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- /* Copyright (c) 2016, Google Inc.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
- * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
- * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
- * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
-
- #include <openssl/cpu.h>
-
- #if defined(OPENSSL_ARM) && !defined(OPENSSL_STATIC_ARMCAP)
-
- #include <errno.h>
- #include <fcntl.h>
- #include <string.h>
- #include <sys/types.h>
- #include <unistd.h>
-
- #include <openssl/arm_arch.h>
- #include <openssl/buf.h>
- #include <openssl/mem.h>
-
- #include "internal.h"
-
-
- #define AT_HWCAP 16
- #define AT_HWCAP2 26
-
- #define HWCAP_NEON (1 << 12)
-
- // See /usr/include/asm/hwcap.h on an ARM installation for the source of
- // these values.
- #define HWCAP2_AES (1 << 0)
- #define HWCAP2_PMULL (1 << 1)
- #define HWCAP2_SHA1 (1 << 2)
- #define HWCAP2_SHA2 (1 << 3)
-
- // |getauxval| is not available on Android until API level 20. Link it as a weak
- // symbol and use other methods as fallback.
- unsigned long getauxval(unsigned long type) __attribute__((weak));
-
- static int open_eintr(const char *path, int flags) {
- int ret;
- do {
- ret = open(path, flags);
- } while (ret < 0 && errno == EINTR);
- return ret;
- }
-
- static ssize_t read_eintr(int fd, void *out, size_t len) {
- ssize_t ret;
- do {
- ret = read(fd, out, len);
- } while (ret < 0 && errno == EINTR);
- return ret;
- }
-
- // read_full reads exactly |len| bytes from |fd| to |out|. On error or end of
- // file, it returns zero.
- static int read_full(int fd, void *out, size_t len) {
- char *outp = out;
- while (len > 0) {
- ssize_t ret = read_eintr(fd, outp, len);
- if (ret <= 0) {
- return 0;
- }
- outp += ret;
- len -= ret;
- }
- return 1;
- }
-
- // read_file opens |path| and reads until end-of-file. On success, it returns
- // one and sets |*out_ptr| and |*out_len| to a newly-allocated buffer with the
- // contents. Otherwise, it returns zero.
- static int read_file(char **out_ptr, size_t *out_len, const char *path) {
- int fd = open_eintr(path, O_RDONLY);
- if (fd < 0) {
- return 0;
- }
-
- static const size_t kReadSize = 1024;
- int ret = 0;
- size_t cap = kReadSize, len = 0;
- char *buf = OPENSSL_malloc(cap);
- if (buf == NULL) {
- goto err;
- }
-
- for (;;) {
- if (cap - len < kReadSize) {
- size_t new_cap = cap * 2;
- if (new_cap < cap) {
- goto err;
- }
- char *new_buf = OPENSSL_realloc(buf, new_cap);
- if (new_buf == NULL) {
- goto err;
- }
- buf = new_buf;
- cap = new_cap;
- }
-
- ssize_t bytes_read = read_eintr(fd, buf + len, kReadSize);
- if (bytes_read < 0) {
- goto err;
- }
- if (bytes_read == 0) {
- break;
- }
- len += bytes_read;
- }
-
- *out_ptr = buf;
- *out_len = len;
- ret = 1;
- buf = NULL;
-
- err:
- OPENSSL_free(buf);
- close(fd);
- return ret;
- }
-
- // getauxval_proc behaves like |getauxval| but reads from /proc/self/auxv.
- static unsigned long getauxval_proc(unsigned long type) {
- int fd = open_eintr("/proc/self/auxv", O_RDONLY);
- if (fd < 0) {
- return 0;
- }
-
- struct {
- unsigned long tag;
- unsigned long value;
- } entry;
-
- for (;;) {
- if (!read_full(fd, &entry, sizeof(entry)) ||
- (entry.tag == 0 && entry.value == 0)) {
- break;
- }
- if (entry.tag == type) {
- close(fd);
- return entry.value;
- }
- }
- close(fd);
- return 0;
- }
-
- typedef struct {
- const char *data;
- size_t len;
- } STRING_PIECE;
-
- static int STRING_PIECE_equals(const STRING_PIECE *a, const char *b) {
- size_t b_len = strlen(b);
- return a->len == b_len && OPENSSL_memcmp(a->data, b, b_len) == 0;
- }
-
- // STRING_PIECE_split finds the first occurence of |sep| in |in| and, if found,
- // sets |*out_left| and |*out_right| to |in| split before and after it. It
- // returns one if |sep| was found and zero otherwise.
