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Diffstat (limited to 'sysdeps/powerpc/powerpc32/dl-machine.h')
| -rw-r--r-- | sysdeps/powerpc/powerpc32/dl-machine.h | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/dl-machine.h b/sysdeps/powerpc/powerpc32/dl-machine.h new file mode 100644 index 0000000000..34858e5a4b --- /dev/null +++ b/sysdeps/powerpc/powerpc32/dl-machine.h @@ -0,0 +1,418 @@ +/* Machine-dependent ELF dynamic relocation inline functions. PowerPC version. + Copyright (C) 1995-2000,01,02 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 "powerpc" + +#include <assert.h> + +/* Return nonzero iff ELF header is compatible with the running host. */ +static inline int +elf_machine_matches_host (const Elf32_Ehdr *ehdr) +{ + return ehdr->e_machine == EM_PPC; +} + + +/* Return the link-time address of _DYNAMIC, stored as + the first value in the GOT. */ +static inline Elf32_Addr +elf_machine_dynamic (void) +{ + Elf32_Addr *got; + asm (" bl _GLOBAL_OFFSET_TABLE_-4@local" + : "=l"(got)); + return *got; +} + +/* Return the run-time load address of the shared object. */ +static inline Elf32_Addr +elf_machine_load_address (void) +{ + unsigned int *got; + unsigned int *branchaddr; + + /* This is much harder than you'd expect. Possibly I'm missing something. + The 'obvious' way: + + Apparently, "bcl 20,31,$+4" is what should be used to load LR + with the address of the next instruction. + I think this is so that machines that do bl/blr pairing don't + get confused. + + asm ("bcl 20,31,0f ;" + "0: mflr 0 ;" + "lis %0,0b@ha;" + "addi %0,%0,0b@l;" + "subf %0,%0,0" + : "=b" (addr) : : "r0", "lr"); + + doesn't work, because the linker doesn't have to (and in fact doesn't) + update the @ha and @l references; the loader (which runs after this + code) will do that. + + Instead, we use the following trick: + + The linker puts the _link-time_ address of _DYNAMIC at the first + word in the GOT. We could branch to that address, if we wanted, + by using an @local reloc; the linker works this out, so it's safe + to use now. We can't, of course, actually branch there, because + we'd cause an illegal instruction exception; so we need to compute + the address ourselves. That gives us the following code: */ + + /* Get address of the 'b _DYNAMIC@local'... */ + asm ("bl 0f ;" + "b _DYNAMIC@local;" + "0:" + : "=l"(branchaddr)); + + /* ... and the address of the GOT. */ + asm (" bl _GLOBAL_OFFSET_TABLE_-4@local" + : "=l"(got)); + + /* So now work out the difference between where the branch actually points, + and the offset of that location in memory from the start of the file. */ + return ((Elf32_Addr)branchaddr - *got + + ((int)(*branchaddr << 6 & 0xffffff00) >> 6)); +} + +#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */ + +/* The PLT uses Elf32_Rela relocs. */ +#define elf_machine_relplt elf_machine_rela + +/* This code is used in dl-runtime.c to call the `fixup' function + and then redirect to the address it returns. It is called + from code built in the PLT by elf_machine_runtime_setup. */ +#if !defined PROF +#define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\n\ + .section \".text\" \n\ + .align 2 \n\ + .globl _dl_runtime_resolve \n\ + .type _dl_runtime_resolve,@function \n\ +_dl_runtime_resolve: \n\ + # We need to save the registers used to pass parameters, and register 0,\n\ + # which is used by _mcount; the registers are saved in a stack frame.\n\ + stwu 1,-64(1) \n\ + stw 0,12(1) \n\ + stw 3,16(1) \n\ + stw 4,20(1) \n\ + # The code that calls this has put parameters for `fixup' in r12 and r11.\n\ + mr 3,12 \n\ + stw 5,24(1) \n\ + mr 4,11 \n\ + stw 6,28(1) \n\ + mflr 0 \n\ + # We also need to save some of the condition register fields.\n\ + stw 7,32(1) \n\ + stw 0,48(1) \n\ + stw 8,36(1) \n\ + mfcr 0 \n\ + stw 9,40(1) \n\ + stw 10,44(1) \n\ + stw 0,8(1) \n\ + bl fixup@local \n\ + # 'fixup' returns the address we want to branch to.\n\ + mtctr 3 \n\ + # Put the registers back...