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author | Alexander van Heukelum <heukelum@fastmail.fm> | 2008-09-30 16:41:37 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-10-13 08:33:21 (GMT) |
commit | 3d2a71a596bd9c761c8487a2178e95f8a61da083 (patch) | |
tree | eb02df788007f136e20ec557009242992396c845 /arch/x86/kernel/traps_32.c | |
parent | e407d62088b7f61f38e1086062650c75a4f2757a (diff) | |
download | linux-fsl-qoriq-3d2a71a596bd9c761c8487a2178e95f8a61da083.tar.xz |
x86, traps: converge do_debug handlers
Make the x86_64-version and the i386-version of do_debug
more similar.
- introduce preempt_conditional_sti/cli to i386. The preempt-count
is now elevated during the trap handler, like on x86_64. It
does not run on a separate stack, however.
- replace an open-coded "send_sigtrap"
- copy some comments
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/traps_32.c')
-rw-r--r-- | arch/x86/kernel/traps_32.c | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c index 7eb1203..953172a 100644 --- a/arch/x86/kernel/traps_32.c +++ b/arch/x86/kernel/traps_32.c @@ -88,6 +88,20 @@ static inline void conditional_sti(struct pt_regs *regs) local_irq_enable(); } +static inline void preempt_conditional_sti(struct pt_regs *regs) +{ + inc_preempt_count(); + if (regs->flags & X86_EFLAGS_IF) + local_irq_enable(); +} + +static inline void preempt_conditional_cli(struct pt_regs *regs) +{ + if (regs->flags & X86_EFLAGS_IF) + local_irq_disable(); + dec_preempt_count(); +} + static inline void die_if_kernel(const char *str, struct pt_regs *regs, long err) { @@ -498,7 +512,7 @@ dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code) dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) { struct task_struct *tsk = current; - unsigned int condition; + unsigned long condition; int si_code; get_debugreg(condition, 6); @@ -512,9 +526,9 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code, SIGTRAP) == NOTIFY_STOP) return; + /* It's safe to allow irq's after DR6 has been saved */ - if (regs->flags & X86_EFLAGS_IF) - local_irq_enable(); + preempt_conditional_sti(regs); /* Mask out spurious debug traps due to lazy DR7 setting */ if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) { @@ -533,16 +547,11 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) * kernel space (but re-enable TF when returning to user mode). */ if (condition & DR_STEP) { - /* - * We already checked v86 mode above, so we can - * check for kernel mode by just checking the CPL - * of CS. - */ if (!user_mode(regs)) goto clear_TF_reenable; } - si_code = get_si_code((unsigned long)condition); + si_code = get_si_code(condition); /* Ok, finally something we can handle */ send_sigtrap(tsk, regs, error_code, si_code); @@ -552,15 +561,18 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) */ clear_dr7: set_debugreg(0, 7); + preempt_conditional_cli(regs); return; debug_vm86: handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1); + preempt_conditional_cli(regs); return; clear_TF_reenable: set_tsk_thread_flag(tsk, TIF_SINGLESTEP); regs->flags &= ~X86_EFLAGS_TF; + preempt_conditional_cli(regs); return; } |