diff options
Diffstat (limited to 'sysdeps/powerpc/dl-machine.h')
| -rw-r--r-- | sysdeps/powerpc/dl-machine.h | 55 |
1 files changed, 43 insertions, 12 deletions
diff --git a/sysdeps/powerpc/dl-machine.h b/sysdeps/powerpc/dl-machine.h index c9d1d73..74436d1 100644 --- a/sysdeps/powerpc/dl-machine.h +++ b/sysdeps/powerpc/dl-machine.h @@ -57,10 +57,11 @@ #define OPCODE_LI(rd,simm) OPCODE_ADDI(rd,0,simm) #define OPCODE_SLWI(ra,rs,sh) OPCODE_RLWINM(ra,rs,sh,0,31-sh) -#define PPC_DCBST(where) asm __volatile__ ("dcbst 0,%0" : : "r"(where)) -#define PPC_SYNC asm __volatile__ ("sync") -#define PPC_ISYNC asm __volatile__ ("sync; isync") -#define PPC_ICBI(where) asm __volatile__ ("icbi 0,%0" : : "r"(where)) +#define PPC_DCBST(where) asm volatile ("dcbst 0,%0" : : "r"(where)) +#define PPC_SYNC asm volatile ("sync") +#define PPC_ISYNC asm volatile ("sync; isync") +#define PPC_ICBI(where) asm volatile ("icbi 0,%0" : : "r"(where)) +#define PPC_DIE asm volatile ("tweq 0,0") /* Use this when you've modified some code, but it won't be in the instruction fetch queue (or when it doesn't matter if it is). */ @@ -147,9 +148,9 @@ elf_machine_load_address (void) /* 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. */ +/* 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. */ #define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\ .section \".text\" .align 2 @@ -511,11 +512,14 @@ elf_machine_lazy_rel (struct link_map *map, const Elf32_Rela *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) + Elf32_Addr *const reloc_addr) { +#ifndef RTLD_BOOTSTRAP const Elf32_Sym *const refsym = sym; +#endif Elf32_Word loadbase, finaladdr; const int rinfo = ELF32_R_TYPE (reloc->r_info); + extern char **_dl_argv; if (rinfo == R_PPC_NONE) return; @@ -598,7 +602,6 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, 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 @@ -631,11 +634,31 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, plt = (Elf32_Word *)((char *)map->l_addr + map->l_info[DT_PLTGOT]->d_un.d_val); index = (reloc_addr - plt - PLT_INITIAL_ENTRY_WORDS)/2; - if (index >= PLT_DOUBLE_SIZE) { /* Slots greater than or equal to 2^13 have 4 words available instead of two. */ + /* FIXME: There are some possible race conditions in this code, + when called from 'fixup'. + + 1) Suppose that a lazy PLT entry is executing, a + context switch between threads (or a signal) occurs, + and the new thread or signal handler calls the same + lazy PLT entry. Then the PLT entry would be changed + while it's being run, which will cause a segfault + (almost always). + + 2) Suppose the reverse: that a lazy PLT entry is + being updated, a context switch occurs, and the new + code calls the lazy PLT entry that is being updated. + Then the half-fixed PLT entry will be executed, which + will also almost always cause a segfault. + + These problems don't happen with the 2-word entries, because + only one of the two instructions are changed when a lazy + entry is retargeted at the actual PLT entry; the li + instruction stays the same (we have to update it anyway, + because we might not be updating a lazy PLT entry). */ reloc_addr[0] = OPCODE_LI (11, finaladdr); reloc_addr[1] = OPCODE_ADDIS (11, 11, finaladdr + 0x8000 >> 16); reloc_addr[2] = OPCODE_MTCTR (11); @@ -648,19 +671,27 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val / sizeof(Elf32_Rela)); + plt[index+PLT_DATA_START_WORDS (num_plt_entries)] = finaladdr; reloc_addr[0] = OPCODE_LI (11, index*4); reloc_addr[1] = OPCODE_B (-(4*(index*2 + 1 - PLT_LONGBRANCH_ENTRY_WORDS + PLT_INITIAL_ENTRY_WORDS))); - plt[index+PLT_DATA_START_WORDS (num_plt_entries)] = finaladdr; } } MODIFIED_CODE (reloc_addr); } else - assert (! "unexpected dynamic reloc type"); + { +#ifdef RTLD_BOOTSTRAP + PPC_DIE; /* There is no point calling _dl_sysdep_error, it + almost certainly hasn't been relocated properly. */ +#else + _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>", + ": Unknown relocation type\n", NULL); +#endif + } if (rinfo == R_PPC_ADDR16_LO || rinfo == R_PPC_ADDR16_HI || |