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/* Native-dependent code for FreeBSD/amd64.
Copyright (C) 2003-2016 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 3 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
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, see <>. */
#include "defs.h"
#include "inferior.h"
#include "regcache.h"
#include "target.h"
#include <signal.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include <machine/reg.h>
#include "fbsd-nat.h"
#include "amd64-tdep.h"
#include "amd64-nat.h"
#include "amd64bsd-nat.h"
#include "x86-nat.h"
/* Offset in `struct reg' where MEMBER is stored. */
#define REG_OFFSET(member) offsetof (struct reg, member)
/* At amd64fbsd64_r_reg_offset[REGNUM] you'll find the offset in
`struct reg' location where the GDB register REGNUM is stored.
Unsupported registers are marked with `-1'. */
static int amd64fbsd64_r_reg_offset[] =
REG_OFFSET (r_rax),
REG_OFFSET (r_rbx),
REG_OFFSET (r_rcx),
REG_OFFSET (r_rdx),
REG_OFFSET (r_rsi),
REG_OFFSET (r_rdi),
REG_OFFSET (r_rbp),
REG_OFFSET (r_rsp),
REG_OFFSET (r_r8),
REG_OFFSET (r_r9),
REG_OFFSET (r_r10),
REG_OFFSET (r_r11),
REG_OFFSET (r_r12),
REG_OFFSET (r_r13),
REG_OFFSET (r_r14),
REG_OFFSET (r_r15),
REG_OFFSET (r_rip),
REG_OFFSET (r_rflags),
REG_OFFSET (r_cs),
REG_OFFSET (r_ss),
/* Mapping between the general-purpose registers in FreeBSD/amd64
`struct reg' format and GDB's register cache layout for
Note that most FreeBSD/amd64 registers are 64-bit, while the
FreeBSD/i386 registers are all 32-bit, but since we're
little-endian we get away with that. */
/* From <machine/reg.h>. */
static int amd64fbsd32_r_reg_offset[I386_NUM_GREGS] =
14 * 8, 13 * 8, /* %eax, %ecx */
12 * 8, 11 * 8, /* %edx, %ebx */
20 * 8, 10 * 8, /* %esp, %ebp */
9 * 8, 8 * 8, /* %esi, %edi */
17 * 8, 19 * 8, /* %eip, %eflags */
18 * 8, 21 * 8, /* %cs, %ss */
-1, -1, -1, -1 /* %ds, %es, %fs, %gs */
/* Support for debugging kernel virtual memory images. */
#include <machine/pcb.h>
#include <osreldate.h>
#include "bsd-kvm.h"
static int
amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
/* The following is true for FreeBSD 5.2:
The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15,
%ds, %es, %fs and %gs. This accounts for all callee-saved
registers specified by the psABI and then some. Here %esp
contains the stack pointer at the point just after the call to
cpu_switch(). From this information we reconstruct the register
state as it would like when we just returned from cpu_switch(). */
/* The stack pointer shouldn't be zero. */
if (pcb->pcb_rsp == 0)
return 0;
pcb->pcb_rsp += 8;
regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &pcb->pcb_rip);
regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &pcb->pcb_rbx);
regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp);
regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp);
regcache_raw_supply (regcache, 12, &pcb->pcb_r12);
regcache_raw_supply (regcache, 13, &pcb->pcb_r13);
regcache_raw_supply (regcache, 14, &pcb->pcb_r14);
regcache_raw_supply (regcache, 15, &pcb->pcb_r15);
#if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075)
/* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only
up until __FreeBSD_version 800074: The removal of these fields
occurred on 2009-04-01 while the __FreeBSD_version number was
bumped to 800075 on 2009-04-06. So 800075 is the closest version
number where we should not try to access these fields. */
regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds);
regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es);
regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs);
regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs);
return 1;
static void (*super_mourn_inferior) (struct target_ops *ops);
static void
amd64fbsd_mourn_inferior (struct target_ops *ops)
x86_cleanup_dregs ();
super_mourn_inferior (ops);
