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[PATCH v2 2/2] openrisc: Add jump label support

ChenMiao posted 2 patches 2 months ago
[PATCH v2 2/2] openrisc: Add jump label support
Posted by ChenMiao 2 months ago 
From: chenmiao <chenmiao.ku@gmail.com>

Implemented the full functionality of jump_label, of course,
with text patching supported by just one API.

By the way, add new macro OPENRISC_INSN_NOP in insn-def.h to use.

- V2: using the patch_insn_write(void *addr, u32 insn) not the
const void *insn.

Link: https://lore.kernel.org/openrisc/aJIC8o1WmVHol9RY@antec/T/#t

Signed-off-by: chenmiao <chenmiao.ku@gmail.com>
---
 .../core/jump-labels/arch-support.txt         |  2 +-
 arch/openrisc/Kconfig                         |  2 +
 arch/openrisc/configs/or1ksim_defconfig       | 19 ++----
 arch/openrisc/configs/virt_defconfig          |  1 +
 arch/openrisc/include/asm/insn-def.h          |  3 +
 arch/openrisc/include/asm/jump_label.h        | 68 +++++++++++++++++++
 arch/openrisc/kernel/Makefile                 |  1 +
 arch/openrisc/kernel/jump_label.c             | 53 +++++++++++++++
 arch/openrisc/kernel/setup.c                  |  2 +
 9 files changed, 138 insertions(+), 13 deletions(-)
 create mode 100644 arch/openrisc/include/asm/jump_label.h
 create mode 100644 arch/openrisc/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 ccada815569f..683de7c15058 100644
--- a/Documentation/features/core/jump-labels/arch-support.txt
+++ b/Documentation/features/core/jump-labels/arch-support.txt
@@ -17,7 +17,7 @@
     |  microblaze: | TODO |
     |        mips: |  ok  |
     |       nios2: | TODO |
-    |    openrisc: | TODO |
+    |    openrisc: |  ok  |
     |      parisc: |  ok  |
     |     powerpc: |  ok  |
     |       riscv: |  ok  |
diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index b38fee299bc4..9156635dd264 100644
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -24,6 +24,8 @@ config OPENRISC
 	select GENERIC_PCI_IOMAP
 	select GENERIC_IOREMAP
 	select GENERIC_CPU_DEVICES
+	select HAVE_ARCH_JUMP_LABEL
+	select HAVE_ARCH_JUMP_LABEL_RELATIVE
 	select HAVE_PCI
 	select HAVE_UID16
 	select HAVE_PAGE_SIZE_8KB
diff --git a/arch/openrisc/configs/or1ksim_defconfig b/arch/openrisc/configs/or1ksim_defconfig
index 59fe33cefba2..769705ac24d5 100644
--- a/arch/openrisc/configs/or1ksim_defconfig
+++ b/arch/openrisc/configs/or1ksim_defconfig
@@ -3,26 +3,23 @@ CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
 # CONFIG_RD_GZIP is not set
 CONFIG_EXPERT=y
-# CONFIG_KALLSYMS is not set
 # CONFIG_EPOLL is not set
 # CONFIG_TIMERFD is not set
 # CONFIG_EVENTFD is not set
 # CONFIG_AIO is not set
-# CONFIG_VM_EVENT_COUNTERS is not set
-# CONFIG_COMPAT_BRK is not set
-CONFIG_SLUB=y
-CONFIG_SLUB_TINY=y
-CONFIG_MODULES=y
-# CONFIG_BLOCK is not set
+# CONFIG_KALLSYMS is not set
 CONFIG_BUILTIN_DTB_NAME="or1ksim"
 CONFIG_HZ_100=y
+CONFIG_JUMP_LABEL=y
+CONFIG_MODULES=y
+# CONFIG_BLOCK is not set
+CONFIG_SLUB_TINY=y
+# CONFIG_COMPAT_BRK is not set
+# CONFIG_VM_EVENT_COUNTERS is not set
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y
 CONFIG_INET=y
-# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
-# CONFIG_INET_XFRM_MODE_TUNNEL is not set
-# CONFIG_INET_XFRM_MODE_BEET is not set
 # CONFIG_INET_DIAG is not set
 CONFIG_TCP_CONG_ADVANCED=y
 # CONFIG_TCP_CONG_BIC is not set
@@ -35,7 +32,6 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 # CONFIG_PREVENT_FIRMWARE_BUILD is not set
 # CONFIG_FW_LOADER is not set
-CONFIG_PROC_DEVICETREE=y
 CONFIG_NETDEVICES=y
 CONFIG_ETHOC=y
 CONFIG_MICREL_PHY=y
@@ -53,4 +49,3 @@ CONFIG_SERIAL_OF_PLATFORM=y
 # CONFIG_DNOTIFY is not set
 CONFIG_TMPFS=y
 CONFIG_NFS_FS=y
-# CONFIG_ENABLE_MUST_CHECK is not set
diff --git a/arch/openrisc/configs/virt_defconfig b/arch/openrisc/configs/virt_defconfig
index c1b69166c500..4a80c5794877 100644
--- a/arch/openrisc/configs/virt_defconfig
+++ b/arch/openrisc/configs/virt_defconfig
@@ -12,6 +12,7 @@ CONFIG_NR_CPUS=8
 CONFIG_SMP=y
 CONFIG_HZ_100=y
 # CONFIG_OPENRISC_NO_SPR_SR_DSX is not set
+CONFIG_JUMP_LABEL=y
 # CONFIG_COMPAT_BRK is not set
 CONFIG_NET=y
 CONFIG_PACKET=y
diff --git a/arch/openrisc/include/asm/insn-def.h b/arch/openrisc/include/asm/insn-def.h
index dc8d16db1579..2ccdbb37c27c 100644
--- a/arch/openrisc/include/asm/insn-def.h
+++ b/arch/openrisc/include/asm/insn-def.h
@@ -9,4 +9,7 @@
 /* or1k instructions are always 32 bits. */
 #define	OPENRISC_INSN_SIZE		4
 
