binutils-gdb/gdb/amd64-fbsd-nat.c
John Baldwin a49ce729c8 Add an x86_fbsd_nat_target mixin class for FreeBSD x86 native targets.
This class implements debug register support common between the i386
and amd64 native targets.

While here, remove #ifdef's for HAVE_PT_GETDBREGS in FreeBSD-specific
code.  The ptrace request has been present on FreeBSD x86
architectures since 4.0 (released in March 2000).  The last FreeBSD
release without this support is 3.5 released in June 2000.
2022-03-22 12:05:43 -07:00

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/* Native-dependent code for FreeBSD/amd64.
Copyright (C) 2003-2022 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 "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 "amd64-tdep.h"
#include "amd64-fbsd-tdep.h"
#include "amd64-nat.h"
#include "x86-nat.h"
#include "gdbsupport/x86-xstate.h"
#include "x86-fbsd-nat.h"
class amd64_fbsd_nat_target final : public x86_fbsd_nat_target
{
public:
void fetch_registers (struct regcache *, int) override;
void store_registers (struct regcache *, int) override;
const struct target_desc *read_description () override;
};
static amd64_fbsd_nat_target the_amd64_fbsd_nat_target;
#ifdef PT_GETXSTATE_INFO
static size_t xsave_len;
#endif
/* This is a layout of the amd64 'struct reg' but with i386
registers. */
static const struct regcache_map_entry amd64_fbsd32_gregmap[] =
{
{ 8, REGCACHE_MAP_SKIP, 8 },
{ 1, I386_EDI_REGNUM, 8 },
{ 1, I386_ESI_REGNUM, 8 },
{ 1, I386_EBP_REGNUM, 8 },
{ 1, I386_EBX_REGNUM, 8 },
{ 1, I386_EDX_REGNUM, 8 },
{ 1, I386_ECX_REGNUM, 8 },
{ 1, I386_EAX_REGNUM, 8 },
{ 1, REGCACHE_MAP_SKIP, 4 }, /* trapno */
{ 1, I386_FS_REGNUM, 2 },
{ 1, I386_GS_REGNUM, 2 },
{ 1, REGCACHE_MAP_SKIP, 4 }, /* err */
{ 1, I386_ES_REGNUM, 2 },
{ 1, I386_DS_REGNUM, 2 },
{ 1, I386_EIP_REGNUM, 8 },
{ 1, I386_CS_REGNUM, 8 },
{ 1, I386_EFLAGS_REGNUM, 8 },
{ 1, I386_ESP_REGNUM, 0 },
{ 1, I386_SS_REGNUM, 8 },
{ 0 }
};
static const struct regset amd64_fbsd32_gregset =
{
amd64_fbsd32_gregmap, regcache_supply_regset, regcache_collect_regset
};
/* Return the regset to use for 'struct reg' for the GDBARCH. */
static const struct regset *
find_gregset (struct gdbarch *gdbarch)
{
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
return &amd64_fbsd32_gregset;
else
return &amd64_fbsd_gregset;
}
/* Fetch register REGNUM from the inferior. If REGNUM is -1, do this
for all registers. */
void
amd64_fbsd_nat_target::fetch_registers (struct regcache *regcache, int regnum)
{
struct gdbarch *gdbarch = regcache->arch ();
#if defined(PT_GETFSBASE) || defined(PT_GETGSBASE)
const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
#endif
pid_t pid = get_ptrace_pid (regcache->ptid ());
const struct regset *gregset = find_gregset (gdbarch);
if (fetch_register_set<struct reg> (regcache, regnum, PT_GETREGS, gregset))
{
if (regnum != -1)
return;
}
#ifdef PT_GETFSBASE
if (regnum == -1 || regnum == tdep->fsbase_regnum)
{
register_t base;
if (ptrace (PT_GETFSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
perror_with_name (_("Couldn't get segment register fs_base"));
regcache->raw_supply (tdep->fsbase_regnum, &base);
if (regnum != -1)
return;
}
#endif
#ifdef PT_GETGSBASE
if (regnum == -1 || regnum == tdep->fsbase_regnum + 1)
{
register_t base;
if (ptrace (PT_GETGSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
perror_with_name (_("Couldn't get segment register gs_base"));
regcache->raw_supply (tdep->fsbase_regnum + 1, &base);
if (regnum != -1)
return;
}
#endif
/* There is no amd64_fxsave_supplies or amd64_xsave_supplies.
