diff options
Diffstat (limited to 'arch/x86/kernel/kprobes/core.c')
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 596 |
1 files changed, 382 insertions, 214 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index df776cdca327..d3d65545cb8b 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -139,6 +139,8 @@ NOKPROBE_SYMBOL(synthesize_relcall); int can_boost(struct insn *insn, void *addr) { kprobe_opcode_t opcode; + insn_byte_t prefix; + int i; if (search_exception_tables((unsigned long)addr)) return 0; /* Page fault may occur on this address. */ @@ -151,35 +153,39 @@ int can_boost(struct insn *insn, void *addr) if (insn->opcode.nbytes != 1) return 0; - /* Can't boost Address-size override prefix */ - if (unlikely(inat_is_address_size_prefix(insn->attr))) - return 0; + for_each_insn_prefix(insn, i, prefix) { + insn_attr_t attr; + + attr = inat_get_opcode_attribute(prefix); + /* Can't boost Address-size override prefix and CS override prefix */ + if (prefix == 0x2e || inat_is_address_size_prefix(attr)) + return 0; + } opcode = insn->opcode.bytes[0]; - switch (opcode & 0xf0) { - case 0x60: - /* can't boost "bound" */ - return (opcode != 0x62); - case 0x70: - return 0; /* can't boost conditional jump */ - case 0x90: - return opcode != 0x9a; /* can't boost call far */ - case 0xc0: - /* can't boost software-interruptions */ - return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf; - case 0xd0: - /* can boost AA* and XLAT */ - return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7); - case 0xe0: - /* can boost in/out and absolute jmps */ - return ((opcode & 0x04) || opcode == 0xea); - case 0xf0: - /* clear and set flags are boostable */ - return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe)); + switch (opcode) { + case 0x62: /* bound */ + case 0x70 ... 0x7f: /* Conditional jumps */ + case 0x9a: /* Call far */ + case 0xc0 ... 0xc1: /* Grp2 */ + case 0xcc ... 0xce: /* software exceptions */ + case 0xd0 ... 0xd3: /* Grp2 */ + case 0xd6: /* (UD) */ + case 0xd8 ... 0xdf: /* ESC */ + case 0xe0 ... 0xe3: /* LOOP*, JCXZ */ + case 0xe8 ... 0xe9: /* near Call, JMP */ + case 0xeb: /* Short JMP */ + case 0xf0 ... 0xf4: /* LOCK/REP, HLT */ + case 0xf6 ... 0xf7: /* Grp3 */ + case 0xfe: /* Grp4 */ + /* ... are not boostable */ + return 0; + case 0xff: /* Grp5 */ + /* Only indirect jmp is boostable */ + return X86_MODRM_REG(insn->modrm.bytes[0]) == 4; default: - /* CS override prefix and call are not boostable */ - return (opcode != 0x2e && opcode != 0x9a); + return 1; } } @@ -229,7 +235,7 @@ __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) return 0UL; if (faddr) - memcpy(buf, ideal_nops[NOP_ATOMIC5], 5); + memcpy(buf, x86_nops[5], 5); else buf[0] = kp->opcode; return (unsigned long)buf; @@ -265,6 +271,8 @@ static int can_probe(unsigned long paddr) /* Decode instructions */ addr = paddr - offset; while (addr < paddr) { + int ret; + /* * Check if the instruction has been modified by another * kprobe, in which case we replace the breakpoint by the @@ -276,8 +284,10 @@ static int can_probe(unsigned long paddr) __addr = recover_probed_instruction(buf, addr); if (!