@@ -65,6 +65,8 @@ void __init_or_module andes_errata_patch_func(struct alt_entry *begin, struct al
 					      unsigned long archid, unsigned long impid,
 					      unsigned int stage)
 {
+	BUILD_BUG_ON(ERRATA_ANDES_NUMBER >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
+
 	if (stage == RISCV_ALTERNATIVES_BOOT)
 		errata_probe_iocp(stage, archid, impid);
 
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index e17d0078a651..1f2d2599c655 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -80,7 +80,6 @@
 #define RISCV_ISA_EXT_ZFA		71
 #define RISCV_ISA_EXT_ZTSO		72
 #define RISCV_ISA_EXT_ZACAS		73
-#define RISCV_ISA_EXT_XANDESPMU		74
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 
diff --git a/arch/riscv/include/asm/vendor_extensions/andes.h b/arch/riscv/include/asm/vendor_extensions/andes.h
new file mode 100644
index 000000000000..7bb2fc43438f
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions/andes.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_ANDES_H
+#define _ASM_RISCV_VENDOR_EXTENSIONS_ANDES_H
+
+#include <asm/vendor_extensions.h>
+
+#include <linux/types.h>
+
+#define RISCV_ISA_VENDOR_EXT_XANDESPMU		0
+
+/*
+ * Extension keys should be strictly less than max.
+ * It is safe to increment this when necessary.
+ */
+#define RISCV_ISA_VENDOR_EXT_MAX_ANDES			32
+
+extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_andes;
+
+#endif
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index b1f35564a1e0..0c9ba81600ac 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -289,7 +289,6 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
 	__RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT),
 	__RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
-	__RISCV_ISA_EXT_DATA(xandespmu, RISCV_ISA_EXT_XANDESPMU),
 };
 
 const size_t riscv_isa_ext_count = ARRAY_SIZE(riscv_isa_ext);
diff --git a/arch/riscv/kernel/vendor_extensions.c b/arch/riscv/kernel/vendor_extensions.c
index 7910890c17de..e4d58938e6ce 100644
--- a/arch/riscv/kernel/vendor_extensions.c
+++ b/arch/riscv/kernel/vendor_extensions.c
@@ -5,6 +5,7 @@
 
 #include <asm/vendorid_list.h>
 #include <asm/vendor_extensions.h>
+#include <asm/vendor_extensions/andes.h>
 #include <asm/vendor_extensions/thead.h>
 
 #include <linux/array_size.h>
@@ -14,6 +15,9 @@ struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[] = {
 #ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
 	&riscv_isa_vendor_ext_list_thead,
 #endif
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_ANDES
+	&riscv_isa_vendor_ext_list_andes,
+#endif
 };
 
 const size_t riscv_isa_vendor_ext_list_size = ARRAY_SIZE(riscv_isa_vendor_ext_list);
@@ -40,6 +44,12 @@ bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsig
 		bmap = &riscv_isa_vendor_ext_list_thead.all_harts_isa_bitmap;
 		cpu_bmap = &riscv_isa_vendor_ext_list_thead.per_hart_isa_bitmap[cpu];
 		break;
+#endif
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_ANDES
+	case ANDES_VENDOR_ID:
+		bmap = &riscv_isa_vendor_ext_list_andes.all_harts_isa_bitmap;
+		cpu_bmap = &riscv_isa_vendor_ext_list_andes.per_hart_isa_bitmap[cpu];
+		break;
 #endif
 	default:
 		return false;
diff --git a/arch/riscv/kernel/vendor_extensions/Makefile b/arch/riscv/kernel/vendor_extensions/Makefile
index 3383066baaab..8f1c5a4dc38f 100644
--- a/arch/riscv/kernel/vendor_extensions/Makefile
+++ b/arch/riscv/kernel/vendor_extensions/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD)	+= thead.o
+obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_ANDES)	+= andes.o
diff --git a/arch/riscv/kernel/vendor_extensions/andes.c b/arch/riscv/kernel/vendor_extensions/andes.c
new file mode 100644
index 000000000000..ec688c88456a
--- /dev/null
+++ b/arch/riscv/kernel/vendor_extensions/andes.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm/cpufeature.h>
+#include <asm/vendor_extensions.h>
+#include <asm/vendor_extensions/andes.h>
+
+#include <linux/array_size.h>
+#include <linux/types.h>
+
+/* All Andes vendor extensions supported in Linux */
+const struct riscv_isa_ext_data riscv_isa_vendor_ext_andes[] = {
+	__RISCV_ISA_EXT_DATA(xandespmu, RISCV_ISA_VENDOR_EXT_XANDESPMU),
+};
+
+struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_andes = {
+	.ext_data_count = ARRAY_SIZE(riscv_isa_vendor_ext_andes),
+	.ext_data = riscv_isa_vendor_ext_andes,
+};
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 8cbe6e5f9c39..d39b01372fa5 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -24,6 +24,8 @@
 #include <asm/errata_list.h>
 #include <asm/sbi.h>
 #include <asm/cpufeature.h>
+#include <asm/vendorid_list.h>
+#include <asm/vendor_extensions/andes.h>
 
 #define ALT_SBI_PMU_OVERFLOW(__ovl)					\
 asm volatile(ALTERNATIVE_2(						\
@@ -32,7 +34,7 @@ asm volatile(ALTERNATIVE_2(						\
 		THEAD_VENDOR_ID, ERRATA_THEAD_PMU,			\
 		CONFIG_ERRATA_THEAD_PMU,				\
 	"csrr %0, " __stringify(ANDES_CSR_SCOUNTEROF),			\
-		0, RISCV_ISA_EXT_XANDESPMU,				\
+		ANDES_VENDOR_ID, RISCV_ISA_VENDOR_EXT_XANDESPMU,	\
 		CONFIG_ANDES_CUSTOM_PMU)				\
 	: "=r" (__ovl) :						\
 	: "memory")
@@ -41,7 +43,7 @@ asm volatile(ALTERNATIVE_2(						\
 asm volatile(ALTERNATIVE(						\
 	"csrc " __stringify(CSR_IP) ", %0\n\t",				\
 	"csrc " __stringify(ANDES_CSR_SLIP) ", %0\n\t",			\
-		0, RISCV_ISA_EXT_XANDESPMU,				\
+		ANDES_VENDOR_ID, RISCV_ISA_VENDOR_EXT_XANDESPMU,	\
 		CONFIG_ANDES_CUSTOM_PMU)				\
 	: : "r"(__irq_mask)						\
 	: "memory")
@@ -837,7 +839,8 @@ static int pmu_sbi_setup_irqs(struct riscv_pmu *pmu, struct platform_device *pde
 		   riscv_cached_mimpid(0) == 0) {
 		riscv_pmu_irq_num = THEAD_C9XX_RV_IRQ_PMU;
 		riscv_pmu_use_irq = true;
-	} else if (riscv_isa_extension_available(NULL, XANDESPMU) &&
+	} else if (riscv_has_vendor_extension_unlikely(ANDES_VENDOR_ID,
+						       RISCV_ISA_VENDOR_EXT_XANDESPMU) &&
 		   IS_ENABLED(CONFIG_ANDES_CUSTOM_PMU)) {
 		riscv_pmu_irq_num = ANDES_SLI_CAUSE_BASE + ANDES_RV_IRQ_PMOVI;
 		riscv_pmu_use_irq = true;

-- 
2.44.0

[PATCH v5 10/17] RISC-V: define the elements of the VCSR vector CSR

[Charlie Jenkins]

From: Heiko Stuebner <heiko@sntech.de>

The VCSR CSR contains two elements VXRM[2:1] and VXSAT[0].

Define constants for those to access the elements in a readable way.

Acked-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/include/asm/csr.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 2468c55933cd..13bc99c995d1 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -215,6 +215,11 @@
 #define SMSTATEEN0_SSTATEEN0_SHIFT	63
 #define SMSTATEEN0_SSTATEEN0		(_ULL(1) << SMSTATEEN0_SSTATEEN0_SHIFT)
 
+/* VCSR flags */
+#define VCSR_VXRM_MASK			3
+#define VCSR_VXRM_SHIFT			1
+#define VCSR_VXSAT_MASK			1
+
 /* symbolic CSR names: */
 #define CSR_CYCLE		0xc00
 #define CSR_TIME		0xc01

-- 
2.44.0

[PATCH v5 11/17] riscv: csr: Add CSR encodings for VCSR_VXRM/VCSR_VXSAT

[Charlie Jenkins]

The VXRM vector csr for xtheadvector has an encoding of 0xa and VXSAT
has an encoding of 0x9.

Co-developed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/include/asm/csr.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 13bc99c995d1..e5a35efd56e0 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -219,6 +219,8 @@
 #define VCSR_VXRM_MASK			3
 #define VCSR_VXRM_SHIFT			1
 #define VCSR_VXSAT_MASK			1
+#define VCSR_VXSAT			0x9
+#define VCSR_VXRM			0xa
 
 /* symbolic CSR names: */
 #define CSR_CYCLE		0xc00

-- 
2.44.0

[PATCH v5 12/17] riscv: Add xtheadvector instruction definitions

[Charlie Jenkins]

xtheadvector uses different encodings than standard vector for
vsetvli and vector loads/stores. Write the instruction formats to be
used in assembly code.

Co-developed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/include/asm/vendor_extensions/thead.h | 26 ++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/riscv/include/asm/vendor_extensions/thead.h b/arch/riscv/include/asm/vendor_extensions/thead.h
index 48421d1553ad..27a253a20ab8 100644
--- a/arch/riscv/include/asm/vendor_extensions/thead.h
+++ b/arch/riscv/include/asm/vendor_extensions/thead.h
@@ -13,4 +13,30 @@
 
 extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead;
 
+/* Extension specific helpers */
+
+/*
+ * Vector 0.7.1 as used for example on T-Head Xuantie cores, uses an older
+ * encoding for vsetvli (ta, ma vs. d1), so provide an instruction for
+ * vsetvli	t4, x0, e8, m8, d1
+ */
+#define THEAD_VSETVLI_T4X0E8M8D1	".long	0x00307ed7\n\t"
+#define THEAD_VSETVLI_X0X0E8M8D1	".long	0x00307057\n\t"
+
+/*
+ * While in theory, the vector-0.7.1 vsb.v and vlb.v result in the same
+ * encoding as the standard vse8.v and vle8.v, compilers seem to optimize
+ * the call resulting in a different encoding and then using a value for
+ * the "mop" field that is not part of vector-0.7.1
+ * So encode specific variants for vstate_save and _restore.
+ */
+#define THEAD_VSB_V_V0T0		".long	0x02028027\n\t"
+#define THEAD_VSB_V_V8T0		".long	0x02028427\n\t"
+#define THEAD_VSB_V_V16T0		".long	0x02028827\n\t"
+#define THEAD_VSB_V_V24T0		".long	0x02028c27\n\t"
+#define THEAD_VLB_V_V0T0		".long	0x012028007\n\t"
+#define THEAD_VLB_V_V8T0		".long	0x012028407\n\t"
+#define THEAD_VLB_V_V16T0		".long	0x012028807\n\t"
+#define THEAD_VLB_V_V24T0		".long	0x012028c07\n\t"
+
 #endif

-- 
2.44.0

[PATCH v5 13/17] riscv: vector: Support xtheadvector save/restore

[Charlie Jenkins]

Use alternatives to add support for xtheadvector vector save/restore
routines.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/Kconfig.vendor              |  13 ++
 arch/riscv/include/asm/csr.h           |   6 +
 arch/riscv/include/asm/switch_to.h     |   2 +-
 arch/riscv/include/asm/vector.h        | 247 ++++++++++++++++++++++++++-------
 arch/riscv/kernel/cpufeature.c         |   2 +-
 arch/riscv/kernel/kernel_mode_vector.c |   8 +-
 arch/riscv/kernel/process.c            |   4 +-
 arch/riscv/kernel/signal.c             |   6 +-
 arch/riscv/kernel/vector.c             |  13 +-
 9 files changed, 233 insertions(+), 68 deletions(-)

diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor
index aa5a191e659e..edf49f3065ac 100644
--- a/arch/riscv/Kconfig.vendor
+++ b/arch/riscv/Kconfig.vendor
@@ -13,6 +13,19 @@ config RISCV_ISA_VENDOR_EXT_THEAD
 	  extensions. Without this option enabled, T-Head vendor extensions will
 	  not be detected at boot and their presence not reported to userspace.
 
+	  If you don't know what to do here, say Y.
+
+config RISCV_ISA_XTHEADVECTOR
+	bool "xtheadvector extension support"
+	depends on RISCV_ISA_VENDOR_EXT_THEAD
+	depends on RISCV_ISA_V
+	depends on FPU
+	default y
+	help
+	  Say N here if you want to disable all xtheadvector related procedure
+	  in the kernel. This will disable vector for any T-Head board that
+	  contains xtheadvector rather than the standard vector.
+
 	  If you don't know what to do here, say Y.
 endmenu
 
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index e5a35efd56e0..13657d096e7d 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -30,6 +30,12 @@
 #define SR_VS_CLEAN	_AC(0x00000400, UL)
 #define SR_VS_DIRTY	_AC(0x00000600, UL)
 
+#define SR_VS_THEAD		_AC(0x01800000, UL) /* xtheadvector Status */
+#define SR_VS_OFF_THEAD		_AC(0x00000000, UL)
+#define SR_VS_INITIAL_THEAD	_AC(0x00800000, UL)
+#define SR_VS_CLEAN_THEAD	_AC(0x01000000, UL)
+#define SR_VS_DIRTY_THEAD	_AC(0x01800000, UL)
+
 #define SR_XS		_AC(0x00018000, UL) /* Extension Status */
 #define SR_XS_OFF	_AC(0x00000000, UL)
 #define SR_XS_INITIAL	_AC(0x00008000, UL)
diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h
index 7efdb0584d47..ada6b5cf2d94 100644
--- a/arch/riscv/include/asm/switch_to.h
+++ b/arch/riscv/include/asm/switch_to.h
@@ -78,7 +78,7 @@ do {							\
 	struct task_struct *__next = (next);		\
 	if (has_fpu())					\
 		__switch_to_fpu(__prev, __next);	\
-	if (has_vector())					\
+	if (has_vector() || has_xtheadvector())		\
 		__switch_to_vector(__prev, __next);	\
 	((last) = __switch_to(__prev, __next));		\
 } while (0)
diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
index 731dcd0ed4de..db851dc81870 100644
--- a/arch/riscv/include/asm/vector.h
+++ b/arch/riscv/include/asm/vector.h
@@ -18,6 +18,27 @@
 #include <asm/cpufeature.h>
 #include <asm/csr.h>
 #include <asm/asm.h>
+#include <asm/vendorid_list.h>
+#include <asm/vendor_extensions.h>
+#include <asm/vendor_extensions/thead.h>
+
+#define __riscv_v_vstate_or(_val, TYPE) ({				\
+	typeof(_val) _res = _val;					\
+	if (has_xtheadvector()) \
+		_res = (_res & ~SR_VS_THEAD) | SR_VS_##TYPE##_THEAD;	\
+	else								\
+		_res = (_res & ~SR_VS) | SR_VS_##TYPE;			\
+	_res;								\
+})
+
+#define __riscv_v_vstate_check(_val, TYPE) ({				\
+	bool _res;							\
+	if (has_xtheadvector()) \
+		_res = ((_val) & SR_VS_THEAD) == SR_VS_##TYPE##_THEAD;	\
+	else								\
+		_res = ((_val) & SR_VS) == SR_VS_##TYPE;		\
+	_res;								\
+})
 
 extern unsigned long riscv_v_vsize;
 int riscv_v_setup_vsize(void);
@@ -40,39 +61,62 @@ static __always_inline bool has_vector(void)
 	return riscv_has_extension_unlikely(RISCV_ISA_EXT_v);
 }
 
+static __always_inline bool has_xtheadvector_no_alternatives(void)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR))
+		return riscv_isa_vendor_extension_available(THEAD_VENDOR_ID, XTHEADVECTOR);
+	else
+		return false;
+}
+
+static __always_inline bool has_xtheadvector(void)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR))
+		return riscv_has_vendor_extension_unlikely(THEAD_VENDOR_ID,
+							   RISCV_ISA_VENDOR_EXT_XTHEADVECTOR);
+	else
+		return false;
+}
+
 static inline void __riscv_v_vstate_clean(struct pt_regs *regs)
 {
-	regs->status = (regs->status & ~SR_VS) | SR_VS_CLEAN;
+	regs->status = __riscv_v_vstate_or(regs->status, CLEAN);
 }
 
 static inline void __riscv_v_vstate_dirty(struct pt_regs *regs)
 {
-	regs->status = (regs->status & ~SR_VS) | SR_VS_DIRTY;
+	regs->status = __riscv_v_vstate_or(regs->status, DIRTY);
 }
 
 static inline void riscv_v_vstate_off(struct pt_regs *regs)
 {
-	regs->status = (regs->status & ~SR_VS) | SR_VS_OFF;
+	regs->status = __riscv_v_vstate_or(regs->status, OFF);
 }
 
 static inline void riscv_v_vstate_on(struct pt_regs *regs)
 {
-	regs->status = (regs->status & ~SR_VS) | SR_VS_INITIAL;
+	regs->status = __riscv_v_vstate_or(regs->status, INITIAL);
 }
 
 static inline bool riscv_v_vstate_query(struct pt_regs *regs)
 {
-	return (regs->status & SR_VS) != 0;
+	return !__riscv_v_vstate_check(regs->status, OFF);
 }
 
 static __always_inline void riscv_v_enable(void)
 {
-	csr_set(CSR_SSTATUS, SR_VS);
+	if (has_xtheadvector())
+		csr_set(CSR_SSTATUS, SR_VS_THEAD);
+	else
+		csr_set(CSR_SSTATUS, SR_VS);
 }
 
 static __always_inline void riscv_v_disable(void)
 {
-	csr_clear(CSR_SSTATUS, SR_VS);
+	if (has_xtheadvector())
+		csr_clear(CSR_SSTATUS, SR_VS_THEAD);
+	else
+		csr_clear(CSR_SSTATUS, SR_VS);
 }
 