+/* or1k nop instruction code */
+#define OPENRISC_INSN_NOP     0x15000000U
+
 #endif /* __ASM_INSN_DEF_H */
diff --git a/arch/openrisc/include/asm/jump_label.h b/arch/openrisc/include/asm/jump_label.h
new file mode 100644
index 000000000000..03afca9c3a1f
--- /dev/null
+++ b/arch/openrisc/include/asm/jump_label.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2025 Chen Miao
+ *
+ * Based on arch/arm/include/asm/jump_label.h
+ */
+#ifndef __ASM_JUMP_LABEL_H
+#define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <asm/insn-def.h>
+
+#define HAVE_JUMP_LABEL_BATCH
+
+#define JUMP_LABEL_NOP_SIZE OPENRISC_INSN_SIZE
+
+/*
+ * should aligned 4
+ * for jump_label relative
+ * entry.code   = nop.addr - . -> return false
+ * entry.target = l_yes - .    -> return true
+ * entry.key	= key - .
+ */
+#define JUMP_TABLE_ENTRY(key, label)			\
+	".pushsection	__jump_table, \"aw\"	\n\t"	\
+	".align 	4 			\n\t"	\
+	".long 		1b - ., " label " - .	\n\t"	\
+	".long 		" key " - . 		\n\t"	\
+	".popsection				\n\t"
+
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	".align		4			\n\t"	\
+	"1: l.nop				\n\t"	\
+	"    l.nop				\n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
+
+static __always_inline bool arch_static_branch(struct static_key *const key,
+					       const bool branch)
+{
+	asm goto (ARCH_STATIC_BRANCH_ASM("%0", "%l[l_yes]")
+		  ::"i"(&((char *)key)[branch])::l_yes);
+
+	return false;
+l_yes:
+	return true;
+}
+
+#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label)		\
+	".align		4			\n\t"	\
+	"1: l.j	" label "			\n\t"	\
+	"    l.nop				\n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
+
+static __always_inline bool
+arch_static_branch_jump(struct static_key *const key, const bool branch)
+{
+	asm goto (ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[l_yes]")
+		  ::"i"(&((char *)key)[branch])::l_yes);
+
+	return false;
+l_yes:
+	return true;
+}
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_JUMP_LABEL_H */
diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
index f0957ce16d6b..19e0eb94f2eb 100644
--- a/arch/openrisc/kernel/Makefile
+++ b/arch/openrisc/kernel/Makefile
@@ -9,6 +9,7 @@ obj-y	:= head.o setup.o or32_ksyms.o process.o dma.o \
 	   traps.o time.o irq.o entry.o ptrace.o signal.o \
 	   sys_call_table.o unwinder.o cacheinfo.o
 
+obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 obj-$(CONFIG_SMP)		+= smp.o sync-timer.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_MODULES)		+= module.o
diff --git a/arch/openrisc/kernel/jump_label.c b/arch/openrisc/kernel/jump_label.c
new file mode 100644
index 000000000000..ce259ba30258
--- /dev/null
+++ b/arch/openrisc/kernel/jump_label.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 Chen Miao
+ *
+ * Based on arch/arm/kernel/jump_label.c
+ */
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <asm/bug.h>
+#include <asm/cacheflush.h>
+#include <asm/text-patching.h>
+
+bool arch_jump_label_transform_queue(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;
+
+		offset = jump_entry_target(entry) - jump_entry_code(entry);
+		/*
+		 * The actual maximum range of the l.j instruction's offset is -134,217,728
+		 * ~ 134,217,724 (sign 26-bit imm).
+		 * For the original jump range, we need to right-shift N by 2 to obtain the
+		 * instruction's offset.
+		 */
+		if (unlikely(offset < -134217728 || offset > 134217724)) {
+			WARN_ON_ONCE(true);
+		}
+		/* 26bit imm mask */
+		offset = (offset >> 2) & 0x03ffffff;
+
+		insn = offset;
+	} else {
+		insn = OPENRISC_INSN_NOP;
+	}
+
+	if (early_boot_irqs_disabled) {
+		copy_to_kernel_nofault(addr, &insn, sizeof(insn));
+	} else {
+		patch_insn_write(addr, insn);
+	}
+	return true;
+}
+
+void arch_jump_label_transform_apply(void)
+{
+	// flush
+	kick_all_cpus_sync();
+}
diff --git a/arch/openrisc/kernel/setup.c b/arch/openrisc/kernel/setup.c
index a9fb9cc6779e..000a9cc10e6f 100644
--- a/arch/openrisc/kernel/setup.c
+++ b/arch/openrisc/kernel/setup.c
@@ -249,6 +249,8 @@ void __init setup_arch(char **cmdline_p)
 		initrd_below_start_ok = 1;
 	}
 #endif
+	/* perform jump_table sorting before paging_init locks down read only memory */
+	jump_label_init();
 
 	/* paging_init() sets up the MMU and marks all pages as reserved */
 	paging_init();
-- 
2.45.2
Re: [PATCH v2 2/2] openrisc: Add jump label support
Posted by Stafford Horne 1 month, 3 weeks ago 
On Wed, Aug 06, 2025 at 02:05:04AM +0000, ChenMiao wrote:
> From: chenmiao <chenmiao.ku@gmail.com>
> 
> Implemented the full functionality of jump_label, of course,
> with text patching supported by just one API.
> 
> By the way, add new macro OPENRISC_INSN_NOP in insn-def.h to use.
> 
> - V2: using the patch_insn_write(void *addr, u32 insn) not the
> const void *insn.
> 
> Link: https://lore.kernel.org/openrisc/aJIC8o1WmVHol9RY@antec/T/#t
> 
> Signed-off-by: chenmiao <chenmiao.ku@gmail.com>
> ---
>  .../core/jump-labels/arch-support.txt         |  2 +-
>  arch/openrisc/Kconfig                         |  2 +
>  arch/openrisc/configs/or1ksim_defconfig       | 19 ++----
>  arch/openrisc/configs/virt_defconfig          |  1 +
>  arch/openrisc/include/asm/insn-def.h          |  3 +
>  arch/openrisc/include/asm/jump_label.h        | 68 +++++++++++++++++++
>  arch/openrisc/kernel/Makefile                 |  1 +
>  arch/openrisc/kernel/jump_label.c             | 53 +++++++++++++++
>  arch/openrisc/kernel/setup.c                  |  2 +
>  9 files changed, 138 insertions(+), 13 deletions(-)
>  create mode 100644 arch/openrisc/include/asm/jump_label.h
>  create mode 100644 arch/openrisc/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 ccada815569f..683de7c15058 100644
> --- a/Documentation/features/core/jump-labels/arch-support.txt
> +++ b/Documentation/features/core/jump-labels/arch-support.txt
> @@ -17,7 +17,7 @@
>      |  microblaze: | TODO |
>      |        mips: |  ok  |
>      |       nios2: | TODO |
> -    |    openrisc: | TODO |
> +    |    openrisc: |  ok  |
>      |      parisc: |  ok  |
>      |     powerpc: |  ok  |
>      |       riscv: |  ok  |
> diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
> index b38fee299bc4..9156635dd264 100644
> --- a/arch/openrisc/Kconfig
> +++ b/arch/openrisc/Kconfig
> @@ -24,6 +24,8 @@ config OPENRISC
>  	select GENERIC_PCI_IOMAP
>  	select GENERIC_IOREMAP
>  	select GENERIC_CPU_DEVICES
> +	select HAVE_ARCH_JUMP_LABEL
> +	select HAVE_ARCH_JUMP_LABEL_RELATIVE
>  	select HAVE_PCI
>  	select HAVE_UID16
>  	select HAVE_PAGE_SIZE_8KB
> diff --git a/arch/openrisc/configs/or1ksim_defconfig b/arch/openrisc/configs/or1ksim_defconfig
> index 59fe33cefba2..769705ac24d5 100644
> --- a/arch/openrisc/configs/or1ksim_defconfig
> +++ b/arch/openrisc/configs/or1ksim_defconfig
> @@ -3,26 +3,23 @@ CONFIG_LOG_BUF_SHIFT=14
>  CONFIG_BLK_DEV_INITRD=y
>  # CONFIG_RD_GZIP is not set
>  CONFIG_EXPERT=y
> -# CONFIG_KALLSYMS is not set
>  # CONFIG_EPOLL is not set
>  # CONFIG_TIMERFD is not set
>  # CONFIG_EVENTFD is not set
>  # CONFIG_AIO is not set
> -# CONFIG_VM_EVENT_COUNTERS is not set
> -# CONFIG_COMPAT_BRK is not set
> -CONFIG_SLUB=y
> -CONFIG_SLUB_TINY=y
> -CONFIG_MODULES=y
> -# CONFIG_BLOCK is not set
> +# CONFIG_KALLSYMS is not set
>  CONFIG_BUILTIN_DTB_NAME="or1ksim"
>  CONFIG_HZ_100=y
> +CONFIG_JUMP_LABEL=y
> +CONFIG_MODULES=y
> +# CONFIG_BLOCK is not set
> +CONFIG_SLUB_TINY=y
> +# CONFIG_COMPAT_BRK is not set
> +# CONFIG_VM_EVENT_COUNTERS is not set
>  CONFIG_NET=y
>  CONFIG_PACKET=y
>  CONFIG_UNIX=y
>  CONFIG_INET=y
> -# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
> -# CONFIG_INET_XFRM_MODE_TUNNEL is not set
> -# CONFIG_INET_XFRM_MODE_BEET is not set
>  # CONFIG_INET_DIAG is not set
>  CONFIG_TCP_CONG_ADVANCED=y
>  # CONFIG_TCP_CONG_BIC is not set
> @@ -35,7 +32,6 @@ CONFIG_DEVTMPFS=y
>  CONFIG_DEVTMPFS_MOUNT=y
>  # CONFIG_PREVENT_FIRMWARE_BUILD is not set
>  # CONFIG_FW_LOADER is not set
> -CONFIG_PROC_DEVICETREE=y
>  CONFIG_NETDEVICES=y
>  CONFIG_ETHOC=y
>  CONFIG_MICREL_PHY=y
> @@ -53,4 +49,3 @@ CONFIG_SERIAL_OF_PLATFORM=y
>  # CONFIG_DNOTIFY is not set
>  CONFIG_TMPFS=y
>  CONFIG_NFS_FS=y
> -# CONFIG_ENABLE_MUST_CHECK is not set
> diff --git a/arch/openrisc/configs/virt_defconfig b/arch/openrisc/configs/virt_defconfig
> index c1b69166c500..4a80c5794877 100644
> --- a/arch/openrisc/configs/virt_defconfig
> +++ b/arch/openrisc/configs/virt_defconfig
> @@ -12,6 +12,7 @@ CONFIG_NR_CPUS=8
>  CONFIG_SMP=y
>  CONFIG_HZ_100=y
>  # CONFIG_OPENRISC_NO_SPR_SR_DSX is not set
> +CONFIG_JUMP_LABEL=y
>  # CONFIG_COMPAT_BRK is not set
>  CONFIG_NET=y
>  CONFIG_PACKET=y

