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);
void _armv8_aes_probe(void);
void _armv8_sha1_probe(void);
void _armv8_sha256_probe(void);
void _armv8_pmull_probe(void);
unsigned long _armv7_tick(void);

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

/*
 * Use a weak reference to getauxval() so we can use it if it is available but
 * don't break the build if it is not.
 */
#if defined(__GNUC__) && __GNUC__>=2
void OPENSSL_cpuid_setup(void) __attribute__((constructor));
extern unsigned long getauxval(unsigned long type) __attribute__((weak));
#else
static unsigned long (*getauxval)(unsigned long) = NULL;
#endif

/*
 * ARM puts the the feature bits for Crypto Extensions in AT_HWCAP2, whereas
 * AArch64 used AT_HWCAP.
 */
#if defined(__arm__) || defined (__arm)
# define HWCAP			16	/* AT_HWCAP */
# define HWCAP_NEON		(1 << 12)

# define HWCAP_CE		26	/* AT_HWCAP2 */
# define HWCAP_CE_AES		(1 << 0)
# define HWCAP_CE_PMULL		(1 << 1)
# define HWCAP_CE_SHA1		(1 << 2)
# define HWCAP_CE_SHA256	(1 << 3)
#elif defined(__aarch64__)
# define HWCAP			16	/* AT_HWCAP */
# define HWCAP_NEON		(1 << 1)

# define HWCAP_CE		HWCAP
# define HWCAP_CE_AES		(1 << 3)
# define HWCAP_CE_PMULL		(1 << 4)
# define HWCAP_CE_SHA1		(1 << 5)
# define HWCAP_CE_SHA256	(1 << 6)
#endif

#ifdef ANDROID
// Works around a bug where Android versions up to and including L don't
// properly restore the signal mask when asked.
#define sigsetjmp(env,savesigs) \
	(sigprocmask(SIG_SETMASK,&ill_act.sa_mask,NULL), \
	 sigsetjmp(env,savesigs))
#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=(unsigned int)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 (getauxval != NULL)
		{
		if (getauxval(HWCAP) & HWCAP_NEON)
			{
			unsigned long hwcap = getauxval(HWCAP_CE);

			OPENSSL_armcap_P |= ARMV7_NEON;

			if (hwcap & HWCAP_CE_AES)
				OPENSSL_armcap_P |= ARMV8_AES;

			if (hwcap & HWCAP_CE_PMULL)
				OPENSSL_armcap_P |= ARMV8_PMULL;

			if (hwcap & HWCAP_CE_SHA1)
				OPENSSL_armcap_P |= ARMV8_SHA1;

			if (hwcap & HWCAP_CE_SHA256)
				OPENSSL_armcap_P |= ARMV8_SHA256;
			}
		}
	else if (sigsetjmp(ill_jmp,1) == 0)
		{
		_armv7_neon_probe();
		OPENSSL_armcap_P |= ARMV7_NEON;
		if (sigsetjmp(ill_jmp,1) == 0)
			{
			_armv8_pmull_probe();
			OPENSSL_armcap_P |= ARMV8_PMULL|ARMV8_AES;
			}
		else if (sigsetjmp(ill_jmp,1) == 0)
			{
			_armv8_aes_probe();
			OPENSSL_armcap_P |= ARMV8_AES;
			}
		if (sigsetjmp(ill_jmp,1) == 0)
			{
			_armv8_sha1_probe();
			OPENSSL_armcap_P |= ARMV8_SHA1;
			}
		if (sigsetjmp(ill_jmp,1) == 0)
			{
			_armv8_sha256_probe();
			OPENSSL_armcap_P |= ARMV8_SHA256;
			}
		}
	if (sigsetjmp(ill_jmp,1) == 0)
		{
		_armv7_tick();
		OPENSSL_armcap_P |= ARMV7_TICK;
		}

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