 static __always_inline void __vstate_csr_save(struct __riscv_v_ext_state *dest)
@@ -81,10 +125,47 @@ static __always_inline void __vstate_csr_save(struct __riscv_v_ext_state *dest)
 		"csrr	%0, " __stringify(CSR_VSTART) "\n\t"
 		"csrr	%1, " __stringify(CSR_VTYPE) "\n\t"
 		"csrr	%2, " __stringify(CSR_VL) "\n\t"
-		"csrr	%3, " __stringify(CSR_VCSR) "\n\t"
-		"csrr	%4, " __stringify(CSR_VLENB) "\n\t"
 		: "=r" (dest->vstart), "=r" (dest->vtype), "=r" (dest->vl),
-		  "=r" (dest->vcsr), "=r" (dest->vlenb) : :);
+		"=r" (dest->vcsr) : :);
+
+	if (has_xtheadvector()) {
+		u32 tmp_vcsr;
+		bool restore_fpu = false;
+		unsigned long status = csr_read(CSR_SSTATUS);
+
+		/*
+		 * CSR_VCSR is defined as
+		 * [2:1] - vxrm[1:0]
+		 * [0] - vxsat
+		 * The earlier vector spec implemented by T-Head uses separate
+		 * registers for the same bit-elements, so just combine those
+		 * into the existing output field.
+		 *
+		 * Additionally T-Head cores need FS to be enabled when accessing
+		 * the VXRM and VXSAT CSRs, otherwise ending in illegal instructions.
+		 * Though the cores do not implement the VXRM and VXSAT fields in the
+		 * FCSR CSR that vector-0.7.1 specifies.
+		 */
+		if ((status & SR_FS) == SR_FS_OFF) {
+			csr_set(CSR_SSTATUS, (status & ~SR_FS) | SR_FS_CLEAN);
+			restore_fpu = true;
+		}
+
+		asm volatile (
+			"csrr	%[tmp_vcsr], " __stringify(VCSR_VXRM) "\n\t"
+			"slliw	%[vcsr], %[tmp_vcsr], " __stringify(VCSR_VXRM_SHIFT) "\n\t"
+			"csrr	%[tmp_vcsr], " __stringify(VCSR_VXSAT) "\n\t"
+			"or	%[vcsr], %[vcsr], %[tmp_vcsr]\n\t"
+			: [vcsr] "=r" (dest->vcsr), [tmp_vcsr] "=&r" (tmp_vcsr));
+
+		if (restore_fpu)
+			csr_set(CSR_SSTATUS, status);
+	} else {
+		asm volatile (
+			"csrr	%[vcsr], " __stringify(CSR_VCSR) "\n\t"
+			"csrr	%[vlenb], " __stringify(CSR_VLENB) "\n\t"
+			: [vcsr] "=r" (dest->vcsr), [vlenb] "=r" (dest->vlenb));
+	}
 }
 
 static __always_inline void __vstate_csr_restore(struct __riscv_v_ext_state *src)
@@ -95,9 +176,37 @@ static __always_inline void __vstate_csr_restore(struct __riscv_v_ext_state *src
 		"vsetvl	 x0, %2, %1\n\t"
 		".option pop\n\t"
 		"csrw	" __stringify(CSR_VSTART) ", %0\n\t"
-		"csrw	" __stringify(CSR_VCSR) ", %3\n\t"
-		: : "r" (src->vstart), "r" (src->vtype), "r" (src->vl),
-		    "r" (src->vcsr) :);
+		: : "r" (src->vstart), "r" (src->vtype), "r" (src->vl));
+
+	if (has_xtheadvector()) {
+		u32 tmp_vcsr;
+		bool restore_fpu = false;
+		unsigned long status = csr_read(CSR_SSTATUS);
+
+		/*
+		 * Similar to __vstate_csr_save above, restore values for the
+		 * separate VXRM and VXSAT CSRs from the vcsr variable.
+		 */
+		if ((status & SR_FS) == SR_FS_OFF) {
+			csr_set(CSR_SSTATUS, (status & ~SR_FS) | SR_FS_CLEAN);
+			restore_fpu = true;
+		}
+
+		asm volatile (
+			"srliw	%[tmp_vcsr], %[vcsr], " __stringify(VCSR_VXRM_SHIFT) "\n\t"
+			"andi	%[tmp_vcsr], %[tmp_vcsr], " __stringify(VCSR_VXRM_MASK) "\n\t"
+			"csrw	" __stringify(VCSR_VXRM) ", %[tmp_vcsr]\n\t"
+			"andi	%[tmp_vcsr], %[vcsr], " __stringify(VCSR_VXSAT_MASK) "\n\t"
+			"csrw	" __stringify(VCSR_VXSAT) ", %[tmp_vcsr]\n\t"
+			: [tmp_vcsr] "=&r" (tmp_vcsr) : [vcsr] "r" (src->vcsr));
+
+		if (restore_fpu)
+			csr_set(CSR_SSTATUS, status);
+	} else {
+		asm volatile (
+			"csrw	" __stringify(CSR_VCSR) ", %[vcsr]\n\t"
+			: : [vcsr] "r" (src->vcsr));
+	}
 }
 
 static inline void __riscv_v_vstate_save(struct __riscv_v_ext_state *save_to,
@@ -107,19 +216,33 @@ static inline void __riscv_v_vstate_save(struct __riscv_v_ext_state *save_to,
 
 	riscv_v_enable();
 	__vstate_csr_save(save_to);
-	asm volatile (
-		".option push\n\t"
-		".option arch, +v\n\t"
-		"vsetvli	%0, x0, e8, m8, ta, ma\n\t"
-		"vse8.v		v0, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vse8.v		v8, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vse8.v		v16, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vse8.v		v24, (%1)\n\t"
-		".option pop\n\t"
-		: "=&r" (vl) : "r" (datap) : "memory");
+	if (has_xtheadvector()) {
+		asm volatile (
+			"mv t0, %0\n\t"
+			THEAD_VSETVLI_T4X0E8M8D1
+			THEAD_VSB_V_V0T0
+			"add		t0, t0, t4\n\t"
+			THEAD_VSB_V_V0T0
+			"add		t0, t0, t4\n\t"
+			THEAD_VSB_V_V0T0
+			"add		t0, t0, t4\n\t"
+			THEAD_VSB_V_V0T0
+			: : "r" (datap) : "memory", "t0", "t4");
+	} else {
+		asm volatile (
+			".option push\n\t"
+			".option arch, +v\n\t"
+			"vsetvli	%0, x0, e8, m8, ta, ma\n\t"
+			"vse8.v		v0, (%1)\n\t"
+			"add		%1, %1, %0\n\t"
+			"vse8.v		v8, (%1)\n\t"
+			"add		%1, %1, %0\n\t"
+			"vse8.v		v16, (%1)\n\t"
+			"add		%1, %1, %0\n\t"
+			"vse8.v		v24, (%1)\n\t"
+			".option pop\n\t"
+			: "=&r" (vl) : "r" (datap) : "memory");
+	}
 	riscv_v_disable();
 }
 
@@ -129,55 +252,77 @@ static inline void __riscv_v_vstate_restore(struct __riscv_v_ext_state *restore_
 	unsigned long vl;
 
 	riscv_v_enable();
-	asm volatile (
-		".option push\n\t"
-		".option arch, +v\n\t"
-		"vsetvli	%0, x0, e8, m8, ta, ma\n\t"
-		"vle8.v		v0, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vle8.v		v8, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vle8.v		v16, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vle8.v		v24, (%1)\n\t"
-		".option pop\n\t"
-		: "=&r" (vl) : "r" (datap) : "memory");
+	if (has_xtheadvector()) {
+		asm volatile (
+			"mv t0, %0\n\t"
+			THEAD_VSETVLI_T4X0E8M8D1
+			THEAD_VLB_V_V0T0
+			"add		t0, t0, t4\n\t"
+			THEAD_VLB_V_V0T0
+			"add		t0, t0, t4\n\t"
+			THEAD_VLB_V_V0T0
+			"add		t0, t0, t4\n\t"
+			THEAD_VLB_V_V0T0
+			: : "r" (datap) : "memory", "t0", "t4");
+	} else {
+		asm volatile (
+			".option push\n\t"
+			".option arch, +v\n\t"
+			"vsetvli	%0, x0, e8, m8, ta, ma\n\t"
+			"vle8.v		v0, (%1)\n\t"
+			"add		%1, %1, %0\n\t"
+			"vle8.v		v8, (%1)\n\t"
+			"add		%1, %1, %0\n\t"
+			"vle8.v		v16, (%1)\n\t"
+			"add		%1, %1, %0\n\t"
+			"vle8.v		v24, (%1)\n\t"
+			".option pop\n\t"
+			: "=&r" (vl) : "r" (datap) : "memory");
+	}
 	__vstate_csr_restore(restore_from);
 	riscv_v_disable();
 }
 
 static inline void __riscv_v_vstate_discard(void)
 {
-	unsigned long vl, vtype_inval = 1UL << (BITS_PER_LONG - 1);
+	unsigned long vtype_inval = 1UL << (BITS_PER_LONG - 1);
 
 	riscv_v_enable();
+	if (has_xtheadvector())
+		asm volatile (THEAD_VSETVLI_X0X0E8M8D1);
+	else
+		asm volatile (
+			".option push\n\t"
+			".option arch, +v\n\t"
+			"vsetvli	x0, x0, e8, m8, ta, ma\n\t"
+			".option pop\n\t");
+
 	asm volatile (
 		".option push\n\t"
 		".option arch, +v\n\t"
-		"vsetvli	%0, x0, e8, m8, ta, ma\n\t"
 		"vmv.v.i	v0, -1\n\t"
 		"vmv.v.i	v8, -1\n\t"
 		"vmv.v.i	v16, -1\n\t"
 		"vmv.v.i	v24, -1\n\t"
-		"vsetvl		%0, x0, %1\n\t"
+		"vsetvl		x0, x0, %0\n\t"
 		".option pop\n\t"
-		: "=&r" (vl) : "r" (vtype_inval) : "memory");
+		: : "r" (vtype_inval));
+
 	riscv_v_disable();
 }
 
 static inline void riscv_v_vstate_discard(struct pt_regs *regs)
 {
-	if ((regs->status & SR_VS) == SR_VS_OFF)
-		return;
-
-	__riscv_v_vstate_discard();
-	__riscv_v_vstate_dirty(regs);
+	if (riscv_v_vstate_query(regs)) {
+		__riscv_v_vstate_discard();
+		__riscv_v_vstate_dirty(regs);
+	}
 }
 
 static inline void riscv_v_vstate_save(struct __riscv_v_ext_state *vstate,
 				       struct pt_regs *regs)
 {
-	if ((regs->status & SR_VS) == SR_VS_DIRTY) {
+	if (__riscv_v_vstate_check(regs->status, DIRTY)) {
 		__riscv_v_vstate_save(vstate, vstate->datap);
 		__riscv_v_vstate_clean(regs);
 	}
@@ -186,7 +331,7 @@ static inline void riscv_v_vstate_save(struct __riscv_v_ext_state *vstate,
 static inline void riscv_v_vstate_restore(struct __riscv_v_ext_state *vstate,
 					  struct pt_regs *regs)
 {
-	if ((regs->status & SR_VS) != SR_VS_OFF) {
+	if (riscv_v_vstate_query(regs)) {
 		__riscv_v_vstate_restore(vstate, vstate->datap);
 		__riscv_v_vstate_clean(regs);
 	}
@@ -195,7 +340,7 @@ static inline void riscv_v_vstate_restore(struct __riscv_v_ext_state *vstate,
 static inline void riscv_v_vstate_set_restore(struct task_struct *task,
 					      struct pt_regs *regs)
 {
-	if ((regs->status & SR_VS) != SR_VS_OFF) {
+	if (riscv_v_vstate_query(regs)) {
 		set_tsk_thread_flag(task, TIF_RISCV_V_DEFER_RESTORE);
 		riscv_v_vstate_on(regs);
 	}
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 0c9ba81600ac..5366f1a4485e 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -777,7 +777,7 @@ void __init riscv_fill_hwcap(void)
 		elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
 	}
 
-	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+	if (elf_hwcap & COMPAT_HWCAP_ISA_V || has_xtheadvector_no_alternatives()) {
 		riscv_v_setup_vsize();
 		/*
 		 * ISA string in device tree might have 'v' flag, but
diff --git a/arch/riscv/kernel/kernel_mode_vector.c b/arch/riscv/kernel/kernel_mode_vector.c
index 6afe80c7f03a..99972a48e86b 100644
--- a/arch/riscv/kernel/kernel_mode_vector.c
+++ b/arch/riscv/kernel/kernel_mode_vector.c
@@ -143,7 +143,7 @@ static int riscv_v_start_kernel_context(bool *is_nested)
 
 	/* Transfer the ownership of V from user to kernel, then save */
 	riscv_v_start(RISCV_PREEMPT_V | RISCV_PREEMPT_V_DIRTY);
-	if ((task_pt_regs(current)->status & SR_VS) == SR_VS_DIRTY) {
+	if (__riscv_v_vstate_check(task_pt_regs(current)->status, DIRTY)) {
 		uvstate = &current->thread.vstate;
 		__riscv_v_vstate_save(uvstate, uvstate->datap);
 	}
@@ -160,7 +160,7 @@ asmlinkage void riscv_v_context_nesting_start(struct pt_regs *regs)
 		return;
 
 	depth = riscv_v_ctx_get_depth();
-	if (depth == 0 && (regs->status & SR_VS) == SR_VS_DIRTY)
+	if (depth == 0 && __riscv_v_vstate_check(regs->status, DIRTY))
 		riscv_preempt_v_set_dirty();
 
 	riscv_v_ctx_depth_inc();
@@ -208,7 +208,7 @@ void kernel_vector_begin(void)
 {
 	bool nested = false;
 
-	if (WARN_ON(!has_vector()))
+	if (WARN_ON(!(has_vector() || has_xtheadvector())))
 		return;
 
 	BUG_ON(!may_use_simd());
@@ -236,7 +236,7 @@ EXPORT_SYMBOL_GPL(kernel_vector_begin);
  */
 void kernel_vector_end(void)
 {
-	if (WARN_ON(!has_vector()))
+	if (WARN_ON(!(has_vector() || has_xtheadvector())))
 		return;
 
 	riscv_v_disable();
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 92922dbd5b5c..eabca86fc3c0 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -178,7 +178,7 @@ void flush_thread(void)
 void arch_release_task_struct(struct task_struct *tsk)
 {
 	/* Free the vector context of datap. */
-	if (has_vector())
+	if (has_vector() || has_xtheadvector())
 		riscv_v_thread_free(tsk);
 }
 
@@ -225,7 +225,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 		p->thread.s[0] = 0;
 	}
 	p->thread.riscv_v_flags = 0;
-	if (has_vector())
+	if (has_vector() || has_xtheadvector())
 		riscv_v_thread_alloc(p);
 	p->thread.ra = (unsigned long)ret_from_fork;
 	p->thread.sp = (unsigned long)childregs; /* kernel sp */
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 501e66debf69..5d3ba8e46807 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -188,7 +188,7 @@ static long restore_sigcontext(struct pt_regs *regs,
 
 			return 0;
 		case RISCV_V_MAGIC:
-			if (!has_vector() || !riscv_v_vstate_query(regs) ||
+			if (!(has_vector() || has_xtheadvector()) || !riscv_v_vstate_query(regs) ||
 			    size != riscv_v_sc_size)
 				return -EINVAL;
 
@@ -210,7 +210,7 @@ static size_t get_rt_frame_size(bool cal_all)
 
 	frame_size = sizeof(*frame);
 
-	if (has_vector()) {
+	if (has_vector() || has_xtheadvector()) {
 		if (cal_all || riscv_v_vstate_query(task_pt_regs(current)))
 			total_context_size += riscv_v_sc_size;
 	}
@@ -283,7 +283,7 @@ static long setup_sigcontext(struct rt_sigframe __user *frame,
 	if (has_fpu())
 		err |= save_fp_state(regs, &sc->sc_fpregs);
 	/* Save the vector state. */
-	if (has_vector() && riscv_v_vstate_query(regs))
+	if ((has_vector() || has_xtheadvector()) && riscv_v_vstate_query(regs))
 		err |= save_v_state(regs, (void __user **)&sc_ext_ptr);
 	/* Write zero to fp-reserved space and check it on restore_sigcontext */
 	err |= __put_user(0, &sc->sc_extdesc.reserved);
diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
index e04586cdb7f0..c12ea4547da6 100644
--- a/arch/riscv/kernel/vector.c
+++ b/arch/riscv/kernel/vector.c
@@ -63,7 +63,7 @@ int riscv_v_setup_vsize(void)
 
 void __init riscv_v_setup_ctx_cache(void)
 {
-	if (!has_vector())
+	if (!(has_vector() || has_xtheadvector()))
 		return;
 
 	riscv_v_user_cachep = kmem_cache_create_usercopy("riscv_vector_ctx",
@@ -184,7 +184,8 @@ bool riscv_v_first_use_handler(struct pt_regs *regs)
 	u32 insn = (u32)regs->badaddr;
 
 	/* Do not handle if V is not supported, or disabled */
-	if (!(ELF_HWCAP & COMPAT_HWCAP_ISA_V))
+	if (!(ELF_HWCAP & COMPAT_HWCAP_ISA_V) &&
+	    !(has_xtheadvector() && riscv_v_vstate_ctrl_user_allowed()))
 		return false;
 
 	/* If V has been enabled then it is not the first-use trap */
@@ -223,7 +224,7 @@ void riscv_v_vstate_ctrl_init(struct task_struct *tsk)
 	bool inherit;
 	int cur, next;
 
-	if (!has_vector())
+	if (!(has_vector() || has_xtheadvector()))
 		return;
 
 	next = riscv_v_ctrl_get_next(tsk);
@@ -245,7 +246,7 @@ void riscv_v_vstate_ctrl_init(struct task_struct *tsk)
 
 long riscv_v_vstate_ctrl_get_current(void)
 {
-	if (!has_vector())
+	if (!(has_vector() || has_xtheadvector()))
 		return -EINVAL;
 
 	return current->thread.vstate_ctrl & PR_RISCV_V_VSTATE_CTRL_MASK;
@@ -256,7 +257,7 @@ long riscv_v_vstate_ctrl_set_current(unsigned long arg)
 	bool inherit;
 	int cur, next;
 
-	if (!has_vector())
+	if (!(has_vector() || has_xtheadvector()))
 		return -EINVAL;
 
 	if (arg & ~PR_RISCV_V_VSTATE_CTRL_MASK)
@@ -306,7 +307,7 @@ static struct ctl_table riscv_v_default_vstate_table[] = {
 
 static int __init riscv_v_sysctl_init(void)
 {
-	if (has_vector())
+	if (has_vector() || has_xtheadvector())
 		if (!register_sysctl("abi", riscv_v_default_vstate_table))
 			return -EINVAL;
 	return 0;

-- 
2.44.0

[PATCH v5 14/17] riscv: hwprobe: Add thead vendor extension probing

[Charlie Jenkins]

Add a new hwprobe key "RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0" which
allows userspace to probe for the new RISCV_ISA_VENDOR_EXT_XTHEADVECTOR
vendor extension.

