| /* Machine-dependent ELF dynamic relocation inline functions. i386 version. |
| Copyright (C) 1995,96,97,98,99,2000,2001 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 Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; 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 "i386" |
| |
| #include <sys/param.h> |
| #include <machine/weakalias.h> |
| |
| /* Return nonzero iff ELF header is compatible with the running host. */ |
| static inline int __attribute__ ((unused)) |
| elf_machine_matches_host (const Elf32_Ehdr *ehdr) |
| { |
| return ehdr->e_machine == EM_386; |
| } |
| |
| |
| /* 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 Elf32_Addr __attribute__ ((unused)) |
| elf_machine_dynamic (void) |
| { |
| register Elf32_Addr *got asm ("%ebx"); |
| return *got; |
| } |
| |
| |
| /* Return the run-time load address of the shared object. */ |
| static inline Elf32_Addr __attribute__ ((unused)) |
| elf_machine_load_address (void) |
| { |
| Elf32_Addr addr; |
| asm ("leal _dl_start@GOTOFF(%%ebx), %0\n" |
| "subl _dl_start@GOT(%%ebx), %0" |
| : "=r" (addr) : : "cc"); |
| return addr; |
| } |
| |
| #if !defined PROF && !__BOUNDED_POINTERS__ |
| /* We add a declaration of this function here so that in dl-runtime.c |
| the ELF_MACHINE_RUNTIME_TRAMPOLINE macro really can pass the parameters |
| in registers. |
| |
| We cannot use this scheme for profiling because the _mcount call |
| destroys the passed register information. */ |
| /* GKM FIXME: Fix trampoline to pass bounds so we can do |
| without the `__unbounded' qualifier. */ |
| static ElfW(Addr) fixup (struct link_map *__unbounded l, ElfW(Word) reloc_offset) |
| __attribute__ ((regparm (2), unused)); |
| static ElfW(Addr) profile_fixup (struct link_map *l, ElfW(Word) reloc_offset, |
| ElfW(Addr) retaddr) |
| __attribute__ ((regparm (3), unused)); |
| #endif |
| |
| /* 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 int __attribute__ ((unused)) |
| elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) |
| { |
| Elf32_Addr *got; |
| extern void _dl_runtime_resolve (Elf32_Word); |
| extern void _dl_runtime_profile (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 .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1], |
| and then jump to _GLOBAL_OFFSET_TABLE[2]. */ |
| got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]); |
| got[1] = (Elf32_Addr) l; /* Identify this shared object. */ |
| |
| /* The got[2] entry contains the address of a function which gets |
| called to get the address of a so far unresolved function and |
| jump to it. The profiling extension of the dynamic linker allows |
| to intercept the calls to collect information. In this case we |
| don't store the address in the GOT so that all future calls also |
| end in this function. */ |
| if (__builtin_expect (profile, 0)) |
| { |
| got[2] = (Elf32_Addr) &_dl_runtime_profile; |
| |
| if (_dl_name_match_p (_dl_profile, l)) |
| /* This is the object we are looking for. Say that we really |
| want profiling and the timers are started. */ |
| _dl_profile_map = l; |
| } |
| else |
| /* 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; |
| } |
| |
| return lazy; |
| } |
| |
| /* This code is used in dl-runtime.c to call the `fixup' function |
| and then redirect to the address it returns. */ |
| #if !defined PROF && !__BOUNDED_POINTERS__ |
| # define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\ |
| .text\n\ |
| .globl _dl_runtime_resolve\n\ |
| .type _dl_runtime_resolve, @function\n\ |
| .align 16\n\ |
| _dl_runtime_resolve:\n\ |
| pushl %eax # Preserve registers otherwise clobbered.\n\ |
| pushl %ecx\n\ |
| pushl %edx\n\ |
| movl 16(%esp), %edx # Copy args pushed by PLT in register. Note\n\ |
| movl 12(%esp), %eax # that `fixup' takes its parameters in regs.\n\ |
| call fixup # Call resolver.\n\ |
| popl %edx # Get register content back.\n\ |
| popl %ecx\n\ |
| xchgl %eax, (%esp) # Get %eax contents end store function address.\n\ |
| ret $8 # Jump to function address.\n\ |
| .size _dl_runtime_resolve, .-_dl_runtime_resolve\n\ |
| \n\ |
| .globl _dl_runtime_profile\n\ |
| .type _dl_runtime_profile, @function\n\ |
| .align 16\n\ |
| _dl_runtime_profile:\n\ |
| pushl %eax # Preserve registers otherwise clobbered.\n\ |
| pushl %ecx\n\ |
