/* Native-dependent code for the i386.
- Copyright 2001, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2001-2014 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 2 of the License, or
+ 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,
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, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
+#include "i386-nat.h"
#include "breakpoint.h"
#include "command.h"
#include "gdbcmd.h"
+#include "target.h"
+#include "gdb_assert.h"
+#include "inferior.h"
/* Support for hardware watchpoints and breakpoints using the i386
debug registers.
more of the watchpoints triggered and at what address, checking
whether a given region can be watched, etc.
- A target which wants to use these functions should define several
- macros, such as `target_insert_watchpoint' and
- `target_stopped_data_address', listed in target.h, to call the
- appropriate functions below. It should also define
- I386_USE_GENERIC_WATCHPOINTS in its tm.h file.
-
- In addition, each target should provide several low-level macros
- that will be called to insert watchpoints and hardware breakpoints
- into the inferior, remove them, and check their status. These
- macros are:
-
- I386_DR_LOW_SET_CONTROL -- set the debug control (DR7)
- register to a given value
-
- I386_DR_LOW_SET_ADDR -- put an address into one debug
- register
-
- I386_DR_LOW_RESET_ADDR -- reset the address stored in
- one debug register
-
- I386_DR_LOW_GET_STATUS -- return the value of the debug
- status (DR6) register.
-
The functions below implement debug registers sharing by reference
counts, and allow to watch regions up to 16 bytes long. */
-#ifdef I386_USE_GENERIC_WATCHPOINTS
+struct i386_dr_low_type i386_dr_low;
-/* Support for 8-byte wide hw watchpoints. */
-#ifndef TARGET_HAS_DR_LEN_8
-#define TARGET_HAS_DR_LEN_8 0
-#endif
-/* Debug registers' indices. */
-#define DR_NADDR 4 /* The number of debug address registers. */
-#define DR_STATUS 6 /* Index of debug status register (DR6). */
-#define DR_CONTROL 7 /* Index of debug control register (DR7). */
+/* Support for 8-byte wide hw watchpoints. */
+#define TARGET_HAS_DR_LEN_8 (i386_dr_low.debug_register_length == 8)
/* DR7 Debug Control register fields. */
/* The I'th debug register is vacant if its Local and Global Enable
bits are reset in the Debug Control register. */
-#define I386_DR_VACANT(i) \
- ((dr_control_mirror & (3 << (DR_ENABLE_SIZE * (i)))) == 0)
+#define I386_DR_VACANT(state, i) \
+ (((state)->dr_control_mirror & (3 << (DR_ENABLE_SIZE * (i)))) == 0)
/* Locally enable the break/watchpoint in the I'th debug register. */
-#define I386_DR_LOCAL_ENABLE(i) \
- dr_control_mirror |= (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i)))
+#define I386_DR_LOCAL_ENABLE(state, i) \
+ do { \
+ (state)->dr_control_mirror |= \
+ (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))); \
+ } while (0)
/* Globally enable the break/watchpoint in the I'th debug register. */
-#define I386_DR_GLOBAL_ENABLE(i) \
- dr_control_mirror |= (1 << (DR_GLOBAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i)))
+#define I386_DR_GLOBAL_ENABLE(state, i) \
+ do { \
+ (state)->dr_control_mirror |= \
+ (1 << (DR_GLOBAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))); \
+ } while (0)
/* Disable the break/watchpoint in the I'th debug register. */
-#define I386_DR_DISABLE(i) \
- dr_control_mirror &= ~(3 << (DR_ENABLE_SIZE * (i)))
+#define I386_DR_DISABLE(state, i) \
+ do { \
+ (state)->dr_control_mirror &= \
+ ~(3 << (DR_ENABLE_SIZE * (i))); \
+ } while (0)
