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darling-gdb/gdb/arm-linux-nat.c
Joel Brobecker 28e7fd6234 Update years in copyright notice for the GDB files. 
Two modifications:
  1. The addition of 2013 to the copyright year range for every file;
  2. The use of a single year range, instead of potentially multiple
     year ranges, as approved by the FSF.
2013-01-01 06:33:28 +00:00

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/* GNU/Linux on ARM native support.
Copyright (C) 1999-2013 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 "gdbcore.h"
#include "gdb_string.h"
#include "regcache.h"
#include "target.h"
#include "linux-nat.h"
#include "target-descriptions.h"
#include "auxv.h"
#include "observer.h"
#include "gdbthread.h"
#include "arm-tdep.h"
#include "arm-linux-tdep.h"
#include <elf/common.h>
#include <sys/user.h>
#include <sys/ptrace.h>
#include <sys/utsname.h>
#include <sys/procfs.h>
/* Prototypes for supply_gregset etc. */
#include "gregset.h"
/* Defines ps_err_e, struct ps_prochandle. */
#include "gdb_proc_service.h"
#ifndef PTRACE_GET_THREAD_AREA
#define PTRACE_GET_THREAD_AREA 22
#endif
#ifndef PTRACE_GETWMMXREGS
#define PTRACE_GETWMMXREGS 18
#define PTRACE_SETWMMXREGS 19
#endif
#ifndef PTRACE_GETVFPREGS
#define PTRACE_GETVFPREGS 27
#define PTRACE_SETVFPREGS 28
#endif
#ifndef PTRACE_GETHBPREGS
#define PTRACE_GETHBPREGS 29
#define PTRACE_SETHBPREGS 30
#endif
/* A flag for whether the WMMX registers are available. */
static int arm_linux_has_wmmx_registers;
/* The number of 64-bit VFP registers we have (expect this to be 0,
16, or 32). */
static int arm_linux_vfp_register_count;
extern int arm_apcs_32;
/* On GNU/Linux, threads are implemented as pseudo-processes, in which
case we may be tracing more than one process at a time. In that
case, inferior_ptid will contain the main process ID and the
individual thread (process) ID. get_thread_id () is used to get
the thread id if it's available, and the process id otherwise. */
static int
get_thread_id (ptid_t ptid)
{
int tid = TIDGET (ptid);
if (0 == tid)
tid = PIDGET (ptid);
return tid;
}
#define GET_THREAD_ID(PTID) get_thread_id (PTID)
/* Get the value of a particular register from the floating point
state of the process and store it into regcache. */
static void
fetch_fpregister (struct regcache *regcache, int regno)
{
int ret, tid;
gdb_byte fp[ARM_LINUX_SIZEOF_NWFPE];
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
ret = ptrace (PT_GETFPREGS, tid, 0, fp);
if (ret < 0)
{
warning (_("Unable to fetch floating point register."));
return;
}
/* Fetch fpsr. */
if (ARM_FPS_REGNUM == regno)
regcache_raw_supply (regcache, ARM_FPS_REGNUM,
fp + NWFPE_FPSR_OFFSET);
/* Fetch the floating point register. */
if (regno >= ARM_F0_REGNUM && regno <= ARM_F7_REGNUM)
supply_nwfpe_register (regcache, regno, fp);
}
/* Get the whole floating point state of the process and store it
into regcache. */
static void
fetch_fpregs (struct regcache *regcache)
{
int ret, regno, tid;
gdb_byte fp[ARM_LINUX_SIZEOF_NWFPE];
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
ret = ptrace (PT_GETFPREGS, tid, 0, fp);
if (ret < 0)
{
warning (_("Unable to fetch the floating point registers."));
return;
}
/* Fetch fpsr. */
regcache_raw_supply (regcache, ARM_FPS_REGNUM,
fp + NWFPE_FPSR_OFFSET);
/* Fetch the floating point registers. */
for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++)
supply_nwfpe_register (regcache, regno, fp);
}
/* Save a particular register into the floating point state of the
process using the contents from regcache. */
static void
store_fpregister (const struct regcache *regcache, int regno)
{
int ret, tid;
gdb_byte fp[ARM_LINUX_SIZEOF_NWFPE];
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
ret = ptrace (PT_GETFPREGS, tid, 0, fp);
if (ret < 0)
{
warning (_("Unable to fetch the floating point registers."));
return;
}
/* Store fpsr. */
if (ARM_FPS_REGNUM == regno
&& REG_VALID == regcache_register_status (regcache, ARM_FPS_REGNUM))
