308 lines
9.5 KiB
C
308 lines
9.5 KiB
C
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/* Machine-dependent ELF dynamic relocation inline functions. Nios II version.
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Copyright (C) 1995-2022 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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#ifndef dl_machine_h
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#define dl_machine_h
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#define ELF_MACHINE_NAME "nios2"
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#include <string.h>
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#include <link.h>
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#include <dl-tls.h>
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#include <dl-static-tls.h>
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#include <dl-machine-rel.h>
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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 Elf32_Ehdr *ehdr)
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{
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return ehdr->e_machine == EM_ALTERA_NIOS2;
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}
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/* Return the link-time address of _DYNAMIC. Conveniently, this is the
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first element of the GOT. */
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static inline Elf32_Addr
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elf_machine_dynamic (void)
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{
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Elf32_Addr *dynamic;
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int tmp;
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asm ("nextpc\t%0\n\t"
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"1: movhi\t%1, %%hiadj(_GLOBAL_OFFSET_TABLE_ - 1b)\n\t"
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"addi\t%1, %1, %%lo(_GLOBAL_OFFSET_TABLE_ - 1b)\n\t"
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"add\t%0, %0, %1\n"
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: "=r" (dynamic), "=r" (tmp));
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return *dynamic;
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}
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/* Return the run-time load address of the shared object. */
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static inline Elf32_Addr
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elf_machine_load_address (void)
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{
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Elf32_Addr result;
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int tmp;
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asm ("nextpc\t%0\n\t"
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"1: movhi\t%1, %%hiadj(1b)\n\t"
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"addi\t%1, %1, %%lo(1b)\n\t"
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"sub\t%0, %0, %1\n"
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: "=r" (result), "=r" (tmp));
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return result;
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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 __attribute__ ((always_inline))
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elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
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int lazy, int profile)
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{
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extern void _dl_runtime_resolve (Elf32_Word);
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if (l->l_info[DT_JMPREL] && lazy)
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{
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/* The GOT entries for functions in the PLT have not yet been filled
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in. Their initial contents will arrange when called to load r15 with
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an offset into the .got section, load r14 with
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_GLOBAL_OFFSET_TABLE_[1], and then jump to _GLOBAL_OFFSET_TABLE[2].
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*/
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Elf32_Addr *got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
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got[1] = (Elf32_Addr) l; /* Identify this shared object. */
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/* This function will get called to fix up the GOT entry indicated by
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the offset on the stack, and then jump to the resolved address. */
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got[2] = (Elf32_Addr) &_dl_runtime_resolve;
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}
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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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.text\n\
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.globl _start\n\
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.type _start, %function\n\
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_start:\n\
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/* At start time, all the args are on the stack. */\n\
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mov r4, sp\n\
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\n\
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/* Start the calculation of the GOT pointer. */\n\
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nextpc r22\n\
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1: movhi r8, %hiadj(_gp_got - 1b)\n\
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addi r8, r8, %lo(_gp_got - 1b)\n\
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\n\
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/* Figure out where _dl_start will need to return to. */\n\
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movhi ra, %hiadj(2f - 1b)\n\
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addi ra, ra, %lo(2f - 1b)\n\
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add ra, ra, r22\n\
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\n\
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/* Finish the calculation of the GOT pointer. */\n\
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add r22, r22, r8\n\
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\n\
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br _dl_start\n\
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\n\
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/* Save the returned user entry point. */\n\
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2: mov r16, r2\n\
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\n\
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/* Initialize gp. */\n\
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ldw r4, %got(_rtld_local)(r22)\n\
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ldw r4, 0(r4)\n\
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ldw r8, %call(_dl_nios2_get_gp_value)(r22)\n\
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callr r8\n\
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mov gp, r2\n\
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\n\
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/* Find the main_map from the GOT. */\n\
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ldw r4, %got(_rtld_local)(r22)\n\
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ldw r4, 0(r4)\n\
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\n\
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/* Load adjusted argc. */\n\
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ldw r2, %got(_dl_argc)(r22)\n\
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ldw r5, 0(r2)\n\
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\n\
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/* Load adjsuted argv. */\n\
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ldw r2, %got(_dl_argv)(r22)\n\
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ldw r6, 0(r2)\n\
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\n\
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/* envp = argv + argc + 1 */\n\
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addi r7, r5, 1\n\
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slli r7, r7, 2\n\
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add r7, r7, r6\n\
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\n\
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/* Call _dl_init through the PLT. */\n\
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ldw r8, %call(_dl_init)(r22)\n\
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callr r8\n\
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\n\
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/* Find the finalization function. */\n\
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ldw r4, %got(_dl_fini)(r22)\n\
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\n\
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/* Jump to the user's entry point. */\n\
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jmp r16\n\
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");
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/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
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PLT entries should not be allowed to define the value.
