blob: 38ff461a35b3955780e6ce49c69b0e05c4b27136 [file] [log] [blame]
/* Native-dependent code for GNU/Linux on MIPS processors.
Copyright (C) 2001-2020 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 "command.h"
#include "gdbcmd.h"
#include "inferior.h"
#include "mips-tdep.h"
#include "target.h"
#include "regcache.h"
#include "linux-nat-trad.h"
#include "mips-linux-tdep.h"
#include "target-descriptions.h"
#include "gdb_proc_service.h"
#include "gregset.h"
#include <sgidefs.h>
#include "nat/gdb_ptrace.h"
#include <asm/ptrace.h>
#include "inf-ptrace.h"
#include "nat/mips-linux-watch.h"
#ifndef PTRACE_GET_THREAD_AREA
#define PTRACE_GET_THREAD_AREA 25
#endif
class mips_linux_nat_target final : public linux_nat_trad_target
{
public:
/* Add our register access methods. */
void fetch_registers (struct regcache *, int) override;
void store_registers (struct regcache *, int) override;
void close () override;
int can_use_hw_breakpoint (enum bptype, int, int) override;
int remove_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
struct expression *) override;
int insert_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
struct expression *) override;
bool stopped_by_watchpoint () override;
bool stopped_data_address (CORE_ADDR *) override;
int region_ok_for_hw_watchpoint (CORE_ADDR, int) override;
const struct target_desc *read_description () override;
protected:
/* Override linux_nat_trad_target methods. */
CORE_ADDR register_u_offset (struct gdbarch *gdbarch,
int regno, int store_p) override;
/* Override linux_nat_target low methods. */
void low_new_thread (struct lwp_info *lp) override;
private:
/* Helpers. See definitions. */
void mips64_regsets_store_registers (struct regcache *regcache,
int regno);
void mips64_regsets_fetch_registers (struct regcache *regcache,
int regno);
};
static mips_linux_nat_target the_mips_linux_nat_target;
/* Assume that we have PTRACE_GETREGS et al. support. If we do not,
we'll clear this and use PTRACE_PEEKUSER instead. */
static int have_ptrace_regsets = 1;
/* Map gdb internal register number to ptrace ``address''.
These ``addresses'' are normally defined in <asm/ptrace.h>.
ptrace does not provide a way to read (or set) MIPS_PS_REGNUM,
and there's no point in reading or setting MIPS_ZERO_REGNUM.
We also can not set BADVADDR, CAUSE, or FCRIR via ptrace(). */
static CORE_ADDR
mips_linux_register_addr (struct gdbarch *gdbarch, int regno, int store)
{
CORE_ADDR regaddr;
if (regno < 0 || regno >= gdbarch_num_regs (gdbarch))
error (_("Bogon register number %d."), regno);
if (regno > MIPS_ZERO_REGNUM && regno < MIPS_ZERO_REGNUM + 32)
regaddr = regno;
else if ((regno >= mips_regnum (gdbarch)->fp0)
&& (regno < mips_regnum (gdbarch)->fp0 + 32))
regaddr = FPR_BASE + (regno - mips_regnum (gdbarch)->fp0);
else if (regno == mips_regnum (gdbarch)->pc)
regaddr = PC;
else if (regno == mips_regnum (gdbarch)->cause)
regaddr = store? (CORE_ADDR) -1 : CAUSE;
else if (regno == mips_regnum (gdbarch)->badvaddr)
regaddr = store? (CORE_ADDR) -1 : BADVADDR;
else if (regno == mips_regnum (gdbarch)->lo)
regaddr = MMLO;
else if (regno == mips_regnum (gdbarch)->hi)
regaddr = MMHI;
else if (regno == mips_regnum (gdbarch)->fp_control_status)
