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Diffstat (limited to 'sysdeps/mips/mips64/dl-machine.h')
| -rw-r--r-- | sysdeps/mips/mips64/dl-machine.h | 594 |
1 files changed, 594 insertions, 0 deletions
diff --git a/sysdeps/mips/mips64/dl-machine.h b/sysdeps/mips/mips64/dl-machine.h new file mode 100644 index 0000000000..3277b109d9 --- /dev/null +++ b/sysdeps/mips/mips64/dl-machine.h @@ -0,0 +1,594 @@ +/* Machine-dependent ELF dynamic relocation inline functions. MIPS version. + Copyright (C) 1996, 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Kazumoto Kojima <kkojima@info.kanagawa-u.ac.jp>. + + 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., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#ifndef dl_machine_h +#define dl_machine_h + +#define ELF_MACHINE_NAME "MIPS" + +#include <assert.h> +#include <entry.h> + +#ifndef ENTRY_POINT +#error ENTRY_POINT needs to be defined for MIPS. +#endif + +#ifndef _RTLD_PROLOGUE +#ifdef __STDC__ +#define _RTLD_PROLOGUE(entry) "\n\t.globl " #entry \ + "\n\t.ent " #entry \ + "\n\t" #entry ":\n\t" +#else +#define _RTLD_PROLOGUE(entry) "\n\t.globl entry\n\t.ent entry\n\t entry:\n\t" +#endif +#endif + +#ifndef _RTLD_EPILOGUE +#ifdef __STDC__ +#define _RTLD_EPILOGUE(entry) "\t.end " #entry "\n" +#else +#define _RTLD_EPILOGUE(entry) "\t.end entry\n" +#endif +#endif + +/* I have no idea what I am doing. */ +#define ELF_MACHINE_RELOC_NOPLT -1 +#define elf_machine_lookup_noplt_p(type) (1) +#define elf_machine_lookup_noexec_p(type) (0) + +/* Translate a processor specific dynamic tag to the index + in l_info array. */ +#define DT_MIPS(x) (DT_MIPS_##x - DT_LOPROC + DT_NUM) + +#if 0 +/* We may need 64k alignment. */ +#define ELF_MACHINE_ALIGN_MASK 0xffff +#endif + +/* + * MIPS libraries are usually linked to a non-zero base address. We + * subtrace the base address from the address where we map the object + * to. This results in more efficient address space usage. + */ +#if 0 +#define MAP_BASE_ADDR(l) ((l)->l_info[DT_MIPS(BASE_ADDRESS)] ? \ + (l)->l_info[DT_MIPS(BASE_ADDRESS)]->d_un.d_ptr : 0) +#else +#define MAP_BASE_ADDR(l) 0x5ffe0000 +#endif + +/* If there is a DT_MIPS_RLD_MAP entry in the dynamic section, fill it in + with the run-time address of the r_debug structure */ +#define ELF_MACHINE_DEBUG_SETUP(l,r) \ +do { if ((l)->l_info[DT_MIPS (RLD_MAP)]) \ + *(ElfW(Addr) *)((l)->l_info[DT_MIPS (RLD_MAP)]->d_un.d_ptr) = \ + (ElfW(Addr)) (r); \ + } while (0) + +/* Return nonzero iff E_MACHINE is compatible with the running host. */ +static inline int __attribute__ ((unused)) +elf_machine_matches_host (ElfW(Half) e_machine) +{ + switch (e_machine) + { + case EM_MIPS: + case EM_MIPS_RS4_BE: + return 1; + default: + return 0; + } +} + +/* Return the link-time address of _DYNAMIC. Conveniently, this is the ++ first element of the GOT. This must be inlined in a function which ++ uses global data. */ ++static inline ElfW(Addr) ++elf_machine_dynamic (void) ++{ ++ register ElfW(Addr) gp asm ("$28"); ++ return * (ElfW(Addr) *) (gp - 0x7ff0); ++} ++ +static inline ElfW(Addr) * +elf_mips_got_from_gpreg (ElfW(Addr) gpreg) +{ + /* FIXME: the offset of gp from GOT may be system-dependent. */ + return (ElfW(Addr) *) (gpreg - 0x7ff0); +} + +/* Return the run-time address of the _GLOBAL_OFFSET_TABLE_. + Must