cf424aef0a
- Use signal frame sniffers that look for the signal trampoline instruction sequence to detect most signal frames. - FreeBSD kernels between 9.2 and 10.1 inclusive do not include the signal trampoline code in process core dumps. To detect signal frames for core dumps under these kernels, use the kern.proc.sigtramp.<pid> sysctl to fetch the location of the signal trampoline in the gdb process and assume that PC values within this location are signal frames. This depends on that location being identical for all binaries. gdb/ChangeLog: 2015-02-25 John Baldwin <jhb@FreeBSD.org> * amd64fbsd-nat.c: Include sys/user.h. (_initialize_amd64fbsd_nat): Use the KERN_PROC_SIGTRAMP sysctl instead of KERN_PS_STRINGS to locate the signal trampoline. * i386fbsd-nat.c: Include sys/user.h. (_initialize_i386fbsd_nat): Use the KERN_PROC_SIGTRAMP sysctl instead of KERN_PS_STRINGS to locate the signal trampoline. * amd64fbsd-tdep.c (amd64fbsd_sigtramp_code): New. (amd64fbsd_sigtramp_p): New. (amd64fbsd_sigtramp_start_addr, amd64fbsd_sigtramp_end_addr): No longer set default values. (amd64fbsd_init_abi): Set "sigtramp_p" to "amd64fbsd_sigtramp_p". * i386fbsd-tdep.c (i386fbsd_sigtramp_start) (i386fbsd_sigtramp_middle, i386fbsd_sigtramp_end) (i386fbsd_freebsd4_sigtramp_start) (i386fbsd_freebsd4_sigtramp_middle) (i386fbsd_freebsd4_sigtramp_end, i386fbsd_osigtramp_start) (i386fbsd_osigtramp_middle, i386fbsd_osigtramp_end): New. (i386fbsd_sigtramp_p): New. (i386fbsd_sigtramp_start_addr, i386fbsd_sigtramp_end_addr): No longer set default values. (i386fbsd_init_abi): Set "sigtramp_p" to "i386fbsd_sigtramp_p".
386 lines
11 KiB
C
386 lines
11 KiB
C
/* Target-dependent code for FreeBSD/i386.
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Copyright (C) 2003-2015 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 3 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, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "arch-utils.h"
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#include "gdbcore.h"
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#include "osabi.h"
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#include "regcache.h"
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#include "i386-tdep.h"
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#include "i387-tdep.h"
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#include "bsd-uthread.h"
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#include "fbsd-tdep.h"
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#include "solib-svr4.h"
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/* Support for signal handlers. */
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/* Return whether THIS_FRAME corresponds to a FreeBSD sigtramp
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routine. */
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/* FreeBSD/i386 supports three different signal trampolines, one for
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versions before 4.0, a second for 4.x, and a third for 5.0 and
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later. To complicate matters, FreeBSD/i386 binaries running under
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an amd64 kernel use a different set of trampolines. These
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trampolines differ from the i386 kernel trampolines in that they
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omit a middle section that conditionally restores %gs. */
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static const gdb_byte i386fbsd_sigtramp_start[] =
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{
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0x8d, 0x44, 0x24, 0x20, /* lea SIGF_UC(%esp),%eax */
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0x50 /* pushl %eax */
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};
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static const gdb_byte i386fbsd_sigtramp_middle[] =
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{
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0xf7, 0x40, 0x54, 0x00, 0x00, 0x02, 0x00,
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/* testl $PSL_VM,UC_EFLAGS(%eax) */
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0x75, 0x03, /* jne +3 */
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0x8e, 0x68, 0x14 /* mov UC_GS(%eax),%gs */
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};
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static const gdb_byte i386fbsd_sigtramp_end[] =
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{
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0xb8, 0xa1, 0x01, 0x00, 0x00, /* movl $SYS_sigreturn,%eax */
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0x50, /* pushl %eax */
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0xcd, 0x80 /* int $0x80 */
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};
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static const gdb_byte i386fbsd_freebsd4_sigtramp_start[] =
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{
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0x8d, 0x44, 0x24, 0x14, /* lea SIGF_UC4(%esp),%eax */
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0x50 /* pushl %eax */
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};
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static const gdb_byte i386fbsd_freebsd4_sigtramp_middle[] =
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{
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0xf7, 0x40, 0x54, 0x00, 0x00, 0x02, 0x00,
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/* testl $PSL_VM,UC4_EFLAGS(%eax) */
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0x75, 0x03, /* jne +3 */
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0x8e, 0x68, 0x14 /* mov UC4_GS(%eax),%gs */
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};
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static const gdb_byte i386fbsd_freebsd4_sigtramp_end[] =
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{
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0xb8, 0x58, 0x01, 0x00, 0x00, /* movl $344,%eax */
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0x50, /* pushl %eax */
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0xcd, 0x80 /* int $0x80 */
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};
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static const gdb_byte i386fbsd_osigtramp_start[] =
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{
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0x8d, 0x44, 0x24, 0x14, /* lea SIGF_SC(%esp),%eax */
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0x50 /* pushl %eax */
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};
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static const gdb_byte i386fbsd_osigtramp_middle[] =
