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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include <aws/common/cpuid.h>
#include <stdlib.h>
#if defined(__linux__) || defined(__FreeBSD__)
# include <sys/auxv.h>
static unsigned long s_hwcap[2];
static bool s_hwcap_cached;
struct cap_bits {
unsigned long cap;
unsigned long bit;
};
# if (defined(__aarch64__))
struct cap_bits s_check_cap[AWS_CPU_FEATURE_COUNT] = {
[AWS_CPU_FEATURE_ARM_CRC] = {0, 1 << 7 /* HWCAP_CRC */},
};
# else
struct cap_bits s_check_cap[AWS_CPU_FEATURE_COUNT] = {
[AWS_CPU_FEATURE_ARM_CRC] = {1, 1 << 4 /* HWCAP_CRC */},
};
# endif
# if (defined(__linux__))
static void s_cache_hwcap(void) {
s_hwcap[0] = getauxval(AT_HWCAP);
s_hwcap[1] = getauxval(AT_HWCAP2);
s_hwcap_cached = true;
}
# elif (defined(__FreeBSD__))
static void s_cache_hwcap(void) {
int ret;
ret = elf_aux_info(AT_HWCAP, &s_hwcap[0], sizeof(unsigned long));
if (ret)
s_hwcap[0] = 0;
ret = elf_aux_info(AT_HWCAP2, &s_hwcap[1], sizeof(unsigned long));
if (ret)
s_hwcap[1] = 0;
s_hwcap_cached = true;
}
# else
# error "Unknown method"
# endif
bool aws_cpu_has_feature(enum aws_cpu_feature_name feature_name) {
if (!s_hwcap_cached)
s_cache_hwcap();
switch (feature_name) {
case AWS_CPU_FEATURE_ARM_CRC:
return s_hwcap[s_check_cap[feature_name].cap] & s_check_cap[feature_name].bit;
default:
return false;
}
}
#else /* defined(__linux__) || defined(__FreeBSD__) */
bool aws_cpu_has_feature(enum aws_cpu_feature_name feature_name) {
return false;
}
#endif /* defined(__linux__) || defined(__FreeBSD__) */
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