386 lines
11 KiB
C
386 lines
11 KiB
C
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/*
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* Copyright (C) 2010 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/* ChangeLog for this library:
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*
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* NDK r5: Handle buggy kernels which report a CPU Architecture number of 7
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* for an ARMv6 CPU (see below).
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*
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* Handle kernels that only report 'neon', and not 'vfpv3'
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* (VFPv3 is mandated by the ARM architecture is Neon is implemented)
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*
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* Handle kernels that only report 'vfpv3d16', and not 'vfpv3'
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*
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* Fix x86 compilation. Report ANDROID_CPU_FAMILY_X86 in
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* android_getCpuFamily().
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*
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* NDK r4: Initial release
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*/
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#include <sys/system_properties.h>
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#ifdef __arm__
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#include <machine/cpu-features.h>
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#endif
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#include <pthread.h>
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#include "cpu-features.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <errno.h>
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static pthread_once_t g_once;
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static AndroidCpuFamily g_cpuFamily;
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static uint64_t g_cpuFeatures;
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static int g_cpuCount;
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static const int android_cpufeatures_debug = 0;
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#ifdef __arm__
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# define DEFAULT_CPU_FAMILY ANDROID_CPU_FAMILY_ARM
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#elif defined __i386__
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# define DEFAULT_CPU_FAMILY ANDROID_CPU_FAMILY_X86
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#else
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# define DEFAULT_CPU_FAMILY ANDROID_CPU_FAMILY_UNKNOWN
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#endif
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#define D(...) \
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do { \
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if (android_cpufeatures_debug) { \
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printf(__VA_ARGS__); fflush(stdout); \
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} \
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} while (0)
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/* Read the content of /proc/cpuinfo into a user-provided buffer.
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* Return the length of the data, or -1 on error. Does *not*
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* zero-terminate the content. Will not read more
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* than 'buffsize' bytes.
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*/
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static int
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read_file(const char* pathname, char* buffer, size_t buffsize)
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{
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int fd, len;
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fd = open(pathname, O_RDONLY);
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if (fd < 0)
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return -1;
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do {
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len = read(fd, buffer, buffsize);
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} while (len < 0 && errno == EINTR);
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close(fd);
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return len;
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}
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/* Extract the content of a the first occurence of a given field in
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* the content of /proc/cpuinfo and return it as a heap-allocated
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* string that must be freed by the caller.
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*
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* Return NULL if not found
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*/
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static char*
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extract_cpuinfo_field(char* buffer, int buflen, const char* field)
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{
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int fieldlen = strlen(field);
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char* bufend = buffer + buflen;
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char* result = NULL;
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int len, ignore;
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const char *p, *q;
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/* Look for first field occurence, and ensures it starts the line.
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*/
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p = buffer;
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bufend = buffer + buflen;
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for (;;) {
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p = memmem(p, bufend-p, field, fieldlen);
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if (p == NULL)
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goto EXIT;
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if (p == buffer || p[-1] == '\n')
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break;
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p += fieldlen;
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}
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/* Skip to the first column followed by a space */
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p += fieldlen;
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p = memchr(p, ':', bufend-p);
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if (p == NULL || p[1] != ' ')
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goto EXIT;
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/* Find the end of the line */
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p += 2;
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q = memchr(p, '\n', bufend-p);
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if (q == NULL)
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q = bufend;
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/* Copy the line into a heap-allocated buffer */
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len = q-p;
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result = malloc(len+1);
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if (result == NULL)
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goto EXIT;
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memcpy(result, p, len);
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result[len] = '\0';
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EXIT:
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return result;
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}
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/* Count the number of occurences of a given field prefix in /proc/cpuinfo.
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*/
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static int
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count_cpuinfo_field(char* buffer, int buflen, const char* field)
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{
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int fieldlen = strlen(field);
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const char* p = buffer;
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const char* bufend = buffer + buflen;
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const char* q;
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int count = 0;
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for (;;) {
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const char* q;
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p = memmem(p, bufend-p, field, fieldlen);
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if (p == NULL)
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break;
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/* Ensure that the field is at the start of a line */
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if (p > buffer && p[-1] != '\n') {
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p += fieldlen;
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continue;
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}
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/* skip any whitespace */
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q = p + fieldlen;
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while (q < bufend && (*q == ' ' || *q == '\t'))
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q++;
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/* we must have a colon now */
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if (q < bufend && *q == ':') {
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count += 1;
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q ++;
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}
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p = q;
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}
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return count;
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}
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/* Like strlen(), but for constant string literals */
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#define STRLEN_CONST(x) ((sizeof(x)-1)
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/* Checks that a space-separated list of items contains one given 'item'.
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* Returns 1 if found, 0 otherwise.