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{
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0xf7, 0x40, 0x18, 0x00, 0x00, 0x02, 0x00,
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/* testl $PSL_VM,SC_PS(%eax) */
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0x75, 0x03, /* jne +3 */
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0x8e, 0x68, 0x44 /* mov SC_GS(%eax),%gs */
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};
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static const gdb_byte i386fbsd_osigtramp_end[] =
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{
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0xb8, 0x67, 0x00, 0x00, 0x00, /* movl $103,%eax */
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0x50, /* pushl %eax */
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0xcd, 0x80 /* int $0x80 */
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};
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/* The three different trampolines are all the same size. */
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gdb_static_assert (sizeof i386fbsd_sigtramp_start ==
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sizeof i386fbsd_freebsd4_sigtramp_start);
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gdb_static_assert (sizeof i386fbsd_sigtramp_start ==
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sizeof i386fbsd_osigtramp_start);
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gdb_static_assert (sizeof i386fbsd_sigtramp_middle ==
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sizeof i386fbsd_freebsd4_sigtramp_middle);
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gdb_static_assert (sizeof i386fbsd_sigtramp_middle ==
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sizeof i386fbsd_osigtramp_middle);
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gdb_static_assert (sizeof i386fbsd_sigtramp_end ==
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sizeof i386fbsd_freebsd4_sigtramp_end);
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gdb_static_assert (sizeof i386fbsd_sigtramp_end ==
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sizeof i386fbsd_osigtramp_end);
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/* We assume that the middle is the largest chunk below. */
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gdb_static_assert (sizeof i386fbsd_sigtramp_middle >
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sizeof i386fbsd_sigtramp_start);
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gdb_static_assert (sizeof i386fbsd_sigtramp_middle >
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sizeof i386fbsd_sigtramp_end);
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static int
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i386fbsd_sigtramp_p (struct frame_info *this_frame)
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{
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CORE_ADDR pc = get_frame_pc (this_frame);
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gdb_byte buf[sizeof i386fbsd_sigtramp_middle];
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const gdb_byte *middle, *end;
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/* Look for a matching start. */
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if (!safe_frame_unwind_memory (this_frame, pc, buf,
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sizeof i386fbsd_sigtramp_start))
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return 0;
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if (memcmp (buf, i386fbsd_sigtramp_start, sizeof i386fbsd_sigtramp_start) ==
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0) {
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middle = i386fbsd_sigtramp_middle;
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end = i386fbsd_sigtramp_end;
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} else if (memcmp (buf, i386fbsd_freebsd4_sigtramp_start,
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sizeof i386fbsd_freebsd4_sigtramp_start) == 0) {
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middle = i386fbsd_freebsd4_sigtramp_middle;
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end = i386fbsd_freebsd4_sigtramp_end;
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} else if (memcmp (buf, i386fbsd_osigtramp_start,
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sizeof i386fbsd_osigtramp_start) == 0) {
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middle = i386fbsd_osigtramp_middle;
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end = i386fbsd_osigtramp_end;
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} else
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return 0;
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/* Since the end is shorter than the middle, check for a matching end
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next. */
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pc += sizeof i386fbsd_sigtramp_start;
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if (!safe_frame_unwind_memory (this_frame, pc, buf,
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sizeof i386fbsd_sigtramp_end))
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return 0;
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if (memcmp (buf, end, sizeof i386fbsd_sigtramp_end) == 0)
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return 1;
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/* If the end didn't match, check for a matching middle. */
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if (!safe_frame_unwind_memory (this_frame, pc, buf,
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sizeof i386fbsd_sigtramp_middle))
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return 0;
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if (memcmp (buf, middle, sizeof i386fbsd_sigtramp_middle) != 0)
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return 0;
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/* The middle matched, check for a matching end. */
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pc += sizeof i386fbsd_sigtramp_middle;
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if (!safe_frame_unwind_memory (this_frame, pc, buf,
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sizeof i386fbsd_sigtramp_end))
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return 0;
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if (memcmp (buf, end, sizeof i386fbsd_sigtramp_end) != 0)
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return 0;
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return 1;
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}
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/* FreeBSD 3.0-RELEASE or later. */
