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04277e02d7
* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
531 lines
16 KiB
C
531 lines
16 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. Alpha version.
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Copyright (C) 1996-2019 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Richard Henderson <rth@tamu.edu>.
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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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/* This was written in the absence of an ABI -- don't expect
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it to remain unchanged. */
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#ifndef dl_machine_h
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#define dl_machine_h 1
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#define ELF_MACHINE_NAME "alpha"
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#include <string.h>
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/* Mask identifying addresses reserved for the user program,
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where the dynamic linker should not map anything. */
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#define ELF_MACHINE_USER_ADDRESS_MASK 0x120000000UL
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/* Translate a processor specific dynamic tag to the index in l_info array. */
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#define DT_ALPHA(x) (DT_ALPHA_##x - DT_LOPROC + DT_NUM)
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/* Return nonzero iff ELF header is compatible with the running host. */
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static inline int
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elf_machine_matches_host (const Elf64_Ehdr *ehdr)
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{
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return ehdr->e_machine == EM_ALPHA;
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}
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/* Return the link-time address of _DYNAMIC. The multiple-got-capable
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linker no longer allocates the first .got entry for this. But not to
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worry, no special tricks are needed. */
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static inline Elf64_Addr
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elf_machine_dynamic (void)
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{
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#ifndef NO_AXP_MULTI_GOT_LD
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return (Elf64_Addr) &_DYNAMIC;
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#else
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register Elf64_Addr *gp __asm__ ("$29");
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return gp[-4096];
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#endif
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}
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/* Return the run-time load address of the shared object. */
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static inline Elf64_Addr
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elf_machine_load_address (void)
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{
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/* This relies on the compiler using gp-relative addresses for static symbols. */
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static void *dot = ˙
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return (void *)&dot - dot;
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}
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/* Set up the loaded object described by L so its unrelocated PLT
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entries will jump to the on-demand fixup code in dl-runtime.c. */
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static inline int
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elf_machine_runtime_setup (struct link_map *map, int lazy, int profile)
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{
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extern char _dl_runtime_resolve_new[] attribute_hidden;
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extern char _dl_runtime_profile_new[] attribute_hidden;
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extern char _dl_runtime_resolve_old[] attribute_hidden;
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extern char _dl_runtime_profile_old[] attribute_hidden;
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struct pltgot {
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char *resolve;
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struct link_map *link;
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};
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struct pltgot *pg;
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long secureplt;
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char *resolve;
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if (map->l_info[DT_JMPREL] == 0 || !lazy)
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return lazy;
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/* Check to see if we're using the read-only plt form. */
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secureplt = map->l_info[DT_ALPHA(PLTRO)] != 0;
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/* If the binary uses the read-only secure plt format, PG points to
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the .got.plt section, which is the right place for ld.so to place
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its hooks. Otherwise, PG is currently pointing at the start of
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the plt; the hooks go at offset 16. */
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pg = (struct pltgot *) D_PTR (map, l_info[DT_PLTGOT]);
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pg += !secureplt;
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/* This function will be called to perform the relocation. They're
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not declared as functions to convince the compiler to use gp
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relative relocations for them. */
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if (secureplt)
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resolve = _dl_runtime_resolve_new;
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else
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resolve = _dl_runtime_resolve_old;
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if (__builtin_expect (profile, 0))
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{
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if (secureplt)
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resolve = _dl_runtime_profile_new;
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else
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resolve = _dl_runtime_profile_old;
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if (GLRO(dl_profile) && _dl_name_match_p (GLRO(dl_profile), map))
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{
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/* This is the object we are looking for. Say that we really
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want profiling and the timers are started. */
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GL(dl_profile_map) = map;
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}
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}
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pg->resolve = resolve;
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pg->link = map;
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return lazy;
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}
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/* Initial entry point code for the dynamic linker.
