1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build 386 || amd64
package cpu
const CacheLinePadSize = 64
// cpuid is implemented in cpu_x86.s.
func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
// xgetbv with ecx = 0 is implemented in cpu_x86.s.
func xgetbv() (eax, edx uint32)
// getGOAMD64level is implemented in cpu_x86.s. Returns number in [1,4].
func getGOAMD64level() int32
const (
// edx bits
cpuid_SSE2 = 1 << 26
// ecx bits
cpuid_SSE3 = 1 << 0
cpuid_PCLMULQDQ = 1 << 1
cpuid_SSSE3 = 1 << 9
cpuid_FMA = 1 << 12
cpuid_SSE41 = 1 << 19
cpuid_SSE42 = 1 << 20
cpuid_POPCNT = 1 << 23
cpuid_AES = 1 << 25
cpuid_OSXSAVE = 1 << 27
cpuid_AVX = 1 << 28
// ebx bits
cpuid_BMI1 = 1 << 3
cpuid_AVX2 = 1 << 5
cpuid_BMI2 = 1 << 8
cpuid_ERMS = 1 << 9
cpuid_AVX512F = 1 << 16
cpuid_ADX = 1 << 19
cpuid_SHA = 1 << 29
cpuid_AVX512BW = 1 << 30
cpuid_AVX512VL = 1 << 31
// edx bits for CPUID 0x80000001
cpuid_RDTSCP = 1 << 27
)
var maxExtendedFunctionInformation uint32
func doinit() {
options = []option{
{Name: "adx", Feature: &X86.HasADX},
{Name: "aes", Feature: &X86.HasAES},
{Name: "erms", Feature: &X86.HasERMS},
{Name: "pclmulqdq", Feature: &X86.HasPCLMULQDQ},
{Name: "rdtscp", Feature: &X86.HasRDTSCP},
{Name: "sha", Feature: &X86.HasSHA},
}
level := getGOAMD64level()
if level < 2 {
// These options are required at level 2. At lower levels
// they can be turned off.
options = append(options,
option{Name: "popcnt", Feature: &X86.HasPOPCNT},
option{Name: "sse3", Feature: &X86.HasSSE3},
option{Name: "sse41", Feature: &X86.HasSSE41},
option{Name: "sse42", Feature: &X86.HasSSE42},
option{Name: "ssse3", Feature: &X86.HasSSSE3})
}
if level < 3 {
// These options are required at level 3. At lower levels
// they can be turned off.
options = append(options,
option{Name: "avx", Feature: &X86.HasAVX},
option{Name: "avx2", Feature: &X86.HasAVX2},
option{Name: "bmi1", Feature: &X86.HasBMI1},
option{Name: "bmi2", Feature: &X86.HasBMI2},
option{Name: "fma", Feature: &X86.HasFMA})
}
if level < 4 {
// These options are required at level 4. At lower levels
// they can be turned off.
options = append(options,
option{Name: "avx512f", Feature: &X86.HasAVX512F},
option{Name: "avx512bw", Feature: &X86.HasAVX512BW},
option{Name: "avx512vl", Feature: &X86.HasAVX512VL},
)
}
maxID, _, _, _ := cpuid(0, 0)
if maxID < 1 {
return
}
maxExtendedFunctionInformation, _, _, _ = cpuid(0x80000000, 0)
_, _, ecx1, _ := cpuid(1, 0)
X86.HasSSE3 = isSet(ecx1, cpuid_SSE3)
X86.HasPCLMULQDQ = isSet(ecx1, cpuid_PCLMULQDQ)
X86.HasSSSE3 = isSet(ecx1, cpuid_SSSE3)
X86.HasSSE41 = isSet(ecx1, cpuid_SSE41)
X86.HasSSE42 = isSet(ecx1, cpuid_SSE42)
X86.HasPOPCNT = isSet(ecx1, cpuid_POPCNT)
X86.HasAES = isSet(ecx1, cpuid_AES)
// OSXSAVE can be false when using older Operating Systems
// or when explicitly disabled on newer Operating Systems by
// e.g. setting the xsavedisable boot option on Windows 10.