- static int STRING_PIECE_split(STRING_PIECE *out_left, STRING_PIECE *out_right,
- const STRING_PIECE *in, char sep) {
- const char *p = OPENSSL_memchr(in->data, sep, in->len);
- if (p == NULL) {
- return 0;
- }
- // |out_left| or |out_right| may alias |in|, so make a copy.
- STRING_PIECE in_copy = *in;
- out_left->data = in_copy.data;
- out_left->len = p - in_copy.data;
- out_right->data = in_copy.data + out_left->len + 1;
- out_right->len = in_copy.len - out_left->len - 1;
- return 1;
- }
-
- // STRING_PIECE_trim removes leading and trailing whitespace from |s|.
- static void STRING_PIECE_trim(STRING_PIECE *s) {
- while (s->len != 0 && (s->data[0] == ' ' || s->data[0] == '\t')) {
- s->data++;
- s->len--;
- }
- while (s->len != 0 &&
- (s->data[s->len - 1] == ' ' || s->data[s->len - 1] == '\t')) {
- s->len--;
- }
- }
-
- // extract_cpuinfo_field extracts a /proc/cpuinfo field named |field| from
- // |in|. If found, it sets |*out| to the value and returns one. Otherwise, it
- // returns zero.
- static int extract_cpuinfo_field(STRING_PIECE *out, const STRING_PIECE *in,
- const char *field) {
- // Process |in| one line at a time.
- STRING_PIECE remaining = *in, line;
- while (STRING_PIECE_split(&line, &remaining, &remaining, '\n')) {
- STRING_PIECE key, value;
- if (!STRING_PIECE_split(&key, &value, &line, ':')) {
- continue;
- }
- STRING_PIECE_trim(&key);
- if (STRING_PIECE_equals(&key, field)) {
- STRING_PIECE_trim(&value);
- *out = value;
- return 1;
- }
- }
-
- return 0;
- }
-
- static int cpuinfo_field_equals(const STRING_PIECE *cpuinfo, const char *field,
- const char *value) {
- STRING_PIECE extracted;
- return extract_cpuinfo_field(&extracted, cpuinfo, field) &&
- STRING_PIECE_equals(&extracted, value);
- }
-
- // has_list_item treats |list| as a space-separated list of items and returns
- // one if |item| is contained in |list| and zero otherwise.
- static int has_list_item(const STRING_PIECE *list, const char *item) {
- STRING_PIECE remaining = *list, feature;
- while (STRING_PIECE_split(&feature, &remaining, &remaining, ' ')) {
- if (STRING_PIECE_equals(&feature, item)) {
- return 1;
- }
- }
- return 0;
- }
-
- static unsigned long get_hwcap_cpuinfo(const STRING_PIECE *cpuinfo) {
- if (cpuinfo_field_equals(cpuinfo, "CPU architecture", "8")) {
- // This is a 32-bit ARM binary running on a 64-bit kernel. NEON is always
- // available on ARMv8. Linux omits required features, so reading the
- // "Features" line does not work. (For simplicity, use strict equality. We
- // assume everything running on future ARM architectures will have a
- // working |getauxval|.)
- return HWCAP_NEON;
- }
-
- STRING_PIECE features;
- if (extract_cpuinfo_field(&features, cpuinfo, "Features") &&
- has_list_item(&features, "neon")) {
- return HWCAP_NEON;
- }
- return 0;
- }
-
- static unsigned long get_hwcap2_cpuinfo(const STRING_PIECE *cpuinfo) {
- STRING_PIECE features;
- if (!extract_cpuinfo_field(&features, cpuinfo, "Features")) {
- return 0;
- }
-
- unsigned long ret = 0;
- if (has_list_item(&features, "aes")) {
- ret |= HWCAP2_AES;
- }
- if (has_list_item(&features, "pmull")) {
- ret |= HWCAP2_PMULL;
- }
- if (has_list_item(&features, "sha1")) {
- ret |= HWCAP2_SHA1;
- }
- if (has_list_item(&features, "sha2")) {
- ret |= HWCAP2_SHA2;
- }
- return ret;
- }
-
- // has_broken_neon returns one if |in| matches a CPU known to have a broken
- // NEON unit. See https://crbug.com/341598.
- static int has_broken_neon(const STRING_PIECE *cpuinfo) {
- return cpuinfo_field_equals(cpuinfo, "CPU implementer", "0x51") &&
- cpuinfo_field_equals(cpuinfo, "CPU architecture", "7") &&
- cpuinfo_field_equals(cpuinfo, "CPU variant", "0x1") &&
- cpuinfo_field_equals(cpuinfo, "CPU part", "0x04d") &&
- cpuinfo_field_equals(cpuinfo, "CPU revision", "0");
- }
-
- extern uint32_t OPENSSL_armcap_P;
-
- static int g_has_broken_neon, g_needs_hwcap2_workaround;
-
- void OPENSSL_cpuid_setup(void) {
- char *cpuinfo_data;
- size_t cpuinfo_len;
- if (!read_file(&cpuinfo_data, &cpuinfo_len, "/proc/cpuinfo")) {
- return;
- }
- STRING_PIECE cpuinfo;
- cpuinfo.data = cpuinfo_data;
- cpuinfo.len = cpuinfo_len;
-
- // |getauxval| is not available on Android until API level 20. If it is
- // unavailable, read from /proc/self/auxv as a fallback. This is unreadable
- // on some versions of Android, so further fall back to /proc/cpuinfo.
- //
- // See
- // https://android.googlesource.com/platform/ndk/+/882ac8f3392858991a0e1af33b4b7387ec856bd2
- // and b/13679666 (Google-internal) for details.
- unsigned long hwcap = 0;
- if (getauxval != NULL) {
- hwcap = getauxval(AT_HWCAP);
- }
- if (hwcap == 0) {
- hwcap = getauxval_proc(AT_HWCAP);
- }
- if (hwcap == 0) {
- hwcap = get_hwcap_cpuinfo(&cpuinfo);
- }
-
- // Clear NEON support if known broken.
- g_has_broken_neon = has_broken_neon(&cpuinfo);
- if (g_has_broken_neon) {
- hwcap &= ~HWCAP_NEON;
- }
-
- // Matching OpenSSL, only report other features if NEON is present.
- if (hwcap & HWCAP_NEON) {
- OPENSSL_armcap_P |= ARMV7_NEON;
-
- // Some ARMv8 Android devices don't expose AT_HWCAP2. Fall back to
- // /proc/cpuinfo. See https://crbug.com/596156.
- unsigned long hwcap2 = 0;
- if (getauxval != NULL) {
- hwcap2 = getauxval(AT_HWCAP2);
- }
- if (hwcap2 == 0) {
- hwcap2 = get_hwcap2_cpuinfo(&cpuinfo);
- g_needs_hwcap2_workaround = hwcap2 != 0;
- }
-
- if (hwcap2 & HWCAP2_AES) {
- OPENSSL_armcap_P |= ARMV8_AES;
- }
- if (hwcap2 & HWCAP2_PMULL) {
- OPENSSL_armcap_P |= ARMV8_PMULL;
- }
- if (hwcap2 & HWCAP2_SHA1) {
- OPENSSL_armcap_P |= ARMV8_SHA1;
- }
- if (hwcap2 & HWCAP2_SHA2) {
- OPENSSL_armcap_P |= ARMV8_SHA256;
- }
- }
-
- OPENSSL_free(cpuinfo_data);
- }
-
- int CRYPTO_has_broken_NEON(void) { return g_has_broken_neon; }
-
- int CRYPTO_needs_hwcap2_workaround(void) { return g_needs_hwcap2_workaround; }
-
- #endif // OPENSSL_ARM && !OPENSSL_STATIC_ARMCAP
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