| simon.hosie | 953b1c1 | 2016-04-06 14:02:26 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #include <stdlib.h> |
| 12 | #include <string.h> |
| 13 | #include <features.h> |
| 14 | #if __GLIBC_PREREQ(2, 16) |
| 15 | #include <sys/auxv.h> |
| 16 | #else |
| 17 | #include <fcntl.h> |
| 18 | #include <unistd.h> |
| 19 | #include <errno.h> |
| 20 | #include <link.h> |
| 21 | #endif |
| 22 | #include "webrtc/system_wrappers/include/cpu_features_wrapper.h" |
| 23 | |
| 24 | #if defined(WEBRTC_ARCH_ARM_FAMILY) |
| 25 | #include <asm/hwcap.h> |
| 26 | |
| 27 | uint64_t WebRtc_GetCPUFeaturesARM(void) { |
| 28 | uint64_t result = 0; |
| 29 | int architecture = 0; |
| 30 | unsigned long hwcap = 0; |
| 31 | const char* platform = NULL; |
| 32 | #if __GLIBC_PREREQ(2, 16) |
| 33 | hwcap = getauxval(AT_HWCAP); |
| 34 | platform = (const char*)getauxval(AT_PLATFORM); |
| 35 | #else |
| 36 | ElfW(auxv_t) auxv; |
| 37 | int fd = open("/proc/self/auxv", O_RDONLY); |
| 38 | if (fd >= 0) { |
| 39 | while (hwcap == 0 || platform == NULL) { |
| 40 | if (read(fd, &auxv, sizeof(auxv)) < (ssize_t)sizeof(auxv)) { |
| 41 | if (errno == EINTR) |
| 42 | continue; |
| 43 | break; |
| 44 | } |
| 45 | switch (auxv.a_type) { |
| 46 | case AT_HWCAP: |
| 47 | hwcap = auxv.a_un.a_val; |
| 48 | break; |
| 49 | case AT_PLATFORM: |
| 50 | platform = (const char*)auxv.a_un.a_val; |
| 51 | break; |
| 52 | } |
| 53 | } |
| 54 | close(fd); |
| 55 | } |
| 56 | #endif // __GLIBC_PREREQ(2,16) |
| 57 | #if defined(__aarch64__) |
| 58 | architecture = 8; |
| 59 | if ((hwcap & HWCAP_FP) != 0) |
| 60 | result |= kCPUFeatureVFPv3; |
| 61 | if ((hwcap & HWCAP_ASIMD) != 0) |
| 62 | result |= kCPUFeatureNEON; |
| 63 | #else |
| 64 | if (platform != NULL) { |
| 65 | /* expect a string in the form "v6l" or "v7l", etc. |
| 66 | */ |
| 67 | if (platform[0] == 'v' && '0' <= platform[1] && platform[1] <= '9' && |
| 68 | (platform[2] == 'l' || platform[2] == 'b')) { |
| 69 | architecture = platform[1] - '0'; |
| 70 | } |
| 71 | } |
| 72 | if ((hwcap & HWCAP_VFPv3) != 0) |
| 73 | result |= kCPUFeatureVFPv3; |
| 74 | if ((hwcap & HWCAP_NEON) != 0) |
| 75 | result |= kCPUFeatureNEON; |
| 76 | #endif |
| 77 | if (architecture >= 7) |
| 78 | result |= kCPUFeatureARMv7; |
| 79 | if (architecture >= 6) |
| 80 | result |= kCPUFeatureLDREXSTREX; |
| 81 | return result; |
| 82 | } |
| 83 | #endif // WEBRTC_ARCH_ARM_FAMILY |