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The C function `_dl_start' is the real entry point;
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its return value is the user program's entry point. */
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#define RTLD_START asm ("\
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.section .text \n\
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.set at \n\
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.globl _start \n\
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.ent _start \n\
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_start: \n\
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.frame $31,0,$31,0 \n\
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br $gp, 0f \n\
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0: ldgp $gp, 0($gp) \n\
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.prologue 0 \n\
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/* Pass pointer to argument block to _dl_start. */ \n\
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mov $sp, $16 \n\
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bsr $26, _dl_start !samegp \n\
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.end _start \n\
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/* FALLTHRU */ \n\
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.globl _dl_start_user \n\
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.ent _dl_start_user \n\
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_dl_start_user: \n\
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.frame $31,0,$31,0 \n\
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.prologue 0 \n\
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/* Save the user entry point address in s0. */ \n\
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mov $0, $9 \n\
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/* See if we were run as a command with the executable \n\
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file name as an extra leading argument. */ \n\
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ldah $1, _dl_skip_args($gp) !gprelhigh \n\
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ldl $1, _dl_skip_args($1) !gprellow \n\
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bne $1, $fixup_stack \n\
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$fixup_stack_ret: \n\
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/* The special initializer gets called with the stack \n\
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just as the application's entry point will see it; \n\
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it can switch stacks if it moves these contents \n\
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over. */ \n\
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" RTLD_START_SPECIAL_INIT " \n\
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/* Call _dl_init(_dl_loaded, argc, argv, envp) to run \n\
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initializers. */ \n\
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ldah $16, _rtld_local($gp) !gprelhigh \n\
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ldq $16, _rtld_local($16) !gprellow \n\
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ldq $17, 0($sp) \n\
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lda $18, 8($sp) \n\
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s8addq $17, 8, $19 \n\
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addq $19, $18, $19 \n\
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bsr $26, _dl_init !samegp \n\
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/* Pass our finalizer function to the user in $0. */ \n\
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ldah $0, _dl_fini($gp) !gprelhigh \n\
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lda $0, _dl_fini($0) !gprellow \n\
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/* Jump to the user's entry point. */ \n\
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mov $9, $27 \n\
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jmp ($9) \n\
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$fixup_stack: \n\
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/* Adjust the stack pointer to skip _dl_skip_args words.\n\
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This involves copying everything down, since the \n\
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stack pointer must always be 16-byte aligned. */ \n\
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ldah $7, __GI__dl_argv($gp) !gprelhigh \n\
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ldq $2, 0($sp) \n\
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ldq $5, __GI__dl_argv($7) !gprellow \n\
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subq $31, $1, $6 \n\
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subq $2, $1, $2 \n\
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s8addq $6, $5, $5 \n\
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mov $sp, $4 \n\
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s8addq $1, $sp, $3 \n\
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stq $2, 0($sp) \n\
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stq $5, __GI__dl_argv($7) !gprellow \n\
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/* Copy down argv. */ \n\
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0: ldq $5, 8($3) \n\
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addq $4, 8, $4 \n\
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addq $3, 8, $3 \n\
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stq $5, 0($4) \n\
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bne $5, 0b \n\
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/* Copy down envp. */ \n\
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1: ldq $5, 8($3) \n\
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addq $4, 8, $4 \n\
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addq $3, 8, $3 \n\
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stq $5, 0($4) \n\
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bne $5, 1b \n\
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/* Copy down auxiliary table. */ \n\
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2: ldq $5, 8($3) \n\
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ldq $6, 16($3) \n\
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addq $4, 16, $4 \n\
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addq $3, 16, $3 \n\
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stq $5, -8($4) \n\
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stq $6, 0($4) \n\
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bne $5, 2b \n\
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br $fixup_stack_ret \n\
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.end _dl_start_user \n\
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.set noat \n\
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.previous");
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#ifndef RTLD_START_SPECIAL_INIT
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#define RTLD_START_SPECIAL_INIT /* nothing */
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#endif
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/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry
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or TLS variables, so undefined references should not be allowed
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to define the value.
