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* [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs
@ 2020-07-14  7:40 Emil Renner Berthing
  2020-07-14  7:40 ` [PATCH v3 2/2] riscv: Add jump-label implementation Emil Renner Berthing
  2020-07-21  0:54 ` [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs Palmer Dabbelt
  0 siblings, 2 replies; 3+ messages in thread
From: Emil Renner Berthing @ 2020-07-14  7:40 UTC (permalink / raw)
  To: linux-riscv
  Cc: Emil Renner Berthing, Palmer Dabbelt, Björn Töpel,
	Paul Walmsley, Jonathan Corbet, linux-doc, linux-kernel

These are needed for the __jump_table in modules using
static keys/jump-labels with the layout from
HAVE_ARCH_JUMP_LABEL_RELATIVE on 64bit kernels.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Björn Töpel <bjorn.topel@gmail.com>
Tested-by: Björn Töpel <bjorn.topel@gmail.com>
---
Tested on the HiFive Unleashed board.

No changes since v2.

This patch is new in v2. It fixes an error loading modules
containing static keys found by Björn Töpel.

 arch/riscv/kernel/module.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 7191342c54da..104fba889cf7 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -263,6 +263,13 @@ static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
 	return 0;
 }
 
+static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
+				    Elf_Addr v)
+{
+	*(u64 *)location += (u64)v;
+	return 0;
+}
+
 static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
 				    Elf_Addr v)
 {
@@ -270,6 +277,13 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
 	return 0;
 }
 
+static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
+				    Elf_Addr v)
+{
+	*(u64 *)location -= (u64)v;
+	return 0;
+}
+
 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
 				Elf_Addr v) = {
 	[R_RISCV_32]			= apply_r_riscv_32_rela,
@@ -290,7 +304,9 @@ static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
 	[R_RISCV_RELAX]			= apply_r_riscv_relax_rela,
 	[R_RISCV_ALIGN]			= apply_r_riscv_align_rela,
 	[R_RISCV_ADD32]			= apply_r_riscv_add32_rela,
+	[R_RISCV_ADD64]			= apply_r_riscv_add64_rela,
 	[R_RISCV_SUB32]			= apply_r_riscv_sub32_rela,
+	[R_RISCV_SUB64]			= apply_r_riscv_sub64_rela,
 };
 
 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
-- 
2.27.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH v3 2/2] riscv: Add jump-label implementation
  2020-07-14  7:40 [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs Emil Renner Berthing
@ 2020-07-14  7:40 ` Emil Renner Berthing
  2020-07-21  0:54 ` [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs Palmer Dabbelt
  1 sibling, 0 replies; 3+ messages in thread
From: Emil Renner Berthing @ 2020-07-14  7:40 UTC (permalink / raw)
  To: linux-riscv
  Cc: Emil Renner Berthing, Palmer Dabbelt, Björn Töpel,
	Paul Walmsley, Jonathan Corbet, linux-doc, linux-kernel

Add jump-label implementation based on the ARM64 version
and add CONFIG_JUMP_LABEL=y to the defconfigs.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Björn Töpel <bjorn.topel@gmail.com>
Tested-by: Björn Töpel <bjorn.topel@gmail.com>
---
Tested on the HiFive Unleashed board.

Changes since v2:
- Add missing asm/asm.h include.
  Reported-by: kernel test robot <lkp@intel.com>

Changes since v1:
- WARN and give up gracefully if the jump offset cannot be
  represented in a JAL instruction.
- Add missing braces.
- Add CONFIG_JUMP_LABEL=y to defconfigs.

All suggested by Björn Töpel.

Changes since RFC:
- Use RISCV_PTR and RISCV_LGPTR macros to match struct jump_table
  also in 32bit kernels.
- Remove unneeded branch ? 1 : 0, thanks Björn
- Fix \n\n instead of \n\t mistake

 .../core/jump-labels/arch-support.txt         |  2 +-
 arch/riscv/Kconfig                            |  2 +
 arch/riscv/configs/defconfig                  |  1 +
 arch/riscv/configs/nommu_k210_defconfig       |  1 +
 arch/riscv/configs/nommu_virt_defconfig       |  1 +
 arch/riscv/configs/rv32_defconfig             |  1 +
 arch/riscv/include/asm/jump_label.h           | 60 +++++++++++++++++++
 arch/riscv/kernel/Makefile                    |  2 +
 arch/riscv/kernel/jump_label.c                | 49 +++++++++++++++
 9 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/jump_label.h
 create mode 100644 arch/riscv/kernel/jump_label.c

