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hwf-arm.c
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/* hwf-arm.c - Detect hardware features - ARM part
* Copyright (C) 2013 Jussi Kivilinna <jussi.kivilinna@iki.fi>
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include "g10lib.h"
#include "hwf-common.h"
#if !defined (__arm__)
# error Module build for wrong CPU.
#endif
#undef HAS_SYS_AT_HWCAP
#undef HAS_PROC_CPUINFO
#ifdef __linux__
#define HAS_SYS_AT_HWCAP 1
#define AT_HWCAP 16
#define HWCAP_NEON 4096
static int
get_hwcap(unsigned int *hwcap)
{
struct { unsigned int a_type; unsigned int a_val; } auxv;
FILE *f;
int err = -1;
static int hwcap_initialized = 0;
static unsigned int stored_hwcap;
if (hwcap_initialized)
{
*hwcap = stored_hwcap;
return 0;
}
f = fopen("/proc/self/auxv", "r");
if (!f)
{
*hwcap = stored_hwcap;
return -1;
}
while (fread(&auxv, sizeof(auxv), 1, f) > 0)
{
if (auxv.a_type != AT_HWCAP)
continue;
stored_hwcap = auxv.a_val;
hwcap_initialized = 1;
err = 0;
break;
}
fclose(f);
*hwcap = stored_hwcap;
return err;
}
static unsigned int
detect_arm_at_hwcap(void)
{
unsigned int hwcap;
unsigned int features = 0;
if (get_hwcap(&hwcap) < 0)
return features;
#ifdef ENABLE_NEON_SUPPORT
if (hwcap & HWCAP_NEON)
features |= HWF_ARM_NEON;
#endif
return features;
}
#define HAS_PROC_CPUINFO 1
static unsigned int
detect_arm_proc_cpuinfo(unsigned int *broken_hwfs)
{
char buf[1024]; /* large enough */
char *str_features, *str_neon;
int cpu_implementer, cpu_arch, cpu_variant, cpu_part, cpu_revision;
FILE *f;
int readlen, i;
static int cpuinfo_initialized = 0;
static unsigned int stored_cpuinfo_features;
static unsigned int stored_broken_hwfs;
struct {
const char *name;
int *value;
} cpu_entries[5] = {
{ "CPU implementer", &cpu_implementer },
{ "CPU architecture", &cpu_arch },
{ "CPU variant", &cpu_variant },
{ "CPU part", &cpu_part },
{ "CPU revision", &cpu_revision },
};
if (cpuinfo_initialized)
{
*broken_hwfs |= stored_broken_hwfs;
return stored_cpuinfo_features;
}
f = fopen("/proc/cpuinfo", "r");
if (!f)
return 0;
memset (buf, 0, sizeof(buf));
readlen = fread (buf, 1, sizeof(buf), f);
fclose (f);
if (readlen <= 0 || readlen > sizeof(buf))
return 0;
buf[sizeof(buf) - 1] = '\0';
cpuinfo_initialized = 1;
stored_cpuinfo_features = 0;
stored_broken_hwfs = 0;
/* Find features line. */
str_features = strstr(buf, "Features");
if (!str_features)
return stored_cpuinfo_features;
/* Find CPU version information. */
for (i = 0; i < DIM(cpu_entries); i++)
{
char *str;
*cpu_entries[i].value = -1;
str = strstr(buf, cpu_entries[i].name);
if (!str)
continue;
str = strstr(str, ": ");
if (!str)
continue;
str += 2;
*cpu_entries[i].value = strtoul(str, NULL, 0);
}
/* Lines to strings. */
for (i = 0; i < sizeof(buf); i++)
if (buf[i] == '\n')
buf[i] = '\0';
/* Check for NEON. */
str_neon = strstr(str_features, " neon");
if (str_neon && (str_neon[5] == ' ' || str_neon[5] == '\0'))
stored_cpuinfo_features |= HWF_ARM_NEON;
/* Check for CPUs with broken NEON implementation. See
* https://code.google.com/p/chromium/issues/detail?id=341598
*/
if (cpu_implementer == 0x51
&& cpu_arch == 7
&& cpu_variant == 1
&& cpu_part == 0x4d
&& cpu_revision == 0)
{
stored_broken_hwfs = HWF_ARM_NEON;
}
*broken_hwfs |= stored_broken_hwfs;
return stored_cpuinfo_features;
}
#endif /* __linux__ */
unsigned int
_gcry_hwf_detect_arm (void)
{
unsigned int ret = 0;
unsigned int broken_hwfs = 0;
#if defined (HAS_SYS_AT_HWCAP)
ret |= detect_arm_at_hwcap ();
#endif
#if defined (HAS_PROC_CPUINFO)
ret |= detect_arm_proc_cpuinfo (&broken_hwfs);
#endif
#if defined(__ARM_NEON__) && defined(ENABLE_NEON_SUPPORT)
ret |= HWF_ARM_NEON;
#endif
ret &= ~broken_hwfs;
return ret;
}

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Expires
Thu, Jul 17, 12:46 AM (1 d, 12 m)
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