This new key will allow userspace code to probe for which thead vendor
extensions are supported. This API is modeled to be consistent with
RISCV_HWPROBE_KEY_IMA_EXT_0. The bitmask returned will have each bit
corresponding to a supported thead vendor extension of the cpumask set.
Just like RISCV_HWPROBE_KEY_IMA_EXT_0, this allows a userspace program
to determine all of the supported thead vendor extensions in one call.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/include/asm/hwprobe.h                   |  4 +--
 .../include/asm/vendor_extensions/thead_hwprobe.h  | 18 ++++++++++++
 .../include/asm/vendor_extensions/vendor_hwprobe.h | 34 ++++++++++++++++++++++
 arch/riscv/include/uapi/asm/hwprobe.h              |  3 +-
 arch/riscv/include/uapi/asm/vendor/thead.h         |  3 ++
 arch/riscv/kernel/sys_hwprobe.c                    |  5 ++++
 arch/riscv/kernel/vendor_extensions/Makefile       |  1 +
 .../riscv/kernel/vendor_extensions/thead_hwprobe.c | 19 ++++++++++++
 8 files changed, 84 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
index 630507dff5ea..e68496b4f8de 100644
--- a/arch/riscv/include/asm/hwprobe.h
+++ b/arch/riscv/include/asm/hwprobe.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
- * Copyright 2023 Rivos, Inc
+ * Copyright 2023-2024 Rivos, Inc
  */
 
 #ifndef _ASM_HWPROBE_H
@@ -8,7 +8,7 @@
 
 #include <uapi/asm/hwprobe.h>
 
-#define RISCV_HWPROBE_MAX_KEY 6
+#define RISCV_HWPROBE_MAX_KEY 7
 
 static inline bool riscv_hwprobe_key_is_valid(__s64 key)
 {
diff --git a/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h b/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h
new file mode 100644
index 000000000000..925fef39a2c0
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_HWPROBE_H
+#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_HWPROBE_H
+
+#include <linux/cpumask.h>
+
+#include <uapi/asm/hwprobe.h>
+
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
+void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus);
+#else
+static inline void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus)
+{
+	pair->value = 0;
+}
+#endif
+
+#endif
diff --git a/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h b/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h
new file mode 100644
index 000000000000..2a29f1a5cae3
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2024 Rivos, Inc
+ */
+
+#ifndef _ASM_RISCV_SYS_HWPROBE_H
+#define _ASM_RISCV_SYS_HWPROBE_H
+
+#include <asm/cpufeature.h>
+
+#define EXT_KEY(ext)									\
+	do {										\
+		if (__riscv_isa_extension_available(isainfo->isa, RISCV_ISA_VENDOR_EXT_##ext)) \
+			pair->value |= RISCV_HWPROBE_VENDOR_EXT_##ext;			\
+		else									\
+			missing |= RISCV_HWPROBE_VENDOR_EXT_##ext;			\
+	} while (false)
+
+/*
+ * Loop through and record extensions that 1) anyone has, and 2) anyone
+ * doesn't have.
+ */
+#define VENDOR_EXTENSION_SUPPORTED(pair, cpus, per_hart_thead_bitmap, ...)			\
+	do {											\
+		int cpu;									\
+		u64 missing;									\
+		for_each_cpu(cpu, (cpus)) {							\
+			struct riscv_isavendorinfo *isainfo = &(per_hart_thead_bitmap)[cpu];	\
+			__VA_ARGS__								\
+		}										\
+		(pair)->value &= ~missing;							\
+	} while (false)										\
+
+#endif /* _ASM_RISCV_SYS_HWPROBE_H */
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index 9f2a8e3ff204..21e96a63f9ea 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
- * Copyright 2023 Rivos, Inc
+ * Copyright 2023-2024 Rivos, Inc
  */
 
 #ifndef _UAPI_ASM_HWPROBE_H
@@ -67,6 +67,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_MISALIGNED_UNSUPPORTED	(4 << 0)
 #define		RISCV_HWPROBE_MISALIGNED_MASK		(7 << 0)
 #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE	6
+#define RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0	7
 /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
 
 /* Flags */
diff --git a/arch/riscv/include/uapi/asm/vendor/thead.h b/arch/riscv/include/uapi/asm/vendor/thead.h
new file mode 100644
index 000000000000..43790ebe5faf
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/vendor/thead.h
@@ -0,0 +1,3 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#define		RISCV_HWPROBE_VENDOR_EXT_XTHEADVECTOR	(1 << 0)
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index 8cae41a502dd..aeb70afe230b 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -13,6 +13,7 @@
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include <asm/vector.h>
+#include <asm/vendor_extensions/thead_hwprobe.h>
 #include <vdso/vsyscall.h>
 
 
@@ -216,6 +217,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
 			pair->value = riscv_cboz_block_size;
 		break;
 
+	case RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0:
+		hwprobe_isa_vendor_ext_thead_0(pair, cpus);
+		break;
+
 	/*
 	 * For forward compatibility, unknown keys don't fail the whole
 	 * call, but get their element key set to -1 and value set to 0
diff --git a/arch/riscv/kernel/vendor_extensions/Makefile b/arch/riscv/kernel/vendor_extensions/Makefile
index 8f1c5a4dc38f..f511fd269e8a 100644
--- a/arch/riscv/kernel/vendor_extensions/Makefile
+++ b/arch/riscv/kernel/vendor_extensions/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD)	+= thead.o
+obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD)	+= thead_hwprobe.o
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_ANDES)	+= andes.o
diff --git a/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c b/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c
new file mode 100644
index 000000000000..53f65942f7e8
--- /dev/null
+++ b/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm/vendor_extensions/thead.h>
+#include <asm/vendor_extensions/thead_hwprobe.h>
+#include <asm/vendor_extensions/vendor_hwprobe.h>
+
+#include <linux/cpumask.h>
+#include <linux/types.h>
+
+#include <uapi/asm/hwprobe.h>
+#include <uapi/asm/vendor/thead.h>
+
+void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus)
+{
+	VENDOR_EXTENSION_SUPPORTED(pair, cpus,
+				   riscv_isa_vendor_ext_list_thead.per_hart_isa_bitmap, {
+		EXT_KEY(XTHEADVECTOR);
+	});
+}

-- 
2.44.0

[PATCH v5 15/17] riscv: hwprobe: Document thead vendor extensions and xtheadvector extension

[Charlie Jenkins]

Document support for thead vendor extensions using the key
RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 and xtheadvector extension using
the key RISCV_HWPROBE_VENDOR_EXT_XTHEADVECTOR.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 Documentation/arch/riscv/hwprobe.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index b2bcc9eed9aa..b2bb305140aa 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -210,3 +210,13 @@ The following keys are defined:
 
 * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
   represents the size of the Zicboz block in bytes.
+
+* :c:macro:`RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0`: A bitmask containing the
+  thead vendor extensions that are compatible with the
+  :c:macro:`RISCV_HWPROBE_BASE_BEHAVIOR_IMA`: base system behavior.
+
+  * T-HEAD
+
+    * :c:macro:`RISCV_HWPROBE_VENDOR_EXT_XTHEADVECTOR`: The xtheadvector vendor
+        extension is supported in the T-Head ISA extensions spec starting from
+	commit a18c801634 ("Add T-Head VECTOR vendor extension. ").

-- 
2.44.0

[PATCH v5 16/17] selftests: riscv: Fix vector tests

[Charlie Jenkins]

Overhaul the riscv vector tests to use kselftest_harness to help the
test cases correctly report the results and decouple the individual test
cases from each other. With this refactoring, only run the test cases is
vector is reported and properly report the test case as skipped
otherwise. The v_initval_nolibc test was previously not checking if
vector was supported and used a function (malloc) which invalidates
the state of the vector registers.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 tools/testing/selftests/riscv/vector/.gitignore    |   3 +-
 tools/testing/selftests/riscv/vector/Makefile      |  17 +-
 .../selftests/riscv/vector/v_exec_initval_nolibc.c |  84 +++++++
 tools/testing/selftests/riscv/vector/v_helpers.c   |  56 +++++
 tools/testing/selftests/riscv/vector/v_helpers.h   |   5 +
 tools/testing/selftests/riscv/vector/v_initval.c   |  16 ++
 .../selftests/riscv/vector/v_initval_nolibc.c      |  68 ------
 .../testing/selftests/riscv/vector/vstate_prctl.c  | 266 ++++++++++++---------
 8 files changed, 324 insertions(+), 191 deletions(-)

diff --git a/tools/testing/selftests/riscv/vector/.gitignore b/tools/testing/selftests/riscv/vector/.gitignore
index 9ae7964491d5..7d9c87cd0649 100644
--- a/tools/testing/selftests/riscv/vector/.gitignore
+++ b/tools/testing/selftests/riscv/vector/.gitignore
@@ -1,3 +1,4 @@
 vstate_exec_nolibc
 vstate_prctl
-v_initval_nolibc
+v_initval
+v_exec_initval_nolibc
diff --git a/tools/testing/selftests/riscv/vector/Makefile b/tools/testing/selftests/riscv/vector/Makefile
index bfff0ff4f3be..995746359477 100644
--- a/tools/testing/selftests/riscv/vector/Makefile
+++ b/tools/testing/selftests/riscv/vector/Makefile
@@ -2,18 +2,27 @@
 # Copyright (C) 2021 ARM Limited
 # Originally tools/testing/arm64/abi/Makefile
 
-TEST_GEN_PROGS := vstate_prctl v_initval_nolibc
-TEST_GEN_PROGS_EXTENDED := vstate_exec_nolibc
+TEST_GEN_PROGS := v_initval vstate_prctl
+TEST_GEN_PROGS_EXTENDED := vstate_exec_nolibc v_exec_initval_nolibc sys_hwprobe.o v_helpers.o
 
 include ../../lib.mk
 
-$(OUTPUT)/vstate_prctl: vstate_prctl.c ../hwprobe/sys_hwprobe.S
+$(OUTPUT)/sys_hwprobe.o: ../hwprobe/sys_hwprobe.S
+	$(CC) -static -c -o$@ $(CFLAGS) $^
+
+$(OUTPUT)/v_helpers.o: v_helpers.c
+	$(CC) -static -c -o$@ $(CFLAGS) $^
+
+$(OUTPUT)/vstate_prctl: vstate_prctl.c $(OUTPUT)/sys_hwprobe.o $(OUTPUT)/v_helpers.o
 	$(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
 
 $(OUTPUT)/vstate_exec_nolibc: vstate_exec_nolibc.c
 	$(CC) -nostdlib -static -include ../../../../include/nolibc/nolibc.h \
 		-Wall $(CFLAGS) $(LDFLAGS) $^ -o $@ -lgcc
 
-$(OUTPUT)/v_initval_nolibc: v_initval_nolibc.c
+$(OUTPUT)/v_initval: v_initval.c $(OUTPUT)/sys_hwprobe.o $(OUTPUT)/v_helpers.o
+	$(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
+
+$(OUTPUT)/v_exec_initval_nolibc: v_exec_initval_nolibc.c
 	$(CC) -nostdlib -static -include ../../../../include/nolibc/nolibc.h \
 		-Wall $(CFLAGS) $(LDFLAGS) $^ -o $@ -lgcc
diff --git a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
new file mode 100644
index 000000000000..74b13806baf0
--- /dev/null
+++ b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Get values of vector registers as soon as the program starts to test if
+ * is properly cleaning the values before starting a new program. Vector
+ * registers are caller saved, so no function calls may happen before reading
+ * the values. To further ensure consistency, this file is compiled without
+ * libc and without auto-vectorization.
+ *
+ * To be "clean" all values must be either all ones or all zeroes.
+ */
+
+#define __stringify_1(x...)	#x
+#define __stringify(x...)	__stringify_1(x)
+
+int main(int argc, char **argv)
+{
+	char prev_value = 0, value;
+	unsigned long vl;
+	int first = 1;
+
+	asm volatile (
+		".option push\n\t"
+		".option arch, +v\n\t"
+		"vsetvli	%[vl], x0, e8, m1, ta, ma\n\t"
+		".option pop\n\t"
+		: [vl] "=r" (vl)
+	);
+
+#define CHECK_VECTOR_REGISTER(register) ({					\
+	for (int i = 0; i < vl; i++) {						\
+		asm volatile (							\
+			".option push\n\t"					\
+			".option arch, +v\n\t"					\
+			"vmv.x.s %0, " __stringify(register) "\n\t"		\
+			"vsrl.vi " __stringify(register) ", " __stringify(register) ", 8\n\t" \
+			".option pop\n\t"					\
+			: "=r" (value));					\
+		if (first) {							\
+			first = 0;						\
+		} else if (value != prev_value || !(value == 0x00 || value == 0xff)) { \
+			printf("Register " __stringify(register) " values not clean! value: %u\n", value);	\
+			exit(-1);						\
+		}								\
+		prev_value = value;						\
+	}									\
+})
+
+	CHECK_VECTOR_REGISTER(v0);
+	CHECK_VECTOR_REGISTER(v1);
+	CHECK_VECTOR_REGISTER(v2);
+	CHECK_VECTOR_REGISTER(v3);
+	CHECK_VECTOR_REGISTER(v4);
+	CHECK_VECTOR_REGISTER(v5);
+	CHECK_VECTOR_REGISTER(v6);
+	CHECK_VECTOR_REGISTER(v7);
+	CHECK_VECTOR_REGISTER(v8);
+	CHECK_VECTOR_REGISTER(v9);
+	CHECK_VECTOR_REGISTER(v10);
+	CHECK_VECTOR_REGISTER(v11);
+	CHECK_VECTOR_REGISTER(v12);
+	CHECK_VECTOR_REGISTER(v13);
+	CHECK_VECTOR_REGISTER(v14);
+	CHECK_VECTOR_REGISTER(v15);
+	CHECK_VECTOR_REGISTER(v16);
+	CHECK_VECTOR_REGISTER(v17);
+	CHECK_VECTOR_REGISTER(v18);
+	CHECK_VECTOR_REGISTER(v19);
+	CHECK_VECTOR_REGISTER(v20);
+	CHECK_VECTOR_REGISTER(v21);
+	CHECK_VECTOR_REGISTER(v22);
+	CHECK_VECTOR_REGISTER(v23);
+	CHECK_VECTOR_REGISTER(v24);
+	CHECK_VECTOR_REGISTER(v25);
+	CHECK_VECTOR_REGISTER(v26);
+	CHECK_VECTOR_REGISTER(v27);
+	CHECK_VECTOR_REGISTER(v28);
+	CHECK_VECTOR_REGISTER(v29);
+	CHECK_VECTOR_REGISTER(v30);
+	CHECK_VECTOR_REGISTER(v31);
+
+#undef CHECK_VECTOR_REGISTER
+
+	return 0;
+}
diff --git a/tools/testing/selftests/riscv/vector/v_helpers.c b/tools/testing/selftests/riscv/vector/v_helpers.c
new file mode 100644
index 000000000000..15c22318db72
--- /dev/null
+++ b/tools/testing/selftests/riscv/vector/v_helpers.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "../hwprobe/hwprobe.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+int is_vector_supported(void)
+{
+	struct riscv_hwprobe pair;
+
+	pair.key = RISCV_HWPROBE_KEY_IMA_EXT_0;
+	riscv_hwprobe(&pair, 1, 0, NULL, 0);
+	return pair.value & RISCV_HWPROBE_IMA_V;
+}
+
+int launch_test(char *next_program, int test_inherit)
+{
+	char *exec_argv[3], *exec_envp[1];
+	int rc, pid, status;
+
+	pid = fork();
+	if (pid < 0) {
+		printf("fork failed %d", pid);
+		return -1;
+	}
+
+	if (!pid) {
+		exec_argv[0] = next_program;
+		exec_argv[1] = test_inherit != 0 ? "x" : NULL;
+		exec_argv[2] = NULL;
+		exec_envp[0] = NULL;
+		/* launch the program again to check inherit */
+		rc = execve(next_program, exec_argv, exec_envp);
+		if (rc) {
+			perror("execve");
+			printf("child execve failed %d\n", rc);
+			exit(-1);
+		}
+	}
+
+	rc = waitpid(-1, &status, 0);
+	if (rc < 0) {
+		printf("waitpid failed\n");
+		return -3;
+	}
+
+	if ((WIFEXITED(status) && WEXITSTATUS(status) == -1) ||
+	    WIFSIGNALED(status)) {
+		printf("child exited abnormally\n");
+		return -4;
+	}
+
+	return WEXITSTATUS(status);
+}
diff --git a/tools/testing/selftests/riscv/vector/v_helpers.h b/tools/testing/selftests/riscv/vector/v_helpers.h
new file mode 100644
index 000000000000..88719c4be496
--- /dev/null
+++ b/tools/testing/selftests/riscv/vector/v_helpers.h
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+int is_vector_supported(void);
+
+int launch_test(char *next_program, int test_inherit);
diff --git a/tools/testing/selftests/riscv/vector/v_initval.c b/tools/testing/selftests/riscv/vector/v_initval.c
new file mode 100644
index 000000000000..f38b5797fa31
--- /dev/null
+++ b/tools/testing/selftests/riscv/vector/v_initval.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "../../kselftest_harness.h"
+#include "v_helpers.h"
+
+#define NEXT_PROGRAM "./v_exec_initval_nolibc"
+
+TEST(v_initval)
+{
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
+
+	ASSERT_EQ(0, launch_test(NEXT_PROGRAM, 0));
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/riscv/vector/v_initval_nolibc.c b/tools/testing/selftests/riscv/vector/v_initval_nolibc.c
deleted file mode 100644
index 1dd94197da30..000000000000
--- a/tools/testing/selftests/riscv/vector/v_initval_nolibc.c
+++ /dev/null
@@ -1,68 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-
-#include "../../kselftest.h"
-#define MAX_VSIZE	(8192 * 32)
-
-void dump(char *ptr, int size)
-{
-	int i = 0;
-
-	for (i = 0; i < size; i++) {
-		if (i != 0) {
-			if (i % 16 == 0)
-				printf("\n");
-			else if (i % 8 == 0)
-				printf("  ");
-		}
-		printf("%02x ", ptr[i]);
-	}
-	printf("\n");
-}
-
-int main(void)
-{
-	int i;
-	unsigned long vl;
-	char *datap, *tmp;
-
-	datap = malloc(MAX_VSIZE);
-	if (!datap) {
-		ksft_test_result_fail("fail to allocate memory for size = %d\n", MAX_VSIZE);
-		exit(-1);
-	}
-
-	tmp = datap;
-	asm volatile (
-		".option push\n\t"
-		".option arch, +v\n\t"
-		"vsetvli	%0, x0, e8, m8, ta, ma\n\t"
-		"vse8.v		v0, (%2)\n\t"
-		"add		%1, %2, %0\n\t"
-		"vse8.v		v8, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vse8.v		v16, (%1)\n\t"
-		"add		%1, %1, %0\n\t"
-		"vse8.v		v24, (%1)\n\t"
-		".option pop\n\t"
-		: "=&r" (vl), "=r" (tmp) : "r" (datap) : "memory");
-
-	ksft_print_msg("vl = %lu\n", vl);
-
-	if (datap[0] != 0x00 && datap[0] != 0xff) {
-		ksft_test_result_fail("v-regesters are not properly initialized\n");
-		dump(datap, vl * 4);
-		exit(-1);
-	}
-
-	for (i = 1; i < vl * 4; i++) {
-		if (datap[i] != datap[0]) {
-			ksft_test_result_fail("detect stale values on v-regesters\n");
-			dump(datap, vl * 4);
-			exit(-2);
-		}
-	}
-
-	free(datap);
-	ksft_exit_pass();
-	return 0;
-}
diff --git a/tools/testing/selftests/riscv/vector/vstate_prctl.c b/tools/testing/selftests/riscv/vector/vstate_prctl.c
index 27668fb3b6d0..528e8c544db0 100644
--- a/tools/testing/selftests/riscv/vector/vstate_prctl.c
+++ b/tools/testing/selftests/riscv/vector/vstate_prctl.c
@@ -3,50 +3,13 @@
 #include <unistd.h>
 #include <errno.h>
 #include <sys/wait.h>
+#include <sys/types.h>
+#include <stdlib.h>
 