__addr) return 0; - kernel_insn_init(&insn, (void *)__addr, MAX_INSN_SIZE); - insn_get_length(&insn); + + ret = insn_decode_kernel(&insn, (void *)__addr); + if (ret < 0) + return 0; /* * Another debugging subsystem might insert this breakpoint. @@ -301,8 +311,8 @@ static int can_probe(unsigned long paddr) int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) { kprobe_opcode_t buf[MAX_INSN_SIZE]; - unsigned long recovered_insn = - recover_probed_instruction(buf, (unsigned long)src); + unsigned long recovered_insn = recover_probed_instruction(buf, (unsigned long)src); + int ret; if (!recovered_insn || !insn) return 0; @@ -312,8 +322,9 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) MAX_INSN_SIZE)) return 0; - kernel_insn_init(insn, dest, MAX_INSN_SIZE); - insn_get_length(insn); + ret = insn_decode_kernel(insn, dest); + if (ret < 0) + return 0; /* We can not probe force emulate prefixed instruction */ if (insn_has_emulate_prefix(insn)) @@ -357,13 +368,14 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) return insn->length; } -/* Prepare reljump right after instruction to boost */ -static int prepare_boost(kprobe_opcode_t *buf, struct kprobe *p, - struct insn *insn) +/* Prepare reljump or int3 right after instruction */ +static int prepare_singlestep(kprobe_opcode_t *buf, struct kprobe *p, + struct insn *insn) { int len = insn->length; - if (can_boost(insn, p->addr) && + if (!IS_ENABLED(CONFIG_PREEMPTION) && + !p->post_handler && can_boost(insn, p->addr) && MAX_INSN_SIZE - len >= JMP32_INSN_SIZE) { /* * These instructions can be executed directly if it @@ -374,7 +386,12 @@ static int prepare_boost(kprobe_opcode_t *buf, struct kprobe *p, len += JMP32_INSN_SIZE; p->ainsn.boostable = 1; } else { - p->ainsn.boostable = 0; + /* Otherwise, put an int3 for trapping singlestep */ + if (MAX_INSN_SIZE - len < INT3_INSN_SIZE) + return -ENOSPC; + + buf[len] = INT3_INSN_OPCODE; + len += INT3_INSN_SIZE; } return len; @@ -411,86 +428,290 @@ void free_insn_page(void *page) module_memfree(page); } -static void set_resume_flags(struct kprobe *p, struct insn *insn) +/* Kprobe x86 instruction emulation - only regs->ip or IF flag modifiers */ + +static void kprobe_emulate_ifmodifiers(struct kprobe *p, struct pt_regs *regs) +{ + switch (p->ainsn.opcode) { + case 0xfa: /* cli */ + regs->flags &= ~(X86_EFLAGS_IF); + break; + case 0xfb: /* sti */ + regs->flags |= X86_EFLAGS_IF; + break; + case 0x9c: /* pushf */ + int3_emulate_push(regs, regs->flags); + break; + case 0x9d: /* popf */ + regs->flags = int3_emulate_pop(regs); + break; + } + regs->ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size; +} +NOKPROBE_SYMBOL(kprobe_emulate_ifmodifiers); + +static void kprobe_emulate_ret(struct kprobe *p, struct pt_regs *regs) +{ + int3_emulate_ret(regs); +} +NOKPROBE_SYMBOL(kprobe_emulate_ret); + +static void kprobe_emulate_call(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long func = regs->ip - INT3_INSN_SIZE + p->ainsn.size; + + func += p->ainsn.rel32; + int3_emulate_call(regs, func); +} +NOKPROBE_SYMBOL(kprobe_emulate_call); + +static nokprobe_inline +void __kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs, bool cond) +{ + unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size; + + if (cond) + ip += p->ainsn.rel32; + int3_emulate_jmp(regs, ip); +} + +static void kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs) +{ + __kprobe_emulate_jmp(p, regs, true); +} +NOKPROBE_SYMBOL(kprobe_emulate_jmp); + +static const unsigned long