[PATCH v11 00/11] Add support for SBI v0.2 and CPU hotplug

[PATCH v11 00/11] Add support for SBI v0.2 and CPU hotplug

[Atish Patra]

The Supervisor Binary Interface(SBI) specification[1] now defines a
base extension that provides extendability to add future extensions
while maintaining backward compatibility with previous versions.
The new version is defined as 0.2 and older version is marked as 0.1.

This series adds following features to RISC-V Linux.
1. Adds support for SBI v0.2
2. A Unified calling convention implementation between 0.1 and 0.2. 
3. SBI Hart state management extension (HSM)
4. Ordered booting of harts
4. CPU hotplug 

Dependencies:
The support for SBI v0.2 and HSM extension is already available in OpenSBI
master.

[1] https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc

The patches are also available in following github repositery.

Linux Kernel: https://github.com/atishp04/linux/tree/sbi_v0.2_v11

Patches 1-5 implements the SBI v0.2 and unified calling convention.
Patches 6-7 adds a cpu_ops method that allows different booting protocols
dynamically.
Patches 9-10 adds HSM extension and ordered hart booting support.
Patche  11 adds cpu hotplug support.

Changes v10->v11:
1. Addressed few nitpick comments.
2. Dropped plic patch as it is taken through IRQ tree.

Changes from v9->10:
1. Minor copyright fixes.
2. Renaming of HSM extension definitions to match the spec.
 
Changes from v8->v9:
1. Added a sliding window hart base method to support larger hart masks.
2. Added a callback to disable interrupts when cpu go offline.
3. Made the HSM extension series more modular.

Changes from v7-v8:
1. Refactored to code to have modular cpu_ops calls.
2. Refactored HSM extension from sbi.c to cpu_ops_sbi.c.
3. Fix plic driver to handle cpu hotplug.

Changes from v6-v7:
1. Rebased on v5.5
2. Fixed few compilation issues for !CONFIG_SMP and !CONFIG_RISCV_SBI
3. Added SBI HSM extension
4. Add CPU hotplug support

Changes from v5->v6
1. Fixed few compilation issues around config.
2. Fixed hart mask generation issues for RFENCE & IPI extensions.

Changes from v4->v5
1. Fixed few minor comments related to static & inline.
2. Make sure that every patch is boot tested individually.

Changes from v3->v4.
1. Rebased on for-next.
2. Fixed issuses with checkpatch --strict.
3. Unfied all IPI/fence related functions.
4. Added Hfence related SBI calls.

Changes from v2->v3.
1. Moved v0.1 extensions to a new config.
2. Added support for relacement extensions of v0.1 extensions.

Changes from v1->v2
1. Removed the legacy calling convention.
2. Moved all SBI related calls to sbi.c.
3. Moved all SBI related macros to uapi.

Atish Patra (11):
RISC-V: Mark existing SBI as 0.1 SBI.
RISC-V: Add basic support for SBI v0.2
RISC-V: Add SBI v0.2 extension definitions
RISC-V: Introduce a new config for SBI v0.1
RISC-V: Implement new SBI v0.2 extensions
RISC-V: Move relocate and few other functions out of __init
RISC-V: Add cpu_ops and modify default booting method
RISC-V: Export SBI error to linux error mapping function
RISC-V: Add SBI HSM extension definitions
RISC-V: Add supported for ordered booting method using HSM
RISC-V: Support cpu hotplug

arch/riscv/Kconfig                   |  19 +-
arch/riscv/include/asm/cpu_ops.h     |  46 +++
arch/riscv/include/asm/sbi.h         | 195 +++++----
arch/riscv/include/asm/smp.h         |  24 ++
arch/riscv/kernel/Makefile           |   6 +
arch/riscv/kernel/cpu-hotplug.c      |  87 ++++
arch/riscv/kernel/cpu_ops.c          |  46 +++
arch/riscv/kernel/cpu_ops_sbi.c      | 115 ++++++
arch/riscv/kernel/cpu_ops_spinwait.c |  43 ++
arch/riscv/kernel/head.S             | 179 +++++----
arch/riscv/kernel/sbi.c              | 575 ++++++++++++++++++++++++++-
arch/riscv/kernel/setup.c            |  24 +-
arch/riscv/kernel/smpboot.c          |  53 ++-
arch/riscv/kernel/traps.c            |   2 +-
arch/riscv/kernel/vmlinux.lds.S      |   5 +-
15 files changed, 1249 insertions(+), 170 deletions(-)
create mode 100644 arch/riscv/include/asm/cpu_ops.h
create mode 100644 arch/riscv/kernel/cpu-hotplug.c
create mode 100644 arch/riscv/kernel/cpu_ops.c
create mode 100644 arch/riscv/kernel/cpu_ops_sbi.c
create mode 100644 arch/riscv/kernel/cpu_ops_spinwait.c

--
2.25.1

[PATCH v11 01/11] RISC-V: Mark existing SBI as 0.1 SBI.

[Atish Patra]

As per the new SBI specification, current SBI implementation version
is defined as 0.1 and will be removed/replaced in future. Each of the
function call in 0.1 is defined as a separate extension which makes
easier to replace them one at a time.

Rename existing implementation to reflect that. This patch is just
a preparatory patch for SBI v0.2 and doesn't introduce any functional
changes.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/include/asm/sbi.h | 41 +++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 19 deletions(-)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 2570c1e683d3..2a637ebd7a22 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright (C) 2015 Regents of the University of California
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
  */
 
 #ifndef _ASM_RISCV_SBI_H
@@ -9,15 +10,15 @@
 #include <linux/types.h>
 
 #ifdef CONFIG_RISCV_SBI
-#define SBI_SET_TIMER 0
-#define SBI_CONSOLE_PUTCHAR 1
-#define SBI_CONSOLE_GETCHAR 2
-#define SBI_CLEAR_IPI 3
-#define SBI_SEND_IPI 4
-#define SBI_REMOTE_FENCE_I 5
-#define SBI_REMOTE_SFENCE_VMA 6
-#define SBI_REMOTE_SFENCE_VMA_ASID 7
-#define SBI_SHUTDOWN 8
+#define SBI_EXT_0_1_SET_TIMER 0x0
+#define SBI_EXT_0_1_CONSOLE_PUTCHAR 0x1
+#define SBI_EXT_0_1_CONSOLE_GETCHAR 0x2
+#define SBI_EXT_0_1_CLEAR_IPI 0x3
+#define SBI_EXT_0_1_SEND_IPI 0x4
+#define SBI_EXT_0_1_REMOTE_FENCE_I 0x5
+#define SBI_EXT_0_1_REMOTE_SFENCE_VMA 0x6
+#define SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID 0x7
+#define SBI_EXT_0_1_SHUTDOWN 0x8
 
 #define SBI_CALL(which, arg0, arg1, arg2, arg3) ({		\
 	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);	\
@@ -43,48 +44,49 @@
 
 static inline void sbi_console_putchar(int ch)
 {
-	SBI_CALL_1(SBI_CONSOLE_PUTCHAR, ch);
+	SBI_CALL_1(SBI_EXT_0_1_CONSOLE_PUTCHAR, ch);
 }
 
 static inline int sbi_console_getchar(void)
 {
-	return SBI_CALL_0(SBI_CONSOLE_GETCHAR);
+	return SBI_CALL_0(SBI_EXT_0_1_CONSOLE_GETCHAR);
 }
 
 static inline void sbi_set_timer(uint64_t stime_value)
 {
 #if __riscv_xlen == 32
-	SBI_CALL_2(SBI_SET_TIMER, stime_value, stime_value >> 32);
+	SBI_CALL_2(SBI_EXT_0_1_SET_TIMER, stime_value,
+		   stime_value >> 32);
 #else
-	SBI_CALL_1(SBI_SET_TIMER, stime_value);
+	SBI_CALL_1(SBI_EXT_0_1_SET_TIMER, stime_value);
 #endif
 }
 
 static inline void sbi_shutdown(void)
 {
-	SBI_CALL_0(SBI_SHUTDOWN);
+	SBI_CALL_0(SBI_EXT_0_1_SHUTDOWN);
 }
 
 static inline void sbi_clear_ipi(void)
 {
-	SBI_CALL_0(SBI_CLEAR_IPI);
+	SBI_CALL_0(SBI_EXT_0_1_CLEAR_IPI);
 }
 
 static inline void sbi_send_ipi(const unsigned long *hart_mask)
 {
-	SBI_CALL_1(SBI_SEND_IPI, hart_mask);
+	SBI_CALL_1(SBI_EXT_0_1_SEND_IPI, hart_mask);
 }
 
 static inline void sbi_remote_fence_i(const unsigned long *hart_mask)
 {
-	SBI_CALL_1(SBI_REMOTE_FENCE_I, hart_mask);
+	SBI_CALL_1(SBI_EXT_0_1_REMOTE_FENCE_I, hart_mask);
 }
 
 static inline void sbi_remote_sfence_vma(const unsigned long *hart_mask,
 					 unsigned long start,
 					 unsigned long size)
 {
-	SBI_CALL_3(SBI_REMOTE_SFENCE_VMA, hart_mask, start, size);
+	SBI_CALL_3(SBI_EXT_0_1_REMOTE_SFENCE_VMA, hart_mask, start, size);
 }
 
 static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
@@ -92,7 +94,8 @@ static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
 					      unsigned long size,
 					      unsigned long asid)
 {
-	SBI_CALL_4(SBI_REMOTE_SFENCE_VMA_ASID, hart_mask, start, size, asid);
+	SBI_CALL_4(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID, hart_mask,
+		   start, size, asid);
 }
 #else /* CONFIG_RISCV_SBI */
 /* stubs for code that is only reachable under IS_ENABLED(CONFIG_RISCV_SBI): */
-- 
2.25.1

[PATCH v11 02/11] RISC-V: Add basic support for SBI v0.2

[Atish Patra]

The SBI v0.2 introduces a base extension which is backward compatible
with v0.1. Implement all helper functions and minimum required SBI
calls from v0.2 for now. All other base extension function will be
added later as per need.
As v0.2 calling convention is backward compatible with v0.1, remove
the v0.1 helper functions and just use v0.2 calling convention.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/include/asm/sbi.h | 139 ++++++++++----------
 arch/riscv/kernel/sbi.c      | 243 ++++++++++++++++++++++++++++++++++-
 arch/riscv/kernel/setup.c    |   5 +
 3 files changed, 314 insertions(+), 73 deletions(-)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 2a637ebd7a22..5b7b91c7e7e6 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -10,92 +10,88 @@
 #include <linux/types.h>
 
 #ifdef CONFIG_RISCV_SBI
-#define SBI_EXT_0_1_SET_TIMER 0x0
-#define SBI_EXT_0_1_CONSOLE_PUTCHAR 0x1
-#define SBI_EXT_0_1_CONSOLE_GETCHAR 0x2
-#define SBI_EXT_0_1_CLEAR_IPI 0x3
-#define SBI_EXT_0_1_SEND_IPI 0x4
-#define SBI_EXT_0_1_REMOTE_FENCE_I 0x5
-#define SBI_EXT_0_1_REMOTE_SFENCE_VMA 0x6
-#define SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID 0x7
-#define SBI_EXT_0_1_SHUTDOWN 0x8
+enum sbi_ext_id {
+	SBI_EXT_0_1_SET_TIMER = 0x0,
+	SBI_EXT_0_1_CONSOLE_PUTCHAR = 0x1,
+	SBI_EXT_0_1_CONSOLE_GETCHAR = 0x2,
+	SBI_EXT_0_1_CLEAR_IPI = 0x3,
+	SBI_EXT_0_1_SEND_IPI = 0x4,
+	SBI_EXT_0_1_REMOTE_FENCE_I = 0x5,
+	SBI_EXT_0_1_REMOTE_SFENCE_VMA = 0x6,
+	SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID = 0x7,
+	SBI_EXT_0_1_SHUTDOWN = 0x8,
+	SBI_EXT_BASE = 0x10,
+};
 
-#define SBI_CALL(which, arg0, arg1, arg2, arg3) ({		\
-	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);	\
-	register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);	\
-	register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);	\
-	register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);	\
-	register uintptr_t a7 asm ("a7") = (uintptr_t)(which);	\
-	asm volatile ("ecall"					\
-		      : "+r" (a0)				\
-		      : "r" (a1), "r" (a2), "r" (a3), "r" (a7)	\
-		      : "memory");				\
-	a0;							\
-})
+enum sbi_ext_base_fid {
+	SBI_EXT_BASE_GET_SPEC_VERSION = 0,
+	SBI_EXT_BASE_GET_IMP_ID,
+	SBI_EXT_BASE_GET_IMP_VERSION,
+	SBI_EXT_BASE_PROBE_EXT,
+	SBI_EXT_BASE_GET_MVENDORID,
+	SBI_EXT_BASE_GET_MARCHID,
+	SBI_EXT_BASE_GET_MIMPID,
+};
 
-/* Lazy implementations until SBI is finalized */
-#define SBI_CALL_0(which) SBI_CALL(which, 0, 0, 0, 0)
-#define SBI_CALL_1(which, arg0) SBI_CALL(which, arg0, 0, 0, 0)
-#define SBI_CALL_2(which, arg0, arg1) SBI_CALL(which, arg0, arg1, 0, 0)
-#define SBI_CALL_3(which, arg0, arg1, arg2) \
-		SBI_CALL(which, arg0, arg1, arg2, 0)
-#define SBI_CALL_4(which, arg0, arg1, arg2, arg3) \
-		SBI_CALL(which, arg0, arg1, arg2, arg3)
+#define SBI_SPEC_VERSION_DEFAULT	0x1
+#define SBI_SPEC_VERSION_MAJOR_SHIFT	24
+#define SBI_SPEC_VERSION_MAJOR_MASK	0x7f
+#define SBI_SPEC_VERSION_MINOR_MASK	0xffffff
 
-static inline void sbi_console_putchar(int ch)
-{
-	SBI_CALL_1(SBI_EXT_0_1_CONSOLE_PUTCHAR, ch);
-}
+/* SBI return error codes */
+#define SBI_SUCCESS		0
+#define SBI_ERR_FAILURE		-1
+#define SBI_ERR_NOT_SUPPORTED	-2
+#define SBI_ERR_INVALID_PARAM	-3
+#define SBI_ERR_DENIED		-4
+#define SBI_ERR_INVALID_ADDRESS	-5
 
-static inline int sbi_console_getchar(void)
-{
-	return SBI_CALL_0(SBI_EXT_0_1_CONSOLE_GETCHAR);
-}
+extern unsigned long sbi_spec_version;
+struct sbiret {
+	long error;
+	long value;
+};
 
-static inline void sbi_set_timer(uint64_t stime_value)
-{
-#if __riscv_xlen == 32
-	SBI_CALL_2(SBI_EXT_0_1_SET_TIMER, stime_value,
-		   stime_value >> 32);
-#else
-	SBI_CALL_1(SBI_EXT_0_1_SET_TIMER, stime_value);
-#endif
-}
-
-static inline void sbi_shutdown(void)
-{
-	SBI_CALL_0(SBI_EXT_0_1_SHUTDOWN);
-}
+int sbi_init(void);
+struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
+			unsigned long arg1, unsigned long arg2,
+			unsigned long arg3, unsigned long arg4,
+			unsigned long arg5);
 
-static inline void sbi_clear_ipi(void)
-{
-	SBI_CALL_0(SBI_EXT_0_1_CLEAR_IPI);
-}
+void sbi_console_putchar(int ch);
+int sbi_console_getchar(void);
+void sbi_set_timer(uint64_t stime_value);
+void sbi_shutdown(void);
+void sbi_clear_ipi(void);
+void sbi_send_ipi(const unsigned long *hart_mask);
+void sbi_remote_fence_i(const unsigned long *hart_mask);
+void sbi_remote_sfence_vma(const unsigned long *hart_mask,
+			   unsigned long start,
+			   unsigned long size);
 
