diff options
Diffstat (limited to 'arch/x86/include/asm/jump_label.h')
| -rw-r--r-- | arch/x86/include/asm/jump_label.h | 113 |
1 files changed, 31 insertions, 82 deletions
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h index adc54c12cbd1..05b16299588d 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -1,43 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_JUMP_LABEL_H #define _ASM_X86_JUMP_LABEL_H -#ifndef HAVE_JUMP_LABEL -/* - * For better or for worse, if jump labels (the gcc extension) are missing, - * then the entire static branch patching infrastructure is compiled out. - * If that happens, the code in here will malfunction. Raise a compiler - * error instead. - * - * In theory, jump labels and the static branch patching infrastructure - * could be decoupled to fix this. - */ -#error asm/jump_label.h included on a non-jump-label kernel -#endif - -#define JUMP_LABEL_NOP_SIZE 5 - -#ifdef CONFIG_X86_64 -# define STATIC_KEY_INIT_NOP P6_NOP5_ATOMIC -#else -# define STATIC_KEY_INIT_NOP GENERIC_NOP5_ATOMIC -#endif +#define HAVE_JUMP_LABEL_BATCH #include <asm/asm.h> #include <asm/nops.h> -#ifndef __ASSEMBLY__ +#ifndef __ASSEMBLER__ #include <linux/stringify.h> #include <linux/types.h> -static __always_inline bool arch_static_branch(struct static_key *key, bool branch) +#define JUMP_TABLE_ENTRY(key, label) \ + ".pushsection __jump_table, \"aw\" \n\t" \ + _ASM_ALIGN "\n\t" \ + ANNOTATE_DATA_SPECIAL "\n" \ + ".long 1b - . \n\t" \ + ".long " label " - . \n\t" \ + _ASM_PTR " " key " - . \n\t" \ + ".popsection \n\t" + +/* This macro is also expanded on the Rust side. */ +#ifdef CONFIG_HAVE_JUMP_LABEL_HACK +#define ARCH_STATIC_BRANCH_ASM(key, label) \ + "1: jmp " label " # objtool NOPs this \n\t" \ + JUMP_TABLE_ENTRY(key " + 2", label) +#else /* !CONFIG_HAVE_JUMP_LABEL_HACK */ +#define ARCH_STATIC_BRANCH_ASM(key, label) \ + "1: .byte " __stringify(BYTES_NOP5) "\n\t" \ + JUMP_TABLE_ENTRY(key, label) +#endif /* CONFIG_HAVE_JUMP_LABEL_HACK */ + +static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch) { - asm_volatile_goto("1:" - ".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t" - ".pushsection __jump_table, \"aw\" \n\t" - _ASM_ALIGN "\n\t" - _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t" - ".popsection \n\t" + asm goto(ARCH_STATIC_BRANCH_ASM("%c0 + %c1", "%l[l_yes]") : : "i" (key), "i" (branch) : : l_yes); return false; @@ -45,15 +42,11 @@ l_yes: return true; } -static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch) +static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch) { - asm_volatile_goto("1:" - ".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t" - "2:\n\t" - ".pushsection __jump_table, \"aw\" \n\t" - _ASM_ALIGN "\n\t" - _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t" - ".popsection \n\t" + asm goto("1:" + "jmp %l[l_yes]\n\t" + JUMP_TABLE_ENTRY("%c0 + %c1", "%l[l_yes]") : : "i" (key), "i" (branch) : : l_yes); return false; @@ -61,52 +54,8 @@ l_yes: return true; } -#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; -}; - -#else /* __ASSEMBLY__ */ - -.macro STATIC_JUMP_IF_TRUE target, key, def -.Lstatic_jump_\@: - .if \def - /* Equivalent to "jmp.d32 \target" */ - .byte 0xe9 - .long \target - .Lstatic_jump_after_\@ -.Lstatic_jump_after_\@: - .else - .byte STATIC_KEY_INIT_NOP - .endif - .pushsection __jump_table, "aw" - _ASM_ALIGN - _ASM_PTR .Lstatic_jump_\@, \target, \key - .popsection -.endm - -.macro STATIC_JUMP_IF_FALSE target, key, def -.Lstatic_jump_\@: - .if \def - .byte STATIC_KEY_INIT_NOP - .else - /* Equivalent to "jmp.d32 \target" */ - .byte 0xe9 - .long \target - .Lstatic_jump_after_\@ -.Lstatic_jump_after_\@: - .endif - .pushsection __jump_table, "aw" - _ASM_ALIGN - _ASM_PTR .Lstatic_jump_\@, \target, \key + 1 - .popsection -.endm +extern int arch_jump_entry_size(struct jump_entry *entry); -#endif /* __ASSEMBLY__ */ +#endif /* __ASSEMBLER__ */ #endif |