[PATCH v2] x86/paravirt: Cleanup native_patch()

[Borislav Petkov]

When CONFIG_PARAVIRT_SPINLOCKS=n, it fires

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

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

Get rid of local variables too, while at it. Also, simplify function
flow for better readability.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
---

Here it is, rebased ontop of rc3+tip/master.


 arch/x86/kernel/paravirt_patch_32.c | 44 ++++++++++-----------------
 arch/x86/kernel/paravirt_patch_64.c | 46 +++++++++++------------------
 2 files changed, 33 insertions(+), 57 deletions(-)

diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
index d460cbcabcfe..6368c22fa1fa 100644
--- a/arch/x86/kernel/paravirt_patch_32.c
+++ b/arch/x86/kernel/paravirt_patch_32.c
@@ -34,14 +34,10 @@ 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;
-	unsigned ret;
-
 #define PATCH_SITE(ops, x)					\
-		case PARAVIRT_PATCH(ops.x):			\
-			start = start_##ops##_##x;		\
-			end = end_##ops##_##x;			\
-			goto patch_site
+	case PARAVIRT_PATCH(ops.x):				\
+		return paravirt_patch_insns(ibuf, len, start_##ops##_##x, end_##ops##_##x)
+
 	switch (type) {
 #ifdef CONFIG_PARAVIRT_XXL
 		PATCH_SITE(irq, irq_disable);
@@ -54,32 +50,24 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
 		PATCH_SITE(mmu, write_cr3);
 #endif
 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
-		case PARAVIRT_PATCH(lock.queued_spin_unlock):
-			if (pv_is_native_spin_unlock()) {
-				start = start_lock_queued_spin_unlock;
-				end   = end_lock_queued_spin_unlock;
-				goto patch_site;
-			}
-			goto patch_default;
+	case PARAVIRT_PATCH(lock.queued_spin_unlock):
+		if (pv_is_native_spin_unlock())
+			return paravirt_patch_insns(ibuf, len,
+						    start_lock_queued_spin_unlock,
+						    end_lock_queued_spin_unlock);
+		break;
 
-		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;
-			}
-			goto patch_default;
+	case PARAVIRT_PATCH(lock.vcpu_is_preempted):
+		if (pv_is_native_vcpu_is_preempted())
+			return paravirt_patch_insns(ibuf, len,
+						    start_lock_vcpu_is_preempted,
+						    end_lock_vcpu_is_preempted);
+		break;
 #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;
+	return paravirt_patch_default(type, ibuf, addr, len);
 }
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index 5ad5bcda9dc6..7ca9cb726f4d 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -42,15 +42,11 @@ 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;
-	unsigned ret;
-
 #define PATCH_SITE(ops, x)					\
-		case PARAVIRT_PATCH(ops.x):			\
-			start = start_##ops##_##x;		\
-			end = end_##ops##_##x;			\
-			goto patch_site
-	switch(type) {
+	case PARAVIRT_PATCH(ops.x):				\
+		return paravirt_patch_insns(ibuf, len, start_##ops##_##x, end_##ops##_##x)
+
+	switch (type) {
 #ifdef CONFIG_PARAVIRT_XXL
 		PATCH_SITE(irq, restore_fl);
 		PATCH_SITE(irq, save_fl);
@@ -64,32 +60,24 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
 		PATCH_SITE(mmu, write_cr3);
 #endif
 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
-		case PARAVIRT_PATCH(lock.queued_spin_unlock):
-			if (pv_is_native_spin_unlock()) {
-				start = start_lock_queued_spin_unlock;
-				end   = end_lock_queued_spin_unlock;
-				goto patch_site;
-			}
-			goto patch_default;
+	case PARAVIRT_PATCH(lock.queued_spin_unlock):
+		if (pv_is_native_spin_unlock())
+			return paravirt_patch_insns(ibuf, len,
+						    start_lock_queued_spin_unlock,
+						    end_lock_queued_spin_unlock);
+		break;
 
-		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;
-			}
-			goto patch_default;
+	case PARAVIRT_PATCH(lock.vcpu_is_preempted):
+		if (pv_is_native_vcpu_is_preempted())
+			return paravirt_patch_insns(ibuf, len,
+						    start_lock_vcpu_is_preempted,
+						    end_lock_vcpu_is_preempted);
+		break;
 #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;
+	return paravirt_patch_default(type, ibuf, addr, len);
 }
-- 
2.17.0.582.gccdcbd54c

-- 
Regards/Gruss,
    Boris.

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