linux-kernel - [PATCH v2] x86/paravirt: Get rid of patch_site and patch

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Date:   Fri, 7 Sep 2018 22:10:50 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Juergen Gross <jgross@...e.com>, x86@...nel.org,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH v2] x86/paravirt: Get rid of patch_site and patch_default
 labels

On Fri, Sep 07, 2018 at 12:51:12PM +0200, Borislav Petkov wrote:
> Whoops, no, it is still being used. Lemme see if I can remove all the
> labels in that function.

Ok, I think I've gotten rid of them all, in both 32- and 64-bit
versions. It boots here and a bunch of all*config builds pass.

---
From: Borislav Petkov <bp@...e.de>
Date: Fri, 7 Sep 2018 12:47:10 +0200
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When CONFIG_PARAVIRT_SPINLOCKS=n, it fires

  arch/x86/kernel/paravirt_patch_64.c: In function ‘native_patch’:
  arch/x86/kernel/paravirt_patch_64.c:89:1: warning: label ‘patch_site’ defined but not used [-Wunused-label]
   patch_site:

but those labels can simply be removed by directly calling the
respective functions there.

Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Juergen Gross <jgross@...e.com>
Cc: x86@...nel.org
Cc: virtualization@...ts.linux-foundation.org
---
 arch/x86/kernel/paravirt_patch_32.c | 21 ++++++++++-----------
 arch/x86/kernel/paravirt_patch_64.c | 20 +++++++++-----------
 2 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
index d460cbcabcfe..af57f0d0789f 100644
--- a/arch/x86/kernel/paravirt_patch_32.c
+++ b/arch/x86/kernel/paravirt_patch_32.c
@@ -34,14 +34,16 @@ extern bool pv_is_native_vcpu_is_preempted(void);
 
 unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
 {
-	const unsigned char *start, *end;
+	const unsigned char *start __maybe_unused, *end __maybe_unused;
 	unsigned ret;
 
 #define PATCH_SITE(ops, x)					\
 		case PARAVIRT_PATCH(ops.x):			\
 			start = start_##ops##_##x;		\
 			end = end_##ops##_##x;			\
-			goto patch_site
+								\
+			return paravirt_patch_insns(ibuf, len, start, end);
+
 	switch (type) {
 #ifdef CONFIG_PARAVIRT_XXL
 		PATCH_SITE(irq, irq_disable);
@@ -58,27 +60,24 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
 			if (pv_is_native_spin_unlock()) {
 				start = start_lock_queued_spin_unlock;
 				end   = end_lock_queued_spin_unlock;
-				goto patch_site;
+
+				return paravirt_patch_insns(ibuf, len, start, end);
 			}
-			goto patch_default;
+			return paravirt_patch_default(type, ibuf, addr, len);
 
 		case PARAVIRT_PATCH(lock.vcpu_is_preempted):
 			if (pv_is_native_vcpu_is_preempted()) {
 				start = start_lock_vcpu_is_preempted;
 				end   = end_lock_vcpu_is_preempted;
-				goto patch_site;
+
+				return paravirt_patch_insns(ibuf, len, start, end);
 			}
-			goto patch_default;
+			return paravirt_patch_default(type, ibuf, addr, len);
 #endif
 
 	default:
-patch_default: __maybe_unused
 		ret = paravirt_patch_default(type, ibuf, addr, len);
 		break;
-
-patch_site:
-		ret = paravirt_patch_insns(ibuf, len, start, end);
-		break;
 	}
 #undef PATCH_SITE
 	return ret;
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index 5ad5bcda9dc6..2db6c615932f 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -42,14 +42,15 @@ extern bool pv_is_native_vcpu_is_preempted(void);
 
 unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
 {
-	const unsigned char *start, *end;
+	const unsigned char *start __maybe_unused, *end __maybe_unused;
 	unsigned ret;
 
 #define PATCH_SITE(ops, x)					\
 		case PARAVIRT_PATCH(ops.x):			\
 			start = start_##ops##_##x;		\
 			end = end_##ops##_##x;			\
-			goto patch_site
+								\
+			return paravirt_patch_insns(ibuf, len, start, end);
 	switch(type) {
 #ifdef CONFIG_PARAVIRT_XXL
 		PATCH_SITE(irq, restore_fl);
@@ -68,27 +69,24 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
 			if (pv_is_native_spin_unlock()) {
 				start = start_lock_queued_spin_unlock;
 				end   = end_lock_queued_spin_unlock;
-				goto patch_site;
+
+				return paravirt_patch_insns(ibuf, len, start, end);
 			}
-			goto patch_default;
+			return paravirt_patch_default(type, ibuf, addr, len);
 
 		case PARAVIRT_PATCH(lock.vcpu_is_preempted):
 			if (pv_is_native_vcpu_is_preempted()) {
 				start = start_lock_vcpu_is_preempted;
 				end   = end_lock_vcpu_is_preempted;
-				goto patch_site;
+
+				return paravirt_patch_insns(ibuf, len, start, end);
 			}
-			goto patch_default;
+			return paravirt_patch_default(type, ibuf, addr, len);
 #endif
 
 	default:
-patch_default: __maybe_unused
 		ret = paravirt_patch_default(type, ibuf, addr, len);
 		break;
-
-patch_site:
-		ret = paravirt_patch_insns(ibuf, len, start, end);
-		break;
 	}
 #undef PATCH_SITE
 	return ret;
-- 
2.17.0.582.gccdcbd54c

-- 
Regards/Gruss,
    Boris.

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