LoongArch: Add glibc.cpu.hwcap support.

The current IFUNC selection is always using the most recent
features which are available via AT_HWCAP.  But in
some scenarios it is useful to adjust this selection.

The environment variable:

GLIBC_TUNABLES=glibc.cpu.hwcaps=-xxx,yyy,zzz,....

can be used to enable HWCAP feature yyy, disable HWCAP feature xxx,
where the feature name is case-sensitive and has to match the ones
used in sysdeps/loongarch/cpu-tunables.c.

Signed-off-by: caiyinyu <caiyinyu@loongson.cn>
This commit is contained in:
caiyinyu 2023-09-15 17:35:19 +08:00
parent f4724843ad
commit 095067efdf
13 changed files with 475 additions and 9 deletions

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@ -525,7 +525,10 @@ a CPU arch-level like @code{z13} instead of single HWCAP and STFLE features.
On powerpc, the supported HWCAP and HWCAP2 features can be found in
@code{sysdeps/powerpc/dl-procinfo.c}.
This tunable is specific to i386, x86-64, s390x and powerpc.
On loongarch, the supported HWCAP features can be found in
@code{sysdeps/loongarch/cpu-tunables.c}.
This tunable is specific to i386, x86-64, s390x, powerpc and loongarch.
@end deftp
@deftp Tunable glibc.cpu.cached_memopt

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@ -1,11 +1,23 @@
ifeq ($(subdir),misc)
sysdep_headers += sys/asm.h
tests += \
tst-hwcap-tunables \
# tests
tst-hwcap-tunables-ARGS = -- $(host-test-program-cmd)
endif
ifeq ($(subdir),elf)
gen-as-const-headers += dl-link.sym
endif
ifeq ($(subdir),elf)
sysdep-dl-routines += \
dl-get-cpu-features \
# sysdep-dl-routines
endif
# LoongArch's assembler also needs to know about PIC as it changes the
# definition of some assembler macros.
ASFLAGS-.os += $(pic-ccflag)

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@ -0,0 +1,87 @@
/* LoongArch CPU feature tuning.
This file is part of the GNU C Library.
Copyright (C) 2024 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdbool.h>
#include <stdint.h>
#include <unistd.h> /* Get STDOUT_FILENO for _dl_printf. */
#include <elf/dl-tunables.h>
#include <string.h>
#include <cpu-features.h>
#include <ldsodefs.h>
#include <sys/auxv.h>
#include <dl-tunables-parse.h>
#include <dl-symbol-redir-ifunc.h>
#define CHECK_GLIBC_IFUNC_CPU(f, name, len) \
_Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
if (tunable_str_comma_strcmp_cte (&f, #name)) \
{ \
if (f.disable) \
GLRO(dl_larch_cpu_features).hwcap &= (~HWCAP_LOONGARCH_##name); \
else \
GLRO(dl_larch_cpu_features).hwcap |= HWCAP_LOONGARCH_##name; \
break; \
}
attribute_hidden void
TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
{
/* The current IFUNC selection is based on microbenchmarks in glibc.
It should give the best performance for most workloads. But other
choices may have better performance for a particular workload or on
the hardware which wasn't available when the selection was made.
The environment variable:
GLIBC_TUNABLES=glibc.cpu.hwcaps=-xxx,yyy,-zzz,....
can be used to enable CPU/ARCH feature yyy, disable CPU/ARCH feature
yyy and zzz, where the feature name is case-sensitive and has to
match the ones in cpu-features.h. It can be used by glibc developers
to tune for a new processor or override the IFUNC selection to
improve performance for a particular workload.
NOTE: the IFUNC selection may change over time. Please check all
multiarch implementations when experimenting. */
struct tunable_str_comma_state_t ts;
tunable_str_comma_init (&ts, valp);
struct tunable_str_comma_t n;
while (tunable_str_comma_next (&ts, &n))
{
switch (n.len)
{
default:
break;
case 3:
{
CHECK_GLIBC_IFUNC_CPU (n, LSX, 3);
CHECK_GLIBC_IFUNC_CPU (n, UAL, 3);
}
break;
case 4:
{
CHECK_GLIBC_IFUNC_CPU (n, LASX, 4);
}
break;
}
}
/* Ensure that the user has not enabled any unsupported features. */
GLRO(dl_larch_cpu_features).hwcap &= GLRO(dl_hwcap);
}

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@ -0,0 +1,25 @@
/* Define _dl_larch_get_cpu_features.
Copyright (C) 2024 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <ldsodefs.h>
const struct cpu_features *
_dl_larch_get_cpu_features (void)
{
return &GLRO(dl_larch_cpu_features);
}