jcc_mask[6] = { + [0] = X86_EFLAGS_OF, + [1] = X86_EFLAGS_CF, + [2] = X86_EFLAGS_ZF, + [3] = X86_EFLAGS_CF | X86_EFLAGS_ZF, + [4] = X86_EFLAGS_SF, + [5] = X86_EFLAGS_PF, +}; + +static void kprobe_emulate_jcc(struct kprobe *p, struct pt_regs *regs) +{ + bool invert = p->ainsn.jcc.type & 1; + bool match; + + if (p->ainsn.jcc.type < 0xc) { + match = regs->flags & jcc_mask[p->ainsn.jcc.type >> 1]; + } else { + match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^ + ((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT); + if (p->ainsn.jcc.type >= 0xe) + match = match && (regs->flags & X86_EFLAGS_ZF); + } + __kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert)); +} +NOKPROBE_SYMBOL(kprobe_emulate_jcc); + +static void kprobe_emulate_loop(struct kprobe *p, struct pt_regs *regs) +{ + bool match; + + if (p->ainsn.loop.type != 3) { /* LOOP* */ + if (p->ainsn.loop.asize == 32) + match = ((*(u32 *)®s->cx)--) != 0; +#ifdef CONFIG_X86_64 + else if (p->ainsn.loop.asize == 64) + match = ((*(u64 *)®s->cx)--) != 0; +#endif + else + match = ((*(u16 *)®s->cx)--) != 0; + } else { /* JCXZ */ + if (p->ainsn.loop.asize == 32) + match = *(u32 *)(®s->cx) == 0; +#ifdef CONFIG_X86_64 + else if (p->ainsn.loop.asize == 64) + match = *(u64 *)(®s->cx) == 0; +#endif + else + match = *(u16 *)(®s->cx) == 0; + } + + if (p->ainsn.loop.type == 0) /* LOOPNE */ + match = match && !(regs->flags & X86_EFLAGS_ZF); + else if (p->ainsn.loop.type == 1) /* LOOPE */ + match = match && (regs->flags & X86_EFLAGS_ZF); + + __kprobe_emulate_jmp(p, regs, match); +} +NOKPROBE_SYMBOL(kprobe_emulate_loop); + +static const int addrmode_regoffs[] = { + offsetof(struct pt_regs, ax), + offsetof(struct pt_regs, cx), + offsetof(struct pt_regs, dx), + offsetof(struct pt_regs, bx), + offsetof(struct pt_regs, sp), + offsetof(struct pt_regs, bp), + offsetof(struct pt_regs, si), + offsetof(struct pt_regs, di), +#ifdef CONFIG_X86_64 + offsetof(struct pt_regs, r8), + offsetof(struct pt_regs, r9), + offsetof(struct pt_regs, r10), + offsetof(struct pt_regs, r11), + offsetof(struct pt_regs, r12), + offsetof(struct pt_regs, r13), + offsetof(struct pt_regs, r14), + offsetof(struct pt_regs, r15), +#endif +}; + +static void kprobe_emulate_call_indirect(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long offs = addrmode_regoffs[p->ainsn.indirect.reg]; + + int3_emulate_call(regs, regs_get_register(regs, offs)); +} +NOKPROBE_SYMBOL(kprobe_emulate_call_indirect); + +static void kprobe_emulate_jmp_indirect(struct kprobe *p, struct pt_regs *regs) +{ + unsigned long offs = addrmode_regoffs[p->ainsn.indirect.reg]; + + int3_emulate_jmp(regs, regs_get_register(regs, offs)); +} +NOKPROBE_SYMBOL(kprobe_emulate_jmp_indirect); + +static int prepare_emulation(struct kprobe *p, struct insn *insn) { insn_byte_t opcode = insn->opcode.bytes[0]; switch (opcode) { case 0xfa: /* cli */ case 0xfb: /* sti */ + case 0x9c: /* pushfl */ case 0x9d: /* popf/popfd */ - /* Check whether the instruction modifies Interrupt Flag or not */ - p->ainsn.if_modifier = 1; - break; - case 0x9c: /* pushfl */ - p->ainsn.is_pushf = 1; + /* + * IF modifiers must be emulated since it will enable interrupt while + * int3 single stepping. + */ + p->ainsn.emulate_op = kprobe_emulate_ifmodifiers; + p->ainsn.opcode = opcode; break; - case 0xcf: /* iret */ - p->ainsn.if_modifier = 1; - fallthrough; case 