The defconfig updates look quite different.  Did you use savedefconfig for both
of them?

> diff --git a/arch/openrisc/include/asm/insn-def.h b/arch/openrisc/include/asm/insn-def.h
> index dc8d16db1579..2ccdbb37c27c 100644
> --- a/arch/openrisc/include/asm/insn-def.h
> +++ b/arch/openrisc/include/asm/insn-def.h
> @@ -9,4 +9,7 @@
>  /* or1k instructions are always 32 bits. */
>  #define	OPENRISC_INSN_SIZE		4
>  
> +/* or1k nop instruction code */
> +#define OPENRISC_INSN_NOP     0x15000000U

I see you use this header again here, note that in
arch/openrisc/kernel/signal.c.  We write instructions to memory too for the
sigreturn trampoline.

Also, you use OPENRISC_INSN_SIZE below.  Could you move this header to this
patch completely?  I don't think its needed in the patching patch.

>  #endif /* __ASM_INSN_DEF_H */
> diff --git a/arch/openrisc/include/asm/jump_label.h b/arch/openrisc/include/asm/jump_label.h
> new file mode 100644
> index 000000000000..03afca9c3a1f
> --- /dev/null
> +++ b/arch/openrisc/include/asm/jump_label.h
> @@ -0,0 +1,68 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2025 Chen Miao
> + *
> + * Based on arch/arm/include/asm/jump_label.h
> + */
> +#ifndef __ASM_JUMP_LABEL_H
> +#define __ASM_JUMP_LABEL_H

Can this be __ASM_OPENRISC_JUMP_LABEL_H?

> +#ifndef __ASSEMBLY__

Note upstream this is now __ASSEMBLER__.

