hwf-arm.c
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	/* hwf-arm.c - Detect hardware features - ARM part
	* Copyright (C) 2013,2019,2022 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 <errno.h>
	#if defined(HAVE_SYS_AUXV_H) && (defined(HAVE_GETAUXVAL) \|\| \
	defined(HAVE_ELF_AUX_INFO))
	#include <sys/auxv.h>
	#endif
	#if defined(__APPLE__) && defined(HAVE_SYS_SYSCTL_H) && \
	defined(HAVE_SYSCTLBYNAME)
	#include <sys/sysctl.h>
	#endif

	#include "g10lib.h"
	#include "hwf-common.h"

	#if !defined (__arm__) && !defined (__aarch64__)
	# error Module build for wrong CPU.
	#endif


	#if defined(HAVE_SYS_AUXV_H) && defined(HAVE_ELF_AUX_INFO) && \
	!defined(HAVE_GETAUXVAL) && defined(AT_HWCAP)
	#define HAVE_GETAUXVAL
	static unsigned long getauxval(unsigned long type)
	{
	unsigned long auxval = 0;
	int err;

	/* FreeBSD provides 'elf_aux_info' function that does the same as
	* 'getauxval' on Linux. */

	err = elf_aux_info (type, &auxval, sizeof(auxval));
	if (err)
	{
	errno = err;
	auxval = 0;
	}

	return auxval;
	}
	#endif


	#undef HAS_SYS_AT_HWCAP
	#if defined(__linux__) \|\| \
	(defined(HAVE_SYS_AUXV_H) && defined(HAVE_GETAUXVAL))
	#define HAS_SYS_AT_HWCAP 1

	struct feature_map_s {
	unsigned int hwcap_flag;
	unsigned int hwcap2_flag;
	const char *feature_match;
	unsigned int hwf_flag;
	};

	#ifdef __arm__

	/* Note: These macros have same values on Linux and FreeBSD. */
	#ifndef AT_HWCAP
	# define AT_HWCAP 16
	#endif
	#ifndef AT_HWCAP2
	# define AT_HWCAP2 26
	#endif

	#ifndef HWCAP_NEON
	# define HWCAP_NEON 4096
	#endif

	#ifndef HWCAP2_AES
	# define HWCAP2_AES 1
	#endif
	#ifndef HWCAP2_PMULL
	# define HWCAP2_PMULL 2
	#endif
	#ifndef HWCAP2_SHA1
	# define HWCAP2_SHA1 4
	#endif
	#ifndef HWCAP2_SHA2
	# define HWCAP2_SHA2 8
	#endif

	static const struct feature_map_s arm_features[] =
	{
	#ifdef ENABLE_NEON_SUPPORT
	{ HWCAP_NEON, 0, " neon", HWF_ARM_NEON },
	#endif
	#ifdef ENABLE_ARM_CRYPTO_SUPPORT
	{ 0, HWCAP2_AES, " aes", HWF_ARM_AES },
	{ 0, HWCAP2_SHA1," sha1", HWF_ARM_SHA1 },
	{ 0, HWCAP2_SHA2, " sha2", HWF_ARM_SHA2 },
	{ 0, HWCAP2_PMULL, " pmull", HWF_ARM_PMULL },
	#endif
	};

	#elif defined(__aarch64__)

	/* Note: These macros have same values on Linux and FreeBSD. */
	#ifndef AT_HWCAP
	# define AT_HWCAP 16
	#endif
	#ifndef AT_HWCAP2
	# define AT_HWCAP2 -1
	#endif

	#ifndef HWCAP_ASIMD
	# define HWCAP_ASIMD 2
	#endif
	#ifndef HWCAP_AES
	# define HWCAP_AES 8
	#endif
	#ifndef HWCAP_PMULL
	# define HWCAP_PMULL 16
	#endif
	#ifndef HWCAP_SHA1
	# define HWCAP_SHA1 32
	#endif
	#ifndef HWCAP_SHA2
	# define HWCAP_SHA2 64
	#endif
	#ifndef HWCAP_SHA3
	# define HWCAP_SHA3 (1 << 17)
	#endif
	#ifndef HWCAP_SM3
	# define HWCAP_SM3 (1 << 18)
	#endif
	#ifndef HWCAP_SM4
	# define HWCAP_SM4 (1 << 19)
	#endif
	#ifndef HWCAP_SHA512
	# define HWCAP_SHA512 (1 << 21)
	#endif
	#ifndef HWCAP_SVE
	# define HWCAP_SVE (1 << 22)
	#endif