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@ -29,6 +29,8 @@
#include <dl-static-tls.h>
#include <dl-machine-rel.h>
#include <cpu-features.c>
#ifndef _RTLD_PROLOGUE
# define _RTLD_PROLOGUE(entry) \
".globl\t" __STRING (entry) "\n\t" \
@ -53,6 +55,23 @@
#define ELF_MACHINE_NO_REL 1
#define ELF_MACHINE_NO_RELA 0
#define DL_PLATFORM_INIT dl_platform_init ()
static inline void __attribute__ ((unused))
dl_platform_init (void)
{
if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
/* Avoid an empty string which would disturb us. */
GLRO(dl_platform) = NULL;
#ifdef SHARED
/* init_cpu_features has been called early from __libc_start_main in
static executable. */
init_cpu_features (&GLRO(dl_larch_cpu_features));
#endif
}
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int
elf_machine_matches_host (const ElfW (Ehdr) *ehdr)
@ -290,10 +309,10 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
#ifdef SHARED
if (profile != 0)
{
# if !defined __loongarch_soft_float
if (SUPPORT_LASX)
#if !defined __loongarch_soft_float
if (RTLD_SUPPORT_LASX)
gotplt[0] = (ElfW(Addr)) &_dl_runtime_profile_lasx;
else if (SUPPORT_LSX)
else if (RTLD_SUPPORT_LSX)
gotplt[0] = (ElfW(Addr)) &_dl_runtime_profile_lsx;
else
# endif
@ -312,9 +331,9 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
indicated by the offset on the stack, and then jump to
the resolved address. */
#if !defined __loongarch_soft_float
if (SUPPORT_LASX)
if (RTLD_SUPPORT_LASX)
gotplt[0] = (ElfW(Addr)) &_dl_runtime_resolve_lasx;
else if (SUPPORT_LSX)
else if (RTLD_SUPPORT_LSX)
gotplt[0] = (ElfW(Addr)) &_dl_runtime_resolve_lsx;
else
#endif

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@ -0,0 +1,25 @@
# LoongArch specific tunables.
# Copyright (C) 2024 Free Software Foundation, Inc.
# This file is part of the GNU C Library.
# The GNU C Library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# The GNU C Library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public
# License along with the GNU C Library; if not, see
# <http://www.gnu.org/licenses/>.
glibc {
cpu {
hwcaps {
type: STRING
}
}
}

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@ -19,6 +19,9 @@
#ifndef _DL_IFUNC_GENERIC_H
#define _DL_IFUNC_GENERIC_H
#ifndef SHARED
asm ("memset = __memset_aligned");
asm ("memcmp = __memcmp_aligned");
#endif
#endif