/* Set in DR7 the RW and LEN fields for the I'th debug register. */
-#define I386_DR_SET_RW_LEN(i,rwlen) \
+#define I386_DR_SET_RW_LEN(state, i, rwlen) \
do { \
- dr_control_mirror &= ~(0x0f << (DR_CONTROL_SHIFT+DR_CONTROL_SIZE*(i))); \
- dr_control_mirror |= ((rwlen) << (DR_CONTROL_SHIFT+DR_CONTROL_SIZE*(i))); \
+ (state)->dr_control_mirror &= \
+ ~(0x0f << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))); \
+ (state)->dr_control_mirror |= \
+ ((rwlen) << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))); \
} while (0)
/* Get from DR7 the RW and LEN fields for the I'th debug register. */
-#define I386_DR_GET_RW_LEN(i) \
- ((dr_control_mirror >> (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))) & 0x0f)
+#define I386_DR_GET_RW_LEN(dr7, i) \
+ (((dr7) \
+ >> (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))) & 0x0f)
+
+/* Mask that this I'th watchpoint has triggered. */
+#define I386_DR_WATCH_MASK(i) (1 << (i))
/* Did the watchpoint whose address is in the I'th register break? */
-#define I386_DR_WATCH_HIT(i) (dr_status_mirror & (1 << (i)))
+#define I386_DR_WATCH_HIT(dr6, i) ((dr6) & (1 << (i)))
/* A macro to loop over all debug registers. */
#define ALL_DEBUG_REGISTERS(i) for (i = 0; i < DR_NADDR; i++)
-/* Mirror the inferior's DRi registers. We keep the status and
- control registers separated because they don't hold addresses. */
-static CORE_ADDR dr_mirror[DR_NADDR];
-static unsigned dr_status_mirror, dr_control_mirror;
+/* Per-process data. We don't bind this to a per-inferior registry
+ because of targets like x86 GNU/Linux that need to keep track of
+ processes that aren't bound to any inferior (e.g., fork children,
+ checkpoints). */
-/* Reference counts for each debug register. */
-static int dr_ref_count[DR_NADDR];
+struct i386_process_info
+{
+ /* Linked list. */
+ struct i386_process_info *next;
+
+ /* The process identifier. */
+ pid_t pid;
+
+ /* Copy of i386 hardware debug registers. */
+ struct i386_debug_reg_state state;
+};
+
+static struct i386_process_info *i386_process_list = NULL;
+
+/* Find process data for process PID. */
+
+static struct i386_process_info *
+i386_find_process_pid (pid_t pid)
+{
+ struct i386_process_info *proc;
+
+ for (proc = i386_process_list; proc; proc = proc->next)
+ if (proc->pid == pid)
+ return proc;
+
+ return NULL;
+}
+
+/* Add process data for process PID. Returns newly allocated info
+ object. */
+
+static struct i386_process_info *
+i386_add_process (pid_t pid)
+{
+ struct i386_process_info *proc;
+
+ proc = xcalloc (1, sizeof (*proc));
+ proc->pid = pid;
+
+ proc->next = i386_process_list;
+ i386_process_list = proc;
+
+ return proc;
+}
+
+/* Get data specific info for process PID, creating it if necessary.
+ Never returns NULL. */
+
+static struct i386_process_info *
+i386_process_info_get (pid_t pid)
+{
+ struct i386_process_info *proc;
+
+ proc = i386_find_process_pid (pid);
+ if (proc == NULL)
+ proc = i386_add_process (pid);
+
+ return proc;
+}
+
+/* Get debug registers state for process PID. */
+
+struct i386_debug_reg_state *
+i386_debug_reg_state (pid_t pid)
+{
+ return &i386_process_info_get (pid)->state;
+}
+
+/* See declaration in i386-nat.h. */
+
+void
+i386_forget_process (pid_t pid)
+{
+ struct i386_process_info *proc, **proc_link;
+
+ proc = i386_process_list;
+ proc_link = &i386_process_list;
+
+ while (proc != NULL)
+ {
+ if (proc->pid == pid)
+ {
+ *proc_link = proc->next;
+
+ xfree (proc);
+ return;
+ }
+
+ proc_link = &proc->next;
+ proc = *proc_link;
+ }
+}
/* Whether or not to print the mirrored debug registers. */
