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a53451559d
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.
89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
/* LoongArch CPU feature tuning.
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This file is part of the GNU C Library.
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Copyright (C) 2023 Free Software Foundation, Inc.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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# include <stdbool.h>
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# include <stdint.h>
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# include <unistd.h> /* Get STDOUT_FILENO for _dl_printf. */
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# include <elf/dl-tunables.h>
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# include <string.h>
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# include <cpu-features.h>
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# include <ldsodefs.h>
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# include <sys/auxv.h>
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# define HWCAP_LOONGARCH_IFUNC \
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(HWCAP_LOONGARCH_UAL | HWCAP_LOONGARCH_LSX | HWCAP_LOONGARCH_LASX)
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# define CHECK_GLIBC_IFUNC_CPU_OFF(f, name, len) \
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_Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
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if (!memcmp (f, #name, len) && \
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(GLRO (dl_hwcap) & HWCAP_LOONGARCH_##name)) \
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{ \
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hwcap |= (HWCAP_LOONGARCH_##name | (~HWCAP_LOONGARCH_IFUNC)); \
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break; \
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} \
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attribute_hidden
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void
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TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
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{
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const char *p = valp->strval;
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size_t len;
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unsigned long hwcap = 0;
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const char *c;
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do {
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for (c = p; *c != ','; c++)
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if (*c == '\0')
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break;
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len = c - p;
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switch(len)
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{
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default:
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_dl_fatal_printf (
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"The valid values of glibc.cpu.hwcaps is UAL, LASX, LSX!!\n"
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);
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break;
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case 3:
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (p, LSX, 3);
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CHECK_GLIBC_IFUNC_CPU_OFF (p, UAL, 3);
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_dl_fatal_printf (
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"Some features are invalid or not supported on this machine!!\n"
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"The valid values of glibc.cpu.hwcaps is UAL, LASX, LSX!!\n"
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);
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}
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break;
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case 4:
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (p, LASX, 4);
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_dl_fatal_printf (
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"Some features are invalid or not supported on this machine!!\n"
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"The valid values of glibc.cpu.hwcaps is UAL, LASX, LSX!!\n"
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);
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}
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break;
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}
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p += len + 1;
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}
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while (*c != '\0');
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GLRO (dl_larch_cpu_features).hwcap &= hwcap;
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}
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