openssl/crypto/loongarchcap.c
Xi Ruoyao c612289b77 vpaes: LoongArch: Use getauxval(AT_HWCAP) for LSX detection
Running LSX instructions requires both the hardware support and the
kernel support.  The `cpucfg` instruction only tests the hardware
support, causing a SIGILL if the hardware supports LSX but the kernel
does not.

Use `getauxval(AT_HWCAP)` as the ["Software Development and Build
Convention for LoongArch Architectures"][1] manual suggests.

The LOONGARCH_HWCAP_LSX and LOONGARCH_HWCAP_LASX bits are copied from
the manual too.  In Glibc 2.38 they'll be provided by <sys/auxv.h> as
well, but they are unavailable in earlier Glibc versions so we cannot
rely on it.

The getauxval syscall and Glibc wrapper are available since day one
(Linux-5.19 and Glibc-2.36) for LoongArch.

Fixes #21508.

[1]:https://github.com/loongson/la-softdev-convention/blob/master/la-softdev-convention.adoc#kernel-constraints

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21509)
2023-07-28 12:39:41 +10:00

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C

/*
* Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <sys/auxv.h>
#include "loongarch_arch.h"
unsigned int OPENSSL_loongarch_hwcap_P = 0;
void OPENSSL_cpuid_setup(void)
{
OPENSSL_loongarch_hwcap_P = getauxval(AT_HWCAP);
}