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ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve
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to one of the main executable's symbols, as for a COPY reloc.
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This is unused on Alpha. */
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# define elf_machine_type_class(type) \
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(((type) == R_ALPHA_JMP_SLOT \
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|| (type) == R_ALPHA_DTPMOD64 \
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|| (type) == R_ALPHA_DTPREL64 \
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|| (type) == R_ALPHA_TPREL64) * ELF_RTYPE_CLASS_PLT)
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/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
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#define ELF_MACHINE_JMP_SLOT R_ALPHA_JMP_SLOT
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/* The alpha never uses Elf64_Rel relocations. */
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#define ELF_MACHINE_NO_REL 1
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#define ELF_MACHINE_NO_RELA 0
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/* We define an initialization functions. This is called very early in
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* _dl_sysdep_start. */
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#define DL_PLATFORM_INIT dl_platform_init ()
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static inline void __attribute__ ((unused))
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dl_platform_init (void)
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{
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if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
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/* Avoid an empty string which would disturb us. */
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GLRO(dl_platform) = NULL;
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}
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/* Fix up the instructions of a PLT entry to invoke the function
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rather than the dynamic linker. */
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static inline Elf64_Addr
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elf_machine_fixup_plt (struct link_map *map, lookup_t t,
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const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
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const Elf64_Rela *reloc,
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Elf64_Addr *got_addr, Elf64_Addr value)
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{
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const Elf64_Rela *rela_plt;
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Elf64_Word *plte;
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long int edisp;
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/* Store the value we are going to load. */
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*got_addr = value;
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/* If this binary uses the read-only secure plt format, we're done. */
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if (map->l_info[DT_ALPHA(PLTRO)])
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return value;
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/* Otherwise we have to modify the plt entry in place to do the branch. */
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/* Recover the PLT entry address by calculating reloc's index into the
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.rela.plt, and finding that entry in the .plt. */
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rela_plt = (const Elf64_Rela *) D_PTR (map, l_info[DT_JMPREL]);
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plte = (Elf64_Word *) (D_PTR (map, l_info[DT_PLTGOT]) + 32);
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plte += 3 * (reloc - rela_plt);
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/* Find the displacement from the plt entry to the function. */
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edisp = (long int) (value - (Elf64_Addr)&plte[3]) / 4;
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if (edisp >= -0x100000 && edisp < 0x100000)
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{
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/* If we are in range, use br to perfect branch prediction and
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elide the dependency on the address load. This case happens,
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e.g., when a shared library call is resolved to the same library. */
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int hi, lo;
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hi = value - (Elf64_Addr)&plte[0];
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lo = (short int) hi;
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hi = (hi - lo) >> 16;
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/* Emit "lda $27,lo($27)" */
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plte[1] = 0x237b0000 | (lo & 0xffff);
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/* Emit "br $31,function" */
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plte[2] = 0xc3e00000 | (edisp & 0x1fffff);
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/* Think about thread-safety -- the previous instructions must be
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committed to memory before the first is overwritten. */
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__asm__ __volatile__("wmb" : : : "memory");
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/* Emit "ldah $27,hi($27)" */
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plte[0] = 0x277b0000 | (hi & 0xffff);
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}
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else
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{
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/* Don't bother with the hint since we already know the hint is
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wrong. Eliding it prevents the wrong page from getting pulled
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into the cache. */
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int hi, lo;
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hi = (Elf64_Addr)got_addr - (Elf64_Addr)&plte[0];
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lo = (short)hi;
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hi = (hi - lo) >> 16;
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/* Emit "ldq $27,lo($27)" */
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plte[1] = 0xa77b0000 | (lo & 0xffff);
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/* Emit "jmp $31,($27)" */
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plte[2] = 0x6bfb0000;
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/* Think about thread-safety -- the previous instructions must be
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committed to memory before the first is overwritten. */
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__asm__ __volatile__("wmb" : : : "memory");
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/* Emit "ldah $27,hi($27)" */
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plte[0] = 0x277b0000 | (hi & 0xffff);
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}
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/* At this point, if we've been doing runtime resolution, Icache is dirty.
