The following commit has been merged into the x86/entry branch of tip:
Commit-ID: f0b67c39c190e19bc1604a13bcc985c4445a4b2f
Gitweb: https://git.kernel.org/tip/f0b67c39c190e19bc1604a13bcc985c4445a4b2f
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 02 Sep 2020 15:25:57 +02:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Fri, 04 Sep 2020 15:12:53 +02:00
x86/debug: Move cond_local_irq_enable() block into exc_debug_user()
The cond_local_irq_enable() block, dealing with vm86 and sending
signals is only relevant for #DB-from-user, move it there.
This then reduces handle_debug() to only the notifier call, so rename
it to notify_debug().
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200902133201.094265982@xxxxxxxxxxxxx
---
arch/x86/kernel/traps.c | 58 ++++++++++++++++++++--------------------
1 file changed, 29 insertions(+), 29 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 2605686..682af24 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -783,17 +783,10 @@ static __always_inline unsigned long debug_read_clear_dr6(void)
*
* May run on IST stack.
*/
-static bool handle_debug(struct pt_regs *regs, unsigned long *dr6)
+
+static bool notify_debug(struct pt_regs *regs, unsigned long *dr6)
{
struct task_struct *tsk = current;
- bool icebp;
-
- /*
- * If dr6 has no reason to give us about the origin of this trap,
- * then it's very likely the result of an icebp/int01 trap.
- * User wants a sigtrap for that.
- */
- icebp = !*dr6;
/* Store the virtualized DR6 value */
tsk->thread.debugreg6 = *dr6;
@@ -801,26 +794,9 @@ static bool handle_debug(struct pt_regs *regs, unsigned long *dr6)
if (notify_die(DIE_DEBUG, "debug", regs, (long)dr6, 0, SIGTRAP) == NOTIFY_STOP)
return true;
- /* It's safe to allow irq's after DR6 has been saved */
- cond_local_irq_enable(regs);
-
- if (v8086_mode(regs)) {
- handle_vm86_trap((struct kernel_vm86_regs *) regs, 0,
- X86_TRAP_DB);
- goto out;
- }
-
- /*
- * Reload dr6, the notifier might have changed it.
- */
+ /* Reload the DR6 value, the notifier might have changed it */
*dr6 = tsk->thread.debugreg6;
- if (*dr6 & (DR_STEP | DR_TRAP_BITS) || icebp)
- send_sigtrap(regs, 0, get_si_code(*dr6));
-
-out:
- cond_local_irq_disable(regs);
-
return false;
}
@@ -864,7 +840,7 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
if (!dr6)
goto out;
- if (handle_debug(regs, &dr6))
+ if (notify_debug(regs, &dr6))
goto out;
if (WARN_ON_ONCE(dr6 & DR_STEP)) {
@@ -889,6 +865,8 @@ out:
static __always_inline void exc_debug_user(struct pt_regs *regs,
unsigned long dr6)
{
+ bool icebp;
+
/*
* If something gets miswired and we end up here for a kernel mode
* #DB, we will malfunction.
@@ -907,8 +885,30 @@ static __always_inline void exc_debug_user(struct pt_regs *regs,
irqentry_enter_from_user_mode(regs);
instrumentation_begin();
- handle_debug(regs, &dr6);
+ /*
+ * If dr6 has no reason to give us about the origin of this trap,
+ * then it's very likely the result of an icebp/int01 trap.
+ * User wants a sigtrap for that.
+ */
+ icebp = !dr6;
+
+ if (notify_debug(regs, &dr6))
+ goto out;
+ /* It's safe to allow irq's after DR6 has been saved */
+ local_irq_enable();
+
+ if (v8086_mode(regs)) {
+ handle_vm86_trap((struct kernel_vm86_regs *)regs, 0, X86_TRAP_DB);
+ goto out_irq;
+ }
+
+ if (dr6 & (DR_STEP | DR_TRAP_BITS) || icebp)
+ send_sigtrap(regs, 0, get_si_code(dr6));
+
+out_irq:
+ local_irq_disable();
+out:
instrumentation_end();
irqentry_exit_to_user_mode(regs);
}
|