diff options
Diffstat (limited to 'arch/x86/kernel/jump_label.c')
-rw-r--r-- | arch/x86/kernel/jump_label.c | 81 |
1 files changed, 52 insertions, 29 deletions
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index 6a2eb62c85e6..674906fad43b 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -15,50 +15,75 @@ #include <asm/kprobes.h> #include <asm/alternative.h> #include <asm/text-patching.h> +#include <asm/insn.h> -static void bug_at(const void *ip, int line) +int arch_jump_entry_size(struct jump_entry *entry) { - /* - * The location is not an op that we were expecting. - * Something went wrong. Crash the box, as something could be - * corrupting the kernel. - */ - pr_crit("jump_label: Fatal kernel bug, unexpected op at %pS [%p] (%5ph) %d\n", ip, ip, ip, line); - BUG(); + struct insn insn = {}; + + insn_decode_kernel(&insn, (void *)jump_entry_code(entry)); + BUG_ON(insn.length != 2 && insn.length != 5); + + return insn.length; } -static const void * -__jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type) +struct jump_label_patch { + const void *code; + int size; +}; + +static struct jump_label_patch +__jump_label_patch(struct jump_entry *entry, enum jump_label_type type) { - const void *expect, *code; + const void *expect, *code, *nop; const void *addr, *dest; - int line; + int size; addr = (void *)jump_entry_code(entry); dest = (void *)jump_entry_target(entry); - code = text_gen_insn(JMP32_INSN_OPCODE, addr, dest); + size = arch_jump_entry_size(entry); + switch (size) { + case JMP8_INSN_SIZE: + code = text_gen_insn(JMP8_INSN_OPCODE, addr, dest); + nop = x86_nops[size]; + break; - if (type == JUMP_LABEL_JMP) { - expect = x86_nops[5]; line = __LINE__; - } else { - expect = code; line = __LINE__; + case JMP32_INSN_SIZE: + code = text_gen_insn(JMP32_INSN_OPCODE, addr, dest); + nop = x86_nops[size]; + break; + + default: BUG(); } - if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE)) - bug_at(addr, line); + if (type == JUMP_LABEL_JMP) + expect = nop; + else + expect = code; + + if (memcmp(addr, expect, size)) { + /* + * The location is not an op that we were expecting. + * Something went wrong. Crash the box, as something could be + * corrupting the kernel. + */ + pr_crit("jump_label: Fatal kernel bug, unexpected op at %pS [%p] (%5ph != %5ph)) size:%d type:%d\n", + addr, addr, addr, expect, size, type); + BUG(); + } if (type == JUMP_LABEL_NOP) - code = x86_nops[5]; + code = nop; - return code; + return (struct jump_label_patch){.code = code, .size = size}; } static inline void __jump_label_transform(struct jump_entry *entry, enum jump_label_type type, int init) { - const void *opcode = __jump_label_set_jump_code(entry, type); + const struct jump_label_patch jlp = __jump_label_patch(entry, type); /* * As long as only a single processor is running and the code is still @@ -72,12 +97,11 @@ static inline void __jump_label_transform(struct jump_entry *entry, * always nop being the 'currently valid' instruction */ if (init || system_state == SYSTEM_BOOTING) { - text_poke_early((void *)jump_entry_code(entry), opcode, - JUMP_LABEL_NOP_SIZE); + text_poke_early((void *)jump_entry_code(entry), jlp.code, jlp.size); return; } - text_poke_bp((void *)jump_entry_code(entry), opcode, JUMP_LABEL_NOP_SIZE, NULL); + text_poke_bp((void *)jump_entry_code(entry), jlp.code, jlp.size, NULL); } static void __ref jump_label_transform(struct jump_entry *entry, @@ -98,7 +122,7 @@ void arch_jump_label_transform(struct jump_entry *entry, bool arch_jump_label_transform_queue(struct jump_entry *entry, enum jump_label_type type) { - const void *opcode; + struct jump_label_patch jlp; if (system_state == SYSTEM_BOOTING) { /* @@ -109,9 +133,8 @@ bool arch_jump_label_transform_queue(struct jump_entry *entry, } mutex_lock(&text_mutex); - opcode = __jump_label_set_jump_code(entry, type); - text_poke_queue((void *)jump_entry_code(entry), - opcode, JUMP_LABEL_NOP_SIZE, NULL); + jlp = __jump_label_patch(entry, type); + text_poke_queue((void *)jump_entry_code(entry), jlp.code, jlp.size, NULL); mutex_unlock(&text_mutex); return true; } |