Merge "Fix cpufeatures to not parse /proc/self/auxv"
diff --git a/sources/android/cpufeatures/cpu-features.c b/sources/android/cpufeatures/cpu-features.c
index 5b0a9d9..119c2ac 100644
--- a/sources/android/cpufeatures/cpu-features.c
+++ b/sources/android/cpufeatures/cpu-features.c
@@ -123,22 +123,22 @@
fd = open(pathname, O_RDONLY);
if (fd < 0) {
- D("Can't open %s: %s\n", pathname, strerror(errno));
- return -1;
+ D("Can't open %s: %s\n", pathname, strerror(errno));
+ return -1;
}
for (;;) {
- int ret = read(fd, buffer, sizeof buffer);
- if (ret < 0) {
- if (errno == EINTR)
- continue;
- D("Error while reading %s: %s\n", pathname, strerror(errno));
- break;
- }
- if (ret == 0)
- break;
+ int ret = read(fd, buffer, sizeof buffer);
+ if (ret < 0) {
+ if (errno == EINTR)
+ continue;
+ D("Error while reading %s: %s\n", pathname, strerror(errno));
+ break;
+ }
+ if (ret == 0)
+ break;
- result += ret;
+ result += ret;
}
close(fd);
return result;
@@ -185,10 +185,10 @@
* Return NULL if not found
*/
static char*
-extract_cpuinfo_field(char* buffer, int buflen, const char* field)
+extract_cpuinfo_field(const char* buffer, int buflen, const char* field)
{
int fieldlen = strlen(field);
- char* bufend = buffer + buflen;
+ const char* bufend = buffer + buflen;
char* result = NULL;
int len, ignore;
const char *p, *q;
@@ -421,11 +421,22 @@
#define AT_HWCAP 16
-/* Read the ELF HWCAP flags by parsing /proc/self/auxv
+#if defined(__arm__)
+/* Compute the ELF HWCAP flags.
*/
static uint32_t
-get_elf_hwcap(void)
+get_elf_hwcap(const char* cpuinfo, int cpuinfo_len)
{
+ /* IMPORTANT:
+ * Accessing /proc/self/auxv doesn't work anymore on all
+ * platform versions. More specifically, when running inside
+ * a regular application process, most of /proc/self/ will be
+ * non-readable, including /proc/self/auxv. This doesn't
+ * happen however if the application is debuggable, or when
+ * running under the "shell" UID, which is why this was not
+ * detected appropriately.
+ */
+#if 0
uint32_t result = 0;
const char filepath[] = "/proc/self/auxv";
int fd = open(filepath, O_RDONLY);
@@ -454,7 +465,40 @@
}
close(fd);
return result;
+#else
+ // Recreate ELF hwcaps by parsing /proc/cpuinfo Features tag.
+ uint32_t hwcaps = 0;
+
+ char* cpuFeatures = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "Features");
+
+ if (cpuFeatures != NULL) {
+ D("Found cpuFeatures = '%s'\n", cpuFeatures);
+
+ if (has_list_item(cpuFeatures, "vfp"))
+ hwcaps |= HWCAP_VFP;
+ if (has_list_item(cpuFeatures, "vfpv3"))
+ hwcaps |= HWCAP_VFPv3;
+ if (has_list_item(cpuFeatures, "vfpv3d16"))
+ hwcaps |= HWCAP_VFPv3D16;
+ if (has_list_item(cpuFeatures, "vfpv4"))
+ hwcaps |= HWCAP_VFPv4;
+ if (has_list_item(cpuFeatures, "neon"))
+ hwcaps |= HWCAP_NEON;
+ if (has_list_item(cpuFeatures, "idiva"))
+ hwcaps |= HWCAP_IDIVA;
+ if (has_list_item(cpuFeatures, "idivt"))
+ hwcaps |= HWCAP_IDIVT;
+ if (has_list_item(cpuFeatures, "idiv"))
+ hwcaps |= HWCAP_IDIVA | HWCAP_IDIVT;
+ if (has_list_item(cpuFeatures, "iwmmxt"))
+ hwcaps |= HWCAP_IWMMXT;
+
+ free(cpuFeatures);
+ }
+ return hwcaps;
+#endif
}
+#endif /* __arm__ */
/* Return the number of cpus present on a given device.
*
@@ -601,7 +645,7 @@
}
/* Extract the list of CPU features from ELF hwcaps */
- uint32_t hwcaps = get_elf_hwcap();
+ uint32_t hwcaps = get_elf_hwcap(cpuinfo, cpuinfo_len);
if (hwcaps != 0) {
int has_vfp = (hwcaps & HWCAP_VFP);
@@ -618,9 +662,9 @@
// 'vfpv4' implies VFPv3|VFP_FMA|FP16
if (has_vfpv4)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3 |
- ANDROID_CPU_ARM_FEATURE_VFP_FP16 |
- ANDROID_CPU_ARM_FEATURE_VFP_FMA;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3 |
+ ANDROID_CPU_ARM_FEATURE_VFP_FP16 |
+ ANDROID_CPU_ARM_FEATURE_VFP_FMA;
// 'vfpv3' or 'vfpv3d16' imply VFPv3. Note that unlike GCC,
// a value of 'vfpv3' doesn't necessarily mean that the D32
@@ -628,42 +672,42 @@
// field that support D32 also support NEON, so this should
// not be a problem in practice.
if (has_vfpv3 || has_vfpv3d16)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
// 'vfp' is super ambiguous. Depending on the kernel, it can
// either mean VFPv2 or VFPv3. Make it depend on ARMv7.
if (has_vfp) {
if (g_cpuFeatures & ANDROID_CPU_ARM_FEATURE_ARMv7)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
else
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2;
}
// Neon implies VFPv3|D32, and if vfpv4 is detected, NEON_FMA
if (has_neon) {
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3 |
- ANDROID_CPU_ARM_FEATURE_NEON |
- ANDROID_CPU_ARM_FEATURE_VFP_D32;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3 |
+ ANDROID_CPU_ARM_FEATURE_NEON |
+ ANDROID_CPU_ARM_FEATURE_VFP_D32;
if (has_vfpv4)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON_FMA;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON_FMA;
}
// VFPv3 implies VFPv2 and ARMv7
if (g_cpuFeatures & ANDROID_CPU_ARM_FEATURE_VFPv3)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2 |
- ANDROID_CPU_ARM_FEATURE_ARMv7;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2 |
+ ANDROID_CPU_ARM_FEATURE_ARMv7;
// Note that some buggy kernels do not report these even when
// the CPU actually support the division instructions. However,
// assume that if 'vfpv4' is detected, then the CPU supports
// sdiv/udiv properly.
if (has_idiva || has_vfpv4)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_ARM;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_ARM;
if (has_idivt || has_vfpv4)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2;
if (has_iwmmxt)
- g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_iWMMXt;
+ g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_iWMMXt;
}
}
#endif /* __ARM_ARCH__ */
