1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301
|
/* Native-dependent code for x86 (i386 and x86-64).
Copyright (C) 2001-2018 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 "x86-nat.h"
#include "gdbcmd.h"
#include "inferior.h"
/* Support for hardware watchpoints and breakpoints using the x86
debug registers.
This provides several functions for inserting and removing
hardware-assisted breakpoints and watchpoints, testing if one or
more of the watchpoints triggered and at what address, checking
whether a given region can be watched, etc.
The functions below implement debug registers sharing by reference
counts, and allow to watch regions up to 16 bytes long. */
/* Low-level function vector. */
struct x86_dr_low_type x86_dr_low;
/* 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). */
struct x86_process_info
{
/* Linked list. */
struct x86_process_info *next;
/* The process identifier. */
pid_t pid;
/* Copy of x86 hardware debug registers. */
struct x86_debug_reg_state state;
};
static struct x86_process_info *x86_process_list = NULL;
/* Find process data for process PID. */
static struct x86_process_info *
x86_find_process_pid (pid_t pid)
{
struct x86_process_info *proc;
for (proc = x86_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 x86_process_info *
x86_add_process (pid_t pid)
{
struct x86_process_info *proc = XCNEW (struct x86_process_info);
proc->pid = pid;
proc->next = x86_process_list;
x86_process_list = proc;
return proc;
}
/* Get data specific info for process PID, creating it if necessary.
Never returns NULL. */
static struct x86_process_info *
x86_process_info_get (pid_t pid)
{
struct x86_process_info *proc;
proc = x86_find_process_pid (pid);
if (proc == NULL)
proc = x86_add_process (pid);
return proc;
}
/* Get debug registers state for process PID. */
struct x86_debug_reg_state *
x86_debug_reg_state (pid_t pid)
{
return &x86_process_info_get (pid)->state;
}
/* See declaration in x86-nat.h. */
void
x86_forget_process (pid_t pid)
{
struct x86_process_info *proc, **proc_link;
proc = x86_process_list;
proc_link = &x86_process_list;
while (proc != NULL)
{
if (proc->pid == pid)
{
*proc_link = proc->next;
xfree (proc);
return;
}
proc_link = &proc->next;
proc = *proc_link;
}
}
/* Clear the reference counts and forget everything we knew about the
debug registers. */
void
x86_cleanup_dregs (void)
{
/* Starting from scratch has the same effect. */
x86_forget_process (inferior_ptid.pid ());
}
/* 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
x86_insert_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type, struct expression *cond)
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
return x86_dr_insert_watchpoint (state, type, addr, len);
}
/* 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
x86_remove_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type, struct expression *cond)
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
return x86_dr_remove_watchpoint (state, type, addr, len);
}
/* Return non-zero if we can watch a memory region that starts at
address ADDR and whose length is LEN bytes. */
int
x86_region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
return x86_dr_region_ok_for_watchpoint (state, addr, len);
}
/* If the inferior has some break/watchpoint that triggered, set the
address associated with that break/watchpoint and return non-zero.
Otherwise, return zero. */
int
x86_stopped_data_address (CORE_ADDR *addr_p)
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
return x86_dr_stopped_data_address (state, addr_p);
}
/* Return non-zero if the inferior has some watchpoint that triggered.
Otherwise return zero. */
int
x86_stopped_by_watchpoint ()
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
return x86_dr_stopped_by_watchpoint (state);
}
/* Insert a hardware-assisted breakpoint at BP_TGT->reqstd_address.
Return 0 on success, EBUSY on failure. */
int
x86_insert_hw_breakpoint (struct gdbarch *gdbarch, struct bp_target_info *bp_tgt)
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
bp_tgt->placed_address = bp_tgt->reqstd_address;
return x86_dr_insert_watchpoint (state, hw_execute,
bp_tgt->placed_address, 1) ? EBUSY : 0;
}
/* Remove a hardware-assisted breakpoint at BP_TGT->placed_address.
Return 0 on success, -1 on failure. */
int
x86_remove_hw_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
return x86_dr_remove_watchpoint (state, hw_execute,
bp_tgt->placed_address, 1);
}
/* 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 x86-nat.c. */
int
x86_can_use_hw_breakpoint (enum bptype type, int cnt, int othertype)
{
return 1;
}
/* Return non-zero if the inferior has some breakpoint that triggered.
Otherwise return zero. */
int
x86_stopped_by_hw_breakpoint ()
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (inferior_ptid.pid ());
return x86_dr_stopped_by_hw_breakpoint (state);
}
static void
add_show_debug_regs_command (void)
{
/* A maintenance command to enable printing the internal DRi mirror
variables. */
add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
&show_debug_regs, _("\
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."),
NULL,
NULL,
&maintenance_set_cmdlist,
&maintenance_show_cmdlist);
}
/* See x86-nat.h. */
void
x86_set_debug_register_length (int len)
{
/* This function should be called only once for each native target. */
gdb_assert (x86_dr_low.debug_register_length == 0);
gdb_assert (len == 4 || len == 8);
x86_dr_low.debug_register_length = len;
add_show_debug_regs_command ();
}
|