be inlined in a function which uses global data. */ +static inline ElfW(Addr) * +elf_machine_got (void) +{ + ElfW(Addr) gp; + + __asm__ __volatile__("move %0, $28\n\t" : "=r" (gp)); + return elf_mips_got_from_gpreg (gp); +} + + +/* Return the run-time load address of the shared object. */ +static inline ElfW(Addr) +elf_machine_load_address (void) +{ + ElfW(Addr) addr; + asm (" .set noreorder\n" + " dla %0, here\n" + " bltzal $0, here\n" + " nop\n" + "here: dsubu %0, $31, %0\n" + " .set reorder\n" + : "=r" (addr) + : /* No inputs */ + : "$31"); + return addr; +} + +/* The MSB of got[1] of a gnu object is set to identify gnu objects. */ +#define ELF_MIPS_GNU_GOT1_MASK 0x80000000 + +/* Relocate GOT. */ +static inline void +elf_machine_got_rel (struct link_map *map, int lazy) +{ + ElfW(Addr) *got; + ElfW(Sym) *sym; + int i, n; + struct link_map **scope; + const char *strtab + = ((void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr); + +#define RESOLVE_GOTSYM(sym) \ + ({ \ + const ElfW(Sym) *ref = sym; \ + ElfW(Addr) sym_loadaddr; \ + sym_loadaddr = _dl_lookup_symbol (strtab + sym->st_name, &ref, scope, \ + map->l_name, ELF_MACHINE_RELOC_NOPLT);\ + (ref)? sym_loadaddr + ref->st_value: 0; \ + }) + + got = (ElfW(Addr) *) ((void *) map->l_addr + + map->l_info[DT_PLTGOT]->d_un.d_ptr); + + /* got[0] is reserved. got[1] is also reserved for the dynamic object + generated by gnu ld. Skip these reserved entries from relocation. */ + i = (got[1] & ELF_MIPS_GNU_GOT1_MASK)? 2: 1; + n = map->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val; + /* Add the run-time display to all local got entries. */ + while (i < n) + got[i++] += map->l_addr; + + /* Set scope. */ + scope = _dl_object_relocation_scope (map); + + /* Handle global got entries. */ + got += n; + sym = (ElfW(Sym) *) ((void *) map->l_addr + + map->l_info[DT_SYMTAB]->d_un.d_ptr); + sym += map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val; + i = (map->l_info[DT_MIPS (SYMTABNO)]->d_un.d_val + - map->l_info[DT_MIPS (GOTSYM)]->d_un.d_val); + + while (i--) + { + if (sym->st_shndx == SHN_UNDEF) + { + if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC) + { + if (sym->st_value && lazy) + *got = sym->st_value + map->l_addr; + else + *got = RESOLVE_GOTSYM (sym); + } + else /* if (*got == 0 || *got == QS) */ + *got = RESOLVE_GOTSYM (sym); + } + else if (sym->st_shndx == SHN_COMMON) + *got = RESOLVE_GOTSYM (sym); + else if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC + && *got != sym->st_value + && lazy) + *got += map->l_addr; + else if (ELFW(ST_TYPE) (sym->st_info) == STT_SECTION) + { + if (sym->st_other == 0) + *got += map->l_addr; + } + else + *got = RESOLVE_GOTSYM (sym); + + got++; + sym++; + } + +#undef RESOLVE_GOTSYM + *_dl_global_scope_end = NULL; + + return; +} + +/* Set up the loaded object described by L so its stub function + will jump to the on-demand fixup code in dl-runtime.c. */ + +static inline int +elf_machine_runtime_setup (struct link_map *l, int lazy) +{ + ElfW(Addr) *got; + extern void _dl_runtime_resolve (ElfW(Word)); + extern int _dl_mips_gnu_objects; + +#ifdef RTLD_BOOTSTRAP + { + return lazy; + } +#endif + if (lazy) + { + /* The GOT entries for functions have not yet been filled in. + Their initial contents will arrange when called