-#include "../hwprobe/hwprobe.h"
-#include "../../kselftest.h"
+#include "../../kselftest_harness.h"
+#include "v_helpers.h"
 
 #define NEXT_PROGRAM "./vstate_exec_nolibc"
-static int launch_test(int test_inherit)
-{
-	char *exec_argv[3], *exec_envp[1];
-	int rc, pid, status;
-
-	pid = fork();
-	if (pid < 0) {
-		ksft_test_result_fail("fork failed %d", pid);
-		return -1;
-	}
-
-	if (!pid) {
-		exec_argv[0] = NEXT_PROGRAM;
-		exec_argv[1] = test_inherit != 0 ? "x" : NULL;
-		exec_argv[2] = NULL;
-		exec_envp[0] = NULL;
-		/* launch the program again to check inherit */
-		rc = execve(NEXT_PROGRAM, exec_argv, exec_envp);
-		if (rc) {
-			perror("execve");
-			ksft_test_result_fail("child execve failed %d\n", rc);
-			exit(-1);
-		}
-	}
-
-	rc = waitpid(-1, &status, 0);
-	if (rc < 0) {
-		ksft_test_result_fail("waitpid failed\n");
-		return -3;
-	}
-
-	if ((WIFEXITED(status) && WEXITSTATUS(status) == -1) ||
-	    WIFSIGNALED(status)) {
-		ksft_test_result_fail("child exited abnormally\n");
-		return -4;
-	}
-
-	return WEXITSTATUS(status);
-}
 
 int test_and_compare_child(long provided, long expected, int inherit)
 {
@@ -54,14 +17,13 @@ int test_and_compare_child(long provided, long expected, int inherit)
 
 	rc = prctl(PR_RISCV_V_SET_CONTROL, provided);
 	if (rc != 0) {
-		ksft_test_result_fail("prctl with provided arg %lx failed with code %d\n",
-				      provided, rc);
+		printf("prctl with provided arg %lx failed with code %d\n",
+		       provided, rc);
 		return -1;
 	}
-	rc = launch_test(inherit);
+	rc = launch_test(NEXT_PROGRAM, inherit);
 	if (rc != expected) {
-		ksft_test_result_fail("Test failed, check %d != %ld\n", rc,
-				      expected);
+		printf("Test failed, check %d != %ld\n", rc,  expected);
 		return -2;
 	}
 	return 0;
@@ -70,112 +32,180 @@ int test_and_compare_child(long provided, long expected, int inherit)
 #define PR_RISCV_V_VSTATE_CTRL_CUR_SHIFT	0
 #define PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT	2
 
-int main(void)
+TEST(get_control_no_v)
 {
-	struct riscv_hwprobe pair;
-	long flag, expected;
 	long rc;
 
-	pair.key = RISCV_HWPROBE_KEY_IMA_EXT_0;
-	rc = riscv_hwprobe(&pair, 1, 0, NULL, 0);
-	if (rc < 0) {
-		ksft_test_result_fail("hwprobe() failed with %ld\n", rc);
-		return -1;
-	}
+	if (is_vector_supported())
+		SKIP(return, "Test expects vector to be not supported");
 
-	if (pair.key != RISCV_HWPROBE_KEY_IMA_EXT_0) {
-		ksft_test_result_fail("hwprobe cannot probe RISCV_HWPROBE_KEY_IMA_EXT_0\n");
-		return -2;
-	}
+	rc = prctl(PR_RISCV_V_GET_CONTROL);
+	EXPECT_EQ(-1, rc) TH_LOG("GET_CONTROL should fail on kernel/hw without V");
+	EXPECT_EQ(EINVAL, errno) TH_LOG("GET_CONTROL should fail on kernel/hw without V");
+}
 
-	if (!(pair.value & RISCV_HWPROBE_IMA_V)) {
-		rc = prctl(PR_RISCV_V_GET_CONTROL);
-		if (rc != -1 || errno != EINVAL) {
-			ksft_test_result_fail("GET_CONTROL should fail on kernel/hw without V\n");
-			return -3;
-		}
-
-		rc = prctl(PR_RISCV_V_SET_CONTROL, PR_RISCV_V_VSTATE_CTRL_ON);
-		if (rc != -1 || errno != EINVAL) {
-			ksft_test_result_fail("GET_CONTROL should fail on kernel/hw without V\n");
-			return -4;
-		}
-
-		ksft_test_result_skip("Vector not supported\n");
-		return 0;
-	}
+TEST(set_control_no_v)
+{
+	long rc;
+
+	if (is_vector_supported())
+		SKIP(return, "Test expects vector to be not supported");
+
+	rc = prctl(PR_RISCV_V_SET_CONTROL, PR_RISCV_V_VSTATE_CTRL_ON);
+	EXPECT_EQ(-1, rc) TH_LOG("SET_CONTROL should fail on kernel/hw without V");
+	EXPECT_EQ(EINVAL, errno) TH_LOG("SET_CONTROL should fail on kernel/hw without V");
+}
+
+TEST(vstate_on_current)
+{
+	long flag;
+	long rc;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
 	flag = PR_RISCV_V_VSTATE_CTRL_ON;
 	rc = prctl(PR_RISCV_V_SET_CONTROL, flag);
-	if (rc != 0) {
-		ksft_test_result_fail("Enabling V for current should always success\n");
-		return -5;
-	}
+	EXPECT_EQ(0, rc) TH_LOG("Enabling V for current should always success");
+}
+
+TEST(vstate_off_eperm)
+{
+	long flag;
+	long rc;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
 	flag = PR_RISCV_V_VSTATE_CTRL_OFF;
 	rc = prctl(PR_RISCV_V_SET_CONTROL, flag);
-	if (rc != -1 || errno != EPERM) {
-		ksft_test_result_fail("Disabling current's V alive must fail with EPERM(%d)\n",
-				      errno);
-		return -5;
-	}
+	EXPECT_EQ(EPERM, errno) TH_LOG("Disabling current's V alive must fail with EPERM(%d)", errno);
+	EXPECT_EQ(-1, rc) TH_LOG("Disabling current's V alive must fail with EPERM(%d)", errno);
+}
+
+TEST(vstate_on_no_nesting)
+{
+	long flag;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
 	/* Turn on next's vector explicitly and test */
 	flag = PR_RISCV_V_VSTATE_CTRL_ON << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
-	if (test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_ON, 0))
-		return -6;
+
+	EXPECT_EQ(0, test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_ON, 0));
+}
+
+TEST(vstate_off_nesting)
+{
+	long flag;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
 	/* Turn off next's vector explicitly and test */
 	flag = PR_RISCV_V_VSTATE_CTRL_OFF << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
-	if (test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_OFF, 0))
-		return -7;
+
+	EXPECT_EQ(0, test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_OFF, 1));
+}
+
+TEST(vstate_on_inherit_no_nesting)
+{
+	long flag, expected;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
+
+	/* Turn on next's vector explicitly and test no inherit */
+	flag = PR_RISCV_V_VSTATE_CTRL_ON << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
+	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
+	expected = flag | PR_RISCV_V_VSTATE_CTRL_ON;
+
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 0));
+}
+
+TEST(vstate_on_inherit)
+{
+	long flag, expected;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
 	/* Turn on next's vector explicitly and test inherit */
 	flag = PR_RISCV_V_VSTATE_CTRL_ON << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
 	expected = flag | PR_RISCV_V_VSTATE_CTRL_ON;
-	if (test_and_compare_child(flag, expected, 0))
-		return -8;
 
-	if (test_and_compare_child(flag, expected, 1))
-		return -9;
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 1));
+}
+
+TEST(vstate_off_inherit_no_nesting)
+{
+	long flag, expected;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
+
+	/* Turn off next's vector explicitly and test no inherit */
+	flag = PR_RISCV_V_VSTATE_CTRL_OFF << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
+	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
+	expected = flag | PR_RISCV_V_VSTATE_CTRL_OFF;
+
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 0));
+}
+
+TEST(vstate_off_inherit)
+{
+	long flag, expected;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
 	/* Turn off next's vector explicitly and test inherit */
 	flag = PR_RISCV_V_VSTATE_CTRL_OFF << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
 	expected = flag | PR_RISCV_V_VSTATE_CTRL_OFF;
-	if (test_and_compare_child(flag, expected, 0))
-		return -10;
 
-	if (test_and_compare_child(flag, expected, 1))
-		return -11;
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 1));
+}
+
+/* arguments should fail with EINVAL */
+TEST(inval_set_control_1)
+{
+	int rc;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
-	/* arguments should fail with EINVAL */
 	rc = prctl(PR_RISCV_V_SET_CONTROL, 0xff0);
-	if (rc != -1 || errno != EINVAL) {
-		ksft_test_result_fail("Undefined control argument should return EINVAL\n");
-		return -12;
-	}
+	EXPECT_EQ(-1, rc);
+	EXPECT_EQ(EINVAL, errno);
+}
+
+/* arguments should fail with EINVAL */
+TEST(inval_set_control_2)
+{
+	int rc;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
 	rc = prctl(PR_RISCV_V_SET_CONTROL, 0x3);
-	if (rc != -1 || errno != EINVAL) {
-		ksft_test_result_fail("Undefined control argument should return EINVAL\n");
-		return -12;
-	}
+	EXPECT_EQ(-1, rc);
+	EXPECT_EQ(EINVAL, errno);
+}
 
-	rc = prctl(PR_RISCV_V_SET_CONTROL, 0xc);
-	if (rc != -1 || errno != EINVAL) {
-		ksft_test_result_fail("Undefined control argument should return EINVAL\n");
-		return -12;
-	}
+/* arguments should fail with EINVAL */
+TEST(inval_set_control_3)
+{
+	int rc;
 
-	rc = prctl(PR_RISCV_V_SET_CONTROL, 0xc);
-	if (rc != -1 || errno != EINVAL) {
-		ksft_test_result_fail("Undefined control argument should return EINVAL\n");
-		return -12;
-	}
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
 
-	ksft_test_result_pass("tests for riscv_v_vstate_ctrl pass\n");
-	ksft_exit_pass();
-	return 0;
+	rc = prctl(PR_RISCV_V_SET_CONTROL, 0xc);
+	EXPECT_EQ(-1, rc);
+	EXPECT_EQ(EINVAL, errno);
 }
+
+TEST_HARNESS_MAIN

-- 
2.44.0

[PATCH v5 17/17] selftests: riscv: Support xtheadvector in vector tests

[Charlie Jenkins]

Extend existing vector tests to be compatible with the xtheadvector
instruction set.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 .../selftests/riscv/vector/v_exec_initval_nolibc.c | 23 ++++--
 tools/testing/selftests/riscv/vector/v_helpers.c   | 17 +++-
 tools/testing/selftests/riscv/vector/v_helpers.h   |  4 +-
 tools/testing/selftests/riscv/vector/v_initval.c   | 12 ++-
 .../selftests/riscv/vector/vstate_exec_nolibc.c    | 20 +++--
 .../testing/selftests/riscv/vector/vstate_prctl.c  | 91 ++++++++++++++--------
 6 files changed, 115 insertions(+), 52 deletions(-)

diff --git a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
index 74b13806baf0..58c29ea91b80 100644
--- a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
+++ b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
@@ -18,13 +18,22 @@ int main(int argc, char **argv)
 	unsigned long vl;
 	int first = 1;
 
-	asm volatile (
-		".option push\n\t"
-		".option arch, +v\n\t"
-		"vsetvli	%[vl], x0, e8, m1, ta, ma\n\t"
-		".option pop\n\t"
-		: [vl] "=r" (vl)
-	);
+	if (argc > 2 && strcmp(argv[2], "x"))
+		asm volatile (
+			// 0 | zimm[10:0] | rs1 | 1 1 1 | rd |1010111| vsetvli
+			// vsetvli	t4, x0, e8, m1, d1
+			".insn		0b00000000000000000111111011010111\n\t"
+			"mv		%[vl], t4\n\t"
+			: [vl] "=r" (vl) : : "t4"
+		);
+	else
+		asm volatile (
+			".option push\n\t"
+			".option arch, +v\n\t"
+			"vsetvli	%[vl], x0, e8, m1, ta, ma\n\t"
+			".option pop\n\t"
+			: [vl] "=r" (vl)
+		);
 
 #define CHECK_VECTOR_REGISTER(register) ({					\
 	for (int i = 0; i < vl; i++) {						\
diff --git a/tools/testing/selftests/riscv/vector/v_helpers.c b/tools/testing/selftests/riscv/vector/v_helpers.c
index 15c22318db72..2c4df76eefe9 100644
--- a/tools/testing/selftests/riscv/vector/v_helpers.c
+++ b/tools/testing/selftests/riscv/vector/v_helpers.c
@@ -1,11 +1,21 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
 #include "../hwprobe/hwprobe.h"
+#include <asm/vendor/thead.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/wait.h>
 
+int is_xtheadvector_supported(void)
+{
+	struct riscv_hwprobe pair;
+
+	pair.key = RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0;
+	riscv_hwprobe(&pair, 1, 0, NULL, 0);
+	return pair.value & RISCV_HWPROBE_VENDOR_EXT_XTHEADVECTOR;
+}
+
 int is_vector_supported(void)
 {
 	struct riscv_hwprobe pair;
@@ -15,9 +25,9 @@ int is_vector_supported(void)
 	return pair.value & RISCV_HWPROBE_IMA_V;
 }
 
-int launch_test(char *next_program, int test_inherit)
+int launch_test(char *next_program, int test_inherit, int xtheadvector)
 {
-	char *exec_argv[3], *exec_envp[1];
+	char *exec_argv[4], *exec_envp[1];
 	int rc, pid, status;
 
 	pid = fork();
@@ -29,7 +39,8 @@ int launch_test(char *next_program, int test_inherit)
 	if (!pid) {
 		exec_argv[0] = next_program;
 		exec_argv[1] = test_inherit != 0 ? "x" : NULL;
-		exec_argv[2] = NULL;
+		exec_argv[2] = xtheadvector != 0 ? "x" : NULL;
+		exec_argv[3] = NULL;
 		exec_envp[0] = NULL;
 		/* launch the program again to check inherit */
 		rc = execve(next_program, exec_argv, exec_envp);
diff --git a/tools/testing/selftests/riscv/vector/v_helpers.h b/tools/testing/selftests/riscv/vector/v_helpers.h
index 88719c4be496..67d41cb6f871 100644
--- a/tools/testing/selftests/riscv/vector/v_helpers.h
+++ b/tools/testing/selftests/riscv/vector/v_helpers.h
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+int is_xtheadvector_supported(void);
+
 int is_vector_supported(void);
 
-int launch_test(char *next_program, int test_inherit);
+int launch_test(char *next_program, int test_inherit, int xtheadvector);
diff --git a/tools/testing/selftests/riscv/vector/v_initval.c b/tools/testing/selftests/riscv/vector/v_initval.c
index f38b5797fa31..be9e1d18ad29 100644
--- a/tools/testing/selftests/riscv/vector/v_initval.c
+++ b/tools/testing/selftests/riscv/vector/v_initval.c
@@ -7,10 +7,16 @@
 
 TEST(v_initval)
 {
-	if (!is_vector_supported())
-		SKIP(return, "Vector not supported");
+	int xtheadvector = 0;
 
-	ASSERT_EQ(0, launch_test(NEXT_PROGRAM, 0));
+	if (!is_vector_supported()) {
+		if (is_xtheadvector_supported())
+			xtheadvector = 1;
+		else
+			SKIP(return, "Vector not supported");
+	}
+
+	ASSERT_EQ(0, launch_test(NEXT_PROGRAM, 0, xtheadvector));
 }
 
 TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/riscv/vector/vstate_exec_nolibc.c b/tools/testing/selftests/riscv/vector/vstate_exec_nolibc.c
index 1f9969bed235..12d30d3b90fa 100644
--- a/tools/testing/selftests/riscv/vector/vstate_exec_nolibc.c
+++ b/tools/testing/selftests/riscv/vector/vstate_exec_nolibc.c
@@ -6,13 +6,16 @@
 
 int main(int argc, char **argv)
 {
-	int rc, pid, status, test_inherit = 0;
+	int rc, pid, status, test_inherit = 0, xtheadvector = 0;
 	long ctrl, ctrl_c;
 	char *exec_argv[2], *exec_envp[2];
 
-	if (argc > 1)
+	if (argc > 1 && strcmp(argv[1], "x"))
 		test_inherit = 1;
 
+	if (argc > 2 && strcmp(argv[2], "x"))
+		xtheadvector = 1;
+
 	ctrl = my_syscall1(__NR_prctl, PR_RISCV_V_GET_CONTROL);
 	if (ctrl < 0) {
 		puts("PR_RISCV_V_GET_CONTROL is not supported\n");
@@ -53,11 +56,14 @@ int main(int argc, char **argv)
 				puts("child's vstate_ctrl not equal to parent's\n");
 				exit(-1);
 			}
-			asm volatile (".option push\n\t"
-				      ".option arch, +v\n\t"
-				      "vsetvli x0, x0, e32, m8, ta, ma\n\t"
-				      ".option pop\n\t"
-				      );
+			if (xtheadvector)
+				asm volatile (".insn	0x00007ed7");
+			else
+				asm volatile (".option push\n\t"
+					".option arch, +v\n\t"
+					"vsetvli x0, x0, e32, m8, ta, ma\n\t"
+					".option pop\n\t"
+					);
 			exit(ctrl);
 		}
 	}
diff --git a/tools/testing/selftests/riscv/vector/vstate_prctl.c b/tools/testing/selftests/riscv/vector/vstate_prctl.c
index 528e8c544db0..375af40e88e6 100644
--- a/tools/testing/selftests/riscv/vector/vstate_prctl.c
+++ b/tools/testing/selftests/riscv/vector/vstate_prctl.c
@@ -11,7 +11,7 @@
 
 #define NEXT_PROGRAM "./vstate_exec_nolibc"
 
-int test_and_compare_child(long provided, long expected, int inherit)
+int test_and_compare_child(long provided, long expected, int inherit, int xtheadvector)
 {
 	int rc;
 
@@ -21,7 +21,7 @@ int test_and_compare_child(long provided, long expected, int inherit)
 		       provided, rc);
 		return -1;
 	}
-	rc = launch_test(NEXT_PROGRAM, inherit);
+	rc = launch_test(NEXT_PROGRAM, inherit, xtheadvector);
 	if (rc != expected) {
 		printf("Test failed, check %d != %ld\n", rc,  expected);
 		return -2;
@@ -36,7 +36,7 @@ TEST(get_control_no_v)
 {
 	long rc;
 
