1 /* Debug register code for x86 (i386 and x86-64). 2 3 Copyright (C) 2009-2015 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 x86 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 #ifndef X86_DREGS_H 33 #define X86_DREGS_H 1 34 35 /* Forward declaration. */ 36 enum target_hw_bp_type; 37 38 /* Low-level function vector. */ 39 40 struct x86_dr_low_type 41 { 42 /* Set the debug control (DR7) register to a given value for 43 all LWPs. May be NULL if the debug control register cannot 44 be set. */ 45 void (*set_control) (unsigned long); 46 47 /* Put an address into one debug register for all LWPs. May 48 be NULL if debug registers cannot be set*/ 49 void (*set_addr) (int, CORE_ADDR); 50 51 /* Return the address in a given debug register of the current 52 LWP. */ 53 CORE_ADDR (*get_addr) (int); 54 55 /* Return the value of the debug status (DR6) register for 56 current LWP. */ 57 unsigned long (*get_status) (void); 58 59 /* Return the value of the debug control (DR7) register for 60 current LWP. */ 61 unsigned long (*get_control) (void); 62 63 /* Number of bytes used for debug registers (4 or 8). */ 64 int debug_register_length; 65 }; 66 67 extern struct x86_dr_low_type x86_dr_low; 68 69 /* Debug registers' indices. */ 70 #define DR_FIRSTADDR 0 71 #define DR_LASTADDR 3 72 #define DR_NADDR 4 /* The number of debug address registers. */ 73 #define DR_STATUS 6 /* Index of debug status register (DR6). */ 74 #define DR_CONTROL 7 /* Index of debug control register (DR7). */ 75 76 /* Global state needed to track h/w watchpoints. */ 77 78 struct x86_debug_reg_state 79 { 80 /* Mirror the inferior's DRi registers. We keep the status and 81 control registers separated because they don't hold addresses. 82 Note that since we can change these mirrors while threads are 83 running, we never trust them to explain a cause of a trap. 84 For that, we need to peek directly in the inferior registers. */ 85 CORE_ADDR dr_mirror[DR_NADDR]; 86 unsigned dr_status_mirror, dr_control_mirror; 87 88 /* Reference counts for each debug address register. */ 89 int dr_ref_count[DR_NADDR]; 90 }; 91 92 /* A macro to loop over all debug address registers. */ 93 #define ALL_DEBUG_ADDRESS_REGISTERS(i) \ 94 for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++) 95 96 /* Insert a watchpoint to watch a memory region which starts at 97 address ADDR and whose length is LEN bytes. Watch memory accesses 98 of the type TYPE. Return 0 on success, -1 on failure. */ 99 extern int x86_dr_insert_watchpoint (struct x86_debug_reg_state *state, 100 enum target_hw_bp_type type, 101 CORE_ADDR addr, 102 int len); 103 104 /* Remove a watchpoint that watched the memory region which starts at 105 address ADDR, whose length is LEN bytes, and for accesses of the 106 type TYPE. Return 0 on success, -1 on failure. */ 107 extern int x86_dr_remove_watchpoint (struct x86_debug_reg_state *state, 108 enum target_hw_bp_type type, 109 CORE_ADDR addr, 110 int len); 111 112 /* Return non-zero if we can watch a memory region that starts at 113 address ADDR and whose length is LEN bytes. */ 114 extern int x86_dr_region_ok_for_watchpoint (struct x86_debug_reg_state *state, 115 CORE_ADDR addr, int len); 116 117 /* If the inferior has some break/watchpoint that triggered, set the 118 address associated with that break/watchpoint and return true. 119 Otherwise, return false. */ 120 extern int x86_dr_stopped_data_address (struct x86_debug_reg_state *state, 121 CORE_ADDR *addr_p); 122 123 /* Return true if the inferior has some watchpoint that triggered. 124 Otherwise return false. */ 125 extern int x86_dr_stopped_by_watchpoint (struct x86_debug_reg_state *state); 126 127 #endif /* X86_DREGS_H */ 128