X86.HasOSXSAVE = isSet(ecx1, cpuid_OSXSAVE)
// The FMA instruction set extension only has VEX prefixed instructions.
// VEX prefixed instructions require OSXSAVE to be enabled.
// See Intel 64 and IA-32 Architecture Software Developer’s Manual Volume 2
// Section 2.4 "AVX and SSE Instruction Exception Specification"
X86.HasFMA = isSet(ecx1, cpuid_FMA) && X86.HasOSXSAVE
osSupportsAVX := false
osSupportsAVX512 := false
// For XGETBV, OSXSAVE bit is required and sufficient.
if X86.HasOSXSAVE {
eax, _ := xgetbv()
// Check if XMM and YMM registers have OS support.
osSupportsAVX = isSet(eax, 1<<1) && isSet(eax, 1<<2)
// AVX512 detection does not work on Darwin,
// see https://github.com/golang/go/issues/49233
//
// Check if opmask, ZMMhi256 and Hi16_ZMM have OS support.
osSupportsAVX512 = osSupportsAVX && isSet(eax, 1<<5) && isSet(eax, 1<<6) && isSet(eax, 1<<7)
}
X86.HasAVX = isSet(ecx1, cpuid_AVX) && osSupportsAVX
if maxID < 7 {
return
}
_, ebx7, _, _ := cpuid(7, 0)
X86.HasBMI1 = isSet(ebx7, cpuid_BMI1)
X86.HasAVX2 = isSet(ebx7, cpuid_AVX2) && osSupportsAVX
X86.HasBMI2 = isSet(ebx7, cpuid_BMI2)
X86.HasERMS = isSet(ebx7, cpuid_ERMS)
X86.HasADX = isSet(ebx7, cpuid_ADX)
X86.HasSHA = isSet(ebx7, cpuid_SHA)
X86.HasAVX512F = isSet(ebx7, cpuid_AVX512F) && osSupportsAVX512
if X86.HasAVX512F {
X86.HasAVX512BW = isSet(ebx7, cpuid_AVX512BW)
X86.HasAVX512VL = isSet(ebx7, cpuid_AVX512VL)
}
var maxExtendedInformation uint32
maxExtendedInformation, _, _, _ = cpuid(0x80000000, 0)
if maxExtendedInformation < 0x80000001 {
return
}
_, _, _, edxExt1 := cpuid(0x80000001, 0)
X86.HasRDTSCP = isSet(edxExt1, cpuid_RDTSCP)
}
func isSet(hwc uint32, value uint32) bool {
return hwc&value != 0
}
// Name returns the CPU name given by the vendor.
// If the CPU name can not be determined an
// empty string is returned.
func Name() string {
if maxExtendedFunctionInformation < 0x80000004 {
return ""
}
data := make([]byte, 0, 3*4*4)
var eax, ebx, ecx, edx uint32
eax, ebx, ecx, edx = cpuid(0x80000002, 0)
data = appendBytes(data, eax, ebx, ecx, edx)
eax, ebx, ecx, edx = cpuid(0x80000003, 0)
data = appendBytes(data, eax, ebx, ecx, edx)
eax, ebx, ecx, edx = cpuid(0x80000004, 0)
data = appendBytes(data, eax, ebx, ecx, edx)
// Trim leading spaces.
for len(data) > 0 && data[0] == ' ' {
data = data[1:]
}
// Trim tail after and including the first null byte.
for i, c := range data {
if c == '\x00' {
data = data[:i]
break
}
}
return string(data)
}
func appendBytes(b []byte, args ...uint32) []byte {
for _, arg := range args {
b = append(b,
byte((arg >> 0)),
byte((arg >> 8)),
byte((arg >> 16)),
byte((arg >> 24)))
}
return b
}
|