-	if (is_vector_supported())
+	if (is_vector_supported() || is_xtheadvector_supported())
 		SKIP(return, "Test expects vector to be not supported");
 
 	rc = prctl(PR_RISCV_V_GET_CONTROL);
@@ -48,7 +48,7 @@ TEST(set_control_no_v)
 {
 	long rc;
 
-	if (is_vector_supported())
+	if (is_vector_supported() || is_xtheadvector_supported())
 		SKIP(return, "Test expects vector to be not supported");
 
 	rc = prctl(PR_RISCV_V_SET_CONTROL, PR_RISCV_V_VSTATE_CTRL_ON);
@@ -61,12 +61,12 @@ TEST(vstate_on_current)
 	long flag;
 	long rc;
 
-	if (!is_vector_supported())
+	if (!is_vector_supported() && !is_xtheadvector_supported())
 		SKIP(return, "Vector not supported");
 
 	flag = PR_RISCV_V_VSTATE_CTRL_ON;
 	rc = prctl(PR_RISCV_V_SET_CONTROL, flag);
-	EXPECT_EQ(0, rc) TH_LOG("Enabling V for current should always success");
+	EXPECT_EQ(0, rc) TH_LOG("Enabling V for current should always succeed");
 }
 
 TEST(vstate_off_eperm)
@@ -74,99 +74,128 @@ TEST(vstate_off_eperm)
 	long flag;
 	long rc;
 
-	if (!is_vector_supported())
+	if (!is_vector_supported() && !is_xtheadvector_supported())
 		SKIP(return, "Vector not supported");
 
 	flag = PR_RISCV_V_VSTATE_CTRL_OFF;
 	rc = prctl(PR_RISCV_V_SET_CONTROL, flag);
-	EXPECT_EQ(EPERM, errno) TH_LOG("Disabling current's V alive must fail with EPERM(%d)", errno);
-	EXPECT_EQ(-1, rc) TH_LOG("Disabling current's V alive must fail with EPERM(%d)", errno);
+	EXPECT_EQ(EPERM, errno) TH_LOG("Disabling V in current thread with V enabled must fail with EPERM(%d)", errno);
+	EXPECT_EQ(-1, rc) TH_LOG("Disabling V in current thread with V enabled must fail with EPERM(%d)", errno);
 }
 
 TEST(vstate_on_no_nesting)
 {
 	long flag;
+	int xtheadvector = 0;
 
-	if (!is_vector_supported())
-		SKIP(return, "Vector not supported");
+	if (!is_vector_supported()) {
+		if (is_xtheadvector_supported())
+			xtheadvector = 1;
+		else
+			SKIP(return, "Vector not supported");
+	}
 
 	/* Turn on next's vector explicitly and test */
 	flag = PR_RISCV_V_VSTATE_CTRL_ON << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 
-	EXPECT_EQ(0, test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_ON, 0));
+	EXPECT_EQ(0, test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_ON, 0, xtheadvector));
 }
 
 TEST(vstate_off_nesting)
 {
 	long flag;
+	int xtheadvector = 0;
 
-	if (!is_vector_supported())
-		SKIP(return, "Vector not supported");
+	if (!is_vector_supported()) {
+		if (is_xtheadvector_supported())
+			xtheadvector = 1;
+		else
+			SKIP(return, "Vector not supported");
+	}
 
 	/* Turn off next's vector explicitly and test */
 	flag = PR_RISCV_V_VSTATE_CTRL_OFF << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 
-	EXPECT_EQ(0, test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_OFF, 1));
+	EXPECT_EQ(0, test_and_compare_child(flag, PR_RISCV_V_VSTATE_CTRL_OFF, 1, xtheadvector));
 }
 
 TEST(vstate_on_inherit_no_nesting)
 {
 	long flag, expected;
+	int xtheadvector = 0;
 
-	if (!is_vector_supported())
-		SKIP(return, "Vector not supported");
+	if (!is_vector_supported()) {
+		if (is_xtheadvector_supported())
+			xtheadvector = 1;
+		else
+			SKIP(return, "Vector not supported");
+	}
 
 	/* Turn on next's vector explicitly and test no inherit */
 	flag = PR_RISCV_V_VSTATE_CTRL_ON << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
 	expected = flag | PR_RISCV_V_VSTATE_CTRL_ON;
 
-	EXPECT_EQ(0, test_and_compare_child(flag, expected, 0));
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 0, xtheadvector));
 }
 
 TEST(vstate_on_inherit)
 {
 	long flag, expected;
+	int xtheadvector = 0;
 
-	if (!is_vector_supported())
-		SKIP(return, "Vector not supported");
+	if (!is_vector_supported()) {
+		if (is_xtheadvector_supported())
+			xtheadvector = 1;
+		else
+			SKIP(return, "Vector not supported");
+	}
 
 	/* Turn on next's vector explicitly and test inherit */
 	flag = PR_RISCV_V_VSTATE_CTRL_ON << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
 	expected = flag | PR_RISCV_V_VSTATE_CTRL_ON;
 
-	EXPECT_EQ(0, test_and_compare_child(flag, expected, 1));
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 1, xtheadvector));
 }
 
 TEST(vstate_off_inherit_no_nesting)
 {
 	long flag, expected;
+	int xtheadvector = 0;
 
-	if (!is_vector_supported())
-		SKIP(return, "Vector not supported");
-
+	if (!is_vector_supported()) {
+		if (is_xtheadvector_supported())
+			xtheadvector = 1;
+		else
+			SKIP(return, "Vector not supported");
+	}
 	/* Turn off next's vector explicitly and test no inherit */
 	flag = PR_RISCV_V_VSTATE_CTRL_OFF << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
 	expected = flag | PR_RISCV_V_VSTATE_CTRL_OFF;
 
-	EXPECT_EQ(0, test_and_compare_child(flag, expected, 0));
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 0, xtheadvector));
 }
 
 TEST(vstate_off_inherit)
 {
 	long flag, expected;
+	int xtheadvector = 0;
 
-	if (!is_vector_supported())
-		SKIP(return, "Vector not supported");
+	if (!is_vector_supported()) {
+		if (is_xtheadvector_supported())
+			xtheadvector = 1;
+		else
+			SKIP(return, "Vector not supported");
+	}
 
 	/* Turn off next's vector explicitly and test inherit */
 	flag = PR_RISCV_V_VSTATE_CTRL_OFF << PR_RISCV_V_VSTATE_CTRL_NEXT_SHIFT;
 	flag |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
 	expected = flag | PR_RISCV_V_VSTATE_CTRL_OFF;
 
-	EXPECT_EQ(0, test_and_compare_child(flag, expected, 1));
+	EXPECT_EQ(0, test_and_compare_child(flag, expected, 1, xtheadvector));
 }
 
 /* arguments should fail with EINVAL */
@@ -174,7 +203,7 @@ TEST(inval_set_control_1)
 {
 	int rc;
 
-	if (!is_vector_supported())
+	if (!is_vector_supported() && !is_xtheadvector_supported())
 		SKIP(return, "Vector not supported");
 
 	rc = prctl(PR_RISCV_V_SET_CONTROL, 0xff0);
@@ -187,7 +216,7 @@ TEST(inval_set_control_2)
 {
 	int rc;
 
-	if (!is_vector_supported())
+	if (!is_vector_supported() && !is_xtheadvector_supported())
 		SKIP(return, "Vector not supported");
 
 	rc = prctl(PR_RISCV_V_SET_CONTROL, 0x3);
@@ -200,7 +229,7 @@ TEST(inval_set_control_3)
 {
 	int rc;
 
-	if (!is_vector_supported())
+	if (!is_vector_supported() && !is_xtheadvector_supported())
 		SKIP(return, "Vector not supported");
 
 	rc = prctl(PR_RISCV_V_SET_CONTROL, 0xc);

-- 
2.44.0

Re: [PATCH v5 05/17] riscv: Extend cpufeature.c to detect vendor extensions

[Evan Green]

On Thu, May 2, 2024 at 9:46 PM Charlie Jenkins <charlie@rivosinc.com> wrote:
>
> Separate vendor extensions out into one struct per vendor
> instead of adding vendor extensions onto riscv_isa_ext.
>
> Add a hidden config RISCV_ISA_VENDOR_EXT to conditionally include this
> code.
>
> The xtheadvector vendor extension is added using these changes.
>
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> ---
>  arch/riscv/Kconfig                               |  2 +
>  arch/riscv/Kconfig.vendor                        | 19 +++++
>  arch/riscv/include/asm/cpufeature.h              | 18 +++++
>  arch/riscv/include/asm/vendor_extensions.h       | 34 +++++++++
>  arch/riscv/include/asm/vendor_extensions/thead.h | 16 ++++
>  arch/riscv/kernel/Makefile                       |  2 +
>  arch/riscv/kernel/cpufeature.c                   | 93 +++++++++++++++++++-----
>  arch/riscv/kernel/vendor_extensions.c            | 18 +++++
>  arch/riscv/kernel/vendor_extensions/Makefile     |  3 +
>  arch/riscv/kernel/vendor_extensions/thead.c      | 18 +++++
>  10 files changed, 203 insertions(+), 20 deletions(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index be09c8836d56..fec86fba3acd 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -759,6 +759,8 @@ config RISCV_EFFICIENT_UNALIGNED_ACCESS
>
>  endchoice
>
> +source "arch/riscv/Kconfig.vendor"
> +
>  endmenu # "Platform type"
>
>  menu "Kernel features"
> diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor
> new file mode 100644
> index 000000000000..85ac30496b0e
> --- /dev/null
> +++ b/arch/riscv/Kconfig.vendor
> @@ -0,0 +1,19 @@
> +menu "Vendor extensions"
> +
> +config RISCV_ISA_VENDOR_EXT
> +       bool
> +
> +menu "T-Head"
> +config RISCV_ISA_VENDOR_EXT_THEAD
> +       bool "T-Head vendor extension support"
> +       select RISCV_ISA_VENDOR_EXT
> +       default y
> +       help
> +         Say N here to disable detection of and support for all T-Head vendor
> +         extensions. Without this option enabled, T-Head vendor extensions will
> +         not be detected at boot and their presence not reported to userspace.
> +
> +         If you don't know what to do here, say Y.
> +endmenu
> +
> +endmenu
> diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> index 0c4f08577015..fedd479ccfd1 100644
> --- a/arch/riscv/include/asm/cpufeature.h
> +++ b/arch/riscv/include/asm/cpufeature.h
> @@ -35,6 +35,24 @@ extern u32 riscv_vlenb_of;
>
>  void riscv_user_isa_enable(void);
>
> +#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> +       .name = #_name,                                                         \
> +       .property = #_name,                                                     \
> +       .id = _id,                                                              \
> +       .subset_ext_ids = _subset_exts,                                         \
> +       .subset_ext_size = _subset_exts_size                                    \
> +}
> +
> +#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> +
> +/* Used to declare pure "lasso" extension (Zk for instance) */
> +#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> +       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> +
> +/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> +#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> +       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> +
>  #if defined(CONFIG_RISCV_MISALIGNED)
>  bool check_unaligned_access_emulated_all_cpus(void);
>  void unaligned_emulation_finish(void);
> diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
> new file mode 100644
> index 000000000000..bf4dac66e6e6
> --- /dev/null
> +++ b/arch/riscv/include/asm/vendor_extensions.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright 2024 Rivos, Inc
> + */
> +
> +#ifndef _ASM_VENDOR_EXTENSIONS_H
> +#define _ASM_VENDOR_EXTENSIONS_H
> +
> +#include <asm/cpufeature.h>
> +
> +#include <linux/array_size.h>
> +#include <linux/types.h>
> +
> +/*
> + * The extension keys of each vendor must be strictly less than this value.
> + */
> +#define RISCV_ISA_VENDOR_EXT_MAX 32
> +
> +struct riscv_isavendorinfo {
> +       DECLARE_BITMAP(isa, RISCV_ISA_VENDOR_EXT_MAX);
> +};

Nice, I think this was a good compromise: being honest with the
compiler about the fixed array sizes, with the tradeoff that all
vendors have to use the same ceiling for the number of bits. If one
vendor raises this ceiling absurdly and starts creating huge amounts
of waste we can revisit.

> +
> +struct riscv_isa_vendor_ext_data_list {
> +       const size_t ext_data_count;
> +       const struct riscv_isa_ext_data *ext_data;
> +       struct riscv_isavendorinfo per_hart_isa_bitmap[NR_CPUS];
> +       struct riscv_isavendorinfo all_harts_isa_bitmap;
> +};
> +
> +extern struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[];
> +
> +extern const size_t riscv_isa_vendor_ext_list_size;
> +
> +#endif /* _ASM_VENDOR_EXTENSIONS_H */
> diff --git a/arch/riscv/include/asm/vendor_extensions/thead.h b/arch/riscv/include/asm/vendor_extensions/thead.h
> new file mode 100644
> index 000000000000..48421d1553ad
> --- /dev/null
> +++ b/arch/riscv/include/asm/vendor_extensions/thead.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> +#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> +
> +#include <asm/vendor_extensions.h>
> +
> +#include <linux/types.h>
> +
> +/*
> + * Extension keys must be strictly less than RISCV_ISA_VENDOR_EXT_MAX.
> + */
> +#define RISCV_ISA_VENDOR_EXT_XTHEADVECTOR              0
> +
> +extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead;
> +
> +#endif
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index 81d94a8ee10f..53361c50fb46 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -58,6 +58,8 @@ obj-y += riscv_ksyms.o
>  obj-y  += stacktrace.o
>  obj-y  += cacheinfo.o
>  obj-y  += patch.o
> +obj-y  += vendor_extensions.o
> +obj-y  += vendor_extensions/
>  obj-y  += probes/
>  obj-y  += tests/
>  obj-$(CONFIG_MMU) += vdso.o vdso/
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 12c79db0b0bb..cc9ec393c8f6 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -24,6 +24,7 @@
>  #include <asm/processor.h>
>  #include <asm/sbi.h>
>  #include <asm/vector.h>
> +#include <asm/vendor_extensions.h>
>
>  #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
>
> @@ -102,24 +103,6 @@ static bool riscv_isa_extension_check(int id)
>         return true;
>  }
>
> -#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> -       .name = #_name,                                                         \
> -       .property = #_name,                                                     \
> -       .id = _id,                                                              \
> -       .subset_ext_ids = _subset_exts,                                         \
> -       .subset_ext_size = _subset_exts_size                                    \
> -}
> -
> -#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> -
> -/* Used to declare pure "lasso" extension (Zk for instance) */
> -#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> -       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> -
> -/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> -#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> -       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> -
>  static const unsigned int riscv_zk_bundled_exts[] = {
>         RISCV_ISA_EXT_ZBKB,
>         RISCV_ISA_EXT_ZBKC,
> @@ -353,6 +336,21 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
>                 bool ext_long = false, ext_err = false;
>
>                 switch (*ext) {
> +               case 'x':
> +               case 'X':
> +                       if (acpi_disabled)
> +                               pr_warn_once("Vendor extensions are ignored in riscv,isa. Use riscv,isa-extensions instead.");
> +                       /*
> +                        * To skip an extension, we find its end.
> +                        * As multi-letter extensions must be split from other multi-letter
> +                        * extensions with an "_", the end of a multi-letter extension will
> +                        * either be the null character or the "_" at the start of the next
> +                        * multi-letter extension.
> +                        */
> +                       for (; *isa && *isa != '_'; ++isa)
> +                               ;
> +                       ext_err = true;
> +                       break;
>                 case 's':
>                         /*
>                          * Workaround for invalid single-letter 's' & 'u' (QEMU).
> @@ -368,8 +366,6 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
>                         }
>                         fallthrough;
>                 case 'S':
> -               case 'x':
> -               case 'X':
>                 case 'z':
>                 case 'Z':
>                         /*
> @@ -572,6 +568,59 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
>                 acpi_put_table((struct acpi_table_header *)rhct);
>  }
>
> +static void __init riscv_fill_cpu_vendor_ext(struct device_node *cpu_node, int cpu)
> +{
> +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> +               return;
> +
> +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> +
> +               for (int j = 0; j < ext_list->ext_data_count; j++) {
> +                       const struct riscv_isa_ext_data ext = ext_list->ext_data[j];
> +                       struct riscv_isavendorinfo *isavendorinfo = &ext_list->per_hart_isa_bitmap[cpu];
> +
> +                       if (of_property_match_string(cpu_node, "riscv,isa-extensions",
> +                                                    ext.property) < 0)
> +                               continue;
> +
> +                       /*
> +                        * Assume that subset extensions are all members of the
> +                        * same vendor.
> +                        */
> +                       if (ext.subset_ext_size)
> +                               for (int k = 0; k < ext.subset_ext_size; k++)
> +                                       set_bit(ext.subset_ext_ids[k], isavendorinfo->isa);
> +
> +                       set_bit(ext.id, isavendorinfo->isa);
> +               }
> +       }
> +}
> +
> +static void __init riscv_fill_vendor_ext_list(int cpu)
> +{
> +       bool first = true;
> +
> +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> +               return;
> +
> +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> +
> +               if (first) {
> +                       bitmap_copy(ext_list->all_harts_isa_bitmap.isa,
> +                                   ext_list->per_hart_isa_bitmap[cpu].isa,
> +                                   RISCV_ISA_VENDOR_EXT_MAX);
> +                       first = false;

I think this is still not quite right. This behaves properly when
called on the first cpu (let's say 0), but then we call it again with
cpu 1, first gets set to true, and we clobber the old work we did for
cpu 0. If we knew that cpu 0 was always called first (this looks true
since both calls are within a for_each_possible_cpu() loop), and that
this was only called once at boot for cpu 0 (looks true, and
riscv_fill_hwcap() is __init), then it could be bool first = cpu == 0.