	#ifndef HWCAP2_SVE2
	# define HWCAP2_SVE2 (1 << 1)
	#endif
	#ifndef HWCAP2_SVEAES
	# define HWCAP2_SVEAES (1 << 2)
	#endif
	#ifndef HWCAP2_SVEPMULL
	# define HWCAP2_SVEPMULL (1 << 3)
	#endif
	#ifndef HWCAP2_SVESHA3
	# define HWCAP2_SVESHA3 (1 << 5)
	#endif
	#ifndef HWCAP2_SVESM4
	# define HWCAP2_SVESM4 (1 << 6)
	#endif

	static const struct feature_map_s arm_features[] =
	{
	#ifdef ENABLE_NEON_SUPPORT
	{ HWCAP_ASIMD, 0, " asimd", HWF_ARM_NEON },
	#endif
	#ifdef ENABLE_ARM_CRYPTO_SUPPORT
	{ HWCAP_AES, 0, " aes", HWF_ARM_AES },
	{ HWCAP_SHA1, 0, " sha1", HWF_ARM_SHA1 },
	{ HWCAP_SHA2, 0, " sha2", HWF_ARM_SHA2 },
	{ HWCAP_PMULL, 0, " pmull", HWF_ARM_PMULL },
	{ HWCAP_SHA3, 0, " sha3", HWF_ARM_SHA3 },
	{ HWCAP_SM3, 0, " sm3", HWF_ARM_SM3 },
	{ HWCAP_SM4, 0, " sm4", HWF_ARM_SM4 },
	{ HWCAP_SHA512, 0, " sha512", HWF_ARM_SHA512 },
	#endif
	#ifdef ENABLE_SVE_SUPPORT
	{ HWCAP_SVE, 0, " sve", HWF_ARM_SVE },
	{ 0, HWCAP2_SVE2, " sve2", HWF_ARM_SVE2 },
	{ 0, HWCAP2_SVEAES, " sveaes", HWF_ARM_SVEAES },
	{ 0, HWCAP2_SVEPMULL, " svepmull", HWF_ARM_SVEPMULL },
	{ 0, HWCAP2_SVESHA3, " svesha3", HWF_ARM_SVESHA3 },
	{ 0, HWCAP2_SVESM4, " svesm4", HWF_ARM_SVESM4 },
	#endif
	};

	#endif

	static int
	get_hwcap(unsigned int hwcap, unsigned int hwcap2)
	{
	struct { unsigned long a_type; unsigned long a_val; } auxv;
	FILE *f;
	int err = -1;
	static int hwcap_initialized = 0;
	static unsigned int stored_hwcap = 0;
	static unsigned int stored_hwcap2 = 0;

	if (hwcap_initialized)
	{
	*hwcap = stored_hwcap;
	*hwcap2 = stored_hwcap2;
	return 0;
	}

	#if defined(HAVE_SYS_AUXV_H) && defined(HAVE_GETAUXVAL)
	errno = 0;
	auxv.a_val = getauxval (AT_HWCAP);
	if (errno == 0)
	{
	stored_hwcap \|= auxv.a_val;
	hwcap_initialized = 1;
	}

	if (AT_HWCAP2 >= 0)
	{
	errno = 0;
	auxv.a_val = getauxval (AT_HWCAP2);
	if (errno == 0)
	{
	stored_hwcap2 \|= auxv.a_val;
	hwcap_initialized = 1;
	}
	}

	if (hwcap_initialized && (stored_hwcap \|\| stored_hwcap2))
	{
	*hwcap = stored_hwcap;
	*hwcap2 = stored_hwcap2;
	return 0;
	}
	#endif

	f = fopen("/proc/self/auxv", "r");
	if (!f)
	{
	*hwcap = stored_hwcap;
	*hwcap2 = stored_hwcap2;
	return -1;
	}

	while (fread(&auxv, sizeof(auxv), 1, f) > 0)
	{
	if (auxv.a_type == AT_HWCAP)
	{
	stored_hwcap \|= auxv.a_val;
	hwcap_initialized = 1;
	}

	if (auxv.a_type == AT_HWCAP2)
	{
	stored_hwcap2 \|= auxv.a_val;
	hwcap_initialized = 1;
	}
	}

	if (hwcap_initialized)
	err = 0;

	fclose(f);
	*hwcap = stored_hwcap;
	*hwcap2 = stored_hwcap2;
	return err;
	}

	static unsigned int
	detect_arm_at_hwcap(void)
	{
	unsigned int hwcap;
	unsigned int hwcap2;
	unsigned int features = 0;
	unsigned int i;

	if (get_hwcap(&hwcap, &hwcap2) < 0)
	return features;

	for (i = 0; i < DIM(arm_features); i++)
	{
	if (hwcap & arm_features[i].hwcap_flag)
	features \|= arm_features[i].hwf_flag;

	if (hwcap2 & arm_features[i].hwcap2_flag)
	features \|= arm_features[i].hwf_flag;
	}

	return features;
	}

	#endif

	#undef HAS_PROC_CPUINFO
	#ifdef __linux__
	#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_feat;
	int cpu_implementer, cpu_arch, cpu_variant, cpu_part, cpu_revision;
	FILE *f;
	int readlen, i;
	size_t mlen;
	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;
	if (strcmp(cpu_entries[i].name, "CPU architecture") == 0
	&& strcmp(str, "AArch64") == 0)
	*cpu_entries[i].value = 8;
	else
	*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 features. */
	for (i = 0; i < DIM(arm_features); i++)
	{
	str_feat = strstr(str_features, arm_features[i].feature_match);
	if (str_feat)
	{
	mlen = strlen(arm_features[i].feature_match);
	if (str_feat[mlen] == ' ' \|\| str_feat[mlen] == '\0')
	{
	stored_cpuinfo_features \|= arm_features[i].hwf_flag;
	}
	}
	}

