From 62edab9056a6cf0c9207339c8892c923a5217e45 Mon Sep 17 00:00:00 2001 From: "K.Prasad" Date: Mon, 1 Jun 2009 23:47:06 +0530 Subject: hw-breakpoints: reset bits in dr6 after the corresponding exception is handled This patch resets the bit in dr6 after the corresponding exception is handled in code, so that we keep a clean track of the current virtual debug status register. [ Impact: keep track of breakpoints triggering completion ] Signed-off-by: K.Prasad Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/kprobes.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/kprobes.c') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 7b5169d2b000..b5b1848c5336 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -54,6 +54,7 @@ #include #include #include +#include void jprobe_return_end(void); @@ -967,8 +968,14 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, ret = NOTIFY_STOP; break; case DIE_DEBUG: - if (post_kprobe_handler(args->regs)) + if (post_kprobe_handler(args->regs)) { + /* + * Reset the BS bit in dr6 (pointed by args->err) to + * denote completion of processing + */ + (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP; ret = NOTIFY_STOP; + } break; case DIE_GPF: /* -- cgit v1.2.3 From b46b3d70c9c017d7c4ec49f7f3ffd0af5a622277 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 13 Aug 2009 16:34:28 -0400 Subject: kprobes: Checks probe address is instruction boudary on x86 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Ensure safeness of inserting kprobes by checking whether the specified address is at the first byte of an instruction on x86. This is done by decoding probed function from its head to the probe point. Signed-off-by: Masami Hiramatsu Acked-by: Ananth N Mavinakayanahalli Cc: Avi Kivity Cc: Andi Kleen Cc: Christoph Hellwig Cc: Frank Ch. Eigler Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Jason Baron Cc: Jim Keniston Cc: K.Prasad Cc: Lai Jiangshan Cc: Li Zefan Cc: Przemysław Pawełczyk Cc: Roland McGrath Cc: Sam Ravnborg Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: Tom Zanussi Cc: Vegard Nossum LKML-Reference: <20090813203428.31965.21939.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/kprobes.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) (limited to 'arch/x86/kernel/kprobes.c') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 7b5169d2b000..aa15f3e1f64b 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -48,12 +48,14 @@ #include #include #include +#include #include #include #include #include #include +#include void jprobe_return_end(void); @@ -244,6 +246,75 @@ retry: } } +/* Recover the probed instruction at addr for further analysis. */ +static int recover_probed_instruction(kprobe_opcode_t *buf, unsigned long addr) +{ + struct kprobe *kp; + kp = get_kprobe((void *)addr); + if (!kp) + return -EINVAL; + + /* + * Basically, kp->ainsn.insn has an original instruction. + * However, RIP-relative instruction can not do single-stepping + * at different place, fix_riprel() tweaks the displacement of + * that instruction. In that case, we can't recover the instruction + * from the kp->ainsn.insn. + * + * On the other hand, kp->opcode has a copy of the first byte of + * the probed instruction, which is overwritten by int3. And + * the instruction at kp->addr is not modified by kprobes except + * for the first byte, we can recover the original instruction + * from it and kp->opcode. + */ + memcpy(buf, kp->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + buf[0] = kp->opcode; + return 0; +} + +/* Dummy buffers for kallsyms_lookup */ +static char __dummy_buf[KSYM_NAME_LEN]; + +/* Check if paddr is at an instruction boundary */ +static int __kprobes can_probe(unsigned long paddr) +{ + int ret; + unsigned long addr, offset = 0; + struct insn insn; + kprobe_opcode_t buf[MAX_INSN_SIZE]; + + if (!kallsyms_lookup(paddr, NULL, &offset, NULL, __dummy_buf)) + return 0; + + /* Decode instructions */ + addr = paddr - offset; + while (addr < paddr) { + kernel_insn_init(&insn, (void *)addr); + insn_get_opcode(&insn); + + /* + * Check if the instruction has been modified by another + * kprobe, in which case we replace the breakpoint by the + * original instruction in our buffer. + */ + if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION) { + ret = recover_probed_instruction(buf, addr); + if (ret) + /* + * Another debugging subsystem might insert + * this breakpoint. In that case, we can't + * recover it. + */ + return 0; + kernel_insn_init(&insn, buf); + } + insn_get_length(&insn); + addr += insn.length; + } + + return (addr == paddr); +} + /* * Returns non-zero if opcode modifies the interrupt flag. */ @@ -359,6 +430,8 @@ static void __kprobes arch_copy_kprobe(struct kprobe *p) int __kprobes arch_prepare_kprobe(struct kprobe *p) { + if (!can_probe((unsigned long)p->addr)) + return -EILSEQ; /* insn: must be on special executable page on x86. */ p->ainsn.insn = get_insn_slot(); if (!p->ainsn.insn) -- cgit v1.2.3 From 89ae465b0ee470f7d3f8a1c61353445c3acbbe2a Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 13 Aug 2009 16:34:36 -0400 Subject: kprobes: Cleanup fix_riprel() using insn decoder on x86 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cleanup fix_riprel() in arch/x86/kernel/kprobes.c by using the new x86 instruction decoder instead of using comparisons with raw ad hoc numeric opcodes. Signed-off-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Avi Kivity Cc: Andi Kleen Cc: Christoph Hellwig Cc: Frank Ch. Eigler Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Jason Baron Cc: Jim Keniston Cc: K.Prasad Cc: Lai Jiangshan Cc: Li Zefan Cc: Przemysław Pawełczyk Cc: Roland McGrath Cc: Sam Ravnborg Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: Tom Zanussi Cc: Vegard Nossum LKML-Reference: <20090813203436.31965.34374.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/kprobes.c | 128 +++++++++------------------------------------- 1 file changed, 23 insertions(+), 105 deletions(-) (limited to 'arch/x86/kernel/kprobes.c') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index aa15f3e1f64b..16ae9610f6ff 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -108,50 +108,6 @@ static const u32 twobyte_is_boostable[256 / 32] = { /* ----------------------------------------------- */ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ }; -static const u32 onebyte_has_modrm[256 / 32] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ----------------------------------------------- */ - W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */ - W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */ - W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */ - W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */ - W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */ - W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */ - W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */ - W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */ - W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */ - W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */ - W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */ - W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */ - W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */ - W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */ - W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */ - W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) /* f0 */ - /* ----------------------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ -}; -static const u32 twobyte_has_modrm[256 / 32] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ----------------------------------------------- */ - W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */ - W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */ - W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */ - W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */ - W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */ - W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */ - W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */ - W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */ - W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */ - W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */ - W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */ - W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */ - W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */ - W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */ - W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */ - W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0) /* ff */ - /* ----------------------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ -}; #undef W struct kretprobe_blackpoint kretprobe_blacklist[] = { @@ -348,68 +304,30 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn) static void __kprobes fix_riprel(struct kprobe *p) { #ifdef CONFIG_X86_64 - u8 *insn = p->ainsn.insn; - s64 disp; - int need_modrm; - - /* Skip legacy instruction prefixes. */ - while (1) { - switch (*insn) { - case 0x66: - case 0x67: - case 0x2e: - case 0x3e: - case 0x26: - case 0x64: - case 0x65: - case 0x36: - case 0xf0: - case 0xf3: - case 0xf2: - ++insn; - continue; - } - break; - } + struct insn insn; + kernel_insn_init(&insn, p->ainsn.insn); - /* Skip REX instruction prefix. */ - if (is_REX_prefix(insn)) - ++insn; - - if (*insn == 0x0f) { - /* Two-byte opcode. */ - ++insn; - need_modrm = test_bit(*insn, - (unsigned long *)twobyte_has_modrm); - } else - /* One-byte opcode. */ - need_modrm = test_bit(*insn, - (unsigned long *)onebyte_has_modrm); - - if (need_modrm) { - u8 modrm = *++insn; - if ((modrm & 0xc7) == 0x05) { - /* %rip+disp32 addressing mode */ - /* Displacement follows ModRM byte. */ - ++insn; - /* - * The copied