regcache_raw_collect (regcache, ARM_FPS_REGNUM, fp + NWFPE_FPSR_OFFSET);
/* Store the floating point register. */
if (regno >= ARM_F0_REGNUM && regno <= ARM_F7_REGNUM)
collect_nwfpe_register (regcache, regno, fp);
ret = ptrace (PTRACE_SETFPREGS, tid, 0, fp);
if (ret < 0)
{
warning (_("Unable to store floating point register."));
return;
}
}
/* Save the whole floating point state of the process using
the contents from regcache. */
static void
store_fpregs (const struct regcache *regcache)
{
int ret, regno, tid;
gdb_byte fp[ARM_LINUX_SIZEOF_NWFPE];
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
/* Read the floating point state. */
ret = ptrace (PT_GETFPREGS, tid, 0, fp);
if (ret < 0)
{
warning (_("Unable to fetch the floating point registers."));
return;
}
/* Store fpsr. */
if (REG_VALID == regcache_register_status (regcache, ARM_FPS_REGNUM))
regcache_raw_collect (regcache, ARM_FPS_REGNUM, fp + NWFPE_FPSR_OFFSET);
/* Store the floating point registers. */
for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++)
if (REG_VALID == regcache_register_status (regcache, regno))
collect_nwfpe_register (regcache, regno, fp);
ret = ptrace (PTRACE_SETFPREGS, tid, 0, fp);
if (ret < 0)
{
warning (_("Unable to store floating point registers."));
return;
}
}
/* Fetch a general register of the process and store into
regcache. */
static void
fetch_register (struct regcache *regcache, int regno)
{
int ret, tid;
elf_gregset_t regs;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
ret = ptrace (PTRACE_GETREGS, tid, 0, &regs);
if (ret < 0)
{
warning (_("Unable to fetch general register."));
return;
}
if (regno >= ARM_A1_REGNUM && regno < ARM_PC_REGNUM)
regcache_raw_supply (regcache, regno, (char *) &regs[regno]);
if (ARM_PS_REGNUM == regno)
{
if (arm_apcs_32)
regcache_raw_supply (regcache, ARM_PS_REGNUM,
(char *) &regs[ARM_CPSR_GREGNUM]);
else
regcache_raw_supply (regcache, ARM_PS_REGNUM,
(char *) &regs[ARM_PC_REGNUM]);
}
if (ARM_PC_REGNUM == regno)
{
regs[ARM_PC_REGNUM] = gdbarch_addr_bits_remove
(get_regcache_arch (regcache),
regs[ARM_PC_REGNUM]);
regcache_raw_supply (regcache, ARM_PC_REGNUM,
(char *) &regs[ARM_PC_REGNUM]);
}
}
/* Fetch all general registers of the process and store into
regcache. */
static void
fetch_regs (struct regcache *regcache)
{
int ret, regno, tid;
elf_gregset_t regs;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
ret = ptrace (PTRACE_GETREGS, tid, 0, &regs);
if (ret < 0)
{
warning (_("Unable to fetch general registers."));
return;
}
for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++)
regcache_raw_supply (regcache, regno, (char *) &regs[regno]);
if (arm_apcs_32)
regcache_raw_supply (regcache, ARM_PS_REGNUM,
(char *) &regs[ARM_CPSR_GREGNUM]);
else
regcache_raw_supply (regcache, ARM_PS_REGNUM,
(char *) &regs[ARM_PC_REGNUM]);
regs[ARM_PC_REGNUM] = gdbarch_addr_bits_remove
(get_regcache_arch (regcache), regs[ARM_PC_REGNUM]);
regcache_raw_supply (regcache, ARM_PC_REGNUM,
(char *) &regs[ARM_PC_REGNUM]);
}
/* Store all general registers of the process from the values in
regcache. */
static void
store_register (const struct regcache *regcache, int regno)
{
int ret, tid;
elf_gregset_t regs;
if (REG_VALID != regcache_register_status (regcache, regno))
return;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
/* Get the general registers from the process. */
ret = ptrace (PTRACE_GETREGS, tid, 0, &regs);
if (ret < 0)
{
warning (_("Unable to fetch general registers."));
return;
}
if (regno >= ARM_A1_REGNUM && regno <= ARM_PC_REGNUM)
regcache_raw_collect (regcache, regno, (char *) &regs[regno]);
else if (arm_apcs_32 && regno == ARM_PS_REGNUM)
regcache_raw_collect (regcache, regno,
(char *) &regs[ARM_CPSR_GREGNUM]);
else if (!arm_apcs_32 && regno == ARM_PS_REGNUM)
regcache_raw_collect (regcache, ARM_PC_REGNUM,
(char *) &regs[ARM_PC_REGNUM]);
ret = ptrace (PTRACE_SETREGS, tid, 0, &regs);
if (ret < 0)
{
warning (_("Unable to store general register."));
return;
}
}
static void