static int maint_show_dr;
value of the bit-field from DR7 which describes the length and
access type of the region to be watched by this watchpoint. Return
0 on success, -1 on failure. */
-static int i386_insert_aligned_watchpoint (CORE_ADDR addr,
+static int i386_insert_aligned_watchpoint (struct i386_debug_reg_state *state,
+ CORE_ADDR addr,
unsigned len_rw_bits);
/* Remove a watchpoint at address ADDR, which is assumed to be aligned
value of the bits from DR7 which describes the length and access
type of the region watched by this watchpoint. Return 0 on
success, -1 on failure. */
-static int i386_remove_aligned_watchpoint (CORE_ADDR addr,
+static int i386_remove_aligned_watchpoint (struct i386_debug_reg_state *state,
+ CORE_ADDR addr,
unsigned len_rw_bits);
/* Insert or remove a (possibly non-aligned) watchpoint, or count the
successful insertion or removal, a positive number when queried
about the number of registers, or -1 on failure. If WHAT is not a
valid value, bombs through internal_error. */
-static int i386_handle_nonaligned_watchpoint (i386_wp_op_t what,
+static int i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state,
+ i386_wp_op_t what,
CORE_ADDR addr, int len,
enum target_hw_bp_type type);
void
i386_cleanup_dregs (void)
{
- int i;
-
- ALL_DEBUG_REGISTERS(i)
- {
- dr_mirror[i] = 0;
- dr_ref_count[i] = 0;
- }
- dr_control_mirror = 0;
- dr_status_mirror = 0;
-}
-
-#ifndef LINUX_CHILD_POST_STARTUP_INFERIOR
-
-/* Reset all debug registers at each new startup to avoid missing
- watchpoints after restart. */
-
-void
-child_post_startup_inferior (ptid_t ptid)
-{
- i386_cleanup_dregs ();
+ /* Starting from scratch has the same effect. */
+ i386_forget_process (ptid_get_pid (inferior_ptid));
}
-#endif /* LINUX_CHILD_POST_STARTUP_INFERIOR */
-
/* Print the values of the mirrored debug registers. This is called
when maint_show_dr is non-zero. To set that up, type "maint
show-debug-regs" at GDB's prompt. */
static void
-i386_show_dr (const char *func, CORE_ADDR addr,
+i386_show_dr (struct i386_debug_reg_state *state,
+ const char *func, CORE_ADDR addr,
int len, enum target_hw_bp_type type)
{
+ int addr_size = gdbarch_addr_bit (target_gdbarch ()) / 8;
int i;
puts_unfiltered (func);
here. */
: "??unknown??"))));
puts_unfiltered (":\n");
- printf_unfiltered ("\tCONTROL (DR7): %08x STATUS (DR6): %08x\n",
- dr_control_mirror, dr_status_mirror);
+ printf_unfiltered ("\tCONTROL (DR7): %s STATUS (DR6): %s\n",
+ phex (state->dr_control_mirror, 8),
+ phex (state->dr_status_mirror, 8));
ALL_DEBUG_REGISTERS(i)
{
printf_unfiltered ("\
\tDR%d: addr=0x%s, ref.count=%d DR%d: addr=0x%s, ref.count=%d\n",
- i, paddr(dr_mirror[i]), dr_ref_count[i],
- i+1, paddr(dr_mirror[i+1]), dr_ref_count[i+1]);
+ i, phex (state->dr_mirror[i], addr_size),
+ state->dr_ref_count[i],
+ i + 1, phex (state->dr_mirror[i + 1], addr_size),
+ state->dr_ref_count[i+1]);
i++;
}
}
rw = DR_RW_WRITE;
break;
case hw_read:
- /* The i386 doesn't support data-read watchpoints. */
+ internal_error (__FILE__, __LINE__,
+ _("The i386 doesn't support "
+ "data-read watchpoints.\n"));
case hw_access:
rw = DR_RW_READ;
break;
break;
#endif
default:
- internal_error (__FILE__, __LINE__, "\
-Invalid hardware breakpoint type %d in i386_length_and_rw_bits.\n",
+ internal_error (__FILE__, __LINE__, _("\
+Invalid hardware breakpoint type %d in i386_length_and_rw_bits.\n"),
(int) type);
}
case 8:
if (TARGET_HAS_DR_LEN_8)
return (DR_LEN_8 | rw);
+ /* ELSE FALL THROUGH */
default:
- internal_error (__FILE__, __LINE__, "\
