Commit | Line | Data |
---|---|---|
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) | |
10 | * | |
11 | * This source code is licensed under the GNU General Public License, | |
12 | * Version 2. See the file COPYING for more details. | |
13 | * | |
14 | * This is a common code for verification whether CPU supports | |
15 | * long mode and SSE or not. It is not called directly instead this | |
16 | * file is included at various places and compiled in that context. | |
17 | * Following are the current usage. | |
18 | * | |
19 | * This file is included by both 16bit and 32bit code. | |
20 | * | |
21 | * arch/x86_64/boot/setup.S : Boot cpu verification (16bit) | |
22 | * arch/x86_64/boot/compressed/head.S: Boot cpu verification (32bit) | |
23 | * arch/x86_64/kernel/trampoline.S: secondary processor verfication (16bit) | |
24 | * arch/x86_64/kernel/acpi/wakeup.S:Verfication at resume (16bit) | |
25 | * | |
26 | * verify_cpu, returns the status of cpu check in register %eax. | |
27 | * 0: Success 1: Failure | |
28 | * | |
29 | * The caller needs to check for the error code and take the action | |
30 | * appropriately. Either display a message or halt. | |
31 | */ | |
32 | ||
72b1b1d0 | 33 | #include <asm/cpufeature.h> |
a4831e08 | 34 | |
72b1b1d0 | 35 | verify_cpu: |
a4831e08 VG |
36 | pushfl # Save caller passed flags |
37 | pushl $0 # Kill any dangerous flags | |
38 | popfl | |
39 | ||
a4831e08 VG |
40 | pushfl # standard way to check for cpuid |
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 verify_cpu_no_longmode # cpu has no cpuid | |
50 | ||
51 | movl $0x0,%eax # See if cpuid 1 is implemented | |
52 | cpuid | |
53 | cmpl $0x1,%eax | |
54 | jb verify_cpu_no_longmode # no cpuid 1 | |
55 | ||
56 | xor %di,%di | |
57 | cmpl $0x68747541,%ebx # AuthenticAMD | |
58 | jnz verify_cpu_noamd | |
59 | cmpl $0x69746e65,%edx | |
60 | jnz verify_cpu_noamd | |
61 | cmpl $0x444d4163,%ecx | |
62 | jnz verify_cpu_noamd | |
63 | mov $1,%di # cpu is from AMD | |
64 | ||
65 | verify_cpu_noamd: | |
66 | movl $0x1,%eax # Does the cpu have what it takes | |
67 | cpuid | |
ec481536 PA |
68 | andl $REQUIRED_MASK0,%edx |
69 | xorl $REQUIRED_MASK0,%edx | |
a4831e08 VG |
70 | jnz verify_cpu_no_longmode |
71 | ||
72 | movl $0x80000000,%eax # See if extended cpuid is implemented | |
73 | cpuid | |
74 | cmpl $0x80000001,%eax | |
75 | jb verify_cpu_no_longmode # no extended cpuid | |
76 | ||
77 | movl $0x80000001,%eax # Does the cpu have what it takes | |
78 | cpuid | |
ec481536 PA |
79 | andl $REQUIRED_MASK1,%edx |
80 | xorl $REQUIRED_MASK1,%edx | |
a4831e08 VG |
81 | jnz verify_cpu_no_longmode |
82 | ||
83 | verify_cpu_sse_test: | |
84 | movl $1,%eax | |
85 | cpuid | |
86 | andl $SSE_MASK,%edx | |
87 | cmpl $SSE_MASK,%edx | |
88 | je verify_cpu_sse_ok | |
89 | test %di,%di | |
90 | jz verify_cpu_no_longmode # only try to force SSE on AMD | |
91 | movl $0xc0010015,%ecx # HWCR | |
92 | rdmsr | |
93 | btr $15,%eax # enable SSE | |
94 | wrmsr | |
95 | xor %di,%di # don't loop | |
96 | jmp verify_cpu_sse_test # try again | |
97 | ||
98 | verify_cpu_no_longmode: | |
99 | popfl # Restore caller passed flags | |
100 | movl $1,%eax | |
101 | ret | |
102 | verify_cpu_sse_ok: | |
103 | popfl # Restore caller passed flags | |
104 | xorl %eax, %eax | |
105 | ret |