diff options
| -rw-r--r-- | arch/x86/include/asm/text-patching.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/alternative.c | 36 | ||||
| -rw-r--r-- | arch/x86/kernel/jump_label.c | 31 | ||||
| -rw-r--r-- | arch/x86/kernel/kprobes/opt.c | 7 |
4 files changed, 50 insertions, 26 deletions
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index 3bcd26623a1f..95beb85aef65 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -49,6 +49,8 @@ extern void text_poke_bp(void *addr, const void *opcode, size_t len, const void extern void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate); extern void text_poke_finish(void); +extern void *text_gen_insn(u8 opcode, const void *addr, const void *dest); + extern int after_bootmem; extern __ro_after_init struct mm_struct *poking_mm; extern __ro_after_init unsigned long poking_addr; diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 42e7f0af88da..714b4a2a6f81 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1237,3 +1237,39 @@ void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulat text_poke_loc_init(&tp, addr, opcode, len, emulate); text_poke_bp_batch(&tp, 1); } + +union text_poke_insn { + u8 text[POKE_MAX_OPCODE_SIZE]; + struct { + u8 opcode; + s32 disp; + } __attribute__((packed)); +}; + +void *text_gen_insn(u8 opcode, const void *addr, const void *dest) +{ + static union text_poke_insn insn; /* text_mutex */ + int size = 0; + + lockdep_assert_held(&text_mutex); + + insn.opcode = opcode; + +#define __CASE(insn) \ + case insn##_INSN_OPCODE: size = insn##_INSN_SIZE; break + + switch(opcode) { + __CASE(INT3); + __CASE(CALL); + __CASE(JMP32); + __CASE(JMP8); + } + + if (size > 1) { + insn.disp = (long)dest - (long)(addr + size); + if (size == 2) + BUG_ON((insn.disp >> 31) != (insn.disp >> 7)); + } + + return &insn.text; +} diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index cf8c847c7b5d..9c4498ea0b3c 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -16,15 +16,7 @@ #include <asm/alternative.h> #include <asm/text-patching.h> -union jump_code_union { - char code[JUMP_LABEL_NOP_SIZE]; - struct { - char jump; - int offset; - } __attribute__((packed)); -}; - -static void bug_at(unsigned char *ip, int line) +static void bug_at(const void *ip, int line) { /* * The location is not an op that we were expecting. @@ -38,33 +30,32 @@ static void bug_at(unsigned char *ip, int line) static const void * __jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type, int init) { - static union jump_code_union code; /* relies on text_mutex */ const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; - const void *expect; + const void *expect, *code; + const void *addr, *dest; int line; - lockdep_assert_held(&text_mutex); + addr = (void *)jump_entry_code(entry); + dest = (void *)jump_entry_target(entry); - code.jump = JMP32_INSN_OPCODE; - code.offset = jump_entry_target(entry) - - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); + code = text_gen_insn(JMP32_INSN_OPCODE, addr, dest); if (init) { expect = default_nop; line = __LINE__; } else if (type == JUMP_LABEL_JMP) { expect = ideal_nop; line = __LINE__; } else { - expect = code.code; line = __LINE__; + expect = code; line = __LINE__; } - if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE)) - bug_at((void *)jump_entry_code(entry), line); + if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE)) + bug_at(addr, line); if (type == JUMP_LABEL_NOP) - memcpy(&code, ideal_nop, JUMP_LABEL_NOP_SIZE); + code = ideal_nop; - return &code; + return code; } static void inline __jump_label_transform(struct jump_entry *entry, diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 8900329c28a7..9b01ee7b3923 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -447,18 +447,13 @@ void arch_optimize_kprobes(struct list_head *oplist) void arch_unoptimize_kprobe(struct optimized_kprobe *op) { u8 insn_buff[RELATIVEJUMP_SIZE]; - u8 emulate_buff[RELATIVEJUMP_SIZE]; /* Set int3 to first byte for kprobes */ insn_buff[0] = BREAKPOINT_INSTRUCTION; memcpy(insn_buff + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE); - emulate_buff[0] = RELATIVEJUMP_OPCODE; - *(s32 *)(&emulate_buff[1]) = (s32)((long)op->optinsn.insn - - ((long)op->kp.addr + RELATIVEJUMP_SIZE)); - text_poke_bp(op->kp.addr, insn_buff, RELATIVEJUMP_SIZE, - emulate_buff); + text_gen_insn(JMP32_INSN_OPCODE, op->kp.addr, op->optinsn.insn)); } /* |