1 /* Debug register code for x86 (i386 and x86-64). 2 3 Copyright (C) 2009-2016 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 #include "break-common.h" /* target_hw_bp_type */ 36 37 /* Low-level function vector. */ 38 39 struct x86_dr_low_type 40 { 41 /* Set the debug control (DR7) register to a given value for 42 all LWPs. May be NULL if the debug control register cannot 43 be set. */ 44 void (*set_control) (unsigned long); 45 46 /* Put an address into one debug register for all LWPs. May 47 be NULL if debug registers cannot be set*/ 48 void (*set_addr) (int, CORE_ADDR); 49 50 /* Return the address in a given debug register of the current 51 LWP. */ 52 CORE_ADDR (*get_addr) (int); 53 54 /* Return the value of the debug status (DR6) register for 55 current LWP. */ 56 unsigned long (*get_status) (void); 57 58 /* Return the value of the debug control (DR7) register for 59 current LWP. */ 60 unsigned long (*get_control) (void); 61 62 /* Number of bytes used for debug registers (4 or 8). */ 63 int debug_register_length; 64 }; 65 66 extern struct x86_dr_low_type x86_dr_low; 67 68 /* Debug registers' indices. */ 69 #define DR_FIRSTADDR 0 70 #define DR_LASTADDR 3 71 #define DR_NADDR 4 /* The number of debug address registers. */ 72 #define DR_STATUS 6 /* Index of debug status register (DR6). */ 73 #define DR_CONTROL 7 /* Index of debug control register (DR7). */ 74 75 /* Global state needed to track h/w watchpoints. */ 76 77 struct x86_debug_reg_state 78 { 79 /* Mirror the inferior's DRi registers. We keep the status and 80 control registers separated because they don't hold addresses. 81 Note that since we can change these mirrors while threads are 82 running, we never trust them to explain a cause of a trap. 83 For that, we need to peek directly in the inferior registers. */ 84 CORE_ADDR dr_mirror[DR_NADDR]; 85 unsigned dr_status_mirror, dr_control_mirror; 86 87 /* Reference counts for each debug address register. */ 88 int dr_ref_count[DR_NADDR]; 89 }; 90 91 /* A macro to loop over all debug address registers. */ 92 #define ALL_DEBUG_ADDRESS_REGISTERS(i) \ 93 for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++) 94 95 /* Return a pointer to the local mirror of the debug registers of 96 process PID. This function must be provided by the client 97 if required. */ 98 extern struct x86_debug_reg_state *x86_debug_reg_state (pid_t pid); 99 100 /* Insert a watchpoint to watch a memory region which starts at 101 address ADDR and whose length is LEN bytes. Watch memory accesses 102 of the type TYPE. Return 0 on success, -1 on failure. */ 103 extern int x86_dr_insert_watchpoint (struct x86_debug_reg_state *state, 104 enum target_hw_bp_type type, 105 CORE_ADDR addr, 106 int len); 107 108 /* Remove a watchpoint that watched the memory region which starts at 109 address ADDR, whose length is LEN bytes, and for accesses of the 110 type TYPE. Return 0 on success, -1 on failure. */ 111 extern int x86_dr_remove_watchpoint (struct x86_debug_reg_state *state, 112 enum target_hw_bp_type type, 113 CORE_ADDR addr, 114 int len); 115 116 /* Return non-zero if we can watch a memory region that starts at 117 address ADDR and whose length is LEN bytes. */ 118 extern int x86_dr_region_ok_for_watchpoint (struct x86_debug_reg_state *state, 119 CORE_ADDR addr, int len); 120 121 /* If the inferior has some break/watchpoint that triggered, set the 122 address associated with that break/watchpoint and return true. 123 Otherwise, return false. */ 124 extern int x86_dr_stopped_data_address (struct x86_debug_reg_state *state, 125 CORE_ADDR *addr_p); 126 127 /* Return true if the inferior has some watchpoint that triggered. 128 Otherwise return false. */ 129 extern int x86_dr_stopped_by_watchpoint (struct x86_debug_reg_state *state); 130 131 #endif /* X86_DREGS_H */ 132