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/* From <machine/reg.h>. */
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static int i386fbsd_r_reg_offset[] =
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{
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9 * 4, 8 * 4, 7 * 4, 6 * 4, /* %eax, %ecx, %edx, %ebx */
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15 * 4, 4 * 4, /* %esp, %ebp */
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3 * 4, 2 * 4, /* %esi, %edi */
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12 * 4, 14 * 4, /* %eip, %eflags */
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13 * 4, 16 * 4, /* %cs, %ss */
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1 * 4, 0 * 4, -1, -1 /* %ds, %es, %fs, %gs */
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};
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/* Sigtramp routine location. */
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CORE_ADDR i386fbsd_sigtramp_start_addr;
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CORE_ADDR i386fbsd_sigtramp_end_addr;
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/* From <machine/signal.h>. */
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int i386fbsd_sc_reg_offset[] =
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{
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8 + 14 * 4, /* %eax */
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8 + 13 * 4, /* %ecx */
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8 + 12 * 4, /* %edx */
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8 + 11 * 4, /* %ebx */
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8 + 0 * 4, /* %esp */
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8 + 1 * 4, /* %ebp */
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8 + 10 * 4, /* %esi */
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8 + 9 * 4, /* %edi */
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8 + 3 * 4, /* %eip */
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8 + 4 * 4, /* %eflags */
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8 + 7 * 4, /* %cs */
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8 + 8 * 4, /* %ss */
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8 + 6 * 4, /* %ds */
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8 + 5 * 4, /* %es */
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8 + 15 * 4, /* %fs */
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8 + 16 * 4 /* %gs */
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};
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/* From /usr/src/lib/libc/i386/gen/_setjmp.S. */
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static int i386fbsd_jmp_buf_reg_offset[] =
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{
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-1, /* %eax */
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-1, /* %ecx */
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-1, /* %edx */
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1 * 4, /* %ebx */
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2 * 4, /* %esp */
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3 * 4, /* %ebp */
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4 * 4, /* %esi */
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5 * 4, /* %edi */
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0 * 4 /* %eip */
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};
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static void
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i386fbsd_supply_uthread (struct regcache *regcache,
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int regnum, CORE_ADDR addr)
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{
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gdb_byte buf[4];
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int i;
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gdb_assert (regnum >= -1);
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for (i = 0; i < ARRAY_SIZE (i386fbsd_jmp_buf_reg_offset); i++)
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{
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if (i386fbsd_jmp_buf_reg_offset[i] != -1
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&& (regnum == -1 || regnum == i))
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{
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read_memory (addr + i386fbsd_jmp_buf_reg_offset[i], buf, 4);
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regcache_raw_supply (regcache, i, buf);
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}
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}
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}
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static void
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i386fbsd_collect_uthread (const struct regcache *regcache,
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int regnum, CORE_ADDR addr)
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{
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gdb_byte buf[4];
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int i;
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gdb_assert (regnum >= -1);
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for (i = 0; i < ARRAY_SIZE (i386fbsd_jmp_buf_reg_offset); i++)
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{
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if (i386fbsd_jmp_buf_reg_offset[i] != -1
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&& (regnum == -1 || regnum == i))
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{
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regcache_raw_collect (regcache, i, buf);
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write_memory (addr + i386fbsd_jmp_buf_reg_offset[i], buf, 4);
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}
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}
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}
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static void
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i386fbsdaout_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 FreeBSD is BSD-based. */
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i386bsd_init_abi (info, gdbarch);
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/* FreeBSD has a different `struct reg', and reserves some space for
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its FPU emulator in `struct fpreg'. */
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tdep->gregset_reg_offset = i386fbsd_r_reg_offset;
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tdep->gregset_num_regs = ARRAY_SIZE (i386fbsd_r_reg_offset);
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tdep->sizeof_gregset = 18 * 4;
