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Subject[tip:x86/asm] x86/boot: Hide local labels in verify_cpu()
Commit-ID:  aa0421410fc540832f0fd267ff0f2657c3276053
Gitweb: http://git.kernel.org/tip/aa0421410fc540832f0fd267ff0f2657c3276053
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Sun, 3 Jan 2016 23:38:53 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 12 Jan 2016 11:54:32 +0100

x86/boot: Hide local labels in verify_cpu()

... 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@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1451860733-21163-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
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 4cf401f..07efb35 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
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