Detection of hadware feature => please do not use signal

Bastien Roucariès <rouca@debian.org>

From: Bastien Roucariès <rouca@debian.org>

To: pgsql-bugs@lists.postgresql.org

Date: 2024-10-31T15:41:24Z

Lists: pgsql-bugs

Hi,

On debian side we will like to avoid use of sigill to detect feature.

https://sources.debian.org/src/postgresql-17/17.0-1/src/port/pg_crc32c_armv8_choose.c/#L55

is really bad.

Could you use the canonical way under linux

#include <sys/auxv.h>
#include <asm/hwcap.h>

 #if defined(__aarch64__)
   return !(getauxval(AT_HWCAP) &  HWCAP_CRC32);
 #else
   return !(getauxval(AT_HWCAP2) & HWCAP2_CRC32);
 #endif

Thanks

Rouca

Commits

Update configure probes for CFLAGS needed for ARM CRC instructions.
- e266a0ed67d2 17.3 landed
- 851c6ff18fd3 15.11 landed
- 5980f1884fc9 18.0 landed
- 32057a0f791e 13.19 landed
- 2fc0199a5015 14.16 landed
- 1f4aadec41b8 16.7 landed
Support runtime CRC feature probing on NetBSD/ARM using sysctl().
- 4570b22666dd 18.0 landed
Use auxv to check for CRC32 instructions on ARM.
- aac831cafa6f 18.0 landed
Improve our method for probing the availability of ARM CRC instructions.
- 1c72ec6f4989 11.0 cited