1 /*
2 * This provides the callbacks and functions that KGDB needs to share between
3 * the core, I/O and arch-specific portions.
4 *
5 * Author: Amit Kale <amitkale@linsyssoft.com> and
6 * Tom Rini <trini@kernel.crashing.org>
7 *
8 * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc.
9 * This file is licensed under the terms of the GNU General Public License
10 * version 2. This program is licensed "as is" without any warranty of any
11 * kind, whether express or implied.
12 */
13 #ifndef _KGDB_H_
14 #define _KGDB_H_
15
16 #include <linux/linkage.h>
17 #include <linux/init.h>
18 #include <linux/atomic.h>
19 #include <linux/kprobes.h>
20 #ifdef CONFIG_HAVE_ARCH_KGDB
21 #include <asm/kgdb.h>
22 #endif
23
24 #ifdef CONFIG_KGDB
25 struct pt_regs;
26
27 /**
28 * kgdb_skipexception - (optional) exit kgdb_handle_exception early
29 * @exception: Exception vector number
30 * @regs: Current &struct pt_regs.
31 *
32 * On some architectures it is required to skip a breakpoint
33 * exception when it occurs after a breakpoint has been removed.
34 * This can be implemented in the architecture specific portion of kgdb.
35 */
36 extern int kgdb_skipexception(int exception, struct pt_regs *regs);
37
38 struct tasklet_struct;
39 struct task_struct;
40 struct uart_port;
41
42 /**
43 * kgdb_breakpoint - compiled in breakpoint
44 *
45 * This will be implemented as a static inline per architecture. This
46 * function is called by the kgdb core to execute an architecture
47 * specific trap to cause kgdb to enter the exception processing.
48 *
49 */
50 void kgdb_breakpoint(void);
51
52 extern int kgdb_connected;
53 extern int kgdb_io_module_registered;
54
55 extern atomic_t kgdb_setting_breakpoint;
56 extern atomic_t kgdb_cpu_doing_single_step;
57
58 extern struct task_struct *kgdb_usethread;
59 extern struct task_struct *kgdb_contthread;
60
61 enum kgdb_bptype {
62 BP_BREAKPOINT = 0,
63 BP_HARDWARE_BREAKPOINT,
64 BP_WRITE_WATCHPOINT,
65 BP_READ_WATCHPOINT,
66 BP_ACCESS_WATCHPOINT,
67 BP_POKE_BREAKPOINT,
68 };
69
70 enum kgdb_bpstate {
71 BP_UNDEFINED = 0,
72 BP_REMOVED,
73 BP_SET,
74 BP_ACTIVE
75 };
76
77 struct kgdb_bkpt {
78 unsigned long bpt_addr;
79 unsigned char saved_instr[BREAK_INSTR_SIZE];
80 enum kgdb_bptype type;
81 enum kgdb_bpstate state;
82 };
83
84 struct dbg_reg_def_t {
85 char *name;
86 int size;
87 int offset;
88 };
89
90 #ifndef DBG_MAX_REG_NUM
91 #define DBG_MAX_REG_NUM 0
92 #else
93 extern struct dbg_reg_def_t dbg_reg_def[];
94 extern char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs);
95 extern int dbg_set_reg(int regno, void *mem, struct pt_regs *regs);
96 #endif
97 #ifndef KGDB_MAX_BREAKPOINTS
98 # define KGDB_MAX_BREAKPOINTS 1000
99 #endif
100
101 #define KGDB_HW_BREAKPOINT 1
102
103 /*
104 * Functions each KGDB-supporting architecture must provide:
105 */
106
107 /**
108 * kgdb_arch_init - Perform any architecture specific initialization.
109 *
110 * This function will handle the initialization of any architecture
111 * specific callbacks.
112 */
113 extern int kgdb_arch_init(void);
114
115 /**
116 * kgdb_arch_exit - Perform any architecture specific uninitalization.
117 *
118 * This function will handle the uninitalization of any architecture
119 * specific callbacks, for dynamic registration and unregistration.
120 */
121 extern void kgdb_arch_exit(void);
122
123 /**
124 * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
125 * @gdb_regs: A pointer to hold the registers in the order GDB wants.
126 * @regs: The &struct pt_regs of the current process.
127 *
128 * Convert the pt_regs in @regs into the format for registers that
129 * GDB expects, stored in @gdb_regs.
