x86/paravirt: Fix native_patch()

While chasing a regression I noticed we potentially patch the wrong
code in native_patch().

If we do not select the native code sequence, we must use the default
patcher, not fall-through the switch case.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel test robot <xiaolong.ye@intel.com>
Fixes: 3cded4179481 ("x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()")
Link: http://lkml.kernel.org/r/20161208154349.270616999@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
index ff03dbd28625..33cdec221f3d 100644
--- a/arch/x86/kernel/paravirt_patch_32.c
+++ b/arch/x86/kernel/paravirt_patch_32.c
@@ -58,15 +58,19 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
                                 end   = end_pv_lock_ops_queued_spin_unlock;
                                 goto patch_site;
                         }
+                        goto patch_default;
+
                 case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
                         if (pv_is_native_vcpu_is_preempted()) {
                                 start = start_pv_lock_ops_vcpu_is_preempted;
                                 end   = end_pv_lock_ops_vcpu_is_preempted;
                                 goto patch_site;
                         }
+                        goto patch_default;
 #endif
 
         default:
+patch_default:
                 ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
                 break;
 
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index e61dd9791f4f..b0fceff502b3 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -70,15 +70,19 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
                                 end   = end_pv_lock_ops_queued_spin_unlock;
                                 goto patch_site;
                         }
+                        goto patch_default;
+
                 case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
                         if (pv_is_native_vcpu_is_preempted()) {
                                 start = start_pv_lock_ops_vcpu_is_preempted;
                                 end   = end_pv_lock_ops_vcpu_is_preempted;
                                 goto patch_site;
                         }
+                        goto patch_default;
 #endif
 
         default:
+patch_default:
                 ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
                 break;