diff options
| -rw-r--r-- | arch/arm/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm/include/asm/jump_label.h | 41 | ||||
| -rw-r--r-- | arch/arm/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/kernel/insn.h | 10 | ||||
| -rw-r--r-- | arch/arm/kernel/jump_label.c | 39 |
5 files changed, 92 insertions, 0 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 6b5f84887ce5..ee6c7154c9a1 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -9,6 +9,7 @@ config ARM select SYS_SUPPORTS_APM_EMULATION select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI) select HAVE_OPROFILE if (HAVE_PERF_EVENTS) + select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL select HAVE_ARCH_KGDB select HAVE_KPROBES if !XIP_KERNEL select HAVE_KRETPROBES if (HAVE_KPROBES) diff --git a/arch/arm/include/asm/jump_label.h b/arch/arm/include/asm/jump_label.h new file mode 100644 index 000000000000..5c5ca2ea62b0 --- /dev/null +++ b/arch/arm/include/asm/jump_label.h @@ -0,0 +1,41 @@ +#ifndef _ASM_ARM_JUMP_LABEL_H +#define _ASM_ARM_JUMP_LABEL_H + +#ifdef __KERNEL__ + +#include <linux/types.h> +#include <asm/system.h> + +#define JUMP_LABEL_NOP_SIZE 4 + +#ifdef CONFIG_THUMB2_KERNEL +#define JUMP_LABEL_NOP "nop.w" +#else +#define JUMP_LABEL_NOP "nop" +#endif + +static __always_inline bool arch_static_branch(struct jump_label_key *key) +{ + asm goto("1:\n\t" + JUMP_LABEL_NOP "\n\t" + ".pushsection __jump_table, \"aw\"\n\t" + ".word 1b, %l[l_yes], %c0\n\t" + ".popsection\n\t" + : : "i" (key) : : l_yes); + + return false; +l_yes: + return true; +} + +#endif /* __KERNEL__ */ + +typedef u32 jump_label_t; + +struct jump_entry { + jump_label_t code; + jump_label_t target; + jump_label_t key; +}; + +#endif diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 8c63ee8d3c48..1b7d9a390971 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -38,6 +38,7 @@ obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o +obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o patch.o ifdef CONFIG_THUMB2_KERNEL diff --git a/arch/arm/kernel/insn.h b/arch/arm/kernel/insn.h index 994d60fd3ff5..e96065da4dae 100644 --- a/arch/arm/kernel/insn.h +++ b/arch/arm/kernel/insn.h @@ -1,6 +1,16 @@ #ifndef __ASM_ARM_INSN_H #define __ASM_ARM_INSN_H +static inline unsigned long +arm_gen_nop(void) +{ +#ifdef CONFIG_THUMB2_KERNEL + return 0xf3af8000; /* nop.w */ +#else + return 0xe1a00000; /* mov r0, r0 */ +#endif +} + unsigned long __arm_gen_branch(unsigned long pc, unsigned long addr, bool link); diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c new file mode 100644 index 000000000000..4ce4f789446d --- /dev/null +++ b/arch/arm/kernel/jump_label.c @@ -0,0 +1,39 @@ +#include <linux/kernel.h> +#include <linux/jump_label.h> + +#include "insn.h" +#include "patch.h" + +#ifdef HAVE_JUMP_LABEL + +static void __arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type, + bool is_static) +{ + void *addr = (void *)entry->code; + unsigned int insn; + + if (type == JUMP_LABEL_ENABLE) + insn = arm_gen_branch(entry->code, entry->target); + else + insn = arm_gen_nop(); + + if (is_static) + __patch_text(addr, insn); + else + patch_text(addr, insn); +} + +void arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ + __arch_jump_label_transform(entry, type, false); +} + +void arch_jump_label_transform_static(struct jump_entry *entry, + enum jump_label_type type) +{ + __arch_jump_label_transform(entry, type, true); +} + +#endif |