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/* Native-dependent code for OpenBSD/amd64.
Copyright (C) 2003-2020 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
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, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "gdbcore.h"
#include "regcache.h"
#include "target.h"
#include "amd64-tdep.h"
#include "amd64-bsd-nat.h"
#include "amd64-nat.h"
#include "obsd-nat.h"
/* Mapping between the general-purpose registers in OpenBSD/amd64
`struct reg' format and GDB's register cache layout for
OpenBSD/i386.
Note that most (if not all) OpenBSD/amd64 registers are 64-bit,
while the OpenBSD/i386 registers are all 32-bit, but since we're
little-endian we get away with that. */
/* From <machine/reg.h>. */
static int amd64obsd32_r_reg_offset[] =
{
14 * 8, /* %eax */
3 * 8, /* %ecx */
2 * 8, /* %edx */
13 * 8, /* %ebx */
15 * 8, /* %esp */
12 * 8, /* %ebp */
1 * 8, /* %esi */
0 * 8, /* %edi */
16 * 8, /* %eip */
17 * 8, /* %eflags */
18 * 8, /* %cs */
19 * 8, /* %ss */
20 * 8, /* %ds */
21 * 8, /* %es */
22 * 8, /* %fs */
23 * 8 /* %gs */
};
/* Support for debugging kernel virtual memory images. */
#include <sys/types.h>
#include <machine/frame.h>
#include <machine/pcb.h>
#include "bsd-kvm.h"
static int
amd64obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
{
struct switchframe sf;
int regnum;
/* The following is true for OpenBSD 3.5:
The pcb contains the stack pointer at the point of the context
switch in cpu_switch(). At that point we have a stack frame as
described by `struct switchframe', which for OpenBSD 3.5 has the
following layout:
interrupt level
%r15
%r14
%r13
%r12
%rbp
%rbx
return address
Together with %rsp in the pcb, this accounts for all callee-saved
registers specified by the psABI. From this information we
reconstruct the register state as it would look when we just
returned from cpu_switch().
For core dumps the pcb is saved by savectx(). In that case the
stack frame only contains the return address, and there is no way
to recover the other registers. */
/* The stack pointer shouldn't be zero. */
if (pcb->pcb_rsp == 0)
return 0;
/* Read the stack frame, and check its validity. */
read_memory (pcb->pcb_rsp, (gdb_byte *) &sf, sizeof sf);
if (sf.sf_rbp == pcb->pcb_rbp)
{
/* Yes, we have a frame that matches cpu_switch(). */
pcb->pcb_rsp += sizeof (struct switchframe);
regcache->raw_supply (12, &sf.sf_r12);
regcache->raw_supply (13, &sf.sf_r13);
regcache->raw_supply (14, &sf.sf_r14);
regcache->raw_supply (15, &sf.sf_r15);
regcache->raw_supply (AMD64_RBX_REGNUM, &sf.sf_rbx);
regcache->raw_supply (AMD64_RIP_REGNUM, &sf.sf_rip);
}
else
{
/* No, the pcb must have been last updated by savectx(). */
pcb->pcb_rsp += 8;
regcache->raw_supply (AMD64_RIP_REGNUM, &sf);
}
regcache->raw_supply (AMD64_RSP_REGNUM, &pcb->pcb_rsp);
regcache->raw_supply (AMD64_RBP_REGNUM, &pcb->pcb_rbp);
return 1;
}
static amd64_bsd_nat_target<obsd_nat_target> the_amd64_obsd_nat_target;
void
_initialize_amd64obsd_nat (void)
{
amd64_native_gregset32_reg_offset = amd64obsd32_r_reg_offset;
amd64_native_gregset32_num_regs = ARRAY_SIZE (amd64obsd32_r_reg_offset);
amd64_native_gregset64_reg_offset = amd64obsd_r_reg_offset;
add_inf_child_target (&the_amd64_obsd_nat_target);
/* Support debugging kernel virtual memory images. */
bsd_kvm_add_target (amd64obsd_supply_pcb);
}
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