/* Machine-dependent ELF dynamic relocation inline functions. SPARC version. Copyright (C) 1996, 1997 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define ELF_MACHINE_NAME "sparc" #include #include #include #include /* Some SPARC opcodes we need to use for self-modifying code. */ #define OPCODE_NOP 0x01000000 /* nop */ #define OPCODE_CALL 0x40000000 /* call ?; add PC-rel word address */ #define OPCODE_SETHI_G1 0x03000000 /* sethi ?, %g1; add value>>10 */ #define OPCODE_JMP_G1 0x81c06000 /* jmp %g1+?; add lo 10 bits of value */ #define OPCODE_SAVE_SP 0x9de3bfa8 /* save %sp, -(16+6)*4, %sp */ /* Return nonzero iff E_MACHINE is compatible with the running host. */ static inline int elf_machine_matches_host (Elf32_Half e_machine) { return e_machine == EM_SPARC; } /* 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 elf_machine_dynamic (void) { register Elf32_Addr *got asm ("%l7"); return *got; } /* Return the run-time load address of the shared object. */ static inline Elf32_Addr elf_machine_load_address (void) { register Elf32_Addr pc __asm("%o7"), pic __asm("%l7"), got; /* Utilize the fact that a local .got entry will be partially initialized at startup awaiting its RELATIVE fixup. */ __asm("sethi %%hi(.Load_address),%1\n" ".Load_address:\n\t" "call 1f\n\t" "or %1,%%lo(.Load_address),%1\n" "1:\tld [%2+%1],%1" : "=r"(pc), "=r"(got) : "r"(pic)); return pc - got; } /* 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 elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) { Elf32_Addr *plt; extern void _dl_runtime_resolve (Elf32_Word); if (l->l_info[DT_JMPREL] && lazy) { /* The entries for functions in the PLT have not yet been filled in. Their initial contents will arrange when called to set the high 22 bits of %g1 with an offset into the .rela.plt section and jump to the beginning of the PLT. */ plt = (Elf32_Addr *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr); /* The beginning of the PLT does: save %sp, -64, %sp pltpc: call _dl_runtime_resolve nop .word MAP This saves the register window containing the arguments, and the PC value (pltpc) implicitly saved in %o7 by the call points near the location where we store the link_map pointer for this object. */ plt[0] = OPCODE_SAVE_SP; /* Construct PC-relative word address. */ plt[1] = OPCODE_CALL | (((Elf32_Addr) &_dl_runtime_resolve - (Elf32_Addr) &plt[1]) >> 2); plt[2] = OPCODE_NOP; /* Fill call delay slot. */ plt[3] = (Elf32_Addr) l; } return lazy; } /* 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 ("\ .globl _dl_runtime_resolve .type _dl_runtime_resolve, @function _dl_runtime_resolve: /* Set up the arguments to fixup -- %o0 = link_map out of plt0 %o1 = offset of reloc entry */ ld [%o7 + 8], %o0 srl %g1, 10, %o1 call fixup sub %o1, 4*12, %o1 jmp %o0 restore .size _dl_runtime_resolve, . - _dl_runtime_resolve"); /* The address of the JMP_SLOT reloc is the .plt entry, thus we don't dereference the reloc's addr to get the final destination. Ideally there would be a generic way to return the value of the symbol from elf_machine_relplt, but as it is, the address of the .plt entry is good enough. */ #define ELF_FIXUP_RETURN_VALUE(map, result) ((Elf32_Addr) &(result)) /* Nonzero iff TYPE should not be allowed to resolve to one of the main executable's symbols, as for a COPY reloc. */ #define elf_machine_lookup_noexec_p(type) ((type) == R_SPARC_COPY) /* Nonzero iff TYPE describes relocation of a PLT entry, so PLT entries should not be allowed to define the value. */ #define elf_machine_lookup_noplt_p(type) ((type) == R_SPARC_JMP_SLOT) /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */ #define ELF_MACHINE_RELOC_NOPLT R_SPARC_JMP_SLOT /* The SPARC never uses Elf32_Rel relocations. */ #define ELF_MACHINE_NO_REL 1 /* The SPARC overlaps DT_RELA and DT_PLTREL. */ #define ELF_MACHINE_PLTREL_OVERLAP 1 /* The PLT uses Elf32_Rela relocs. */ #define elf_machine_relplt elf_machine_rela /* 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 .type _start,@function _start: /* Allocate space for functions to drop their arguments. */ sub %sp, 6*4, %sp /* Pass pointer to argument block to _dl_start. */ call _dl_start add %sp, 22*4, %o0 /* FALTHRU */ .globl _dl_start_user .type _dl_start_user,@function _dl_start_user: /* Load the PIC register. */ 1: call 2f sethi %hi(_GLOBAL_OFFSET_TABLE_-(1b-.)), %l7 2: or %l7, %lo(_GLOBAL_OFFSET_TABLE_-(1b-.)), %l7 add %l7, %o7, %l7 /* Save the user entry point address in %l0 */ mov %o0, %l0 /* See if we were run as a command with the executable file name as an extra leading argument. If so, adjust the contents of the stack. */ sethi %hi(_dl_skip_args), %g2 or %g2, %lo(_dl_skip_args), %g2 ld [%l7+%g2], %i0 ld [%i0], %i0 tst %i0 beq 3f nop /* Find out how far to shift. */ ld [%sp+22*4], %i1 /* load argc */ sub %i1, %i0, %i1 sll %i0, 2, %i2 st %i1, [%sp+22*4] add %sp, 23*4, %i1 add %i1, %i2, %i2 /* Copy down argv */ 21: ld [%i2], %i3 add %i2, 4, %i2 tst %i3 st %i3, [%i1] bne 21b add %i1, 4, %i1 /* Copy down env */ 22: ld [%i2], %i3 add %i2, 4, %i2 tst %i3 st %i3, [%i1] bne 22b add %i1, 4, %i1 /* Copy down auxiliary table. */ 23: ld [%i2], %i3 ld [%i2+4], %i4 add %i2, 8, %i2 tst %i3 st %i3, [%i1] st %i4, [%i1+4] bne 23b add %i1, 8, %i1 /* Load _dl_default_scope[2] to pass to _dl_init_next. */ 3: sethi %hi(_dl_default_scope), %g1 or %g1, %lo(_dl_default_scope), %g1 ld [%l7+%g1], %l1 ld [%l1+2*4], %l1 /* Call _dl_init_next to return the address of an initializer to run. */ 4: call _dl_init_next mov %l1, %o0 tst %o0 beq 5f nop jmpl %o0, %o7 nop ba,a 4b /* Clear the startup flag. */ 5: sethi %hi(_dl_starting_up), %g1 or %g1, %lo(_dl_starting_up), %g1 ld [%l7+%g1], %g1 st %g0, [%g1] /* Pass our finalizer function to the user in %g1. */ sethi %hi(_dl_fini), %g1 or %g1, %lo(_dl_fini), %g1 ld [%l7+%g1], %g1 /* Jump to the user's entry point and deallocate the extra stack we got. */ jmp %l0 add %sp, 6*4, %sp .size _dl_start_user,.-_dl_start_user .previous"); #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_rela (struct link_map *map, const Elf32_Rela *reloc, const Elf32_Sym *sym, const struct r_found_version *version, Elf32_Addr *const reloc_addr) { extern unsigned long _dl_hwcap; if (ELF32_R_TYPE (reloc->r_info) == R_SPARC_RELATIVE) { #ifndef RTLD_BOOTSTRAP if (map != &_dl_rtld_map) /* Already done in rtld itself. */ #endif *reloc_addr += map->l_addr + reloc->r_addend; } else { const Elf32_Sym *const refsym = sym; Elf32_Addr value; if (sym->st_shndx != SHN_UNDEF && ELF32_ST_BIND (sym->st_info) == STB_LOCAL) value = map->l_addr; else { value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info)); if (sym) value += sym->st_value; } value += reloc->r_addend; /* Assume copy relocs have zero addend. */ switch (ELF32_R_TYPE (reloc->r_info)) { case R_SPARC_COPY: #ifndef RTLD_BOOTSTRAP if (sym->st_size > refsym->st_size || (_dl_verbose && sym->st_size < refsym->st_size)) { extern char **_dl_argv; const char *strtab; strtab = ((void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr); _dl_sysdep_error (_dl_argv[0] ?: "", ": Symbol `", strtab + refsym->st_name, "' has different size in shared object, " "consider re-linking\n", NULL); } memcpy (reloc_addr, (void *) value, MIN (sym->st_size, refsym->st_size)); #endif break; case R_SPARC_GLOB_DAT: case R_SPARC_32: *reloc_addr = value; break; case R_SPARC_JMP_SLOT: /* For thread safety, write the instructions from the bottom and flush before we overwrite the critical "b,a". */ reloc_addr[2] = OPCODE_JMP_G1 | (value & 0x3ff); if (_dl_hwcap & HWCAP_SPARC_FLUSH) __asm __volatile ("flush %0+8" : : "r"(reloc_addr)); reloc_addr[1] = OPCODE_SETHI_G1 | (value >> 10); if (_dl_hwcap & HWCAP_SPARC_FLUSH) __asm __volatile ("flush %0+4" : : "r"(reloc_addr)); break; case R_SPARC_8: *(char *) reloc_addr = value; break; case R_SPARC_16: *(short *) reloc_addr = value; break; case R_SPARC_DISP8: *(char *) reloc_addr = (value - (Elf32_Addr) reloc_addr); break; case R_SPARC_DISP16: *(short *) reloc_addr = (value - (Elf32_Addr) reloc_addr); break; case R_SPARC_DISP32: *reloc_addr = (value - (Elf32_Addr) reloc_addr); break; case R_SPARC_LO10: *reloc_addr = (*reloc_addr & ~0x3ff) | (value & 0x3ff); break; case R_SPARC_WDISP30: *reloc_addr = ((*reloc_addr & 0xc0000000) | ((value - (unsigned int) reloc_addr) >> 2)); break; case R_SPARC_HI22: *reloc_addr = (*reloc_addr & 0xffc00000) | (value >> 10); break; case R_SPARC_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) { switch (ELF32_R_TYPE (reloc->r_info)) { case R_SPARC_NONE: break; case R_SPARC_JMP_SLOT: break; default: assert (! "unexpected PLT reloc type"); break; } } #endif /* RESOLVE */