| pushl %edx\n\ |
| movl 20(%esp), %ecx # Load return address\n\ |
| movl 16(%esp), %edx # Copy args pushed by PLT in register. Note\n\ |
| movl 12(%esp), %eax # that `fixup' takes its parameters in regs.\n\ |
| call profile_fixup # Call resolver.\n\ |
| popl %edx # Get register content back.\n\ |
| popl %ecx\n\ |
| xchgl %eax, (%esp) # Get %eax contents end store function address.\n\ |
| ret $8 # Jump to function address.\n\ |
| .size _dl_runtime_profile, .-_dl_runtime_profile\n\ |
| .previous\n\ |
| "); |
| #else |
| # define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\n\ |
| .text\n\ |
| .globl _dl_runtime_resolve\n\ |
| .globl _dl_runtime_profile\n\ |
| .type _dl_runtime_resolve, @function\n\ |
| .type _dl_runtime_profile, @function\n\ |
| .align 16\n\ |
| _dl_runtime_resolve:\n\ |
| _dl_runtime_profile:\n\ |
| pushl %eax # Preserve registers otherwise clobbered.\n\ |
| pushl %ecx\n\ |
| pushl %edx\n\ |
| movl 16(%esp), %edx # Push the arguments for `fixup'\n\ |
| movl 12(%esp), %eax\n\ |
| pushl %edx\n\ |
| pushl %eax\n\ |
| call fixup # Call resolver.\n\ |
| popl %edx # Pop the parameters\n\ |
| popl %ecx\n\ |
| popl %edx # Get register content back.\n\ |
| popl %ecx\n\ |
| xchgl %eax, (%esp) # Get %eax contents end store function address.\n\ |
| ret $8 # Jump to function address.\n\ |
| .size _dl_runtime_resolve, .-_dl_runtime_resolve\n\ |
| .size _dl_runtime_profile, .-_dl_runtime_profile\n\ |
| .previous\n\ |
| "); |
| #endif |
| |
| /* Mask identifying addresses reserved for the user program, |
| where the dynamic linker should not map anything. */ |
| #define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL |
| |
| /* 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 ("\n\ |
| .text\n\ |
| .align 16\n\ |
| 0: movl (%esp), %ebx\n\ |
| ret\n\ |
| .align 16\n\ |
| .globl _start\n\ |
| .globl _dl_start_user\n\ |
| _start:\n\ |
| pushl %esp\n\ |
| call _dl_start\n\ |
| popl %ebx\n\ |
| _dl_start_user:\n\ |
| # Save the user entry point address in %edi.\n\ |
| movl %eax, %edi\n\ |
| # Point %ebx at the GOT.\n\ |
| call 0b\n\ |
| addl $_GLOBAL_OFFSET_TABLE_, %ebx\n\ |
| # Store the highest stack address\n\ |
| movl __libc_stack_end@GOT(%ebx), %eax\n\ |
| movl %esp, (%eax)\n\ |
| # See if we were run as a command with the executable file\n\ |
| # name as an extra leading argument.\n\ |
| movl _dl_skip_args@GOT(%ebx), %eax\n\ |
| movl (%eax), %eax\n\ |
| # Pop the original argument count.\n\ |
| popl %edx\n\ |
| # Adjust the stack pointer to skip _dl_skip_args words.\n\ |
| leal (%esp,%eax,4), %esp\n\ |
| # Subtract _dl_skip_args from argc.\n\ |
| subl %eax, %edx\n\ |
| # Push argc back on the stack.\n\ |
| push %edx\n\ |
| # The special initializer gets called with the stack just\n\ |
| # as the application's entry point will see it; it can\n\ |
| # switch stacks if it moves these contents over.\n\ |
| " RTLD_START_SPECIAL_INIT "\n\ |
| # Load the parameters again.\n\ |
| # (eax, edx, ecx, *--esp) = (_dl_loaded, argc, argv, envp)\n\ |
| movl _dl_loaded@GOT(%ebx), %esi\n\ |
| leal 8(%esp,%edx,4), %eax\n\ |
| leal 4(%esp), %ecx\n\ |
| pushl %eax\n\ |
| movl (%esi), %eax\n\ |
| # Call the function to run the initializers.\n\ |
| call _dl_init@PLT\n\ |
| # Pass our finalizer function to the user in %edx, as per ELF ABI.\n\ |
| movl _dl_fini@GOT(%ebx), %edx\n\ |
| # Jump to the user's entry point.\n\ |
| jmp *%edi\n\ |
| .previous\n\ |
| "); |
| |
| #ifndef RTLD_START_SPECIAL_INIT |
| #define RTLD_START_SPECIAL_INIT /* nothing */ |
| #endif |
| |
| /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so |
| PLT entries should not be allowed to define the value. |
| ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one |
| of the main executable's symbols, as for a COPY reloc. */ |
| #define elf_machine_type_class(type) \ |
| ((((type) == R_386_JMP_SLOT) * ELF_RTYPE_CLASS_PLT) \ |
| | (((type) == R_386_COPY) * ELF_RTYPE_CLASS_COPY)) |
| |
| /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */ |
| #define ELF_MACHINE_JMP_SLOT R_386_JMP_SLOT |
| |
| /* The i386 never uses Elf32_Rela relocations. */ |
| #define ELF_MACHINE_NO_RELA 1 |
| |
| /* We define an initialization functions. This is called very early in |
| _dl_sysdep_start. */ |
| #define DL_PLATFORM_INIT dl_platform_init () |