> +#include <linux/types.h>
> +#include <asm/insn-def.h>
> +
> +#define HAVE_JUMP_LABEL_BATCH
> +
> +#define JUMP_LABEL_NOP_SIZE OPENRISC_INSN_SIZE
> +
> +/*
> + * should aligned 4
> + * for jump_label relative
> + * entry.code   = nop.addr - . -> return false
> + * entry.target = l_yes - .    -> return true
> + * entry.key	= key - .
> + */
> +#define JUMP_TABLE_ENTRY(key, label)			\
> +	".pushsection	__jump_table, \"aw\"	\n\t"	\
> +	".align 	4 			\n\t"	\
> +	".long 		1b - ., " label " - .	\n\t"	\
> +	".long 		" key " - . 		\n\t"	\
> +	".popsection				\n\t"
> +
> +#define ARCH_STATIC_BRANCH_ASM(key, label)		\
> +	".align		4			\n\t"	\
> +	"1: l.nop				\n\t"	\
> +	"    l.nop				\n\t"	\
> +	JUMP_TABLE_ENTRY(key, label)
> +
> +static __always_inline bool arch_static_branch(struct static_key *const key,
> +					       const bool branch)
> +{
> +	asm goto (ARCH_STATIC_BRANCH_ASM("%0", "%l[l_yes]")
> +		  ::"i"(&((char *)key)[branch])::l_yes);
> +
> +	return false;
> +l_yes:
> +	return true;
> +}
> +
> +#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label)		\
> +	".align		4			\n\t"	\
> +	"1: l.j	" label "			\n\t"	\
> +	"    l.nop				\n\t"	\
> +	JUMP_TABLE_ENTRY(key, label)
> +
> +static __always_inline bool
> +arch_static_branch_jump(struct static_key *const key, const bool branch)
> +{
> +	asm goto (ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[l_yes]")
> +		  ::"i"(&((char *)key)[branch])::l_yes);
> +
> +	return false;
> +l_yes:
> +	return true;
> +}
> +
> +#endif /* __ASSEMBLY__ */
> +#endif /* __ASM_JUMP_LABEL_H */
> diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
> index f0957ce16d6b..19e0eb94f2eb 100644
> --- a/arch/openrisc/kernel/Makefile
> +++ b/arch/openrisc/kernel/Makefile
> @@ -9,6 +9,7 @@ obj-y	:= head.o setup.o or32_ksyms.o process.o dma.o \
>  	   traps.o time.o irq.o entry.o ptrace.o signal.o \
>  	   sys_call_table.o unwinder.o cacheinfo.o
>  
> +obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
>  obj-$(CONFIG_SMP)		+= smp.o sync-timer.o
>  obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
>  obj-$(CONFIG_MODULES)		+= module.o
> diff --git a/arch/openrisc/kernel/jump_label.c b/arch/openrisc/kernel/jump_label.c
> new file mode 100644
> index 000000000000..ce259ba30258
> --- /dev/null
> +++ b/arch/openrisc/kernel/jump_label.c
> @@ -0,0 +1,53 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2025 Chen Miao
> + *
> + * Based on arch/arm/kernel/jump_label.c
> + */
> +#include <linux/jump_label.h>
> +#include <linux/kernel.h>
> +#include <linux/memory.h>
> +#include <asm/bug.h>
> +#include <asm/cacheflush.h>
> +#include <asm/text-patching.h>
> +
> +bool arch_jump_label_transform_queue(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;
> +
> +		offset = jump_entry_target(entry) - jump_entry_code(entry);
> +		/*
> +		 * The actual maximum range of the l.j instruction's offset is -134,217,728
> +		 * ~ 134,217,724 (sign 26-bit imm).
> +		 * For the original jump range, we need to right-shift N by 2 to obtain the
> +		 * instruction's offset.
> +		 */
> +		if (unlikely(offset < -134217728 || offset > 134217724)) {
> +			WARN_ON_ONCE(true);
> +		}
> +		/* 26bit imm mask */
> +		offset = (offset >> 2) & 0x03ffffff;
> +
> +		insn = offset;
> +	} else {
> +		insn = OPENRISC_INSN_NOP;
> +	}
> +
> +	if (early_boot_irqs_disabled) {
> +		copy_to_kernel_nofault(addr, &insn, sizeof(insn));
> +	} else {
> +		patch_insn_write(addr, insn);
> +	}
> +	return true;
> +}
> +
> +void arch_jump_label_transform_apply(void)
> +{
> +	// flush

Could you use the /* */ comment style?  Is this really flushing?

