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ee7f4c54e1
This patch adds a new feature for powerpc. In order to get faster
access to the HWCAP3/HWCAP4 masks, similar to HWCAP/HWCAP2 (i.e. for
implementing __builtin_cpu_supports() in GCC) without the overhead of
reading them from the auxiliary vector, we now reserve space for them
in the TCB.
Suggested-by: Peter Bergner <bergner@linux.ibm.com>
Reviewed-by: Peter Bergner <bergner@linux.ibm.com>
(cherry picked from commit 3ab9b88e2a)
120 lines
3.5 KiB
C
120 lines
3.5 KiB
C
/* Copyright (C) 1998-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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<https://www.gnu.org/licenses/>. */
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#include <stdlib.h>
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#include <unistd.h>
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#include <ldsodefs.h>
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#include <sysdep.h>
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#ifndef SHARED
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#include <hwcapinfo.h>
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#endif
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#if ENABLE_STATIC_PIE && !defined SHARED
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/* For elf_machine_load_address. */
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#include <dl-machine.h>
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#endif
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/* The main work is done in the generic function. */
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#define LIBC_START_MAIN generic_start_main
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#define LIBC_START_DISABLE_INLINE
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#define LIBC_START_MAIN_AUXVEC_ARG
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#define MAIN_AUXVEC_ARG
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#define INIT_MAIN_ARGS
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#include <csu/libc-start.c>
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struct startup_info
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{
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void *sda_base;
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int (*main) (int, char **, char **, void *);
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int (*init) (int, char **, char **, void *);
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void (*fini) (void);
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};
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int
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__libc_start_main_impl (int argc, char **argv,
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char **ev,
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ElfW (auxv_t) * auxvec,
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void (*rtld_fini) (void),
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struct startup_info *stinfo,
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char **stack_on_entry)
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{
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/* the PPC SVR4 ABI says that the top thing on the stack will
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be a NULL pointer, so if not we assume that we're being called
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as a statically-linked program by Linux... */
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if (*stack_on_entry != NULL)
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{
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char **temp;
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/* ...in which case, we have argc as the top thing on the
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stack, followed by argv (NULL-terminated), envp (likewise),
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and the auxiliary vector. */
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/* 32/64-bit agnostic load from stack */
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argc = *(long int *) stack_on_entry;
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argv = stack_on_entry + 1;
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ev = argv + argc + 1;
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#ifdef HAVE_AUX_VECTOR
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temp = ev;
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while (*temp != NULL)
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++temp;
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auxvec = (ElfW (auxv_t) *)++ temp;
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#endif
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rtld_fini = NULL;
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}
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for (ElfW (auxv_t) * av = auxvec; av->a_type != AT_NULL; ++av)
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switch (av->a_type)
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{
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/* For the static case, we also need _dl_hwcap, _dl_hwcap2 and
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_dl_platform, so we can call
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__tcb_parse_hwcap_and_convert_at_platform (). */
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#ifndef SHARED
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case AT_HWCAP:
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_dl_hwcap = (unsigned long int) av->a_un.a_val;
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break;
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case AT_HWCAP2:
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_dl_hwcap2 = (unsigned long int) av->a_un.a_val;
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break;
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case AT_HWCAP3:
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_dl_hwcap3 = (unsigned long int) av->a_un.a_val;
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break;
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case AT_HWCAP4:
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_dl_hwcap4 = (unsigned long int) av->a_un.a_val;
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break;
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case AT_PLATFORM:
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_dl_platform = (void *) av->a_un.a_val;
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break;
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#endif
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}
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/* Initialize hwcap/hwcap2 and platform data so it can be copied to
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the TCB later in __libc_setup_tls (). (static case only). */
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#ifndef SHARED
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__tcb_parse_hwcap_and_convert_at_platform ();
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#endif
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void *stmain = stinfo->main;
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#if ENABLE_STATIC_PIE && !defined SHARED
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struct link_map *map = _dl_get_dl_main_map ();
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if (!map->l_relocated)
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stmain = (char *) stmain + elf_machine_load_address ();
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#endif
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return generic_start_main (stmain, argc, argv, auxvec,
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NULL, NULL, rtld_fini,
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stack_on_entry);
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}
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DEFINE_LIBC_START_MAIN_VERSION
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