FFmpeg
cpu.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include "libavutil/cpu.h"
20 #include "libavutil/cpu_internal.h"
21 #include "config.h"
22 
23 #define CORE_FLAG(f) \
24  (AV_CPU_FLAG_ ## f * (HAVE_ ## f ## _EXTERNAL || HAVE_ ## f ## _INLINE))
25 
26 #define CORE_CPU_FLAGS \
27  (CORE_FLAG(ARMV5TE) | \
28  CORE_FLAG(ARMV6) | \
29  CORE_FLAG(ARMV6T2) | \
30  CORE_FLAG(VFP) | \
31  CORE_FLAG(VFPV3) | \
32  CORE_FLAG(NEON))
33 
34 #if defined __linux__ || defined __ANDROID__
35 
36 #include <stdint.h>
37 #include <stdio.h>
38 #include <string.h>
39 #include "libavutil/avstring.h"
40 
41 #if HAVE_GETAUXVAL
42 #include <sys/auxv.h>
43 #endif
44 
45 #define AT_HWCAP 16
46 
47 /* Relevant HWCAP values from kernel headers */
48 #define HWCAP_VFP (1 << 6)
49 #define HWCAP_EDSP (1 << 7)
50 #define HWCAP_THUMBEE (1 << 11)
51 #define HWCAP_NEON (1 << 12)
52 #define HWCAP_VFPv3 (1 << 13)
53 #define HWCAP_TLS (1 << 15)
54 
55 static int get_auxval(uint32_t *hwcap)
56 {
57 #if HAVE_GETAUXVAL
58  unsigned long ret = ff_getauxval(AT_HWCAP);
59  if (ret == 0)
60  return -1;
61  *hwcap = ret;
62  return 0;
63 #else
64  return -1;
65 #endif
66 }
67 
68 static int get_hwcap(uint32_t *hwcap)
69 {
70  struct { uint32_t a_type; uint32_t a_val; } auxv;
71  FILE *f = fopen("/proc/self/auxv", "r");
72  int err = -1;
73 
74  if (!f)
75  return -1;
76 
77  while (fread(&auxv, sizeof(auxv), 1, f) > 0) {
78  if (auxv.a_type == AT_HWCAP) {
79  *hwcap = auxv.a_val;
80  err = 0;
81  break;
82  }
83  }
84 
85  fclose(f);
86  return err;
87 }
88 
89 static int get_cpuinfo(uint32_t *hwcap)
90 {
91  FILE *f = fopen("/proc/cpuinfo", "r");
92  char buf[200];
93 
94  if (!f)
95  return -1;
96 
97  *hwcap = 0;
98  while (fgets(buf, sizeof(buf), f)) {
99  if (av_strstart(buf, "Features", NULL)) {
100  if (strstr(buf, " edsp "))
101  *hwcap |= HWCAP_EDSP;
102  if (strstr(buf, " tls "))
103  *hwcap |= HWCAP_TLS;
104  if (strstr(buf, " thumbee "))
105  *hwcap |= HWCAP_THUMBEE;
106  if (strstr(buf, " vfp "))
107  *hwcap |= HWCAP_VFP;
108  if (strstr(buf, " vfpv3 "))
109  *hwcap |= HWCAP_VFPv3;
110  if (strstr(buf, " neon ") || strstr(buf, " asimd "))
111  *hwcap |= HWCAP_NEON;
112  if (strstr(buf, " fp ")) // Listed on 64 bit ARMv8 kernels
113  *hwcap |= HWCAP_VFP | HWCAP_VFPv3;
114  break;
115  }
116  }
117  fclose(f);
118  return 0;
119 }
120 
121 int ff_get_cpu_flags_arm(void)
122 {
123  int flags = CORE_CPU_FLAGS;
124  uint32_t hwcap;
125 
126  if (get_auxval(&hwcap) < 0)
127  if (get_hwcap(&hwcap) < 0)
128  if (get_cpuinfo(&hwcap) < 0)
129  return flags;
