1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 *
4 * verify_cpu.S - Code for cpu long mode
5 * code has been borrowed from boot/setup
6 * Andi Kleen.
7 *
8 * Copyright (c) 2007 Andi Kleen (ak@sus
9 * Copyright (c) 2007 Eric Biederman (eb
10 * Copyright (c) 2007 Vivek Goyal (vgoya
11 * Copyright (c) 2010 Kees Cook (kees.co
12 *
13 * This is a common code for verification
14 * long mode and SSE or not. It is not ca
15 * file is included at various places and
16 * This file is expected to run in 32bit
17 *
18 * arch/x86/boot/compressed/head_64.S: Bo
19 * arch/x86/kernel/trampoline_64.S: secon
20 * arch/x86/kernel/head_32.S: processor s
21 *
22 * verify_cpu, returns the status of long
23 * 0: Success 1: Failure
24 *
25 * On Intel, the XD_DISABLE flag will be
26 *
27 * The caller needs to check for the erro
28 * appropriately. Either display a messag
29 */
30
31 #include <asm/cpufeatures.h>
32 #include <asm/msr-index.h>
33
34 SYM_FUNC_START_LOCAL(verify_cpu)
35 pushf # Save
36 push $0 # Kill
37 popf
38
39 #ifndef __x86_64__
40 pushfl # stan
41 popl %eax
42 movl %eax,%ebx
43 xorl $0x200000,%eax
44 pushl %eax
45 popfl
46 pushfl
47 popl %eax
48 cmpl %eax,%ebx
49 jz .Lverify_cpu_no_longmode
50 #endif
51
52 movl $0x0,%eax # See
53 cpuid
54 cmpl $0x1,%eax
55 jb .Lverify_cpu_no_longmode
56
57 xor %di,%di
58 cmpl $0x68747541,%ebx # Auth
59 jnz .Lverify_cpu_noamd
60 cmpl $0x69746e65,%edx
61 jnz .Lverify_cpu_noamd
62 cmpl $0x444d4163,%ecx
63 jnz .Lverify_cpu_noamd
64 mov $1,%di # cpu
65 jmp .Lverify_cpu_check
66
67 .Lverify_cpu_noamd:
68 cmpl $0x756e6547,%ebx # Genu
69 jnz .Lverify_cpu_check
70 cmpl $0x49656e69,%edx
71 jnz .Lverify_cpu_check
72 cmpl $0x6c65746e,%ecx
73 jnz .Lverify_cpu_check
74
75 # only call IA32_MISC_ENABLE when:
76 # family > 6 || (family == 6 && model
77 movl $0x1, %eax # chec
78 cpuid
79 movl %eax, %ecx
80
81 andl $0x0ff00f00, %eax # mask
82 shrl $8, %eax
83 cmpl $6, %eax
84 ja .Lverify_cpu_clear_xd # fami
85 jb .Lverify_cpu_check # fami
86
87 andl $0x000f00f0, %ecx # mask
88 shrl $4, %ecx
89 cmpl $0xd, %ecx
90 jb .Lverify_cpu_check # fami
91
92 .Lverify_cpu_clear_xd:
93 movl $MSR_IA32_MISC_ENABLE, %ecx
94 rdmsr
95 btrl $2, %edx # clea
96 jnc .Lverify_cpu_check # only
97 wrmsr
98
99 .Lverify_cpu_check:
100 movl $0x1,%eax # Does
101 cpuid
102 andl $REQUIRED_MASK0,%edx
103 xorl $REQUIRED_MASK0,%edx
104 jnz .Lverify_cpu_no_longmode
105
106 movl $0x80000000,%eax # See
107 cpuid
108 cmpl $0x80000001,%eax
109 jb .Lverify_cpu_no_longmode
110
111 movl $0x80000001,%eax # Does
112 cpuid
113 andl $REQUIRED_MASK1,%edx
114 xorl $REQUIRED_MASK1,%edx
115 jnz .Lverify_cpu_no_longmode
116
117 .Lverify_cpu_sse_test:
118 movl $1,%eax
119 cpuid
120 andl $SSE_MASK,%edx
121 cmpl $SSE_MASK,%edx
122 je .Lverify_cpu_sse_ok
123 test %di,%di
124 jz .Lverify_cpu_no_longmode
125 movl $MSR_K7_HWCR,%ecx
126 rdmsr
127 btr $15,%eax # enab
128 wrmsr
129 xor %di,%di # don'
130 jmp .Lverify_cpu_sse_test # try
131
132 .Lverify_cpu_no_longmode:
133 popf # Rest
134 movl $1,%eax
135 RET
136 .Lverify_cpu_sse_ok:
137 popf # Rest
138 xorl %eax, %eax
139 RET
140 SYM_FUNC_END(verify_cpu)
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.