-static inline void sbi_send_ipi(const unsigned long *hart_mask)
-{
-	SBI_CALL_1(SBI_EXT_0_1_SEND_IPI, hart_mask);
-}
+void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
+				unsigned long start,
+				unsigned long size,
+				unsigned long asid);
+int sbi_probe_extension(int ext);
 
-static inline void sbi_remote_fence_i(const unsigned long *hart_mask)
+/* Check if current SBI specification version is 0.1 or not */
+static inline int sbi_spec_is_0_1(void)
 {
-	SBI_CALL_1(SBI_EXT_0_1_REMOTE_FENCE_I, hart_mask);
+	return (sbi_spec_version == SBI_SPEC_VERSION_DEFAULT) ? 1 : 0;
 }
 
-static inline void sbi_remote_sfence_vma(const unsigned long *hart_mask,
-					 unsigned long start,
-					 unsigned long size)
+/* Get the major version of SBI */
+static inline unsigned long sbi_major_version(void)
 {
-	SBI_CALL_3(SBI_EXT_0_1_REMOTE_SFENCE_VMA, hart_mask, start, size);
+	return (sbi_spec_version >> SBI_SPEC_VERSION_MAJOR_SHIFT) &
+		SBI_SPEC_VERSION_MAJOR_MASK;
 }
 
-static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
-					      unsigned long start,
-					      unsigned long size,
-					      unsigned long asid)
+/* Get the minor version of SBI */
+static inline unsigned long sbi_minor_version(void)
 {
-	SBI_CALL_4(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID, hart_mask,
-		   start, size, asid);
+	return sbi_spec_version & SBI_SPEC_VERSION_MINOR_MASK;
 }
 #else /* CONFIG_RISCV_SBI */
 /* stubs for code that is only reachable under IS_ENABLED(CONFIG_RISCV_SBI): */
@@ -103,5 +99,6 @@ void sbi_set_timer(uint64_t stime_value);
 void sbi_clear_ipi(void);
 void sbi_send_ipi(const unsigned long *hart_mask);
 void sbi_remote_fence_i(const unsigned long *hart_mask);
+void sbi_init(void);
 #endif /* CONFIG_RISCV_SBI */
 #endif /* _ASM_RISCV_SBI_H */
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index f6c7c3e82d28..4aee0b49df3c 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -1,17 +1,256 @@
 // SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SBI initialilization and all extension implementation.
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ */
 
 #include <linux/init.h>
 #include <linux/pm.h>
 #include <asm/sbi.h>
 
+/* default SBI version is 0.1 */
+unsigned long sbi_spec_version = SBI_SPEC_VERSION_DEFAULT;
+EXPORT_SYMBOL(sbi_spec_version);
+
+struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
+			unsigned long arg1, unsigned long arg2,
+			unsigned long arg3, unsigned long arg4,
+			unsigned long arg5)
+{
+	struct sbiret ret;
+
+	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
+	register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
+	register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
+	register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);
+	register uintptr_t a4 asm ("a4") = (uintptr_t)(arg4);
+	register uintptr_t a5 asm ("a5") = (uintptr_t)(arg5);
+	register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);
+	register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);
+	asm volatile ("ecall"
+		      : "+r" (a0), "+r" (a1)
+		      : "r" (a2), "r" (a3), "r" (a4), "r" (a5), "r" (a6), "r" (a7)
+		      : "memory");
+	ret.error = a0;
+	ret.value = a1;
+
+	return ret;
+}
+EXPORT_SYMBOL(sbi_ecall);
+
+static int sbi_err_map_linux_errno(int err)
+{
+	switch (err) {
+	case SBI_SUCCESS:
+		return 0;
+	case SBI_ERR_DENIED:
+		return -EPERM;
+	case SBI_ERR_INVALID_PARAM:
+		return -EINVAL;
+	case SBI_ERR_INVALID_ADDRESS:
+		return -EFAULT;
+	case SBI_ERR_NOT_SUPPORTED:
+	case SBI_ERR_FAILURE:
+	default:
+		return -ENOTSUPP;
+	};
+}
+
+/**
+ * sbi_console_putchar() - Writes given character to the console device.
+ * @ch: The data to be written to the console.
+ *
+ * Return: None
+ */
+void sbi_console_putchar(int ch)
+{
+	sbi_ecall(SBI_EXT_0_1_CONSOLE_PUTCHAR, 0, ch, 0, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(sbi_console_putchar);
+
+/**
+ * sbi_console_getchar() - Reads a byte from console device.
+ *
+ * Returns the value read from console.
+ */
+int sbi_console_getchar(void)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_0_1_CONSOLE_GETCHAR, 0, 0, 0, 0, 0, 0, 0);
+
+	return ret.error;
+}
+EXPORT_SYMBOL(sbi_console_getchar);
+
+/**
+ * sbi_set_timer() - Program the timer for next timer event.
+ * @stime_value: The value after which next timer event should fire.
+ *
+ * Return: None
+ */
+void sbi_set_timer(uint64_t stime_value)
+{
+#if __riscv_xlen == 32
+	sbi_ecall(SBI_EXT_0_1_SET_TIMER, 0, stime_value,
+		  stime_value >> 32, 0, 0, 0, 0);
+#else
+	sbi_ecall(SBI_EXT_0_1_SET_TIMER, 0, stime_value, 0, 0, 0, 0, 0);
+#endif
+}
+EXPORT_SYMBOL(sbi_set_timer);
+
+/**
+ * sbi_shutdown() - Remove all the harts from executing supervisor code.
+ *
+ * Return: None
+ */
+void sbi_shutdown(void)
+{
+	sbi_ecall(SBI_EXT_0_1_SHUTDOWN, 0, 0, 0, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(sbi_shutdown);
+
+/**
+ * sbi_clear_ipi() - Clear any pending IPIs for the calling hart.
+ *
+ * Return: None
+ */
+void sbi_clear_ipi(void)
+{
+	sbi_ecall(SBI_EXT_0_1_CLEAR_IPI, 0, 0, 0, 0, 0, 0, 0);
+}
+
+/**
+ * sbi_send_ipi() - Send an IPI to any hart.
+ * @hart_mask: A cpu mask containing all the target harts.
+ *
+ * Return: None
+ */
+void sbi_send_ipi(const unsigned long *hart_mask)
+{
+	sbi_ecall(SBI_EXT_0_1_SEND_IPI, 0, (unsigned long)hart_mask,
+		  0, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(sbi_send_ipi);
+
+/**
+ * sbi_remote_fence_i() - Execute FENCE.I instruction on given remote harts.
+ * @hart_mask: A cpu mask containing all the target harts.
+ *
+ * Return: None
+ */
+void sbi_remote_fence_i(const unsigned long *hart_mask)
+{
+	sbi_ecall(SBI_EXT_0_1_REMOTE_FENCE_I, 0, (unsigned long)hart_mask,
+		  0, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(sbi_remote_fence_i);
+
+/**
+ * sbi_remote_sfence_vma() - Execute SFENCE.VMA instructions on given remote
+ *			     harts for the specified virtual address range.
+ * @hart_mask: A cpu mask containing all the target harts.
+ * @start: Start of the virtual address
+ * @size: Total size of the virtual address range.
+ *
+ * Return: None
+ */
+void sbi_remote_sfence_vma(const unsigned long *hart_mask,
+			   unsigned long start,
+			   unsigned long size)
+{
+	sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA, 0,
+		  (unsigned long)hart_mask, start, size, 0, 0, 0);
+}
+EXPORT_SYMBOL(sbi_remote_sfence_vma);
+
+/**
+ * sbi_remote_sfence_vma_asid() - Execute SFENCE.VMA instructions on given
+ * remote harts for a virtual address range belonging to a specific ASID.
+ *
+ * @hart_mask: A cpu mask containing all the target harts.
+ * @start: Start of the virtual address
+ * @size: Total size of the virtual address range.
+ * @asid: The value of address space identifier (ASID).
+ *
+ * Return: None
+ */
+void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
+				unsigned long start,
+				unsigned long size,
+				unsigned long asid)
+{
+	sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID, 0,
+		  (unsigned long)hart_mask, start, size, asid, 0, 0);
+}
+EXPORT_SYMBOL(sbi_remote_sfence_vma_asid);
+
+/**
+ * sbi_probe_extension() - Check if an SBI extension ID is supported or not.
+ * @extid: The extension ID to be probed.
+ *
+ * Return: Extension specific nonzero value f yes, -ENOTSUPP otherwise.
+ */
+int sbi_probe_extension(int extid)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_BASE, SBI_EXT_BASE_PROBE_EXT, extid,
+			0, 0, 0, 0, 0);
+	if (!ret.error)
+		if (ret.value)
+			return ret.value;
+
+	return -ENOTSUPP;
+}
+EXPORT_SYMBOL(sbi_probe_extension);
+
+static long __sbi_base_ecall(int fid)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_BASE, fid, 0, 0, 0, 0, 0, 0);
+	if (!ret.error)
+		return ret.value;
+	else
+		return sbi_err_map_linux_errno(ret.error);
+}
+
+static inline long sbi_get_spec_version(void)
+{
+	return __sbi_base_ecall(SBI_EXT_BASE_GET_SPEC_VERSION);
+}
+
+static inline long sbi_get_firmware_id(void)
+{
+	return __sbi_base_ecall(SBI_EXT_BASE_GET_IMP_ID);
+}
+
+static inline long sbi_get_firmware_version(void)
+{
+	return __sbi_base_ecall(SBI_EXT_BASE_GET_IMP_VERSION);
+}
+
 static void sbi_power_off(void)
 {
 	sbi_shutdown();
 }
 
-static int __init sbi_init(void)
+int __init sbi_init(void)
 {
+	int ret;
+
 	pm_power_off = sbi_power_off;
+	ret = sbi_get_spec_version();
+	if (ret > 0)
+		sbi_spec_version = ret;
+
+	pr_info("SBI specification v%lu.%lu detected\n",
+		sbi_major_version(), sbi_minor_version());
+	if (!sbi_spec_is_0_1())
+		pr_info("SBI implementation ID=0x%lx Version=0x%lx\n",
+			sbi_get_firmware_id(), sbi_get_firmware_version());
 	return 0;
 }
-early_initcall(sbi_init);
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 0a6d415b0a5a..44ac4ddf60ab 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -22,6 +22,7 @@
 #include <asm/sections.h>
 #include <asm/pgtable.h>
 #include <asm/smp.h>
+#include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/thread_info.h>
 #include <asm/kasan.h>
@@ -79,6 +80,10 @@ void __init setup_arch(char **cmdline_p)
 	kasan_init();
 #endif
 
+#if IS_ENABLED(CONFIG_RISCV_SBI)
+	sbi_init();
+#endif
+
 #ifdef CONFIG_SMP
 	setup_smp();
 #endif
-- 
2.25.1

[PATCH v11 03/11] RISC-V: Add SBI v0.2 extension definitions

[Atish Patra]

Few v0.1 SBI calls are being replaced by new SBI calls that follows
v0.2 calling convention.

This patch just defines these new extensions.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/include/asm/sbi.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 5b7b91c7e7e6..f68b6ed10a18 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -21,6 +21,9 @@ enum sbi_ext_id {
 	SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID = 0x7,
 	SBI_EXT_0_1_SHUTDOWN = 0x8,
 	SBI_EXT_BASE = 0x10,
+	SBI_EXT_TIME = 0x54494D45,
+	SBI_EXT_IPI = 0x735049,
+	SBI_EXT_RFENCE = 0x52464E43,
 };
 
 enum sbi_ext_base_fid {
@@ -33,6 +36,24 @@ enum sbi_ext_base_fid {
 	SBI_EXT_BASE_GET_MIMPID,
 };
 
+enum sbi_ext_time_fid {
+	SBI_EXT_TIME_SET_TIMER = 0,
+};
+
+enum sbi_ext_ipi_fid {
+	SBI_EXT_IPI_SEND_IPI = 0,
+};
+
+enum sbi_ext_rfence_fid {
+	SBI_EXT_RFENCE_REMOTE_FENCE_I = 0,
+	SBI_EXT_RFENCE_REMOTE_SFENCE_VMA,
+	SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID,
+	SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA,
+	SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID,
+	SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA,
+	SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID,
+};
+
 #define SBI_SPEC_VERSION_DEFAULT	0x1
 #define SBI_SPEC_VERSION_MAJOR_SHIFT	24
 #define SBI_SPEC_VERSION_MAJOR_MASK	0x7f
-- 
2.25.1

[PATCH v11 04/11] RISC-V: Introduce a new config for SBI v0.1

[Atish Patra]

We now have SBI v0.2 which is more scalable and extendable to handle
future needs for RISC-V supervisor interfaces.

Introduce a new config and move all SBI v0.1 code under that config.
This allows to implement the new replacement SBI extensions cleanly
and remove v0.1 extensions easily in future. Currently, the config
is enabled by default. Once all M-mode software, with v0.1, is no
longer in use, this config option and all relevant code can be easily
removed.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/Kconfig           |   7 ++
 arch/riscv/include/asm/sbi.h |   2 +
 arch/riscv/kernel/sbi.c      | 132 +++++++++++++++++++++++++++++------
 3 files changed, 118 insertions(+), 23 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 1a3b5a5276be..20c6191399ea 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -308,6 +308,13 @@ config SECCOMP
 	  and the task is only allowed to execute a few safe syscalls
 	  defined by each seccomp mode.
 
+config RISCV_SBI_V01
+	bool "SBI v0.1 support"
+	default y
+	depends on RISCV_SBI
+	help
+	  This config allows kernel to use SBI v0.1 APIs. This will be
+	  deprecated in future once legacy M-mode software are no longer in use.
 endmenu
 
 menu "Boot options"
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index f68b6ed10a18..d712b61f8dbc 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -11,6 +11,7 @@
 
 #ifdef CONFIG_RISCV_SBI
 enum sbi_ext_id {
+#ifdef CONFIG_RISCV_SBI_V01
 	SBI_EXT_0_1_SET_TIMER = 0x0,
 	SBI_EXT_0_1_CONSOLE_PUTCHAR = 0x1,
 	SBI_EXT_0_1_CONSOLE_GETCHAR = 0x2,
@@ -20,6 +21,7 @@ enum sbi_ext_id {
 	SBI_EXT_0_1_REMOTE_SFENCE_VMA = 0x6,
 	SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID = 0x7,
 	SBI_EXT_0_1_SHUTDOWN = 0x8,
+#endif
 	SBI_EXT_BASE = 0x10,
 	SBI_EXT_TIME = 0x54494D45,
 	SBI_EXT_IPI = 0x735049,
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 4aee0b49df3c..1368da62ec82 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -13,6 +13,12 @@
 unsigned long sbi_spec_version = SBI_SPEC_VERSION_DEFAULT;
 EXPORT_SYMBOL(sbi_spec_version);
 
+static void (*__sbi_set_timer)(uint64_t stime);
+static int (*__sbi_send_ipi)(const unsigned long *hart_mask);
+static int (*__sbi_rfence)(int fid, const unsigned long *hart_mask,
+			   unsigned long start, unsigned long size,
+			   unsigned long arg4, unsigned long arg5);
+
 struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
 			unsigned long arg1, unsigned long arg2,
 			unsigned long arg3, unsigned long arg4,
@@ -57,6 +63,7 @@ static int sbi_err_map_linux_errno(int err)
 	};
 }
 
+#ifdef CONFIG_RISCV_SBI_V01
 /**
  * sbi_console_putchar() - Writes given character to the console device.
  * @ch: The data to be written to the console.
@@ -85,12 +92,34 @@ int sbi_console_getchar(void)
 EXPORT_SYMBOL(sbi_console_getchar);
 
