| 1 | /* Misc. low level support for i386. |
| 2 | |
| 3 | Copyright (C) 2009-2014 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | /* Support for hardware watchpoints and breakpoints using the i386 |
| 21 | debug registers. |
| 22 | |
| 23 | This provides several functions for inserting and removing |
| 24 | hardware-assisted breakpoints and watchpoints, testing if one or |
| 25 | more of the watchpoints triggered and at what address, checking |
| 26 | whether a given region can be watched, etc. |
| 27 | |
| 28 | The functions below implement debug registers sharing by reference |
| 29 | counts, and allow to watch regions up to 16 bytes long |
| 30 | (32 bytes on 64 bit hosts). */ |
| 31 | |
| 32 | |
| 33 | /* Debug registers' indices. */ |
| 34 | #define DR_FIRSTADDR 0 |
| 35 | #define DR_LASTADDR 3 |
| 36 | #define DR_NADDR 4 /* The number of debug address registers. */ |
| 37 | #define DR_STATUS 6 |
| 38 | #define DR_CONTROL 7 |
| 39 | |
| 40 | /* Global state needed to track h/w watchpoints. */ |
| 41 | |
| 42 | struct i386_debug_reg_state |
| 43 | { |
| 44 | /* Mirror the inferior's DRi registers. We keep the status and |
| 45 | control registers separated because they don't hold addresses. |
| 46 | Note that since we can change these mirrors while threads are |
| 47 | running, we never trust them to explain a cause of a trap. |
| 48 | For that, we need to peek directly in the inferior registers. */ |
| 49 | CORE_ADDR dr_mirror[DR_NADDR]; |
| 50 | unsigned dr_status_mirror, dr_control_mirror; |
| 51 | |
| 52 | /* Reference counts for each debug register. */ |
| 53 | int dr_ref_count[DR_NADDR]; |
| 54 | }; |
| 55 | |
| 56 | /* Initialize STATE. */ |
| 57 | extern void i386_low_init_dregs (struct i386_debug_reg_state *state); |
| 58 | |
| 59 | /* Insert a watchpoint to watch a memory region which starts at |
| 60 | address ADDR and whose length is LEN bytes. Watch memory accesses |
| 61 | of the type TYPE_FROM_PACKET. Return 0 on success, -1 on failure. */ |
| 62 | extern int i386_low_insert_watchpoint (struct i386_debug_reg_state *state, |
| 63 | char type_from_packet, CORE_ADDR addr, |
| 64 | int len); |
| 65 | |
| 66 | /* Remove a watchpoint that watched the memory region which starts at |
| 67 | address ADDR, whose length is LEN bytes, and for accesses of the |
| 68 | type TYPE_FROM_PACKET. Return 0 on success, -1 on failure. */ |
| 69 | extern int i386_low_remove_watchpoint (struct i386_debug_reg_state *state, |
| 70 | char type_from_packet, CORE_ADDR addr, |
| 71 | int len); |
| 72 | |
| 73 | /* Return non-zero if we can watch a memory region that starts at |
| 74 | address ADDR and whose length is LEN bytes. */ |
| 75 | extern int i386_low_region_ok_for_watchpoint (struct i386_debug_reg_state *state, |
| 76 | CORE_ADDR addr, int len); |
| 77 | |
| 78 | /* If the inferior has some break/watchpoint that triggered, set the |
| 79 | address associated with that break/watchpoint and return true. |
| 80 | Otherwise, return false. */ |
| 81 | extern int i386_low_stopped_data_address (struct i386_debug_reg_state *state, |
| 82 | CORE_ADDR *addr_p); |
| 83 | |
| 84 | /* Return true if the inferior has some watchpoint that triggered. |
| 85 | Otherwise return false. */ |
| 86 | extern int i386_low_stopped_by_watchpoint (struct i386_debug_reg_state *state); |
| 87 | \f |
| 88 | /* Each target needs to provide several low-level functions |
| 89 | that will be called to insert watchpoints and hardware breakpoints |
| 90 | into the inferior, remove them, and check their status. These |
| 91 | functions are: |
| 92 | |
| 93 | i386_dr_low_set_control -- set the debug control (DR7) |
| 94 | register to a given value |
| 95 | |
| 96 | i386_dr_low_set_addr -- put an address into one debug register |
| 97 | |
| 98 | i386_dr_low_get_status -- return the value of the debug |
| 99 | status (DR6) register. |
| 100 | */ |
| 101 | |
| 102 | /* Update the inferior's debug register REGNUM from STATE. */ |
| 103 | extern void i386_dr_low_set_addr (const struct i386_debug_reg_state *state, |
| 104 | int regnum); |
| 105 | |
| 106 | /* Return the inferior's debug register REGNUM. */ |
| 107 | extern CORE_ADDR i386_dr_low_get_addr (int regnum); |
| 108 | |
| 109 | /* Update the inferior's DR7 debug control register from STATE. */ |
| 110 | extern void i386_dr_low_set_control (const struct i386_debug_reg_state *state); |
| 111 | |
| 112 | /* Return the value of the inferior's DR7 debug control register. */ |
| 113 | extern unsigned i386_dr_low_get_control (void); |
| 114 | |
| 115 | /* Return the value of the inferior's DR6 debug status register. */ |
| 116 | extern unsigned i386_dr_low_get_status (void); |