[tip: x86/entry] x86/traps: Address objtool noinstr complaints in #DB

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     467a8425d10508886eb5bcc0b80e0c73da4751c4
Gitweb:        https://git.kernel.org/tip/467a8425d10508886eb5bcc0b80e0c73da4751c4
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Thu, 30 Apr 2020 11:07:20 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 19 May 2020 16:04:13 +02:00

x86/traps: Address objtool noinstr complaints in #DB

The functions invoked from handle_debug() can be instrumented. Tell objtool
about it.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200505135315.380927730@xxxxxxxxxxxxx


---
 arch/x86/kernel/traps.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index b62e962..41bb0cb 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -784,14 +784,19 @@ static void noinstr handle_debug(struct pt_regs *regs, unsigned long dr6,
 	/* Store the virtualized DR6 value */
 	tsk->thread.debugreg6 = dr6;
 
+	instrumentation_begin();
 #ifdef CONFIG_KPROBES
-	if (kprobe_debug_handler(regs))
+	if (kprobe_debug_handler(regs)) {
+		instrumentation_end();
 		return;
+	}
 #endif
 
 	if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, 0,
-		       SIGTRAP) == NOTIFY_STOP)
+		       SIGTRAP) == NOTIFY_STOP) {
+		instrumentation_end();
 		return;
+	}
 
 	/*
 	 * Let others (NMI) know that the debug stack is in use
@@ -827,6 +832,7 @@ static void noinstr handle_debug(struct pt_regs *regs, unsigned long dr6,
 out:
 	cond_local_irq_disable(regs);
 	debug_stack_usage_dec();
+	instrumentation_end();
 }
 
 static __always_inline void exc_debug_kernel(struct pt_regs *regs,