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@ -0,0 +1,136 @@
/* Tests for LoongArch GLIBC_TUNABLES=glibc.cpu.hwcaps filter.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <array_length.h>
#include <getopt.h>
#include <ifunc-impl-list.h>
#include <spawn.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/support.h>
#include <support/xunistd.h>
#include <sys/auxv.h>
#include <sys/wait.h>
/* Nonzero if the program gets called via `exec'. */
#define CMDLINE_OPTIONS \
{ "restart", no_argument, &restart, 1 }, \
{ "enable", no_argument, &enable, 1 },
static int restart;
static int enable;
/* Hold the four initial argument used to respawn the process, plus the extra
'--direct', '--restart', and the function to check. */
static char *spargs[9];
static int fc;
/* Called on process re-execution. */
_Noreturn static void
handle_restart (int argc, char *argv[])
{
TEST_VERIFY_EXIT (argc == 1);
const char *funcname = argv[0];
struct libc_ifunc_impl impls[32];
int cnt = __libc_ifunc_impl_list ("memcpy", impls, array_length (impls));
if (cnt == 0)
_exit (EXIT_SUCCESS);
TEST_VERIFY_EXIT (cnt >= 1);
for (int i = 0; i < cnt; i++)
{
if (strcmp (impls[i].name, funcname) == 0)
{
if (enable && impls[i].usable != true)
FAIL_EXIT1 ("FAIL: %s ifunc selection is not enabled.\n", funcname);
else if (!enable && impls[i].usable != false)
FAIL_EXIT1 ("FAIL: %s ifunc selection is not disabled.\n", funcname);
break;
}
}
_exit (EXIT_SUCCESS);
}
static void
run_test (const char *filter, const char *funcname, int disable)
{
if (disable)
printf ("info: checking filter %s (expect %s ifunc "
"selection to be disabled)\n", filter, funcname);
else
{
printf ("info: checking filter %s (expect %s ifunc "
"selection to be enabled)\n", filter, funcname);
spargs[fc++] = (char *) "--enable";
}
char *tunable = xasprintf ("GLIBC_TUNABLES=glibc.cpu.hwcaps=%s", filter);
char *const newenvs[] = { (char*) tunable, NULL };
spargs[fc] = (char *) funcname;
pid_t pid;
TEST_COMPARE (posix_spawn (&pid, spargs[0], NULL, NULL, spargs, newenvs), 0);
int status;
TEST_COMPARE (xwaitpid (pid, &status, 0), pid);
TEST_VERIFY (WIFEXITED (status));
TEST_VERIFY (!WIFSIGNALED (status));
TEST_COMPARE (WEXITSTATUS (status), 0);
if (!disable)
fc--;
free (tunable);
}
static int
do_test (int argc, char *argv[])
{
if (restart)
handle_restart (argc - 1, &argv[1]);
TEST_VERIFY_EXIT (argc == 2 || argc == 5);
int i;
for (i = 0; i < argc - 1; i++)
spargs[i] = argv[i + 1];
spargs[i++] = (char *) "--direct";
spargs[i++] = (char *) "--restart";
fc = i++;
spargs[i] = NULL;
unsigned long int hwcap = getauxval (AT_HWCAP);
if (hwcap & HWCAP_LOONGARCH_LASX)
run_test ("-LASX", "__memcpy_lasx", 1);
if (hwcap & HWCAP_LOONGARCH_LSX)
run_test ("-LSX", "__memcpy_lsx", 1);
if (hwcap & HWCAP_LOONGARCH_UAL)
run_test ("-UAL", "__memcpy_unaligned", 1);
/* __memcpy_aligned is the default ifunc selection and will be
* always enabled. */
run_test ("-LASX,-LSX,-UAL", "__memcpy_aligned", 0);
run_test ("-LASX,-LSX", "__memcpy_aligned", 0);
run_test ("-LASX", "__memcpy_aligned", 0);
return 0;
}
#define TEST_FUNCTION_ARGV do_test
#include <support/test-driver.c>

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@ -0,0 +1,30 @@
/* Initialize CPU feature data. LoongArch64 version.
This file is part of the GNU C Library.
Copyright (C) 2024 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <cpu-features.h>
#include <elf/dl-hwcaps.h>
#include <elf/dl-tunables.h>
extern void TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *) attribute_hidden;
static inline void
init_cpu_features (struct cpu_features *cpu_features)
{
GLRO(dl_larch_cpu_features).hwcap = GLRO(dl_hwcap);
TUNABLE_GET (glibc, cpu, hwcaps, tunable_val_t *,
TUNABLE_CALLBACK (set_hwcaps));
}

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@ -19,12 +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 */

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@ -0,0 +1,60 @@
/* Data for LoongArch64 version of processor capability information.
Linux version.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* If anything should be added here check whether the size of each string
is still ok with the given array size.
All the #ifdefs in the definitions are quite irritating but
necessary if we want to avoid duplicating the information. There
are three different modes:
- PROCINFO_DECL is defined. This means we are only interested in
declarations.
- PROCINFO_DECL is not defined:
+ if SHARED is defined the file is included in an array
initializer. The .element = { ... } syntax is needed.
+ if SHARED is not defined a normal array initialization is
needed.
*/
#ifndef PROCINFO_CLASS
# define PROCINFO_CLASS
#endif
#if !IS_IN (ldconfig)
# if !defined PROCINFO_DECL && defined SHARED
._dl_larch_cpu_features
# else
PROCINFO_CLASS struct cpu_features _dl_larch_cpu_features
# endif
# ifndef PROCINFO_DECL
= { }
# endif
# if !defined SHARED || defined PROCINFO_DECL
;
# else
,
# endif
#endif
#undef PROCINFO_DECL
#undef PROCINFO_CLASS

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@ -0,0 +1,21 @@
/* Operating system support for run-time dynamic linker. LoongArch version.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <config.h>
#include <sysdeps/loongarch/cpu-tunables.c>
#include <sysdeps/unix/sysv/linux/dl-sysdep.c>

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@ -0,0 +1,34 @@
/* Override csu/libc-start.c on LoongArch64.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef SHARED
/* Mark symbols hidden in static PIE for early self relocation to work. */
#if BUILD_PIE_DEFAULT
# pragma GCC visibility push (hidden)
#endif
#include <ldsodefs.h>
#include <cpu-features.c>
extern struct cpu_features _dl_larch_cpu_features;
#define ARCH_INIT_CPU_FEATURES() init_cpu_features (&_dl_larch_cpu_features)
#endif
#include <csu/libc-start.c>