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*/
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static int
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has_list_item(const char* list, const char* item)
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{
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const char* p = list;
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int itemlen = strlen(item);
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if (list == NULL)
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return 0;
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while (*p) {
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const char* q;
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/* skip spaces */
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while (*p == ' ' || *p == '\t')
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p++;
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/* find end of current list item */
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q = p;
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while (*q && *q != ' ' && *q != '\t')
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q++;
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if (itemlen == q-p && !memcmp(p, item, itemlen))
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return 1;
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/* skip to next item */
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p = q;
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}
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return 0;
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}
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static void
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android_cpuInit(void)
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{
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char cpuinfo[4096];
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int cpuinfo_len;
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g_cpuFamily = DEFAULT_CPU_FAMILY;
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g_cpuFeatures = 0;
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g_cpuCount = 1;
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cpuinfo_len = read_file("/proc/cpuinfo", cpuinfo, sizeof cpuinfo);
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D("cpuinfo_len is (%d):\n%.*s\n", cpuinfo_len,
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cpuinfo_len >= 0 ? cpuinfo_len : 0, cpuinfo);
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if (cpuinfo_len < 0) /* should not happen */ {
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return;
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}
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/* Count the CPU cores, the value may be 0 for single-core CPUs */
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g_cpuCount = count_cpuinfo_field(cpuinfo, cpuinfo_len, "processor");
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if (g_cpuCount == 0) {
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g_cpuCount = count_cpuinfo_field(cpuinfo, cpuinfo_len, "Processor");
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if (g_cpuCount == 0) {
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g_cpuCount = 1;
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}
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}
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D("found cpuCount = %d\n", g_cpuCount);
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#ifdef __ARM_ARCH__
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{
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char* features = NULL;
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char* architecture = NULL;
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/* Extract architecture from the "CPU Architecture" field.
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* The list is well-known, unlike the the output of
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* the 'Processor' field which can vary greatly.
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*
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* See the definition of the 'proc_arch' array in
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* $KERNEL/arch/arm/kernel/setup.c and the 'c_show' function in
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* same file.
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*/
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char* cpuArch = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "CPU architecture");
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if (cpuArch != NULL) {
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char* end;
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long archNumber;
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int hasARMv7 = 0;
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D("found cpuArch = '%s'\n", cpuArch);
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/* read the initial decimal number, ignore the rest */
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archNumber = strtol(cpuArch, &end, 10);
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/* Here we assume that ARMv8 will be upwards compatible with v7
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* in the future. Unfortunately, there is no 'Features' field to
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* indicate that Thumb-2 is supported.
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*/
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if (end > cpuArch && archNumber >= 7) {
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hasARMv7 = 1;
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}
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/* Unfortunately, it seems that certain ARMv6-based CPUs
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* report an incorrect architecture number of 7!
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*
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* See http://code.google.com/p/android/issues/detail?id=10812
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*
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* We try to correct this by looking at the 'elf_format'
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* field reported by the 'Processor' field, which is of the
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* form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
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* an ARMv6-one.
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*/
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if (hasARMv7) {
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char* cpuProc = extract_cpuinfo_field(cpuinfo, cpuinfo_len,
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"Processor");
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if (cpuProc != NULL) {
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D("found cpuProc = '%s'\n", cpuProc);
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if (has_list_item(cpuProc, "(v6l)")) {
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D("CPU processor and architecture mismatch!!\n");
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hasARMv7 = 0;
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}
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free(cpuProc);
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}
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}
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if (hasARMv7) {
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g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_ARMv7;
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}
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/* The LDREX / STREX instructions are available from ARMv6 */
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if (archNumber >= 6) {
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g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_LDREX_STREX;
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}
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free(cpuArch);
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}
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/* Extract the list of CPU features from 'Features' field */
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char* cpuFeatures = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "Features");
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if (cpuFeatures != NULL) {
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D("found cpuFeatures = '%s'\n", cpuFeatures);
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if (has_list_item(cpuFeatures, "vfpv3"))
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g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
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else if (has_list_item(cpuFeatures, "vfpv3d16"))
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g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
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if (has_list_item(cpuFeatures, "neon")) {
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/* Note: Certain kernels only report neon but not vfpv3
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* in their features list. However, ARM mandates
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* that if Neon is implemented, so must be VFPv3
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* so always set the flag.
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*/
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g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON |
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ANDROID_CPU_ARM_FEATURE_VFPv3;
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}
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free(cpuFeatures);
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}
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}
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#endif /* __ARM_ARCH__ */
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#ifdef __i386__
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g_cpuFamily = ANDROID_CPU_FAMILY_X86;
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#endif
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}
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AndroidCpuFamily
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android_getCpuFamily(void)
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{
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pthread_once(&g_once, android_cpuInit);
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return g_cpuFamily;
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}
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uint64_t
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android_getCpuFeatures(void)
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{
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pthread_once(&g_once, android_cpuInit);
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return g_cpuFeatures;
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}
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int
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android_getCpuCount(void)
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{
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pthread_once(&g_once, android_cpuInit);
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return g_cpuCount;
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}
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