linux-kernel - [tip:locking/core] x86/paravirt: Fix native

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Date:   Sun, 11 Dec 2016 22:49:43 -0800
From:   tip-bot for Peter Zijlstra <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, akataria@...are.com, hpa@...or.com,
        peterz@...radead.org, rusty@...tcorp.com.au, chrisw@...s-sol.org,
        linux-kernel@...r.kernel.org, jeremy@...p.org,
        torvalds@...ux-foundation.org, pbonzini@...hat.com,
        mingo@...nel.org, bp@...en8.de, xiaolong.ye@...el.com,
        xinhui.pan@...ux.vnet.ibm.com
Subject: [tip:locking/core] x86/paravirt: Fix native_patch()

Commit-ID:  45dbea5f55c05980cbb4c30047c71a820cd3f282
Gitweb:     http://git.kernel.org/tip/45dbea5f55c05980cbb4c30047c71a820cd3f282
Author:     Peter Zijlstra <peterz@...radead.org>
AuthorDate: Thu, 8 Dec 2016 16:42:14 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Sun, 11 Dec 2016 13:09:19 +0100

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@...radead.org>
Cc: Alok Kataria <akataria@...are.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Chris Wright <chrisw@...s-sol.org>
Cc: Jeremy Fitzhardinge <jeremy@...p.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Pan Xinhui <xinhui.pan@...ux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Peter Anvin <hpa@...or.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rusty Russell <rusty@...tcorp.com.au>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: kernel test robot <xiaolong.ye@...el.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@...nel.org>
---
 arch/x86/kernel/paravirt_patch_32.c | 4 ++++
 arch/x86/kernel/paravirt_patch_64.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
index ff03dbd..33cdec2 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 e61dd97..b0fceff 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;