store_regs (const struct regcache *regcache)
{
int ret, regno, tid;
elf_gregset_t regs;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
/* Fetch the general registers. */
ret = ptrace (PTRACE_GETREGS, tid, 0, &regs);
if (ret < 0)
{
warning (_("Unable to fetch general registers."));
return;
}
for (regno = ARM_A1_REGNUM; regno <= ARM_PC_REGNUM; regno++)
{
if (REG_VALID == regcache_register_status (regcache, regno))
regcache_raw_collect (regcache, regno, (char *) &regs[regno]);
}
if (arm_apcs_32 && REG_VALID == regcache_register_status (regcache, ARM_PS_REGNUM))
regcache_raw_collect (regcache, ARM_PS_REGNUM,
(char *) &regs[ARM_CPSR_GREGNUM]);
ret = ptrace (PTRACE_SETREGS, tid, 0, &regs);
if (ret < 0)
{
warning (_("Unable to store general registers."));
return;
}
}
/* Fetch all WMMX registers of the process and store into
regcache. */
#define IWMMXT_REGS_SIZE (16 * 8 + 6 * 4)
static void
fetch_wmmx_regs (struct regcache *regcache)
{
char regbuf[IWMMXT_REGS_SIZE];
int ret, regno, tid;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
ret = ptrace (PTRACE_GETWMMXREGS, tid, 0, regbuf);
if (ret < 0)
{
warning (_("Unable to fetch WMMX registers."));
return;
}
for (regno = 0; regno < 16; regno++)
regcache_raw_supply (regcache, regno + ARM_WR0_REGNUM,
&regbuf[regno * 8]);
for (regno = 0; regno < 2; regno++)
regcache_raw_supply (regcache, regno + ARM_WCSSF_REGNUM,
&regbuf[16 * 8 + regno * 4]);
for (regno = 0; regno < 4; regno++)
regcache_raw_supply (regcache, regno + ARM_WCGR0_REGNUM,
&regbuf[16 * 8 + 2 * 4 + regno * 4]);
}
static void
store_wmmx_regs (const struct regcache *regcache)
{
char regbuf[IWMMXT_REGS_SIZE];
int ret, regno, tid;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
ret = ptrace (PTRACE_GETWMMXREGS, tid, 0, regbuf);
if (ret < 0)
{
warning (_("Unable to fetch WMMX registers."));
return;
}
for (regno = 0; regno < 16; regno++)
if (REG_VALID == regcache_register_status (regcache,
regno + ARM_WR0_REGNUM))
regcache_raw_collect (regcache, regno + ARM_WR0_REGNUM,
&regbuf[regno * 8]);
for (regno = 0; regno < 2; regno++)
if (REG_VALID == regcache_register_status (regcache,
regno + ARM_WCSSF_REGNUM))
regcache_raw_collect (regcache, regno + ARM_WCSSF_REGNUM,
&regbuf[16 * 8 + regno * 4]);
for (regno = 0; regno < 4; regno++)
if (REG_VALID == regcache_register_status (regcache,
regno + ARM_WCGR0_REGNUM))
regcache_raw_collect (regcache, regno + ARM_WCGR0_REGNUM,
&regbuf[16 * 8 + 2 * 4 + regno * 4]);
ret = ptrace (PTRACE_SETWMMXREGS, tid, 0, regbuf);
if (ret < 0)
{
warning (_("Unable to store WMMX registers."));
return;
}
}
/* Fetch and store VFP Registers. The kernel object has space for 32
64-bit registers, and the FPSCR. This is even when on a VFPv2 or
VFPv3D16 target. */
#define VFP_REGS_SIZE (32 * 8 + 4)
static void
fetch_vfp_regs (struct regcache *regcache)
{
char regbuf[VFP_REGS_SIZE];
int ret, regno, tid;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
ret = ptrace (PTRACE_GETVFPREGS, tid, 0, regbuf);
if (ret < 0)
{
warning (_("Unable to fetch VFP registers."));
return;
}
for (regno = 0; regno < arm_linux_vfp_register_count; regno++)
regcache_raw_supply (regcache, regno + ARM_D0_REGNUM,
(char *) regbuf + regno * 8);
regcache_raw_supply (regcache, ARM_FPSCR_REGNUM,
(char *) regbuf + 32 * 8);
}
static void
store_vfp_regs (const struct regcache *regcache)
{
char regbuf[VFP_REGS_SIZE];
int ret, regno, tid;
/* Get the thread id for the ptrace call. */
tid = GET_THREAD_ID (inferior_ptid);
ret = ptrace (PTRACE_GETVFPREGS, tid, 0, regbuf);
if (ret < 0)
{
warning (_("Unable to fetch VFP registers (for update)."));
return;
}
for (regno = 0; regno < arm_linux_vfp_register_count; regno++)
regcache_raw_collect (regcache, regno + ARM_D0_REGNUM,
(char *) regbuf + regno * 8);
regcache_raw_collect (regcache, ARM_FPSCR_REGNUM,
(char *) regbuf + 32 * 8);
ret = ptrace (PTRACE_SETVFPREGS, tid, 0, regbuf);
if (ret < 0)
{
warning (_("Unable to store VFP registers."));
return;
}
}