to put an + offset into the .dynsym section in t8, the return address + in t7 and then jump to _GLOBAL_OFFSET_TABLE[0]. */ + got = (ElfW(Addr) *) ((void *) l->l_addr + + l->l_info[DT_PLTGOT]->d_un.d_ptr); + + /* This function will get called to fix up the GOT entry indicated by + the register t8, and then jump to the resolved address. */ + got[0] = (ElfW(Addr)) &_dl_runtime_resolve; + + /* Store l to _GLOBAL_OFFSET_TABLE[1] for gnu object. The MSB + of got[1] of a gnu object is set to identify gnu objects. + Where we can store l for non gnu objects? XXX */ + if ((got[1] & ELF_MIPS_GNU_GOT1_MASK) != 0) + got[1] = (ElfW(Addr)) ((unsigned) l | ELF_MIPS_GNU_GOT1_MASK); + else + _dl_mips_gnu_objects = 0; + } + + /* Relocate global offset table. */ + elf_machine_got_rel (l, lazy); + + return lazy; +} + +/* Get link_map for this object. */ +static inline struct link_map * +elf_machine_runtime_link_map (ElfW(Addr) gpreg, ElfW(Addr) stub_pc) +{ + extern int _dl_mips_gnu_objects; + + /* got[1] is reserved to keep its link map address for the shared + object generated by gnu linker. If all are such object, we can + find link map from current GPREG simply. If not so, get link map + for callers object containing STUB_PC. */ + + if (_dl_mips_gnu_objects) + { + ElfW(Addr) *got = elf_mips_got_from_gpreg (gpreg); + ElfW(Word) g1; + + g1 = ((ElfW(Word) *) got)[1]; + + if ((g1 & ELF_MIPS_GNU_GOT1_MASK) != 0) + return (struct link_map *) (g1 & ~ELF_MIPS_GNU_GOT1_MASK); + } + + { + struct link_map *l = _dl_loaded; + struct link_map *ret = 0; + ElfW(Addr) candidate = 0; + + while (l) + { + ElfW(Addr) base = 0; + const ElfW(Phdr) *p = l->l_phdr; + ElfW(Half) this, nent = l->l_phnum; + + /* Get the base. */ + for (this = 0; this < nent; this++) + if (p[this].p_type == PT_LOAD) + { + base = p[this].p_vaddr + l->l_addr; + break; + } + if (! base) + { + l = l->l_next; + continue; + } + + /* Find closest link base addr. */ + if ((base < stub_pc) && (candidate < base)) + { + candidate = base; + ret = l; + } + l = l->l_next; + } + if (candidate && ret && (candidate < stub_pc)) + return ret; + else if (!candidate) + return _dl_loaded; + } + + _dl_signal_error (0, NULL, "cannot find runtime link map"); + return NULL; +} + +/* Mips has no PLT but define elf_machine_relplt to be elf_machine_rel. */ +#define elf_machine_relplt elf_machine_rel + +/* Define mips specific runtime resolver. The function __dl_runtime_resolve + is called from assembler function _dl_runtime_resolve which converts + special argument registers t7 ($15) and t8 ($24): + t7 address to return to the caller of the function + t8 index for this function symbol in .dynsym + to usual c arguments. */ + +#define ELF_MACHINE_RUNTIME_TRAMPOLINE \ +/* The flag _dl_mips_gnu_objects is set if all dynamic objects are \ + generated by the gnu linker. */ \ +int _dl_mips_gnu_objects = 1; \ + \ +/* This is called from assembly stubs below which the compiler can't see. */ \ +static ElfW(Addr) \ +__dl_runtime_resolve (ElfW(Word), ElfW(Word), ElfW(Addr), ElfW(Addr)) \ + __attribute__ ((unused)); \ + \ +static ElfW(Addr) \ +__dl_runtime_resolve (ElfW(Word) sym_index, \ + ElfW(Word) return_address, \ + ElfW(Addr) old_gpreg, \ + ElfW(Addr) stub_pc) \ +{ \ + struct link_map *l = elf_machine_runtime_link_map (old_gpreg, stub_pc); \ + const ElfW(Sym) *const symtab \ + = (const ElfW(Sym) *) (l->l_addr + l->l_info[DT_SYMTAB]->d_un.d_ptr); \ + const char *strtab \ + = (void *) (l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr); \ + const ElfW(Addr) *got \ + = (const ElfW(Addr) *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr); \ + const ElfW(Word) local_gotno \ + = (const ElfW(Word)) l->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val; \ + const ElfW(Word) gotsym \ + = (const ElfW(Word)) l->l_info[DT_MIPS (GOTSYM)]->d_un.d_val; \ + const ElfW(Sym) *definer; \ + ElfW(Addr) loadbase; \ + ElfW(Addr) funcaddr; \ + struct link_map **scope; \ + \ + /* Look up the symbol's run-time value. */ \ + scope = _dl_object_relocation_scope (l); \ + definer = &symtab[sym_index]; \ + \ + loadbase = _dl_lookup_symbol (strtab + definer->st_name, &definer, \ + scope, l->l_name, ELF_MACHINE_RELOC_NOPLT); \ + \ + *_dl_global_scope_end = NULL; \ + \ + /* Apply the relocation with that value. */ \ + funcaddr = loadbase + definer->st_value; \ + *(got + local_gotno + sym_index - gotsym) = funcaddr; \ + \ + return funcaddr; \ +} \ + \ +asm ("\n \ + .text\n \ + .align 3\n \ + .globl _dl_runtime_resolve\n \ + .type _dl_runtime_resolve,@function\n \ + .ent _dl_runtime_resolve\n \ +_dl_runtime_resolve:\n \ + .set noreorder\n \ + # Save old GP to $3.\n \ + move $3,$28\n \ + # Modify t9 ($25) so as to point .cpload instruction.\n \ + daddu $25,2*8\n \ + # Compute GP.\n \ + .cpload $25\n \ + .set reorder\n \ + # Save slot call pc.\n \ + move $2, $31\n \ + # Save arguments and sp value in stack.\n \ + dsubu $29, 10*8\n \ + .cprestore 8*8\n \ + sd $15, 9*8($29)\n \ + sd $4, 3*8($29)\n \ + sd $5, 4*8($29)\n \ + sd $6, 5*8($29)\n \ + sd $7, 6*8($29)\n \ + sd $16, 7*8($29)\n \ + move $16, $29\n \ + move $4, $24\n \ + move $5, $15\n \ + move $6, $3\n \ + move $7, $2\n \ + jal __dl_runtime_resolve\n \ + move $29, $16\n \ + ld $31, 9*8($29)\n \ + ld $4, 3*8($29)\n \ + ld $5, 4*8($29)\n \ + ld $6, 5*8($29)\n \ + ld $7, 6*8($29)\n \ + ld $16, 7*8($29)\n \ + daddu $29, 10*8\n \ + move $25, $2\n \ + jr $25\n \ + .end _dl_runtime_resolve\n \ +"); + +/* 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. + Note how we have to be careful about two things: + + 1) That we allocate a minimal stack of 24 bytes for + every function call, the MIPS ABI states that even + if all arguments are passed in registers the procedure + called can use the 16 byte area pointed to by $sp + when it is called to store away the arguments passed + to it. + + 2) That under Linux the entry is named __start + and not just plain _start. */ + +#define RTLD_START asm ("\ + .text\n\ + .align 3\n"\ +_RTLD_PROLOGUE (ENTRY_POINT)\ +" .globl _dl_start_user\n\ + .set noreorder\n\ + bltzal $0, 0f\n\ + nop\n\ +0: .cpload $31\n\ + .set reorder\n\ + # i386 ABI book says that the first entry of GOT holds\n\ + # the address of the dynamic structure. Though MIPS ABI\n\ + # doesn't say nothing about this, I emulate this here.\n\ + dla $4, _DYNAMIC\n\ + sd $4, -0x7ff0($28)\n\ + move $4, $29\n\ + jal _dl_start\n\ + # Get the value of label '_dl_start_user' in t9 ($25).\n\ + dla $25, _dl_start_user\n\ +_dl_start_user:\n\ + .set noreorder\n\ + .cpload $25\n\ + .set reorder\n\ + move $16, $28\n\ + # Save the user entry point address in saved register.