> +	kick_all_cpus_sync();
> +}
> diff --git a/arch/openrisc/kernel/setup.c b/arch/openrisc/kernel/setup.c
> index a9fb9cc6779e..000a9cc10e6f 100644
> --- a/arch/openrisc/kernel/setup.c
> +++ b/arch/openrisc/kernel/setup.c
> @@ -249,6 +249,8 @@ void __init setup_arch(char **cmdline_p)
>  		initrd_below_start_ok = 1;
>  	}
>  #endif
> +	/* perform jump_table sorting before paging_init locks down read only memory */
> +	jump_label_init();
>  
>  	/* paging_init() sets up the MMU and marks all pages as reserved */
>  	paging_init();
> -- 
> 2.45.2
>
Re: [PATCH v2 2/2] openrisc: Add jump label support
Posted by Miao Chen 1 month, 3 weeks ago 
Stafford Horne <shorne@gmail.com> 于2025年8月9日周六 16:37写道：
>
> On Wed, Aug 06, 2025 at 02:05:04AM +0000, ChenMiao wrote:
> > From: chenmiao <chenmiao.ku@gmail.com>
> >
> > Implemented the full functionality of jump_label, of course,
> > with text patching supported by just one API.
> >
> > By the way, add new macro OPENRISC_INSN_NOP in insn-def.h to use.
> >
> > - V2: using the patch_insn_write(void *addr, u32 insn) not the
> > const void *insn.
> >
> > Link: https://lore.kernel.org/openrisc/aJIC8o1WmVHol9RY@antec/T/#t
> >
> > Signed-off-by: chenmiao <chenmiao.ku@gmail.com>
> > ---
> >  .../core/jump-labels/arch-support.txt         |  2 +-
> >  arch/openrisc/Kconfig                         |  2 +
> >  arch/openrisc/configs/or1ksim_defconfig       | 19 ++----
> >  arch/openrisc/configs/virt_defconfig          |  1 +
> >  arch/openrisc/include/asm/insn-def.h          |  3 +
> >  arch/openrisc/include/asm/jump_label.h        | 68 +++++++++++++++++++
> >  arch/openrisc/kernel/Makefile                 |  1 +
> >  arch/openrisc/kernel/jump_label.c             | 53 +++++++++++++++
> >  arch/openrisc/kernel/setup.c                  |  2 +
> >  9 files changed, 138 insertions(+), 13 deletions(-)
> >  create mode 100644 arch/openrisc/include/asm/jump_label.h
> >  create mode 100644 arch/openrisc/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 ccada815569f..683de7c15058 100644
> > --- a/Documentation/features/core/jump-labels/arch-support.txt
> > +++ b/Documentation/features/core/jump-labels/arch-support.txt
> > @@ -17,7 +17,7 @@
> >      |  microblaze: | TODO |
> >      |        mips: |  ok  |
> >      |       nios2: | TODO |
> > -    |    openrisc: | TODO |
> > +    |    openrisc: |  ok  |
> >      |      parisc: |  ok  |
> >      |     powerpc: |  ok  |
> >      |       riscv: |  ok  |
> > diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
> > index b38fee299bc4..9156635dd264 100644
> > --- a/arch/openrisc/Kconfig
> > +++ b/arch/openrisc/Kconfig
> > @@ -24,6 +24,8 @@ config OPENRISC
> >       select GENERIC_PCI_IOMAP
> >       select GENERIC_IOREMAP
> >       select GENERIC_CPU_DEVICES
> > +     select HAVE_ARCH_JUMP_LABEL
> > +     select HAVE_ARCH_JUMP_LABEL_RELATIVE
> >       select HAVE_PCI
> >       select HAVE_UID16
> >       select HAVE_PAGE_SIZE_8KB
> > diff --git a/arch/openrisc/configs/or1ksim_defconfig b/arch/openrisc/configs/or1ksim_defconfig
> > index 59fe33cefba2..769705ac24d5 100644
> > --- a/arch/openrisc/configs/or1ksim_defconfig
> > +++ b/arch/openrisc/configs/or1ksim_defconfig
> > @@ -3,26 +3,23 @@ CONFIG_LOG_BUF_SHIFT=14
> >  CONFIG_BLK_DEV_INITRD=y
> >  # CONFIG_RD_GZIP is not set
> >  CONFIG_EXPERT=y
> > -# CONFIG_KALLSYMS is not set
> >  # CONFIG_EPOLL is not set
> >  # CONFIG_TIMERFD is not set
> >  # CONFIG_EVENTFD is not set
> >  # CONFIG_AIO is not set
> > -# CONFIG_VM_EVENT_COUNTERS is not set
> > -# CONFIG_COMPAT_BRK is not set
> > -CONFIG_SLUB=y
> > -CONFIG_SLUB_TINY=y
> > -CONFIG_MODULES=y
> > -# CONFIG_BLOCK is not set
> > +# CONFIG_KALLSYMS is not set
> >  CONFIG_BUILTIN_DTB_NAME="or1ksim"
> >  CONFIG_HZ_100=y
> > +CONFIG_JUMP_LABEL=y
> > +CONFIG_MODULES=y
> > +# CONFIG_BLOCK is not set
> > +CONFIG_SLUB_TINY=y
> > +# CONFIG_COMPAT_BRK is not set
> > +# CONFIG_VM_EVENT_COUNTERS is not set
> >  CONFIG_NET=y
> >  CONFIG_PACKET=y
> >  CONFIG_UNIX=y
> >  CONFIG_INET=y
> > -# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
> > -# CONFIG_INET_XFRM_MODE_TUNNEL is not set
> > -# CONFIG_INET_XFRM_MODE_BEET is not set
> >  # CONFIG_INET_DIAG is not set
> >  CONFIG_TCP_CONG_ADVANCED=y
> >  # CONFIG_TCP_CONG_BIC is not set
> > @@ -35,7 +32,6 @@ CONFIG_DEVTMPFS=y
> >  CONFIG_DEVTMPFS_MOUNT=y
> >  # CONFIG_PREVENT_FIRMWARE_BUILD is not set
> >  # CONFIG_FW_LOADER is not set
> > -CONFIG_PROC_DEVICETREE=y
> >  CONFIG_NETDEVICES=y
> >  CONFIG_ETHOC=y
> >  CONFIG_MICREL_PHY=y
> > @@ -53,4 +49,3 @@ CONFIG_SERIAL_OF_PLATFORM=y
> >  # CONFIG_DNOTIFY is not set
> >  CONFIG_TMPFS=y
> >  CONFIG_NFS_FS=y
> > -# CONFIG_ENABLE_MUST_CHECK is not set
> > diff --git a/arch/openrisc/configs/virt_defconfig b/arch/openrisc/configs/virt_defconfig
> > index c1b69166c500..4a80c5794877 100644
> > --- a/arch/openrisc/configs/virt_defconfig
> > +++ b/arch/openrisc/configs/virt_defconfig
> > @@ -12,6 +12,7 @@ CONFIG_NR_CPUS=8
> >  CONFIG_SMP=y
> >  CONFIG_HZ_100=y
> >  # CONFIG_OPENRISC_NO_SPR_SR_DSX is not set
> > +CONFIG_JUMP_LABEL=y
> >  # CONFIG_COMPAT_BRK is not set
> >  CONFIG_NET=y
> >  CONFIG_PACKET=y
>
> The defconfig updates look quite different.  Did you use savedefconfig for both
> of them?

