tjh.dev / kernel
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
fork atom

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>

authored by

Borislav Petkov and committed by
Ingo Molnar aa042141 394db20c

+25 -25
+25 -25
arch/x86/kernel/verify_cpu.S
··· 48 48 pushfl 49 49 popl %eax 50 50 cmpl %eax,%ebx 51 - jz verify_cpu_no_longmode # cpu has no cpuid 51 + jz .Lverify_cpu_no_longmode # cpu has no cpuid 52 52 #endif 53 53 54 54 movl $0x0,%eax # See if cpuid 1 is implemented 55 55 cpuid 56 56 cmpl $0x1,%eax 57 - jb verify_cpu_no_longmode # no cpuid 1 57 + jb .Lverify_cpu_no_longmode # no cpuid 1 58 58 59 59 xor %di,%di 60 60 cmpl $0x68747541,%ebx # AuthenticAMD 61 - jnz verify_cpu_noamd 61 + jnz .Lverify_cpu_noamd 62 62 cmpl $0x69746e65,%edx 63 - jnz verify_cpu_noamd 63 + jnz .Lverify_cpu_noamd 64 64 cmpl $0x444d4163,%ecx 65 - jnz verify_cpu_noamd 65 + jnz .Lverify_cpu_noamd 66 66 mov $1,%di # cpu is from AMD 67 - jmp verify_cpu_check 67 + jmp .Lverify_cpu_check 68 68 69 - verify_cpu_noamd: 69 + .Lverify_cpu_noamd: 70 70 cmpl $0x756e6547,%ebx # GenuineIntel? 71 - jnz verify_cpu_check 71 + jnz .Lverify_cpu_check 72 72 cmpl $0x49656e69,%edx 73 - jnz verify_cpu_check 73 + jnz .Lverify_cpu_check 74 74 cmpl $0x6c65746e,%ecx 75 - jnz verify_cpu_check 75 + jnz .Lverify_cpu_check 76 76 77 77 # only call IA32_MISC_ENABLE when: 78 78 # family > 6 || (family == 6 && model >= 0xd) ··· 83 83 andl $0x0ff00f00, %eax # mask family and extended family 84 84 shrl $8, %eax 85 85 cmpl $6, %eax 86 - ja verify_cpu_clear_xd # family > 6, ok 87 - jb verify_cpu_check # family < 6, skip 86 + ja .Lverify_cpu_clear_xd # family > 6, ok 87 + jb .Lverify_cpu_check # family < 6, skip 88 88 89 89 andl $0x000f00f0, %ecx # mask model and extended model 90 90 shrl $4, %ecx 91 91 cmpl $0xd, %ecx 92 - jb verify_cpu_check # family == 6, model < 0xd, skip 92 + jb .Lverify_cpu_check # family == 6, model < 0xd, skip 93 93 94 - verify_cpu_clear_xd: 94 + .Lverify_cpu_clear_xd: 95 95 movl $MSR_IA32_MISC_ENABLE, %ecx 96 96 rdmsr 97 97 btrl $2, %edx # clear MSR_IA32_MISC_ENABLE_XD_DISABLE 98 - jnc verify_cpu_check # only write MSR if bit was changed 98 + jnc .Lverify_cpu_check # only write MSR if bit was changed 99 99 wrmsr 100 100 101 - verify_cpu_check: 101 + .Lverify_cpu_check: 102 102 movl $0x1,%eax # Does the cpu have what it takes 103 103 cpuid 104 104 andl $REQUIRED_MASK0,%edx 105 105 xorl $REQUIRED_MASK0,%edx 106 - jnz verify_cpu_no_longmode 106 + jnz .Lverify_cpu_no_longmode 107 107 108 108 movl $0x80000000,%eax # See if extended cpuid is implemented 109 109 cpuid 110 110 cmpl $0x80000001,%eax 111 - jb verify_cpu_no_longmode # no extended cpuid 111 + jb .Lverify_cpu_no_longmode # no extended cpuid 112 112 113 113 movl $0x80000001,%eax # Does the cpu have what it takes 114 114 cpuid 115 115 andl $REQUIRED_MASK1,%edx 116 116 xorl $REQUIRED_MASK1,%edx 117 - jnz verify_cpu_no_longmode 117 + jnz .Lverify_cpu_no_longmode 118 118 119 - verify_cpu_sse_test: 119 + .Lverify_cpu_sse_test: 120 120 movl $1,%eax 121 121 cpuid 122 122 andl $SSE_MASK,%edx 123 123 cmpl $SSE_MASK,%edx 124 - je verify_cpu_sse_ok 124 + je .Lverify_cpu_sse_ok 125 125 test %di,%di 126 - jz verify_cpu_no_longmode # only try to force SSE on AMD 126 + jz .Lverify_cpu_no_longmode # only try to force SSE on AMD 127 127 movl $MSR_K7_HWCR,%ecx 128 128 rdmsr 129 129 btr $15,%eax # enable SSE 130 130 wrmsr 131 131 xor %di,%di # don't loop 132 - jmp verify_cpu_sse_test # try again 132 + jmp .Lverify_cpu_sse_test # try again 133 133 134 - verify_cpu_no_longmode: 134 + .Lverify_cpu_no_longmode: 135 135 popf # Restore caller passed flags 136 136 movl $1,%eax 137 137 ret 138 - verify_cpu_sse_ok: 138 + .Lverify_cpu_sse_ok: 139 139 popf # Restore caller passed flags 140 140 xorl %eax, %eax 141 141 ret