 /**
- * sbi_set_timer() - Program the timer for next timer event.
+ * sbi_shutdown() - Remove all the harts from executing supervisor code.
+ *
+ * Return: None
+ */
+void sbi_shutdown(void)
+{
+	sbi_ecall(SBI_EXT_0_1_SHUTDOWN, 0, 0, 0, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(sbi_set_timer);
+
+/**
+ * sbi_clear_ipi() - Clear any pending IPIs for the calling hart.
+ *
+ * Return: None
+ */
+void sbi_clear_ipi(void)
+{
+	sbi_ecall(SBI_EXT_0_1_CLEAR_IPI, 0, 0, 0, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(sbi_shutdown);
+
+/**
+ * sbi_set_timer_v01() - Program the timer for next timer event.
  * @stime_value: The value after which next timer event should fire.
  *
  * Return: None
  */
-void sbi_set_timer(uint64_t stime_value)
+static void __sbi_set_timer_v01(uint64_t stime_value)
 {
 #if __riscv_xlen == 32
 	sbi_ecall(SBI_EXT_0_1_SET_TIMER, 0, stime_value,
@@ -99,27 +128,78 @@ void sbi_set_timer(uint64_t stime_value)
 	sbi_ecall(SBI_EXT_0_1_SET_TIMER, 0, stime_value, 0, 0, 0, 0, 0);
 #endif
 }
-EXPORT_SYMBOL(sbi_set_timer);
 
-/**
- * sbi_shutdown() - Remove all the harts from executing supervisor code.
- *
- * Return: None
- */
-void sbi_shutdown(void)
+static int __sbi_send_ipi_v01(const unsigned long *hart_mask)
 {
-	sbi_ecall(SBI_EXT_0_1_SHUTDOWN, 0, 0, 0, 0, 0, 0, 0);
+	sbi_ecall(SBI_EXT_0_1_SEND_IPI, 0, (unsigned long)hart_mask,
+		  0, 0, 0, 0, 0);
+	return 0;
 }
-EXPORT_SYMBOL(sbi_shutdown);
+
+static int __sbi_rfence_v01(int fid, const unsigned long *hart_mask,
+			    unsigned long start, unsigned long size,
+			    unsigned long arg4, unsigned long arg5)
+{
+	int result = 0;
+
+	/* v0.2 function IDs are equivalent to v0.1 extension IDs */
+	switch (fid) {
+	case SBI_EXT_RFENCE_REMOTE_FENCE_I:
+		sbi_ecall(SBI_EXT_0_1_REMOTE_FENCE_I, 0,
+			  (unsigned long)hart_mask, 0, 0, 0, 0, 0);
+		break;
+	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
+		sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA, 0,
+			  (unsigned long)hart_mask, start, size,
+			  0, 0, 0);
+		break;
+	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
+		sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID, 0,
+			  (unsigned long)hart_mask, start, size,
+			  arg4, 0, 0);
+		break;
+	default:
+		pr_err("SBI call [%d]not supported in SBI v0.1\n", fid);
+		result = -EINVAL;
+	}
+
+	return result;
+}
+#else
+static void __sbi_set_timer_v01(uint64_t stime_value)
+{
+	pr_warn("Timer extension is not available in SBI v%lu.%lu\n",
+		sbi_major_version(), sbi_minor_version());
+}
+
+static int __sbi_send_ipi_v01(const unsigned long *hart_mask)
+{
+	pr_warn("IPI extension is not available in SBI v%lu.%lu\n",
+		sbi_major_version(), sbi_minor_version());
+
+	return 0;
+}
+
+static int __sbi_rfence_v01(int fid, const unsigned long *hart_mask,
+			    unsigned long start, unsigned long size,
+			    unsigned long arg4, unsigned long arg5)
+{
+	pr_warn("remote fence extension is not available in SBI v%lu.%lu\n",
+		sbi_major_version(), sbi_minor_version());
+
+	return 0;
+}
+#endif /* CONFIG_RISCV_SBI_V01 */
 
 /**
- * sbi_clear_ipi() - Clear any pending IPIs for the calling hart.
+ * sbi_set_timer() - Program the timer for next timer event.
+ * @stime_value: The value after which next timer event should fire.
  *
  * Return: None
  */
-void sbi_clear_ipi(void)
+void sbi_set_timer(uint64_t stime_value)
 {
-	sbi_ecall(SBI_EXT_0_1_CLEAR_IPI, 0, 0, 0, 0, 0, 0, 0);
+	__sbi_set_timer(stime_value);
 }
 
 /**
@@ -130,8 +210,7 @@ void sbi_clear_ipi(void)
  */
 void sbi_send_ipi(const unsigned long *hart_mask)
 {
-	sbi_ecall(SBI_EXT_0_1_SEND_IPI, 0, (unsigned long)hart_mask,
-		  0, 0, 0, 0, 0);
+	__sbi_send_ipi(hart_mask);
 }
 EXPORT_SYMBOL(sbi_send_ipi);
 
@@ -143,8 +222,8 @@ EXPORT_SYMBOL(sbi_send_ipi);
  */
 void sbi_remote_fence_i(const unsigned long *hart_mask)
 {
-	sbi_ecall(SBI_EXT_0_1_REMOTE_FENCE_I, 0, (unsigned long)hart_mask,
-		  0, 0, 0, 0, 0);
+	__sbi_rfence(SBI_EXT_RFENCE_REMOTE_FENCE_I,
+		     hart_mask, 0, 0, 0, 0);
 }
 EXPORT_SYMBOL(sbi_remote_fence_i);
 
@@ -161,8 +240,8 @@ void sbi_remote_sfence_vma(const unsigned long *hart_mask,
 			   unsigned long start,
 			   unsigned long size)
 {
-	sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA, 0,
-		  (unsigned long)hart_mask, start, size, 0, 0, 0);
+	__sbi_rfence(SBI_EXT_RFENCE_REMOTE_SFENCE_VMA,
+		     hart_mask, start, size, 0, 0);
 }
 EXPORT_SYMBOL(sbi_remote_sfence_vma);
 
@@ -182,8 +261,8 @@ void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
 				unsigned long size,
 				unsigned long asid)
 {
-	sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID, 0,
-		  (unsigned long)hart_mask, start, size, asid, 0, 0);
+	__sbi_rfence(SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID,
+		     hart_mask, start, size, asid, 0);
 }
 EXPORT_SYMBOL(sbi_remote_sfence_vma_asid);
 
@@ -249,8 +328,15 @@ int __init sbi_init(void)
 
 	pr_info("SBI specification v%lu.%lu detected\n",
 		sbi_major_version(), sbi_minor_version());
-	if (!sbi_spec_is_0_1())
+
+	if (!sbi_spec_is_0_1()) {
 		pr_info("SBI implementation ID=0x%lx Version=0x%lx\n",
 			sbi_get_firmware_id(), sbi_get_firmware_version());
+	}
+
+	__sbi_set_timer = __sbi_set_timer_v01;
+	__sbi_send_ipi	= __sbi_send_ipi_v01;
+	__sbi_rfence	= __sbi_rfence_v01;
+
 	return 0;
 }
-- 
2.25.1

[PATCH v11 05/11] RISC-V: Implement new SBI v0.2 extensions

[Atish Patra]

Few v0.1 SBI calls are being replaced by new SBI calls that follows v0.2
calling convention.

Implement the replacement extensions and few additional new SBI function calls
that makes way for a better SBI interface in future.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/include/asm/sbi.h |  14 ++
 arch/riscv/include/asm/smp.h |   7 +
 arch/riscv/kernel/sbi.c      | 253 ++++++++++++++++++++++++++++++++++-
 3 files changed, 270 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index d712b61f8dbc..29ce2c494386 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -96,6 +96,20 @@ void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
 				unsigned long start,
 				unsigned long size,
 				unsigned long asid);
+int sbi_remote_hfence_gvma(const unsigned long *hart_mask,
+			   unsigned long start,
+			   unsigned long size);
+int sbi_remote_hfence_gvma_vmid(const unsigned long *hart_mask,
+				unsigned long start,
+				unsigned long size,
+				unsigned long vmid);
+int sbi_remote_hfence_vvma(const unsigned long *hart_mask,
+			   unsigned long start,
+			   unsigned long size);
+int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask,
+				unsigned long start,
+				unsigned long size,
+				unsigned long asid);
 int sbi_probe_extension(int ext);
 
 /* Check if current SBI specification version is 0.1 or not */
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index a83451d73a4e..023f74fb8b3b 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -61,5 +61,12 @@ static inline unsigned long cpuid_to_hartid_map(int cpu)
 	return boot_cpu_hartid;
 }
 
+static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
+					      struct cpumask *out)
+{
+	cpumask_clear(out);
+	cpumask_set_cpu(boot_cpu_hartid, out);
+}
+
 #endif /* CONFIG_SMP */
 #endif /* _ASM_RISCV_SMP_H */
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 1368da62ec82..1cc0052e1b63 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -8,6 +8,7 @@
 #include <linux/init.h>
 #include <linux/pm.h>
 #include <asm/sbi.h>
+#include <asm/smp.h>
 
 /* default SBI version is 0.1 */
 unsigned long sbi_spec_version = SBI_SPEC_VERSION_DEFAULT;
@@ -191,6 +192,153 @@ static int __sbi_rfence_v01(int fid, const unsigned long *hart_mask,
 }
 #endif /* CONFIG_RISCV_SBI_V01 */
 
+static void __sbi_set_timer_v02(uint64_t stime_value)
+{
+#if __riscv_xlen == 32
+	sbi_ecall(SBI_EXT_TIME, SBI_EXT_TIME_SET_TIMER, stime_value,
+		  stime_value >> 32, 0, 0, 0, 0);
+#else
+	sbi_ecall(SBI_EXT_TIME, SBI_EXT_TIME_SET_TIMER, stime_value, 0,
+		  0, 0, 0, 0);
+#endif
+}
+
+static int __sbi_send_ipi_v02(const unsigned long *hart_mask)
+{
+	unsigned long hartid, hmask_val, hbase;
+	struct cpumask tmask;
+	struct sbiret ret = {0};
+	int result;
+
+	if (!hart_mask || !(*hart_mask)) {
+		riscv_cpuid_to_hartid_mask(cpu_online_mask, &tmask);
+		hart_mask = cpumask_bits(&tmask);
+	}
+
+	hmask_val = 0;
+	hbase = 0;
+	for_each_set_bit(hartid, hart_mask, NR_CPUS) {
+		if (hmask_val && ((hbase + BITS_PER_LONG) <= hartid)) {
+			ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI,
+					hmask_val, hbase, 0, 0, 0, 0);
+			if (ret.error)
+				goto ecall_failed;
+			hmask_val = 0;
+			hbase = 0;
+		}
+		if (!hmask_val)
+			hbase = hartid;
+		hmask_val |= 1UL << (hartid - hbase);
+	}
+
+	if (hmask_val) {
+		ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI,
+				hmask_val, hbase, 0, 0, 0, 0);
+		if (ret.error)
+			goto ecall_failed;
+	}
+
+	return 0;
+
+ecall_failed:
+	result = sbi_err_map_linux_errno(ret.error);
+	pr_err("%s: hbase = [%lu] hmask = [0x%lx] failed (error [%d])\n",
+	       __func__, hbase, hmask_val, result);
+	return result;
+}
+
+static int __sbi_rfence_v02_call(unsigned long fid, unsigned long hmask_val,
+				 unsigned long hbase, unsigned long start,
+				 unsigned long size, unsigned long arg4,
+				 unsigned long arg5)
+{
+	struct sbiret ret = {0};
+	int ext = SBI_EXT_RFENCE;
+	int result = 0;
+
+	switch (fid) {
+	case SBI_EXT_RFENCE_REMOTE_FENCE_I:
+		ret = sbi_ecall(ext, fid, hmask_val, hbase, 0, 0, 0, 0);
+		break;
+	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
+		ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
+				size, 0, 0);
+		break;
+	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
+		ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
+				size, arg4, 0);
+		break;
+
+	case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA:
+		ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
+				size, 0, 0);
+		break;
+	case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID:
+		ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
+				size, arg4, 0);
+		break;
+	case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA:
+		ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
+				size, 0, 0);
+		break;
+	case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID:
+		ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
+				size, arg4, 0);
+		break;
+	default:
+		pr_err("unknown function ID [%lu] for SBI extension [%d]\n",
+		       fid, ext);
+		result = -EINVAL;
+	}
+
+	if (ret.error) {
+		result = sbi_err_map_linux_errno(ret.error);
+		pr_err("%s: hbase = [%lu] hmask = [0x%lx] failed (error [%d])\n",
+		       __func__, hbase, hmask_val, result);
+	}
+
+	return result;
+}
+
+static int __sbi_rfence_v02(int fid, const unsigned long *hart_mask,
+			    unsigned long start, unsigned long size,
+			    unsigned long arg4, unsigned long arg5)
+{
+	unsigned long hmask_val, hartid, hbase;
+	struct cpumask tmask;
+	int result;
+
+	if (!hart_mask || !(*hart_mask)) {
+		riscv_cpuid_to_hartid_mask(cpu_online_mask, &tmask);
+		hart_mask = cpumask_bits(&tmask);
+	}
+
+	hmask_val = 0;
+	hbase = 0;
+	for_each_set_bit(hartid, hart_mask, NR_CPUS) {
+		if (hmask_val && ((hbase + BITS_PER_LONG) <= hartid)) {
+			result = __sbi_rfence_v02_call(fid, hmask_val, hbase,
+						       start, size, arg4, arg5);
+			if (result)
+				return result;
+			hmask_val = 0;
+			hbase = 0;
+		}
+		if (!hmask_val)
+			hbase = hartid;
+		hmask_val |= 1UL << (hartid - hbase);
+	}
+
+	if (hmask_val) {
+		result = __sbi_rfence_v02_call(fid, hmask_val, hbase,
+					       start, size, arg4, arg5);
+		if (result)
+			return result;
+	}
+
+	return 0;
+}
+
 /**
  * sbi_set_timer() - Program the timer for next timer event.
  * @stime_value: The value after which next timer event should fire.
@@ -266,6 +414,85 @@ void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
 }
 EXPORT_SYMBOL(sbi_remote_sfence_vma_asid);
 
+/**
+ * sbi_remote_hfence_gvma() - Execute HFENCE.GVMA instructions on given remote
+ *			   harts for the specified guest physical address range.
+ * @hart_mask: A cpu mask containing all the target harts.
+ * @start: Start of the guest physical address
+ * @size: Total size of the guest physical address range.
+ *
+ * Return: None
+ */
+int sbi_remote_hfence_gvma(const unsigned long *hart_mask,
+			   unsigned long start,
+			   unsigned long size)
+{
+	return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA,
+			    hart_mask, start, size, 0, 0);
+}
+EXPORT_SYMBOL_GPL(sbi_remote_hfence_gvma);
+
+/**
+ * sbi_remote_hfence_gvma_vmid() - Execute HFENCE.GVMA instructions on given
+ * remote harts for a guest physical address range belonging to a specific VMID.
+ *
+ * @hart_mask: A cpu mask containing all the target harts.
+ * @start: Start of the guest physical address
+ * @size: Total size of the guest physical address range.
+ * @vmid: The value of guest ID (VMID).
+ *
+ * Return: 0 if success, Error otherwise.
+ */
+int sbi_remote_hfence_gvma_vmid(const unsigned long *hart_mask,
+				unsigned long start,
+				unsigned long size,
+				unsigned long vmid)
+{
+	return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID,
+			    hart_mask, start, size, vmid, 0);
+}
+EXPORT_SYMBOL(sbi_remote_hfence_gvma_vmid);
+
+/**
+ * sbi_remote_hfence_vvma() - Execute HFENCE.VVMA instructions on given remote
+ *			     harts for the current guest virtual address range.
+ * @hart_mask: A cpu mask containing all the target harts.
+ * @start: Start of the current guest virtual address
+ * @size: Total size of the current guest virtual address range.
+ *
+ * Return: None
+ */
+int sbi_remote_hfence_vvma(const unsigned long *hart_mask,
+			   unsigned long start,
+			   unsigned long size)
+{
+	return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA,
+			    hart_mask, start, size, 0, 0);
+}
+EXPORT_SYMBOL(sbi_remote_hfence_vvma);
+
+/**
+ * sbi_remote_hfence_vvma_asid() - Execute HFENCE.VVMA instructions on given
+ * remote harts for current guest virtual address range belonging to a specific
+ * ASID.
+ *
+ * @hart_mask: A cpu mask containing all the target harts.
+ * @start: Start of the current guest virtual address
+ * @size: Total size of the current guest virtual address range.
+ * @asid: The value of address space identifier (ASID).
+ *
+ * Return: None
+ */
+int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask,
+				unsigned long start,
+				unsigned long size,
+				unsigned long asid)
+{
+	return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID,
+			    hart_mask, start, size, asid, 0);
+}
+EXPORT_SYMBOL(sbi_remote_hfence_vvma_asid);
+
 /**
  * sbi_probe_extension() - Check if an SBI extension ID is supported or not.
  * @extid: The extension ID to be probed.
@@ -332,11 +559,29 @@ int __init sbi_init(void)
 	if (!sbi_spec_is_0_1()) {
 		pr_info("SBI implementation ID=0x%lx Version=0x%lx\n",
 			sbi_get_firmware_id(), sbi_get_firmware_version());
+		if (sbi_probe_extension(SBI_EXT_TIME) > 0) {
+			__sbi_set_timer = __sbi_set_timer_v02;
+			pr_info("SBI v0.2 TIME extension detected\n");
+		} else {
+			__sbi_set_timer = __sbi_set_timer_v01;
+		}
+		if (sbi_probe_extension(SBI_EXT_IPI) > 0) {
+			__sbi_send_ipi	= __sbi_send_ipi_v02;
+			pr_info("SBI v0.2 IPI extension detected\n");
+		} else {
+			__sbi_send_ipi	= __sbi_send_ipi_v01;
+		}
+		if (sbi_probe_extension(SBI_EXT_RFENCE) > 0) {
+			__sbi_rfence	= __sbi_rfence_v02;
+			pr_info("SBI v0.2 RFENCE extension detected\n");
+		} else {
+			__sbi_rfence	= __sbi_rfence_v01;
+		}
+	} else {
+		__sbi_set_timer = __sbi_set_timer_v01;
+		__sbi_send_ipi	= __sbi_send_ipi_v01;
+		__sbi_rfence	= __sbi_rfence_v01;
 	}
 
