diff options
Diffstat (limited to 'gdb/i386nbsd-tdep.c')
| -rw-r--r-- | gdb/i386nbsd-tdep.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/gdb/i386nbsd-tdep.c b/gdb/i386nbsd-tdep.c index 634101ad35f..8d32a03974d 100644 --- a/gdb/i386nbsd-tdep.c +++ b/gdb/i386nbsd-tdep.c @@ -23,8 +23,13 @@ #include "gdbtypes.h" #include "gdbcore.h" #include "regcache.h" +#include "arch-utils.h" +#include "i386-tdep.h" #include "i387-tdep.h" +#include "nbsd-tdep.h" + +#include "solib-svr4.h" /* Map a GDB register number to an offset in the reg structure. */ static int regmap[] = @@ -137,9 +142,161 @@ static struct core_fns i386nbsd_elfcore_fns = NULL /* next */ }; +/* Under NetBSD/i386, signal handler invocations can be identified by the + designated code sequence that is used to return from a signal handler. + In particular, the return address of a signal handler points to the + following code sequence: + + leal 0x10(%esp), %eax + pushl %eax + pushl %eax + movl $0x127, %eax # __sigreturn14 + int $0x80 + + Each instruction has a unique encoding, so we simply attempt to match + the instruction the PC is pointing to with any of the above instructions. + If there is a hit, we know the offset to the start of the designated + sequence and can then check whether we really are executing in the + signal trampoline. If not, -1 is returned, otherwise the offset from the + start of the return sequence is returned. */ +#define RETCODE_INSN1 0x8d +#define RETCODE_INSN2 0x50 +#define RETCODE_INSN3 0x50 +#define RETCODE_INSN4 0xb8 +#define RETCODE_INSN5 0xcd + +#define RETCODE_INSN2_OFF 4 +#define RETCODE_INSN3_OFF 5 +#define RETCODE_INSN4_OFF 6 +#define RETCODE_INSN5_OFF 11 + +static const unsigned char sigtramp_retcode[] = +{ + RETCODE_INSN1, 0x44, 0x24, 0x10, + RETCODE_INSN2, + RETCODE_INSN3, + RETCODE_INSN4, 0x27, 0x01, 0x00, 0x00, + RETCODE_INSN5, 0x80, +}; + +static LONGEST +i386nbsd_sigtramp_offset (CORE_ADDR pc) +{ + unsigned char ret[sizeof(sigtramp_retcode)], insn; + LONGEST off; + int i; + + if (read_memory_nobpt (pc, &insn, 1) != 0) + return -1; + + switch (insn) + { + case RETCODE_INSN1: + off = 0; + break; + + case RETCODE_INSN2: + /* INSN2 and INSN3 are the same. Read at the location of PC+1 + to determine if we're actually looking at INSN2 or INSN3. */ + if (read_memory_nobpt (pc + 1, &insn, 1) != 0) + return -1; + + if (insn == RETCODE_INSN3) + off = RETCODE_INSN2_OFF; + else + off = RETCODE_INSN3_OFF; + break; + + case RETCODE_INSN4: + off = RETCODE_INSN4_OFF; + break; + + case RETCODE_INSN5: + off = RETCODE_INSN5_OFF; + break; + + default: + return -1; + } + + pc -= off; + + if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0) + return -1; + + if (memcmp (ret, sigtramp_retcode, sizeof (ret)) == 0) + return off; + + return -1; +} + +static int +i386nbsd_pc_in_sigtramp (CORE_ADDR pc, char *name) +{ + + return (nbsd_pc_in_sigtramp (pc, name) + || i386nbsd_sigtramp_offset (pc) >= 0); +} + +/* From <machine/signal.h>. */ +int i386nbsd_sc_pc_offset = 44; +int i386nbsd_sc_sp_offset = 56; + +static void +i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) +{ + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + + /* Obviously NetBSD is BSD-based. */ + i386bsd_init_abi (info, gdbarch); + + /* NetBSD has different signal trampoline conventions. */ + set_gdbarch_pc_in_sigtramp (gdbarch, i386nbsd_pc_in_sigtramp); + + /* NetBSD uses -freg-struct-return by default. */ + tdep->struct_return = reg_struct_return; + + /* NetBSD has a `struct sigcontext' that's different from the + origional 4.3 BSD. */ + tdep->sc_pc_offset = i386nbsd_sc_pc_offset; + tdep->sc_sp_offset = i386nbsd_sc_sp_offset; +} + +/* NetBSD ELF. */ +static void +i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) +{ + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + + /* It's still NetBSD. */ + i386nbsd_init_abi (info, gdbarch); + + /* But ELF-based. */ + i386_elf_init_abi (info, gdbarch); + + /* NetBSD ELF uses SVR4-style shared libraries. */ + set_gdbarch_in_solib_call_trampoline (gdbarch, + generic_in_solib_call_trampoline); + set_solib_svr4_fetch_link_map_offsets (gdbarch, + nbsd_ilp32_solib_svr4_fetch_link_map_offsets); + + /* NetBSD ELF uses -fpcc-struct-return by default. */ + tdep->struct_return = pcc_struct_return; + + /* We support the SSE registers on NetBSD ELF. */ + tdep->num_xmm_regs = I386_NUM_XREGS - 1; + set_gdbarch_num_regs (gdbarch, I386_NUM_GREGS + I386_NUM_FREGS + + I386_NUM_XREGS); +} + void _initialize_i386nbsd_tdep (void) { add_core_fns (&i386nbsd_core_fns); add_core_fns (&i386nbsd_elfcore_fns); + + gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_NETBSD_AOUT, + i386nbsd_init_abi); + gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_NETBSD_ELF, + i386nbsdelf_init_abi); } |