/* Fetch registers from the child process. Fetch all registers if
regno == -1, otherwise fetch all general registers or all floating
point registers depending upon the value of regno. */
static void
arm_linux_fetch_inferior_registers (struct target_ops *ops,
struct regcache *regcache, int regno)
{
if (-1 == regno)
{
fetch_regs (regcache);
fetch_fpregs (regcache);
if (arm_linux_has_wmmx_registers)
fetch_wmmx_regs (regcache);
if (arm_linux_vfp_register_count > 0)
fetch_vfp_regs (regcache);
}
else
{
if (regno < ARM_F0_REGNUM || regno == ARM_PS_REGNUM)
fetch_register (regcache, regno);
else if (regno >= ARM_F0_REGNUM && regno <= ARM_FPS_REGNUM)
fetch_fpregister (regcache, regno);
else if (arm_linux_has_wmmx_registers
&& regno >= ARM_WR0_REGNUM && regno <= ARM_WCGR7_REGNUM)
fetch_wmmx_regs (regcache);
else if (arm_linux_vfp_register_count > 0
&& regno >= ARM_D0_REGNUM
&& regno <= ARM_D0_REGNUM + arm_linux_vfp_register_count)
fetch_vfp_regs (regcache);
}
}
/* Store registers back into the inferior. Store all registers if
regno == -1, otherwise store all general registers or all floating
point registers depending upon the value of regno. */
static void
arm_linux_store_inferior_registers (struct target_ops *ops,
struct regcache *regcache, int regno)
{
if (-1 == regno)
{
store_regs (regcache);
store_fpregs (regcache);
if (arm_linux_has_wmmx_registers)
store_wmmx_regs (regcache);
if (arm_linux_vfp_register_count > 0)
store_vfp_regs (regcache);
}
else
{
if (regno < ARM_F0_REGNUM || regno == ARM_PS_REGNUM)
store_register (regcache, regno);
else if ((regno >= ARM_F0_REGNUM) && (regno <= ARM_FPS_REGNUM))
store_fpregister (regcache, regno);
else if (arm_linux_has_wmmx_registers
&& regno >= ARM_WR0_REGNUM && regno <= ARM_WCGR7_REGNUM)
store_wmmx_regs (regcache);
else if (arm_linux_vfp_register_count > 0
&& regno >= ARM_D0_REGNUM
&& regno <= ARM_D0_REGNUM + arm_linux_vfp_register_count)
store_vfp_regs (regcache);
}
}
/* Wrapper functions for the standard regset handling, used by
thread debugging. */
void
fill_gregset (const struct regcache *regcache,
gdb_gregset_t *gregsetp, int regno)
{
arm_linux_collect_gregset (NULL, regcache, regno, gregsetp, 0);
}
void
supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
{
arm_linux_supply_gregset (NULL, regcache, -1, gregsetp, 0);
}
void
fill_fpregset (const struct regcache *regcache,
gdb_fpregset_t *fpregsetp, int regno)
{
arm_linux_collect_nwfpe (NULL, regcache, regno, fpregsetp, 0);
}
/* Fill GDB's register array with the floating-point register values
in *fpregsetp. */
void
supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
{
arm_linux_supply_nwfpe (NULL, regcache, -1, fpregsetp, 0);
}
/* Fetch the thread-local storage pointer for libthread_db. */
ps_err_e
ps_get_thread_area (const 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;
}
static const struct target_desc *
arm_linux_read_description (struct target_ops *ops)
{
CORE_ADDR arm_hwcap = 0;
arm_linux_has_wmmx_registers = 0;
arm_linux_vfp_register_count = 0;
if (target_auxv_search (ops, AT_HWCAP, &arm_hwcap) != 1)
{
return NULL;
}
if (arm_hwcap & HWCAP_IWMMXT)
{
arm_linux_has_wmmx_registers = 1;
return tdesc_arm_with_iwmmxt;
}
if (arm_hwcap & HWCAP_VFP)
{
int pid;
char *buf;
const struct target_desc * result = NULL;
/* NEON implies VFPv3-D32 or no-VFP unit. Say that we only support
Neon with VFPv3-D32. */
if (arm_hwcap & HWCAP_NEON)
{
arm_linux_vfp_register_count = 32;
result = tdesc_arm_with_neon;
}
else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPv3D16)) == HWCAP_VFPv3)
{
arm_linux_vfp_register_count = 32;
result = tdesc_arm_with_vfpv3;
}
else
{
arm_linux_vfp_register_count = 16;
result = tdesc_arm_with_vfpv2;
}
/* Now make sure that the kernel supports reading these
registers. Support was added in 2.6.30. */
pid = GET_LWP (inferior_ptid);
errno = 0;
buf = alloca (VFP_REGS_SIZE);
if (ptrace (PTRACE_GETVFPREGS, pid, 0, buf) < 0
&& errno == EIO)
result = NULL;
return result;
}
return NULL;
}