-	__sbi_set_timer = __sbi_set_timer_v01;
-	__sbi_send_ipi	= __sbi_send_ipi_v01;
-	__sbi_rfence	= __sbi_rfence_v01;
-
 	return 0;
 }
-- 
2.25.1

[PATCH v11 06/11] RISC-V: Move relocate and few other functions out of __init

[Atish Patra]

The secondary hart booting and relocation code are under .init section.
As a result, it will be freed once kernel booting is done. However,
ordered booting protocol and CPU hotplug always requires these functions
to be present to bringup harts after initial kernel boot.

Move the required functions to a different section and make sure that
they are in memory within first 2MB offset as trampoline page directory
only maps first 2MB.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/kernel/head.S        | 153 +++++++++++++++++---------------
 arch/riscv/kernel/vmlinux.lds.S |   5 +-
 2 files changed, 86 insertions(+), 72 deletions(-)

diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 85f2073e7fe4..173507395a6b 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -14,7 +14,7 @@
 #include <asm/hwcap.h>
 #include <asm/image.h>
 
-__INIT
+__HEAD
 ENTRY(_start)
 	/*
 	 * Image header expected by Linux boot-loaders. The image header data
@@ -45,8 +45,85 @@ ENTRY(_start)
 	.ascii RISCV_IMAGE_MAGIC2
 	.word 0
 
-.global _start_kernel
-_start_kernel:
+.align 2
+#ifdef CONFIG_MMU
+relocate:
+	/* Relocate return address */
+	li a1, PAGE_OFFSET
+	la a2, _start
+	sub a1, a1, a2
+	add ra, ra, a1
+
+	/* Point stvec to virtual address of intruction after satp write */
+	la a2, 1f
+	add a2, a2, a1
+	csrw CSR_TVEC, a2
+
+	/* Compute satp for kernel page tables, but don't load it yet */
+	srl a2, a0, PAGE_SHIFT
+	li a1, SATP_MODE
+	or a2, a2, a1
+
+	/*
+	 * Load trampoline page directory, which will cause us to trap to
+	 * stvec if VA != PA, or simply fall through if VA == PA.  We need a
+	 * full fence here because setup_vm() just wrote these PTEs and we need
+	 * to ensure the new translations are in use.
+	 */
+	la a0, trampoline_pg_dir
+	srl a0, a0, PAGE_SHIFT
+	or a0, a0, a1
+	sfence.vma
+	csrw CSR_SATP, a0
+.align 2
+1:
+	/* Set trap vector to spin forever to help debug */
+	la a0, .Lsecondary_park
+	csrw CSR_TVEC, a0
+
+	/* Reload the global pointer */
+.option push
+.option norelax
+	la gp, __global_pointer$
+.option pop
+
+	/*
+	 * Switch to kernel page tables.  A full fence is necessary in order to
+	 * avoid using the trampoline translations, which are only correct for
+	 * the first superpage.  Fetching the fence is guarnteed to work
+	 * because that first superpage is translated the same way.
+	 */
+	csrw CSR_SATP, a2
+	sfence.vma
+
+	ret
+#endif /* CONFIG_MMU */
+#ifdef CONFIG_SMP
+	/* Set trap vector to spin forever to help debug */
+	la a3, .Lsecondary_park
+	csrw CSR_TVEC, a3
+
+	slli a3, a0, LGREG
+	.global secondary_start_common
+secondary_start_common:
+
+#ifdef CONFIG_MMU
+	/* Enable virtual memory and relocate to virtual address */
+	la a0, swapper_pg_dir
+	call relocate
+#endif
+	tail smp_callin
+#endif /* CONFIG_SMP */
+
+.Lsecondary_park:
+	/* We lack SMP support or have too many harts, so park this hart */
+	wfi
+	j .Lsecondary_park
+
+END(_start)
+
+	__INIT
+ENTRY(_start_kernel)
 	/* Mask all interrupts */
 	csrw CSR_IE, zero
 	csrw CSR_IP, zero
@@ -134,59 +211,6 @@ clear_bss_done:
 	call parse_dtb
 	tail start_kernel
 
-#ifdef CONFIG_MMU
-relocate:
-	/* Relocate return address */
-	li a1, PAGE_OFFSET
-	la a2, _start
-	sub a1, a1, a2
-	add ra, ra, a1
-
-	/* Point stvec to virtual address of intruction after satp write */
-	la a2, 1f
-	add a2, a2, a1
-	csrw CSR_TVEC, a2
-
-	/* Compute satp for kernel page tables, but don't load it yet */
-	srl a2, a0, PAGE_SHIFT
-	li a1, SATP_MODE
-	or a2, a2, a1
-
-	/*
-	 * Load trampoline page directory, which will cause us to trap to
-	 * stvec if VA != PA, or simply fall through if VA == PA.  We need a
-	 * full fence here because setup_vm() just wrote these PTEs and we need
-	 * to ensure the new translations are in use.
-	 */
-	la a0, trampoline_pg_dir
-	srl a0, a0, PAGE_SHIFT
-	or a0, a0, a1
-	sfence.vma
-	csrw CSR_SATP, a0
-.align 2
-1:
-	/* Set trap vector to spin forever to help debug */
-	la a0, .Lsecondary_park
-	csrw CSR_TVEC, a0
-
-	/* Reload the global pointer */
-.option push
-.option norelax
-	la gp, __global_pointer$
-.option pop
-
-	/*
-	 * Switch to kernel page tables.  A full fence is necessary in order to
-	 * avoid using the trampoline translations, which are only correct for
-	 * the first superpage.  Fetching the fence is guarnteed to work
-	 * because that first superpage is translated the same way.
-	 */
-	csrw CSR_SATP, a2
-	sfence.vma
-
-	ret
-#endif /* CONFIG_MMU */
-
 .Lsecondary_start:
 #ifdef CONFIG_SMP
 	/* Set trap vector to spin forever to help debug */
@@ -211,16 +235,10 @@ relocate:
 	beqz tp, .Lwait_for_cpu_up
 	fence
 
-#ifdef CONFIG_MMU
-	/* Enable virtual memory and relocate to virtual address */
-	la a0, swapper_pg_dir
-	call relocate
+	tail secondary_start_common
 #endif
 
-	tail smp_callin
-#endif
-
-END(_start)
+END(_start_kernel)
 
 #ifdef CONFIG_RISCV_M_MODE
 ENTRY(reset_regs)
@@ -301,13 +319,6 @@ ENTRY(reset_regs)
 END(reset_regs)
 #endif /* CONFIG_RISCV_M_MODE */
 
-.section ".text", "ax",@progbits
-.align 2
-.Lsecondary_park:
-	/* We lack SMP support or have too many harts, so park this hart */
-	wfi
-	j .Lsecondary_park
-
 __PAGE_ALIGNED_BSS
 	/* Empty zero page */
 	.balign PAGE_SIZE
diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
index 1e0193ded420..b32640300d07 100644
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -10,6 +10,7 @@
 #include <asm/cache.h>
 #include <asm/thread_info.h>
 
+#include <linux/sizes.h>
 OUTPUT_ARCH(riscv)
 ENTRY(_start)
 
@@ -20,8 +21,10 @@ SECTIONS
 	/* Beginning of code and text segment */
 	. = LOAD_OFFSET;
 	_start = .;
-	__init_begin = .;
 	HEAD_TEXT_SECTION
+	. = ALIGN(PAGE_SIZE);
+
+	__init_begin = .;
 	INIT_TEXT_SECTION(PAGE_SIZE)
 	INIT_DATA_SECTION(16)
 	/* we have to discard exit text and such at runtime, not link time */
-- 
2.25.1

[PATCH v11 07/11] RISC-V: Add cpu_ops and modify default booting method

[Atish Patra]

Currently, all non-booting harts start booting after the booting hart
updates the per-hart stack pointer. This is done in a way that, it's
difficult to implement any other booting method without breaking the
backward compatibility.

Define a cpu_ops method that allows to introduce other booting methods
in future. Modify the current booting method to be compatible with
cpu_ops.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/include/asm/cpu_ops.h     | 34 +++++++++++++++++++
 arch/riscv/kernel/Makefile           |  2 ++
 arch/riscv/kernel/cpu_ops.c          | 38 +++++++++++++++++++++
 arch/riscv/kernel/cpu_ops_spinwait.c | 43 +++++++++++++++++++++++
 arch/riscv/kernel/smpboot.c          | 51 ++++++++++++++++------------
 5 files changed, 147 insertions(+), 21 deletions(-)
 create mode 100644 arch/riscv/include/asm/cpu_ops.h
 create mode 100644 arch/riscv/kernel/cpu_ops.c
 create mode 100644 arch/riscv/kernel/cpu_ops_spinwait.c

diff --git a/arch/riscv/include/asm/cpu_ops.h b/arch/riscv/include/asm/cpu_ops.h
new file mode 100644
index 000000000000..5ce81a28e1d9
--- /dev/null
+++ b/arch/riscv/include/asm/cpu_ops.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ * Based on arch/arm64/include/asm/cpu_ops.h
+ */
+#ifndef __ASM_CPU_OPS_H
+#define __ASM_CPU_OPS_H
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/threads.h>
+
+/**
+ * struct cpu_operations - Callback operations for hotplugging CPUs.
+ *
+ * @name:		Name of the boot protocol.
+ * @cpu_prepare:	Early one-time preparation step for a cpu. If there
+ *			is a mechanism for doing so, tests whether it is
+ *			possible to boot the given HART.
+ * @cpu_start:		Boots a cpu into the kernel.
+ */
+struct cpu_operations {
+	const char	*name;
+	int		(*cpu_prepare)(unsigned int cpu);
+	int		(*cpu_start)(unsigned int cpu,
+				     struct task_struct *tidle);
+};
+
+extern const struct cpu_operations *cpu_ops[NR_CPUS];
+void __init cpu_set_ops(int cpu);
+void cpu_update_secondary_bootdata(unsigned int cpuid,
+				   struct task_struct *tidle);
+
+#endif /* ifndef __ASM_CPU_OPS_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index f40205cb9a22..f81a6ff88005 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -32,6 +32,8 @@ obj-$(CONFIG_RISCV_M_MODE)	+= clint.o
 obj-$(CONFIG_FPU)		+= fpu.o
 obj-$(CONFIG_SMP)		+= smpboot.o
 obj-$(CONFIG_SMP)		+= smp.o
+obj-$(CONFIG_SMP)		+= cpu_ops.o
+obj-$(CONFIG_SMP)		+= cpu_ops_spinwait.o
 obj-$(CONFIG_MODULES)		+= module.o
 obj-$(CONFIG_MODULE_SECTIONS)	+= module-sections.o
 
diff --git a/arch/riscv/kernel/cpu_ops.c b/arch/riscv/kernel/cpu_ops.c
new file mode 100644
index 000000000000..62705908eee5
--- /dev/null
+++ b/arch/riscv/kernel/cpu_ops.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/of.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <asm/cpu_ops.h>
+#include <asm/sbi.h>
+#include <asm/smp.h>
+
+const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
+
+void *__cpu_up_stack_pointer[NR_CPUS];
+void *__cpu_up_task_pointer[NR_CPUS];
+
+extern const struct cpu_operations cpu_ops_spinwait;
+
+void cpu_update_secondary_bootdata(unsigned int cpuid,
+				   struct task_struct *tidle)
+{
+	int hartid = cpuid_to_hartid_map(cpuid);
+
+	/* Make sure tidle is updated */
+	smp_mb();
+	WRITE_ONCE(__cpu_up_stack_pointer[hartid],
+		   task_stack_page(tidle) + THREAD_SIZE);
+	WRITE_ONCE(__cpu_up_task_pointer[hartid], tidle);
+}
+
+void __init cpu_set_ops(int cpuid)
+{
+	cpu_ops[cpuid] = &cpu_ops_spinwait;
+}
diff --git a/arch/riscv/kernel/cpu_ops_spinwait.c b/arch/riscv/kernel/cpu_ops_spinwait.c
new file mode 100644
index 000000000000..b2c957bb68c1
--- /dev/null
+++ b/arch/riscv/kernel/cpu_ops_spinwait.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/errno.h>
+#include <linux/of.h>
+#include <linux/string.h>
+#include <asm/cpu_ops.h>
+#include <asm/sbi.h>
+#include <asm/smp.h>
+
+const struct cpu_operations cpu_ops_spinwait;
+
+static int spinwait_cpu_prepare(unsigned int cpuid)
+{
+	if (!cpu_ops_spinwait.cpu_start) {
+		pr_err("cpu start method not defined for CPU [%d]\n", cpuid);
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static int spinwait_cpu_start(unsigned int cpuid, struct task_struct *tidle)
+{
+	/*
+	 * In this protocol, all cpus boot on their own accord.  _start
+	 * selects the first cpu to boot the kernel and causes the remainder
+	 * of the cpus to spin in a loop waiting for their stack pointer to be
+	 * setup by that main cpu.  Writing to bootdata
+	 * (i.e __cpu_up_stack_pointer) signals to the spinning cpus that they
+	 * can continue the boot process.
+	 */
+	cpu_update_secondary_bootdata(cpuid, tidle);
+
+	return 0;
+}
+
+const struct cpu_operations cpu_ops_spinwait = {
+	.name		= "spinwait",
+	.cpu_prepare	= spinwait_cpu_prepare,
+	.cpu_start	= spinwait_cpu_start,
+};
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 8bc01f0ca73b..e89396a2a1af 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -25,6 +25,7 @@
 #include <linux/sched/task_stack.h>
 #include <linux/sched/mm.h>
 #include <asm/clint.h>
+#include <asm/cpu_ops.h>
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
@@ -34,8 +35,6 @@
 
 #include "head.h"
 