regaddr = FPC_CSR;
else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
regaddr = store? (CORE_ADDR) -1 : FPC_EIR;
else if (mips_regnum (gdbarch)->dspacc != -1
&& regno >= mips_regnum (gdbarch)->dspacc
&& regno < mips_regnum (gdbarch)->dspacc + 6)
regaddr = DSP_BASE + (regno - mips_regnum (gdbarch)->dspacc);
else if (regno == mips_regnum (gdbarch)->dspctl)
regaddr = DSP_CONTROL;
else if (mips_linux_restart_reg_p (gdbarch) && regno == MIPS_RESTART_REGNUM)
regaddr = 0;
else
regaddr = (CORE_ADDR) -1;
return regaddr;
}
static CORE_ADDR
mips64_linux_register_addr (struct gdbarch *gdbarch, int regno, int store)
{
CORE_ADDR regaddr;
if (regno < 0 || regno >= gdbarch_num_regs (gdbarch))
error (_("Bogon register number %d."), regno);
/* On n32 we can't access 64-bit registers via PTRACE_PEEKUSR
or PTRACE_POKEUSR. */
if (register_size (gdbarch, regno) > sizeof (PTRACE_TYPE_RET))
return (CORE_ADDR) -1;
if (regno > MIPS_ZERO_REGNUM && regno < MIPS_ZERO_REGNUM + 32)
regaddr = regno;
else if ((regno >= mips_regnum (gdbarch)->fp0)
&& (regno < mips_regnum (gdbarch)->fp0 + 32))
regaddr = MIPS64_FPR_BASE + (regno - gdbarch_fp0_regnum (gdbarch));
else if (regno == mips_regnum (gdbarch)->pc)
regaddr = MIPS64_PC;
else if (regno == mips_regnum (gdbarch)->cause)
regaddr = store? (CORE_ADDR) -1 : MIPS64_CAUSE;
else if (regno == mips_regnum (gdbarch)->badvaddr)
regaddr = store? (CORE_ADDR) -1 : MIPS64_BADVADDR;
else if (regno == mips_regnum (gdbarch)->lo)
regaddr = MIPS64_MMLO;
else if (regno == mips_regnum (gdbarch)->hi)
regaddr = MIPS64_MMHI;
else if (regno == mips_regnum (gdbarch)->fp_control_status)
regaddr = MIPS64_FPC_CSR;
else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
regaddr = store? (CORE_ADDR) -1 : MIPS64_FPC_EIR;
else if (mips_regnum (gdbarch)->dspacc != -1
&& regno >= mips_regnum (gdbarch)->dspacc
&& regno < mips_regnum (gdbarch)->dspacc + 6)
regaddr = DSP_BASE + (regno - mips_regnum (gdbarch)->dspacc);
else if (regno == mips_regnum (gdbarch)->dspctl)
regaddr = DSP_CONTROL;
else if (mips_linux_restart_reg_p (gdbarch) && regno == MIPS_RESTART_REGNUM)
regaddr = 0;
else
regaddr = (CORE_ADDR) -1;
return regaddr;
}
/* Fetch the thread-local storage pointer for libthread_db. */
ps_err_e
ps_get_thread_area (struct ps_prochandle *ph,
lwpid_t lwpid, int idx, void **base)
{
if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
return PS_ERR;
/* IDX is the bias from the thread pointer to the beginning of the
thread descriptor. It has to be subtracted due to implementation
quirks in libthread_db. */
*base = (void *) ((char *)*base - idx);
return PS_OK;
}
/* Wrapper functions. These are only used by libthread_db. */
void
supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
{
if (mips_isa_regsize (regcache->arch ()) == 4)
mips_supply_gregset (regcache, (const mips_elf_gregset_t *) gregsetp);
else
mips64_supply_gregset (regcache, (const mips64_elf_gregset_t *) gregsetp);
}
void
fill_gregset (const struct regcache *regcache,
gdb_gregset_t *gregsetp, int regno)
{
if (mips_isa_regsize (regcache->arch ()) == 4)
mips_fill_gregset (regcache, (mips_elf_gregset_t *) gregsetp, regno);
else
mips64_fill_gregset (regcache, (mips64_elf_gregset_t *) gregsetp, regno);
}
void
supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
{
mips64_supply_fpregset (regcache, (const mips64_elf_fpregset_t *) fpregsetp);
}
void
fill_fpregset (const struct regcache *regcache,
gdb_fpregset_t *fpregsetp, int regno)
{
mips64_fill_fpregset (regcache, (mips64_elf_fpregset_t *) fpregsetp, regno);
}
/* Fetch REGNO (or all registers if REGNO == -1) from the target
using PTRACE_GETREGS et al. */
void
mips_linux_nat_target::mips64_regsets_fetch_registers
(struct regcache *regcache, int regno)
{
struct gdbarch *gdbarch = regcache->arch ();
int is_fp, is_dsp;
int have_dsp;
int regi;
int tid;
if (regno >= mips_regnum (gdbarch)->fp0
&& regno <= mips_regnum (gdbarch)->fp0 + 32)
is_fp = 1;
else if (regno == mips_regnum (gdbarch)->fp_control_status)
is_fp = 1;
else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
is_fp = 1;
else
is_fp = 0;
/* DSP registers are optional and not a part of any set. */
have_dsp = mips_regnum (gdbarch)->dspctl != -1;
if (!have_dsp)
is_dsp = 0;
else if (regno >= mips_regnum (gdbarch)->dspacc
&& regno < mips_regnum (gdbarch)->dspacc + 6)
is_dsp = 1;
else if (regno == mips_regnum (gdbarch)->dspctl)
is_dsp = 1;
else
is_dsp = 0;
tid = get_ptrace_pid (regcache->ptid ());
if (regno == -1 || (!is_fp && !is_dsp))
{
mips64_elf_gregset_t regs;
if (ptrace (PTRACE_GETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
{
if (errno == EIO)
{
have_ptrace_regsets = 0;
return;
}
perror_with_name (_("Couldn't get registers"));
}
mips64_supply_gregset (regcache,
(const mips64_elf_gregset_t *) &regs);
}
if (regno == -1 || is_fp)
{
mips64_elf_fpregset_t fp_regs;
if (ptrace (PTRACE_GETFPREGS, tid, 0L,
(PTRACE_TYPE_ARG3) &fp_regs) == -1)
{
if (errno == EIO)
{
have_ptrace_regsets = 0;
return;
}
perror_with_name (_("Couldn't get FP registers"));
}
mips64_supply_fpregset (regcache,
(const mips64_elf_fpregset_t *) &fp_regs);
}
if (is_dsp)
linux_nat_trad_target::fetch_registers (regcache, regno);
else if (regno == -1 && have_dsp)
{
for (regi = mips_regnum (gdbarch)->dspacc;
regi < mips_regnum (gdbarch)->dspacc + 6;
regi++)
linux_nat_trad_target::fetch_registers (regcache, regi);
linux_nat_trad_target::fetch_registers (regcache,
mips_regnum (gdbarch)->dspctl);
}
}
/* Store REGNO (or all registers if REGNO == -1) to the target
using PTRACE_SETREGS et al. */
void
mips_linux_nat_target::mips64_regsets_store_registers
(struct regcache *regcache, int regno)
{
struct gdbarch *gdbarch = regcache->arch ();
int is_fp, is_dsp;
int have_dsp;
int regi;
int tid;
if (regno >= mips_regnum (gdbarch)->fp0
&& regno <= mips_regnum (gdbarch)->fp0 + 32)
is_fp = 1;
else if (regno == mips_regnum (gdbarch)->fp_control_status)
is_fp = 1;
else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
is_fp = 1;
else
is_fp = 0;
/* DSP registers are optional and not a part of any set. */
have_dsp = mips_regnum (gdbarch)->dspctl != -1;
if (!have_dsp)
is_dsp = 0;
else if (regno >= mips_regnum (gdbarch)->dspacc
&& regno < mips_regnum (gdbarch)->dspacc + 6)
is_dsp = 1;
else if (regno == mips_regnum (gdbarch)->dspctl)
is_dsp = 1;
else
is_dsp = 0;
tid = get_ptrace_pid (regcache->ptid ());
if (regno == -1 || (!is_fp && !is_dsp))
{
mips64_elf_gregset_t regs;
