/*
* Copyright (C) 2010 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/system_properties.h>
#include <machine/cpu-features.h>
#include <pthread.h>
#include "cpu-features.h"
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
static pthread_once_t g_once;
static AndroidCpuFamily g_cpuFamily;
static uint64_t g_cpuFeatures;
static const int android_cpufeatures_debug = 0;
#define D(...) \
do { \
if (android_cpufeatures_debug) { \
printf(__VA_ARGS__); fflush(stdout); \
} \
} while (0)
/* Read the content of /proc/cpuinfo into a user-provided buffer.
* Return the length of the data, or -1 on error. Does *not*
* zero-terminate the content. Will not read more
* than 'buffsize' bytes.
*/
static int
read_file(const char* pathname, char* buffer, size_t buffsize)
{
int fd, len;
fd = open(pathname, O_RDONLY);
if (fd < 0)
return -1;
do {
len = read(fd, buffer, buffsize);
} while (len < 0 && errno == EINTR);
close(fd);
return len;
}
/* Extract the content of a the first occurence of a given field in
* the content of /proc/cpuinfo and return it as a heap-allocated
* string that must be freed by the caller.
*
* Return NULL if not found
*/
static char*
extract_cpuinfo_field(char* buffer, int buflen, const char* field)
{
int fieldlen = strlen(field);
char* bufend = buffer + buflen;
char* result = NULL;
int len, ignore;
const char *p, *q;
/* Look for first field occurence, and ensures it starts the line.
*/
p = buffer;
bufend = buffer + buflen;
for (;;) {
p = memmem(p, bufend-p, field, fieldlen);
if (p == NULL)
goto EXIT;
if (p == buffer || p[-1] == '\n')
break;
p += fieldlen;
}
/* Skip to the first column followed by a space */
p += fieldlen;
p = memchr(p, ':', bufend-p);
if (p == NULL || p[1] != ' ')
goto EXIT;
/* Find the end of the line */
p += 2;
q = memchr(p, '\n', bufend-p);
if (q == NULL)
q = bufend;
/* Copy the line into a heap-allocated buffer */
len = q-p;
result = malloc(len+1);
if (result == NULL)
goto EXIT;
memcpy(result, p, len);
result[len] = '\0';
EXIT:
return result;
}
/* Checks that a space-separated list of items contains one given 'item'.
* Returns 1 if found, 0 otherwise.
*/
static int
has_list_item(const char* list, const char* item)
{
const char* p = list;
int itemlen = strlen(item);
if (list == NULL)
return 0;
while (*p) {
const char* q;
/* skip spaces */
while (*p == ' ' || *p == '\t')
p++;
/* find end of current list item */
q = p;
while (*q && *q != ' ' && *q != '\t')
q++;
if (itemlen == q-p && !memcmp(p, item, itemlen))
return 1;
/* skip to next item */
p = q;
}
return 0;
}
static void
android_cpuInit(void)
{
g_cpuFamily = ANDROID_CPU_FAMILY_UNKNOWN;
g_cpuFeatures = 0;
#ifdef __ARM_ARCH__
{
char cpuinfo[4096];
int cpuinfo_len = read_file("/proc/cpuinfo", cpuinfo, sizeof cpuinfo);
char* features = NULL;
char* architecture = NULL;
g_cpuFamily = ANDROID_CPU_FAMILY_ARM;
D("cpuinfo_len is (%d):\n%.*s\n", cpuinfo_len, cpuinfo_len, cpuinfo);
if (cpuinfo_len < 0) /* should not happen */ {
return;
}
/* Extract architecture from the "CPU Architecture" field,
* Which can be something like 5JTE, 7, or something else.
* We cannot rely on the 'Processor' field here.
*/
{
char* cpuArch = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "CPU architecture");
if (cpuArch != NULL) {
char* end;
long archNumber;
D("found cpuArch = '%s'\n", cpuArch);
/* read the initial decimal number, ignore the rest */
archNumber = strtol(cpuArch, &end, 10);
/* Here we assume that ARMv8 will be upwards compatible with v7
* in the future. Unfortunately, there is no 'Features' field to
* indicate that Thumb-2 is supported.
*/
if (end > cpuArch && archNumber >= 7) {
g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_ARMv7;
}
free(cpuArch);
}
}
/* Extract the list of CPU features from 'Features' field */
{
char* cpuFeatures = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "Features");
if (cpuFeatures != NULL) {
D("found cpuFeatures = '%s'\n", cpuFeatures);
if (has_list_item(cpuFeatures, "vfpv3"))
g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
if (has_list_item(cpuFeatures, "neon"))
g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON;
free(cpuFeatures);
}
}
}
#endif /* __ARM_ARCH__ */
}
AndroidCpuFamily
android_getCpuFamily(void)
{
pthread_once(&g_once, android_cpuInit);
return g_cpuFamily;
}
uint64_t
android_getCpuFeatures(void)
{
pthread_once(&g_once, android_cpuInit);
return g_cpuFeatures;
}