/* Information describing the hardware breakpoint capabilities. */
struct arm_linux_hwbp_cap
{
gdb_byte arch;
gdb_byte max_wp_length;
gdb_byte wp_count;
gdb_byte bp_count;
};
/* Get hold of the Hardware Breakpoint information for the target we are
attached to. Returns NULL if the kernel doesn't support Hardware
breakpoints at all, or a pointer to the information structure. */
static const struct arm_linux_hwbp_cap *
arm_linux_get_hwbp_cap (void)
{
/* The info structure we return. */
static struct arm_linux_hwbp_cap info;
/* Is INFO in a good state? -1 means that no attempt has been made to
initialize INFO; 0 means an attempt has been made, but it failed; 1
means INFO is in an initialized state. */
static int available = -1;
if (available == -1)
{
int tid;
unsigned int val;
tid = GET_THREAD_ID (inferior_ptid);
if (ptrace (PTRACE_GETHBPREGS, tid, 0, &val) < 0)
available = 0;
else
{
info.arch = (gdb_byte)((val >> 24) & 0xff);
info.max_wp_length = (gdb_byte)((val >> 16) & 0xff);
info.wp_count = (gdb_byte)((val >> 8) & 0xff);
info.bp_count = (gdb_byte)(val & 0xff);
available = (info.arch != 0);
}
}
return available == 1 ? &info : NULL;
}
/* How many hardware breakpoints are available? */
static int
arm_linux_get_hw_breakpoint_count (void)
{
const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
return cap != NULL ? cap->bp_count : 0;
}
/* How many hardware watchpoints are available? */
static int
arm_linux_get_hw_watchpoint_count (void)
{
const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
return cap != NULL ? cap->wp_count : 0;
}
/* Have we got a free break-/watch-point available for use? Returns -1 if
there is not an appropriate resource available, otherwise returns 1. */
static int
arm_linux_can_use_hw_breakpoint (int type, int cnt, int ot)
{
if (type == bp_hardware_watchpoint || type == bp_read_watchpoint
|| type == bp_access_watchpoint || type == bp_watchpoint)
{
if (cnt + ot > arm_linux_get_hw_watchpoint_count ())
return -1;
}
else if (type == bp_hardware_breakpoint)
{
if (cnt > arm_linux_get_hw_breakpoint_count ())
return -1;
}
else
gdb_assert (FALSE);
return 1;
}
/* Enum describing the different types of ARM hardware break-/watch-points. */
typedef enum
{
arm_hwbp_break = 0,
arm_hwbp_load = 1,
arm_hwbp_store = 2,
arm_hwbp_access = 3
} arm_hwbp_type;
/* Type describing an ARM Hardware Breakpoint Control register value. */
typedef unsigned int arm_hwbp_control_t;
/* Structure used to keep track of hardware break-/watch-points. */
struct arm_linux_hw_breakpoint
{
/* Address to break on, or being watched. */
unsigned int address;
/* Control register for break-/watch- point. */
arm_hwbp_control_t control;
};
/* Structure containing arrays of the break and watch points which are have
active in each thread.
The Linux ptrace interface to hardware break-/watch-points presents the
values in a vector centred around 0 (which is used fo generic information).
Positive indicies refer to breakpoint addresses/control registers, negative
indices to watchpoint addresses/control registers.
The Linux vector is indexed as follows:
-((i << 1) + 2): Control register for watchpoint i.
-((i << 1) + 1): Address register for watchpoint i.
0: Information register.
((i << 1) + 1): Address register for breakpoint i.
((i << 1) + 2): Control register for breakpoint i.
This structure is used as a per-thread cache of the state stored by the
kernel, so that we don't need to keep calling into the kernel to find a
free breakpoint.
We treat break-/watch-points with their enable bit clear as being deleted.
*/
typedef struct arm_linux_thread_points
{
/* Thread ID. */
int tid;
/* Breakpoints for thread. */
struct arm_linux_hw_breakpoint *bpts;
/* Watchpoint for threads. */
struct arm_linux_hw_breakpoint *wpts;
} *arm_linux_thread_points_p;
DEF_VEC_P (arm_linux_thread_points_p);
/* Vector of hardware breakpoints for each thread. */
VEC(arm_linux_thread_points_p) *arm_threads = NULL;
/* Find the list of hardware break-/watch-points for a thread with id TID.
