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1 | /* Misc. low level support for i386. |
2 | ||
0b302171 | 3 | Copyright (C) 2009-2012 Free Software Foundation, Inc. |
e6f9de87 DE |
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 | |
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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. */ | |
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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 | ||
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106 | /* Return the inferior's debug register REGNUM. */ |
107 | extern CORE_ADDR i386_dr_low_get_addr (int regnum); | |
108 | ||
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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 | ||
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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); |