Re: [PATCH v5 14/17] riscv: hwprobe: Add thead vendor extension probing

[Evan Green]

On Thu, May 2, 2024 at 9:47 PM Charlie Jenkins <charlie@rivosinc.com> wrote:
>
> Add a new hwprobe key "RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0" which
> allows userspace to probe for the new RISCV_ISA_VENDOR_EXT_XTHEADVECTOR
> vendor extension.
>
> This new key will allow userspace code to probe for which thead vendor
> extensions are supported. This API is modeled to be consistent with
> RISCV_HWPROBE_KEY_IMA_EXT_0. The bitmask returned will have each bit
> corresponding to a supported thead vendor extension of the cpumask set.
> Just like RISCV_HWPROBE_KEY_IMA_EXT_0, this allows a userspace program
> to determine all of the supported thead vendor extensions in one call.
>
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>

Reviewed-by: Evan Green <evan@rivosinc.com>

> ---
>  arch/riscv/include/asm/hwprobe.h                   |  4 +--
>  .../include/asm/vendor_extensions/thead_hwprobe.h  | 18 ++++++++++++
>  .../include/asm/vendor_extensions/vendor_hwprobe.h | 34 ++++++++++++++++++++++
>  arch/riscv/include/uapi/asm/hwprobe.h              |  3 +-
>  arch/riscv/include/uapi/asm/vendor/thead.h         |  3 ++
>  arch/riscv/kernel/sys_hwprobe.c                    |  5 ++++
>  arch/riscv/kernel/vendor_extensions/Makefile       |  1 +
>  .../riscv/kernel/vendor_extensions/thead_hwprobe.c | 19 ++++++++++++
>  8 files changed, 84 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> index 630507dff5ea..e68496b4f8de 100644
> --- a/arch/riscv/include/asm/hwprobe.h
> +++ b/arch/riscv/include/asm/hwprobe.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>  /*
> - * Copyright 2023 Rivos, Inc
> + * Copyright 2023-2024 Rivos, Inc
>   */
>
>  #ifndef _ASM_HWPROBE_H
> @@ -8,7 +8,7 @@
>
>  #include <uapi/asm/hwprobe.h>
>
> -#define RISCV_HWPROBE_MAX_KEY 6
> +#define RISCV_HWPROBE_MAX_KEY 7
>
>  static inline bool riscv_hwprobe_key_is_valid(__s64 key)
>  {
> diff --git a/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h b/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h
> new file mode 100644
> index 000000000000..925fef39a2c0
> --- /dev/null
> +++ b/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_HWPROBE_H
> +#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_HWPROBE_H
> +
> +#include <linux/cpumask.h>
> +
> +#include <uapi/asm/hwprobe.h>
> +
> +#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
> +void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus);
> +#else
> +static inline void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus)
> +{
> +       pair->value = 0;
> +}
> +#endif
> +
> +#endif
> diff --git a/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h b/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h
> new file mode 100644
> index 000000000000..2a29f1a5cae3
> --- /dev/null
> +++ b/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright 2024 Rivos, Inc
> + */
> +
> +#ifndef _ASM_RISCV_SYS_HWPROBE_H
> +#define _ASM_RISCV_SYS_HWPROBE_H
> +
> +#include <asm/cpufeature.h>
> +
> +#define EXT_KEY(ext)                                                                   \
> +       do {                                                                            \
> +               if (__riscv_isa_extension_available(isainfo->isa, RISCV_ISA_VENDOR_EXT_##ext)) \
> +                       pair->value |= RISCV_HWPROBE_VENDOR_EXT_##ext;                  \
> +               else                                                                    \
> +                       missing |= RISCV_HWPROBE_VENDOR_EXT_##ext;                      \
> +       } while (false)
> +
> +/*
> + * Loop through and record extensions that 1) anyone has, and 2) anyone
> + * doesn't have.
> + */
> +#define VENDOR_EXTENSION_SUPPORTED(pair, cpus, per_hart_thead_bitmap, ...)                     \
> +       do {                                                                                    \
> +               int cpu;                                                                        \
> +               u64 missing;                                                                    \
> +               for_each_cpu(cpu, (cpus)) {                                                     \
> +                       struct riscv_isavendorinfo *isainfo = &(per_hart_thead_bitmap)[cpu];    \
> +                       __VA_ARGS__                                                             \
> +               }                                                                               \
> +               (pair)->value &= ~missing;                                                      \
> +       } while (false)                                                                         \
> +
> +#endif /* _ASM_RISCV_SYS_HWPROBE_H */
> diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> index 9f2a8e3ff204..21e96a63f9ea 100644
> --- a/arch/riscv/include/uapi/asm/hwprobe.h
> +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>  /*
> - * Copyright 2023 Rivos, Inc
> + * Copyright 2023-2024 Rivos, Inc
>   */
>
>  #ifndef _UAPI_ASM_HWPROBE_H
> @@ -67,6 +67,7 @@ struct riscv_hwprobe {
>  #define                RISCV_HWPROBE_MISALIGNED_UNSUPPORTED    (4 << 0)
>  #define                RISCV_HWPROBE_MISALIGNED_MASK           (7 << 0)
>  #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE    6
> +#define RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0   7
>  /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
>
>  /* Flags */
> diff --git a/arch/riscv/include/uapi/asm/vendor/thead.h b/arch/riscv/include/uapi/asm/vendor/thead.h
> new file mode 100644
> index 000000000000..43790ebe5faf
> --- /dev/null
> +++ b/arch/riscv/include/uapi/asm/vendor/thead.h
> @@ -0,0 +1,3 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +
> +#define                RISCV_HWPROBE_VENDOR_EXT_XTHEADVECTOR   (1 << 0)
> diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> index 8cae41a502dd..aeb70afe230b 100644
> --- a/arch/riscv/kernel/sys_hwprobe.c
> +++ b/arch/riscv/kernel/sys_hwprobe.c
> @@ -13,6 +13,7 @@
>  #include <asm/uaccess.h>
>  #include <asm/unistd.h>
>  #include <asm/vector.h>
> +#include <asm/vendor_extensions/thead_hwprobe.h>
>  #include <vdso/vsyscall.h>
>
>
> @@ -216,6 +217,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
>                         pair->value = riscv_cboz_block_size;
>                 break;
>
> +       case RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0:
> +               hwprobe_isa_vendor_ext_thead_0(pair, cpus);
> +               break;
> +
>         /*
>          * For forward compatibility, unknown keys don't fail the whole
>          * call, but get their element key set to -1 and value set to 0
> diff --git a/arch/riscv/kernel/vendor_extensions/Makefile b/arch/riscv/kernel/vendor_extensions/Makefile
> index 8f1c5a4dc38f..f511fd269e8a 100644
> --- a/arch/riscv/kernel/vendor_extensions/Makefile
> +++ b/arch/riscv/kernel/vendor_extensions/Makefile
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>
>  obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD)       += thead.o
> +obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD)       += thead_hwprobe.o
>  obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_ANDES)       += andes.o
> diff --git a/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c b/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c
> new file mode 100644
> index 000000000000..53f65942f7e8
> --- /dev/null
> +++ b/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c
> @@ -0,0 +1,19 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <asm/vendor_extensions/thead.h>
> +#include <asm/vendor_extensions/thead_hwprobe.h>
> +#include <asm/vendor_extensions/vendor_hwprobe.h>
> +
> +#include <linux/cpumask.h>
> +#include <linux/types.h>
> +
> +#include <uapi/asm/hwprobe.h>
> +#include <uapi/asm/vendor/thead.h>
> +
> +void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus)
> +{
> +       VENDOR_EXTENSION_SUPPORTED(pair, cpus,
> +                                  riscv_isa_vendor_ext_list_thead.per_hart_isa_bitmap, {
> +               EXT_KEY(XTHEADVECTOR);
> +       });
> +}

Very tidy!


>
> --
> 2.44.0
>

Re: [PATCH v5 15/17] riscv: hwprobe: Document thead vendor extensions and xtheadvector extension

[Evan Green]

On Thu, May 2, 2024 at 9:47 PM Charlie Jenkins <charlie@rivosinc.com> wrote:
>
> Document support for thead vendor extensions using the key
> RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 and xtheadvector extension using
> the key RISCV_HWPROBE_VENDOR_EXT_XTHEADVECTOR.
>
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>

Reviewed-by: Evan Green <evan@rivosinc.com>

Re: [PATCH v5 03/17] riscv: vector: Use vlenb from DT

[Conor Dooley]

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On Thu, May 02, 2024 at 09:46:38PM -0700, Charlie Jenkins wrote:
> If vlenb is provided in the device tree, prefer that over reading the
> vlenb csr.
> 
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> ---
>  arch/riscv/include/asm/cpufeature.h |  2 ++
>  arch/riscv/kernel/cpufeature.c      | 43 +++++++++++++++++++++++++++++++++++++
>  arch/riscv/kernel/vector.c          | 12 ++++++++++-
>  3 files changed, 56 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> index 347805446151..0c4f08577015 100644
> --- a/arch/riscv/include/asm/cpufeature.h
> +++ b/arch/riscv/include/asm/cpufeature.h
> @@ -31,6 +31,8 @@ DECLARE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);
>  /* Per-cpu ISA extensions. */
>  extern struct riscv_isainfo hart_isa[NR_CPUS];
>  
> +extern u32 riscv_vlenb_of;
> +
>  void riscv_user_isa_enable(void);
>  
>  #if defined(CONFIG_RISCV_MISALIGNED)
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 3ed2359eae35..12c79db0b0bb 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -35,6 +35,8 @@ static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
>  /* Per-cpu ISA extensions. */
>  struct riscv_isainfo hart_isa[NR_CPUS];
>  
> +u32 riscv_vlenb_of;
> +
>  /**
>   * riscv_isa_extension_base() - Get base extension word
>   *
> @@ -648,6 +650,42 @@ static int __init riscv_isa_fallback_setup(char *__unused)
>  early_param("riscv_isa_fallback", riscv_isa_fallback_setup);
>  #endif
>  
> +static int has_riscv_homogeneous_vlenb(void)
> +{
> +	int cpu;
> +	u32 prev_vlenb = 0;
> +	u32 vlenb;
> +
> +	for_each_possible_cpu(cpu) {
> +		struct device_node *cpu_node;
> +
> +		cpu_node = of_cpu_device_node_get(cpu);
> +		if (!cpu_node) {
> +			pr_warn("Unable to find cpu node\n");
> +			return -ENOENT;
> +		}
> +
> +		if (of_property_read_u32(cpu_node, "riscv,vlenb", &vlenb)) {
> +			of_node_put(cpu_node);
> +
> +			if (prev_vlenb)
> +				return -ENOENT;
> +			continue;
> +		}
> +
> +		if (prev_vlenb && vlenb != prev_vlenb) {
> +			of_node_put(cpu_node);
> +			return -ENOENT;
> +		}
> +
> +		prev_vlenb = vlenb;
> +		of_node_put(cpu_node);
> +	}
> +
> +	riscv_vlenb_of = vlenb;
> +	return 0;
> +}
> +
>  void __init riscv_fill_hwcap(void)
>  {
>  	char print_str[NUM_ALPHA_EXTS + 1];
> @@ -671,6 +709,11 @@ void __init riscv_fill_hwcap(void)
>  			pr_info("Falling back to deprecated \"riscv,isa\"\n");
>  			riscv_fill_hwcap_from_isa_string(isa2hwcap);
>  		}
> +
> +		if (elf_hwcap & COMPAT_HWCAP_ISA_V && has_riscv_homogeneous_vlenb() < 0) {

I still think this isn't quite right, as it will emit a warning when
RISCV_ISA_V is disabled. The simplest thing to do probably is just
add an `if (IS_ENABLED(CONFIG_RISCV_ISA_V) return 0` shortcut the to
function? It'll get disabled a few lines later so I think a zero is
safe.

> +			pr_warn("Unsupported heterogeneous vlen detected, vector extension disabled.\n");
> +			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
> +		}
>  	}
>  
>  	/*
> diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
> index 6727d1d3b8f2..e04586cdb7f0 100644
> --- a/arch/riscv/kernel/vector.c
> +++ b/arch/riscv/kernel/vector.c
> @@ -33,7 +33,17 @@ int riscv_v_setup_vsize(void)
>  {
>  	unsigned long this_vsize;
>  
> -	/* There are 32 vector registers with vlenb length. */
> +	/*
> +	 * There are 32 vector registers with vlenb length.
> +	 *
> +	 * If the riscv,vlenb property was provided by the firmware, use that
> +	 * instead of probing the CSRs.
> +	 */
> +	if (riscv_vlenb_of) {
> +		this_vsize = riscv_vlenb_of * 32;
> +		return 0;
> +	}
> +
>  	riscv_v_enable();
>  	this_vsize = csr_read(CSR_VLENB) * 32;
>  	riscv_v_disable();
> 
> -- 
> 2.44.0
> 

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Re: [PATCH v5 05/17] riscv: Extend cpufeature.c to detect vendor extensions

[Charlie Jenkins]

On Fri, May 03, 2024 at 09:28:24AM -0700, Evan Green wrote:
> On Thu, May 2, 2024 at 9:46 PM Charlie Jenkins <charlie@rivosinc.com> wrote:
> >
> > Separate vendor extensions out into one struct per vendor
> > instead of adding vendor extensions onto riscv_isa_ext.
> >
> > Add a hidden config RISCV_ISA_VENDOR_EXT to conditionally include this
> > code.
> >
> > The xtheadvector vendor extension is added using these changes.
> >
> > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> > ---
> >  arch/riscv/Kconfig                               |  2 +
> >  arch/riscv/Kconfig.vendor                        | 19 +++++
> >  arch/riscv/include/asm/cpufeature.h              | 18 +++++
> >  arch/riscv/include/asm/vendor_extensions.h       | 34 +++++++++
> >  arch/riscv/include/asm/vendor_extensions/thead.h | 16 ++++
> >  arch/riscv/kernel/Makefile                       |  2 +
> >  arch/riscv/kernel/cpufeature.c                   | 93 +++++++++++++++++++-----
> >  arch/riscv/kernel/vendor_extensions.c            | 18 +++++
> >  arch/riscv/kernel/vendor_extensions/Makefile     |  3 +
> >  arch/riscv/kernel/vendor_extensions/thead.c      | 18 +++++
> >  10 files changed, 203 insertions(+), 20 deletions(-)
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index be09c8836d56..fec86fba3acd 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -759,6 +759,8 @@ config RISCV_EFFICIENT_UNALIGNED_ACCESS
> >
> >  endchoice
> >
> > +source "arch/riscv/Kconfig.vendor"
> > +
> >  endmenu # "Platform type"
> >
> >  menu "Kernel features"
> > diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor
> > new file mode 100644
> > index 000000000000..85ac30496b0e
> > --- /dev/null
> > +++ b/arch/riscv/Kconfig.vendor
> > @@ -0,0 +1,19 @@
> > +menu "Vendor extensions"
> > +
> > +config RISCV_ISA_VENDOR_EXT
> > +       bool
> > +
> > +menu "T-Head"
> > +config RISCV_ISA_VENDOR_EXT_THEAD
> > +       bool "T-Head vendor extension support"
> > +       select RISCV_ISA_VENDOR_EXT
> > +       default y
> > +       help
> > +         Say N here to disable detection of and support for all T-Head vendor
> > +         extensions. Without this option enabled, T-Head vendor extensions will
> > +         not be detected at boot and their presence not reported to userspace.
> > +
> > +         If you don't know what to do here, say Y.
> > +endmenu
> > +
> > +endmenu
> > diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> > index 0c4f08577015..fedd479ccfd1 100644
> > --- a/arch/riscv/include/asm/cpufeature.h
> > +++ b/arch/riscv/include/asm/cpufeature.h
> > @@ -35,6 +35,24 @@ extern u32 riscv_vlenb_of;
> >
> >  void riscv_user_isa_enable(void);
> >
> > +#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> > +       .name = #_name,                                                         \
> > +       .property = #_name,                                                     \
> > +       .id = _id,                                                              \
> > +       .subset_ext_ids = _subset_exts,                                         \
> > +       .subset_ext_size = _subset_exts_size                                    \
> > +}
> > +
> > +#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> > +
> > +/* Used to declare pure "lasso" extension (Zk for instance) */
> > +#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> > +       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> > +
> > +/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> > +#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> > +       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> > +
> >  #if defined(CONFIG_RISCV_MISALIGNED)
> >  bool check_unaligned_access_emulated_all_cpus(void);
> >  void unaligned_emulation_finish(void);
> > diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
> > new file mode 100644
> > index 000000000000..bf4dac66e6e6
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/vendor_extensions.h
> > @@ -0,0 +1,34 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright 2024 Rivos, Inc
> > + */
> > +
> > +#ifndef _ASM_VENDOR_EXTENSIONS_H
> > +#define _ASM_VENDOR_EXTENSIONS_H
> > +
> > +#include <asm/cpufeature.h>
> > +
> > +#include <linux/array_size.h>
> > +#include <linux/types.h>
> > +
> > +/*
> > + * The extension keys of each vendor must be strictly less than this value.
> > + */
> > +#define RISCV_ISA_VENDOR_EXT_MAX 32
> > +
> > +struct riscv_isavendorinfo {
> > +       DECLARE_BITMAP(isa, RISCV_ISA_VENDOR_EXT_MAX);
> > +};
> 
> Nice, I think this was a good compromise: being honest with the
> compiler about the fixed array sizes, with the tradeoff that all
> vendors have to use the same ceiling for the number of bits. If one
> vendor raises this ceiling absurdly and starts creating huge amounts
> of waste we can revisit.
> 
> > +
> > +struct riscv_isa_vendor_ext_data_list {
> > +       const size_t ext_data_count;
> > +       const struct riscv_isa_ext_data *ext_data;
> > +       struct riscv_isavendorinfo per_hart_isa_bitmap[NR_CPUS];
> > +       struct riscv_isavendorinfo all_harts_isa_bitmap;
> > +};
> > +
> > +extern struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[];
> > +
> > +extern const size_t riscv_isa_vendor_ext_list_size;
> > +
> > +#endif /* _ASM_VENDOR_EXTENSIONS_H */
> > diff --git a/arch/riscv/include/asm/vendor_extensions/thead.h b/arch/riscv/include/asm/vendor_extensions/thead.h
> > new file mode 100644
> > index 000000000000..48421d1553ad
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/vendor_extensions/thead.h
> > @@ -0,0 +1,16 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> > +#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> > +
> > +#include <asm/vendor_extensions.h>
> > +
> > +#include <linux/types.h>
> > +
> > +/*
> > + * Extension keys must be strictly less than RISCV_ISA_VENDOR_EXT_MAX.
> > + */
> > +#define RISCV_ISA_VENDOR_EXT_XTHEADVECTOR              0
> > +
> > +extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead;
> > +
> > +#endif
> > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> > index 81d94a8ee10f..53361c50fb46 100644
> > --- a/arch/riscv/kernel/Makefile
> > +++ b/arch/riscv/kernel/Makefile
> > @@ -58,6 +58,8 @@ obj-y += riscv_ksyms.o
> >  obj-y  += stacktrace.o
> >  obj-y  += cacheinfo.o
> >  obj-y  += patch.o
> > +obj-y  += vendor_extensions.o
> > +obj-y  += vendor_extensions/
> >  obj-y  += probes/
> >  obj-y  += tests/
> >  obj-$(CONFIG_MMU) += vdso.o vdso/
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index 12c79db0b0bb..cc9ec393c8f6 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -24,6 +24,7 @@
> >  #include <asm/processor.h>
> >  #include <asm/sbi.h>
> >  #include <asm/vector.h>
> > +#include <asm/vendor_extensions.h>
> >
> >  #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
> >
> > @@ -102,24 +103,6 @@ static bool riscv_isa_extension_check(int id)
> >         return true;
> >  }
> >
> > -#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> > -       .name = #_name,                                                         \
> > -       .property = #_name,                                                     \
> > -       .id = _id,                                                              \
> > -       .subset_ext_ids = _subset_exts,                                         \
> > -       .subset_ext_size = _subset_exts_size                                    \
> > -}
> > -
> > -#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> > -
> > -/* Used to declare pure "lasso" extension (Zk for instance) */
> > -#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> > -       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> > -
> > -/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> > -#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> > -       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> > -
> >  static const unsigned int riscv_zk_bundled_exts[] = {
> >         RISCV_ISA_EXT_ZBKB,
> >         RISCV_ISA_EXT_ZBKC,
> > @@ -353,6 +336,21 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
> >                 bool ext_long = false, ext_err = false;
> >
> >                 switch (*ext) {
> > +               case 'x':
> > +               case 'X':
> > +                       if (acpi_disabled)
> > +                               pr_warn_once("Vendor extensions are ignored in riscv,isa. Use riscv,isa-extensions instead.");
> > +                       /*
> > +                        * To skip an extension, we find its end.
> > +                        * As multi-letter extensions must be split from other multi-letter
> > +                        * extensions with an "_", the end of a multi-letter extension will
> > +                        * either be the null character or the "_" at the start of the next
> > +                        * multi-letter extension.
> > +                        */
> > +                       for (; *isa && *isa != '_'; ++isa)
> > +                               ;
> > +                       ext_err = true;
> > +                       break;
> >                 case 's':
> >                         /*
> >                          * Workaround for invalid single-letter 's' & 'u' (QEMU).
> > @@ -368,8 +366,6 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
> >                         }
> >                         fallthrough;
> >                 case 'S':
> > -               case 'x':
> > -               case 'X':
> >                 case 'z':
> >                 case 'Z':
> >                         /*
> > @@ -572,6 +568,59 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
> >                 acpi_put_table((struct acpi_table_header *)rhct);
> >  }
> >
> > +static void __init riscv_fill_cpu_vendor_ext(struct device_node *cpu_node, int cpu)
> > +{
> > +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> > +               return;
> > +
> > +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> > +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> > +
> > +               for (int j = 0; j < ext_list->ext_data_count; j++) {
> > +                       const struct riscv_isa_ext_data ext = ext_list->ext_data[j];
> > +                       struct riscv_isavendorinfo *isavendorinfo = &ext_list->per_hart_isa_bitmap[cpu];
> > +
> > +                       if (of_property_match_string(cpu_node, "riscv,isa-extensions",
> > +                                                    ext.property) < 0)
> > +                               continue;
> > +
> > +                       /*
> > +                        * Assume that subset extensions are all members of the
> > +                        * same vendor.
> > +                        */
> > +                       if (ext.subset_ext_size)
> > +                               for (int k = 0; k < ext.subset_ext_size; k++)
> > +                                       set_bit(ext.subset_ext_ids[k], isavendorinfo->isa);
> > +
> > +                       set_bit(ext.id, isavendorinfo->isa);
> > +               }
> > +       }
> > +}
> > +
> > +static void __init riscv_fill_vendor_ext_list(int cpu)
> > +{
> > +       bool first = true;
> > +
> > +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> > +               return;
> > +
> > +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> > +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> > +
> > +               if (first) {
> > +                       bitmap_copy(ext_list->all_harts_isa_bitmap.isa,
> > +                                   ext_list->per_hart_isa_bitmap[cpu].isa,
> > +                                   RISCV_ISA_VENDOR_EXT_MAX);
> > +                       first = false;
> 
> I think this is still not quite right. This behaves properly when
> called on the first cpu (let's say 0), but then we call it again with
> cpu 1, first gets set to true, and we clobber the old work we did for
> cpu 0. If we knew that cpu 0 was always called first (this looks true
> since both calls are within a for_each_possible_cpu() loop), and that
> this was only called once at boot for cpu 0 (looks true, and
> riscv_fill_hwcap() is __init), then it could be bool first = cpu == 0.

