glibc/elf/dl-hwcaps.c

217 lines
6.9 KiB
C
Raw Normal View History

/* Hardware capability support for run-time dynamic loader.
Copyright (C) 2012-2024 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
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 13:40:42 +08:00
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <elf.h>
#include <errno.h>
#include <libintl.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <dl-procinfo.h>
#include <dl-hwcaps.h>
/* This is the result of counting the substrings in a colon-separated
hwcaps string. */
struct hwcaps_counts
{
/* Number of substrings. */
size_t count;
/* Sum of the individual substring lengths (without separators or
null terminators). */
size_t total_length;
/* Maximum length of an individual substring. */
size_t maximum_length;
};
/* Update *COUNTS according to the contents of HWCAPS. Skip over
entries whose bit is not set in MASK. */
static void
update_hwcaps_counts (struct hwcaps_counts *counts, const char *hwcaps,
uint32_t bitmask, const char *mask)
{
struct dl_hwcaps_split_masked sp;
_dl_hwcaps_split_masked_init (&sp, hwcaps, bitmask, mask);
while (_dl_hwcaps_split_masked (&sp))
{
++counts->count;
counts->total_length += sp.split.length;
if (sp.split.length > counts->maximum_length)
counts->maximum_length = sp.split.length;
}
}
/* State for copy_hwcaps. Must be initialized to point to
the storage areas for the array and the strings themselves. */
struct copy_hwcaps
{
struct r_strlenpair *next_pair;
char *next_string;
};
/* Copy HWCAPS into the string pairs and strings, advancing *TARGET.
Skip over entries whose bit is not set in MASK. */
static void
copy_hwcaps (struct copy_hwcaps *target, const char *hwcaps,
uint32_t bitmask, const char *mask)
{
struct dl_hwcaps_split_masked sp;
_dl_hwcaps_split_masked_init (&sp, hwcaps, bitmask, mask);
while (_dl_hwcaps_split_masked (&sp))
{
target->next_pair->str = target->next_string;
char *slash = __mempcpy (__mempcpy (target->next_string,
GLIBC_HWCAPS_PREFIX,
strlen (GLIBC_HWCAPS_PREFIX)),
sp.split.segment, sp.split.length);
*slash = '/';
target->next_pair->len
= strlen (GLIBC_HWCAPS_PREFIX) + sp.split.length + 1;
++target->next_pair;
target->next_string = slash + 1;
}
}
struct dl_hwcaps_priority *_dl_hwcaps_priorities;
uint32_t _dl_hwcaps_priorities_length;
/* Allocate _dl_hwcaps_priorities and fill it with data. */
static void
compute_priorities (size_t total_count, const char *prepend,
uint32_t bitmask, const char *mask)
{
_dl_hwcaps_priorities = malloc (total_count
* sizeof (*_dl_hwcaps_priorities));
if (_dl_hwcaps_priorities == NULL)
_dl_signal_error (ENOMEM, NULL, NULL,
N_("cannot create HWCAP priorities"));
_dl_hwcaps_priorities_length = total_count;
/* First the prepended subdirectories. */
size_t i = 0;
{
struct dl_hwcaps_split sp;
_dl_hwcaps_split_init (&sp, prepend);
while (_dl_hwcaps_split (&sp))
{
_dl_hwcaps_priorities[i].name = sp.segment;
_dl_hwcaps_priorities[i].name_length = sp.length;
_dl_hwcaps_priorities[i].priority = i + 1;
++i;
}
}
/* Then the built-in subdirectories that are actually active. */
{
struct dl_hwcaps_split_masked sp;
_dl_hwcaps_split_masked_init (&sp, _dl_hwcaps_subdirs, bitmask, mask);
while (_dl_hwcaps_split_masked (&sp))
{
_dl_hwcaps_priorities[i].name = sp.split.segment;
_dl_hwcaps_priorities[i].name_length = sp.split.length;
_dl_hwcaps_priorities[i].priority = i + 1;
++i;
}
}
assert (i == total_count);
}
/* Sort the _dl_hwcaps_priorities array by name. */
static void
sort_priorities_by_name (void)
{
/* Insertion sort. There is no need to link qsort into the dynamic
loader for such a short array. */
for (size_t i = 1; i < _dl_hwcaps_priorities_length; ++i)
for (size_t j = i; j > 0; --j)
{
struct dl_hwcaps_priority *previous = _dl_hwcaps_priorities + j - 1;
struct dl_hwcaps_priority *current = _dl_hwcaps_priorities + j;
/* Bail out if current is greater or equal to the previous
value. */
uint32_t to_compare;
if (current->name_length < previous->name_length)
to_compare = current->name_length;
else
to_compare = previous->name_length;
int cmp = memcmp (current->name, previous->name, to_compare);
if (cmp > 0
|| (cmp == 0 && current->name_length >= previous->name_length))
break;
/* Swap *previous and *current. */
struct dl_hwcaps_priority tmp = *previous;
*previous = *current;
*current = tmp;
}
}
/* Return an array of useful/necessary hardware capability names. */
const struct r_strlenpair *
_dl_important_hwcaps (const char *glibc_hwcaps_prepend,
const char *glibc_hwcaps_mask,
size_t *sz, size_t *max_capstrlen)
{
/* glibc-hwcaps subdirectories. */
uint32_t hwcaps_subdirs_active = _dl_hwcaps_subdirs_active ();
struct hwcaps_counts hwcaps_counts = { 0, };
update_hwcaps_counts (&hwcaps_counts, glibc_hwcaps_prepend, -1, NULL);
update_hwcaps_counts (&hwcaps_counts, _dl_hwcaps_subdirs,
hwcaps_subdirs_active, glibc_hwcaps_mask);
compute_priorities (hwcaps_counts.count, glibc_hwcaps_prepend,
hwcaps_subdirs_active, glibc_hwcaps_mask);
sort_priorities_by_name ();
/* Each hwcaps subdirectory has a GLIBC_HWCAPS_PREFIX string prefix
and a "/" suffix once stored in the result. */
hwcaps_counts.maximum_length += strlen (GLIBC_HWCAPS_PREFIX) + 1;
size_t total = (hwcaps_counts.count * (strlen (GLIBC_HWCAPS_PREFIX) + 1)
+ hwcaps_counts.total_length);
*sz = hwcaps_counts.count + 1;
/* This is the overall result. */
struct r_strlenpair *overall_result
= malloc (*sz * sizeof (*overall_result) + total);
if (overall_result == NULL)
_dl_signal_error (ENOMEM, NULL, NULL,
N_("cannot create capability list"));
/* Fill in the glibc-hwcaps subdirectories. */
{
struct copy_hwcaps target;
target.next_pair = overall_result;
target.next_string = (char *) (overall_result + *sz);
copy_hwcaps (&target, glibc_hwcaps_prepend, -1, NULL);
copy_hwcaps (&target, _dl_hwcaps_subdirs,
hwcaps_subdirs_active, glibc_hwcaps_mask);
/* Append an empty entry for the base directory itself. */
target.next_pair->str = target.next_string;
target.next_pair->len = 0;
}
/* The maximum string length. */
*max_capstrlen = hwcaps_counts.maximum_length;
return overall_result;
}