-Invalid hardware breakpoint length %d in i386_length_and_rw_bits.\n", len);
+ internal_error (__FILE__, __LINE__, _("\
+Invalid hardware breakpoint length %d in i386_length_and_rw_bits.\n"), len);
}
}
success, -1 on failure. */
static int
-i386_insert_aligned_watchpoint (CORE_ADDR addr, unsigned len_rw_bits)
+i386_insert_aligned_watchpoint (struct i386_debug_reg_state *state,
+ CORE_ADDR addr, unsigned len_rw_bits)
{
int i;
+ if (!i386_dr_low.set_addr || !i386_dr_low.set_control)
+ return -1;
+
/* First, look for an occupied debug register with the same address
and the same RW and LEN definitions. If we find one, we can
reuse it for this watchpoint as well (and save a register). */
ALL_DEBUG_REGISTERS(i)
{
- if (!I386_DR_VACANT (i)
- && dr_mirror[i] == addr
- && I386_DR_GET_RW_LEN (i) == len_rw_bits)
+ if (!I386_DR_VACANT (state, i)
+ && state->dr_mirror[i] == addr
+ && I386_DR_GET_RW_LEN (state->dr_control_mirror, i) == len_rw_bits)
{
- dr_ref_count[i]++;
+ state->dr_ref_count[i]++;
return 0;
}
}
/* Next, look for a vacant debug register. */
ALL_DEBUG_REGISTERS(i)
{
- if (I386_DR_VACANT (i))
+ if (I386_DR_VACANT (state, i))
break;
}
/* Now set up the register I to watch our region. */
/* Record the info in our local mirrored array. */
- dr_mirror[i] = addr;
- dr_ref_count[i] = 1;
- I386_DR_SET_RW_LEN (i, len_rw_bits);
+ state->dr_mirror[i] = addr;
+ state->dr_ref_count[i] = 1;
+ I386_DR_SET_RW_LEN (state, i, len_rw_bits);
/* Note: we only enable the watchpoint locally, i.e. in the current
task. Currently, no i386 target allows or supports global
watchpoints; however, if any target would want that in the
to enable watchpoints globally or locally, and the code below
should use global or local enable and slow-down flags as
appropriate. */
- I386_DR_LOCAL_ENABLE (i);
- dr_control_mirror |= DR_LOCAL_SLOWDOWN;
- dr_control_mirror &= I386_DR_CONTROL_MASK;
-
- /* Finally, actually pass the info to the inferior. */
- I386_DR_LOW_SET_ADDR (i, addr);
- I386_DR_LOW_SET_CONTROL (dr_control_mirror);
+ I386_DR_LOCAL_ENABLE (state, i);
+ state->dr_control_mirror |= DR_LOCAL_SLOWDOWN;
+ state->dr_control_mirror &= I386_DR_CONTROL_MASK;
return 0;
}
success, -1 on failure. */
static int
-i386_remove_aligned_watchpoint (CORE_ADDR addr, unsigned len_rw_bits)
+i386_remove_aligned_watchpoint (struct i386_debug_reg_state *state,
+ CORE_ADDR addr, unsigned len_rw_bits)
{
int i, retval = -1;
ALL_DEBUG_REGISTERS(i)
{
- if (!I386_DR_VACANT (i)
- && dr_mirror[i] == addr
- && I386_DR_GET_RW_LEN (i) == len_rw_bits)
+ if (!I386_DR_VACANT (state, i)
+ && state->dr_mirror[i] == addr
+ && I386_DR_GET_RW_LEN (state->dr_control_mirror, i) == len_rw_bits)
{
- if (--dr_ref_count[i] == 0) /* no longer in use? */
+ if (--state->dr_ref_count[i] == 0) /* no longer in use? */
{
/* Reset our mirror. */
- dr_mirror[i] = 0;
- I386_DR_DISABLE (i);
- /* Reset it in the inferior. */
- I386_DR_LOW_SET_CONTROL (dr_control_mirror);
- I386_DR_LOW_RESET_ADDR (i);
+ state->dr_mirror[i] = 0;
+ I386_DR_DISABLE (state, i);
}
retval = 0;
}
valid value, bombs through internal_error. */
static int
-i386_handle_nonaligned_watchpoint (i386_wp_op_t what, CORE_ADDR addr, int len,
+i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state,
+ i386_wp_op_t what, CORE_ADDR addr, int len,
enum target_hw_bp_type type)
{
- int retval = 0, status = 0;
+ int retval = 0;
int max_wp_len = TARGET_HAS_DR_LEN_8 ? 8 : 4;
static int size_try_array[8][8] =
unsigned len_rw = i386_length_and_rw_bits (size, type);
if (what == WP_INSERT)
- status = i386_insert_aligned_watchpoint (addr, len_rw);