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This will be taken care of in _dl_runtime_resolve. If instead we are
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doing this as part of non-lazy startup relocation, that bit of code
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hasn't made it into Icache yet, so there's nothing to clean up. */
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return value;
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}
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/* Return the final value of a plt relocation. */
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static inline Elf64_Addr
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elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
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Elf64_Addr value)
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{
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return value + reloc->r_addend;
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}
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/* Names of the architecture-specific auditing callback functions. */
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#define ARCH_LA_PLTENTER alpha_gnu_pltenter
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#define ARCH_LA_PLTEXIT alpha_gnu_pltexit
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#endif /* !dl_machine_h */
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#ifdef RESOLVE_MAP
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/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
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MAP is the object containing the reloc. */
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auto inline void
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__attribute__ ((always_inline))
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elf_machine_rela (struct link_map *map,
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const Elf64_Rela *reloc,
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const Elf64_Sym *sym,
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const struct r_found_version *version,
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void *const reloc_addr_arg,
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int skip_ifunc)
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{
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Elf64_Addr *const reloc_addr = reloc_addr_arg;
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unsigned long int const r_type = ELF64_R_TYPE (reloc->r_info);
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#if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC && !defined SHARED
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/* This is defined in rtld.c, but nowhere in the static libc.a; make the
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reference weak so static programs can still link. This declaration
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cannot be done when compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP)
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because rtld.c contains the common defn for _dl_rtld_map, which is
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incompatible with a weak decl in the same file. */
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weak_extern (_dl_rtld_map);
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#endif
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/* We cannot use a switch here because we cannot locate the switch
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jump table until we've self-relocated. */
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#if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
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if (__builtin_expect (r_type == R_ALPHA_RELATIVE, 0))
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{
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# if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
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/* Already done in dynamic linker. */
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if (map != &GL(dl_rtld_map))
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# endif
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{
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/* XXX Make some timings. Maybe it's preferable to test for
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unaligned access and only do it the complex way if necessary. */
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Elf64_Addr reloc_addr_val;
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/* Load value without causing unaligned trap. */
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memcpy (&reloc_addr_val, reloc_addr_arg, 8);
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reloc_addr_val += map->l_addr;
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/* Store value without causing unaligned trap. */
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memcpy (reloc_addr_arg, &reloc_addr_val, 8);
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}
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}
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else
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#endif
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if (__builtin_expect (r_type == R_ALPHA_NONE, 0))
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return;