Sure, it will do in the next version.

>
> > diff --git a/arch/openrisc/include/asm/insn-def.h b/arch/openrisc/include/asm/insn-def.h
> > index dc8d16db1579..2ccdbb37c27c 100644
> > --- a/arch/openrisc/include/asm/insn-def.h
> > +++ b/arch/openrisc/include/asm/insn-def.h
> > @@ -9,4 +9,7 @@
> >  /* or1k instructions are always 32 bits. */
> >  #define      OPENRISC_INSN_SIZE              4
> >
> > +/* or1k nop instruction code */
> > +#define OPENRISC_INSN_NOP     0x15000000U
>
> I see you use this header again here, note that in
> arch/openrisc/kernel/signal.c.  We write instructions to memory too for the
> sigreturn trampoline.
>
> Also, you use OPENRISC_INSN_SIZE below.  Could you move this header to this
> patch completely?  I don't think its needed in the patching patch.
>

maybe... this patch we no need this header, but I think this header is
meaningful, we can do this in another patch? modify the hard code insn
to macro.

> >  #endif /* __ASM_INSN_DEF_H */
> > diff --git a/arch/openrisc/include/asm/jump_label.h b/arch/openrisc/include/asm/jump_label.h
> > new file mode 100644
> > index 000000000000..03afca9c3a1f
> > --- /dev/null
> > +++ b/arch/openrisc/include/asm/jump_label.h
> > @@ -0,0 +1,68 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright (C) 2025 Chen Miao
> > + *
> > + * Based on arch/arm/include/asm/jump_label.h
> > + */
> > +#ifndef __ASM_JUMP_LABEL_H
> > +#define __ASM_JUMP_LABEL_H
>
> Can this be __ASM_OPENRISC_JUMP_LABEL_H?
>
> > +#ifndef __ASSEMBLY__
>
> Note upstream this is now __ASSEMBLER__.

copy that.