-void *__cpu_up_stack_pointer[NR_CPUS];
-void *__cpu_up_task_pointer[NR_CPUS];
 static DECLARE_COMPLETION(cpu_running);
 
 void __init smp_prepare_boot_cpu(void)
@@ -46,6 +45,7 @@ void __init smp_prepare_boot_cpu(void)
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
 	int cpuid;
+	int ret;
 
 	/* This covers non-smp usecase mandated by "nosmp" option */
 	if (max_cpus == 0)
@@ -54,6 +54,11 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	for_each_possible_cpu(cpuid) {
 		if (cpuid == smp_processor_id())
 			continue;
+		if (cpu_ops[cpuid]->cpu_prepare) {
+			ret = cpu_ops[cpuid]->cpu_prepare(cpuid);
+			if (ret)
+				continue;
+		}
 		set_cpu_present(cpuid, true);
 	}
 }
@@ -65,6 +70,8 @@ void __init setup_smp(void)
 	bool found_boot_cpu = false;
 	int cpuid = 1;
 
+	cpu_set_ops(0);
+
 	for_each_of_cpu_node(dn) {
 		hart = riscv_of_processor_hartid(dn);
 		if (hart < 0)
@@ -92,36 +99,38 @@ void __init setup_smp(void)
 			cpuid, nr_cpu_ids);
 
 	for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
-		if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID)
+		if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) {
+			cpu_set_ops(cpuid);
 			set_cpu_possible(cpuid, true);
+		}
 	}
 }
 
+int start_secondary_cpu(int cpu, struct task_struct *tidle)
+{
+	if (cpu_ops[cpu]->cpu_start)
+		return cpu_ops[cpu]->cpu_start(cpu, tidle);
+
+	return -EOPNOTSUPP;
+}
+
 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	int ret = 0;
-	int hartid = cpuid_to_hartid_map(cpu);
 	tidle->thread_info.cpu = cpu;
 
-	/*
-	 * On RISC-V systems, all harts boot on their own accord.  Our _start
-	 * selects the first hart to boot the kernel and causes the remainder
-	 * of the harts to spin in a loop waiting for their stack pointer to be
-	 * setup by that main hart.  Writing __cpu_up_stack_pointer signals to
-	 * the spinning harts that they can continue the boot process.
-	 */
-	smp_mb();
-	WRITE_ONCE(__cpu_up_stack_pointer[hartid],
-		  task_stack_page(tidle) + THREAD_SIZE);
-	WRITE_ONCE(__cpu_up_task_pointer[hartid], tidle);
-
-	lockdep_assert_held(&cpu_running);
-	wait_for_completion_timeout(&cpu_running,
+	ret = start_secondary_cpu(cpu, tidle);
+	if (!ret) {
+		lockdep_assert_held(&cpu_running);
+		wait_for_completion_timeout(&cpu_running,
 					    msecs_to_jiffies(1000));
 
-	if (!cpu_online(cpu)) {
-		pr_crit("CPU%u: failed to come online\n", cpu);
-		ret = -EIO;
+		if (!cpu_online(cpu)) {
+			pr_crit("CPU%u: failed to come online\n", cpu);
+			ret = -EIO;
+		}
+	} else {
+		pr_crit("CPU%u: failed to start\n", cpu);
 	}
 
 	return ret;
-- 
2.25.1

[PATCH v11 08/11] RISC-V: Export SBI error to linux error mapping function

[Atish Patra]

All SBI related extensions will not be implemented in sbi.c to avoid
bloating. Thus, sbi_err_map_linux_errno() will be used in other files
implementing that specific extension.

Export the function so that it can be used later.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
---
 arch/riscv/include/asm/sbi.h | 2 ++
 arch/riscv/kernel/sbi.c      | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 29ce2c494386..2bbfd6bada93 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -130,6 +130,8 @@ static inline unsigned long sbi_minor_version(void)
 {
 	return sbi_spec_version & SBI_SPEC_VERSION_MINOR_MASK;
 }
+
+int sbi_err_map_linux_errno(int err);
 #else /* CONFIG_RISCV_SBI */
 /* stubs for code that is only reachable under IS_ENABLED(CONFIG_RISCV_SBI): */
 void sbi_set_timer(uint64_t stime_value);
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 1cc0052e1b63..7c24da59bccf 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -46,7 +46,7 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
 }
 EXPORT_SYMBOL(sbi_ecall);
 
-static int sbi_err_map_linux_errno(int err)
+int sbi_err_map_linux_errno(int err)
 {
 	switch (err) {
 	case SBI_SUCCESS:
@@ -63,6 +63,7 @@ static int sbi_err_map_linux_errno(int err)
 		return -ENOTSUPP;
 	};
 }
+EXPORT_SYMBOL(sbi_err_map_linux_errno);
 
 #ifdef CONFIG_RISCV_SBI_V01
 /**
-- 
2.25.1

[PATCH v11 09/11] RISC-V: Add SBI HSM extension definitions

[Atish Patra]

SBI specification defines HSM extension that allows to start/stop a hart
by a supervisor anytime. The specification is available at

https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc

Add those definitions here.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
---
 arch/riscv/include/asm/sbi.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 2bbfd6bada93..653edb25d495 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -26,6 +26,7 @@ enum sbi_ext_id {
 	SBI_EXT_TIME = 0x54494D45,
 	SBI_EXT_IPI = 0x735049,
 	SBI_EXT_RFENCE = 0x52464E43,
+	SBI_EXT_HSM = 0x48534D,
 };
 
 enum sbi_ext_base_fid {
@@ -56,6 +57,19 @@ enum sbi_ext_rfence_fid {
 	SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID,
 };
 
+enum sbi_ext_hsm_fid {
+	SBI_EXT_HSM_HART_START = 0,
+	SBI_EXT_HSM_HART_STOP,
+	SBI_EXT_HSM_HART_STATUS,
+};
+
+enum sbi_hsm_hart_status {
+	SBI_HSM_HART_STATUS_STARTED = 0,
+	SBI_HSM_HART_STATUS_STOPPED,
+	SBI_HSM_HART_STATUS_START_PENDING,
+	SBI_HSM_HART_STATUS_STOP_PENDING,
+};
+
 #define SBI_SPEC_VERSION_DEFAULT	0x1
 #define SBI_SPEC_VERSION_MAJOR_SHIFT	24
 #define SBI_SPEC_VERSION_MAJOR_MASK	0x7f
-- 
2.25.1

[PATCH v11 10/11] RISC-V: Add supported for ordered booting method using HSM

[Atish Patra]

Currently, all harts have to jump Linux in RISC-V. This complicates the
multi-stage boot process as every transient stage also has to ensure all
harts enter to that stage and jump to Linux afterwards. It also obstructs
a clean Kexec implementation.

SBI HSM extension provides alternate solutions where only a single hart
need to boot and enter Linux. The booting hart can bring up secondary
harts one by one afterwards.

Add SBI HSM based cpu_ops that implements an ordered booting method in
RISC-V. This change is also backward compatible with older firmware not
implementing HSM extension. If a latest kernel is used with older
firmware, it will continue to use the default spinning booting method.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/kernel/Makefile      |  3 ++
 arch/riscv/kernel/cpu_ops.c     | 10 +++-
 arch/riscv/kernel/cpu_ops_sbi.c | 81 +++++++++++++++++++++++++++++++++
 arch/riscv/kernel/head.S        | 26 +++++++++++
 arch/riscv/kernel/smpboot.c     |  2 +-
 arch/riscv/kernel/traps.c       |  2 +-
 6 files changed, 121 insertions(+), 3 deletions(-)
 create mode 100644 arch/riscv/kernel/cpu_ops_sbi.c

diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index f81a6ff88005..a0be34b96846 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -44,5 +44,8 @@ obj-$(CONFIG_PERF_EVENTS)	+= perf_event.o
 obj-$(CONFIG_PERF_EVENTS)	+= perf_callchain.o
 obj-$(CONFIG_HAVE_PERF_REGS)	+= perf_regs.o
 obj-$(CONFIG_RISCV_SBI)		+= sbi.o
+ifeq ($(CONFIG_RISCV_SBI), y)
+obj-$(CONFIG_SMP) += cpu_ops_sbi.o
+endif
 
 clean:
diff --git a/arch/riscv/kernel/cpu_ops.c b/arch/riscv/kernel/cpu_ops.c
index 62705908eee5..c4c33bf02369 100644
--- a/arch/riscv/kernel/cpu_ops.c
+++ b/arch/riscv/kernel/cpu_ops.c
@@ -18,6 +18,7 @@ const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
 void *__cpu_up_stack_pointer[NR_CPUS];
 void *__cpu_up_task_pointer[NR_CPUS];
 
+extern const struct cpu_operations cpu_ops_sbi;
 extern const struct cpu_operations cpu_ops_spinwait;
 
 void cpu_update_secondary_bootdata(unsigned int cpuid,
@@ -34,5 +35,12 @@ void cpu_update_secondary_bootdata(unsigned int cpuid,
 
 void __init cpu_set_ops(int cpuid)
 {
-	cpu_ops[cpuid] = &cpu_ops_spinwait;
+#if IS_ENABLED(CONFIG_RISCV_SBI)
+	if (sbi_probe_extension(SBI_EXT_HSM) > 0) {
+		if (!cpuid)
+			pr_info("SBI v0.2 HSM extension detected\n");
+		cpu_ops[cpuid] = &cpu_ops_sbi;
+	} else
+#endif
+		cpu_ops[cpuid] = &cpu_ops_spinwait;
 }
diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
new file mode 100644
index 000000000000..66f3cded91f5
--- /dev/null
+++ b/arch/riscv/kernel/cpu_ops_sbi.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HSM extension and cpu_ops implementation.
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <asm/cpu_ops.h>
+#include <asm/sbi.h>
+#include <asm/smp.h>
+
+extern char secondary_start_sbi[];
+const struct cpu_operations cpu_ops_sbi;
+
+static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr,
+			      unsigned long priv)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
+			hartid, saddr, priv, 0, 0, 0);
+	if (ret.error)
+		return sbi_err_map_linux_errno(ret.error);
+	else
+		return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int sbi_hsm_hart_stop(void)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STOP, 0, 0, 0, 0, 0, 0);
+
+	if (ret.error)
+		return sbi_err_map_linux_errno(ret.error);
+	else
+		return 0;
+}
+
+static int sbi_hsm_hart_get_status(unsigned long hartid)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STATUS,
+			hartid, 0, 0, 0, 0, 0);
+	if (ret.error)
+		return sbi_err_map_linux_errno(ret.error);
+	else
+		return ret.value;
+}
+#endif
+
+static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle)
+{
+	int rc;
+	unsigned long boot_addr = __pa_symbol(secondary_start_sbi);
+	int hartid = cpuid_to_hartid_map(cpuid);
+
+	cpu_update_secondary_bootdata(cpuid, tidle);
+	rc = sbi_hsm_hart_start(hartid, boot_addr, 0);
+
+	return rc;
+}
+
+static int sbi_cpu_prepare(unsigned int cpuid)
+{
+	if (!cpu_ops_sbi.cpu_start) {
+		pr_err("cpu start method not defined for CPU [%d]\n", cpuid);
+		return -ENODEV;
+	}
+	return 0;
+}
+
+const struct cpu_operations cpu_ops_sbi = {
+	.name		= "sbi",
+	.cpu_prepare	= sbi_cpu_prepare,
+	.cpu_start	= sbi_cpu_start,
+};
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 173507395a6b..e5115d5e0b3a 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -99,11 +99,37 @@ relocate:
 	ret
 #endif /* CONFIG_MMU */
 #ifdef CONFIG_SMP
+	.global secondary_start_sbi
+secondary_start_sbi:
+	/* Mask all interrupts */
+	csrw CSR_IE, zero
+	csrw CSR_IP, zero
+
+	/* Load the global pointer */
+	.option push
+	.option norelax
+		la gp, __global_pointer$
+	.option pop
+
+	/*
+	 * Disable FPU to detect illegal usage of
+	 * floating point in kernel space
+	 */
+	li t0, SR_FS
+	csrc CSR_STATUS, t0
+
 	/* Set trap vector to spin forever to help debug */
 	la a3, .Lsecondary_park
 	csrw CSR_TVEC, a3
 
 	slli a3, a0, LGREG
+	la a4, __cpu_up_stack_pointer
+	la a5, __cpu_up_task_pointer
+	add a4, a3, a4
+	add a5, a3, a5
+	REG_L sp, (a4)
+	REG_L tp, (a5)
+
 	.global secondary_start_common
 secondary_start_common:
 
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index e89396a2a1af..4e9922790f6e 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -143,7 +143,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 /*
  * C entry point for a secondary processor.
  */
-asmlinkage __visible void __init smp_callin(void)
+asmlinkage __visible void smp_callin(void)
 {
 	struct mm_struct *mm = &init_mm;
 
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index ffb3d94bf0cc..8e13ad45ccaa 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -147,7 +147,7 @@ int is_valid_bugaddr(unsigned long pc)
 }
 #endif /* CONFIG_GENERIC_BUG */
 
-void __init trap_init(void)
+void trap_init(void)
 {
 	/*
 	 * Set sup0 scratch register to 0, indicating to exception vector
-- 
2.25.1

[PATCH v11 11/11] RISC-V: Support cpu hotplug

[Atish Patra]

This patch enable support for cpu hotplug in RISC-V. It uses SBI HSM
extension to online/offline any hart. As a result, the harts are
returned to firmware once they are offline. If the harts are brought
online afterwards, they re-enter Linux kernel as if a secondary hart
booted for the first time. All booting requirements are honored during
this process.

Tested both on QEMU and HighFive Unleashed board with. Test result follows.

---------------------------------------------------
Offline cpu 2
---------------------------------------------------
$ echo 0 > /sys/devices/system/cpu/cpu2/online
[   32.828684] CPU2: off
$ cat /proc/cpuinfo
processor       : 0
hart            : 0
isa             : rv64imafdcsu
mmu             : sv48

processor       : 1
hart            : 1
isa             : rv64imafdcsu
mmu             : sv48

processor       : 3
hart            : 3
isa             : rv64imafdcsu
mmu             : sv48

processor       : 4
hart            : 4
isa             : rv64imafdcsu
mmu             : sv48

processor       : 5
hart            : 5
isa             : rv64imafdcsu
mmu             : sv48

processor       : 6
hart            : 6
isa             : rv64imafdcsu
mmu             : sv48

processor       : 7
hart            : 7
isa             : rv64imafdcsu
mmu             : sv48

---------------------------------------------------
online cpu 2
---------------------------------------------------
$ echo 1 > /sys/devices/system/cpu/cpu2/online
$ cat /proc/cpuinfo
processor       : 0
hart            : 0
isa             : rv64imafdcsu
mmu             : sv48

processor       : 1
hart            : 1
isa             : rv64imafdcsu
mmu             : sv48

processor       : 2
hart            : 2
isa             : rv64imafdcsu
mmu             : sv48

processor       : 3
hart            : 3
isa             : rv64imafdcsu
mmu             : sv48

processor       : 4
hart            : 4
isa             : rv64imafdcsu
mmu             : sv48

processor       : 5
hart            : 5
isa             : rv64imafdcsu
mmu             : sv48

processor       : 6
hart            : 6
isa             : rv64imafdcsu
mmu             : sv48

processor       : 7
hart            : 7
isa             : rv64imafdcsu
mmu             : sv48

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/Kconfig               | 12 ++++-
 arch/riscv/include/asm/cpu_ops.h | 12 +++++
 arch/riscv/include/asm/smp.h     | 17 +++++++
 arch/riscv/kernel/Makefile       |  1 +
 arch/riscv/kernel/cpu-hotplug.c  | 87 ++++++++++++++++++++++++++++++++
 arch/riscv/kernel/cpu_ops_sbi.c  | 34 +++++++++++++
 arch/riscv/kernel/setup.c        | 19 ++++++-
 7 files changed, 180 insertions(+), 2 deletions(-)
 create mode 100644 arch/riscv/kernel/cpu-hotplug.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 20c6191399ea..b3daadd116ec 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -20,7 +20,6 @@ config RISCV
 	select CLONE_BACKWARDS
 	select COMMON_CLK
 	select GENERIC_CLOCKEVENTS
-	select GENERIC_CPU_DEVICES
 	select GENERIC_IRQ_SHOW
 	select GENERIC_PCI_IOMAP
 	select GENERIC_SCHED_CLOCK
@@ -248,6 +247,17 @@ config NR_CPUS
 	depends on SMP
 	default "8"
 