Assuming that the first cpu is 0 should be safe, but to eliminate that
assumption we can pass in a "first" parameter into this function that
will only be true the first time this function is called. We also keep
"first = false" in this function so the copy only happens on the first
iteration of the first cpu.

- Charlie

Re: [PATCH v5 05/17] riscv: Extend cpufeature.c to detect vendor extensions

[Evan Green]

On Fri, May 3, 2024 at 10:08 AM Charlie Jenkins <charlie@rivosinc.com> wrote:
>
> On Fri, May 03, 2024 at 09:28:24AM -0700, Evan Green wrote:
> > On Thu, May 2, 2024 at 9:46 PM Charlie Jenkins <charlie@rivosinc.com> wrote:
> > >
> > > Separate vendor extensions out into one struct per vendor
> > > instead of adding vendor extensions onto riscv_isa_ext.
> > >
> > > Add a hidden config RISCV_ISA_VENDOR_EXT to conditionally include this
> > > code.
> > >
> > > The xtheadvector vendor extension is added using these changes.
> > >
> > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> > > ---
> > >  arch/riscv/Kconfig                               |  2 +
> > >  arch/riscv/Kconfig.vendor                        | 19 +++++
> > >  arch/riscv/include/asm/cpufeature.h              | 18 +++++
> > >  arch/riscv/include/asm/vendor_extensions.h       | 34 +++++++++
> > >  arch/riscv/include/asm/vendor_extensions/thead.h | 16 ++++
> > >  arch/riscv/kernel/Makefile                       |  2 +
> > >  arch/riscv/kernel/cpufeature.c                   | 93 +++++++++++++++++++-----
> > >  arch/riscv/kernel/vendor_extensions.c            | 18 +++++
> > >  arch/riscv/kernel/vendor_extensions/Makefile     |  3 +
> > >  arch/riscv/kernel/vendor_extensions/thead.c      | 18 +++++
> > >  10 files changed, 203 insertions(+), 20 deletions(-)
> > >
> > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > > index be09c8836d56..fec86fba3acd 100644
> > > --- a/arch/riscv/Kconfig
> > > +++ b/arch/riscv/Kconfig
> > > @@ -759,6 +759,8 @@ config RISCV_EFFICIENT_UNALIGNED_ACCESS
> > >
> > >  endchoice
> > >
> > > +source "arch/riscv/Kconfig.vendor"
> > > +
> > >  endmenu # "Platform type"
> > >
> > >  menu "Kernel features"
> > > diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor
> > > new file mode 100644
> > > index 000000000000..85ac30496b0e
> > > --- /dev/null
> > > +++ b/arch/riscv/Kconfig.vendor
> > > @@ -0,0 +1,19 @@
> > > +menu "Vendor extensions"
> > > +
> > > +config RISCV_ISA_VENDOR_EXT
> > > +       bool
> > > +
> > > +menu "T-Head"
> > > +config RISCV_ISA_VENDOR_EXT_THEAD
> > > +       bool "T-Head vendor extension support"
> > > +       select RISCV_ISA_VENDOR_EXT
> > > +       default y
> > > +       help
> > > +         Say N here to disable detection of and support for all T-Head vendor
> > > +         extensions. Without this option enabled, T-Head vendor extensions will
> > > +         not be detected at boot and their presence not reported to userspace.
> > > +
> > > +         If you don't know what to do here, say Y.
> > > +endmenu
> > > +
> > > +endmenu
> > > diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> > > index 0c4f08577015..fedd479ccfd1 100644
> > > --- a/arch/riscv/include/asm/cpufeature.h
> > > +++ b/arch/riscv/include/asm/cpufeature.h
> > > @@ -35,6 +35,24 @@ extern u32 riscv_vlenb_of;
> > >
> > >  void riscv_user_isa_enable(void);
> > >
> > > +#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> > > +       .name = #_name,                                                         \
> > > +       .property = #_name,                                                     \
> > > +       .id = _id,                                                              \
> > > +       .subset_ext_ids = _subset_exts,                                         \
> > > +       .subset_ext_size = _subset_exts_size                                    \
> > > +}
> > > +
> > > +#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> > > +
> > > +/* Used to declare pure "lasso" extension (Zk for instance) */
> > > +#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> > > +       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> > > +
> > > +/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> > > +#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> > > +       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> > > +
> > >  #if defined(CONFIG_RISCV_MISALIGNED)
> > >  bool check_unaligned_access_emulated_all_cpus(void);
> > >  void unaligned_emulation_finish(void);
> > > diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
> > > new file mode 100644
> > > index 000000000000..bf4dac66e6e6
> > > --- /dev/null
> > > +++ b/arch/riscv/include/asm/vendor_extensions.h
> > > @@ -0,0 +1,34 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > +/*
> > > + * Copyright 2024 Rivos, Inc
> > > + */
> > > +
> > > +#ifndef _ASM_VENDOR_EXTENSIONS_H
> > > +#define _ASM_VENDOR_EXTENSIONS_H
> > > +
> > > +#include <asm/cpufeature.h>
> > > +
> > > +#include <linux/array_size.h>
> > > +#include <linux/types.h>
> > > +
> > > +/*
> > > + * The extension keys of each vendor must be strictly less than this value.
> > > + */
> > > +#define RISCV_ISA_VENDOR_EXT_MAX 32
> > > +
> > > +struct riscv_isavendorinfo {
> > > +       DECLARE_BITMAP(isa, RISCV_ISA_VENDOR_EXT_MAX);
> > > +};
> >
> > Nice, I think this was a good compromise: being honest with the
> > compiler about the fixed array sizes, with the tradeoff that all
> > vendors have to use the same ceiling for the number of bits. If one
> > vendor raises this ceiling absurdly and starts creating huge amounts
> > of waste we can revisit.
> >
> > > +
> > > +struct riscv_isa_vendor_ext_data_list {
> > > +       const size_t ext_data_count;
> > > +       const struct riscv_isa_ext_data *ext_data;
> > > +       struct riscv_isavendorinfo per_hart_isa_bitmap[NR_CPUS];
> > > +       struct riscv_isavendorinfo all_harts_isa_bitmap;
> > > +};
> > > +
> > > +extern struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[];
> > > +
> > > +extern const size_t riscv_isa_vendor_ext_list_size;
> > > +
> > > +#endif /* _ASM_VENDOR_EXTENSIONS_H */
> > > diff --git a/arch/riscv/include/asm/vendor_extensions/thead.h b/arch/riscv/include/asm/vendor_extensions/thead.h
> > > new file mode 100644
> > > index 000000000000..48421d1553ad
> > > --- /dev/null
> > > +++ b/arch/riscv/include/asm/vendor_extensions/thead.h
> > > @@ -0,0 +1,16 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> > > +#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> > > +
> > > +#include <asm/vendor_extensions.h>
> > > +
> > > +#include <linux/types.h>
> > > +
> > > +/*
> > > + * Extension keys must be strictly less than RISCV_ISA_VENDOR_EXT_MAX.
> > > + */
> > > +#define RISCV_ISA_VENDOR_EXT_XTHEADVECTOR              0
> > > +
> > > +extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead;
> > > +
> > > +#endif
> > > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> > > index 81d94a8ee10f..53361c50fb46 100644
> > > --- a/arch/riscv/kernel/Makefile
> > > +++ b/arch/riscv/kernel/Makefile
> > > @@ -58,6 +58,8 @@ obj-y += riscv_ksyms.o
> > >  obj-y  += stacktrace.o
> > >  obj-y  += cacheinfo.o
> > >  obj-y  += patch.o
> > > +obj-y  += vendor_extensions.o
> > > +obj-y  += vendor_extensions/
> > >  obj-y  += probes/
> > >  obj-y  += tests/
> > >  obj-$(CONFIG_MMU) += vdso.o vdso/
> > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > > index 12c79db0b0bb..cc9ec393c8f6 100644
> > > --- a/arch/riscv/kernel/cpufeature.c
> > > +++ b/arch/riscv/kernel/cpufeature.c
> > > @@ -24,6 +24,7 @@
> > >  #include <asm/processor.h>
> > >  #include <asm/sbi.h>
> > >  #include <asm/vector.h>
> > > +#include <asm/vendor_extensions.h>
> > >
> > >  #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
> > >
> > > @@ -102,24 +103,6 @@ static bool riscv_isa_extension_check(int id)
> > >         return true;
> > >  }
> > >
> > > -#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> > > -       .name = #_name,                                                         \
> > > -       .property = #_name,                                                     \
> > > -       .id = _id,                                                              \
> > > -       .subset_ext_ids = _subset_exts,                                         \
> > > -       .subset_ext_size = _subset_exts_size                                    \
> > > -}
> > > -
> > > -#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> > > -
> > > -/* Used to declare pure "lasso" extension (Zk for instance) */
> > > -#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> > > -       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> > > -
> > > -/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> > > -#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> > > -       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> > > -
> > >  static const unsigned int riscv_zk_bundled_exts[] = {
> > >         RISCV_ISA_EXT_ZBKB,
> > >         RISCV_ISA_EXT_ZBKC,
> > > @@ -353,6 +336,21 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
> > >                 bool ext_long = false, ext_err = false;
> > >
> > >                 switch (*ext) {
> > > +               case 'x':
> > > +               case 'X':
> > > +                       if (acpi_disabled)
> > > +                               pr_warn_once("Vendor extensions are ignored in riscv,isa. Use riscv,isa-extensions instead.");
> > > +                       /*
> > > +                        * To skip an extension, we find its end.
> > > +                        * As multi-letter extensions must be split from other multi-letter
> > > +                        * extensions with an "_", the end of a multi-letter extension will
> > > +                        * either be the null character or the "_" at the start of the next
> > > +                        * multi-letter extension.
> > > +                        */
> > > +                       for (; *isa && *isa != '_'; ++isa)
> > > +                               ;
> > > +                       ext_err = true;
> > > +                       break;
> > >                 case 's':
> > >                         /*
> > >                          * Workaround for invalid single-letter 's' & 'u' (QEMU).
> > > @@ -368,8 +366,6 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
> > >                         }
> > >                         fallthrough;
> > >                 case 'S':
> > > -               case 'x':
> > > -               case 'X':
> > >                 case 'z':
> > >                 case 'Z':
> > >                         /*
> > > @@ -572,6 +568,59 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
> > >                 acpi_put_table((struct acpi_table_header *)rhct);
> > >  }
> > >
> > > +static void __init riscv_fill_cpu_vendor_ext(struct device_node *cpu_node, int cpu)
> > > +{
> > > +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> > > +               return;
> > > +
> > > +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> > > +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> > > +
> > > +               for (int j = 0; j < ext_list->ext_data_count; j++) {
> > > +                       const struct riscv_isa_ext_data ext = ext_list->ext_data[j];
> > > +                       struct riscv_isavendorinfo *isavendorinfo = &ext_list->per_hart_isa_bitmap[cpu];
> > > +
> > > +                       if (of_property_match_string(cpu_node, "riscv,isa-extensions",
> > > +                                                    ext.property) < 0)
> > > +                               continue;
> > > +
> > > +                       /*
> > > +                        * Assume that subset extensions are all members of the
> > > +                        * same vendor.
> > > +                        */
> > > +                       if (ext.subset_ext_size)
> > > +                               for (int k = 0; k < ext.subset_ext_size; k++)
> > > +                                       set_bit(ext.subset_ext_ids[k], isavendorinfo->isa);
> > > +
> > > +                       set_bit(ext.id, isavendorinfo->isa);
> > > +               }
> > > +       }
> > > +}
> > > +
> > > +static void __init riscv_fill_vendor_ext_list(int cpu)
> > > +{
> > > +       bool first = true;
> > > +
> > > +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> > > +               return;
> > > +
> > > +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> > > +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> > > +
> > > +               if (first) {
> > > +                       bitmap_copy(ext_list->all_harts_isa_bitmap.isa,
> > > +                                   ext_list->per_hart_isa_bitmap[cpu].isa,
> > > +                                   RISCV_ISA_VENDOR_EXT_MAX);
> > > +                       first = false;
> >
> > I think this is still not quite right. This behaves properly when
> > called on the first cpu (let's say 0), but then we call it again with
> > cpu 1, first gets set to true, and we clobber the old work we did for
> > cpu 0. If we knew that cpu 0 was always called first (this looks true
> > since both calls are within a for_each_possible_cpu() loop), and that
> > this was only called once at boot for cpu 0 (looks true, and
> > riscv_fill_hwcap() is __init), then it could be bool first = cpu == 0.
>
> Assuming that the first cpu is 0 should be safe, but to eliminate that
> assumption we can pass in a "first" parameter into this function that
> will only be true the first time this function is called. We also keep
> "first = false" in this function so the copy only happens on the first
> iteration of the first cpu.

Yeah, though then you still have to maintain that the function passing
true as the first parameter really is the first invocation.

static bool first = true would also fix it, maybe more reliably. Are
static locals allowed in the kernel?

>
> - Charlie
>

Re: [PATCH v5 03/17] riscv: vector: Use vlenb from DT

[Charlie Jenkins]

On Fri, May 03, 2024 at 05:59:33PM +0100, Conor Dooley wrote:
> On Thu, May 02, 2024 at 09:46:38PM -0700, Charlie Jenkins wrote:
> > If vlenb is provided in the device tree, prefer that over reading the
> > vlenb csr.
> > 
> > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> > ---
> >  arch/riscv/include/asm/cpufeature.h |  2 ++
> >  arch/riscv/kernel/cpufeature.c      | 43 +++++++++++++++++++++++++++++++++++++
> >  arch/riscv/kernel/vector.c          | 12 ++++++++++-
> >  3 files changed, 56 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> > index 347805446151..0c4f08577015 100644
> > --- a/arch/riscv/include/asm/cpufeature.h
> > +++ b/arch/riscv/include/asm/cpufeature.h
> > @@ -31,6 +31,8 @@ DECLARE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);
> >  /* Per-cpu ISA extensions. */
> >  extern struct riscv_isainfo hart_isa[NR_CPUS];
> >  
> > +extern u32 riscv_vlenb_of;
> > +
> >  void riscv_user_isa_enable(void);
> >  
> >  #if defined(CONFIG_RISCV_MISALIGNED)
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index 3ed2359eae35..12c79db0b0bb 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -35,6 +35,8 @@ static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> >  /* Per-cpu ISA extensions. */
> >  struct riscv_isainfo hart_isa[NR_CPUS];
> >  
> > +u32 riscv_vlenb_of;
> > +
> >  /**
> >   * riscv_isa_extension_base() - Get base extension word
> >   *
> > @@ -648,6 +650,42 @@ static int __init riscv_isa_fallback_setup(char *__unused)
> >  early_param("riscv_isa_fallback", riscv_isa_fallback_setup);
> >  #endif
> >  
> > +static int has_riscv_homogeneous_vlenb(void)
> > +{
> > +	int cpu;
> > +	u32 prev_vlenb = 0;
> > +	u32 vlenb;
> > +
> > +	for_each_possible_cpu(cpu) {
> > +		struct device_node *cpu_node;
> > +
> > +		cpu_node = of_cpu_device_node_get(cpu);
> > +		if (!cpu_node) {
> > +			pr_warn("Unable to find cpu node\n");
> > +			return -ENOENT;
> > +		}
> > +
> > +		if (of_property_read_u32(cpu_node, "riscv,vlenb", &vlenb)) {
> > +			of_node_put(cpu_node);
> > +
> > +			if (prev_vlenb)
> > +				return -ENOENT;
> > +			continue;
> > +		}
> > +
> > +		if (prev_vlenb && vlenb != prev_vlenb) {
> > +			of_node_put(cpu_node);
> > +			return -ENOENT;
> > +		}
> > +
> > +		prev_vlenb = vlenb;
> > +		of_node_put(cpu_node);
> > +	}
> > +
> > +	riscv_vlenb_of = vlenb;
> > +	return 0;
> > +}
> > +
> >  void __init riscv_fill_hwcap(void)
> >  {
> >  	char print_str[NUM_ALPHA_EXTS + 1];
> > @@ -671,6 +709,11 @@ void __init riscv_fill_hwcap(void)
> >  			pr_info("Falling back to deprecated \"riscv,isa\"\n");
> >  			riscv_fill_hwcap_from_isa_string(isa2hwcap);
> >  		}
> > +
> > +		if (elf_hwcap & COMPAT_HWCAP_ISA_V && has_riscv_homogeneous_vlenb() < 0) {
> 
> I still think this isn't quite right, as it will emit a warning when
> RISCV_ISA_V is disabled. The simplest thing to do probably is just
> add an `if (IS_ENABLED(CONFIG_RISCV_ISA_V) return 0` shortcut the to
> function? It'll get disabled a few lines later so I think a zero is
> safe.