>
> > +#include <linux/types.h>
> > +#include <asm/insn-def.h>
> > +
> > +#define HAVE_JUMP_LABEL_BATCH
> > +
> > +#define JUMP_LABEL_NOP_SIZE OPENRISC_INSN_SIZE
> > +
> > +/*
> > + * should aligned 4
> > + * for jump_label relative
> > + * entry.code   = nop.addr - . -> return false
> > + * entry.target = l_yes - .    -> return true
> > + * entry.key = key - .
> > + */
> > +#define JUMP_TABLE_ENTRY(key, label)                 \
> > +     ".pushsection   __jump_table, \"aw\"    \n\t"   \
> > +     ".align         4                       \n\t"   \
> > +     ".long          1b - ., " label " - .   \n\t"   \
> > +     ".long          " key " - .             \n\t"   \
> > +     ".popsection                            \n\t"
> > +
> > +#define ARCH_STATIC_BRANCH_ASM(key, label)           \
> > +     ".align         4                       \n\t"   \
> > +     "1: l.nop                               \n\t"   \
> > +     "    l.nop                              \n\t"   \
> > +     JUMP_TABLE_ENTRY(key, label)
> > +
> > +static __always_inline bool arch_static_branch(struct static_key *const key,
> > +                                            const bool branch)
> > +{
> > +     asm goto (ARCH_STATIC_BRANCH_ASM("%0", "%l[l_yes]")
> > +               ::"i"(&((char *)key)[branch])::l_yes);
> > +
> > +     return false;
> > +l_yes:
> > +     return true;
> > +}
> > +
> > +#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label)              \
> > +     ".align         4                       \n\t"   \
> > +     "1: l.j " label "                       \n\t"   \
> > +     "    l.nop                              \n\t"   \
> > +     JUMP_TABLE_ENTRY(key, label)
> > +
> > +static __always_inline bool
> > +arch_static_branch_jump(struct static_key *const key, const bool branch)
> > +{
> > +     asm goto (ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[l_yes]")
> > +               ::"i"(&((char *)key)[branch])::l_yes);
> > +
> > +     return false;
> > +l_yes:
> > +     return true;
> > +}
> > +
> > +#endif /* __ASSEMBLY__ */
> > +#endif /* __ASM_JUMP_LABEL_H */
> > diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
> > index f0957ce16d6b..19e0eb94f2eb 100644
> > --- a/arch/openrisc/kernel/Makefile
> > +++ b/arch/openrisc/kernel/Makefile
> > @@ -9,6 +9,7 @@ obj-y := head.o setup.o or32_ksyms.o process.o dma.o \
> >          traps.o time.o irq.o entry.o ptrace.o signal.o \
> >          sys_call_table.o unwinder.o cacheinfo.o
> >
> > +obj-$(CONFIG_JUMP_LABEL)     += jump_label.o
> >  obj-$(CONFIG_SMP)            += smp.o sync-timer.o
> >  obj-$(CONFIG_STACKTRACE)     += stacktrace.o
> >  obj-$(CONFIG_MODULES)                += module.o
> > diff --git a/arch/openrisc/kernel/jump_label.c b/arch/openrisc/kernel/jump_label.c
> > new file mode 100644
> > index 000000000000..ce259ba30258
> > --- /dev/null
> > +++ b/arch/openrisc/kernel/jump_label.c
> > @@ -0,0 +1,53 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Copyright (C) 2025 Chen Miao
> > + *
> > + * Based on arch/arm/kernel/jump_label.c
> > + */
> > +#include <linux/jump_label.h>
> > +#include <linux/kernel.h>
> > +#include <linux/memory.h>
> > +#include <asm/bug.h>
> > +#include <asm/cacheflush.h>
> > +#include <asm/text-patching.h>
> > +
> > +bool arch_jump_label_transform_queue(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;
> > +
> > +             offset = jump_entry_target(entry) - jump_entry_code(entry);
> > +             /*
> > +              * The actual maximum range of the l.j instruction's offset is -134,217,728
> > +              * ~ 134,217,724 (sign 26-bit imm).
> > +              * For the original jump range, we need to right-shift N by 2 to obtain the
> > +              * instruction's offset.
> > +              */
> > +             if (unlikely(offset < -134217728 || offset > 134217724)) {
> > +                     WARN_ON_ONCE(true);
> > +             }
> > +             /* 26bit imm mask */
> > +             offset = (offset >> 2) & 0x03ffffff;
> > +
> > +             insn = offset;
> > +     } else {
> > +             insn = OPENRISC_INSN_NOP;
> > +     }
> > +
> > +     if (early_boot_irqs_disabled) {
> > +             copy_to_kernel_nofault(addr, &insn, sizeof(insn));
> > +     } else {
> > +             patch_insn_write(addr, insn);
> > +     }
> > +     return true;
> > +}
> > +
> > +void arch_jump_label_transform_apply(void)
> > +{
> > +     // flush
>
> Could you use the /* */ comment style?  Is this really flushing?

sure, really flushing.

>
> > +     kick_all_cpus_sync();
> > +}
> > diff --git a/arch/openrisc/kernel/setup.c b/arch/openrisc/kernel/setup.c
> > index a9fb9cc6779e..000a9cc10e6f 100644
> > --- a/arch/openrisc/kernel/setup.c
> > +++ b/arch/openrisc/kernel/setup.c
> > @@ -249,6 +249,8 @@ void __init setup_arch(char **cmdline_p)
> >               initrd_below_start_ok = 1;
> >       }
> >  #endif
> > +     /* perform jump_table sorting before paging_init locks down read only memory */
> > +     jump_label_init();
> >
> >       /* paging_init() sets up the MMU and marks all pages as reserved */
> >       paging_init();
> > --
> > 2.45.2
> >

Patchew 2.1-devel-b67e4c2

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