\n\ + move $17, $2\n\ + # See if we were run as a command with the executable file\n\ + # name as an extra leading argument.\n\ + ld $2, _dl_skip_args\n\ + beq $2, $0, 1f\n\ + # Load the original argument count.\n\ + ld $4, 0($29)\n\ + # Subtract _dl_skip_args from it.\n\ + dsubu $4, $2\n\ + # Adjust the stack pointer to skip _dl_skip_args words.\n\ + dsll $2,2\n\ + daddu $29, $2\n\ + # Save back the modified argument count.\n\ + sd $4, 0($29)\n\ + # Get _dl_default_scope[2] as argument in _dl_init_next call below.\n\ +1: dla $2, _dl_default_scope\n\ + ld $4, 2*8($2)\n\ + # Call _dl_init_next to return the address of an initializer\n\ + # function to run.\n\ + jal _dl_init_next\n\ + move $28, $16\n\ + # Check for zero return, when out of initializers.\n\ + beq $2, $0, 2f\n\ + # Call the shared object initializer function.\n\ + move $25, $2\n\ + ld $4, 0($29)\n\ + ld $5, 1*8($29)\n\ + ld $6, 2*8($29)\n\ + ld $7, 3*8($29)\n\ + jalr $25\n\ + move $28, $16\n\ + # Loop to call _dl_init_next for the next initializer.\n\ + b 1b\n\ + # Pass our finalizer function to the user in ra.\n\ +2: dla $31, _dl_fini\n\ + # Jump to the user entry point.\n\ + move $25, $17\n\ + ld $4, 0($29)\n\ + ld $5, 1*8($29)\n\ + ld $6, 2*8$29)\n\ + ld $7, 3*8($29)\n\ + jr $25\n"\ +_RTLD_EPILOGUE(ENTRY_POINT) \ +); + + +/* The MIPS never uses Elfxx_Rela relocations. */ +#define ELF_MACHINE_NO_RELA 1 + +#endif /* !dl_machine_h */ + +#ifdef RESOLVE + +/* Perform the relocation specified by RELOC and SYM (which is fully resolved). + MAP is the object containing the reloc. */ + +static inline void +elf_machine_rel (struct link_map *map, const ElfW(Rel) *reloc, + const ElfW(Sym) *sym, const struct r_found_version *version) +{ + ElfW(Addr) *const reloc_addr = (void *) (map->l_addr + reloc->r_offset); + ElfW(Addr) loadbase; + ElfW(Addr) undo __attribute__ ((unused)); + + switch (ELFW(R_TYPE) (reloc->r_info)) + { + case R_MIPS_REL32: + { + ElfW(Addr) undo = 0; + + if (ELFW(ST_BIND) (sym->st_info) == STB_LOCAL + && (ELFW(ST_TYPE) (sym->st_info) == STT_SECTION + || ELFW(ST_TYPE) (sym->st_info) == STT_NOTYPE)) + { + *reloc_addr += map->l_addr; + break; + } +#ifndef RTLD_BOOTSTRAP + /* This is defined in rtld.c, but nowhere in the static libc.a; + make the reference weak so static programs can still link. This + declaration cannot be done when compiling rtld.c (i.e. #ifdef + RTLD_BOOTSTRAP) because rtld.c contains the common defn for + _dl_rtld_map, which is incompatible with a weak decl in the same + file. */ + weak_extern (_dl_rtld_map); + if (map == &_dl_rtld_map) + /* Undo the relocation done here during bootstrapping. Now we will + relocate it anew, possibly using a binding found in the user + program or a loaded library rather than the dynamic linker's + built-in definitions used while loading those libraries. */ + undo = map->l_addr + sym->st_value; +#endif + loadbase = RESOLVE (&sym, version, 0); + *reloc_addr += (sym ? (loadbase + sym->st_value) : 0) - undo; + } + break; + case R_MIPS_NONE: /* Alright, Wilbur. */ + break; + default: + assert (! "unexpected dynamic reloc type"); + break; + } +} + +static inline void +elf_machine_lazy_rel (struct link_map *map, const ElfW(Rel) *reloc) +{ + /* Do nothing. */ +} + +#endif /* RESOLVE */ |