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 #21509) (cherry picked from commit c612289)
openssl · Jul 28, 2023 · d64d53a · d64d53a
1 parent 4c1fc2c
commit d64d53a
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Showing 3 changed files with 7 additions and 13 deletions.
diff --git a/crypto/loongarch_arch.h b/crypto/loongarch_arch.h
@@ -9,9 +9,8 @@
 #ifndef OSSL_CRYPTO_LOONGARCH_ARCH_H
 # define OSSL_CRYPTO_LOONGARCH_ARCH_H
 
-extern unsigned int OPENSSL_loongarchcap_P;
-# define LOONGARCH_CFG2      0x02
-# define LOONGARCH_CFG2_LSX  (1<<6)
-# define LOONGARCH_CFG2_LASX (1<<7)
+extern unsigned int OPENSSL_loongarch_hwcap_P;
+# define LOONGARCH_HWCAP_LSX  (1 << 4)
+# define LOONGARCH_HWCAP_LASX (1 << 5)
 
 #endif
diff --git a/crypto/loongarchcap.c b/crypto/loongarchcap.c
@@ -6,17 +6,12 @@
  * 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_loongarchcap_P = 0;
+unsigned int OPENSSL_loongarch_hwcap_P = 0;
 
 void OPENSSL_cpuid_setup(void)
 {
-	unsigned int reg;
-	__asm__ volatile(
-	    "cpucfg %0, %1 \n\t"
-	    : "+&r"(reg)
-	    : "r"(LOONGARCH_CFG2)
-	);
-	OPENSSL_loongarchcap_P = reg;
+	OPENSSL_loongarch_hwcap_P = getauxval(AT_HWCAP);
 }
diff --git a/include/crypto/aes_platform.h b/include/crypto/aes_platform.h
@@ -165,7 +165,7 @@ void gcm_ghash_v8(u64 Xi[2],const u128 Htable[16],const u8 *inp, size_t len);
 # if defined(__loongarch__) || defined(__loongarch64)
 #  include "loongarch_arch.h"
 #  if defined(VPAES_ASM)
-#   define VPAES_CAPABLE  (OPENSSL_loongarchcap_P & LOONGARCH_CFG2_LSX)
+#   define VPAES_CAPABLE  (OPENSSL_loongarch_hwcap_P & LOONGARCH_HWCAP_LSX)
 #  endif
 # endif