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review.evervolv.com / android_kernel_htc_msm8960 / cb15dff4795932b98459da13dd3dd3693c6dd104 / . / arch / x86 / kernel / verify_cpu.S
blob: b9242bacbe59a2c02baee2e0d89fe8247b13106b [file] [log] [blame]
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]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)
Kees Cookae847392010-11-10 10:35:52 -0800[diff] [blame]10 * Copyright (c) 2010 Kees Cook (kees.cook@canonical.com)
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]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.
Kees Cookae847392010-11-10 10:35:52 -0800[diff] [blame]18 * This file is expected to run in 32bit code. Currently:
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]19 *
Kees Cook79250af2010-11-16 10:10:04 -0800[diff] [blame]20 * arch/x86/boot/compressed/head_64.S: Boot cpu verification
Lucas De Marchi0d2eb442011-03-17 16:24:16 -0300[diff] [blame]21 * arch/x86/kernel/trampoline_64.S: secondary processor verification
Kees Cook79250af2010-11-16 10:10:04 -0800[diff] [blame]22 * arch/x86/kernel/head_32.S: processor startup
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]23 *
Kees Cookae847392010-11-10 10:35:52 -0800[diff] [blame]24 * verify_cpu, returns the status of longmode and SSE in register %eax.
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]25 * 0: Success 1: Failure
26 *
Kees Cookae847392010-11-10 10:35:52 -0800[diff] [blame]27 * On Intel, the XD_DISABLE flag will be cleared as a side-effect.
28 *
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]29 * The caller needs to check for the error code and take the action
30 * appropriately. Either display a message or halt.
31 */
32
Andi Kleen72b1b1d2007-05-02 19:27:20 +0200[diff] [blame]33#include <asm/cpufeature.h>
Brian Gerstcfaa71e2010-07-17 09:03:27 -0400[diff] [blame]34#include <asm/msr-index.h>
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]35
Andi Kleen72b1b1d2007-05-02 19:27:20 +0200[diff] [blame]36verify_cpu:
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]37 pushfl # Save caller passed flags
38 pushl $0 # Kill any dangerous flags
39 popfl
40
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]41 pushfl # standard way to check for cpuid
42 popl %eax
43 movl %eax,%ebx
44 xorl $0x200000,%eax
45 pushl %eax
46 popfl
47 pushfl
48 popl %eax
49 cmpl %eax,%ebx
50 jz verify_cpu_no_longmode # cpu has no cpuid
51
52 movl $0x0,%eax # See if cpuid 1 is implemented
53 cpuid
54 cmpl $0x1,%eax
55 jb verify_cpu_no_longmode # no cpuid 1
56
57 xor %di,%di
58 cmpl $0x68747541,%ebx # AuthenticAMD
59 jnz verify_cpu_noamd
60 cmpl $0x69746e65,%edx
61 jnz verify_cpu_noamd
62 cmpl $0x444d4163,%ecx
63 jnz verify_cpu_noamd
64 mov $1,%di # cpu is from AMD
Kees Cookae847392010-11-10 10:35:52 -0800[diff] [blame]65 jmp verify_cpu_check
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]66
67verify_cpu_noamd:
Kees Cookae847392010-11-10 10:35:52 -0800[diff] [blame]68 cmpl $0x756e6547,%ebx # GenuineIntel?
69 jnz verify_cpu_check
70 cmpl $0x49656e69,%edx
71 jnz verify_cpu_check
72 cmpl $0x6c65746e,%ecx
73 jnz verify_cpu_check
74
75 # only call IA32_MISC_ENABLE when:
76 # family > 6 || (family == 6 && model >= 0xd)
77 movl $0x1, %eax # check CPU family and model
78 cpuid
79 movl %eax, %ecx
80
81 andl $0x0ff00f00, %eax # mask family and extended family
82 shrl $8, %eax
83 cmpl $6, %eax
84 ja verify_cpu_clear_xd # family > 6, ok
85 jb verify_cpu_check # family < 6, skip
86
87 andl $0x000f00f0, %ecx # mask model and extended model
88 shrl $4, %ecx
89 cmpl $0xd, %ecx
90 jb verify_cpu_check # family == 6, model < 0xd, skip
91
92verify_cpu_clear_xd:
93 movl $MSR_IA32_MISC_ENABLE, %ecx
94 rdmsr
95 btrl $2, %edx # clear MSR_IA32_MISC_ENABLE_XD_DISABLE
96 jnc verify_cpu_check # only write MSR if bit was changed
97 wrmsr
98
99verify_cpu_check:
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]100 movl $0x1,%eax # Does the cpu have what it takes
101 cpuid
H. Peter Anvinec481532007-07-11 12:18:29 -0700[diff] [blame]102 andl $REQUIRED_MASK0,%edx
103 xorl $REQUIRED_MASK0,%edx
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]104 jnz verify_cpu_no_longmode
105
106 movl $0x80000000,%eax # See if extended cpuid is implemented
107 cpuid
108 cmpl $0x80000001,%eax
109 jb verify_cpu_no_longmode # no extended cpuid
110
111 movl $0x80000001,%eax # Does the cpu have what it takes
112 cpuid
H. Peter Anvinec481532007-07-11 12:18:29 -0700[diff] [blame]113 andl $REQUIRED_MASK1,%edx
114 xorl $REQUIRED_MASK1,%edx
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]115 jnz verify_cpu_no_longmode
116
117verify_cpu_sse_test:
118 movl $1,%eax
119 cpuid
120 andl $SSE_MASK,%edx
121 cmpl $SSE_MASK,%edx
122 je verify_cpu_sse_ok
123 test %di,%di
124 jz verify_cpu_no_longmode # only try to force SSE on AMD
Brian Gerstcfaa71e2010-07-17 09:03:27 -0400[diff] [blame]125 movl $MSR_K7_HWCR,%ecx
Vivek Goyala4831e02007-05-02 19:27:08 +0200[diff] [blame]126 rdmsr
127 btr $15,%eax # enable SSE
128 wrmsr
129 xor %di,%di # don't loop
130 jmp verify_cpu_sse_test # try again
131
132verify_cpu_no_longmode:
133 popfl # Restore caller passed flags
134 movl $1,%eax
135 ret
136verify_cpu_sse_ok:
137 popfl # Restore caller passed flags
138 xorl %eax, %eax
139 ret