instruction uses the %rip-relative - * addressing mode. Adjust the displacement for the - * difference between the original location of this - * instruction and the location of the copy that will - * actually be run. The tricky bit here is making sure - * that the sign extension happens correctly in this - * calculation, since we need a signed 32-bit result to - * be sign-extended to 64 bits when it's added to the - * %rip value and yield the same 64-bit result that the - * sign-extension of the original signed 32-bit - * displacement would have given. - */ - disp = (u8 *) p->addr + *((s32 *) insn) - - (u8 *) p->ainsn.insn; - BUG_ON((s64) (s32) disp != disp); /* Sanity check. */ - *(s32 *)insn = (s32) disp; - } + if (insn_rip_relative(&insn)) { + s64 newdisp; + u8 *disp; + insn_get_displacement(&insn); + /* + * The copied instruction uses the %rip-relative addressing + * mode. Adjust the displacement for the difference between + * the original location of this instruction and the location + * of the copy that will actually be run. The tricky bit here + * is making sure that the sign extension happens correctly in + * this calculation, since we need a signed 32-bit result to + * be sign-extended to 64 bits when it's added to the %rip + * value and yield the same 64-bit result that the sign- + * extension of the original signed 32-bit displacement would + * have given. + */ + newdisp = (u8 *) p->addr + (s64) insn.displacement.value - + (u8 *) p->ainsn.insn; + BUG_ON((s64) (s32) newdisp != newdisp); /* Sanity check. */ + disp = (u8 *) p->ainsn.insn + insn_offset_displacement(&insn); + *(s32 *) disp = (s32) newdisp; } #endif } -- cgit v1.2.3 From 24851d2447830e6cba4c4b641cb73e713f312373 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 26 Aug 2009 23:38:30 +0200 Subject: tracing/kprobes: Dump the culprit kprobe in case of kprobe recursion Kprobes can enter into a probing recursion, ie: a kprobe that does an endless loop because one of its core mechanism function used during probing is also probed itself. This patch helps pinpointing the kprobe that raised such recursion by dumping it and raising a BUG instead of a warning (we also disarm the kprobe to try avoiding recursion in BUG itself). Having a BUG instead of a warning stops the stacktrace in the right place and doesn't pollute the logs with hundreds of traces that eventually end up in a stack overflow. Signed-off-by: Frederic Weisbecker Cc: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli --- arch/x86/kernel/kprobes.c | 8 ++++++-- include/linux/kprobes.h | 2 ++ kernel/kprobes.c | 7 +++++++ 3 files changed, 15 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/kprobes.c') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 16ae9610f6ff..ecee3d23fef8 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -490,9 +490,13 @@ static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs, /* A probe has been hit in the codepath leading up * to, or just after, single-stepping of a probed * instruction. This entire codepath should strictly - * reside in .kprobes.text section. Raise a warning - * to highlight this peculiar case. + * reside in .kprobes.text section. + * Raise a BUG or we'll continue in an endless + * reentering loop and eventually a stack overflow. */ + arch_disarm_kprobe(p); + dump_kprobe(p); + BUG(); } default: /* impossible cases */ diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index bcd9c07848be..87eb79c9dd60 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -296,6 +296,8 @@ void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); int disable_kprobe(struct kprobe *kp); int enable_kprobe(struct kprobe *kp); +void dump_kprobe(struct kprobe *kp); + #else /* !CONFIG_KPROBES: */ static inline int kprobes_built_in(void) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index ef177d653b2c..f72e96c25a38 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1141,6 +1141,13 @@ static void __kprobes kill_kprobe(struct kprobe *p) arch_remove_kprobe(p); } +void __kprobes dump_kprobe(struct kprobe *kp) +{ + printk(KERN_WARNING "Dumping kprobe:\n"); + printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", + kp->symbol_name, kp->addr, kp->offset); +} + /* Module notifier call back, checking kprobes on the module */ static int __kprobes kprobes_module_callback(struct notifier_block *nb, unsigned long val, void *data) -- cgit v1.2.3 From e9afe9e1b3fdbd56cca53959a2519e70db9c8095 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 27 Aug 2009 13:22:58 -0400 Subject: kprobes/x86: Call BUG() when reentering probe into KPROBES_HIT_SS Call BUG() when a probe have been hit on the way of kprobe processing path, because that kind of probes are currently unrecoverable (recovering it will cause an infinite loop and stack overflow). The original code seems to assume that it's caused by an int3 which another subsystem inserted on out-of-line singlestep buffer if the hitting probe is same as current probe. However, in that case, int3-hitting-address is on the out-of-line buffer and should be different from first (current) int3 address. Thus, I decided to remove the code. I also removes arch_disarm_kprobe() because it will involve other stuffs in text_poke(). Signed-off-by: Masami Hiramatsu Acked-by: Ananth N Mavinakayanahalli Cc: Ingo Molnar LKML-Reference: <20090827172258.8246.61889.