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- /* Native-dependent code for AArch64.
- Copyright (C) 2011-2022 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 "gdbarch.h"
- #include "inferior.h"
- #include "cli/cli-cmds.h"
- #include "aarch64-nat.h"
- #include <unordered_map>
- /* 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, aarch64_debug_reg_state>
- aarch64_debug_process_state;
- /* See aarch64-nat.h. */
- struct aarch64_debug_reg_state *
- aarch64_lookup_debug_reg_state (pid_t pid)
- {
- auto it = aarch64_debug_process_state.find (pid);
- if (it != aarch64_debug_process_state.end ())
- return &it->second;
- return nullptr;
- }
- /* See aarch64-nat.h. */
- struct aarch64_debug_reg_state *
- aarch64_get_debug_reg_state (pid_t pid)
- {
- return &aarch64_debug_process_state[pid];
- }
- /* See aarch64-nat.h. */
- void
- aarch64_remove_debug_reg_state (pid_t pid)
- {
- aarch64_debug_process_state.erase (pid);
- }
- /* 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. */
- int
- aarch64_can_use_hw_breakpoint (enum bptype type, int cnt, int othertype)
- {
- if (type == bp_hardware_watchpoint || type == bp_read_watchpoint
- || type == bp_access_watchpoint || type == bp_watchpoint)
- {
- if (aarch64_num_wp_regs == 0)
- return 0;
- }
- else if (type == bp_hardware_breakpoint)
- {
- if (aarch64_num_bp_regs == 0)
- return 0;
- }
- else
- gdb_assert_not_reached ("unexpected breakpoint type");
- /* 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. */
- return 1;
- }
- /* Insert a hardware-assisted breakpoint at BP_TGT->reqstd_address.
- Return 0 on success, -1 on failure. */
- int
- aarch64_insert_hw_breakpoint (struct gdbarch *gdbarch,
- struct bp_target_info *bp_tgt)
- {
- int ret;
- CORE_ADDR addr = bp_tgt->placed_address = bp_tgt->reqstd_address;
- int len;
- const enum target_hw_bp_type type = hw_execute;
- struct aarch64_debug_reg_state *state
- = aarch64_get_debug_reg_state (inferior_ptid.pid ());
- gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);
- if (show_debug_regs)
- gdb_printf (gdb_stdlog,
- "insert_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
- (unsigned long) addr, len);
- ret = aarch64_handle_breakpoint (type, addr, len, 1 /* is_insert */,
- inferior_ptid, state);
- if (show_debug_regs)
- {
- aarch64_show_debug_reg_state (state,
- "insert_hw_breakpoint", addr, len, type);
- }
- return ret;
- }
- /* Remove a hardware-assisted breakpoint at BP_TGT->placed_address.
- Return 0 on success, -1 on failure. */
- int
- aarch64_remove_hw_breakpoint (struct gdbarch *gdbarch,
- struct bp_target_info *bp_tgt)
- {
- int ret;
- CORE_ADDR addr = bp_tgt->placed_address;
- int len = 4;
- const enum target_hw_bp_type type = hw_execute;
- struct aarch64_debug_reg_state *state
- = aarch64_get_debug_reg_state (inferior_ptid.pid ());
- gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);
- if (show_debug_regs)
- gdb_printf (gdb_stdlog,
- "remove_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
- (unsigned long) addr, len);
- ret = aarch64_handle_breakpoint (type, addr, len, 0 /* is_insert */,
- inferior_ptid, state);
- if (show_debug_regs)
- {
- aarch64_show_debug_reg_state (state,
- "remove_hw_watchpoint", addr, len, type);
- }
- return ret;
- }
- /* 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
- aarch64_insert_watchpoint (CORE_ADDR addr, int len, enum target_hw_bp_type type,
- struct expression *cond)
- {
- int ret;
- struct aarch64_debug_reg_state *state
- = aarch64_get_debug_reg_state (inferior_ptid.pid ());
- if (show_debug_regs)
- gdb_printf (gdb_stdlog,
- "insert_watchpoint on entry (addr=0x%08lx, len=%d)\n",
- (unsigned long) addr, len);
- gdb_assert (type != hw_execute);
- ret = aarch64_handle_watchpoint (type, addr, len, 1 /* is_insert */,
- inferior_ptid, state);
- if (show_debug_regs)
- {
- aarch64_show_debug_reg_state (state,
- "insert_watchpoint", addr, len, type);
- }
- return ret;
- }
- /* 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
- aarch64_remove_watchpoint (CORE_ADDR addr, int len, enum target_hw_bp_type type,
- struct expression *cond)
- {
- int ret;
- struct aarch64_debug_reg_state *state
- = aarch64_get_debug_reg_state (inferior_ptid.pid ());
- if (show_debug_regs)
- gdb_printf (gdb_stdlog,
- "remove_watchpoint on entry (addr=0x%08lx, len=%d)\n",
- (unsigned long) addr, len);
- gdb_assert (type != hw_execute);
- ret = aarch64_handle_watchpoint (type, addr, len, 0 /* is_insert */,
- inferior_ptid, state);
- if (show_debug_regs)
- {
- aarch64_show_debug_reg_state (state,
- "remove_watchpoint", addr, len, type);
- }
- return ret;
- }
- /* See aarch64-nat.h. */
- bool
- aarch64_stopped_data_address (const struct aarch64_debug_reg_state *state,
- CORE_ADDR addr_trap, CORE_ADDR *addr_p)
- {
- int i;
- for (i = aarch64_num_wp_regs - 1; i >= 0; --i)
- {
- const unsigned int offset
- = aarch64_watchpoint_offset (state->dr_ctrl_wp[i]);
- const unsigned int len = aarch64_watchpoint_length (state->dr_ctrl_wp[i]);
- const CORE_ADDR addr_watch = state->dr_addr_wp[i] + offset;
- const CORE_ADDR addr_watch_aligned = align_down (state->dr_addr_wp[i], 8);
- const CORE_ADDR addr_orig = state->dr_addr_orig_wp[i];
- if (state->dr_ref_count_wp[i]
- && DR_CONTROL_ENABLED (state->dr_ctrl_wp[i])
- && addr_trap >= addr_watch_aligned
- && addr_trap < addr_watch + len)
- {
- /* ADDR_TRAP reports the first address of the memory range
- accessed by the CPU, regardless of what was the memory
- range watched. Thus, a large CPU access that straddles
- the ADDR_WATCH..ADDR_WATCH+LEN range may result in an
- ADDR_TRAP that is lower than the
- ADDR_WATCH..ADDR_WATCH+LEN range. E.g.:
- addr: | 4 | 5 | 6 | 7 | 8 |
- |---- range watched ----|
- |----------- range accessed ------------|
- In this case, ADDR_TRAP will be 4.
- To match a watchpoint known to GDB core, we must never
- report *ADDR_P outside of any ADDR_WATCH..ADDR_WATCH+LEN
- range. ADDR_WATCH <= ADDR_TRAP < ADDR_ORIG is a false
- positive on kernels older than 4.10. See PR
- external/20207. */
- *addr_p = addr_orig;
- return true;
- }
- }
- return false;
- }
- /* Define AArch64 maintenance commands. */
- 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 AArch64 debug registers."), _("\
- Show whether to show variables that mirror the AArch64 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);
- }
- void
- aarch64_initialize_hw_point ()
- {
- add_show_debug_regs_command ();
- }
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