if (ptrace (PTRACE_GETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
perror_with_name (_("Couldn't get registers"));
mips64_fill_gregset (regcache, &regs, regno);
if (ptrace (PTRACE_SETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
perror_with_name (_("Couldn't set registers"));
}
if (regno == -1 || is_fp)
{
mips64_elf_fpregset_t fp_regs;
if (ptrace (PTRACE_GETFPREGS, tid, 0L,
(PTRACE_TYPE_ARG3) &fp_regs) == -1)
perror_with_name (_("Couldn't get FP registers"));
mips64_fill_fpregset (regcache, &fp_regs, regno);
if (ptrace (PTRACE_SETFPREGS, tid, 0L,
(PTRACE_TYPE_ARG3) &fp_regs) == -1)
perror_with_name (_("Couldn't set FP registers"));
}
if (is_dsp)
linux_nat_trad_target::store_registers (regcache, regno);
else if (regno == -1 && have_dsp)
{
for (regi = mips_regnum (gdbarch)->dspacc;
regi < mips_regnum (gdbarch)->dspacc + 6;
regi++)
linux_nat_trad_target::store_registers (regcache, regi);
linux_nat_trad_target::store_registers (regcache,
mips_regnum (gdbarch)->dspctl);
}
}
/* Fetch REGNO (or all registers if REGNO == -1) from the target
using any working method. */
void
mips_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
{
/* Unless we already know that PTRACE_GETREGS does not work, try it. */
if (have_ptrace_regsets)
mips64_regsets_fetch_registers (regcache, regnum);
/* If we know, or just found out, that PTRACE_GETREGS does not work, fall
back to PTRACE_PEEKUSER. */
if (!have_ptrace_regsets)
{
linux_nat_trad_target::fetch_registers (regcache, regnum);
/* Fill the inaccessible zero register with zero. */
if (regnum == MIPS_ZERO_REGNUM || regnum == -1)
regcache->raw_supply_zeroed (MIPS_ZERO_REGNUM);
}
}
/* Store REGNO (or all registers if REGNO == -1) to the target
using any working method. */
void
mips_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
{
/* Unless we already know that PTRACE_GETREGS does not work, try it. */
if (have_ptrace_regsets)
mips64_regsets_store_registers (regcache, regnum);
/* If we know, or just found out, that PTRACE_GETREGS does not work, fall
back to PTRACE_PEEKUSER. */
if (!have_ptrace_regsets)
linux_nat_trad_target::store_registers (regcache, regnum);
}
/* Return the address in the core dump or inferior of register
REGNO. */
CORE_ADDR
mips_linux_nat_target::register_u_offset (struct gdbarch *gdbarch,
int regno, int store_p)
{
if (mips_abi_regsize (gdbarch) == 8)
return mips64_linux_register_addr (gdbarch, regno, store_p);
else
return mips_linux_register_addr (gdbarch, regno, store_p);
}
const struct target_desc *
mips_linux_nat_target::read_description ()
{
static int have_dsp = -1;
if (have_dsp < 0)
{
int tid = get_ptrace_pid (inferior_ptid);
errno = 0;
ptrace (PTRACE_PEEKUSER, tid, DSP_CONTROL, 0);
switch (errno)
{
case 0:
have_dsp = 1;
break;
case EIO:
have_dsp = 0;
break;
default:
perror_with_name (_("Couldn't check DSP support"));
break;
}
}
/* Report that target registers are a size we know for sure
that we can get from ptrace. */
if (_MIPS_SIM == _ABIO32)
return have_dsp ? tdesc_mips_dsp_linux : tdesc_mips_linux;
else
return have_dsp ? tdesc_mips64_dsp_linux : tdesc_mips64_linux;
}
/* -1 if the kernel and/or CPU do not support watch registers.
1 if watch_readback is valid and we can read style, num_valid
and the masks.