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/kprobes.c | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-) (limited to 'arch/x86/kernel/kprobes.c') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index ecee3d23fef8..e0fb615ba1e9 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -482,22 +482,16 @@ static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs, kcb->kprobe_status = KPROBE_REENTER; break; case KPROBE_HIT_SS: - if (p == kprobe_running()) { - regs->flags &= ~X86_EFLAGS_TF; - regs->flags |= kcb->kprobe_saved_flags; - return 0; - } else { - /* A probe has been hit in the codepath leading up - * to, or just after, single-stepping of a probed - * instruction. This entire codepath should strictly - * reside in .kprobes.text section. - * Raise a BUG or we'll continue in an endless - * reentering loop and eventually a stack overflow. - */ - arch_disarm_kprobe(p); - dump_kprobe(p); - BUG(); - } + /* A probe has been hit in the codepath leading up to, or just + * after, single-stepping of a probed instruction. This entire + * codepath should strictly reside in .kprobes.text section. + * Raise a BUG or we'll continue in an endless reentering loop + * and eventually a stack overflow. + */ + printk(KERN_WARNING "Unrecoverable kprobe detected at %p.\n", + p->addr); + dump_kprobe(p); + BUG(); default: /* impossible cases */ WARN_ON(1); -- cgit v1.2.3 From f5ad31158d60946b9fd18c8a79c283a6bc432430 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 27 Aug 2009 13:23:04 -0400 Subject: kprobes/x86-64: Allow to reenter probe on post_handler Allow to reenter probe on the post_handler of another probe on x86-64, because x86-64 already allows reentering int3. In that case, reentered probe just increases kp.nmissed and returns. Signed-off-by: Masami Hiramatsu Acked-by: Ananth N Mavinakayanahalli Cc: Ingo Molnar LKML-Reference: <20090827172304.8246.4822.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/kprobes.c | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'arch/x86/kernel/kprobes.c') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index e0fb615ba1e9..c5f1f117e0c0 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -463,17 +463,6 @@ static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs, { switch (kcb->kprobe_status) { case KPROBE_HIT_SSDONE: -#ifdef CONFIG_X86_64 - /* TODO: Provide re-entrancy from post_kprobes_handler() and - * avoid exception stack corruption while single-stepping on - * the instruction of the new probe. - */ - arch_disarm_kprobe(p); - regs->ip = (unsigned long)p->addr; - reset_current_kprobe(); - preempt_enable_no_resched(); - break; -#endif case KPROBE_HIT_ACTIVE: save_previous_kprobe(kcb); set_current_kprobe(p, regs, kcb); -- cgit v1.2.3 From 98272ed0d2e6509fe7dc571e77956c99bf653bb6 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 12 Oct 2009 14:14:10 -0700 Subject: x86: use kernel_stack_pointer() in kprobes.c The way to obtain a kernel-mode stack pointer from a struct pt_regs in 32-bit mode is "subtle": the stack doesn't actually contain the stack pointer, but rather the location where it would have been marks the actual previous stack frame. For clarity, use kernel_stack_pointer() instead of coding this weirdness explicitly. Signed-off-by: H. Peter Anvin Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Masami Hiramatsu --- arch/x86/kernel/kprobes.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) (limited to 'arch/x86/kernel/kprobes.c') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 7b5169d2b000..2ee4fa3a3f01 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -60,19 +60,7 @@ void jprobe_return_end(void); DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); -#ifdef CONFIG_X86_64 -#define stack_addr(regs) ((unsigned long *)regs->sp) -#else -/* - * "®s->sp" looks wrong, but it's correct for x86_32. x86_32 CPUs - * don't save the ss and esp registers if the CPU is already in kernel - * mode when it traps. So for kprobes, regs->sp and regs->ss are not - * the [nonexistent] saved stack pointer and ss register, but rather - * the top 8 bytes of the pre-int3 stack. So ®s->sp happens to - * point to the top of the pre-int3 stack. - */ -#define stack_addr(regs) ((unsigned long *)®s->sp) -#endif +#define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs)) #define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\ (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ -- cgit v1.2.3