130 */
131 extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
132
133 /**
134 * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
135 * @gdb_regs: A pointer to hold the registers in the order GDB wants.
136 * @p: The &struct task_struct of the desired process.
137 *
138 * Convert the register values of the sleeping process in @p to
139 * the format that GDB expects.
140 * This function is called when kgdb does not have access to the
141 * &struct pt_regs and therefore it should fill the gdb registers
142 * @gdb_regs with what has been saved in &struct thread_struct
143 * thread field during switch_to.
144 */
145 extern void
146 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
147
148 /**
149 * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
150 * @gdb_regs: A pointer to hold the registers we've received from GDB.
151 * @regs: A pointer to a &struct pt_regs to hold these values in.
152 *
153 * Convert the GDB regs in @gdb_regs into the pt_regs, and store them
154 * in @regs.
155 */
156 extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
157
158 /**
159 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
160 * @vector: The error vector of the exception that happened.
161 * @signo: The signal number of the exception that happened.
162 * @err_code: The error code of the exception that happened.
163 * @remcom_in_buffer: The buffer of the packet we have read.
164 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
165 * @regs: The &struct pt_regs of the current process.
166 *
167 * This function MUST handle the 'c' and 's' command packets,
168 * as well packets to set / remove a hardware breakpoint, if used.
169 * If there are additional packets which the hardware needs to handle,
170 * they are handled here. The code should return -1 if it wants to
171 * process more packets, and a %0 or %1 if it wants to exit from the
172 * kgdb callback.
173 */
174 extern int
175 kgdb_arch_handle_exception(int vector, int signo, int err_code,
176 char *remcom_in_buffer,
177 char *remcom_out_buffer,
178 struct pt_regs *regs);
179
180 /**
181 * kgdb_arch_handle_qxfer_pkt - Handle architecture specific GDB XML
182 * packets.
183 * @remcom_in_buffer: The buffer of the packet we have read.
184 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
185 */
186
187 extern void
188 kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
189 char *remcom_out_buffer);
190
191 /**
192 * kgdb_call_nmi_hook - Call kgdb_nmicallback() on the current CPU
193 * @ignored: This parameter is only here to match the prototype.
194 *
195 * If you're using the default implementation of kgdb_roundup_cpus()
196 * this function will be called per CPU. If you don't implement
197 * kgdb_call_nmi_hook() a default will be used.
198 */
199
200 extern void kgdb_call_nmi_hook(void *ignored);
201
202 /**
203 * kgdb_roundup_cpus - Get other CPUs into a holding pattern
204 *
205 * On SMP systems, we need to get the attention of the other CPUs
206 * and get them into a known state. This should do what is needed
207 * to get the other CPUs to call kgdb_wait(). Note that on some arches,
208 * the NMI approach is not used for rounding up all the CPUs. Normally
209 * those architectures can just not implement this and get the default.
210 *
211 * On non-SMP systems, this is not called.
212 */
213 extern void kgdb_roundup_cpus(void);
214
215 /**
216 * kgdb_arch_set_pc - Generic call back to the program counter
217 * @regs: Current &struct pt_regs.
218 * @pc: The new value for the program counter
219 *
220 * This function handles updating the program counter and requires an
221 * architecture specific implementation.
222 */
223 extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc);
224
225
226 /* Optional functions. */
227 extern int kgdb_validate_break_address(unsigned long addr);
228 extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);
229 extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);
230
231 /**
232 * kgdb_arch_late - Perform any architecture specific initialization.
233 *
234 * This function will handle the late initialization of any
235 * architecture specific callbacks. This is an optional function for
236 * handling things like late initialization of hw breakpoints. The
237 * default implementation does nothing.
238 */
239 extern void kgdb_arch_late(void);
240
241
242 /**
243 * struct kgdb_arch - Describe architecture specific values.
244 * @gdb_bpt_instr: The instruction to trigger a breakpoint.
245 * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
246 * @set_breakpoint: Allow an architecture to specify how to set a software
247 * breakpoint.
248 * @remove_breakpoint: Allow an architecture to specify how to remove a
249 * software breakpoint.
250 * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
251 * breakpoint.
252 * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
253 * hardware breakpoint.
254 * @disable_hw_break: Allow an architecture to specify how to disable
255 * hardware breakpoints for a single cpu.
