The following commit has been merged into the x86/entry branch of tip:
Commit-ID: 4182e9436916a48f16207f0619562f1d3843a0c8
Gitweb: https://git.kernel.org/tip/4182e9436916a48f16207f0619562f1d3843a0c8
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 02 Sep 2020 15:25:55 +02:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Fri, 04 Sep 2020 15:12:52 +02:00
x86/debug: Simplify #DB signal code
There's no point in calculating si_code if it's not going to be used.
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/20200902133200.967434217@xxxxxxxxxxxxx
---
arch/x86/kernel/traps.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 58bc434..24e09f8 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -786,15 +786,14 @@ static __always_inline unsigned long debug_read_clear_dr6(void)
static void handle_debug(struct pt_regs *regs, unsigned long dr6)
{
struct task_struct *tsk = current;
- bool user_icebp;
- int si_code;
+ 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.
*/
- user_icebp = !dr6;
+ icebp = !dr6;
/* Store the virtualized DR6 value */
tsk->thread.debugreg6 = dr6;
@@ -813,6 +812,11 @@ static void handle_debug(struct pt_regs *regs, unsigned long dr6)
goto out;
}
+ /*
+ * Reload dr6, the notifier might have changed it.
+ */
+ dr6 = tsk->thread.debugreg6;
+
if (WARN_ON_ONCE((dr6 & DR_STEP) && !user_mode(regs))) {
/*
* Historical junk that used to handle SYSENTER single-stepping.
@@ -825,9 +829,8 @@ static void handle_debug(struct pt_regs *regs, unsigned long dr6)
regs->flags &= ~X86_EFLAGS_TF;
}
- si_code = get_si_code(tsk->thread.debugreg6);
- if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
- send_sigtrap(regs, 0, si_code);
+ if (dr6 & (DR_STEP | DR_TRAP_BITS) || icebp)
+ send_sigtrap(regs, 0, get_si_code(dr6));
out:
cond_local_irq_disable(regs);
|