If no list exists for TID we return NULL if ALLOC_NEW is 0, otherwise we
create a new list and return that. */
static struct arm_linux_thread_points *
arm_linux_find_breakpoints_by_tid (int tid, int alloc_new)
{
int i;
struct arm_linux_thread_points *t;
for (i = 0; VEC_iterate (arm_linux_thread_points_p, arm_threads, i, t); ++i)
{
if (t->tid == tid)
return t;
}
t = NULL;
if (alloc_new)
{
t = xmalloc (sizeof (struct arm_linux_thread_points));
t->tid = tid;
t->bpts = xzalloc (arm_linux_get_hw_breakpoint_count ()
* sizeof (struct arm_linux_hw_breakpoint));
t->wpts = xzalloc (arm_linux_get_hw_watchpoint_count ()
* sizeof (struct arm_linux_hw_breakpoint));
VEC_safe_push (arm_linux_thread_points_p, arm_threads, t);
}
return t;
}
/* Initialize an ARM hardware break-/watch-point control register value.
BYTE_ADDRESS_SELECT is the mask of bytes to trigger on; HWBP_TYPE is the
type of break-/watch-point; ENABLE indicates whether the point is enabled.
*/
static arm_hwbp_control_t
arm_hwbp_control_initialize (unsigned byte_address_select,
arm_hwbp_type hwbp_type,
int enable)
{
gdb_assert ((byte_address_select & ~0xffU) == 0);
gdb_assert (hwbp_type != arm_hwbp_break
|| ((byte_address_select & 0xfU) != 0));
return (byte_address_select << 5) | (hwbp_type << 3) | (3 << 1) | enable;
}
/* Does the breakpoint control value CONTROL have the enable bit set? */
static int
arm_hwbp_control_is_enabled (arm_hwbp_control_t control)
{
return control & 0x1;
}
/* Change a breakpoint control word so that it is in the disabled state. */
static arm_hwbp_control_t
arm_hwbp_control_disable (arm_hwbp_control_t control)
{
return control & ~0x1;
}
/* Initialise the hardware breakpoint structure P. The breakpoint will be
enabled, and will point to the placed address of BP_TGT. */
static void
arm_linux_hw_breakpoint_initialize (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt,
struct arm_linux_hw_breakpoint *p)
{
unsigned mask;
CORE_ADDR address = bp_tgt->placed_address;
/* We have to create a mask for the control register which says which bits
of the word pointed to by address to break on. */
if (arm_pc_is_thumb (gdbarch, address))
{
mask = 0x3;
address &= ~1;
}
else
{
mask = 0xf;
address &= ~3;
}
p->address = (unsigned int) address;
p->control = arm_hwbp_control_initialize (mask, arm_hwbp_break, 1);
}
/* Get the ARM hardware breakpoint type from the RW value we're given when
asked to set a watchpoint. */
static arm_hwbp_type
arm_linux_get_hwbp_type (int rw)
{
if (rw == hw_read)
return arm_hwbp_load;
else if (rw == hw_write)
return arm_hwbp_store;
else
return arm_hwbp_access;
}
/* Initialize the hardware breakpoint structure P for a watchpoint at ADDR
to LEN. The type of watchpoint is given in RW. */
static void
arm_linux_hw_watchpoint_initialize (CORE_ADDR addr, int len, int rw,
struct arm_linux_hw_breakpoint *p)
{
const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
unsigned mask;
gdb_assert (cap != NULL);
gdb_assert (cap->max_wp_length != 0);
mask = (1 << len) - 1;
p->address = (unsigned int) addr;
p->control = arm_hwbp_control_initialize (mask,
arm_linux_get_hwbp_type (rw), 1);
}
/* Are two break-/watch-points equal? */
static int
arm_linux_hw_breakpoint_equal (const struct arm_linux_hw_breakpoint *p1,
const struct arm_linux_hw_breakpoint *p2)
{
return p1->address == p2->address && p1->control == p2->control;
}
/* Insert the hardware breakpoint (WATCHPOINT = 0) or watchpoint (WATCHPOINT
=1) BPT for thread TID. */
static void
arm_linux_insert_hw_breakpoint1 (const struct arm_linux_hw_breakpoint* bpt,
int tid, int watchpoint)
{
struct arm_linux_thread_points *t = arm_linux_find_breakpoints_by_tid (tid, 1);
gdb_byte count, i;
struct arm_linux_hw_breakpoint* bpts;
int dir;
gdb_assert (t != NULL);
if (watchpoint)
{
count = arm_linux_get_hw_watchpoint_count ();
bpts = t->wpts;
dir = -1;
}
else
{