Instead, the earlier register sets return early if the request
was for a specific register that was already satisified to avoid
fetching the FPU/XSAVE state unnecessarily. */
#ifdef PT_GETXSTATE_INFO
if (xsave_len != 0)
{
void *xstateregs = alloca (xsave_len);
if (ptrace (PT_GETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
perror_with_name (_("Couldn't get extended state status"));
amd64_supply_xsave (regcache, regnum, xstateregs);
return;
}
#endif
struct fpreg fpregs;
if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
perror_with_name (_("Couldn't get floating point status"));
amd64_supply_fxsave (regcache, regnum, &fpregs);
}
/* Store register REGNUM back into the inferior. If REGNUM is -1, do
this for all registers. */
void
amd64_fbsd_nat_target::store_registers (struct regcache *regcache, int regnum)
{
struct gdbarch *gdbarch = regcache->arch ();
#if defined(PT_GETFSBASE) || defined(PT_GETGSBASE)
const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
#endif
pid_t pid = get_ptrace_pid (regcache->ptid ());
const struct regset *gregset = find_gregset (gdbarch);
if (store_register_set<struct reg> (regcache, regnum, PT_GETREGS, PT_SETREGS,
gregset))
{
if (regnum != -1)
return;
}
#ifdef PT_SETFSBASE
if (regnum == -1 || regnum == tdep->fsbase_regnum)
{
register_t base;
/* Clear the full base value to support 32-bit targets. */
base = 0;
regcache->raw_collect (tdep->fsbase_regnum, &base);
if (ptrace (PT_SETFSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
perror_with_name (_("Couldn't write segment register fs_base"));
if (regnum != -1)
return;
}
#endif
#ifdef PT_SETGSBASE
if (regnum == -1 || regnum == tdep->fsbase_regnum + 1)
{
register_t base;
/* Clear the full base value to support 32-bit targets. */
base = 0;
regcache->raw_collect (tdep->fsbase_regnum + 1, &base);
if (ptrace (PT_SETGSBASE, pid, (PTRACE_TYPE_ARG3) &base, 0) == -1)
perror_with_name (_("Couldn't write segment register gs_base"));
if (regnum != -1)
return;
}
#endif
/* There is no amd64_fxsave_supplies or amd64_xsave_supplies.
Instead, the earlier register sets return early if the request
was for a specific register that was already satisified to avoid
fetching the FPU/XSAVE state unnecessarily. */
#ifdef PT_GETXSTATE_INFO
if (xsave_len != 0)
{
void *xstateregs = alloca (xsave_len);
if (ptrace (PT_GETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
perror_with_name (_("Couldn't get extended state status"));
amd64_collect_xsave (regcache, regnum, xstateregs, 0);
if (ptrace (PT_SETXSTATE, pid, (PTRACE_TYPE_ARG3) xstateregs,
xsave_len) == -1)
perror_with_name (_("Couldn't write extended state status"));
return;
}
#endif
struct fpreg fpregs;
if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
perror_with_name (_("Couldn't get floating point status"));
amd64_collect_fxsave (regcache, regnum, &fpregs);
if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
perror_with_name (_("Couldn't write floating point status"));
}
/* 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 (AMD64_RIP_REGNUM, &pcb->pcb_rip);
regcache->raw_supply (AMD64_RBX_REGNUM, &pcb->pcb_rbx);
regcache->raw_supply (AMD64_RSP_REGNUM, &pcb->pcb_rsp);
regcache->raw_supply (AMD64_RBP_REGNUM, &pcb->pcb_rbp);
regcache->raw_supply (12, &pcb->pcb_r12);
regcache->raw_supply (13, &pcb->pcb_r13);
regcache->raw_supply (14, &pcb->pcb_r14);
regcache->raw_supply (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 (AMD64_DS_REGNUM, &pcb->pcb_ds);
regcache->raw_supply (AMD64_ES_REGNUM, &pcb->pcb_es);
regcache->raw_supply (AMD64_FS_REGNUM, &pcb->pcb_fs);
regcache->raw_supply (AMD64_GS_REGNUM, &pcb->pcb_gs);
#endif
return 1;
}
/* Implement the read_description method. */
const struct target_desc *
amd64_fbsd_nat_target::read_description ()
{
#ifdef PT_GETXSTATE_INFO
static int xsave_probed;
static uint64_t xcr0;
#endif
struct reg regs;
int is64;
if (ptrace (PT_GETREGS, inferior_ptid.pid (),
(PTRACE_TYPE_ARG3) &regs, 0) == -1)
perror_with_name (_("Couldn't get registers"));
is64 = (regs.r_cs == GSEL (GUCODE_SEL, SEL_UPL));
#ifdef PT_GETXSTATE_INFO
if (!xsave_probed)
{
struct ptrace_xstate_info info;
if (ptrace (PT_GETXSTATE_INFO, inferior_ptid.pid (),
(PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0)
{
xsave_len = info.xsave_len;
xcr0 = info.xsave_mask;
}
xsave_probed = 1;
}
if (xsave_len != 0)
{
if (is64)
return amd64_target_description (xcr0, true);
else
return i386_target_description (xcr0, true);
}
#endif
if (is64)
return amd64_target_description (X86_XSTATE_SSE_MASK, true);
else
return i386_target_description (X86_XSTATE_SSE_MASK, true);
}
void _initialize_amd64fbsd_nat ();
void
_initialize_amd64fbsd_nat ()
{
add_inf_child_target (&the_amd64_fbsd_nat_target);
/* Support debugging kernel virtual memory images. */
bsd_kvm_add_target (amd64fbsd_supply_pcb);
}