From aa0421410fc540832f0fd267ff0f2657c3276053 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sun, 3 Jan 2016 23:38:53 +0100 Subject: [PATCH] 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 Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Quentin Casasnovas Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1451860733-21163-1-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- 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 -- 2.30.2