diff options
| author | Roland McGrath <roland@redhat.com> | 2008-01-30 13:30:54 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-30 13:30:54 +0100 |
| commit | 1ecc798c67645e0ee6eb028cb988b71b3edf4b40 (patch) | |
| tree | a0456da7328d9b07212b5845003e67c88185f1f3 | |
| parent | 10faa81e102e2b7695f386812055cd2ef9e44b4c (diff) | |
x86: debugctlmsr kprobes
This adjusts the x86 kprobes implementation to cope with per-thread
MSR_IA32_DEBUGCTLMSR being set for user mode. I haven't delved deep
enough into the kprobes code to be really sure this covers all the
cases where the user-mode BTF setting needs to be cleared or restored.
It looks about right to me.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | arch/x86/kernel/kprobes_32.c | 15 | ||||
| -rw-r--r-- | arch/x86/kernel/kprobes_64.c | 14 |
2 files changed, 29 insertions, 0 deletions
diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c index 3a020f79f82..bc4a68367cd 100644 --- a/arch/x86/kernel/kprobes_32.c +++ b/arch/x86/kernel/kprobes_32.c @@ -217,8 +217,21 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, kcb->kprobe_saved_eflags &= ~IF_MASK; } +static __always_inline void clear_btf(void) +{ + if (test_thread_flag(TIF_DEBUGCTLMSR)) + wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0); +} + +static __always_inline void restore_btf(void) +{ + if (test_thread_flag(TIF_DEBUGCTLMSR)) + wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0); +} + static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) { + clear_btf(); regs->eflags |= TF_MASK; regs->eflags &= ~IF_MASK; /*single step inline if the instruction is an int3*/ @@ -542,6 +555,8 @@ static void __kprobes resume_execution(struct kprobe *p, regs->eip = orig_eip + (regs->eip - copy_eip); no_change: + restore_btf(); + return; } diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c index 5df19a9f923..10d66e323c7 100644 --- a/arch/x86/kernel/kprobes_64.c +++ b/arch/x86/kernel/kprobes_64.c @@ -256,8 +256,21 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, kcb->kprobe_saved_rflags &= ~IF_MASK; } +static __always_inline void clear_btf(void) +{ + if (test_thread_flag(TIF_DEBUGCTLMSR)) + wrmsrl(MSR_IA32_DEBUGCTLMSR, 0); +} + +static __always_inline void restore_btf(void) +{ + if (test_thread_flag(TIF_DEBUGCTLMSR)) + wrmsrl(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr); +} + static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) { + clear_btf(); regs->eflags |= TF_MASK; regs->eflags &= ~IF_MASK; /*single step inline if the instruction is an int3*/ @@ -527,6 +540,7 @@ static void __kprobes resume_execution(struct kprobe *p, regs->rip = orig_rip + (regs->rip - copy_rip); no_change: + restore_btf(); return; } |