+config HOTPLUG_CPU
+	bool "Support for hot-pluggable CPUs"
+	depends on SMP
+	select GENERIC_IRQ_MIGRATION
+	help
+
+	  Say Y here to experiment with turning CPUs off and on.  CPUs
+	  can be controlled through /sys/devices/system/cpu.
+
+	  Say N if you want to disable CPU hotplug.
+
 choice
 	prompt "CPU Tuning"
 	default TUNE_GENERIC
diff --git a/arch/riscv/include/asm/cpu_ops.h b/arch/riscv/include/asm/cpu_ops.h
index 5ce81a28e1d9..a8ec3c5c1bd2 100644
--- a/arch/riscv/include/asm/cpu_ops.h
+++ b/arch/riscv/include/asm/cpu_ops.h
@@ -18,12 +18,24 @@
  *			is a mechanism for doing so, tests whether it is
  *			possible to boot the given HART.
  * @cpu_start:		Boots a cpu into the kernel.
+ * @cpu_disable:	Prepares a cpu to die. May fail for some
+ *			mechanism-specific reason, which will cause the hot
+ *			unplug to be aborted. Called from the cpu to be killed.
+ * @cpu_stop:		Makes a cpu leave the kernel. Must not fail. Called from
+ *			the cpu being stopped.
+ * @cpu_is_stopped:	Ensures a cpu has left the kernel. Called from another
+ *			cpu.
  */
 struct cpu_operations {
 	const char	*name;
 	int		(*cpu_prepare)(unsigned int cpu);
 	int		(*cpu_start)(unsigned int cpu,
 				     struct task_struct *tidle);
+#ifdef CONFIG_HOTPLUG_CPU
+	int		(*cpu_disable)(unsigned int cpu);
+	void		(*cpu_stop)(void);
+	int		(*cpu_is_stopped)(unsigned int cpu);
+#endif
 };
 
 extern const struct cpu_operations *cpu_ops[NR_CPUS];
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 023f74fb8b3b..f4c7cfda6b7f 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -43,6 +43,13 @@ void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out);
  */
 #define raw_smp_processor_id() (current_thread_info()->cpu)
 
+#if defined CONFIG_HOTPLUG_CPU
+int __cpu_disable(void);
+void __cpu_die(unsigned int cpu);
+void cpu_stop(void);
+#else
+#endif /* CONFIG_HOTPLUG_CPU */
+
 #else
 
 static inline void show_ipi_stats(struct seq_file *p, int prec)
@@ -69,4 +76,14 @@ static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
 }
 
 #endif /* CONFIG_SMP */
+
+#if defined(CONFIG_HOTPLUG_CPU) && (CONFIG_SMP)
+bool cpu_has_hotplug(unsigned int cpu);
+#else
+static inline bool cpu_has_hotplug(unsigned int cpu)
+{
+	return false;
+}
+#endif
+
 #endif /* _ASM_RISCV_SMP_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index a0be34b96846..9601ac907f70 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -47,5 +47,6 @@ obj-$(CONFIG_RISCV_SBI)		+= sbi.o
 ifeq ($(CONFIG_RISCV_SBI), y)
 obj-$(CONFIG_SMP) += cpu_ops_sbi.o
 endif
+obj-$(CONFIG_HOTPLUG_CPU)	+= cpu-hotplug.o
 
 clean:
diff --git a/arch/riscv/kernel/cpu-hotplug.c b/arch/riscv/kernel/cpu-hotplug.c
new file mode 100644
index 000000000000..df84e0c13db1
--- /dev/null
+++ b/arch/riscv/kernel/cpu-hotplug.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/err.h>
+#include <linux/irq.h>
+#include <linux/cpu.h>
+#include <linux/sched/hotplug.h>
+#include <asm/irq.h>
+#include <asm/cpu_ops.h>
+#include <asm/sbi.h>
+
+void cpu_stop(void);
+void arch_cpu_idle_dead(void)
+{
+	cpu_stop();
+}
+
+bool cpu_has_hotplug(unsigned int cpu)
+{
+	if (cpu_ops[cpu]->cpu_stop)
+		return true;
+
+	return false;
+}
+
+/*
+ * __cpu_disable runs on the processor to be shutdown.
+ */
+int __cpu_disable(void)
+{
+	int ret = 0;
+	unsigned int cpu = smp_processor_id();
+
+	if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop)
+		return -EOPNOTSUPP;
+
+	if (cpu_ops[cpu]->cpu_disable)
+		ret = cpu_ops[cpu]->cpu_disable(cpu);
+
+	if (ret)
+		return ret;
+
+	remove_cpu_topology(cpu);
+	set_cpu_online(cpu, false);
+	irq_migrate_all_off_this_cpu();
+
+	return ret;
+}
+
+/*
+ * Called on the thread which is asking for a CPU to be shutdown.
+ */
+void __cpu_die(unsigned int cpu)
+{
+	int ret = 0;
+
+	if (!cpu_wait_death(cpu, 5)) {
+		pr_err("CPU %u: didn't die\n", cpu);
+		return;
+	}
+	pr_notice("CPU%u: off\n", cpu);
+
+	/* Verify from the firmware if the cpu is really stopped*/
+	if (cpu_ops[cpu]->cpu_is_stopped)
+		ret = cpu_ops[cpu]->cpu_is_stopped(cpu);
+	if (ret)
+		pr_warn("CPU%d may not have stopped: %d\n", cpu, ret);
+}
+
+/*
+ * Called from the idle thread for the CPU which has been shutdown.
+ */
+void cpu_stop(void)
+{
+	idle_task_exit();
+
+	(void)cpu_report_death();
+
+	cpu_ops[smp_processor_id()]->cpu_stop();
+	/* It should never reach here */
+	BUG();
+}
diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
index 66f3cded91f5..685fae72b7f5 100644
--- a/arch/riscv/kernel/cpu_ops_sbi.c
+++ b/arch/riscv/kernel/cpu_ops_sbi.c
@@ -74,8 +74,42 @@ static int sbi_cpu_prepare(unsigned int cpuid)
 	return 0;
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+static int sbi_cpu_disable(unsigned int cpuid)
+{
+	if (!cpu_ops_sbi.cpu_stop)
+		return -EOPNOTSUPP;
+	return 0;
+}
+
+static void sbi_cpu_stop(void)
+{
+	int ret;
+
+	ret = sbi_hsm_hart_stop();
+	pr_crit("Unable to stop the cpu %u (%d)\n", smp_processor_id(), ret);
+}
+
+static int sbi_cpu_is_stopped(unsigned int cpuid)
+{
+	int rc;
+	int hartid = cpuid_to_hartid_map(cpuid);
+
+	rc = sbi_hsm_hart_get_status(hartid);
+
+	if (rc == SBI_HSM_HART_STATUS_STOPPED)
+		return 0;
+	return rc;
+}
+#endif
+
 const struct cpu_operations cpu_ops_sbi = {
 	.name		= "sbi",
 	.cpu_prepare	= sbi_cpu_prepare,
 	.cpu_start	= sbi_cpu_start,
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_disable	= sbi_cpu_disable,
+	.cpu_stop	= sbi_cpu_stop,
+	.cpu_is_stopped	= sbi_cpu_is_stopped,
+#endif
 };
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 44ac4ddf60ab..1d2f66579b94 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -16,12 +16,13 @@
 #include <linux/of_platform.h>
 #include <linux/sched/task.h>
 #include <linux/swiotlb.h>
+#include <linux/smp.h>
 
 #include <asm/clint.h>
+#include <asm/cpu_ops.h>
 #include <asm/setup.h>
 #include <asm/sections.h>
 #include <asm/pgtable.h>
-#include <asm/smp.h>
 #include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/thread_info.h>
@@ -43,6 +44,7 @@ struct screen_info screen_info = {
 /* The lucky hart to first increment this variable will boot the other cores */
 atomic_t hart_lottery;
 unsigned long boot_cpu_hartid;
+static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
 void __init parse_dtb(void)
 {
@@ -90,3 +92,18 @@ void __init setup_arch(char **cmdline_p)
 
 	riscv_fill_hwcap();
 }
+
+static int __init topology_init(void)
+{
+	int i;
+
+	for_each_possible_cpu(i) {
+		struct cpu *cpu = &per_cpu(cpu_devices, i);
+
+		cpu->hotpluggable = cpu_has_hotplug(i);
+		register_cpu(cpu, i);
+	}
+
+	return 0;
+}
+subsys_initcall(topology_init);
-- 
2.25.1

Re: [PATCH v11 00/11] Add support for SBI v0.2 and CPU hotplug

[Emil Renner Berthing]

Hi Atish,

On Wed, 18 Mar 2020 at 02:12, Atish Patra <atish.patra@wdc.com> wrote:
>
> The Supervisor Binary Interface(SBI) specification[1] now defines a
> base extension that provides extendability to add future extensions
> while maintaining backward compatibility with previous versions.
> The new version is defined as 0.2 and older version is marked as 0.1.
>
> This series adds following features to RISC-V Linux.
> 1. Adds support for SBI v0.2
> 2. A Unified calling convention implementation between 0.1 and 0.2.
> 3. SBI Hart state management extension (HSM)
> 4. Ordered booting of harts
> 4. CPU hotplug

If it's any help I tried this series with both OpenSBI v0.6 and master
(9a74a64ae08),
and in both cases Linux found all four cpus. I can test the hotplug
stuff too if you send
me instructions. In any case you can add my

Tested-by: Emil Renner Berthing <kernel@esmil.dk>

/Emil

Re: [PATCH v11 00/11] Add support for SBI v0.2 and CPU hotplug

[Atish Patra]

On Sun, Mar 22, 2020 at 10:49 AM Emil Renner Berthing
<emil.renner.berthing@gmail.com> wrote:
>
> Hi Atish,
>
> On Wed, 18 Mar 2020 at 02:12, Atish Patra <atish.patra@wdc.com> wrote:
> >
> > The Supervisor Binary Interface(SBI) specification[1] now defines a
> > base extension that provides extendability to add future extensions
> > while maintaining backward compatibility with previous versions.
> > The new version is defined as 0.2 and older version is marked as 0.1.
> >
> > This series adds following features to RISC-V Linux.
> > 1. Adds support for SBI v0.2
> > 2. A Unified calling convention implementation between 0.1 and 0.2.
> > 3. SBI Hart state management extension (HSM)
> > 4. Ordered booting of harts
> > 4. CPU hotplug
>
> If it's any help I tried this series with both OpenSBI v0.6 and master
> (9a74a64ae08),
> and in both cases Linux found all four cpus. I can test the hotplug
> stuff too if you send
> me instructions. In any case you can add my
>
> Tested-by: Emil Renner Berthing <kernel@esmil.dk>
>

Thanks for testing the patches. Here are the steps to online/offline a cpu.

To mark a cpu offline
$echo 0 > /sys/devices/system/cpu/cpuX/online

To mark a cpu online
$echo 1 > /sys/devices/system/cpu/cpuX/online

Here are the official kernel documentation.
https://www.kernel.org/doc/html/latest/core-api/cpu_hotplug.html

> /Emil
>


-- 
Regards,
Atish

Re: [PATCH v11 11/11] RISC-V: Support cpu hotplug

[Palmer Dabbelt]

On Tue, 17 Mar 2020 18:11:44 PDT (-0700), Atish Patra wrote:
> This patch enable support for cpu hotplug in RISC-V. It uses SBI HSM
> extension to online/offline any hart. As a result, the harts are
> returned to firmware once they are offline. If the harts are brought
> online afterwards, they re-enter Linux kernel as if a secondary hart
> booted for the first time. All booting requirements are honored during
> this process.
>
> Tested both on QEMU and HighFive Unleashed board with. Test result follows.

I had to jump through some hoops to apply this one on for-next.  It should be
f1e58583b9c7 ("RISC-V: Support cpu hotplug") now, LMK if something went wrong.

