diff options
Diffstat (limited to 'gdb/mips-linux-tdep.c')
| -rw-r--r-- | gdb/mips-linux-tdep.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/gdb/mips-linux-tdep.c b/gdb/mips-linux-tdep.c index a7ee145a951..fb7601b752a 100644 --- a/gdb/mips-linux-tdep.c +++ b/gdb/mips-linux-tdep.c @@ -27,6 +27,7 @@ #include "mips-tdep.h" #include "gdb_string.h" #include "gdb_assert.h" +#include "frame.h" /* Copied from <asm/elf.h>. */ #define ELF_NGREG 45 @@ -676,6 +677,125 @@ init_register_addr_data (struct gdbarch *gdbarch) return 0; } +/* Check the code at PC for a dynamic linker lazy resolution stub. Because + they aren't in the .plt section, we pattern-match on the code generated + by GNU ld. They look like this: + + lw t9,0x8010(gp) + addu t7,ra + jalr t9,ra + addiu t8,zero,INDEX + + (with the appropriate doubleword instructions for N64). Also return the + dynamic symbol index used in the last instruction. */ + +static int +mips_linux_in_dynsym_stub (CORE_ADDR pc, char *name) +{ + unsigned char buf[28], *p; + ULONGEST insn, insn1; + int n64 = (mips_abi (current_gdbarch) == MIPS_ABI_N64); + + read_memory (pc - 12, buf, 28); + + if (n64) + { + /* ld t9,0x8010(gp) */ + insn1 = 0xdf998010; + } + else + { + /* lw t9,0x8010(gp) */ + insn1 = 0x8f998010; + } + + p = buf + 12; + while (p >= buf) + { + insn = extract_unsigned_integer (p, 4); + if (insn == insn1) + break; + p -= 4; + } + if (p < buf) + return 0; + + insn = extract_unsigned_integer (p + 4, 4); + if (n64) + { + /* daddu t7,ra */ + if (insn != 0x03e0782d) + return 0; + } + else + { + /* addu t7,ra */ + if (insn != 0x03e07821) + return 0; + } + + insn = extract_unsigned_integer (p + 8, 4); + /* jalr t9,ra */ + if (insn != 0x0320f809) + return 0; + + insn = extract_unsigned_integer (p + 12, 4); + if (n64) + { + /* daddiu t8,zero,0 */ + if ((insn & 0xffff0000) != 0x64180000) + return 0; + } + else + { + /* addiu t8,zero,0 */ + if ((insn & 0xffff0000) != 0x24180000) + return 0; + } + + return (insn & 0xffff); +} + +/* Return non-zero iff PC belongs to the dynamic linker resolution code + or to a stub. */ + +int +mips_linux_in_dynsym_resolve_code (CORE_ADDR pc) +{ + /* Check whether PC is in the dynamic linker. This also checks whether + it is in the .plt section, which MIPS does not use. */ + if (in_solib_dynsym_resolve_code (pc)) + return 1; + + /* Pattern match for the stub. It would be nice if there were a more + efficient way to avoid this check. */ + if (mips_linux_in_dynsym_stub (pc, NULL)) + return 1; + + return 0; +} + +/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c, + and glibc_skip_solib_resolver in glibc-tdep.c. The normal glibc + implementation of this triggers at "fixup" from the same objfile as + "_dl_runtime_resolve"; MIPS/Linux can trigger at "__dl_runtime_resolve" + directly. An unresolved PLT entry will point to _dl_runtime_resolve, + which will first call __dl_runtime_resolve, and then pass control to + the resolved function. */ + +static CORE_ADDR +mips_linux_skip_resolver (struct gdbarch *gdbarch, CORE_ADDR pc) +{ + struct minimal_symbol *resolver; + + resolver = lookup_minimal_symbol ("__dl_runtime_resolve", NULL, NULL); + + if (resolver && SYMBOL_VALUE_ADDRESS (resolver) == pc) + return frame_pc_unwind (get_current_frame ()); + + return 0; +} + static void mips_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { @@ -709,6 +829,12 @@ mips_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) internal_error (__FILE__, __LINE__, "can't handle ABI"); break; } + + set_gdbarch_skip_solib_resolver (gdbarch, mips_linux_skip_resolver); + + /* This overrides the MIPS16 stub support from mips-tdep. But no one uses + MIPS16 on Linux yet, so this isn't much of a loss. */ + set_gdbarch_in_solib_call_trampoline (gdbarch, mips_linux_in_dynsym_stub); } void |