diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/include/pg_config.h.in | 3 | ||||
| -rw-r--r-- | src/port/pg_crc32c_armv8_choose.c | 33 |
2 files changed, 25 insertions, 11 deletions
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index f3620231a71..9411f485121 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -239,9 +239,6 @@ /* Define to 1 if you have the `getaddrinfo' function. */ #undef HAVE_GETADDRINFO -/* Define to 1 if you have the `getauxval' function. */ -#undef HAVE_GETAUXVAL - /* Define to 1 if you have the `gethostbyname_r' function. */ #undef HAVE_GETHOSTBYNAME_R diff --git a/src/port/pg_crc32c_armv8_choose.c b/src/port/pg_crc32c_armv8_choose.c index f21a8243e9a..d0d3a3da78e 100644 --- a/src/port/pg_crc32c_armv8_choose.c +++ b/src/port/pg_crc32c_armv8_choose.c @@ -8,10 +8,6 @@ * computation. Otherwise, fall back to the pure software implementation * (slicing-by-8). * - * XXX: The glibc-specific getauxval() function, with the HWCAP_CRC32 - * flag, is used to determine if the CRC Extension is available on the - * current platform. Is there a more portable way to determine that? - * * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * @@ -24,17 +20,38 @@ #include "c.h" -#include <sys/auxv.h> -#include <asm/hwcap.h> +#include <setjmp.h> +#include "libpq/pqsignal.h" #include "port/pg_crc32c.h" + +static sigjmp_buf illegal_instruction_jump; + +/* + * Probe by trying to execute pg_comp_crc32c_armv8(). If the instruction + * isn't available, we expect to get SIGILL, which we can trap. + */ +static void +illegal_instruction_handler(int signo) +{ + siglongjmp(illegal_instruction_jump, 1); +} + static bool pg_crc32c_armv8_available(void) { - unsigned long auxv = getauxval(AT_HWCAP); + uint64 data = 42; + bool result; + + pqsignal(SIGILL, illegal_instruction_handler); + if (sigsetjmp(illegal_instruction_jump, 1) == 0) + result = (pg_comp_crc32c_armv8(0, &data, sizeof(data)) == 0xdd439b0d); + else + result = false; + pqsignal(SIGILL, SIG_DFL); - return (auxv & HWCAP_CRC32) != 0; + return result; } /* |