>
> ---------------------------------------------------
> Offline cpu 2
> ---------------------------------------------------
> $ echo 0 > /sys/devices/system/cpu/cpu2/online
> [   32.828684] CPU2: off
> $ cat /proc/cpuinfo
> processor       : 0
> hart            : 0
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 1
> hart            : 1
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 3
> hart            : 3
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 4
> hart            : 4
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 5
> hart            : 5
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 6
> hart            : 6
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 7
> hart            : 7
> isa             : rv64imafdcsu
> mmu             : sv48
>
> ---------------------------------------------------
> online cpu 2
> ---------------------------------------------------
> $ echo 1 > /sys/devices/system/cpu/cpu2/online
> $ cat /proc/cpuinfo
> processor       : 0
> hart            : 0
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 1
> hart            : 1
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 2
> hart            : 2
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 3
> hart            : 3
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 4
> hart            : 4
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 5
> hart            : 5
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 6
> hart            : 6
> isa             : rv64imafdcsu
> mmu             : sv48
>
> processor       : 7
> hart            : 7
> isa             : rv64imafdcsu
> mmu             : sv48
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> ---
>  arch/riscv/Kconfig               | 12 ++++-
>  arch/riscv/include/asm/cpu_ops.h | 12 +++++
>  arch/riscv/include/asm/smp.h     | 17 +++++++
>  arch/riscv/kernel/Makefile       |  1 +
>  arch/riscv/kernel/cpu-hotplug.c  | 87 ++++++++++++++++++++++++++++++++
>  arch/riscv/kernel/cpu_ops_sbi.c  | 34 +++++++++++++
>  arch/riscv/kernel/setup.c        | 19 ++++++-
>  7 files changed, 180 insertions(+), 2 deletions(-)
>  create mode 100644 arch/riscv/kernel/cpu-hotplug.c
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 20c6191399ea..b3daadd116ec 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -20,7 +20,6 @@ config RISCV
>  	select CLONE_BACKWARDS
>  	select COMMON_CLK
>  	select GENERIC_CLOCKEVENTS
> -	select GENERIC_CPU_DEVICES
>  	select GENERIC_IRQ_SHOW
>  	select GENERIC_PCI_IOMAP
>  	select GENERIC_SCHED_CLOCK
> @@ -248,6 +247,17 @@ config NR_CPUS
>  	depends on SMP
>  	default "8"
>
> +config HOTPLUG_CPU
> +	bool "Support for hot-pluggable CPUs"
> +	depends on SMP
> +	select GENERIC_IRQ_MIGRATION
> +	help
> +
> +	  Say Y here to experiment with turning CPUs off and on.  CPUs
> +	  can be controlled through /sys/devices/system/cpu.
> +
> +	  Say N if you want to disable CPU hotplug.
> +
>  choice
>  	prompt "CPU Tuning"
>  	default TUNE_GENERIC
> diff --git a/arch/riscv/include/asm/cpu_ops.h b/arch/riscv/include/asm/cpu_ops.h
> index 5ce81a28e1d9..a8ec3c5c1bd2 100644
> --- a/arch/riscv/include/asm/cpu_ops.h
> +++ b/arch/riscv/include/asm/cpu_ops.h
> @@ -18,12 +18,24 @@
>   *			is a mechanism for doing so, tests whether it is
>   *			possible to boot the given HART.
>   * @cpu_start:		Boots a cpu into the kernel.
> + * @cpu_disable:	Prepares a cpu to die. May fail for some
> + *			mechanism-specific reason, which will cause the hot
> + *			unplug to be aborted. Called from the cpu to be killed.
> + * @cpu_stop:		Makes a cpu leave the kernel. Must not fail. Called from
> + *			the cpu being stopped.
> + * @cpu_is_stopped:	Ensures a cpu has left the kernel. Called from another
> + *			cpu.
>   */
>  struct cpu_operations {
>  	const char	*name;
>  	int		(*cpu_prepare)(unsigned int cpu);
>  	int		(*cpu_start)(unsigned int cpu,
>  				     struct task_struct *tidle);
> +#ifdef CONFIG_HOTPLUG_CPU
> +	int		(*cpu_disable)(unsigned int cpu);
> +	void		(*cpu_stop)(void);
> +	int		(*cpu_is_stopped)(unsigned int cpu);
> +#endif
>  };
>
>  extern const struct cpu_operations *cpu_ops[NR_CPUS];
> diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
> index 023f74fb8b3b..f4c7cfda6b7f 100644
> --- a/arch/riscv/include/asm/smp.h
> +++ b/arch/riscv/include/asm/smp.h
> @@ -43,6 +43,13 @@ void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out);
>   */
>  #define raw_smp_processor_id() (current_thread_info()->cpu)
>
> +#if defined CONFIG_HOTPLUG_CPU
> +int __cpu_disable(void);
> +void __cpu_die(unsigned int cpu);
> +void cpu_stop(void);
> +#else
> +#endif /* CONFIG_HOTPLUG_CPU */
> +
>  #else
>
>  static inline void show_ipi_stats(struct seq_file *p, int prec)
> @@ -69,4 +76,14 @@ static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
>  }
>
>  #endif /* CONFIG_SMP */
> +
> +#if defined(CONFIG_HOTPLUG_CPU) && (CONFIG_SMP)
> +bool cpu_has_hotplug(unsigned int cpu);
> +#else
> +static inline bool cpu_has_hotplug(unsigned int cpu)
> +{
> +	return false;
> +}
> +#endif
> +
>  #endif /* _ASM_RISCV_SMP_H */
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index a0be34b96846..9601ac907f70 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -47,5 +47,6 @@ obj-$(CONFIG_RISCV_SBI)		+= sbi.o
>  ifeq ($(CONFIG_RISCV_SBI), y)
>  obj-$(CONFIG_SMP) += cpu_ops_sbi.o
>  endif
> +obj-$(CONFIG_HOTPLUG_CPU)	+= cpu-hotplug.o
>
>  clean:
> diff --git a/arch/riscv/kernel/cpu-hotplug.c b/arch/riscv/kernel/cpu-hotplug.c
> new file mode 100644
> index 000000000000..df84e0c13db1
> --- /dev/null
> +++ b/arch/riscv/kernel/cpu-hotplug.c
> @@ -0,0 +1,87 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020 Western Digital Corporation or its affiliates.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/mm.h>
> +#include <linux/sched.h>
> +#include <linux/err.h>
> +#include <linux/irq.h>
> +#include <linux/cpu.h>
> +#include <linux/sched/hotplug.h>
> +#include <asm/irq.h>
> +#include <asm/cpu_ops.h>
> +#include <asm/sbi.h>
> +
> +void cpu_stop(void);
> +void arch_cpu_idle_dead(void)
> +{
> +	cpu_stop();
> +}
> +
> +bool cpu_has_hotplug(unsigned int cpu)
> +{
> +	if (cpu_ops[cpu]->cpu_stop)
> +		return true;
> +
> +	return false;
> +}
> +
> +/*
> + * __cpu_disable runs on the processor to be shutdown.
> + */
> +int __cpu_disable(void)
> +{
> +	int ret = 0;
> +	unsigned int cpu = smp_processor_id();
> +
> +	if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop)
> +		return -EOPNOTSUPP;
> +
> +	if (cpu_ops[cpu]->cpu_disable)
> +		ret = cpu_ops[cpu]->cpu_disable(cpu);
> +
> +	if (ret)
> +		return ret;
> +
> +	remove_cpu_topology(cpu);
> +	set_cpu_online(cpu, false);
> +	irq_migrate_all_off_this_cpu();
> +
> +	return ret;
> +}
> +
> +/*
> + * Called on the thread which is asking for a CPU to be shutdown.
> + */
> +void __cpu_die(unsigned int cpu)
> +{
> +	int ret = 0;
> +
> +	if (!cpu_wait_death(cpu, 5)) {
> +		pr_err("CPU %u: didn't die\n", cpu);
> +		return;
> +	}
> +	pr_notice("CPU%u: off\n", cpu);
> +
> +	/* Verify from the firmware if the cpu is really stopped*/
> +	if (cpu_ops[cpu]->cpu_is_stopped)
> +		ret = cpu_ops[cpu]->cpu_is_stopped(cpu);
> +	if (ret)
> +		pr_warn("CPU%d may not have stopped: %d\n", cpu, ret);
> +}
> +
> +/*
> + * Called from the idle thread for the CPU which has been shutdown.
> + */
> +void cpu_stop(void)
> +{
> +	idle_task_exit();
> +
> +	(void)cpu_report_death();
> +
> +	cpu_ops[smp_processor_id()]->cpu_stop();
> +	/* It should never reach here */
> +	BUG();
> +}
> diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
> index 66f3cded91f5..685fae72b7f5 100644
> --- a/arch/riscv/kernel/cpu_ops_sbi.c
> +++ b/arch/riscv/kernel/cpu_ops_sbi.c
> @@ -74,8 +74,42 @@ static int sbi_cpu_prepare(unsigned int cpuid)
>  	return 0;
>  }
>
> +#ifdef CONFIG_HOTPLUG_CPU
> +static int sbi_cpu_disable(unsigned int cpuid)
> +{
> +	if (!cpu_ops_sbi.cpu_stop)
> +		return -EOPNOTSUPP;
> +	return 0;
> +}
> +
> +static void sbi_cpu_stop(void)
> +{
> +	int ret;
> +
> +	ret = sbi_hsm_hart_stop();
> +	pr_crit("Unable to stop the cpu %u (%d)\n", smp_processor_id(), ret);
> +}
> +
> +static int sbi_cpu_is_stopped(unsigned int cpuid)
> +{
> +	int rc;
> +	int hartid = cpuid_to_hartid_map(cpuid);
> +
> +	rc = sbi_hsm_hart_get_status(hartid);
> +
> +	if (rc == SBI_HSM_HART_STATUS_STOPPED)
> +		return 0;
> +	return rc;
> +}
> +#endif
> +
>  const struct cpu_operations cpu_ops_sbi = {
>  	.name		= "sbi",
>  	.cpu_prepare	= sbi_cpu_prepare,
>  	.cpu_start	= sbi_cpu_start,
> +#ifdef CONFIG_HOTPLUG_CPU
> +	.cpu_disable	= sbi_cpu_disable,
> +	.cpu_stop	= sbi_cpu_stop,
> +	.cpu_is_stopped	= sbi_cpu_is_stopped,
> +#endif
>  };
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 44ac4ddf60ab..1d2f66579b94 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -16,12 +16,13 @@
>  #include <linux/of_platform.h>
>  #include <linux/sched/task.h>
>  #include <linux/swiotlb.h>
> +#include <linux/smp.h>
>
>  #include <asm/clint.h>
> +#include <asm/cpu_ops.h>
>  #include <asm/setup.h>
>  #include <asm/sections.h>
>  #include <asm/pgtable.h>
> -#include <asm/smp.h>
>  #include <asm/sbi.h>
>  #include <asm/tlbflush.h>
>  #include <asm/thread_info.h>
> @@ -43,6 +44,7 @@ struct screen_info screen_info = {
>  /* The lucky hart to first increment this variable will boot the other cores */
>  atomic_t hart_lottery;
>  unsigned long boot_cpu_hartid;
> +static DEFINE_PER_CPU(struct cpu, cpu_devices);
>
>  void __init parse_dtb(void)
>  {
> @@ -90,3 +92,18 @@ void __init setup_arch(char **cmdline_p)
>
>  	riscv_fill_hwcap();
>  }
> +
> +static int __init topology_init(void)
> +{
> +	int i;
> +
> +	for_each_possible_cpu(i) {
> +		struct cpu *cpu = &per_cpu(cpu_devices, i);
> +
> +		cpu->hotpluggable = cpu_has_hotplug(i);
> +		register_cpu(cpu, i);
> +	}
> +
> +	return 0;
> +}
> +subsys_initcall(topology_init);

Re: [PATCH v11 00/11] Add support for SBI v0.2 and CPU hotplug

[Palmer Dabbelt]

On Tue, 17 Mar 2020 18:11:33 PDT (-0700), Atish Patra wrote:
> The Supervisor Binary Interface(SBI) specification[1] now defines a
> base extension that provides extendability to add future extensions
> while maintaining backward compatibility with previous versions.
> The new version is defined as 0.2 and older version is marked as 0.1.

While 0.2 isn't official, I don't think we got any comments on 0.2-rc1 so let's
just go ahead and release it.  I'm hoping to send my PR at the end of the week,
I'll be sure to tag 0.2 before then -- things are still a bit of a mess here
due to the internet issues, but I've got a bunch of networking gear coming this
week so hopefully it'll get better...

Thanks for this!

>
> This series adds following features to RISC-V Linux.
> 1. Adds support for SBI v0.2
> 2. A Unified calling convention implementation between 0.1 and 0.2.
> 3. SBI Hart state management extension (HSM)
> 4. Ordered booting of harts
> 4. CPU hotplug
>
> Dependencies:
> The support for SBI v0.2 and HSM extension is already available in OpenSBI
> master.
>
> [1] https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc
>
> The patches are also available in following github repositery.
>
> Linux Kernel: https://github.com/atishp04/linux/tree/sbi_v0.2_v11
>
> Patches 1-5 implements the SBI v0.2 and unified calling convention.
> Patches 6-7 adds a cpu_ops method that allows different booting protocols
> dynamically.
> Patches 9-10 adds HSM extension and ordered hart booting support.
> Patche  11 adds cpu hotplug support.
>
> Changes v10->v11:
> 1. Addressed few nitpick comments.
> 2. Dropped plic patch as it is taken through IRQ tree.
>
> Changes from v9->10:
> 1. Minor copyright fixes.
> 2. Renaming of HSM extension definitions to match the spec.
>
> Changes from v8->v9:
> 1. Added a sliding window hart base method to support larger hart masks.
> 2. Added a callback to disable interrupts when cpu go offline.
> 3. Made the HSM extension series more modular.
>
> Changes from v7-v8:
> 1. Refactored to code to have modular cpu_ops calls.
> 2. Refactored HSM extension from sbi.c to cpu_ops_sbi.c.
> 3. Fix plic driver to handle cpu hotplug.
>
> Changes from v6-v7:
> 1. Rebased on v5.5
> 2. Fixed few compilation issues for !CONFIG_SMP and !CONFIG_RISCV_SBI
> 3. Added SBI HSM extension
> 4. Add CPU hotplug support
>
> Changes from v5->v6
> 1. Fixed few compilation issues around config.
> 2. Fixed hart mask generation issues for RFENCE & IPI extensions.
>
> Changes from v4->v5
> 1. Fixed few minor comments related to static & inline.
> 2. Make sure that every patch is boot tested individually.
>
> Changes from v3->v4.
> 1. Rebased on for-next.
> 2. Fixed issuses with checkpatch --strict.
> 3. Unfied all IPI/fence related functions.
> 4. Added Hfence related SBI calls.
>
> Changes from v2->v3.
> 1. Moved v0.1 extensions to a new config.
> 2. Added support for relacement extensions of v0.1 extensions.
>
> Changes from v1->v2
> 1. Removed the legacy calling convention.
> 2. Moved all SBI related calls to sbi.c.
> 3. Moved all SBI related macros to uapi.
>
> Atish Patra (11):
> RISC-V: Mark existing SBI as 0.1 SBI.
> RISC-V: Add basic support for SBI v0.2
> RISC-V: Add SBI v0.2 extension definitions
> RISC-V: Introduce a new config for SBI v0.1
> RISC-V: Implement new SBI v0.2 extensions
> RISC-V: Move relocate and few other functions out of __init
> RISC-V: Add cpu_ops and modify default booting method
> RISC-V: Export SBI error to linux error mapping function
> RISC-V: Add SBI HSM extension definitions
> RISC-V: Add supported for ordered booting method using HSM
> RISC-V: Support cpu hotplug
>
> arch/riscv/Kconfig                   |  19 +-
> arch/riscv/include/asm/cpu_ops.h     |  46 +++
> arch/riscv/include/asm/sbi.h         | 195 +++++----
> arch/riscv/include/asm/smp.h         |  24 ++
> arch/riscv/kernel/Makefile           |   6 +
> arch/riscv/kernel/cpu-hotplug.c      |  87 ++++
> arch/riscv/kernel/cpu_ops.c          |  46 +++
> arch/riscv/kernel/cpu_ops_sbi.c      | 115 ++++++
> arch/riscv/kernel/cpu_ops_spinwait.c |  43 ++
> arch/riscv/kernel/head.S             | 179 +++++----
> arch/riscv/kernel/sbi.c              | 575 ++++++++++++++++++++++++++-
> arch/riscv/kernel/setup.c            |  24 +-
> arch/riscv/kernel/smpboot.c          |  53 ++-
> arch/riscv/kernel/traps.c            |   2 +-
> arch/riscv/kernel/vmlinux.lds.S      |   5 +-
> 15 files changed, 1249 insertions(+), 170 deletions(-)
> create mode 100644 arch/riscv/include/asm/cpu_ops.h
> create mode 100644 arch/riscv/kernel/cpu-hotplug.c
> create mode 100644 arch/riscv/kernel/cpu_ops.c
> create mode 100644 arch/riscv/kernel/cpu_ops_sbi.c
> create mode 100644 arch/riscv/kernel/cpu_ops_spinwait.c

Re: [PATCH v11 00/11] Add support for SBI v0.2 and CPU hotplug

[Atish Patra]

On Tue, 2020-03-31 at 11:35 -0700, Palmer Dabbelt wrote:
> On Tue, 17 Mar 2020 18:11:33 PDT (-0700), Atish Patra wrote:
> > The Supervisor Binary Interface(SBI) specification[1] now defines a
> > base extension that provides extendability to add future extensions
> > while maintaining backward compatibility with previous versions.
> > The new version is defined as 0.2 and older version is marked as
> > 0.1.
> 
> While 0.2 isn't official, I don't think we got any comments on 0.2-
> rc1 so let's
> just go ahead and release it.  I'm hoping to send my PR at the end of
> the week,
> I'll be sure to tag 0.2 before then -- things are still a bit of a
> mess here
> due to the internet issues, but I've got a bunch of networking gear
> coming this
> week so hopefully it'll get better...
> 

Awesome. Thanks!

