source-engine/thirdparty/openssl/crypto/armcap.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <setjmp.h>
#include <signal.h>
#include <crypto.h>

#include "arm_arch.h"

unsigned int OPENSSL_armcap_P;

static sigset_t all_masked;

static sigjmp_buf ill_jmp;
static void ill_handler(int sig)
{
    siglongjmp(ill_jmp, sig);
}

/*
 * Following subroutines could have been inlined, but it's not all
 * ARM compilers support inline assembler...
 */
void _armv7_neon_probe(void);
unsigned int _armv7_tick(void);

unsigned int OPENSSL_rdtsc(void)
{
    if (OPENSSL_armcap_P & ARMV7_TICK)
        return _armv7_tick();
    else
        return 0;
}

#if defined(__GNUC__) && __GNUC__>=2
void OPENSSL_cpuid_setup(void) __attribute__ ((constructor));
#endif
void OPENSSL_cpuid_setup(void)
{
    char *e;
    struct sigaction ill_oact, ill_act;
    sigset_t oset;
    static int trigger = 0;

    if (trigger)
        return;
    trigger = 1;

    if ((e = getenv("OPENSSL_armcap"))) {
        OPENSSL_armcap_P = strtoul(e, NULL, 0);
        return;
    }

    sigfillset(&all_masked);
    sigdelset(&all_masked, SIGILL);
    sigdelset(&all_masked, SIGTRAP);
    sigdelset(&all_masked, SIGFPE);
    sigdelset(&all_masked, SIGBUS);
    sigdelset(&all_masked, SIGSEGV);

    OPENSSL_armcap_P = 0;

    memset(&ill_act, 0, sizeof(ill_act));
    ill_act.sa_handler = ill_handler;
    ill_act.sa_mask = all_masked;

    sigprocmask(SIG_SETMASK, &ill_act.sa_mask, &oset);
    sigaction(SIGILL, &ill_act, &ill_oact);

    if (sigsetjmp(ill_jmp, 1) == 0) {
        _armv7_neon_probe();
        OPENSSL_armcap_P |= ARMV7_NEON;
    }
    if (sigsetjmp(ill_jmp, 1) == 0) {
        _armv7_tick();
        OPENSSL_armcap_P |= ARMV7_TICK;
    }

    sigaction(SIGILL, &ill_oact, NULL);
    sigprocmask(SIG_SETMASK, &oset, NULL);
}