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x86/cpu/AMD: Fix erratum 1076 (CPB bit)
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CommitLineData
a4831e08
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1/*
2 *
3 * verify_cpu.S - Code for cpu long mode and SSE verification. This
4 * code has been borrowed from boot/setup.S and was introduced by
5 * Andi Kleen.
6 *
7 * Copyright (c) 2007 Andi Kleen (ak@suse.de)
8 * Copyright (c) 2007 Eric Biederman (ebiederm@xmission.com)
9 * Copyright (c) 2007 Vivek Goyal (vgoyal@in.ibm.com)
ae84739c 10 * Copyright (c) 2010 Kees Cook (kees.cook@canonical.com)
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11 *
12 * This source code is licensed under the GNU General Public License,
13 * Version 2. See the file COPYING for more details.
14 *
15 * This is a common code for verification whether CPU supports
16 * long mode and SSE or not. It is not called directly instead this
17 * file is included at various places and compiled in that context.
ae84739c 18 * This file is expected to run in 32bit code. Currently:
a4831e08 19 *
79250af2 20 * arch/x86/boot/compressed/head_64.S: Boot cpu verification
0d2eb44f 21 * arch/x86/kernel/trampoline_64.S: secondary processor verification
79250af2 22 * arch/x86/kernel/head_32.S: processor startup
a4831e08 23 *
ae84739c 24 * verify_cpu, returns the status of longmode and SSE in register %eax.
a4831e08
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25 * 0: Success 1: Failure
26 *
ae84739c
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27 * On Intel, the XD_DISABLE flag will be cleared as a side-effect.
28 *
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29 * The caller needs to check for the error code and take the action
30 * appropriately. Either display a message or halt.
31 */
32
cd4d09ec 33#include <asm/cpufeatures.h>
cfaa71ee 34#include <asm/msr-index.h>
a4831e08 35
48a432c4 36ENTRY(verify_cpu)
04633df0
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37 pushf # Save caller passed flags
38 push $0 # Kill any dangerous flags
39 popf
a4831e08 40
04633df0 41#ifndef __x86_64__
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42 pushfl # standard way to check for cpuid
43 popl %eax
44 movl %eax,%ebx
45 xorl $0x200000,%eax
46 pushl %eax
47 popfl
48 pushfl
49 popl %eax
50 cmpl %eax,%ebx
aa042141 51 jz .Lverify_cpu_no_longmode # cpu has no cpuid
04633df0 52#endif
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53
54 movl $0x0,%eax # See if cpuid 1 is implemented
55 cpuid
56 cmpl $0x1,%eax
aa042141 57 jb .Lverify_cpu_no_longmode # no cpuid 1
a4831e08
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58
59 xor %di,%di
60 cmpl $0x68747541,%ebx # AuthenticAMD
aa042141 61 jnz .Lverify_cpu_noamd
a4831e08 62 cmpl $0x69746e65,%edx
aa042141 63 jnz .Lverify_cpu_noamd
a4831e08 64 cmpl $0x444d4163,%ecx
aa042141 65 jnz .Lverify_cpu_noamd
a4831e08 66 mov $1,%di # cpu is from AMD
aa042141 67 jmp .Lverify_cpu_check
a4831e08 68
aa042141 69.Lverify_cpu_noamd:
ae84739c 70 cmpl $0x756e6547,%ebx # GenuineIntel?
aa042141 71 jnz .Lverify_cpu_check
ae84739c 72 cmpl $0x49656e69,%edx
aa042141 73 jnz .Lverify_cpu_check
ae84739c 74 cmpl $0x6c65746e,%ecx
aa042141 75 jnz .Lverify_cpu_check
ae84739c
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76
77 # only call IA32_MISC_ENABLE when:
78 # family > 6 || (family == 6 && model >= 0xd)
79 movl $0x1, %eax # check CPU family and model
80 cpuid
81 movl %eax, %ecx
82
83 andl $0x0ff00f00, %eax # mask family and extended family
84 shrl $8, %eax
85 cmpl $6, %eax
aa042141
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86 ja .Lverify_cpu_clear_xd # family > 6, ok
87 jb .Lverify_cpu_check # family < 6, skip
ae84739c
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88
89 andl $0x000f00f0, %ecx # mask model and extended model
90 shrl $4, %ecx
91 cmpl $0xd, %ecx
aa042141 92 jb .Lverify_cpu_check # family == 6, model < 0xd, skip
ae84739c 93
aa042141 94.Lverify_cpu_clear_xd:
ae84739c
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95 movl $MSR_IA32_MISC_ENABLE, %ecx
96 rdmsr
97 btrl $2, %edx # clear MSR_IA32_MISC_ENABLE_XD_DISABLE
aa042141 98 jnc .Lverify_cpu_check # only write MSR if bit was changed
ae84739c
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99 wrmsr
100
aa042141 101.Lverify_cpu_check:
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102 movl $0x1,%eax # Does the cpu have what it takes
103 cpuid
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104 andl $REQUIRED_MASK0,%edx
105 xorl $REQUIRED_MASK0,%edx
aa042141 106 jnz .Lverify_cpu_no_longmode
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107
108 movl $0x80000000,%eax # See if extended cpuid is implemented
109 cpuid
110 cmpl $0x80000001,%eax
aa042141 111 jb .Lverify_cpu_no_longmode # no extended cpuid
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112
113 movl $0x80000001,%eax # Does the cpu have what it takes
114 cpuid
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115 andl $REQUIRED_MASK1,%edx
116 xorl $REQUIRED_MASK1,%edx
aa042141 117 jnz .Lverify_cpu_no_longmode
a4831e08 118
aa042141 119.Lverify_cpu_sse_test:
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120 movl $1,%eax
121 cpuid
122 andl $SSE_MASK,%edx
123 cmpl $SSE_MASK,%edx
aa042141 124 je .Lverify_cpu_sse_ok
a4831e08 125 test %di,%di
aa042141 126 jz .Lverify_cpu_no_longmode # only try to force SSE on AMD
cfaa71ee 127 movl $MSR_K7_HWCR,%ecx
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128 rdmsr
129 btr $15,%eax # enable SSE
130 wrmsr
131 xor %di,%di # don't loop
aa042141 132 jmp .Lverify_cpu_sse_test # try again
a4831e08 133
aa042141 134.Lverify_cpu_no_longmode:
04633df0 135 popf # Restore caller passed flags
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136 movl $1,%eax
137 ret
aa042141 138.Lverify_cpu_sse_ok:
04633df0 139 popf # Restore caller passed flags
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140 xorl %eax, %eax
141 ret
48a432c4 142ENDPROC(verify_cpu)