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@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135315.380927730@linutronix.de

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index b62e962871f2bbed1d3e8ea6f18fa1b7f53432dc..41bb0cb9df84ef8f8da707decbcba4d5c174ac41 100644 (file)
--- 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,