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authorAlexander van Heukelum <heukelum@fastmail.fm>2008-09-30 18:41:37 +0200
committerIngo Molnar <mingo@elte.hu>2008-10-13 10:33:21 +0200
commit3d2a71a596bd9c761c8487a2178e95f8a61da083 (patch)
treeeb02df788007f136e20ec557009242992396c845 /arch/x86
parente407d62088b7f61f38e1086062650c75a4f2757a (diff)
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')
-rw-r--r--arch/x86/kernel/traps_32.c30
-rw-r--r--arch/x86/kernel/traps_64.c17
2 files changed, 30 insertions, 17 deletions
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index 7eb1203c909..953172af6e5 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;
}
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index be73323ca95..a851eca6d04 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -380,7 +380,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk = current;
unsigned long condition;
- siginfo_t info;
+ int si_code;
get_debugreg(condition, 6);
@@ -394,6 +394,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
SIGTRAP) == NOTIFY_STOP)
return;
+ /* It's safe to allow irq's after DR6 has been saved */
preempt_conditional_sti(regs);
/* Mask out spurious debug traps due to lazy DR7 setting */
@@ -402,6 +403,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
goto clear_dr7;
}
+ /* Save debug status register where ptrace can see it */
tsk->thread.debugreg6 = condition;
/*
@@ -413,15 +415,14 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
goto clear_TF_reenable;
}
+ si_code = get_si_code(condition);
/* Ok, finally something we can handle */
- tsk->thread.trap_no = 1;
- tsk->thread.error_code = error_code;
- info.si_signo = SIGTRAP;
- info.si_errno = 0;
- info.si_code = get_si_code(condition);
- info.si_addr = user_mode(regs) ? (void __user *)regs->ip : NULL;
- force_sig_info(SIGTRAP, &info, tsk);
+ send_sigtrap(tsk, regs, error_code, si_code);
+ /*
+ * Disable additional traps. They'll be re-enabled when
+ * the signal is delivered.
+ */
clear_dr7:
set_debugreg(0, 7);
preempt_conditional_cli(regs);