> Thanks for this!
> 
> > This series adds following features to RISC-V Linux.
> > 1. Adds support for SBI v0.2
> > 2. A Unified calling convention implementation between 0.1 and 0.2.
> > 3. SBI Hart state management extension (HSM)
> > 4. Ordered booting of harts
> > 4. CPU hotplug
> > 
> > Dependencies:
> > The support for SBI v0.2 and HSM extension is already available in
> > OpenSBI
> > master.
> > 
> > [1] 
> > https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc
> > 
> > The patches are also available in following github repositery.
> > 
> > Linux Kernel: https://github.com/atishp04/linux/tree/sbi_v0.2_v11
> > 
> > Patches 1-5 implements the SBI v0.2 and unified calling convention.
> > Patches 6-7 adds a cpu_ops method that allows different booting
> > protocols
> > dynamically.
> > Patches 9-10 adds HSM extension and ordered hart booting support.
> > Patche  11 adds cpu hotplug support.
> > 
> > Changes v10->v11:
> > 1. Addressed few nitpick comments.
> > 2. Dropped plic patch as it is taken through IRQ tree.
> > 
> > Changes from v9->10:
> > 1. Minor copyright fixes.
> > 2. Renaming of HSM extension definitions to match the spec.
> > 
> > Changes from v8->v9:
> > 1. Added a sliding window hart base method to support larger hart
> > masks.
> > 2. Added a callback to disable interrupts when cpu go offline.
> > 3. Made the HSM extension series more modular.
> > 
> > Changes from v7-v8:
> > 1. Refactored to code to have modular cpu_ops calls.
> > 2. Refactored HSM extension from sbi.c to cpu_ops_sbi.c.
> > 3. Fix plic driver to handle cpu hotplug.
> > 
> > Changes from v6-v7:
> > 1. Rebased on v5.5
> > 2. Fixed few compilation issues for !CONFIG_SMP and
> > !CONFIG_RISCV_SBI
> > 3. Added SBI HSM extension
> > 4. Add CPU hotplug support
> > 
> > Changes from v5->v6
> > 1. Fixed few compilation issues around config.
> > 2. Fixed hart mask generation issues for RFENCE & IPI extensions.
> > 
> > Changes from v4->v5
> > 1. Fixed few minor comments related to static & inline.
> > 2. Make sure that every patch is boot tested individually.
> > 
> > Changes from v3->v4.
> > 1. Rebased on for-next.
> > 2. Fixed issuses with checkpatch --strict.
> > 3. Unfied all IPI/fence related functions.
> > 4. Added Hfence related SBI calls.
> > 
> > Changes from v2->v3.
> > 1. Moved v0.1 extensions to a new config.
> > 2. Added support for relacement extensions of v0.1 extensions.
> > 
> > Changes from v1->v2
> > 1. Removed the legacy calling convention.
> > 2. Moved all SBI related calls to sbi.c.
> > 3. Moved all SBI related macros to uapi.
> > 
> > Atish Patra (11):
> > RISC-V: Mark existing SBI as 0.1 SBI.
> > RISC-V: Add basic support for SBI v0.2
> > RISC-V: Add SBI v0.2 extension definitions
> > RISC-V: Introduce a new config for SBI v0.1
> > RISC-V: Implement new SBI v0.2 extensions
> > RISC-V: Move relocate and few other functions out of __init
> > RISC-V: Add cpu_ops and modify default booting method
> > RISC-V: Export SBI error to linux error mapping function
> > RISC-V: Add SBI HSM extension definitions
> > RISC-V: Add supported for ordered booting method using HSM
> > RISC-V: Support cpu hotplug
> > 
> > arch/riscv/Kconfig                   |  19 +-
> > arch/riscv/include/asm/cpu_ops.h     |  46 +++
> > arch/riscv/include/asm/sbi.h         | 195 +++++----
> > arch/riscv/include/asm/smp.h         |  24 ++
> > arch/riscv/kernel/Makefile           |   6 +
> > arch/riscv/kernel/cpu-hotplug.c      |  87 ++++
> > arch/riscv/kernel/cpu_ops.c          |  46 +++
> > arch/riscv/kernel/cpu_ops_sbi.c      | 115 ++++++
> > arch/riscv/kernel/cpu_ops_spinwait.c |  43 ++
> > arch/riscv/kernel/head.S             | 179 +++++----
> > arch/riscv/kernel/sbi.c              | 575
> > ++++++++++++++++++++++++++-
> > arch/riscv/kernel/setup.c            |  24 +-
> > arch/riscv/kernel/smpboot.c          |  53 ++-
> > arch/riscv/kernel/traps.c            |   2 +-
> > arch/riscv/kernel/vmlinux.lds.S      |   5 +-
> > 15 files changed, 1249 insertions(+), 170 deletions(-)
> > create mode 100644 arch/riscv/include/asm/cpu_ops.h
> > create mode 100644 arch/riscv/kernel/cpu-hotplug.c
> > create mode 100644 arch/riscv/kernel/cpu_ops.c
> > create mode 100644 arch/riscv/kernel/cpu_ops_sbi.c
> > create mode 100644 arch/riscv/kernel/cpu_ops_spinwait.c

-- 
Regards,
Atish

Re: [PATCH v11 01/11] RISC-V: Mark existing SBI as 0.1 SBI.

[Bin Meng]

On Wed, Mar 18, 2020 at 9:11 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> As per the new SBI specification, current SBI implementation version
> is defined as 0.1 and will be removed/replaced in future. Each of the
> function call in 0.1 is defined as a separate extension which makes
> easier to replace them one at a time.
>
> Rename existing implementation to reflect that. This patch is just
> a preparatory patch for SBI v0.2 and doesn't introduce any functional
> changes.
>

nits: remove the ending period in the commit title

> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
> ---
>  arch/riscv/include/asm/sbi.h | 41 +++++++++++++++++++-----------------
>  1 file changed, 22 insertions(+), 19 deletions(-)

[snip]

Other than that,
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Re: [PATCH v11 02/11] RISC-V: Add basic support for SBI v0.2

[Bin Meng]

On Wed, Mar 18, 2020 at 9:11 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> The SBI v0.2 introduces a base extension which is backward compatible
> with v0.1. Implement all helper functions and minimum required SBI
> calls from v0.2 for now. All other base extension function will be
> added later as per need.
> As v0.2 calling convention is backward compatible with v0.1, remove
> the v0.1 helper functions and just use v0.2 calling convention.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
> ---
>  arch/riscv/include/asm/sbi.h | 139 ++++++++++----------
>  arch/riscv/kernel/sbi.c      | 243 ++++++++++++++++++++++++++++++++++-
>  arch/riscv/kernel/setup.c    |   5 +
>  3 files changed, 314 insertions(+), 73 deletions(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Re: [PATCH v11 03/11] RISC-V: Add SBI v0.2 extension definitions

[Bin Meng]

On Wed, Mar 18, 2020 at 9:11 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> Few v0.1 SBI calls are being replaced by new SBI calls that follows
> v0.2 calling convention.
>
> This patch just defines these new extensions.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
> ---
>  arch/riscv/include/asm/sbi.h | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Re: [PATCH v11 04/11] RISC-V: Introduce a new config for SBI v0.1

[Bin Meng]

On Wed, Mar 18, 2020 at 9:11 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> We now have SBI v0.2 which is more scalable and extendable to handle
> future needs for RISC-V supervisor interfaces.
>
> Introduce a new config and move all SBI v0.1 code under that config.
> This allows to implement the new replacement SBI extensions cleanly
> and remove v0.1 extensions easily in future. Currently, the config
> is enabled by default. Once all M-mode software, with v0.1, is no
> longer in use, this config option and all relevant code can be easily
> removed.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> ---
>  arch/riscv/Kconfig           |   7 ++
>  arch/riscv/include/asm/sbi.h |   2 +
>  arch/riscv/kernel/sbi.c      | 132 +++++++++++++++++++++++++++++------
>  3 files changed, 118 insertions(+), 23 deletions(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Re: [PATCH v11 05/11] RISC-V: Implement new SBI v0.2 extensions

[Bin Meng]

On Wed, Mar 18, 2020 at 9:11 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> Few v0.1 SBI calls are being replaced by new SBI calls that follows v0.2
> calling convention.
>
> Implement the replacement extensions and few additional new SBI function calls
> that makes way for a better SBI interface in future.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> ---
>  arch/riscv/include/asm/sbi.h |  14 ++
>  arch/riscv/include/asm/smp.h |   7 +
>  arch/riscv/kernel/sbi.c      | 253 ++++++++++++++++++++++++++++++++++-
>  3 files changed, 270 insertions(+), 4 deletions(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Re: [PATCH v11 08/11] RISC-V: Export SBI error to linux error mapping function

[Bin Meng]

On Wed, Mar 18, 2020 at 9:12 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> All SBI related extensions will not be implemented in sbi.c to avoid
> bloating. Thus, sbi_err_map_linux_errno() will be used in other files
> implementing that specific extension.
>
> Export the function so that it can be used later.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup.patel@wdc.com>
> ---
>  arch/riscv/include/asm/sbi.h | 2 ++
>  arch/riscv/kernel/sbi.c      | 3 ++-
>  2 files changed, 4 insertions(+), 1 deletion(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Re: [PATCH v11 09/11] RISC-V: Add SBI HSM extension definitions

[Bin Meng]

On Wed, Mar 18, 2020 at 9:12 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> SBI specification defines HSM extension that allows to start/stop a hart
> by a supervisor anytime. The specification is available at
>
> https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc
>
> Add those definitions here.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup.patel@wdc.com>
> ---
>  arch/riscv/include/asm/sbi.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Re: [PATCH v11 10/11] RISC-V: Add supported for ordered booting method using HSM

[Bin Meng]

On Wed, Mar 18, 2020 at 9:12 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> Currently, all harts have to jump Linux in RISC-V. This complicates the
> multi-stage boot process as every transient stage also has to ensure all
> harts enter to that stage and jump to Linux afterwards. It also obstructs
> a clean Kexec implementation.
>
> SBI HSM extension provides alternate solutions where only a single hart
> need to boot and enter Linux. The booting hart can bring up secondary
> harts one by one afterwards.
>
> Add SBI HSM based cpu_ops that implements an ordered booting method in
> RISC-V. This change is also backward compatible with older firmware not
> implementing HSM extension. If a latest kernel is used with older
> firmware, it will continue to use the default spinning booting method.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> ---
>  arch/riscv/kernel/Makefile      |  3 ++
>  arch/riscv/kernel/cpu_ops.c     | 10 +++-
>  arch/riscv/kernel/cpu_ops_sbi.c | 81 +++++++++++++++++++++++++++++++++
>  arch/riscv/kernel/head.S        | 26 +++++++++++
>  arch/riscv/kernel/smpboot.c     |  2 +-
>  arch/riscv/kernel/traps.c       |  2 +-
>  6 files changed, 121 insertions(+), 3 deletions(-)
>  create mode 100644 arch/riscv/kernel/cpu_ops_sbi.c
>
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index f81a6ff88005..a0be34b96846 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -44,5 +44,8 @@ obj-$(CONFIG_PERF_EVENTS)     += perf_event.o
>  obj-$(CONFIG_PERF_EVENTS)      += perf_callchain.o
>  obj-$(CONFIG_HAVE_PERF_REGS)   += perf_regs.o
>  obj-$(CONFIG_RISCV_SBI)                += sbi.o
> +ifeq ($(CONFIG_RISCV_SBI), y)
> +obj-$(CONFIG_SMP) += cpu_ops_sbi.o
> +endif
>
>  clean:
> diff --git a/arch/riscv/kernel/cpu_ops.c b/arch/riscv/kernel/cpu_ops.c
> index 62705908eee5..c4c33bf02369 100644
> --- a/arch/riscv/kernel/cpu_ops.c
> +++ b/arch/riscv/kernel/cpu_ops.c
> @@ -18,6 +18,7 @@ const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
>  void *__cpu_up_stack_pointer[NR_CPUS];
>  void *__cpu_up_task_pointer[NR_CPUS];
>
> +extern const struct cpu_operations cpu_ops_sbi;
>  extern const struct cpu_operations cpu_ops_spinwait;
>
>  void cpu_update_secondary_bootdata(unsigned int cpuid,
> @@ -34,5 +35,12 @@ void cpu_update_secondary_bootdata(unsigned int cpuid,
>
>  void __init cpu_set_ops(int cpuid)
>  {
> -       cpu_ops[cpuid] = &cpu_ops_spinwait;
> +#if IS_ENABLED(CONFIG_RISCV_SBI)
> +       if (sbi_probe_extension(SBI_EXT_HSM) > 0) {
> +               if (!cpuid)
> +                       pr_info("SBI v0.2 HSM extension detected\n");
> +               cpu_ops[cpuid] = &cpu_ops_sbi;
> +       } else
> +#endif
> +               cpu_ops[cpuid] = &cpu_ops_spinwait;
>  }
> diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
> new file mode 100644
> index 000000000000..66f3cded91f5
> --- /dev/null
> +++ b/arch/riscv/kernel/cpu_ops_sbi.c
> @@ -0,0 +1,81 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * HSM extension and cpu_ops implementation.
> + *
> + * Copyright (c) 2020 Western Digital Corporation or its affiliates.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/mm.h>
> +#include <asm/cpu_ops.h>
> +#include <asm/sbi.h>
> +#include <asm/smp.h>
> +
> +extern char secondary_start_sbi[];
> +const struct cpu_operations cpu_ops_sbi;
> +
> +static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr,
> +                             unsigned long priv)
> +{
> +       struct sbiret ret;
> +
> +       ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
> +                       hartid, saddr, priv, 0, 0, 0);
> +       if (ret.error)
> +               return sbi_err_map_linux_errno(ret.error);
> +       else
> +               return 0;
> +}
> +
> +#ifdef CONFIG_HOTPLUG_CPU
> +static int sbi_hsm_hart_stop(void)
> +{
> +       struct sbiret ret;
> +
> +       ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STOP, 0, 0, 0, 0, 0, 0);
> +
> +       if (ret.error)
> +               return sbi_err_map_linux_errno(ret.error);
> +       else
> +               return 0;
> +}
> +
> +static int sbi_hsm_hart_get_status(unsigned long hartid)
> +{
> +       struct sbiret ret;
> +
> +       ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STATUS,
> +                       hartid, 0, 0, 0, 0, 0);
> +       if (ret.error)
> +               return sbi_err_map_linux_errno(ret.error);
> +       else
> +               return ret.value;
> +}
> +#endif
> +
> +static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle)
> +{
> +       int rc;
> +       unsigned long boot_addr = __pa_symbol(secondary_start_sbi);
> +       int hartid = cpuid_to_hartid_map(cpuid);
> +
> +       cpu_update_secondary_bootdata(cpuid, tidle);
> +       rc = sbi_hsm_hart_start(hartid, boot_addr, 0);
> +
> +       return rc;
> +}
> +
> +static int sbi_cpu_prepare(unsigned int cpuid)
> +{
> +       if (!cpu_ops_sbi.cpu_start) {
> +               pr_err("cpu start method not defined for CPU [%d]\n", cpuid);
> +               return -ENODEV;
> +       }
> +       return 0;
> +}
> +
> +const struct cpu_operations cpu_ops_sbi = {
> +       .name           = "sbi",
> +       .cpu_prepare    = sbi_cpu_prepare,
> +       .cpu_start      = sbi_cpu_start,
> +};
> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> index 173507395a6b..e5115d5e0b3a 100644
> --- a/arch/riscv/kernel/head.S
> +++ b/arch/riscv/kernel/head.S
> @@ -99,11 +99,37 @@ relocate:
>         ret
>  #endif /* CONFIG_MMU */
>  #ifdef CONFIG_SMP
> +       .global secondary_start_sbi
> +secondary_start_sbi:
> +       /* Mask all interrupts */
> +       csrw CSR_IE, zero
> +       csrw CSR_IP, zero
> +
> +       /* Load the global pointer */
> +       .option push
> +       .option norelax
> +               la gp, __global_pointer$

Is this line's indentation level intended?

> +       .option pop
> +
> +       /*
> +        * Disable FPU to detect illegal usage of
> +        * floating point in kernel space
> +        */
> +       li t0, SR_FS
> +       csrc CSR_STATUS, t0
> +
>         /* Set trap vector to spin forever to help debug */
>         la a3, .Lsecondary_park
>         csrw CSR_TVEC, a3
>
>         slli a3, a0, LGREG
> +       la a4, __cpu_up_stack_pointer
> +       la a5, __cpu_up_task_pointer
> +       add a4, a3, a4
> +       add a5, a3, a5
> +       REG_L sp, (a4)
> +       REG_L tp, (a5)
> +
>         .global secondary_start_common
>  secondary_start_common:
>
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index e89396a2a1af..4e9922790f6e 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -143,7 +143,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
>  /*
>   * C entry point for a secondary processor.
>   */
> -asmlinkage __visible void __init smp_callin(void)
> +asmlinkage __visible void smp_callin(void)
>  {
>         struct mm_struct *mm = &init_mm;
>
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index ffb3d94bf0cc..8e13ad45ccaa 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -147,7 +147,7 @@ int is_valid_bugaddr(unsigned long pc)
>  }
>  #endif /* CONFIG_GENERIC_BUG */
>
> -void __init trap_init(void)
> +void trap_init(void)
>  {
>         /*
>          * Set sup0 scratch register to 0, indicating to exception vector

Should the above 2 be moved to patch [06/11] RISC-V: Move relocate and
few other functions out of __init ?

Other than that,
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Regards,
Bin