+ retval = i386_insert_aligned_watchpoint (state, addr, len_rw);
else if (what == WP_REMOVE)
- status = i386_remove_aligned_watchpoint (addr, len_rw);
+ retval = i386_remove_aligned_watchpoint (state, addr, len_rw);
else
- internal_error (__FILE__, __LINE__, "\
-Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n",
+ internal_error (__FILE__, __LINE__, _("\
+Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n"),
(int)what);
- /* We keep the loop going even after a failure, because some
- of the other aligned watchpoints might still succeed
- (e.g. if they watch addresses that are already watched,
- in which case we just increment the reference counts of
- occupied debug registers). If we break out of the loop
- too early, we could cause those addresses watched by
- other watchpoints to be disabled when breakpoint.c reacts
- to our failure to insert this watchpoint and tries to
- remove it. */
- if (status)
- retval = status;
+ if (retval)
+ break;
}
addr += size;
return retval;
}
+/* Update the inferior's debug registers with the new debug registers
+ state, in NEW_STATE, and then update our local mirror to match. */
+
+static void
+i386_update_inferior_debug_regs (struct i386_debug_reg_state *new_state)
+{
+ struct i386_debug_reg_state *state
+ = i386_debug_reg_state (ptid_get_pid (inferior_ptid));
+ int i;
+
+ ALL_DEBUG_REGISTERS (i)
+ {
+ if (I386_DR_VACANT (new_state, i) != I386_DR_VACANT (state, i))
+ i386_dr_low.set_addr (i, new_state->dr_mirror[i]);
+ else
+ gdb_assert (new_state->dr_mirror[i] == state->dr_mirror[i]);
+ }
+
+ if (new_state->dr_control_mirror != state->dr_control_mirror)
+ i386_dr_low.set_control (new_state->dr_control_mirror);
+
+ *state = *new_state;
+}
+
/* Insert a watchpoint to watch a memory region which starts at
address ADDR and whose length is LEN bytes. Watch memory accesses
of the type TYPE. Return 0 on success, -1 on failure. */
-int
-i386_insert_watchpoint (CORE_ADDR addr, int len, int type)
+static int
+i386_insert_watchpoint (CORE_ADDR addr, int len, int type,
+ struct expression *cond)
{
+ struct i386_debug_reg_state *state
+ = i386_debug_reg_state (ptid_get_pid (inferior_ptid));
int retval;
+ /* Work on a local copy of the debug registers, and on success,
+ commit the change back to the inferior. */
+ struct i386_debug_reg_state local_state = *state;
+
+ if (type == hw_read)
+ return 1; /* unsupported */
if (((len != 1 && len !=2 && len !=4) && !(TARGET_HAS_DR_LEN_8 && len == 8))
|| addr % len != 0)
- retval = i386_handle_nonaligned_watchpoint (WP_INSERT, addr, len, type);
+ retval = i386_handle_nonaligned_watchpoint (&local_state,
+ WP_INSERT, addr, len, type);
else
{
unsigned len_rw = i386_length_and_rw_bits (len, type);
- retval = i386_insert_aligned_watchpoint (addr, len_rw);
+ retval = i386_insert_aligned_watchpoint (&local_state,
+ addr, len_rw);
}
+ if (retval == 0)
+ i386_update_inferior_debug_regs (&local_state);
+
if (maint_show_dr)
- i386_show_dr ("insert_watchpoint", addr, len, type);
+ i386_show_dr (state, "insert_watchpoint", addr, len, type);
return retval;
}
/* Remove a watchpoint that watched the memory region which starts at
address ADDR, whose length is LEN bytes, and for accesses of the
type TYPE. Return 0 on success, -1 on failure. */
-int
-i386_remove_watchpoint (CORE_ADDR addr, int len, int type)
+static int
+i386_remove_watchpoint (CORE_ADDR addr, int len, int type,
+ struct expression *cond)
{
+ struct i386_debug_reg_state *state
+ = i386_debug_reg_state (ptid_get_pid (inferior_ptid));
int retval;