That seems like a good idea. It is weird to throw a warning about this
even when they have V disabled in the kernel. The DT is improperly
formatted since it has heterogeneous vlenb entries and has V enabled,
but since the user disabled V in the kernel skipping the warning is
reasonable.

- Charlie

> 
> > +			pr_warn("Unsupported heterogeneous vlen detected, vector extension disabled.\n");
> > +			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
> > +		}
> >  	}
> >  
> >  	/*
> > diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
> > index 6727d1d3b8f2..e04586cdb7f0 100644
> > --- a/arch/riscv/kernel/vector.c
> > +++ b/arch/riscv/kernel/vector.c
> > @@ -33,7 +33,17 @@ int riscv_v_setup_vsize(void)
> >  {
> >  	unsigned long this_vsize;
> >  
> > -	/* There are 32 vector registers with vlenb length. */
> > +	/*
> > +	 * There are 32 vector registers with vlenb length.
> > +	 *
> > +	 * If the riscv,vlenb property was provided by the firmware, use that
> > +	 * instead of probing the CSRs.
> > +	 */
> > +	if (riscv_vlenb_of) {
> > +		this_vsize = riscv_vlenb_of * 32;
> > +		return 0;
> > +	}
> > +
> >  	riscv_v_enable();
> >  	this_vsize = csr_read(CSR_VLENB) * 32;
> >  	riscv_v_disable();
> > 
> > -- 
> > 2.44.0
> > 

Re: [PATCH v5 03/17] riscv: vector: Use vlenb from DT

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 421 bytes --]

On Fri, May 03, 2024 at 10:15:16AM -0700, Charlie Jenkins wrote:
> The DT is improperly
> formatted since it has heterogeneous vlenb entries and has V enabled,
> but since the user disabled V in the kernel skipping the warning is
> reasonable.

I wouldn't go as far as "improperly formatted", as if the harts really
do have differing vector lengths, it's correctly formatted. It's just
not something we support in Linux.

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Re: [PATCH v5 05/17] riscv: Extend cpufeature.c to detect vendor extensions

[Charlie Jenkins]

On Fri, May 03, 2024 at 10:13:33AM -0700, Evan Green wrote:
> On Fri, May 3, 2024 at 10:08 AM Charlie Jenkins <charlie@rivosinc.com> wrote:
> >
> > On Fri, May 03, 2024 at 09:28:24AM -0700, Evan Green wrote:
> > > On Thu, May 2, 2024 at 9:46 PM Charlie Jenkins <charlie@rivosinc.com> wrote:
> > > >
> > > > Separate vendor extensions out into one struct per vendor
> > > > instead of adding vendor extensions onto riscv_isa_ext.
> > > >
> > > > Add a hidden config RISCV_ISA_VENDOR_EXT to conditionally include this
> > > > code.
> > > >
> > > > The xtheadvector vendor extension is added using these changes.
> > > >
> > > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> > > > ---
> > > >  arch/riscv/Kconfig                               |  2 +
> > > >  arch/riscv/Kconfig.vendor                        | 19 +++++
> > > >  arch/riscv/include/asm/cpufeature.h              | 18 +++++
> > > >  arch/riscv/include/asm/vendor_extensions.h       | 34 +++++++++
> > > >  arch/riscv/include/asm/vendor_extensions/thead.h | 16 ++++
> > > >  arch/riscv/kernel/Makefile                       |  2 +
> > > >  arch/riscv/kernel/cpufeature.c                   | 93 +++++++++++++++++++-----
> > > >  arch/riscv/kernel/vendor_extensions.c            | 18 +++++
> > > >  arch/riscv/kernel/vendor_extensions/Makefile     |  3 +
> > > >  arch/riscv/kernel/vendor_extensions/thead.c      | 18 +++++
> > > >  10 files changed, 203 insertions(+), 20 deletions(-)
> > > >
> > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > > > index be09c8836d56..fec86fba3acd 100644
> > > > --- a/arch/riscv/Kconfig
> > > > +++ b/arch/riscv/Kconfig
> > > > @@ -759,6 +759,8 @@ config RISCV_EFFICIENT_UNALIGNED_ACCESS
> > > >
> > > >  endchoice
> > > >
> > > > +source "arch/riscv/Kconfig.vendor"
> > > > +
> > > >  endmenu # "Platform type"
> > > >
> > > >  menu "Kernel features"
> > > > diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor
> > > > new file mode 100644
> > > > index 000000000000..85ac30496b0e
> > > > --- /dev/null
> > > > +++ b/arch/riscv/Kconfig.vendor
> > > > @@ -0,0 +1,19 @@
> > > > +menu "Vendor extensions"
> > > > +
> > > > +config RISCV_ISA_VENDOR_EXT
> > > > +       bool
> > > > +
> > > > +menu "T-Head"
> > > > +config RISCV_ISA_VENDOR_EXT_THEAD
> > > > +       bool "T-Head vendor extension support"
> > > > +       select RISCV_ISA_VENDOR_EXT
> > > > +       default y
> > > > +       help
> > > > +         Say N here to disable detection of and support for all T-Head vendor
> > > > +         extensions. Without this option enabled, T-Head vendor extensions will
> > > > +         not be detected at boot and their presence not reported to userspace.
> > > > +
> > > > +         If you don't know what to do here, say Y.
> > > > +endmenu
> > > > +
> > > > +endmenu
> > > > diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
> > > > index 0c4f08577015..fedd479ccfd1 100644
> > > > --- a/arch/riscv/include/asm/cpufeature.h
> > > > +++ b/arch/riscv/include/asm/cpufeature.h
> > > > @@ -35,6 +35,24 @@ extern u32 riscv_vlenb_of;
> > > >
> > > >  void riscv_user_isa_enable(void);
> > > >
> > > > +#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> > > > +       .name = #_name,                                                         \
> > > > +       .property = #_name,                                                     \
> > > > +       .id = _id,                                                              \
> > > > +       .subset_ext_ids = _subset_exts,                                         \
> > > > +       .subset_ext_size = _subset_exts_size                                    \
> > > > +}
> > > > +
> > > > +#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> > > > +
> > > > +/* Used to declare pure "lasso" extension (Zk for instance) */
> > > > +#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> > > > +       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> > > > +
> > > > +/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> > > > +#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> > > > +       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> > > > +
> > > >  #if defined(CONFIG_RISCV_MISALIGNED)
> > > >  bool check_unaligned_access_emulated_all_cpus(void);
> > > >  void unaligned_emulation_finish(void);
> > > > diff --git a/arch/riscv/include/asm/vendor_extensions.h b/arch/riscv/include/asm/vendor_extensions.h
> > > > new file mode 100644
> > > > index 000000000000..bf4dac66e6e6
> > > > --- /dev/null
> > > > +++ b/arch/riscv/include/asm/vendor_extensions.h
> > > > @@ -0,0 +1,34 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > > +/*
> > > > + * Copyright 2024 Rivos, Inc
> > > > + */
> > > > +
> > > > +#ifndef _ASM_VENDOR_EXTENSIONS_H
> > > > +#define _ASM_VENDOR_EXTENSIONS_H
> > > > +
> > > > +#include <asm/cpufeature.h>
> > > > +
> > > > +#include <linux/array_size.h>
> > > > +#include <linux/types.h>
> > > > +
> > > > +/*
> > > > + * The extension keys of each vendor must be strictly less than this value.
> > > > + */
> > > > +#define RISCV_ISA_VENDOR_EXT_MAX 32
> > > > +
> > > > +struct riscv_isavendorinfo {
> > > > +       DECLARE_BITMAP(isa, RISCV_ISA_VENDOR_EXT_MAX);
> > > > +};
> > >
> > > Nice, I think this was a good compromise: being honest with the
> > > compiler about the fixed array sizes, with the tradeoff that all
> > > vendors have to use the same ceiling for the number of bits. If one
> > > vendor raises this ceiling absurdly and starts creating huge amounts
> > > of waste we can revisit.
> > >
> > > > +
> > > > +struct riscv_isa_vendor_ext_data_list {
> > > > +       const size_t ext_data_count;
> > > > +       const struct riscv_isa_ext_data *ext_data;
> > > > +       struct riscv_isavendorinfo per_hart_isa_bitmap[NR_CPUS];
> > > > +       struct riscv_isavendorinfo all_harts_isa_bitmap;
> > > > +};
> > > > +
> > > > +extern struct riscv_isa_vendor_ext_data_list *riscv_isa_vendor_ext_list[];
> > > > +
> > > > +extern const size_t riscv_isa_vendor_ext_list_size;
> > > > +
> > > > +#endif /* _ASM_VENDOR_EXTENSIONS_H */
> > > > diff --git a/arch/riscv/include/asm/vendor_extensions/thead.h b/arch/riscv/include/asm/vendor_extensions/thead.h
> > > > new file mode 100644
> > > > index 000000000000..48421d1553ad
> > > > --- /dev/null
> > > > +++ b/arch/riscv/include/asm/vendor_extensions/thead.h
> > > > @@ -0,0 +1,16 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > > +#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> > > > +#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_H
> > > > +
> > > > +#include <asm/vendor_extensions.h>
> > > > +
> > > > +#include <linux/types.h>
> > > > +
> > > > +/*
> > > > + * Extension keys must be strictly less than RISCV_ISA_VENDOR_EXT_MAX.
> > > > + */
> > > > +#define RISCV_ISA_VENDOR_EXT_XTHEADVECTOR              0
> > > > +
> > > > +extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead;
> > > > +
> > > > +#endif
> > > > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> > > > index 81d94a8ee10f..53361c50fb46 100644
> > > > --- a/arch/riscv/kernel/Makefile
> > > > +++ b/arch/riscv/kernel/Makefile
> > > > @@ -58,6 +58,8 @@ obj-y += riscv_ksyms.o
> > > >  obj-y  += stacktrace.o
> > > >  obj-y  += cacheinfo.o
> > > >  obj-y  += patch.o
> > > > +obj-y  += vendor_extensions.o
> > > > +obj-y  += vendor_extensions/
> > > >  obj-y  += probes/
> > > >  obj-y  += tests/
> > > >  obj-$(CONFIG_MMU) += vdso.o vdso/
> > > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > > > index 12c79db0b0bb..cc9ec393c8f6 100644
> > > > --- a/arch/riscv/kernel/cpufeature.c
> > > > +++ b/arch/riscv/kernel/cpufeature.c
> > > > @@ -24,6 +24,7 @@
> > > >  #include <asm/processor.h>
> > > >  #include <asm/sbi.h>
> > > >  #include <asm/vector.h>
> > > > +#include <asm/vendor_extensions.h>
> > > >
> > > >  #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
> > > >
> > > > @@ -102,24 +103,6 @@ static bool riscv_isa_extension_check(int id)
> > > >         return true;
> > > >  }
> > > >
> > > > -#define _RISCV_ISA_EXT_DATA(_name, _id, _subset_exts, _subset_exts_size) {     \
> > > > -       .name = #_name,                                                         \
> > > > -       .property = #_name,                                                     \
> > > > -       .id = _id,                                                              \
> > > > -       .subset_ext_ids = _subset_exts,                                         \
> > > > -       .subset_ext_size = _subset_exts_size                                    \
> > > > -}
> > > > -
> > > > -#define __RISCV_ISA_EXT_DATA(_name, _id) _RISCV_ISA_EXT_DATA(_name, _id, NULL, 0)
> > > > -
> > > > -/* Used to declare pure "lasso" extension (Zk for instance) */
> > > > -#define __RISCV_ISA_EXT_BUNDLE(_name, _bundled_exts) \
> > > > -       _RISCV_ISA_EXT_DATA(_name, RISCV_ISA_EXT_INVALID, _bundled_exts, ARRAY_SIZE(_bundled_exts))
> > > > -
> > > > -/* Used to declare extensions that are a superset of other extensions (Zvbb for instance) */
> > > > -#define __RISCV_ISA_EXT_SUPERSET(_name, _id, _sub_exts) \
> > > > -       _RISCV_ISA_EXT_DATA(_name, _id, _sub_exts, ARRAY_SIZE(_sub_exts))
> > > > -
> > > >  static const unsigned int riscv_zk_bundled_exts[] = {
> > > >         RISCV_ISA_EXT_ZBKB,
> > > >         RISCV_ISA_EXT_ZBKC,
> > > > @@ -353,6 +336,21 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
> > > >                 bool ext_long = false, ext_err = false;
> > > >
> > > >                 switch (*ext) {
> > > > +               case 'x':
> > > > +               case 'X':
> > > > +                       if (acpi_disabled)
> > > > +                               pr_warn_once("Vendor extensions are ignored in riscv,isa. Use riscv,isa-extensions instead.");
> > > > +                       /*
> > > > +                        * To skip an extension, we find its end.
> > > > +                        * As multi-letter extensions must be split from other multi-letter
> > > > +                        * extensions with an "_", the end of a multi-letter extension will
> > > > +                        * either be the null character or the "_" at the start of the next
> > > > +                        * multi-letter extension.
> > > > +                        */
> > > > +                       for (; *isa && *isa != '_'; ++isa)
> > > > +                               ;
> > > > +                       ext_err = true;
> > > > +                       break;
> > > >                 case 's':
> > > >                         /*
> > > >                          * Workaround for invalid single-letter 's' & 'u' (QEMU).
> > > > @@ -368,8 +366,6 @@ static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct risc
> > > >                         }
> > > >                         fallthrough;
> > > >                 case 'S':
> > > > -               case 'x':
> > > > -               case 'X':
> > > >                 case 'z':
> > > >                 case 'Z':
> > > >                         /*
> > > > @@ -572,6 +568,59 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
> > > >                 acpi_put_table((struct acpi_table_header *)rhct);
> > > >  }
> > > >
> > > > +static void __init riscv_fill_cpu_vendor_ext(struct device_node *cpu_node, int cpu)
> > > > +{
> > > > +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> > > > +               return;
> > > > +
> > > > +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> > > > +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> > > > +
> > > > +               for (int j = 0; j < ext_list->ext_data_count; j++) {
> > > > +                       const struct riscv_isa_ext_data ext = ext_list->ext_data[j];
> > > > +                       struct riscv_isavendorinfo *isavendorinfo = &ext_list->per_hart_isa_bitmap[cpu];
> > > > +
> > > > +                       if (of_property_match_string(cpu_node, "riscv,isa-extensions",
> > > > +                                                    ext.property) < 0)
> > > > +                               continue;
> > > > +
> > > > +                       /*
> > > > +                        * Assume that subset extensions are all members of the
> > > > +                        * same vendor.
> > > > +                        */
> > > > +                       if (ext.subset_ext_size)
> > > > +                               for (int k = 0; k < ext.subset_ext_size; k++)
> > > > +                                       set_bit(ext.subset_ext_ids[k], isavendorinfo->isa);
> > > > +
> > > > +                       set_bit(ext.id, isavendorinfo->isa);
> > > > +               }
> > > > +       }
> > > > +}
> > > > +
> > > > +static void __init riscv_fill_vendor_ext_list(int cpu)
> > > > +{
> > > > +       bool first = true;
> > > > +
> > > > +       if (!IS_ENABLED(CONFIG_RISCV_ISA_VENDOR_EXT))
> > > > +               return;
> > > > +
> > > > +       for (int i = 0; i < riscv_isa_vendor_ext_list_size; i++) {
> > > > +               struct riscv_isa_vendor_ext_data_list *ext_list = riscv_isa_vendor_ext_list[i];
> > > > +
> > > > +               if (first) {
> > > > +                       bitmap_copy(ext_list->all_harts_isa_bitmap.isa,
> > > > +                                   ext_list->per_hart_isa_bitmap[cpu].isa,
> > > > +                                   RISCV_ISA_VENDOR_EXT_MAX);
> > > > +                       first = false;
> > >
> > > I think this is still not quite right. This behaves properly when
> > > called on the first cpu (let's say 0), but then we call it again with
> > > cpu 1, first gets set to true, and we clobber the old work we did for
> > > cpu 0. If we knew that cpu 0 was always called first (this looks true
> > > since both calls are within a for_each_possible_cpu() loop), and that
> > > this was only called once at boot for cpu 0 (looks true, and
> > > riscv_fill_hwcap() is __init), then it could be bool first = cpu == 0.
> >
> > Assuming that the first cpu is 0 should be safe, but to eliminate that
> > assumption we can pass in a "first" parameter into this function that
> > will only be true the first time this function is called. We also keep
> > "first = false" in this function so the copy only happens on the first
> > iteration of the first cpu.
> 
> Yeah, though then you still have to maintain that the function passing
> true as the first parameter really is the first invocation.
> 
> static bool first = true would also fix it, maybe more reliably. Are
> static locals allowed in the kernel?

That's even better! I did a search and saw many uses of static locals,
so let's go with that solution. I also tested it locally with a DT with
two CPUs that have two different vendor extensions from the same vendor
and verified that the all_hart_isa_bitmap did not contain either of the
vendor extensions.  I don't think it's possible to have an automated
test case like that in the kernel.

- Charlie

> 
> >
> > - Charlie
> >

Re: [PATCH v5 03/17] riscv: vector: Use vlenb from DT

[Charlie Jenkins]

On Fri, May 03, 2024 at 06:26:58PM +0100, Conor Dooley wrote:
> On Fri, May 03, 2024 at 10:15:16AM -0700, Charlie Jenkins wrote:
> > The DT is improperly
> > formatted since it has heterogeneous vlenb entries and has V enabled,
> > but since the user disabled V in the kernel skipping the warning is
> > reasonable.
> 
> I wouldn't go as far as "improperly formatted", as if the harts really
> do have differing vector lengths, it's correctly formatted. It's just
> not something we support in Linux.

Fair enough, not supported is a better term here.

- Charlie