/* Target-dependent code for NetBSD/i386, for GDB.
- Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002
+ Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, 2003
Free Software Foundation, Inc.
This file is part of GDB.
#include "gdbtypes.h"
#include "gdbcore.h"
#include "regcache.h"
+#include "arch-utils.h"
+#include "osabi.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[] =
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);
+ /* FIXME: kettenis/20020906: We should probably provide
+ NetBSD-specific versions of these functions if we want to
+ recognize signal trampolines that live on the stack. */
+ set_gdbarch_sigtramp_start (gdbarch, NULL);
+ set_gdbarch_sigtramp_end (gdbarch, NULL);
+
+ /* 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, 0, GDB_OSABI_NETBSD_AOUT,
+ i386nbsd_init_abi);
+ gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_ELF,
+ i386nbsdelf_init_abi);
}
projects / binutils-gdb.git / blobdiff