+ /* Work on a local copy of the debug registers, and on success,
+ commit the change back to the inferior. */
+ struct i386_debug_reg_state local_state = *state;
if (((len != 1 && len !=2 && len !=4) && !(TARGET_HAS_DR_LEN_8 && len == 8))
|| addr % len != 0)
- retval = i386_handle_nonaligned_watchpoint (WP_REMOVE, addr, len, type);
+ retval = i386_handle_nonaligned_watchpoint (&local_state,
+ WP_REMOVE, addr, len, type);
else
{
unsigned len_rw = i386_length_and_rw_bits (len, type);
- retval = i386_remove_aligned_watchpoint (addr, len_rw);
+ retval = i386_remove_aligned_watchpoint (&local_state,
+ addr, len_rw);
}
+ if (retval == 0)
+ i386_update_inferior_debug_regs (&local_state);
+
if (maint_show_dr)
- i386_show_dr ("remove_watchpoint", addr, len, type);
+ i386_show_dr (state, "remove_watchpoint", addr, len, type);
return retval;
}
/* Return non-zero if we can watch a memory region that starts at
address ADDR and whose length is LEN bytes. */
-int
+static int
i386_region_ok_for_watchpoint (CORE_ADDR addr, int len)
{
+ struct i386_debug_reg_state *state
+ = i386_debug_reg_state (ptid_get_pid (inferior_ptid));
int nregs;
/* Compute how many aligned watchpoints we would need to cover this
region. */
- nregs = i386_handle_nonaligned_watchpoint (WP_COUNT, addr, len, hw_write);
+ nregs = i386_handle_nonaligned_watchpoint (state,
+ WP_COUNT, addr, len, hw_write);
return nregs <= DR_NADDR ? 1 : 0;
}
-/* If the inferior has some watchpoint that triggered, return the
- address associated with that watchpoint. Otherwise, return zero. */
+/* If the inferior has some watchpoint that triggered, set the
+ address associated with that watchpoint and return non-zero.
+ Otherwise, return zero. */
-CORE_ADDR
-i386_stopped_data_address (void)
+static int
+i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
{
+ struct i386_debug_reg_state *state
+ = i386_debug_reg_state (ptid_get_pid (inferior_ptid));
CORE_ADDR addr = 0;
int i;
-
- dr_status_mirror = I386_DR_LOW_GET_STATUS ();
+ int rc = 0;
+ /* The current thread's DR_STATUS. We always need to read this to
+ check whether some watchpoint caused the trap. */
+ unsigned status;
+ /* We need DR_CONTROL as well, but only iff DR_STATUS indicates a
+ data breakpoint trap. Only fetch it when necessary, to avoid an
+ unnecessary extra syscall when no watchpoint triggered. */
+ int control_p = 0;
+ unsigned control = 0;
+
+ /* In non-stop/async, threads can be running while we change the
+ STATE (and friends). Say, we set a watchpoint, and let threads
+ resume. Now, say you delete the watchpoint, or add/remove
+ watchpoints such that STATE changes while threads are running.
+ On targets that support non-stop, inserting/deleting watchpoints
+ updates the STATE only. It does not update the real thread's
+ debug registers; that's only done prior to resume. Instead, if
+ threads are running when the mirror changes, a temporary and
+ transparent stop on all threads is forced so they can get their
+ copy of the debug registers updated on re-resume. Now, say,
+ a thread hit a watchpoint before having been updated with the new
+ STATE contents, and we haven't yet handled the corresponding
+ SIGTRAP. If we trusted STATE below, we'd mistake the real
+ trapped address (from the last time we had updated debug
+ registers in the thread) with whatever was currently in STATE.
+ So to fix this, STATE always represents intention, what we _want_
+ threads to have in debug registers. To get at the address and
+ cause of the trap, we need to read the state the thread still has
+ in its debug registers.
