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LoongArch: Add glibc.cpu.hwcap support.

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Key Points:
1. On lasx & lsx platforms, We must use _dl_runtime_{profile, resolve}_{lsx, lasx}
   to save vector registers.
2. Via "tunables", users can choose str/mem_{lasx,lsx,unaligned} functions with
   `export GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,...`.
   Note: glibc.cpu.hwcaps doesn't affect _dl_runtime_{profile, resolve}_{lsx, lasx}
   selection.

Usage Notes:
1. Only valid inputs: LASX, LSX, UAL. Case-sensitive, comma-separated, no spaces.
2. Example: `export GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,UAL` turns on LASX & UAL.
   Unmentioned features turn off. With default ifunc: lasx > lsx > unaligned >
   aligned > generic, effect is: lasx > unaligned > aligned > generic; lsx off.
3. Incorrect GLIBC_TUNABLES settings will show error messages.
   For example: On lsx platforms, you cannot enable lasx features. If you do
   that, you will get error messages.
4. Valid input examples:
   - GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX: lasx > aligned > generic.
   - GLIBC_TUNABLES=glibc.cpu.hwcaps=LSX,UAL: lsx > unaligned > aligned > generic.
   - GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,UAL,LASX,UAL,LSX,LASX,UAL: Repetitions
     allowed but not recommended. Results in: lasx > lsx > unaligned > aligned >
     generic.
This commit is contained in:
caiyinyu
2023-09-15 17:35:19 +08:00
parent 5bc9b3a1f6
commit a53451559d
11 changed files with 329 additions and 8 deletions
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18
sysdeps/unix/sysv/linux/loongarch/cpu-features.h
View File

@@ -19,13 +19,23 @@
#ifndef _CPU_FEATURES_LOONGARCH64_H
#define _CPU_FEATURES_LOONGARCH64_H
#include <stdint.h>
#include <sys/auxv.h>
#define SUPPORT_UAL (GLRO (dl_hwcap) & HWCAP_LOONGARCH_UAL)
#define SUPPORT_LSX (GLRO (dl_hwcap) & HWCAP_LOONGARCH_LSX)
#define SUPPORT_LASX (GLRO (dl_hwcap) & HWCAP_LOONGARCH_LASX)
struct cpu_features
{
uint64_t hwcap;
};
/* Get a pointer to the CPU features structure. */
extern const struct cpu_features *_dl_larch_get_cpu_features (void)
__attribute__ ((pure));
#define SUPPORT_UAL (GLRO (dl_larch_cpu_features).hwcap & HWCAP_LOONGARCH_UAL)
#define SUPPORT_LSX (GLRO (dl_larch_cpu_features).hwcap & HWCAP_LOONGARCH_LSX)
#define SUPPORT_LASX (GLRO (dl_larch_cpu_features).hwcap & HWCAP_LOONGARCH_LASX)
#define RTLD_SUPPORT_LSX (GLRO (dl_hwcap) & HWCAP_LOONGARCH_LSX)
#define RTLD_SUPPORT_LASX (GLRO (dl_hwcap) & HWCAP_LOONGARCH_LASX)
#define INIT_ARCH()
#endif /* _CPU_FEATURES_LOONGARCH64_H */