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1 | #ifndef _ASM_GENERIC_HW_BREAKPOINT_H |
2 | #define _ASM_GENERIC_HW_BREAKPOINT_H | |
3 | ||
4 | #ifndef __ARCH_HW_BREAKPOINT_H | |
5 | #error "Please don't include this file directly" | |
6 | #endif | |
7 | ||
8 | #ifdef __KERNEL__ | |
9 | #include <linux/list.h> | |
10 | #include <linux/types.h> | |
11 | #include <linux/kallsyms.h> | |
12 | ||
13 | /** | |
14 | * struct hw_breakpoint - unified kernel/user-space hardware breakpoint | |
15 | * @triggered: callback invoked after target address access | |
16 | * @info: arch-specific breakpoint info (address, length, and type) | |
17 | * | |
18 | * %hw_breakpoint structures are the kernel's way of representing | |
19 | * hardware breakpoints. These are data breakpoints | |
20 | * (also known as "watchpoints", triggered on data access), and the breakpoint's | |
21 | * target address can be located in either kernel space or user space. | |
22 | * | |
23 | * The breakpoint's address, length, and type are highly | |
24 | * architecture-specific. The values are encoded in the @info field; you | |
25 | * specify them when registering the breakpoint. To examine the encoded | |
26 | * values use hw_breakpoint_get_{kaddress,uaddress,len,type}(), declared | |
27 | * below. | |
28 | * | |
29 | * The address is specified as a regular kernel pointer (for kernel-space | |
30 | * breakponts) or as an %__user pointer (for user-space breakpoints). | |
31 | * With register_user_hw_breakpoint(), the address must refer to a | |
32 | * location in user space. The breakpoint will be active only while the | |
33 | * requested task is running. Conversely with | |
34 | * register_kernel_hw_breakpoint(), the address must refer to a location | |
35 | * in kernel space, and the breakpoint will be active on all CPUs | |
36 | * regardless of the current task. | |
37 | * | |
38 | * The length is the breakpoint's extent in bytes, which is subject to | |
39 | * certain limitations. include/asm/hw_breakpoint.h contains macros | |
40 | * defining the available lengths for a specific architecture. Note that | |
41 | * the address's alignment must match the length. The breakpoint will | |
42 | * catch accesses to any byte in the range from address to address + | |
43 | * (length - 1). | |
44 | * | |
45 | * The breakpoint's type indicates the sort of access that will cause it | |
46 | * to trigger. Possible values may include: | |
47 | * | |
48 | * %HW_BREAKPOINT_RW (triggered on read or write access), | |
49 | * %HW_BREAKPOINT_WRITE (triggered on write access), and | |
50 | * %HW_BREAKPOINT_READ (triggered on read access). | |
51 | * | |
52 | * Appropriate macros are defined in include/asm/hw_breakpoint.h; not all | |
53 | * possibilities are available on all architectures. Execute breakpoints | |
54 | * must have length equal to the special value %HW_BREAKPOINT_LEN_EXECUTE. | |
55 | * | |
56 | * When a breakpoint gets hit, the @triggered callback is | |
57 | * invoked in_interrupt with a pointer to the %hw_breakpoint structure and the | |
58 | * processor registers. | |
59 | * Data breakpoints occur after the memory access has taken place. | |
60 | * Breakpoints are disabled during execution @triggered, to avoid | |
61 | * recursive traps and allow unhindered access to breakpointed memory. | |
62 | * | |
63 | * This sample code sets a breakpoint on pid_max and registers a callback | |
64 | * function for writes to that variable. Note that it is not portable | |
65 | * as written, because not all architectures support HW_BREAKPOINT_LEN_4. | |
66 | * | |
67 | * ---------------------------------------------------------------------- | |
68 | * | |
69 | * #include <asm/hw_breakpoint.h> | |
70 | * | |
71 | * struct hw_breakpoint my_bp; | |
72 | * | |
73 | * static void my_triggered(struct hw_breakpoint *bp, struct pt_regs *regs) | |
74 | * { | |
75 | * printk(KERN_DEBUG "Inside triggered routine of breakpoint exception\n"); | |
76 | * dump_stack(); | |
77 | * .......<more debugging output>........ | |
78 | * } | |
79 | * | |
80 | * static struct hw_breakpoint my_bp; | |
81 | * | |
82 | * static int init_module(void) | |
83 | * { | |
84 | * ..........<do anything>............ | |
85 | * my_bp.info.type = HW_BREAKPOINT_WRITE; | |
86 | * my_bp.info.len = HW_BREAKPOINT_LEN_4; | |
87 | * | |
88 | * my_bp.installed = (void *)my_bp_installed; | |
89 | * | |
90 | * rc = register_kernel_hw_breakpoint(&my_bp); | |
91 | * ..........<do anything>............ | |
92 | * } | |
93 | * | |
94 | * static void cleanup_module(void) | |
95 | * { | |
96 | * ..........<do anything>............ | |
97 | * unregister_kernel_hw_breakpoint(&my_bp); | |
98 | * ..........<do anything>............ | |
99 | * } | |
100 | * | |
101 | * ---------------------------------------------------------------------- | |
102 | */ | |
103 | struct hw_breakpoint { | |
104 | void (*triggered)(struct hw_breakpoint *, struct pt_regs *); | |
105 | struct arch_hw_breakpoint info; | |
106 | }; | |
107 | ||
108 | /* | |
109 | * len and type values are defined in include/asm/hw_breakpoint.h. | |
110 | * Available values vary according to the architecture. On i386 the | |
111 | * possibilities are: | |
112 | * | |
113 | * HW_BREAKPOINT_LEN_1 | |
114 | * HW_BREAKPOINT_LEN_2 | |
115 | * HW_BREAKPOINT_LEN_4 | |
116 | * HW_BREAKPOINT_RW | |
117 | * HW_BREAKPOINT_READ | |
118 | * | |
119 | * On other architectures HW_BREAKPOINT_LEN_8 may be available, and the | |
120 | * 1-, 2-, and 4-byte lengths may be unavailable. There also may be | |
121 | * HW_BREAKPOINT_WRITE. You can use #ifdef to check at compile time. | |
122 | */ | |
123 | ||
124 | extern int register_user_hw_breakpoint(struct task_struct *tsk, | |
125 | struct hw_breakpoint *bp); | |
126 | extern int modify_user_hw_breakpoint(struct task_struct *tsk, | |
127 | struct hw_breakpoint *bp); | |
128 | extern void unregister_user_hw_breakpoint(struct task_struct *tsk, | |
129 | struct hw_breakpoint *bp); | |
130 | /* | |
131 | * Kernel breakpoints are not associated with any particular thread. | |
132 | */ | |
133 | extern int register_kernel_hw_breakpoint(struct hw_breakpoint *bp); | |
134 | extern void unregister_kernel_hw_breakpoint(struct hw_breakpoint *bp); | |
135 | ||
136 | extern unsigned int hbp_kernel_pos; | |
137 | ||
138 | #endif /* __KERNEL__ */ | |
139 | #endif /* _ASM_GENERIC_HW_BREAKPOINT_H */ |