130 
131 #define check_cap(cap, flag) do { \
132  if (hwcap & HWCAP_ ## cap) \
133  flags |= AV_CPU_FLAG_ ## flag; \
134  } while (0)
135 
136  /* No flags explicitly indicate v6 or v6T2 so check others which
137  imply support. */
138  check_cap(EDSP, ARMV5TE);
139  check_cap(TLS, ARMV6);
140  check_cap(THUMBEE, ARMV6T2);
141  check_cap(VFP, VFP);
142  check_cap(VFPv3, VFPV3);
143  check_cap(NEON, NEON);
144 
145  /* The v6 checks above are not reliable so let higher flags
146  trickle down. */
150  /* Some functions use the 'setend' instruction which is deprecated on ARMv8
151  * and serializing on some ARMv7 cores. This ensures such functions
152  * are only enabled on ARMv6. */
154 
157 
158  /* set the virtual VFPv2 vector mode flag */
161 
162  return flags;
163 }
164 
165 #else
166 
168 {
169  return AV_CPU_FLAG_ARMV5TE * HAVE_ARMV5TE |
170  AV_CPU_FLAG_ARMV6 * HAVE_ARMV6 |
171  AV_CPU_FLAG_ARMV6T2 * HAVE_ARMV6T2 |
172  AV_CPU_FLAG_VFP * HAVE_VFP |
173  AV_CPU_FLAG_VFPV3 * HAVE_VFPV3 |
174  AV_CPU_FLAG_NEON * HAVE_NEON |
175  AV_CPU_FLAG_SETEND * !(HAVE_NEON | HAVE_VFPV3);
176 }
177 
178 #endif
179 
181 {
182  int flags = av_get_cpu_flags();
183 
184  if (flags & AV_CPU_FLAG_NEON)
185  return 16;
186 
187  return 8;
188 }
AV_CPU_FLAG_VFP
#define AV_CPU_FLAG_VFP
Definition: cpu.h:68
ff_get_cpu_flags_arm
int ff_get_cpu_flags_arm(void)
Definition: cpu.c:167
av_get_cpu_flags
int av_get_cpu_flags(void)
Return the flags which specify extensions supported by the CPU.
Definition: cpu.c:107
cpu_internal.h
AV_CPU_FLAG_ARMV6
#define AV_CPU_FLAG_ARMV6
Definition: cpu.h:66
ff_getauxval
unsigned long ff_getauxval(unsigned long type)
Definition: cpu.c:295
NULL
#define NULL
Definition: coverity.c:32
f
f
Definition: af_crystalizer.c:122
AV_CPU_FLAG_SETEND
#define AV_CPU_FLAG_SETEND
Definition: cpu.h:77
cpu.h
AV_CPU_FLAG_NEON
#define AV_CPU_FLAG_NEON
Definition: cpu.h:70
av_strstart
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:36
ret
ret
Definition: filter_design.txt:187
AV_CPU_FLAG_VFPV3
#define AV_CPU_FLAG_VFPV3
Definition: cpu.h:69
ff_get_cpu_max_align_arm
size_t ff_get_cpu_max_align_arm(void)
Definition: cpu.c:180
AV_CPU_FLAG_ARMV5TE
#define AV_CPU_FLAG_ARMV5TE
Definition: cpu.h:65
AV_CPU_FLAG_VFP_VM
#define AV_CPU_FLAG_VFP_VM
VFPv2 vector mode, deprecated in ARMv7-A and unavailable in various CPUs implementations.
Definition: cpu.h:72
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:482
avstring.h
CORE_CPU_FLAGS
#define CORE_CPU_FLAGS
Definition: cpu.c:26
AV_CPU_FLAG_ARMV6T2
#define AV_CPU_FLAG_ARMV6T2
Definition: cpu.h:67