[RFC][PATCH 4/7] x86/debug: Move historical SYSENTER junk into exc_debug_kernel()

[Peter Zijlstra]

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 arch/x86/kernel/traps.c |   24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -820,18 +820,6 @@ static void handle_debug(struct pt_regs
 		goto out;
 	}
 
-	if (WARN_ON_ONCE((dr6 & DR_STEP) && !user_mode(regs))) {
-		/*
-		 * Historical junk that used to handle SYSENTER single-stepping.
-		 * This should be unreachable now.  If we survive for a while
-		 * without anyone hitting this warning, we'll turn this into
-		 * an oops.
-		 */
-		tsk->thread.debugreg6 &= ~DR_STEP;
-		set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
-		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);
@@ -874,6 +862,18 @@ static __always_inline void exc_debug_ke
 	if (kprobe_debug_handler(regs))
 		goto out;
 
+	if (WARN_ON_ONCE(dr6 & DR_STEP)) {
+		/*
+		 * Historical junk that used to handle SYSENTER single-stepping.
+		 * This should be unreachable now.  If we survive for a while
+		 * without anyone hitting this warning, we'll turn this into
+		 * an oops.
+		 */
+		dr6 &= ~DR_STEP;
+		set_thread_flag(TIF_SINGLESTEP);
+		regs->flags &= ~X86_EFLAGS_TF;
+	}
+
 	handle_debug(regs, dr6, false);
 
 out: