diff options
Diffstat (limited to 'arch/x86/include/asm/jump_label.h')
-rw-r--r-- | arch/x86/include/asm/jump_label.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h new file mode 100644 index 00000000..3a16c148 --- /dev/null +++ b/arch/x86/include/asm/jump_label.h @@ -0,0 +1,42 @@ +#ifndef _ASM_X86_JUMP_LABEL_H +#define _ASM_X86_JUMP_LABEL_H + +#ifdef __KERNEL__ + +#include <linux/types.h> +#include <asm/nops.h> +#include <asm/asm.h> + +#define JUMP_LABEL_NOP_SIZE 5 + +#define STATIC_KEY_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t" + +static __always_inline bool arch_static_branch(struct static_key *key) +{ + asm goto("1:" + STATIC_KEY_INITIAL_NOP + ".pushsection __jump_table, \"aw\" \n\t" + _ASM_ALIGN "\n\t" + _ASM_PTR "1b, %l[l_yes], %c0 \n\t" + ".popsection \n\t" + : : "i" (key) : : l_yes); + return false; +l_yes: + return true; +} + +#endif /* __KERNEL__ */ + +#ifdef CONFIG_X86_64 +typedef u64 jump_label_t; +#else +typedef u32 jump_label_t; +#endif + +struct jump_entry { + jump_label_t code; + jump_label_t target; + jump_label_t key; +}; + +#endif |