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266 lines
7.5 KiB
C
266 lines
7.5 KiB
C
/* Target-dependent code for OpenBSD/i386.
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Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002,
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2003, 2004
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Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "arch-utils.h"
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#include "frame.h"
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#include "gdbcore.h"
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#include "regcache.h"
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#include "regset.h"
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#include "symtab.h"
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#include "objfiles.h"
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#include "osabi.h"
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#include "target.h"
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#include "gdb_assert.h"
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#include "gdb_string.h"
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#include "i386-tdep.h"
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#include "i387-tdep.h"
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#include "solib-svr4.h"
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/* Support for signal handlers. */
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/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
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in virtual memory. The randomness makes it somewhat tricky to
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detect it, but fortunately we can rely on the fact that the start
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of the sigtramp routine is page-aligned. By the way, the mapping
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is read-only, so you cannot place a breakpoint in the signal
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trampoline. */
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/* Default page size. */
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static const int i386obsd_page_size = 4096;
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/* Return whether the frame preceding NEXT_FRAME corresponds to an
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OpenBSD sigtramp routine. */
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static int
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i386obsd_sigtramp_p (struct frame_info *next_frame)
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{
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CORE_ADDR pc = frame_pc_unwind (next_frame);
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CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1));
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const char sigreturn[] =
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{
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0xb8,
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0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */
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0xcd, 0x80 /* int $0x80 */
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};
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size_t buflen = sizeof sigreturn;
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char *name, *buf;
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/* If the function has a valid symbol name, it isn't a
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trampoline. */
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find_pc_partial_function (pc, &name, NULL, NULL);
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if (name != NULL)
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return 0;
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/* If the function lives in a valid section (even without a starting
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point) it isn't a trampoline. */
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if (find_pc_section (pc) != NULL)
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return 0;
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/* Allocate buffer. */
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buf = alloca (buflen);
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/* If we can't read the instructions at START_PC, return zero. */
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if (!safe_frame_unwind_memory (next_frame, start_pc + 0x0a, buf, buflen))
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return 0;
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/* Check for sigreturn(2). */
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if (memcmp (buf, sigreturn, buflen) == 0)
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return 1;
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/* If we can't read the instructions at START_PC, return zero. */
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if (!safe_frame_unwind_memory (next_frame, start_pc + 0x14, buf, buflen))
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return 0;
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/* Check for sigreturn(2) (again). */
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if (memcmp (buf, sigreturn, buflen) == 0)
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return 1;
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return 0;
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}
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/* Mapping between the general-purpose registers in `struct reg'
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format and GDB's register cache layout. */
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/* From <machine/reg.h>. */
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static int i386obsd_r_reg_offset[] =
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{
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0 * 4, /* %eax */
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1 * 4, /* %ecx */
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2 * 4, /* %edx */
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3 * 4, /* %ebx */
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4 * 4, /* %esp */
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5 * 4, /* %ebp */
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6 * 4, /* %esi */
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7 * 4, /* %edi */
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8 * 4, /* %eip */
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9 * 4, /* %eflags */
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10 * 4, /* %cs */
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11 * 4, /* %ss */
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12 * 4, /* %ds */
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13 * 4, /* %es */
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14 * 4, /* %fs */
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15 * 4 /* %gs */
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};
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static void
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i386obsd_aout_supply_regset (const struct regset *regset,
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struct regcache *regcache, int regnum,
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const void *regs, size_t len)
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{
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const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch);
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gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE);
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i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
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i387_supply_fsave (regcache, regnum, (char *) regs + tdep->sizeof_gregset);
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}
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static const struct regset *
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i386obsd_aout_regset_from_core_section (struct gdbarch *gdbarch,
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const char *sect_name,
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size_t sect_size)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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/* OpenBSD a.out core dumps don't use seperate register sets for the
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general-purpose and floating-point registers. */
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if (strcmp (sect_name, ".reg") == 0
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&& sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE)
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{
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if (tdep->gregset == NULL)
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tdep->gregset =
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regset_alloc (gdbarch, i386obsd_aout_supply_regset, NULL);
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return tdep->gregset;
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}
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return NULL;
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}
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/* Sigtramp routine location for OpenBSD 3.1 and earlier releases. */
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CORE_ADDR i386obsd_sigtramp_start_addr = 0xbfbfdf20;
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CORE_ADDR i386obsd_sigtramp_end_addr = 0xbfbfdff0;
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/* From <machine/signal.h>. */
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int i386obsd_sc_reg_offset[I386_NUM_GREGS] =
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{
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10 * 4, /* %eax */
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9 * 4, /* %ecx */
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8 * 4, /* %edx */
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7 * 4, /* %ebx */
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14 * 4, /* %esp */
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6 * 4, /* %ebp */
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5 * 4, /* %esi */
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4 * 4, /* %edi */
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11 * 4, /* %eip */
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13 * 4, /* %eflags */
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12 * 4, /* %cs */
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15 * 4, /* %ss */
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3 * 4, /* %ds */
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2 * 4, /* %es */
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1 * 4, /* %fs */
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0 * 4 /* %gs */
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};
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static void
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i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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/* Obviously OpenBSD is BSD-based. */
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i386bsd_init_abi (info, gdbarch);
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/* OpenBSD has a different `struct reg'. */
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tdep->gregset_reg_offset = i386obsd_r_reg_offset;
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tdep->gregset_num_regs = ARRAY_SIZE (i386obsd_r_reg_offset);
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tdep->sizeof_gregset = 16 * 4;
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/* OpenBSD uses -freg-struct-return by default. */
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tdep->struct_return = reg_struct_return;
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/* OpenBSD uses a different memory layout. */
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tdep->sigtramp_start = i386obsd_sigtramp_start_addr;
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tdep->sigtramp_end = i386obsd_sigtramp_end_addr;
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tdep->sigtramp_p = i386obsd_sigtramp_p;
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/* OpenBSD has a `struct sigcontext' that's different from the
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original 4.3 BSD. */
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tdep->sc_reg_offset = i386obsd_sc_reg_offset;
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tdep->sc_num_regs = ARRAY_SIZE (i386obsd_sc_reg_offset);
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}
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/* OpenBSD a.out. */
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static void
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i386obsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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i386obsd_init_abi (info, gdbarch);
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/* OpenBSD a.out has a single register set. */
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set_gdbarch_regset_from_core_section
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(gdbarch, i386obsd_aout_regset_from_core_section);
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}
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/* OpenBSD ELF. */
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static void
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i386obsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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/* It's still OpenBSD. */
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i386obsd_init_abi (info, gdbarch);
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/* But ELF-based. */
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i386_elf_init_abi (info, gdbarch);
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/* OpenBSD ELF uses SVR4-style shared libraries. */
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set_gdbarch_in_solib_call_trampoline
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(gdbarch, generic_in_solib_call_trampoline);
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set_solib_svr4_fetch_link_map_offsets
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(gdbarch, svr4_ilp32_fetch_link_map_offsets);
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}
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/* Provide a prototype to silence -Wmissing-prototypes. */
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void _initialize_i386obsd_tdep (void);
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void
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_initialize_i386obsd_tdep (void)
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{
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/* FIXME: kettenis/20021020: Since OpenBSD/i386 binaries are
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indistingushable from NetBSD/i386 a.out binaries, building a GDB
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that should support both these targets will probably not work as
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expected. */
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#define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT
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gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_AOUT,
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i386obsd_aout_init_abi);
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gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_ELF,
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i386obsd_elf_init_abi);
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}
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