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ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
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of the main executable's symbols, as for a COPY reloc. */
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#define elf_machine_type_class(type) \
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((((type) == R_NIOS2_JUMP_SLOT \
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|| (type) == R_NIOS2_TLS_DTPMOD \
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|| (type) == R_NIOS2_TLS_DTPREL \
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|| (type) == R_NIOS2_TLS_TPREL) * 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_NIOS2_JUMP_SLOT
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/* Fixup a PLT entry to bounce directly to the function at VALUE. */
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static inline Elf32_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 Elf32_Rela *reloc,
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Elf32_Addr *reloc_addr, Elf32_Addr value)
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{
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return *reloc_addr = value;
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}
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/* Return the final value of a plt relocation. */
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static inline Elf32_Addr
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elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
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Elf32_Addr value)
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{
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return value;
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}
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/* Names of the architecture-specific auditing callback functions. */
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#define ARCH_LA_PLTENTER nios2_gnu_pltenter
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#define ARCH_LA_PLTEXIT nios2_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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LOADADDR is the load address of the object; INFO is an array indexed
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by DT_* of the .dynamic section info. */
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static inline void __attribute__ ((always_inline))
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elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
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const ElfW(Rela) *reloc, const ElfW(Sym) *sym,
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const struct r_found_version *version,
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void *const reloc_addr_arg, int skip_ifunc)
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{
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Elf32_Addr *const reloc_addr = reloc_addr_arg;
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const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
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if (__glibc_unlikely (r_type == R_NIOS2_RELATIVE))
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*reloc_addr = map->l_addr + reloc->r_addend;
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else if (__glibc_unlikely (r_type == R_NIOS2_NONE))
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return;
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else
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{
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const Elf32_Sym *const refsym = sym;
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struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
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r_type);
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Elf32_Addr value = SYMBOL_ADDRESS (sym_map, sym, true);
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switch (r_type)
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{
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case R_NIOS2_COPY:
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if (sym == NULL)
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/* This can happen in trace mode if an object could not be
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found. */
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break;
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if (sym->st_size > refsym->st_size
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|| (sym->st_size < refsym->st_size && GLRO(dl_verbose)))
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{
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const char *strtab;
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strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
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_dl_error_printf ("\
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%s: Symbol `%s' has different size in shared object, consider re-linking\n",
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rtld_progname ?: "<program name unknown>",
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strtab + refsym->st_name);
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}
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memcpy (reloc_addr_arg, (void *) value,
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MIN (sym->st_size, refsym->st_size));
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break;
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case R_NIOS2_GLOB_DAT:
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case R_NIOS2_JUMP_SLOT:
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# ifdef RTLD_BOOTSTRAP
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/* Fix weak undefined references. */
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if (sym != NULL && sym->st_value == 0)
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*reloc_addr = 0;
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else
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# endif
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*reloc_addr = value;
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break;
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#ifndef RTLD_BOOTSTRAP
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case R_NIOS2_TLS_DTPMOD:
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/* Get the information from the link map returned by the
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resolv function. */
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if (sym_map != NULL)
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*reloc_addr = sym_map->l_tls_modid;
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break;
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case R_NIOS2_TLS_DTPREL:
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*reloc_addr = reloc->r_addend + TLS_DTPREL_VALUE(sym);
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break;
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case R_NIOS2_TLS_TPREL:
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if (sym != NULL)
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{
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CHECK_STATIC_TLS (map, sym_map);
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*reloc_addr = reloc->r_addend + TLS_TPREL_VALUE(sym_map, sym);
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}
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break;
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#endif
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case R_NIOS2_BFD_RELOC_32:
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*reloc_addr = value + reloc->r_addend;
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break;
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default:
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_dl_reloc_bad_type (map, r_type, 0);
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break;
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}
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}
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}
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static inline void __attribute__((always_inline))
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elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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void *const reloc_addr_arg)
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{
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Elf32_Addr *const reloc_addr = reloc_addr_arg;
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*reloc_addr = l_addr + reloc->r_addend;
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}
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static inline void __attribute__((always_inline))
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elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
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ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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int skip_ifunc)
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{
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Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
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if (ELF32_R_TYPE (reloc->r_info) == R_NIOS2_JUMP_SLOT)
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*reloc_addr += l_addr;
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else
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_dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
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}
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#endif /* RESOLVE_MAP */
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