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Diffstat (limited to 'gdb/vaxobsd-tdep.c')
| -rw-r--r-- | gdb/vaxobsd-tdep.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/gdb/vaxobsd-tdep.c b/gdb/vaxobsd-tdep.c new file mode 100644 index 00000000000..41a609db9db --- /dev/null +++ b/gdb/vaxobsd-tdep.c @@ -0,0 +1,190 @@ +/* Target-dependent code for OpenBSD/vax. + + Copyright 2005 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include "defs.h" +#include "arch-utils.h" +#include "frame.h" +#include "frame-unwind.h" +#include "osabi.h" +#include "symtab.h" +#include "trad-frame.h" + +#include "vax-tdep.h" + +#include "gdb_string.h" + +/* Signal trampolines. */ + +/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page + in virtual memory. The randomness makes it somewhat tricky to + detect it, but fortunately we can rely on the fact that the start + of the sigtramp routine is page-aligned. We recognize the + trampoline by looking for the code that invokes the sigreturn + system call. The offset where we can find that code varies from + release to release. + + By the way, the mapping mentioned above is read-only, so you cannot + place a breakpoint in the signal trampoline. */ + +/* Default page size. */ +static const int vaxobsd_page_size = 4096; + +/* Offset for sigreturn(2). */ +static const int vaxobsd_sigreturn_offset = 0x11; + +/* Instruction sequence for sigreturn(2). VAX doesn't have + fixed-length instructions so we include the ensuing exit(2) to + reduce the chance of spurious matches. */ +static const gdb_byte vaxobsd_sigreturn[] = { + 0xbc, 0x8f, 0x67, 0x00, /* chmk $SYS_sigreturn */ + 0xbc, 0x01 /* chmk $SYS_exit */ +}; + +static int +vaxobsd_sigtramp_p (struct frame_info *next_frame) +{ + CORE_ADDR pc = frame_pc_unwind (next_frame); + CORE_ADDR start_pc = (pc & ~(vaxobsd_page_size - 1)); + CORE_ADDR sigreturn_addr = start_pc + vaxobsd_sigreturn_offset; + gdb_byte *buf; + char *name; + + find_pc_partial_function (pc, &name, NULL, NULL); + if (name) + return 0; + + buf = alloca(sizeof vaxobsd_sigreturn); + if (!safe_frame_unwind_memory (next_frame, sigreturn_addr, + buf, sizeof vaxobsd_sigreturn)) + return 0; + + if (memcmp(buf, vaxobsd_sigreturn, sizeof vaxobsd_sigreturn) == 0) + return 1; + + return 0; +} + +static struct trad_frame_cache * +vaxobsd_sigtramp_frame_cache (struct frame_info *next_frame, void **this_cache) +{ + struct trad_frame_cache *cache; + CORE_ADDR addr, base, func; + + if (*this_cache) + return *this_cache; + + cache = trad_frame_cache_zalloc (next_frame); + *this_cache = cache; + + func = frame_pc_unwind (next_frame); + func &= ~(vaxobsd_page_size - 1); + + base = frame_unwind_register_unsigned (next_frame, VAX_SP_REGNUM); + addr = get_frame_memory_unsigned (next_frame, base - 4, 4); + + trad_frame_set_reg_addr (cache, VAX_SP_REGNUM, addr + 8); + trad_frame_set_reg_addr (cache, VAX_FP_REGNUM, addr + 12); + trad_frame_set_reg_addr (cache, VAX_AP_REGNUM, addr + 16); + trad_frame_set_reg_addr (cache, VAX_PC_REGNUM, addr + 20); + trad_frame_set_reg_addr (cache, VAX_PS_REGNUM, addr + 24); + + /* Construct the frame ID using the function start. */ + trad_frame_set_id (cache, frame_id_build (base, func)); + + return cache; +} + +static void +vaxobsd_sigtramp_frame_this_id (struct frame_info *next_frame, + void **this_cache, struct frame_id *this_id) +{ + struct trad_frame_cache *cache = + vaxobsd_sigtramp_frame_cache (next_frame, this_cache); + + trad_frame_get_id (cache, this_id); +} + +static void +vaxobsd_sigtramp_frame_prev_register (struct frame_info *next_frame, + void **this_cache, int regnum, + int *optimizedp, enum lval_type *lvalp, + CORE_ADDR *addrp, int *realnump, + gdb_byte *valuep) +{ + struct trad_frame_cache *cache = + vaxobsd_sigtramp_frame_cache (next_frame, this_cache); + + trad_frame_get_register (cache, next_frame, regnum, + optimizedp, lvalp, addrp, realnump, valuep); +} + +static const struct frame_unwind vaxobsd_sigtramp_frame_unwind = { + SIGTRAMP_FRAME, + vaxobsd_sigtramp_frame_this_id, + vaxobsd_sigtramp_frame_prev_register +}; + +static const struct frame_unwind * +vaxobsd_sigtramp_frame_sniffer (struct frame_info *next_frame) +{ + if (vaxobsd_sigtramp_p (next_frame)) + return &vaxobsd_sigtramp_frame_unwind; + + return NULL; +} + + +/* OpenBSD a.out. */ + +static void +vaxobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) +{ + frame_unwind_append_sniffer (gdbarch, vaxobsd_sigtramp_frame_sniffer); +} + +/* FIXME: kettenis/20050821: Since OpenBSD/vax binaries are + indistingushable from NetBSD/vax a.out binaries, building a GDB + that should support both these targets will probably not work as + expected. */ +#define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT + +static enum gdb_osabi +vaxobsd_aout_osabi_sniffer (bfd *abfd) +{ + if (strcmp (bfd_get_target (abfd), "a.out-vax-netbsd") == 0) + return GDB_OSABI_OPENBSD_AOUT; + + return GDB_OSABI_UNKNOWN; +} + + +/* Provide a prototype to silence -Wmissing-prototypes. */ +void _initialize_vaxobsd_tdep (void); + +void +_initialize_vaxobsd_tdep (void) +{ + gdbarch_register_osabi_sniffer (bfd_arch_vax, bfd_target_aout_flavour, + vaxobsd_aout_osabi_sniffer); + + gdbarch_register_osabi (bfd_arch_vax, 0, GDB_OSABI_OPENBSD_AOUT, + vaxobsd_init_abi); +} |