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else
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{
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struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
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Elf64_Addr sym_value;
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Elf64_Addr sym_raw_value;
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sym_raw_value = sym_value = reloc->r_addend;
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if (sym_map)
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{
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sym_raw_value += sym->st_value;
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sym_value += SYMBOL_ADDRESS (sym_map, sym, true);
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|
}
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if (r_type == R_ALPHA_GLOB_DAT)
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|
*reloc_addr = sym_value;
|
|
#ifdef RESOLVE_CONFLICT_FIND_MAP
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|
/* In .gnu.conflict section, R_ALPHA_JMP_SLOT relocations have
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|
R_ALPHA_JMP_SLOT in lower 8 bits and the remaining 24 bits
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|
are .rela.plt index. */
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else if ((r_type & 0xff) == R_ALPHA_JMP_SLOT)
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{
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/* elf_machine_fixup_plt needs the map reloc_addr points into,
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while in _dl_resolve_conflicts map is _dl_loaded. */
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RESOLVE_CONFLICT_FIND_MAP (map, reloc_addr);
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reloc = ((const Elf64_Rela *) D_PTR (map, l_info[DT_JMPREL]))
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+ (r_type >> 8);
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elf_machine_fixup_plt (map, 0, 0, 0, reloc, reloc_addr, sym_value);
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}
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#else
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else if (r_type == R_ALPHA_JMP_SLOT)
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elf_machine_fixup_plt (map, 0, 0, 0, reloc, reloc_addr, sym_value);
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#endif
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|
#ifndef RTLD_BOOTSTRAP
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else if (r_type == R_ALPHA_REFQUAD)
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{
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/* Store value without causing unaligned trap. */
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|
memcpy (reloc_addr_arg, &sym_value, 8);
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}
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#endif
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else if (r_type == R_ALPHA_DTPMOD64)
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{
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# ifdef RTLD_BOOTSTRAP
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|
/* During startup the dynamic linker is always index 1. */
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|
*reloc_addr = 1;
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|
# else
|
|
/* Get the information from the link map returned by the
|
|
resolv function. */
|
|
if (sym_map != NULL)
|
|
*reloc_addr = sym_map->l_tls_modid;
|
|
# endif
|
|
}
|
|
else if (r_type == R_ALPHA_DTPREL64)
|
|
{
|
|
# ifndef RTLD_BOOTSTRAP
|
|
/* During relocation all TLS symbols are defined and used.
|
|
Therefore the offset is already correct. */
|
|
*reloc_addr = sym_raw_value;
|
|
# endif
|
|
}
|
|
else if (r_type == R_ALPHA_TPREL64)
|
|
{
|
|
# ifdef RTLD_BOOTSTRAP
|
|
*reloc_addr = sym_raw_value + map->l_tls_offset;
|
|
# else
|
|
if (sym_map)
|
|
{
|
|
CHECK_STATIC_TLS (map, sym_map);
|
|
*reloc_addr = sym_raw_value + sym_map->l_tls_offset;
|
|
}
|
|
# endif
|
|
}
|
|
else
|
|
_dl_reloc_bad_type (map, r_type, 0);
|
|
}
|
|
}
|
|
|
|
/* Let do-rel.h know that on Alpha if l_addr is 0, all RELATIVE relocs
|
|
can be skipped. */
|
|
#define ELF_MACHINE_REL_RELATIVE 1
|
|
|
|
auto inline void
|
|
__attribute__ ((always_inline))
|
|
elf_machine_rela_relative (Elf64_Addr l_addr, const Elf64_Rela *reloc,
|
|
void *const reloc_addr_arg)
|
|
{
|
|
/* XXX Make some timings. Maybe it's preferable to test for
|
|
unaligned access and only do it the complex way if necessary. */
|
|
Elf64_Addr reloc_addr_val;
|
|
|
|
/* Load value without causing unaligned trap. */
|
|
memcpy (&reloc_addr_val, reloc_addr_arg, 8);
|
|
reloc_addr_val += l_addr;
|
|
|
|
/* Store value without causing unaligned trap. */
|
|
memcpy (reloc_addr_arg, &reloc_addr_val, 8);
|
|
}
|
|
|
|
auto inline void
|
|
__attribute__ ((always_inline))
|
|
elf_machine_lazy_rel (struct link_map *map,
|
|
Elf64_Addr l_addr, const Elf64_Rela *reloc,
|
|
int skip_ifunc)
|
|
{
|
|
Elf64_Addr * const reloc_addr = (void *)(l_addr + reloc->r_offset);
|
|
unsigned long int const r_type = ELF64_R_TYPE (reloc->r_info);
|
|
|
|
if (r_type == R_ALPHA_JMP_SLOT)
|
|
{
|
|
/* Perform a RELATIVE reloc on the .got entry that transfers
|
|
to the .plt. */
|
|
*reloc_addr += l_addr;
|
|
}
|
|
else if (r_type == R_ALPHA_NONE)
|
|
return;
|
|
else
|
|
_dl_reloc_bad_type (map, r_type, 1);
|
|
}
|
|
|
|
#endif /* RESOLVE_MAP */
|