123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243 |
- /* Native-dependent code for x86 (i386 and x86-64).
- Copyright (C) 2001-2022 Free Software Foundation, Inc.
- This file is part of GDB.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- #include "defs.h"
- #include "x86-nat.h"
- #include "gdbcmd.h"
- #include "inferior.h"
- #include <unordered_map>
- /* 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;
- /* Hash table storing 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). */
- static std::unordered_map<pid_t,
- struct x86_debug_reg_state> x86_debug_process_state;
- /* See x86-nat.h. */
- struct x86_debug_reg_state *
- x86_lookup_debug_reg_state (pid_t pid)
- {
- auto it = x86_debug_process_state.find (pid);
- if (it != x86_debug_process_state.end ())
- return &it->second;
- return nullptr;
- }
- /* Get debug registers state for process PID. */
- struct x86_debug_reg_state *
- x86_debug_reg_state (pid_t pid)
- {
- return &x86_debug_process_state[pid];
- }
- /* See declaration in x86-nat.h. */
- void
- x86_forget_process (pid_t pid)
- {
- x86_debug_process_state.erase (pid);
- }
- /* 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 ();
- }
|