0 if we need to read the watch_readback. */
static int watch_readback_valid;
/* Cached watch register read values. */
static struct pt_watch_regs watch_readback;
static struct mips_watchpoint *current_watches;
/* The current set of watch register values for writing the
registers. */
static struct pt_watch_regs watch_mirror;
static void
mips_show_dr (const char *func, CORE_ADDR addr,
int len, enum target_hw_bp_type type)
{
int i;
puts_unfiltered (func);
if (addr || len)
printf_unfiltered (" (addr=%s, len=%d, type=%s)",
paddress (target_gdbarch (), addr), len,
type == hw_write ? "data-write"
: (type == hw_read ? "data-read"
: (type == hw_access ? "data-read/write"
: (type == hw_execute ? "instruction-execute"
: "??unknown??"))));
puts_unfiltered (":\n");
for (i = 0; i < MAX_DEBUG_REGISTER; i++)
printf_unfiltered ("\tDR%d: lo=%s, hi=%s\n", i,
paddress (target_gdbarch (),
mips_linux_watch_get_watchlo (&watch_mirror,
i)),
paddress (target_gdbarch (),
mips_linux_watch_get_watchhi (&watch_mirror,
i)));
}
/* Target to_can_use_hw_breakpoint implementation. Return 1 if we can
handle the specified watch type. */
int
mips_linux_nat_target::can_use_hw_breakpoint (enum bptype type,
int cnt, int ot)
{
int i;
uint32_t wanted_mask, irw_mask;
if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
&watch_readback,
&watch_readback_valid, 0))
return 0;
switch (type)
{
case bp_hardware_watchpoint:
wanted_mask = W_MASK;
break;
case bp_read_watchpoint:
wanted_mask = R_MASK;
break;
case bp_access_watchpoint:
wanted_mask = R_MASK | W_MASK;
break;
default:
return 0;
}
for (i = 0;
i < mips_linux_watch_get_num_valid (&watch_readback) && cnt;
i++)
{
irw_mask = mips_linux_watch_get_irw_mask (&watch_readback, i);
if ((irw_mask & wanted_mask) == wanted_mask)
cnt--;
}
return (cnt == 0) ? 1 : 0;
}
/* Target to_stopped_by_watchpoint implementation. Return 1 if
stopped by watchpoint. The watchhi R and W bits indicate the watch
register triggered. */
bool
mips_linux_nat_target::stopped_by_watchpoint ()
{
int n;
int num_valid;
if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
&watch_readback,
&watch_readback_valid, 1))
return false;
num_valid = mips_linux_watch_get_num_valid (&watch_readback);
for (n = 0; n < MAX_DEBUG_REGISTER && n < num_valid; n++)
if (mips_linux_watch_get_watchhi (&watch_readback, n) & (R_MASK | W_MASK))
return true;
return false;
}
/* Target to_stopped_data_address implementation. Set the address
where the watch triggered (if known). Return 1 if the address was
known. */
bool
mips_linux_nat_target::stopped_data_address (CORE_ADDR *paddr)
{
/* On mips we don't know the low order 3 bits of the data address,
so we must return false. */
return false;
}
/* Target to_region_ok_for_hw_watchpoint implementation. Return 1 if
the specified region can be covered by the watch registers. */
int
mips_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
{
struct pt_watch_regs dummy_regs;
int i;
if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
&watch_readback,
&watch_readback_valid, 0))
return 0;
dummy_regs = watch_readback;
/* Clear them out. */
for (i = 0; i < mips_linux_watch_get_num_valid (&dummy_regs); i++)
mips_linux_watch_set_watchlo (&dummy_regs, i, 0);
return mips_linux_watch_try_one_watch (&dummy_regs, addr, len, 0);
}
/* Write the mirrored watch register values for each thread. */
static int
write_watchpoint_regs (void)
{
struct lwp_info *lp;
int tid;
ALL_LWPS (lp)
{
tid = lp->ptid.lwp ();
if (ptrace (PTRACE_SET_WATCH_REGS, tid, &watch_mirror, NULL) == -1)
perror_with_name (_("Couldn't write debug register"));
}
return 0;
}