diff --git a/Documentation/features/core/jump-labels/arch-support.txt b/Documentation/features/core/jump-labels/arch-support.txt
index 632a1c7aefa2..760243d18ed7 100644
--- a/Documentation/features/core/jump-labels/arch-support.txt
+++ b/Documentation/features/core/jump-labels/arch-support.txt
@@ -23,7 +23,7 @@
     |    openrisc: | TODO |
     |      parisc: |  ok  |
     |     powerpc: |  ok  |
-    |       riscv: | TODO |
+    |       riscv: |  ok  |
     |        s390: |  ok  |
     |          sh: | TODO |
     |       sparc: |  ok  |
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index c6d4f7771bff..3beb844c5951 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -48,6 +48,8 @@ config RISCV
 	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
 	select HANDLE_DOMAIN_IRQ
 	select HAVE_ARCH_AUDITSYSCALL
+	select HAVE_ARCH_JUMP_LABEL
+	select HAVE_ARCH_JUMP_LABEL_RELATIVE
 	select HAVE_ARCH_KASAN if MMU && 64BIT
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_KGDB_QXFER_PKT
diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
index 4da4886246a4..d58c93efb603 100644
--- a/arch/riscv/configs/defconfig
+++ b/arch/riscv/configs/defconfig
@@ -17,6 +17,7 @@ CONFIG_BPF_SYSCALL=y
 CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
+CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_NET=y
diff --git a/arch/riscv/configs/nommu_k210_defconfig b/arch/riscv/configs/nommu_k210_defconfig
index b48138e329ea..cd1df62b13c7 100644
--- a/arch/riscv/configs/nommu_k210_defconfig
+++ b/arch/riscv/configs/nommu_k210_defconfig
@@ -33,6 +33,7 @@ CONFIG_SMP=y
 CONFIG_NR_CPUS=2
 CONFIG_CMDLINE="earlycon console=ttySIF0"
 CONFIG_CMDLINE_FORCE=y
+CONFIG_JUMP_LABEL=y
 # CONFIG_BLOCK is not set
 CONFIG_BINFMT_FLAT=y
 # CONFIG_COREDUMP is not set
diff --git a/arch/riscv/configs/nommu_virt_defconfig b/arch/riscv/configs/nommu_virt_defconfig
index cf74e179bf90..f27596e9663e 100644
--- a/arch/riscv/configs/nommu_virt_defconfig
+++ b/arch/riscv/configs/nommu_virt_defconfig
@@ -30,6 +30,7 @@ CONFIG_MAXPHYSMEM_2GB=y
 CONFIG_SMP=y
 CONFIG_CMDLINE="root=/dev/vda rw earlycon=uart8250,mmio,0x10000000,115200n8 console=ttyS0"
 CONFIG_CMDLINE_FORCE=y
+CONFIG_JUMP_LABEL=y
 # CONFIG_BLK_DEV_BSG is not set
 CONFIG_PARTITION_ADVANCED=y
 # CONFIG_MSDOS_PARTITION is not set
diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
index 05bbf5240569..3a55f0e00d6c 100644
--- a/arch/riscv/configs/rv32_defconfig
+++ b/arch/riscv/configs/rv32_defconfig
@@ -17,6 +17,7 @@ CONFIG_BPF_SYSCALL=y
 CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
+CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_NET=y
diff --git a/arch/riscv/include/asm/jump_label.h b/arch/riscv/include/asm/jump_label.h
new file mode 100644
index 000000000000..38af2ec7b9bf
--- /dev/null
+++ b/arch/riscv/include/asm/jump_label.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 Emil Renner Berthing
+ *
+ * Based on arch/arm64/include/asm/jump_label.h
+ */
+#ifndef __ASM_JUMP_LABEL_H
+#define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <asm/asm.h>
+
+#define JUMP_LABEL_NOP_SIZE 4
+
+static __always_inline bool arch_static_branch(struct static_key *key,
+					       bool branch)
+{
+	asm_volatile_goto(
+		"	.option push				\n\t"
+		"	.option norelax				\n\t"
+		"	.option norvc				\n\t"
+		"1:	nop					\n\t"
+		"	.option pop				\n\t"
+		"	.pushsection	__jump_table, \"aw\"	\n\t"
+		"	.align		" RISCV_LGPTR "		\n\t"
+		"	.long		1b - ., %l[label] - .	\n\t"
+		"	" RISCV_PTR "	%0 - .			\n\t"
+		"	.popsection				\n\t"
+		:  :  "i"(&((char *)key)[branch]) :  : label);
+
+	return false;
+label:
+	return true;
+}
+
+static __always_inline bool arch_static_branch_jump(struct static_key *key,
+						    bool branch)
+{
+	asm_volatile_goto(
+		"	.option push				\n\t"
+		"	.option norelax				\n\t"
+		"	.option norvc				\n\t"
+		"1:	jal		zero, %l[label]		\n\t"
+		"	.option pop				\n\t"
+		"	.pushsection	__jump_table, \"aw\"	\n\t"
+		"	.align		" RISCV_LGPTR "		\n\t"
+		"	.long		1b - ., %l[label] - .	\n\t"
+		"	" RISCV_PTR "	%0 - .			\n\t"
+		"	.popsection				\n\t"
+		:  :  "i"(&((char *)key)[branch]) :  : label);
+
+	return false;
+label:
+	return true;
+}
+
+#endif  /* __ASSEMBLY__ */
+#endif	/* __ASM_JUMP_LABEL_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index b355cf485671..a5287ab9f7f2 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -53,4 +53,6 @@ endif
 obj-$(CONFIG_HOTPLUG_CPU)	+= cpu-hotplug.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 
+obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
+
 clean:
diff --git a/arch/riscv/kernel/jump_label.c b/arch/riscv/kernel/jump_label.c
new file mode 100644
index 000000000000..1bab1abc1aa5
--- /dev/null
+++ b/arch/riscv/kernel/jump_label.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Emil Renner Berthing
+ *
+ * Based on arch/arm64/kernel/jump_label.c
+ */
+#include <linux/kernel.h>
+#include <linux/jump_label.h>
+#include <asm/bug.h>
+#include <asm/patch.h>
+
+#define RISCV_INSN_NOP 0x00000013U
+#define RISCV_INSN_JAL 0x0000006fU
+
+void arch_jump_label_transform(struct jump_entry *entry,
+			       enum jump_label_type type)
+{
+	void *addr = (void *)jump_entry_code(entry);
+	u32 insn;
+
+	if (type == JUMP_LABEL_JMP) {
+		long offset = jump_entry_target(entry) - jump_entry_code(entry);
+
+		if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
+			return;
+
+		insn = RISCV_INSN_JAL |
+			(((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
+			(((u32)offset & GENMASK(11, 11)) << (20 - 11)) |
+			(((u32)offset & GENMASK(10,  1)) << (21 -  1)) |
+			(((u32)offset & GENMASK(20, 20)) << (31 - 20));
+	} else {
+		insn = RISCV_INSN_NOP;
+	}
+
+	patch_text_nosync(addr, &insn, sizeof(insn));
+}
+
+void arch_jump_label_transform_static(struct jump_entry *entry,
+				      enum jump_label_type type)
+{
+	/*
+	 * We use the same instructions in the arch_static_branch and
+	 * arch_static_branch_jump inline functions, so there's no
+	 * need to patch them up here.
+	 * The core will call arch_jump_label_transform  when those
+	 * instructions need to be replaced.
+	 */
+}
-- 
2.27.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs
  2020-07-14  7:40 [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs Emil Renner Berthing
  2020-07-14  7:40 ` [PATCH v3 2/2] riscv: Add jump-label implementation Emil Renner Berthing
@ 2020-07-21  0:54 ` Palmer Dabbelt
  1 sibling, 0 replies; 3+ messages in thread
From: Palmer Dabbelt @ 2020-07-21  0:54 UTC (permalink / raw)
  To: kernel
  Cc: linux-riscv, kernel, Bjorn Topel, Paul Walmsley, corbet,
	linux-doc, linux-kernel