+
+ In sum, always get the current debug register values the current
+ thread has, instead of trusting the global mirror. If the thread
+ was running when we last changed watchpoints, the mirror no
+ longer represents what was set in this thread's debug
+ registers. */
+ status = i386_dr_low.get_status ();
ALL_DEBUG_REGISTERS(i)
{
- if (I386_DR_WATCH_HIT (i)
- /* This second condition makes sure DRi is set up for a data
- watchpoint, not a hardware breakpoint. The reason is
- that GDB doesn't call the target_stopped_data_address
- method except for data watchpoints. In other words, I'm
- being paranoiac. */
- && I386_DR_GET_RW_LEN (i) != 0)
+ if (!I386_DR_WATCH_HIT (status, i))
+ continue;
+
+ if (!control_p)
+ {
+ control = i386_dr_low.get_control ();
+ control_p = 1;
+ }
+
+ /* This second condition makes sure DRi is set up for a data
+ watchpoint, not a hardware breakpoint. The reason is that
+ GDB doesn't call the target_stopped_data_address method
+ except for data watchpoints. In other words, I'm being
+ paranoiac. */
+ if (I386_DR_GET_RW_LEN (control, i) != 0)
{
- addr = dr_mirror[i];
+ addr = i386_dr_low.get_addr (i);
+ rc = 1;
if (maint_show_dr)
- i386_show_dr ("watchpoint_hit", addr, -1, hw_write);
+ i386_show_dr (state, "watchpoint_hit", addr, -1, hw_write);
}
}
if (maint_show_dr && addr == 0)
- i386_show_dr ("stopped_data_addr", 0, 0, hw_write);
+ i386_show_dr (state, "stopped_data_addr", 0, 0, hw_write);
- return addr;
+ if (rc)
+ *addr_p = addr;
+ return rc;
}
-/* Return non-zero if the inferior has some break/watchpoint that
- triggered. */
-
-int
-i386_stopped_by_hwbp (void)
+static int
+i386_stopped_by_watchpoint (struct target_ops *ops)
{
- int i;
-
- dr_status_mirror = I386_DR_LOW_GET_STATUS ();
- if (maint_show_dr)
- i386_show_dr ("stopped_by_hwbp", 0, 0, hw_execute);
-
- ALL_DEBUG_REGISTERS(i)
- {
- if (I386_DR_WATCH_HIT (i))
- return 1;
- }
-
- return 0;
+ CORE_ADDR addr = 0;
+ return i386_stopped_data_address (ops, &addr);
}
-/* Insert a hardware-assisted breakpoint at address ADDR. SHADOW is
- unused. Return 0 on success, EBUSY on failure. */
-int
-i386_insert_hw_breakpoint (CORE_ADDR addr, void *shadow)
+/* Insert a hardware-assisted breakpoint at BP_TGT->placed_address.
+ Return 0 on success, EBUSY on failure. */
+static int
+i386_insert_hw_breakpoint (struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
+ struct i386_debug_reg_state *state
+ = i386_debug_reg_state (ptid_get_pid (inferior_ptid));
unsigned len_rw = i386_length_and_rw_bits (1, hw_execute);
- int retval = i386_insert_aligned_watchpoint (addr, len_rw) ? EBUSY : 0;
+ CORE_ADDR addr = bp_tgt->placed_address;
+ /* Work on a local copy of the debug registers, and on success,
+ commit the change back to the inferior. */
+ struct i386_debug_reg_state local_state = *state;
+ int retval = i386_insert_aligned_watchpoint (&local_state,
+ addr, len_rw) ? EBUSY : 0;
+
+ if (retval == 0)
+ i386_update_inferior_debug_regs (&local_state);
if (maint_show_dr)
- i386_show_dr ("insert_hwbp", addr, 1, hw_execute);
+ i386_show_dr (state, "insert_hwbp", addr, 1, hw_execute);
return retval;
}
-/* Remove a hardware-assisted breakpoint at address ADDR. SHADOW is
- unused. Return 0 on success, -1 on failure. */
+/* Remove a hardware-assisted breakpoint at BP_TGT->placed_address.