/* Implement the to_read_description method. */
static const struct target_desc *
amd64fbsd_read_description (struct target_ops *ops)
static int xsave_probed;
static uint64_t xcr0;
struct reg regs;
int is64;
if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
(PTRACE_TYPE_ARG3) &regs, 0) == -1)
perror_with_name (_("Couldn't get registers"));
is64 = (regs.r_cs == GSEL (GUCODE_SEL, SEL_UPL));
if (!xsave_probed)
struct ptrace_xstate_info info;
if (ptrace (PT_GETXSTATE_INFO, ptid_get_pid (inferior_ptid),
(PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0)
amd64bsd_xsave_len = info.xsave_len;
xcr0 = info.xsave_mask;
xsave_probed = 1;
if (amd64bsd_xsave_len != 0)
if (is64)
return amd64_target_description (xcr0);
return i386_target_description (xcr0);
if (is64)
return tdesc_amd64;
return tdesc_i386;
/* Provide a prototype to silence -Wmissing-prototypes. */
void _initialize_amd64fbsd_nat (void);
_initialize_amd64fbsd_nat (void)
struct target_ops *t;
int offset;
amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
/* Add some extra features to the common *BSD/i386 target. */
t = amd64bsd_target ();
x86_use_watchpoints (t);
x86_dr_low.set_control = amd64bsd_dr_set_control;
x86_dr_low.set_addr = amd64bsd_dr_set_addr;
x86_dr_low.get_addr = amd64bsd_dr_get_addr;
x86_dr_low.get_status = amd64bsd_dr_get_status;
x86_dr_low.get_control = amd64bsd_dr_get_control;
x86_set_debug_register_length (8);
#endif /* HAVE_PT_GETDBREGS */
super_mourn_inferior = t->to_mourn_inferior;
t->to_mourn_inferior = amd64fbsd_mourn_inferior;
t->to_read_description = amd64fbsd_read_description;
fbsd_nat_add_target (t);
/* Support debugging kernel virtual memory images. */
bsd_kvm_add_target (amd64fbsd_supply_pcb);
/* To support the recognition of signal handlers, i386bsd-tdep.c
hardcodes some constants. Inclusion of this file means that we
are compiling a native debugger, which means that we can use the
system header files and sysctl(3) to get at the relevant
information. */
#define SC_REG_OFFSET amd64fbsd_sc_reg_offset
/* We only check the program counter, stack pointer and frame
pointer since these members of `struct sigcontext' are essential
for providing backtraces. */
/* Override the default value for the offset of the program counter
in the sigcontext structure. */
offset = offsetof (struct sigcontext, sc_rip);
if (SC_RIP_OFFSET != offset)
warning (_("\
offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
Please report this to <>."),
offset, SC_RIP_OFFSET);
SC_RIP_OFFSET = offset;
/* Likewise for the stack pointer. */
offset = offsetof (struct sigcontext, sc_rsp);
if (SC_RSP_OFFSET != offset)
warning (_("\
offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
Please report this to <>."),
offset, SC_RSP_OFFSET);
SC_RSP_OFFSET = offset;
/* And the frame pointer. */
offset = offsetof (struct sigcontext, sc_rbp);
if (SC_RBP_OFFSET != offset)
warning (_("\
offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
Please report this to <>."),
offset, SC_RBP_OFFSET);
SC_RBP_OFFSET = offset;
/* Normally signal frames are detected via amd64fbsd_sigtramp_p.
However, FreeBSD 9.2 through 10.1 do not include the page holding
the signal code in core dumps. These releases do provide a
kern.proc.sigtramp.<pid> sysctl that returns the location of the
signal trampoline for a running process. We fetch the location
of the current (gdb) process and use this to identify signal
frames in core dumps from these releases. Note that this only
works for core dumps of 64-bit (FreeBSD/amd64) processes and does
not handle core dumps of 32-bit (FreeBSD/i386) processes. */
int mib[4];
struct kinfo_sigtramp kst;
size_t len;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[3] = getpid ();
len = sizeof (kst);
if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
amd64fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start;
amd64fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end;