x86/mce: Mark mce_start() noinstr

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0x4ae: call to __const_udelay() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-13-bp@alien8.de

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 7023d6550688fa7987e4d20b011c96dd4e8922c2..5818b837fd4d4cc1512f04aec19f8942c3b71040 100644 (file)
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1007,13 +1007,13 @@ static atomic_t global_nwo;
  * in the entry order.
  * TBD double check parallel CPU hotunplug
  */
-static int mce_start(int *no_way_out)
+static noinstr int mce_start(int *no_way_out)
 {
-       int order;
        u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC;
+       int order, ret = -1;
 
        if (!timeout)
-               return -1;
+               return ret;
 
        atomic_add(*no_way_out, &global_nwo);
        /*
@@ -1023,6 +1023,9 @@ static int mce_start(int *no_way_out)
        order = atomic_inc_return(&mce_callin);
        cpumask_clear_cpu(smp_processor_id(), &mce_missing_cpus);
 
+       /* Enable instrumentation around calls to external facilities */
+       instrumentation_begin();
+
        /*
         * Wait for everyone.
         */
@@ -1030,7 +1033,7 @@ static int mce_start(int *no_way_out)
                if (mce_timed_out(&timeout,
                                  "Timeout: Not all CPUs entered broadcast exception handler")) {
                        atomic_set(&global_nwo, 0);
-                       return -1;
+                       goto out;
                }
                ndelay(SPINUNIT);
        }
@@ -1056,7 +1059,7 @@ static int mce_start(int *no_way_out)
                        if (mce_timed_out(&timeout,
                                          "Timeout: Subject CPUs unable to finish machine check processing")) {
                                atomic_set(&global_nwo, 0);
-                               return -1;
+                               goto out;
                        }
                        ndelay(SPINUNIT);
                }
@@ -1067,7 +1070,12 @@ static int mce_start(int *no_way_out)
         */
        *no_way_out = atomic_read(&global_nwo);
 
-       return order;
+       ret = order;
+
+out:
+       instrumentation_end();
+
+       return ret;
 }
 
 /*