	/* 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__ */


	#undef HAS_APPLE_SYSCTLBYNAME
	#if defined(__APPLE__) && defined(HAVE_SYS_SYSCTL_H) && \
	defined(HAVE_SYSCTLBYNAME)
	#define HAS_APPLE_SYSCTLBYNAME 1

	static unsigned int
	detect_arm_apple_sysctlbyname (void)
	{
	static const struct
	{
	const char *feat_name;
	unsigned int hwf_flag;
	} hw_optional_arm_features[] =
	{
	#ifdef ENABLE_NEON_SUPPORT
	{ "hw.optional.neon", HWF_ARM_NEON },
	{ "hw.optional.AdvSIMD", HWF_ARM_NEON },
	#endif
	#ifdef ENABLE_ARM_CRYPTO_SUPPORT
	{ "hw.optional.arm.FEAT_AES", HWF_ARM_AES },
	{ "hw.optional.arm.FEAT_SHA1", HWF_ARM_SHA1 },
	{ "hw.optional.arm.FEAT_SHA256", HWF_ARM_SHA2 },
	{ "hw.optional.arm.FEAT_PMULL", HWF_ARM_PMULL },
	{ "hw.optional.arm.FEAT_SHA3", HWF_ARM_SHA3 },
	{ "hw.optional.armv8_2_sha3", HWF_ARM_SHA3 },
	{ "hw.optional.arm.FEAT_SHA512", HWF_ARM_SHA512 },
	{ "hw.optional.armv8_2_sha512", HWF_ARM_SHA512 },
	#endif
	};
	unsigned int i;
	unsigned int hwf = 0;

	for (i = 0; i < DIM(hw_optional_arm_features); i++)
	{
	const char *name = hw_optional_arm_features[i].feat_name;
	int sysctl_value = 0;
	size_t value_size = sizeof(sysctl_value);

	if (sysctlbyname (name, &sysctl_value, &value_size, NULL, 0) != 0)
	continue;

	if (value_size != sizeof(sysctl_value))
	continue;

	if (sysctl_value == 1)
	{
	hwf \|= hw_optional_arm_features[i].hwf_flag;
	}
	}

	return hwf;
	}

	#endif /* __APPLE__ */


	static unsigned int
	detect_arm_hwf_by_toolchain (void)
	{
	unsigned int ret = 0;

	/* Detect CPU features required by toolchain.
	* This allows detection of ARMv8 crypto extension support,
	* for example, on macOS/aarch64.
	*/

	#if __GNUC__ >= 4

	#if defined(__ARM_NEON) && defined(ENABLE_NEON_SUPPORT)
	ret \|= HWF_ARM_NEON;

	#ifdef HAVE_GCC_INLINE_ASM_NEON
	/* Early test for NEON instruction to detect faulty toolchain
	* configuration. */
	asm volatile ("veor q15, q15, q15":::"q15");
	#endif

	#ifdef HAVE_GCC_INLINE_ASM_AARCH64_NEON
	/* Early test for NEON instruction to detect faulty toolchain
	* configuration. */
	asm volatile ("eor v31.16b, v31.16b, v31.16b":::"v31");
	#endif

	#endif /* __ARM_NEON */

	#if defined(__ARM_FEATURE_CRYPTO) && defined(ENABLE_ARM_CRYPTO_SUPPORT)
	/* ARMv8 crypto extensions include support for PMULL, AES, SHA1 and SHA2
	* instructions. */
	ret \|= HWF_ARM_PMULL;
	ret \|= HWF_ARM_AES;
	ret \|= HWF_ARM_SHA1;
	ret \|= HWF_ARM_SHA2;

	#ifdef HAVE_GCC_INLINE_ASM_AARCH32_CRYPTO
	/* Early test for CE instructions to detect faulty toolchain
	* configuration. */
	asm volatile ("vmull.p64 q0, d0, d0;\n\t"
	"aesimc.8 q7, q0;\n\t"
	"sha1su1.32 q0, q0;\n\t"
	"sha256su1.32 q0, q7, q15;\n\t"
	:::
	"q0", "q7", "q15");
	#endif

	#ifdef HAVE_GCC_INLINE_ASM_AARCH64_CRYPTO
	/* Early test for CE instructions to detect faulty toolchain
	* configuration. */
	asm volatile ("pmull2 v0.1q, v0.2d, v31.2d;\n\t"
	"aesimc v15.16b, v0.16b;\n\t"
	"sha1su1 v0.4s, v0.4s;\n\t"
	"sha256su1 v0.4s, v15.4s, v31.4s;\n\t"
	:::
	"v0", "v15", "v31");
	#endif
	#endif

	#endif

	return ret;
	}

	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 (HAS_APPLE_SYSCTLBYNAME)
	ret \|= detect_arm_apple_sysctlbyname ();
	#endif

	ret \|= detect_arm_hwf_by_toolchain ();

	ret &= ~broken_hwfs;

	return ret;
	}

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