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

From: tip-bot2 for Thomas Gleixner
Date: Tue May 19 2020 - 15:58:31 EST


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,