| |
| extern const char *_dl_platform; |
| |
| static inline void __attribute__ ((unused)) |
| dl_platform_init (void) |
| { |
| if (_dl_platform != NULL && *_dl_platform == '\0') |
| /* Avoid an empty string which would disturb us. */ |
| _dl_platform = NULL; |
| } |
| |
| static inline Elf32_Addr |
| elf_machine_fixup_plt (struct link_map *map, lookup_t t, |
| const Elf32_Rel *reloc, |
| Elf32_Addr *reloc_addr, Elf32_Addr value) |
| { |
| return *reloc_addr = value; |
| } |
| |
| /* Return the final value of a plt relocation. */ |
| static inline Elf32_Addr |
| elf_machine_plt_value (struct link_map *map, const Elf32_Rel *reloc, |
| Elf32_Addr value) |
| { |
| return value; |
| } |
| |
| static inline void __attribute__ ((unused)) |
| elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc, |
| const Elf32_Sym *sym, const struct r_found_version *version, |
| Elf32_Addr *const reloc_addr, |
| struct r_scope_elem *scope[]); |
| |
| static inline void __attribute__ ((unused)) |
| elf_machine_rel_relative (Elf32_Addr l_addr, const Elf32_Rel *reloc, |
| Elf32_Addr *const reloc_addr); |
| |
| static inline void |
| elf_machine_lazy_rel (struct link_map *map, |
| Elf32_Addr l_addr, const Elf32_Rel *reloc); |
| |
| #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 __attribute__ ((unused)) |
| elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc, |
| const Elf32_Sym *sym, const struct r_found_version *version, |
| Elf32_Addr *const reloc_addr, |
| struct r_scope_elem *scope[]) |
| { |
| const unsigned int r_type = ELF32_R_TYPE (reloc->r_info); |
| |
| #if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC |
| if (__builtin_expect (r_type == R_386_RELATIVE, 0)) |
| { |
| # if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC |
| /* 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. */ |
| #pragma weak _dl_rtld_map |
| if (map != &_dl_rtld_map) /* Already done in rtld itself. */ |
| # endif |
| *reloc_addr += map->l_addr; |
| } |
| # ifndef RTLD_BOOTSTRAP |
| else if (__builtin_expect (r_type == R_386_NONE, 0)) |
| return; |
| # endif |
| else |
| #endif |
| { |
| #ifndef RTLD_BOOTSTRAP |
| const Elf32_Sym *const refsym = sym; |
| #endif |
| /* String table object symbols. */ |
| const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); |
| Elf32_Addr value = RESOLVE (&sym, version, r_type, scope); |
| if (sym) |
| value += sym->st_value; |
| |
| #ifdef RTLD_BOOTSTRAP |
| assert (r_type == R_386_GLOB_DAT || r_type == R_386_JMP_SLOT); |
| *reloc_addr = value; |
| #else |
| switch (r_type) |
| { |
| case R_386_GLOB_DAT: |
| case R_386_JMP_SLOT: |
| *reloc_addr = value; |
| break; |
| case R_386_32: |
| *reloc_addr += value; |
| break; |
| case R_386_PC32: |
| *reloc_addr += (value - (Elf32_Addr) reloc_addr); |
| break; |
| case R_386_COPY: |
| if (sym == NULL) |
| /* This can happen in trace mode if an object could not be |
| found. */ |
| break; |
| if (__builtin_expect (sym->st_size > refsym->st_size, 0) |
| || (__builtin_expect (sym->st_size < refsym->st_size, 0) |
| && _dl_verbose)) |
| { |
| const char *strtab; |
| |
| strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]); |
| _dl_error_printf ("\ |
| %s: Symbol `%s' has different size in shared object, consider re-linking\n", |
| _dl_argv[0] ?: "<program name unknown>", |
| strtab + refsym->st_name); |
| } |
| memcpy (reloc_addr, (void *) value, MIN (sym->st_size, |
| refsym->st_size)); |
| break; |
| default: |
| _dl_reloc_bad_type (map, r_type, 0); |
| break; |
| } |
| #endif |
| } |
| } |
| |
| static inline void __attribute__ ((unused)) |
| elf_machine_rel_relative (Elf32_Addr l_addr, const Elf32_Rel *reloc, |
| Elf32_Addr *const reloc_addr) |
| { |
| assert (ELF32_R_TYPE (reloc->r_info) == R_386_RELATIVE); |
| *reloc_addr += l_addr; |
| } |
| |
| static inline void |
| elf_machine_lazy_rel (struct link_map *map, |
| Elf32_Addr l_addr, const Elf32_Rel *reloc) |
| { |
| Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset); |
| const unsigned int r_type = ELF32_R_TYPE (reloc->r_info); |
| /* Check for unexpected PLT reloc type. */ |
| if (__builtin_expect (r_type == R_386_JMP_SLOT, 1)) |
| *reloc_addr += l_addr; |
| else |
| _dl_reloc_bad_type (map, r_type, 1); |
| } |
| |
| #endif /* RESOLVE */ |