count = arm_linux_get_hw_breakpoint_count ();
bpts = t->bpts;
dir = 1;
}
for (i = 0; i < count; ++i)
if (!arm_hwbp_control_is_enabled (bpts[i].control))
{
errno = 0;
if (ptrace (PTRACE_SETHBPREGS, tid, dir * ((i << 1) + 1),
&bpt->address) < 0)
perror_with_name (_("Unexpected error setting breakpoint address"));
if (ptrace (PTRACE_SETHBPREGS, tid, dir * ((i << 1) + 2),
&bpt->control) < 0)
perror_with_name (_("Unexpected error setting breakpoint"));
memcpy (bpts + i, bpt, sizeof (struct arm_linux_hw_breakpoint));
break;
}
gdb_assert (i != count);
}
/* Remove the hardware breakpoint (WATCHPOINT = 0) or watchpoint
(WATCHPOINT = 1) BPT for thread TID. */
static void
arm_linux_remove_hw_breakpoint1 (const struct arm_linux_hw_breakpoint *bpt,
int tid, int watchpoint)
{
struct arm_linux_thread_points *t = arm_linux_find_breakpoints_by_tid (tid, 0);
gdb_byte count, i;
struct arm_linux_hw_breakpoint *bpts;
int dir;
gdb_assert (t != NULL);
if (watchpoint)
{
count = arm_linux_get_hw_watchpoint_count ();
bpts = t->wpts;
dir = -1;
}
else
{
count = arm_linux_get_hw_breakpoint_count ();
bpts = t->bpts;
dir = 1;
}
for (i = 0; i < count; ++i)
if (arm_linux_hw_breakpoint_equal (bpt, bpts + i))
{
errno = 0;
bpts[i].control = arm_hwbp_control_disable (bpts[i].control);
if (ptrace (PTRACE_SETHBPREGS, tid, dir * ((i << 1) + 2),
&bpts[i].control) < 0)
perror_with_name (_("Unexpected error clearing breakpoint"));
break;
}
gdb_assert (i != count);
}
/* Insert a Hardware breakpoint. */
static int
arm_linux_insert_hw_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
struct lwp_info *lp;
struct arm_linux_hw_breakpoint p;
if (arm_linux_get_hw_breakpoint_count () == 0)
return -1;
arm_linux_hw_breakpoint_initialize (gdbarch, bp_tgt, &p);
ALL_LWPS (lp)
arm_linux_insert_hw_breakpoint1 (&p, TIDGET (lp->ptid), 0);
return 0;
}
/* Remove a hardware breakpoint. */
static int
arm_linux_remove_hw_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
struct lwp_info *lp;
struct arm_linux_hw_breakpoint p;
if (arm_linux_get_hw_breakpoint_count () == 0)
return -1;
arm_linux_hw_breakpoint_initialize (gdbarch, bp_tgt, &p);
ALL_LWPS (lp)
arm_linux_remove_hw_breakpoint1 (&p, TIDGET (lp->ptid), 0);
return 0;
}
/* Are we able to use a hardware watchpoint for the LEN bytes starting at
ADDR? */
static int
arm_linux_region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
{
const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
CORE_ADDR max_wp_length, aligned_addr;
/* Can not set watchpoints for zero or negative lengths. */
if (len <= 0)
return 0;
/* Need to be able to use the ptrace interface. */
if (cap == NULL || cap->wp_count == 0)
return 0;
/* Test that the range [ADDR, ADDR + LEN) fits into the largest address
range covered by a watchpoint. */
max_wp_length = (CORE_ADDR)cap->max_wp_length;
aligned_addr = addr & ~(max_wp_length - 1);
if (aligned_addr + max_wp_length < addr + len)
return 0;
/* The current ptrace interface can only handle watchpoints that are a
power of 2. */
if ((len & (len - 1)) != 0)
return 0;
/* All tests passed so we must be able to set a watchpoint. */
return 1;
}
/* Insert a Hardware breakpoint. */
static int
arm_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw,
struct expression *cond)
{
struct lwp_info *lp;
struct arm_linux_hw_breakpoint p;
if (arm_linux_get_hw_watchpoint_count () == 0)
return -1;
arm_linux_hw_watchpoint_initialize (addr, len, rw, &p);
ALL_LWPS (lp)
arm_linux_insert_hw_breakpoint1 (&p, TIDGET (lp->ptid), 1);
return 0;
}
/* Remove a hardware breakpoint. */
static int
arm_linux_remove_watchpoint (CORE_ADDR addr, int len, int rw,
struct expression *cond)
{
struct lwp_info *lp;
struct arm_linux_hw_breakpoint p;
if (arm_linux_get_hw_watchpoint_count () == 0)
return -1;
arm_linux_hw_watchpoint_initialize (addr, len, rw, &p);
ALL_LWPS (lp)
arm_linux_remove_hw_breakpoint1 (&p, TIDGET (lp->ptid), 1);