On Tue, 14 Jul 2020 00:40:43 PDT (-0700), kernel@esmil.dk wrote:
> These are needed for the __jump_table in modules using
> static keys/jump-labels with the layout from
> HAVE_ARCH_JUMP_LABEL_RELATIVE on 64bit kernels.
>
> Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
> Reviewed-by: Björn Töpel <bjorn.topel@gmail.com>
> Tested-by: Björn Töpel <bjorn.topel@gmail.com>

These are on for-next.  Thanks!

> ---
> Tested on the HiFive Unleashed board.
>
> No changes since v2.
>
> This patch is new in v2. It fixes an error loading modules
> containing static keys found by Björn Töpel.
>
>  arch/riscv/kernel/module.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
> index 7191342c54da..104fba889cf7 100644
> --- a/arch/riscv/kernel/module.c
> +++ b/arch/riscv/kernel/module.c
> @@ -263,6 +263,13 @@ static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
>  	return 0;
>  }
>
> +static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
> +				    Elf_Addr v)
> +{
> +	*(u64 *)location += (u64)v;
> +	return 0;
> +}
> +
>  static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
>  				    Elf_Addr v)
>  {
> @@ -270,6 +277,13 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
>  	return 0;
>  }
>
> +static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
> +				    Elf_Addr v)
> +{
> +	*(u64 *)location -= (u64)v;
> +	return 0;
> +}
> +
>  static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
>  				Elf_Addr v) = {
>  	[R_RISCV_32]			= apply_r_riscv_32_rela,
> @@ -290,7 +304,9 @@ static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
>  	[R_RISCV_RELAX]			= apply_r_riscv_relax_rela,
>  	[R_RISCV_ALIGN]			= apply_r_riscv_align_rela,
>  	[R_RISCV_ADD32]			= apply_r_riscv_add32_rela,
> +	[R_RISCV_ADD64]			= apply_r_riscv_add64_rela,
>  	[R_RISCV_SUB32]			= apply_r_riscv_sub32_rela,
> +	[R_RISCV_SUB64]			= apply_r_riscv_sub64_rela,
>  };
>
>  int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, back to index

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-14  7:40 [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs Emil Renner Berthing
2020-07-14  7:40 ` [PATCH v3 2/2] riscv: Add jump-label implementation Emil Renner Berthing
2020-07-21  0:54 ` [PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs Palmer Dabbelt

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