/* linux_nat_target::low_new_thread implementation. Write the
mirrored watch register values for the new thread. */
void
mips_linux_nat_target::low_new_thread (struct lwp_info *lp)
{
long tid = lp->ptid.lwp ();
if (!mips_linux_read_watch_registers (tid,
&watch_readback,
&watch_readback_valid, 0))
return;
if (ptrace (PTRACE_SET_WATCH_REGS, tid, &watch_mirror, NULL) == -1)
perror_with_name (_("Couldn't write debug register"));
}
/* Target to_insert_watchpoint implementation. Try to insert a new
watch. Return zero on success. */
int
mips_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type,
struct expression *cond)
{
struct pt_watch_regs regs;
struct mips_watchpoint *new_watch;
struct mips_watchpoint **pw;
int retval;
if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
&watch_readback,
&watch_readback_valid, 0))
return -1;
if (len <= 0)
return -1;
regs = watch_readback;
/* Add the current watches. */
mips_linux_watch_populate_regs (current_watches, &regs);
/* Now try to add the new watch. */
if (!mips_linux_watch_try_one_watch (&regs, addr, len,
mips_linux_watch_type_to_irw (type)))
return -1;
/* It fit. Stick it on the end of the list. */
new_watch = XNEW (struct mips_watchpoint);
new_watch->addr = addr;
new_watch->len = len;
new_watch->type = type;
new_watch->next = NULL;
pw = &current_watches;
while (*pw != NULL)
pw = &(*pw)->next;
*pw = new_watch;
watch_mirror = regs;
retval = write_watchpoint_regs ();
if (show_debug_regs)
mips_show_dr ("insert_watchpoint", addr, len, type);
return retval;
}
/* Target to_remove_watchpoint implementation. Try to remove a watch.
Return zero on success. */
int
mips_linux_nat_target::remove_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type,
struct expression *cond)
{
int retval;
int deleted_one;
struct mips_watchpoint **pw;
struct mips_watchpoint *w;
/* Search for a known watch that matches. Then unlink and free
it. */
deleted_one = 0;
pw = &current_watches;
while ((w = *pw))
{
if (w->addr == addr && w->len == len && w->type == type)
{
*pw = w->next;
xfree (w);
deleted_one = 1;
break;
}
pw = &(w->next);
}
if (!deleted_one)
return -1; /* We don't know about it, fail doing nothing. */
/* At this point watch_readback is known to be valid because we
could not have added the watch without reading it. */
gdb_assert (watch_readback_valid == 1);
watch_mirror = watch_readback;
mips_linux_watch_populate_regs (current_watches, &watch_mirror);
retval = write_watchpoint_regs ();
if (show_debug_regs)
mips_show_dr ("remove_watchpoint", addr, len, type);
return retval;
}
/* Target to_close implementation. Free any watches and call the
super implementation. */
void
mips_linux_nat_target::close ()
{
struct mips_watchpoint *w;
struct mips_watchpoint *nw;
/* Clean out the current_watches list. */
w = current_watches;
while (w)
{
nw = w->next;
xfree (w);
w = nw;
}
current_watches = NULL;
linux_nat_trad_target::close ();
}
void _initialize_mips_linux_nat ();
void
_initialize_mips_linux_nat ()
{
add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
&show_debug_regs, _("\
Set whether to show variables that mirror the mips debug registers."), _("\
Show whether to show variables that mirror the mips debug registers."), _("\
Use \"on\" to enable, \"off\" to disable.\n\
If enabled, the debug registers values are shown when GDB inserts\n\
or removes a hardware breakpoint or watchpoint, and when the inferior\n\
triggers a breakpoint or watchpoint."),
NULL,
NULL,
&maintenance_set_cmdlist,
&maintenance_show_cmdlist);
linux_target = &the_mips_linux_nat_target;
add_inf_child_target (&the_mips_linux_nat_target);
}