+ Return 0 on success, -1 on failure. */
-int
-i386_remove_hw_breakpoint (CORE_ADDR addr, void *shadow)
+static int
+i386_remove_hw_breakpoint (struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
+ struct i386_debug_reg_state *state
+ = i386_debug_reg_state (ptid_get_pid (inferior_ptid));
unsigned len_rw = i386_length_and_rw_bits (1, hw_execute);
- int retval = i386_remove_aligned_watchpoint (addr, len_rw);
+ CORE_ADDR addr = bp_tgt->placed_address;
+ /* Work on a local copy of the debug registers, and on success,
+ commit the change back to the inferior. */
+ struct i386_debug_reg_state local_state = *state;
+ int retval = i386_remove_aligned_watchpoint (&local_state,
+ addr, len_rw);
+
+ if (retval == 0)
+ i386_update_inferior_debug_regs (&local_state);
if (maint_show_dr)
- i386_show_dr ("remove_hwbp", addr, 1, hw_execute);
+ i386_show_dr (state, "remove_hwbp", addr, 1, hw_execute);
return retval;
}
-#endif /* I386_USE_GENERIC_WATCHPOINTS */
-\f
+/* Returns the number of hardware watchpoints of type TYPE that we can
+ set. Value is positive if we can set CNT watchpoints, zero if
+ setting watchpoints of type TYPE is not supported, and negative if
+ CNT is more than the maximum number of watchpoints of type TYPE
+ that we can support. TYPE is one of bp_hardware_watchpoint,
+ bp_read_watchpoint, bp_write_watchpoint, or bp_hardware_breakpoint.
+ CNT is the number of such watchpoints used so far (including this
+ one). OTHERTYPE is non-zero if other types of watchpoints are
+ currently enabled.
+
+ We always return 1 here because we don't have enough information
+ about possible overlap of addresses that they want to watch. As an
+ extreme example, consider the case where all the watchpoints watch
+ the same address and the same region length: then we can handle a
+ virtually unlimited number of watchpoints, due to debug register
+ sharing implemented via reference counts in i386-nat.c. */
-/* Provide a prototype to silence -Wmissing-prototypes. */
-void _initialize_i386_nat (void);
+static int
+i386_can_use_hw_breakpoint (int type, int cnt, int othertype)
+{
+ return 1;
+}
-void
-_initialize_i386_nat (void)
+static void
+add_show_debug_regs_command (void)
{
-#ifdef I386_USE_GENERIC_WATCHPOINTS
/* A maintenance command to enable printing the internal DRi mirror
variables. */
- add_set_cmd ("show-debug-regs", class_maintenance,
- var_boolean, (char *) &maint_show_dr,
- "\
-Set whether to show variables that mirror the x86 debug registers.\n\
+ add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
+ &maint_show_dr, _("\
+Set whether to show variables that mirror the x86 debug registers."), _("\
+Show whether to show variables that mirror the x86 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.", &maintenancelist);
-#endif
+triggers a breakpoint or watchpoint."),
+ NULL,
+ NULL,
+ &maintenance_set_cmdlist,
+ &maintenance_show_cmdlist);
+}
+
+/* There are only two global functions left. */
+
+void
+i386_use_watchpoints (struct target_ops *t)
+{
+ /* After a watchpoint trap, the PC points to the instruction after the
+ one that caused the trap. Therefore we don't need to step over it.
+ But we do need to reset the status register to avoid another trap. */
+ t->to_have_continuable_watchpoint = 1;
+
+ t->to_can_use_hw_breakpoint = i386_can_use_hw_breakpoint;
+ t->to_region_ok_for_hw_watchpoint = i386_region_ok_for_watchpoint;
+ t->to_stopped_by_watchpoint = i386_stopped_by_watchpoint;
+ t->to_stopped_data_address = i386_stopped_data_address;
+ t->to_insert_watchpoint = i386_insert_watchpoint;
+ t->to_remove_watchpoint = i386_remove_watchpoint;
+ t->to_insert_hw_breakpoint = i386_insert_hw_breakpoint;
+ t->to_remove_hw_breakpoint = i386_remove_hw_breakpoint;
+}
+
+void
+i386_set_debug_register_length (int len)
+{
+ /* This function should be called only once for each native target. */
+ gdb_assert (i386_dr_low.debug_register_length == 0);
+ gdb_assert (len == 4 || len == 8);
+ i386_dr_low.debug_register_length = len;
+ add_show_debug_regs_command ();
}
projects / deliverable / binutils-gdb.git / blobdiff