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tdep->sizeof_fpregset = 176;
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/* FreeBSD uses -freg-struct-return by default. */
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tdep->struct_return = reg_struct_return;
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tdep->sigtramp_p = i386fbsd_sigtramp_p;
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/* FreeBSD uses a different memory layout. */
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tdep->sigtramp_start = i386fbsd_sigtramp_start_addr;
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tdep->sigtramp_end = i386fbsd_sigtramp_end_addr;
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/* FreeBSD has a more complete `struct sigcontext'. */
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tdep->sc_reg_offset = i386fbsd_sc_reg_offset;
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tdep->sc_num_regs = ARRAY_SIZE (i386fbsd_sc_reg_offset);
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/* FreeBSD provides a user-level threads implementation. */
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bsd_uthread_set_supply_uthread (gdbarch, i386fbsd_supply_uthread);
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bsd_uthread_set_collect_uthread (gdbarch, i386fbsd_collect_uthread);
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}
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static void
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i386fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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/* It's almost identical to FreeBSD a.out. */
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i386fbsdaout_init_abi (info, gdbarch);
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/* Except that it uses ELF. */
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i386_elf_init_abi (info, gdbarch);
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/* FreeBSD ELF uses SVR4-style shared libraries. */
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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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/* FreeBSD 4.0-RELEASE or later. */
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/* From <machine/reg.h>. */
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static int i386fbsd4_r_reg_offset[] =
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{
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10 * 4, 9 * 4, 8 * 4, 7 * 4, /* %eax, %ecx, %edx, %ebx */
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16 * 4, 5 * 4, /* %esp, %ebp */
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4 * 4, 3 * 4, /* %esi, %edi */
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13 * 4, 15 * 4, /* %eip, %eflags */
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14 * 4, 17 * 4, /* %cs, %ss */
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2 * 4, 1 * 4, 0 * 4, 18 * 4 /* %ds, %es, %fs, %gs */
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};
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/* From <machine/signal.h>. */
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int i386fbsd4_sc_reg_offset[] =
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{
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20 + 11 * 4, /* %eax */
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20 + 10 * 4, /* %ecx */
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20 + 9 * 4, /* %edx */
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20 + 8 * 4, /* %ebx */
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20 + 17 * 4, /* %esp */
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20 + 6 * 4, /* %ebp */
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20 + 5 * 4, /* %esi */
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20 + 4 * 4, /* %edi */
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20 + 14 * 4, /* %eip */
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20 + 16 * 4, /* %eflags */
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20 + 15 * 4, /* %cs */
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20 + 18 * 4, /* %ss */
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20 + 3 * 4, /* %ds */
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20 + 2 * 4, /* %es */
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20 + 1 * 4, /* %fs */
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20 + 0 * 4 /* %gs */
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};
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static void
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i386fbsd4_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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/* Generic FreeBSD support. */
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fbsd_init_abi (info, gdbarch);
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/* Inherit stuff from older releases. We assume that FreeBSD
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4.0-RELEASE always uses ELF. */
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i386fbsd_init_abi (info, gdbarch);
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/* FreeBSD 4.0 introduced a new `struct reg'. */
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tdep->gregset_reg_offset = i386fbsd4_r_reg_offset;
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tdep->gregset_num_regs = ARRAY_SIZE (i386fbsd4_r_reg_offset);
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tdep->sizeof_gregset = 19 * 4;
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/* FreeBSD 4.0 introduced a new `struct sigcontext'. */
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tdep->sc_reg_offset = i386fbsd4_sc_reg_offset;
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tdep->sc_num_regs = ARRAY_SIZE (i386fbsd4_sc_reg_offset);
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}
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/* Provide a prototype to silence -Wmissing-prototypes. */
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void _initialize_i386fbsd_tdep (void);
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void
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_initialize_i386fbsd_tdep (void)
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{
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gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD_AOUT,
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i386fbsdaout_init_abi);
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gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD_ELF,
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i386fbsd4_init_abi);
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}
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