The following commit has been merged into the x86/entry branch of tip:
Commit-ID: 7043679a989af969e9f20cc7d90195b36f54036f
Gitweb: https://git.kernel.org/tip/7043679a989af969e9f20cc7d90195b36f54036f
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 02 Sep 2020 15:25:54 +02:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Fri, 04 Sep 2020 15:12:52 +02:00
x86/debug: Remove handle_debug(.user) argument
The handle_debug(.user) argument is used to terminate the #DB handler early
for the INT1-from-kernel case, since the kernel doesn't use INT1.
Remove the argument and handle this explicitly in #DB-from-kernel.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200902133200.907020598@xxxxxxxxxxxxx
---
arch/x86/kernel/traps.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 9cb39d3..58bc434 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -783,25 +783,18 @@ static __always_inline unsigned long debug_read_clear_dr6(void)
*
* May run on IST stack.
*/
-static void handle_debug(struct pt_regs *regs, unsigned long dr6, bool user)
+static void handle_debug(struct pt_regs *regs, unsigned long dr6)
{
struct task_struct *tsk = current;
bool user_icebp;
int si_code;
/*
- * If DR6 is zero, no point in trying to handle it. The kernel is
- * not using INT1.
- */
- if (!user && !dr6)
- return;
-
- /*
* 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 = user && !dr6;
+ user_icebp = !dr6;
/* Store the virtualized DR6 value */
tsk->thread.debugreg6 = dr6;
@@ -874,7 +867,13 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
if (kprobe_debug_handler(regs))
goto out;
- handle_debug(regs, dr6, false);
+ /*
+ * The kernel doesn't use INT1
+ */
+ if (!dr6)
+ goto out;
+
+ handle_debug(regs, dr6);
out:
instrumentation_end();
@@ -904,7 +903,7 @@ static __always_inline void exc_debug_user(struct pt_regs *regs,
irqentry_enter_from_user_mode(regs);
instrumentation_begin();
- handle_debug(regs, dr6, true);
+ handle_debug(regs, dr6);
instrumentation_end();
irqentry_exit_to_user_mode(regs);
|