0xc2: /* ret/lret */ case 0xc3: case 0xca: case 0xcb: - case 0xea: /* jmp absolute -- ip is correct */ - /* ip is already adjusted, no more changes required */ - p->ainsn.is_abs_ip = 1; - /* Without resume jump, this is boostable */ - p->ainsn.boostable = 1; + p->ainsn.emulate_op = kprobe_emulate_ret; break; - case 0xe8: /* call relative - Fix return addr */ - p->ainsn.is_call = 1; + case 0x9a: /* far call absolute -- segment is not supported */ + case 0xea: /* far jmp absolute -- segment is not supported */ + case 0xcc: /* int3 */ + case 0xcf: /* iret -- in-kernel IRET is not supported */ + return -EOPNOTSUPP; break; -#ifdef CONFIG_X86_32 - case 0x9a: /* call absolute -- same as call absolute, indirect */ - p->ainsn.is_call = 1; - p->ainsn.is_abs_ip = 1; + case 0xe8: /* near call relative */ + p->ainsn.emulate_op = kprobe_emulate_call; + if (insn->immediate.nbytes == 2) + p->ainsn.rel32 = *(s16 *)&insn->immediate.value; + else + p->ainsn.rel32 = *(s32 *)&insn->immediate.value; break; -#endif - case 0xff: + case 0xeb: /* short jump relative */ + case 0xe9: /* near jump relative */ + p->ainsn.emulate_op = kprobe_emulate_jmp; + if (insn->immediate.nbytes == 1) + p->ainsn.rel32 = *(s8 *)&insn->immediate.value; + else if (insn->immediate.nbytes == 2) + p->ainsn.rel32 = *(s16 *)&insn->immediate.value; + else + p->ainsn.rel32 = *(s32 *)&insn->immediate.value; + break; + case 0x70 ... 0x7f: + /* 1 byte conditional jump */ + p->ainsn.emulate_op = kprobe_emulate_jcc; + p->ainsn.jcc.type = opcode & 0xf; + p->ainsn.rel32 = *(char *)insn->immediate.bytes; + break; + case 0x0f: opcode = insn->opcode.bytes[1]; + if ((opcode & 0xf0) == 0x80) { + /* 2 bytes Conditional Jump */ + p->ainsn.emulate_op = kprobe_emulate_jcc; + p->ainsn.jcc.type = opcode & 0xf; + if (insn->immediate.nbytes == 2) + p->ainsn.rel32 = *(s16 *)&insn->immediate.value; + else + p->ainsn.rel32 = *(s32 *)&insn->immediate.value; + } else if (opcode == 0x01 && + X86_MODRM_REG(insn->modrm.bytes[0]) == 0 && + X86_MODRM_MOD(insn->modrm.bytes[0]) == 3) { + /* VM extensions - not supported */ + return -EOPNOTSUPP; + } + break; + case 0xe0: /* Loop NZ */ + case 0xe1: /* Loop */ + case 0xe2: /* Loop */ + case 0xe3: /* J*CXZ */ + p->ainsn.emulate_op = kprobe_emulate_loop; + p->ainsn.loop.type = opcode & 0x3; + p->ainsn.loop.asize = insn->addr_bytes * 8; + p->ainsn.rel32 = *(s8 *)&insn->immediate.value; + break; + case 0xff: + /* + * Since the 0xff is an extended group opcode, the instruction + * is determined by the MOD/RM byte. + */ + opcode = insn->modrm.bytes[0]; if ((opcode & 0x30) == 0x10) { - /* - * call absolute, indirect - * Fix return addr; ip is correct. - * But this is not boostable - */ - p->ainsn.is_call = 1; - p->ainsn.is_abs_ip = 1; + if ((opcode & 0x8) == 0x8) + return -EOPNOTSUPP; /* far call */ + /* call absolute, indirect */ + p->ainsn.emulate_op = kprobe_emulate_call_indirect; + } else if ((opcode & 0x30) == 0x20) { + if ((opcode & 0x8) == 0x8) + return -EOPNOTSUPP; /* far jmp */ + /* jmp near absolute indirect */ + p->ainsn.emulate_op = kprobe_emulate_jmp_indirect; + } else break; - } else if (((opcode & 0x31) == 0x20) || - ((opcode & 0x31) == 0x21)) { - /* - * jmp near and far, absolute indirect - * ip is correct. - */ - p->ainsn.is_abs_ip = 1; - /* Without resume jump, this is boostable */ - p->ainsn.boostable = 1; - } + + if (insn->addr_bytes != sizeof(unsigned long)) + return -EOPNOTSUPP; /* Don't support differnt size */ + if (X86_MODRM_MOD(opcode) != 3) + return -EOPNOTSUPP; /* TODO: support memory addressing */ + + p->ainsn.indirect.reg = X86_MODRM_RM(opcode); +#ifdef CONFIG_X86_64 + if (X86_REX_B(insn->rex_prefix.value)) + p->ainsn.indirect.reg += 8; +#endif + break; + default: break; } + p->ainsn.size = insn->length; + + return 0; } static int arch_copy_kprobe(struct kprobe *p) { struct insn insn; kprobe_opcode_t buf[MAX_INSN_SIZE]; - int len; + int ret, len; /* Copy an instruction with recovering if other optprobe modifies it.*/ len = __copy_instruction(buf, p->addr, p->ainsn.insn, &insn); if (!len) return -EINVAL; - /* - * __copy_instruction can modify the displacement of the instruction, - * but it doesn't affect boostable check. - */ - len = prepare_boost(buf, p, &insn); + /* Analyze the opcode and setup emulate functions */ + ret = prepare_emulation(p, &insn); + if (ret < 0) + return ret; - /* Analyze the opcode and set resume flags */ - set_resume_flags(p, &insn); + /* Add int3 for single-step or booster jmp */ + len = prepare_singlestep(buf, p, &insn); + if (len < 0) + return len; /* Also, displacement change doesn't affect the first byte */ p->opcode = buf[0]; @@ -583,29 +804,7 @@ set_current_kprobe(struct kprobe *p, struct pt_regs *regs, { __this_cpu_write(current_kprobe, p); kcb->kprobe_saved_flags = kcb->kprobe_old_flags - = (regs->flags & (X86_EFLAGS_TF | X86_EFLAGS_IF)); - if (p->ainsn.if_modifier) - kcb->kprobe_saved_flags &= ~X86_EFLAGS_IF; -} - -static nokprobe_inline void clear_btf(void) -{ - if (test_thread_flag(TIF_BLOCKSTEP)) { - unsigned long debugctl = get_debugctlmsr(); - - debugctl &= ~DEBUGCTLMSR_BTF; - update_debugctlmsr(debugctl); - } -} - -static nokprobe_inline void restore_btf(void) -{ - if (test_thread_flag(TIF_BLOCKSTEP)) { - unsigned long debugctl = get_debugctlmsr(); - - debugctl |= DEBUGCTLMSR_BTF; - update_debugctlmsr(debugctl); - } + = (regs->flags & X86_EFLAGS_IF); } void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) @@ -620,6 +819,22 @@ void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) } NOKPROBE_SYMBOL(arch_prepare_kretprobe); +static void kprobe_post_process(struct kprobe *cur, struct pt_regs *regs, + struct kprobe_ctlblk *kcb) +{ + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + cur->post_handler(cur, regs, 0); + } + + /* Restore back the original saved kprobes variables and continue. */ + if (kcb->kprobe_status == KPROBE_REENTER) + restore_previous_kprobe(kcb); + else + reset_current_kprobe(); +} +NOKPROBE_SYMBOL(kprobe_post_process); + static void setup_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb, int reenter) { @@ -627,7 +842,7 @@ static void setup_singlestep(struct kprobe *p, struct pt_regs *regs, return; #if !defined(CONFIG_PREEMPTION) - if (p->ainsn.boostable && !p->post_handler) { + if (p->ainsn.boostable) { /* Boost up -- we can execute copied instructions directly */ if (!reenter) reset_current_kprobe(); @@ -646,19 +861,51 @@ static void setup_singlestep(struct kprobe *p, struct pt_regs *regs, kcb->kprobe_status = KPROBE_REENTER; } else kcb->kprobe_status = KPROBE_HIT_SS; - /* Prepare real single stepping */ - clear_btf(); - regs->flags |= X86_EFLAGS_TF; + + if (p->ainsn.emulate_op) { + p->ainsn.emulate_op(p, regs); + kprobe_post_process(p, regs, kcb); + return; + } + + /* Disable interrupt, and set ip register on trampoline */ regs->flags &= ~X86_EFLAGS_IF; - /* single step inline if the instruction is an int3 */ - if (p->opcode == INT3_INSN_OPCODE) - regs->ip = (unsigned long)p->addr; - else - regs->ip = (unsigned long)p->ainsn.insn; + regs->ip = (unsigned long)p->ainsn.insn; } NOKPROBE_SYMBOL(setup_singlestep); /* + * Called after single-stepping. p->addr is the address of the + * instruction whose first byte has been replaced by the "int3" + * instruction. To avoid the SMP problems that can occur when we + * temporarily put back the original opcode to single-step, we + * single-stepped a copy of the instruction. The address of this + * copy is p->ainsn.insn. We also doesn't use trap, but "int3" again + * right after the copied instruction. + * Different from the trap single-step, "int3" single-step can not + * handle the instruction which changes the ip register, e.g. jmp, + * call, conditional jmp, and the instructions which changes the IF + * flags because interrupt must be disabled around the single-stepping. + * Such instructions are software emulated, but others are single-stepped + * using "int3". + * + * When the 2nd "int3" handled, the regs->ip and regs->flags needs to + * be adjusted, so that we can resume execution on correct code. + */ +static void resume_singlestep(struct kprobe *p, struct pt_regs *regs, + struct kprobe_ctlblk *kcb) +{ + unsigned long copy_ip = (unsigned long)p->ainsn.insn; + unsigned long orig_ip = (unsigned long)p->addr; + + /* Restore saved interrupt flag and ip register */ + regs->flags |= kcb->kprobe_saved_flags; + /* Note that regs->ip is executed int3 so must be a step back */ + regs->ip += (orig_ip - copy_ip) - INT3_INSN_SIZE; +} +NOKPROBE_SYMBOL(resume_singlestep); + +/* * We have reentered the kprobe_handler(), since another probe was hit while * within the handler. We save the original kprobes variables and just single * step on the instruction of the new probe without calling any user handlers. @@ -693,6 +940,12 @@ static int reenter_kprobe(struct kprobe *p, struct pt_regs *regs, } NOKPROBE_SYMBOL(reenter_kprobe); +static nokprobe_inline int kprobe_is_ss(struct kprobe_ctlblk *kcb) +{ + return (kcb->kprobe_status == KPROBE_HIT_SS || + kcb->kprobe_status == KPROBE_REENTER); +} + /* * Interrupts are disabled on entry as trap3 is an interrupt gate and they * remain disabled throughout this function. @@ -737,7 +990,18 @@ int kprobe_int3_handler(struct pt_regs *regs) reset_current_kprobe(); return 1; } - } else if (*addr != INT3_INSN_OPCODE) { + } else if (kprobe_is_ss(kcb)) { + p = kprobe_running(); + if ((unsigned long)p->ainsn.insn < regs->ip && + (unsigned long)p->ainsn.insn + MAX_INSN_SIZE > regs->ip) { + /* Most provably this is the second int3 for singlestep */ + resume_singlestep(p, regs, kcb); + kprobe_post_process(p, regs, kcb); + return 1; + } + } + + if (*addr != INT3_INSN_OPCODE) { /* * The breakpoint instruction was removed right * after we hit it. Another cpu has removed @@ -810,91 +1074,6 @@ __used __visible void *trampoline_handler(struct pt_regs *regs) } NOKPROBE_SYMBOL(trampoline_handler); -/* - * Called after single-stepping. p->addr is the address of the - * instruction whose