\n\ + lwz 0,48(1) \n\ + lwz 10,44(1) \n\ + lwz 9,40(1) \n\ + mtlr 0 \n\ + lwz 8,36(1) \n\ + lwz 0,8(1) \n\ + lwz 7,32(1) \n\ + lwz 6,28(1) \n\ + mtcrf 0xFF,0 \n\ + lwz 5,24(1) \n\ + lwz 4,20(1) \n\ + lwz 3,16(1) \n\ + lwz 0,12(1) \n\ + # ...unwind the stack frame, and jump to the PLT entry we updated.\n\ + addi 1,1,64 \n\ + bctr \n\ + .size _dl_runtime_resolve,.-_dl_runtime_resolve \n\ + \n\ + .align 2 \n\ + .globl _dl_prof_resolve \n\ + .type _dl_prof_resolve,@function \n\ +_dl_prof_resolve: \n\ + # We need to save the registers used to pass parameters, and register 0,\n\ + # which is used by _mcount; the registers are saved in a stack frame.\n\ + stwu 1,-64(1) \n\ + stw 0,12(1) \n\ + stw 3,16(1) \n\ + stw 4,20(1) \n\ + # The code that calls this has put parameters for `fixup' in r12 and r11.\n\ + mr 3,12 \n\ + stw 5,24(1) \n\ + mr 4,11 \n\ + stw 6,28(1) \n\ + mflr 5 \n\ + # We also need to save some of the condition register fields.\n\ + stw 7,32(1) \n\ + stw 5,48(1) \n\ + stw 8,36(1) \n\ + mfcr 0 \n\ + stw 9,40(1) \n\ + stw 10,44(1) \n\ + stw 0,8(1) \n\ + bl profile_fixup@local \n\ + # 'fixup' returns the address we want to branch to.\n\ + mtctr 3 \n\ + # Put the registers back...\n\ + lwz 0,48(1) \n\ + lwz 10,44(1) \n\ + lwz 9,40(1) \n\ + mtlr 0 \n\ + lwz 8,36(1) \n\ + lwz 0,8(1) \n\ + lwz 7,32(1) \n\ + lwz 6,28(1) \n\ + mtcrf 0xFF,0 \n\ + lwz 5,24(1) \n\ + lwz 4,20(1) \n\ + lwz 3,16(1) \n\ + lwz 0,12(1) \n\ + # ...unwind the stack frame, and jump to the PLT entry we updated.\n\ + addi 1,1,64 \n\ + bctr \n\ + .size _dl_prof_resolve,.-_dl_prof_resolve \n\ + # Undo '.section text'.\n\ + .previous \n\ +"); +#else +# define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\n\ + .section \".text\" \n\ + .align 2 \n\ + .globl _dl_runtime_resolve \n\ + .globl _dl_prof_resolve \n\ + .type _dl_runtime_resolve,@function \n\ + .type _dl_prof_resolve,@function \n\ +_dl_runtime_resolve: \n\ +_dl_prof_resolve: \n\ + # We need to save the registers used to pass parameters, and register 0,\n\ + # which is used by _mcount; the registers are saved in a stack frame.\n\ + stwu 1,-64(1) \n\ + stw 0,12(1) \n\ + stw 3,16(1) \n\ + stw 4,20(1) \n\ + # The code that calls this has put parameters for `fixup' in r12 and r11.\n\ + mr 3,12 \n\ + stw 5,24(1) \n\ + mr 4,11 \n\ + stw 6,28(1) \n\ + mflr 0 \n\ + # We also need to save some of the condition register fields.\n\ + stw 7,32(1) \n\ + stw 0,48(1) \n\ + stw 8,36(1) \n\ + mfcr 0 \n\ + stw 9,40(1) \n\ + stw 10,44(1) \n\ + stw 0,8(1) \n\ + bl fixup@local \n\ + # 'fixup' returns the address we want to branch to.\n\ + mtctr 3 \n\ + # Put the registers back...\n\ + lwz 0,48(1) \n\ + lwz 10,44(1) \n\ + lwz 9,40(1) \n\ + mtlr 0 \n\ + lwz 8,36(1) \n\ + lwz 0,8(1) \n\ + lwz 7,32(1) \n\ + lwz 6,28(1) \n\ + mtcrf 0xFF,0 \n\ + lwz 5,24(1) \n\ + lwz 4,20(1) \n\ + lwz 3,16(1) \n\ + lwz 0,12(1) \n\ + # ...unwind the stack frame, and jump to the PLT entry we updated.\n\ + addi 1,1,64 \n\ + bctr \n\ + .size _dl_runtime_resolve,.-_dl_runtime_resolve \n\ +"); +#endif + +/* Mask identifying addresses reserved for the user program, + where the dynamic linker should not map anything. */ +#define ELF_MACHINE_USER_ADDRESS_MASK 0xf0000000UL + +/* The actual _start code is in dl-start.S. Use a really + ugly bit of assembler to let dl-start.o see _dl_start. */ +#define RTLD_START asm (".globl _dl_start"); + +/* Decide where a relocatable object should be loaded. */ +extern ElfW(Addr) +__elf_preferred_address(struct link_map *loader, size_t maplength, + ElfW(Addr) mapstartpref); +#define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) \ + __elf_preferred_address (loader, maplength, mapstartpref) + +/* 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. */ +/* We never want to use a PLT entry as the destination of a + reloc, when what is being relocated is a branch. This is + partly for efficiency, but mostly so we avoid loops. */ +#define elf_machine_type_class(type) \ + ((((type) == R_PPC_JMP_SLOT \ + || (type) == R_PPC_REL24 \ + || (type) == R_PPC_ADDR24) * ELF_RTYPE_CLASS_PLT) \ + | (((type) == R_PPC_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_PPC_JMP_SLOT + +/* The PowerPC never uses 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. + Also install a small trampoline to be used by entries that have + been relocated to an address too far away for a single branch. */ +extern int __elf_machine_runtime_setup (struct link_map *map, + int lazy, int profile); +#define elf_machine_runtime_setup __elf_machine_runtime_setup + +static inline void +elf_machine_lazy_rel (struct link_map *map, + Elf32_Addr l_addr, const Elf32_Rela *reloc) +{ + /* elf_machine_runtime_setup handles this. */ +} + +/* Change the PLT entry whose reloc is 'reloc' to call the actual routine. */ +extern Elf32_Addr __elf_machine_fixup_plt (struct link_map *map, + const Elf32_Rela *reloc, + Elf32_Addr *reloc_addr, + Elf32_Addr finaladdr); + +static inline Elf32_Addr +elf_machine_fixup_plt (struct link_map *map, lookup_t t, + const Elf32_Rela *reloc, + Elf32_Addr *reloc_addr, Elf64_Addr finaladdr) +{ + return __elf_machine_fixup_plt (map, reloc, reloc_addr, finaladdr); +} + +/* Return the final value of a plt relocation. */ +static inline Elf32_Addr +elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc, + Elf32_Addr value) +{ + return value + reloc->r_addend; +} + +#endif /* dl_machine_h */ + +#ifdef RESOLVE + +/* Do the actual processing of a reloc, once its target address + has been determined. */ +extern void __process_machine_rela (struct link_map *map, + const Elf32_Rela *reloc, + const Elf32_Sym *sym, + const Elf32_Sym *refsym, + Elf32_Addr *const reloc_addr, + Elf32_Addr finaladdr, + int rinfo); + +/* Perform the relocation specified by RELOC and SYM (which is fully resolved). + LOADADDR is the load address of the object; INFO is an array indexed + by DT_* of the .dynamic section info. */ + +inline void +elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, + const Elf32_Sym *sym, const struct r_found_version *version, + Elf32_Addr *const reloc_addr) +{ + const Elf32_Sym *const refsym = sym; + Elf32_Word finaladdr; + const int rinfo = ELF32_R_TYPE (reloc->r_info); + +#ifndef RESOLVE_CONFLICT_FIND_MAP + if (__builtin_expect (rinfo == R_PPC_NONE, 0)) + return; + + /* The condition on the next two lines is a hack around a bug in Solaris + tools on Sparc. It's not clear whether it should really be here at all, + but if not the binutils need to be changed. */ + if (rinfo == R_PPC_RELATIVE + || (sym->st_shndx != SHN_UNDEF + && ELF32_ST_BIND (sym->st_info) == STB_LOCAL)) + { + /* Has already been relocated. */ + Elf32_Word loadbase = map->l_addr; + finaladdr = loadbase + reloc->r_addend; + } + else + { + Elf32_Word loadbase + = (Elf32_Word) (char *) (RESOLVE (&sym, version, + ELF32_R_TYPE(reloc->r_info))); + if (sym == NULL) + { + /* Weak symbol that wasn't actually defined anywhere. */ + assert (loadbase == 0); + finaladdr = reloc->r_addend; + } + else + finaladdr = (loadbase + (Elf32_Word) (char *) sym->st_value + + reloc->r_addend); + } +#else + finaladdr = reloc->r_addend; + if (rinfo == R_PPC_JMP_SLOT) + RESOLVE_CONFLICT_FIND_MAP (map, reloc_addr); +#endif + + /* A small amount of code is duplicated here for speed. In libc, + more than 90% of the relocs are R_PPC_RELATIVE; in the X11 shared + libraries, 60% are R_PPC_RELATIVE, 24% are R_PPC_GLOB_DAT or + R_PPC_ADDR32, and 16% are R_PPC_JMP_SLOT (which this routine + wouldn't usually handle). As an bonus, doing this here allows + the switch statement in __process_machine_rela to work. */ + if (rinfo == R_PPC_RELATIVE + || rinfo == R_PPC_GLOB_DAT + || rinfo == R_PPC_ADDR32) + { + *reloc_addr = finaladdr; + } + else + __process_machine_rela (map, reloc, sym, refsym, + reloc_addr, finaladdr, rinfo); +} + +static inline void +elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc, + Elf32_Addr *const reloc_addr) +{ + *reloc_addr = l_addr + reloc->r_addend; +} + +/* The SVR4 ABI specifies that the JMPREL relocs must be inside the + DT_RELA table. */ +#define ELF_MACHINE_PLTREL_OVERLAP 1 + +#endif /* RESOLVE */ |