256 * @remove_all_hw_break: Allow an architecture to specify how to remove all
257 * hardware breakpoints.
258 * @correct_hw_break: Allow an architecture to specify how to correct the
259 * hardware debug registers.
260 */
261 struct kgdb_arch {
262 unsigned char gdb_bpt_instr[BREAK_INSTR_SIZE];
263 unsigned long flags;
264
265 int (*set_breakpoint)(unsigned long, char *);
266 int (*remove_breakpoint)(unsigned long, char *);
267 int (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
268 int (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
269 void (*disable_hw_break)(struct pt_regs *regs);
270 void (*remove_all_hw_break)(void);
271 void (*correct_hw_break)(void);
272 };
273
274 /**
275 * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
276 * @name: Name of the I/O driver.
277 * @read_char: Pointer to a function that will return one char.
278 * @write_char: Pointer to a function that will write one char.
279 * @flush: Pointer to a function that will flush any pending writes.
280 * @init: Pointer to a function that will initialize the device.
281 * @deinit: Pointer to a function that will deinit the device. Implies that
282 * this I/O driver is temporary and expects to be replaced. Called when
283 * an I/O driver is replaced or explicitly unregistered.
284 * @pre_exception: Pointer to a function that will do any prep work for
285 * the I/O driver.
286 * @post_exception: Pointer to a function that will do any cleanup work
287 * for the I/O driver.
288 * @cons: valid if the I/O device is a console; else NULL.
289 */
290 struct kgdb_io {
291 const char *name;
292 int (*read_char) (void);
293 void (*write_char) (u8);
294 void (*flush) (void);
295 int (*init) (void);
296 void (*deinit) (void);
297 void (*pre_exception) (void);
298 void (*post_exception) (void);
299 struct console *cons;
300 };
301
302 extern const struct kgdb_arch arch_kgdb_ops;
303
304 extern unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs);
305
306 extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
307 extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
308 extern struct kgdb_io *dbg_io_ops;
309
310 extern int kgdb_hex2long(char **ptr, unsigned long *long_val);
311 extern char *kgdb_mem2hex(char *mem, char *buf, int count);
312 extern int kgdb_hex2mem(char *buf, char *mem, int count);
313
314 extern int kgdb_isremovedbreak(unsigned long addr);
315 extern int kgdb_has_hit_break(unsigned long addr);
316
317 extern int
318 kgdb_handle_exception(int ex_vector, int signo, int err_code,
319 struct pt_regs *regs);
320 extern int kgdb_nmicallback(int cpu, void *regs);
321 extern int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
322 atomic_t *snd_rdy);
323 extern void gdbstub_exit(int status);
324
325 /*
326 * kgdb and kprobes both use the same (kprobe) blocklist (which makes sense
327 * given they are both typically hooked up to the same trap meaning on most
328 * architectures one cannot be used to debug the other)
329 *
330 * However on architectures where kprobes is not (yet) implemented we permit
331 * breakpoints everywhere rather than blocking everything by default.
332 */
kgdb_within_blocklist(unsigned long addr)333 static inline bool kgdb_within_blocklist(unsigned long addr)
334 {
335 #ifdef CONFIG_KGDB_HONOUR_BLOCKLIST
336 return within_kprobe_blacklist(addr);
337 #else
338 return false;
339 #endif
340 }
341
342 extern int kgdb_single_step;
343 extern atomic_t kgdb_active;
344 #define in_dbg_master() \
345 (irqs_disabled() && (smp_processor_id() == atomic_read(&kgdb_active)))
346 extern bool dbg_is_early;
347 extern void __init dbg_late_init(void);
348 extern void kgdb_panic(const char *msg);
349 extern void kgdb_free_init_mem(void);
350 #else /* ! CONFIG_KGDB */
351 #define in_dbg_master() (0)
352 #define dbg_late_init()
kgdb_panic(const char * msg)353 static inline void kgdb_panic(const char *msg) {}
kgdb_free_init_mem(void)354 static inline void kgdb_free_init_mem(void) { }
kgdb_nmicallback(int cpu,void * regs)355 static inline int kgdb_nmicallback(int cpu, void *regs) { return 1; }
356 #endif /* ! CONFIG_KGDB */
357 #endif /* _KGDB_H_ */
358