first byte has been replaced by the "int 3" - * instruction. To avoid the SMP problems that can occur when we - * temporarily put back the original opcode to single-step, we - * single-stepped a copy of the instruction. The address of this - * copy is p->ainsn.insn. - * - * This function prepares to return from the post-single-step - * interrupt. We have to fix up the stack as follows: - * - * 0) Except in the case of absolute or indirect jump or call instructions, - * the new ip is relative to the copied instruction. We need to make - * it relative to the original instruction. - * - * 1) If the single-stepped instruction was pushfl, then the TF and IF - * flags are set in the just-pushed flags, and may need to be cleared. - * - * 2) If the single-stepped instruction was a call, the return address - * that is atop the stack is the address following the copied instruction. - * We need to make it the address following the original instruction. - */ -static void resume_execution(struct kprobe *p, struct pt_regs *regs, - struct kprobe_ctlblk *kcb) -{ - unsigned long *tos = stack_addr(regs); - unsigned long copy_ip = (unsigned long)p->ainsn.insn; - unsigned long orig_ip = (unsigned long)p->addr; - - regs->flags &= ~X86_EFLAGS_TF; - - /* Fixup the contents of top of stack */ - if (p->ainsn.is_pushf) { - *tos &= ~(X86_EFLAGS_TF | X86_EFLAGS_IF); - *tos |= kcb->kprobe_old_flags; - } else if (p->ainsn.is_call) { - *tos = orig_ip + (*tos - copy_ip); - } - - if (!p->ainsn.is_abs_ip) - regs->ip += orig_ip - copy_ip; - - restore_btf(); -} -NOKPROBE_SYMBOL(resume_execution); - -/* - * Interrupts are disabled on entry as trap1 is an interrupt gate and they - * remain disabled throughout this function. - */ -int kprobe_debug_handler(struct pt_regs *regs) -{ - struct kprobe *cur = kprobe_running(); - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - if (!cur) - return 0; - - resume_execution(cur, regs, kcb); - regs->flags |= kcb->kprobe_saved_flags; - - if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { - kcb->kprobe_status = KPROBE_HIT_SSDONE; - cur->post_handler(cur, regs, 0); - } - - /* Restore back the original saved kprobes variables and continue. */ - if (kcb->kprobe_status == KPROBE_REENTER) { - restore_previous_kprobe(kcb); - goto out; - } - reset_current_kprobe(); -out: - /* - * if somebody else is singlestepping across a probe point, flags - * will have TF set, in which case, continue the remaining processing - * of do_debug, as if this is not a probe hit. - */ - if (regs->flags & X86_EFLAGS_TF) - return 0; - - return 1; -} -NOKPROBE_SYMBOL(kprobe_debug_handler); - int kprobe_fault_handler(struct pt_regs *regs, int trapnr) { struct kprobe *cur = kprobe_running(); @@ -912,20 +1091,9 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) * normal page fault. */ regs->ip = (unsigned long)cur->addr; - /* - * Trap flag (TF) has been set here because this fault - * happened where the single stepping will be done. - * So clear it by resetting the current kprobe: - */ - regs->flags &= ~X86_EFLAGS_TF; - /* - * Since the single step (trap) has been cancelled, - * we need to restore BTF here. - */ - restore_btf(); /* - * If the TF flag was set before the kprobe hit, + * If the IF flag was set before the kprobe hit, * don't touch it: */ regs->flags |= kcb->kprobe_old_flags; |