linux-kernel - [PATCH] x86/verify_cpu: Hide local labels

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Date:	Sun,  3 Jan 2016 23:38:53 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	X86 ML <x86@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] x86/verify_cpu: Hide local labels

From: Borislav Petkov <bp@...e.de>

... from the final ELF image's symbol table as they're not really needed
there.

Before:

$ readelf -a vmlinux | grep verify_cpu
    43: ffffffff810001a9     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu
    45: ffffffff8100028f     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu_no_longmode
    46: ffffffff810001de     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu_noamd
    47: ffffffff8100022b     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu_check
    48: ffffffff8100021c     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu_clear_xd
    49: ffffffff81000263     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu_sse_test
    50: ffffffff81000296     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu_sse_ok

After:

$ readelf -a vmlinux | grep verify_cpu
    43: ffffffff810001a9     0 NOTYPE  LOCAL  DEFAULT    1 verify_cpu

No functionality change.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/verify_cpu.S | 50 ++++++++++++++++++++++----------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/arch/x86/kernel/verify_cpu.S b/arch/x86/kernel/verify_cpu.S
index 4cf401f581e7..07efb35ee4bc 100644
--- a/arch/x86/kernel/verify_cpu.S
+++ b/arch/x86/kernel/verify_cpu.S
@@ -48,31 +48,31 @@ verify_cpu:
 	pushfl
 	popl	%eax
 	cmpl	%eax,%ebx
-	jz	verify_cpu_no_longmode	# cpu has no cpuid
+	jz	.Lverify_cpu_no_longmode	# cpu has no cpuid
 #endif
 
 	movl	$0x0,%eax		# See if cpuid 1 is implemented
 	cpuid
 	cmpl	$0x1,%eax
-	jb	verify_cpu_no_longmode	# no cpuid 1
+	jb	.Lverify_cpu_no_longmode	# no cpuid 1
 
 	xor	%di,%di
 	cmpl	$0x68747541,%ebx	# AuthenticAMD
-	jnz	verify_cpu_noamd
+	jnz	.Lverify_cpu_noamd
 	cmpl	$0x69746e65,%edx
-	jnz	verify_cpu_noamd
+	jnz	.Lverify_cpu_noamd
 	cmpl	$0x444d4163,%ecx
-	jnz	verify_cpu_noamd
+	jnz	.Lverify_cpu_noamd
 	mov	$1,%di			# cpu is from AMD
-	jmp	verify_cpu_check
+	jmp	.Lverify_cpu_check
 
-verify_cpu_noamd:
+.Lverify_cpu_noamd:
 	cmpl	$0x756e6547,%ebx        # GenuineIntel?
-	jnz	verify_cpu_check
+	jnz	.Lverify_cpu_check
 	cmpl	$0x49656e69,%edx
-	jnz	verify_cpu_check
+	jnz	.Lverify_cpu_check
 	cmpl	$0x6c65746e,%ecx
-	jnz	verify_cpu_check
+	jnz	.Lverify_cpu_check
 
 	# only call IA32_MISC_ENABLE when:
 	# family > 6 || (family == 6 && model >= 0xd)
@@ -83,59 +83,59 @@ verify_cpu_noamd:
 	andl	$0x0ff00f00, %eax	# mask family and extended family
 	shrl	$8, %eax
 	cmpl	$6, %eax
-	ja	verify_cpu_clear_xd	# family > 6, ok
-	jb	verify_cpu_check	# family < 6, skip
+	ja	.Lverify_cpu_clear_xd	# family > 6, ok
+	jb	.Lverify_cpu_check	# family < 6, skip
 
 	andl	$0x000f00f0, %ecx	# mask model and extended model
 	shrl	$4, %ecx
 	cmpl	$0xd, %ecx
-	jb	verify_cpu_check	# family == 6, model < 0xd, skip
+	jb	.Lverify_cpu_check	# family == 6, model < 0xd, skip
 
-verify_cpu_clear_xd:
+.Lverify_cpu_clear_xd:
 	movl	$MSR_IA32_MISC_ENABLE, %ecx
 	rdmsr
 	btrl	$2, %edx		# clear MSR_IA32_MISC_ENABLE_XD_DISABLE
-	jnc	verify_cpu_check	# only write MSR if bit was changed
+	jnc	.Lverify_cpu_check	# only write MSR if bit was changed
 	wrmsr
 
-verify_cpu_check:
+.Lverify_cpu_check:
 	movl    $0x1,%eax		# Does the cpu have what it takes
 	cpuid
 	andl	$REQUIRED_MASK0,%edx
 	xorl	$REQUIRED_MASK0,%edx
-	jnz	verify_cpu_no_longmode
+	jnz	.Lverify_cpu_no_longmode
 
 	movl    $0x80000000,%eax	# See if extended cpuid is implemented
 	cpuid
 	cmpl    $0x80000001,%eax
-	jb      verify_cpu_no_longmode	# no extended cpuid
+	jb      .Lverify_cpu_no_longmode	# no extended cpuid
 
 	movl    $0x80000001,%eax	# Does the cpu have what it takes
 	cpuid
 	andl    $REQUIRED_MASK1,%edx
 	xorl    $REQUIRED_MASK1,%edx
-	jnz     verify_cpu_no_longmode
+	jnz     .Lverify_cpu_no_longmode
 
-verify_cpu_sse_test:
+.Lverify_cpu_sse_test:
 	movl	$1,%eax
 	cpuid
 	andl	$SSE_MASK,%edx
 	cmpl	$SSE_MASK,%edx
-	je	verify_cpu_sse_ok
+	je	.Lverify_cpu_sse_ok
 	test	%di,%di
-	jz	verify_cpu_no_longmode	# only try to force SSE on AMD
+	jz	.Lverify_cpu_no_longmode	# only try to force SSE on AMD
 	movl	$MSR_K7_HWCR,%ecx
 	rdmsr
 	btr	$15,%eax		# enable SSE
 	wrmsr
 	xor	%di,%di			# don't loop
-	jmp	verify_cpu_sse_test	# try again
+	jmp	.Lverify_cpu_sse_test	# try again
 
-verify_cpu_no_longmode:
+.Lverify_cpu_no_longmode:
 	popf				# Restore caller passed flags
 	movl $1,%eax
 	ret
-verify_cpu_sse_ok:
+.Lverify_cpu_sse_ok:
 	popf				# Restore caller passed flags
 	xorl %eax, %eax
 	ret
-- 
2.3.5

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