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a4831e08 VG |
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) |
a4831e08 VG |
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 VG |
25 | * 0: Success 1: Failure |
26 | * | |
ae84739c KC |
27 | * On Intel, the XD_DISABLE flag will be cleared as a side-effect. |
28 | * | |
a4831e08 VG |
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 | |
72b1b1d0 | 36 | verify_cpu: |
04633df0 BP |
37 | pushf # Save caller passed flags |
38 | push $0 # Kill any dangerous flags | |
39 | popf | |
a4831e08 | 40 | |
04633df0 | 41 | #ifndef __x86_64__ |
a4831e08 VG |
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 |
a4831e08 VG |
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 VG |
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 KC |
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 BP |
86 | ja .Lverify_cpu_clear_xd # family > 6, ok |
87 | jb .Lverify_cpu_check # family < 6, skip | |
ae84739c KC |
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 KC |
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 KC |
99 | wrmsr |
100 | ||
aa042141 | 101 | .Lverify_cpu_check: |
a4831e08 VG |
102 | movl $0x1,%eax # Does the cpu have what it takes |
103 | cpuid | |
ec481536 PA |
104 | andl $REQUIRED_MASK0,%edx |
105 | xorl $REQUIRED_MASK0,%edx | |
aa042141 | 106 | jnz .Lverify_cpu_no_longmode |
a4831e08 VG |
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 |
a4831e08 VG |
112 | |
113 | movl $0x80000001,%eax # Does the cpu have what it takes | |
114 | cpuid | |
ec481536 PA |
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: |
a4831e08 VG |
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 |
a4831e08 VG |
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 |
a4831e08 VG |
136 | movl $1,%eax |
137 | ret | |
aa042141 | 138 | .Lverify_cpu_sse_ok: |
04633df0 | 139 | popf # Restore caller passed flags |
a4831e08 VG |
140 | xorl %eax, %eax |
141 | ret |