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Diffstat (limited to 'sysdeps/m68k/dl-machine.h')
| -rw-r--r-- | sysdeps/m68k/dl-machine.h | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/sysdeps/m68k/dl-machine.h b/sysdeps/m68k/dl-machine.h new file mode 100644 index 0000000..2208cd2 --- /dev/null +++ b/sysdeps/m68k/dl-machine.h @@ -0,0 +1,230 @@ +/* Machine-dependent ELF dynamic relocation inline functions. m68k version. +Copyright (C) 1996 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#define ELF_MACHINE_NAME "m68k" + +#include <assert.h> +#include <string.h> +#include <link.h> + + +/* Return nonzero iff E_MACHINE is compatible with the running host. */ +static inline int +elf_machine_matches_host (Elf32_Half e_machine) +{ + switch (e_machine) + { + case EM_68K: + return 1; + default: + return 0; + } +} + + +/* Return the run-time address of the _GLOBAL_OFFSET_TABLE_. + Must be inlined in a function which uses global data. */ +static inline Elf32_Addr * +elf_machine_got (void) +{ + register Elf32_Addr *got asm ("%a5"); + return got; +} + + +/* Return the run-time load address of the shared object. */ +static inline Elf32_Addr +elf_machine_load_address (void) +{ + ... +} + +/* Perform the relocation specified by RELOC and SYM (which is fully resolved). + MAP is the object containing the reloc. */ + +static inline void +elf_machine_rela (struct link_map *map, + const Elf32_Rela *reloc, + Elf32_Addr sym_loadaddr, const Elf32_Sym *sym) +{ + Elf32_Addr *const reloc_addr = (void *) (map->l_addr + reloc->r_offset); + const Elf32_Addr sym_value = sym ? sym_loadaddr + sym->st_value : 0; + + switch (ELF32_R_TYPE (reloc->r_info)) + { + case R_68K_COPY: + memcpy (reloc_addr, (void *) sym_value, sym->st_size); + break; + case R_68K_GLOB_DAT: + case R_68K_JMP_SLOT: + *reloc_addr = sym_value; + break; + case R_68K_8: + *(char *) reloc_addr = sym_value + reloc->r_addend; + break; + case R_68K_16: + *(short *) reloc_addr = sym_value + reloc->r_addend; + break; + case R_68K_32: + *reloc_addr = sym_value + reloc->r_addend; + break; + case R_68K_RELATIVE: + *reloc_addr = map->l_addr + reloc->r_addend; + break; + case R_68K_PC8: + *(char *) reloc_addr = (sym_value + reloc->r_addend + - (Elf32_Addr) reloc_addr); + break; + case R_68K_PC16: + *(short *) reloc_addr = (sym_value + reloc->r_addend + - (Elf32_Addr) reloc_addr); + break; + case R_68K_PC32: + *reloc_addr = sym_value + reloc->r_addend - (Elf32_Addr) reloc_addr; + break; + case R_68K_NONE: /* Alright, Wilbur. */ + break; + default: + assert (! "unexpected dynamic reloc type"); + break; + } +} + +static inline void +elf_machine_lazy_rel (struct link_map *map, const Elf32_Rela *reloc) +{ + Elf32_Addr *const reloc_addr = (void *) (map->l_addr + reloc->r_offset); + switch (ELF32_R_TYPE (reloc->r_info)) + { + case R_68K_NONE: + break; + case R_68K_JMP_SLOT: + *reloc_addr += map->l_addr; + break; + default: + assert (! "unexpected PLT reloc type"); + break; + } +} + +/* The m68k never uses Elf32_Rel relocations. */ +#define ELF_MACHINE_NO_REL 1 + + +/* Set up the loaded object described by L so its unrelocated PLT + entries will jump to the on-demand fixup code in dl-runtime.c. */ + +static inline void +elf_machine_runtime_setup (struct link_map *l, int lazy) +{ + Elf32_Addr *got; + extern void _dl_runtime_resolve (Elf32_Word); + + if (l->l_info[DT_JMPREL] && lazy) + { + /* The GOT entries for functions in the PLT have not yet been + filled in. Their initial contents will arrange when called + to push an offset into the .rela.plt section, push + _GLOBAL_OFFSET_TABLE_[1], and then jump to + _GLOBAL_OFFSET_TABLE_[2]. */ + got = (Elf32_Addr *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr); + got[1] = (Elf32_Addr) l; /* Identify this shared object. */ + /* This function will get called to fix up the GOT entry + indicated by the offset on the stack, and then jump to the + resolved address. */ + got[2] = (Elf32_Addr) &_dl_runtime_resolve; + } + + /* This code is used in dl-runtime.c to call the `fixup' function + and then redirect to the address it returns. */ +#define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\ +| Trampoline for _dl_runtime_resolver + .globl _dl_runtime_resolve + .type _dl_runtime_resolve, @function +_dl_runtime_resolve: + | Save %a0 (struct return address). + move.l %a0, -(%sp) + | Call the real address resolver. + bsr.l fixup + | Restore register %a0. + move.l (%sp)+, %a0 + | Pop parameters + addq.l #8, %sp + | Call real function. + jmp (%d0) + .size _dl_runtime_resolve, . - _dl_runtime_resolve +"); +#define ELF_MACHINE_RUNTIME_FIXUP_ARGS long int save_a0 +} + + +/* Mask identifying addresses reserved for the user program, + where the dynamic linker should not map anything. */ +#define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL + +/* Initial entry point code for the dynamic linker. + The C function `_dl_start' is the real entry point; + its return value is the user program's entry point. */ + +#define RTLD_START asm ("\ +.text +.globl _start +.globl _dl_start_user +_start: + jbsr _dl_start +_dl_start_user: + | Save the user entry point address in %a4. + move.l %d0, %a4 + | Point %a5 at the GOT. + lea _GLOBAL_OFFSET_TABLE_@GOTPC(%pc), %a5 + | See if we were run as a command with the executable file + | name as an extra leading argument. + move.l ([_dl_skip_args@GOT, %a5]), %d0 + jeq 0f + | Pop the original argument count + move.l (%sp)+, %d1 + | Subtract _dl_skip_args from it. + sub.l %d0, %d1 + | Adjust the stack pointer to skip _dl_skip_args words. + lea (%sp, %d0*4), %sp + | Push back the modified argument count. + move.l %d1, -(%sp) + | Call _dl_init_next to return the address of an initializer + | function to run. +0: bsr.l _dl_init_next@PLTPC + | Check for zero return, when out of initializers. + tst.l %d0 + jeq 1f + | Call the shared object initializer function. + | NOTE: We depend only on the registers (%a4 and %a5) + | and the return address pushed by this call; + | the initializer is called with the stack just + | as it appears on entry, and it is free to move + | the stack around, as long as it winds up jumping to + | the return address on the top of the stack. + move.l %d0, %a0 + jsr (%a0) + | Loop to call _dl_init_next for the next initializer. + jra 0b +1: | Pass our finalizer function to the user in %a1. + move.l _dl_fini@GOT(%a5), %a1 + | Initialize %fp with the stack pointer. + move.l %sp, %fp + | Jump to the user's entry point. + jmp (%a4)"); |