return 0;
}
/* What was the data address the target was stopped on accessing. */
static int
arm_linux_stopped_data_address (struct target_ops *target, CORE_ADDR *addr_p)
{
siginfo_t siginfo;
int slot;
if (!linux_nat_get_siginfo (inferior_ptid, &siginfo))
return 0;
/* This must be a hardware breakpoint. */
if (siginfo.si_signo != SIGTRAP
|| (siginfo.si_code & 0xffff) != 0x0004 /* TRAP_HWBKPT */)
return 0;
/* We must be able to set hardware watchpoints. */
if (arm_linux_get_hw_watchpoint_count () == 0)
return 0;
slot = siginfo.si_errno;
/* If we are in a positive slot then we're looking at a breakpoint and not
a watchpoint. */
if (slot >= 0)
return 0;
*addr_p = (CORE_ADDR) (uintptr_t) siginfo.si_addr;
return 1;
}
/* Has the target been stopped by hitting a watchpoint? */
static int
arm_linux_stopped_by_watchpoint (void)
{
CORE_ADDR addr;
return arm_linux_stopped_data_address (&current_target, &addr);
}
static int
arm_linux_watchpoint_addr_within_range (struct target_ops *target,
CORE_ADDR addr,
CORE_ADDR start, int length)
{
return start <= addr && start + length - 1 >= addr;
}
/* Handle thread creation. We need to copy the breakpoints and watchpoints
in the parent thread to the child thread. */
static void
arm_linux_new_thread (struct lwp_info *lp)
{
int tid = TIDGET (lp->ptid);
const struct arm_linux_hwbp_cap *info = arm_linux_get_hwbp_cap ();
if (info != NULL)
{
int i;
struct arm_linux_thread_points *p;
struct arm_linux_hw_breakpoint *bpts;
if (VEC_empty (arm_linux_thread_points_p, arm_threads))
return;
/* Get a list of breakpoints from any thread. */
p = VEC_last (arm_linux_thread_points_p, arm_threads);
/* Copy that thread's breakpoints and watchpoints to the new thread. */
for (i = 0; i < info->bp_count; i++)
if (arm_hwbp_control_is_enabled (p->bpts[i].control))
arm_linux_insert_hw_breakpoint1 (p->bpts + i, tid, 0);
for (i = 0; i < info->wp_count; i++)
if (arm_hwbp_control_is_enabled (p->wpts[i].control))
arm_linux_insert_hw_breakpoint1 (p->wpts + i, tid, 1);
}
}
/* Handle thread exit. Tidy up the memory that has been allocated for the
thread. */
static void
arm_linux_thread_exit (struct thread_info *tp, int silent)
{
const struct arm_linux_hwbp_cap *info = arm_linux_get_hwbp_cap ();
if (info != NULL)
{
int i;
int tid = TIDGET (tp->ptid);
struct arm_linux_thread_points *t = NULL, *p;
for (i = 0;
VEC_iterate (arm_linux_thread_points_p, arm_threads, i, p); i++)
{
if (p->tid == tid)
{
t = p;
break;
}
}
if (t == NULL)
return;
VEC_unordered_remove (arm_linux_thread_points_p, arm_threads, i);
xfree (t->bpts);
xfree (t->wpts);
xfree (t);
}
}
void _initialize_arm_linux_nat (void);
void
_initialize_arm_linux_nat (void)
{
struct target_ops *t;
/* Fill in the generic GNU/Linux methods. */
t = linux_target ();
/* Add our register access methods. */
t->to_fetch_registers = arm_linux_fetch_inferior_registers;
t->to_store_registers = arm_linux_store_inferior_registers;
/* Add our hardware breakpoint and watchpoint implementation. */
t->to_can_use_hw_breakpoint = arm_linux_can_use_hw_breakpoint;
t->to_insert_hw_breakpoint = arm_linux_insert_hw_breakpoint;
t->to_remove_hw_breakpoint = arm_linux_remove_hw_breakpoint;
t->to_region_ok_for_hw_watchpoint = arm_linux_region_ok_for_hw_watchpoint;
t->to_insert_watchpoint = arm_linux_insert_watchpoint;
t->to_remove_watchpoint = arm_linux_remove_watchpoint;
t->to_stopped_by_watchpoint = arm_linux_stopped_by_watchpoint;
t->to_stopped_data_address = arm_linux_stopped_data_address;
t->to_watchpoint_addr_within_range = arm_linux_watchpoint_addr_within_range;
t->to_read_description = arm_linux_read_description;
/* Register the target. */
linux_nat_add_target (t);
/* Handle thread creation and exit */
observer_attach_thread_exit (arm_linux_thread_exit);
linux_nat_set_new_thread (t, arm_linux_new_thread);
}
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