1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * This provides the callbacks and functions that KGDB needs to share between 4 * the core, I/O and arch-specific portions. 5 * 6 * Author: Amit Kale <amitkale@linsyssoft.com> and 7 * Tom Rini <trini@kernel.crashing.org> 8 * 9 * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc. 10 */ 11 #ifndef _KGDB_H_ 12 #define _KGDB_H_ 13 14 #include <linux/linkage.h> 15 #include <linux/init.h> 16 #include <linux/atomic.h> 17 #include <linux/kprobes.h> 18 #ifdef CONFIG_HAVE_ARCH_KGDB 19 #include <asm/kgdb.h> 20 #endif 21 22 #ifdef CONFIG_KGDB 23 struct pt_regs; 24 25 /** 26 * kgdb_skipexception - (optional) exit kgdb_handle_exception early 27 * @exception: Exception vector number 28 * @regs: Current &struct pt_regs. 29 * 30 * On some architectures it is required to skip a breakpoint 31 * exception when it occurs after a breakpoint has been removed. 32 * This can be implemented in the architecture specific portion of kgdb. 33 */ 34 extern int kgdb_skipexception(int exception, struct pt_regs *regs); 35 36 struct tasklet_struct; 37 struct task_struct; 38 struct uart_port; 39 40 /** 41 * kgdb_breakpoint - compiled in breakpoint 42 * 43 * This will be implemented as a static inline per architecture. This 44 * function is called by the kgdb core to execute an architecture 45 * specific trap to cause kgdb to enter the exception processing. 46 * 47 */ 48 void kgdb_breakpoint(void); 49 50 extern int kgdb_connected; 51 extern int kgdb_io_module_registered; 52 53 extern atomic_t kgdb_setting_breakpoint; 54 extern atomic_t kgdb_cpu_doing_single_step; 55 56 extern struct task_struct *kgdb_usethread; 57 extern struct task_struct *kgdb_contthread; 58 59 enum kgdb_bptype { 60 BP_BREAKPOINT = 0, 61 BP_HARDWARE_BREAKPOINT, 62 BP_WRITE_WATCHPOINT, 63 BP_READ_WATCHPOINT, 64 BP_ACCESS_WATCHPOINT, 65 BP_POKE_BREAKPOINT, 66 }; 67 68 enum kgdb_bpstate { 69 BP_UNDEFINED = 0, 70 BP_REMOVED, 71 BP_SET, 72 BP_ACTIVE 73 }; 74 75 struct kgdb_bkpt { 76 unsigned long bpt_addr; 77 unsigned char saved_instr[BREAK_INSTR_SIZE]; 78 enum kgdb_bptype type; 79 enum kgdb_bpstate state; 80 }; 81 82 struct dbg_reg_def_t { 83 char *name; 84 int size; 85 int offset; 86 }; 87 88 #ifndef DBG_MAX_REG_NUM 89 #define DBG_MAX_REG_NUM 0 90 #else 91 extern struct dbg_reg_def_t dbg_reg_def[]; 92 extern char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs); 93 extern int dbg_set_reg(int regno, void *mem, struct pt_regs *regs); 94 #endif 95 #ifndef KGDB_MAX_BREAKPOINTS 96 # define KGDB_MAX_BREAKPOINTS 1000 97 #endif 98 99 #define KGDB_HW_BREAKPOINT 1 100 101 /* 102 * Functions each KGDB-supporting architecture must provide: 103 */ 104 105 /** 106 * kgdb_arch_init - Perform any architecture specific initialization. 107 * 108 * This function will handle the initialization of any architecture 109 * specific callbacks. 110 */ 111 extern int kgdb_arch_init(void); 112 113 /** 114 * kgdb_arch_exit - Perform any architecture specific uninitalization. 115 * 116 * This function will handle the uninitalization of any architecture 117 * specific callbacks, for dynamic registration and unregistration. 118 */ 119 extern void kgdb_arch_exit(void); 120 121 /** 122 * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs 123 * @gdb_regs: A pointer to hold the registers in the order GDB wants. 124 * @regs: The &struct pt_regs of the current process. 125 * 126 * Convert the pt_regs in @regs into the format for registers that 127 * GDB expects, stored in @gdb_regs. 128 */ 129 extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs); 130 131 /** 132 * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs 133 * @gdb_regs: A pointer to hold the registers in the order GDB wants. 134 * @p: The &struct task_struct of the desired process. 135 * 136 * Convert the register values of the sleeping process in @p to 137 * the format that GDB expects. 138 * This function is called when kgdb does not have access to the 139 * &struct pt_regs and therefore it should fill the gdb registers 140 * @gdb_regs with what has been saved in &struct thread_struct 141 * thread field during switch_to. 142 */ 143 extern void 144 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p); 145 146 /** 147 * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. 148 * @gdb_regs: A pointer to hold the registers we've received from GDB. 149 * @regs: A pointer to a &struct pt_regs to hold these values in. 150 * 151 * Convert the GDB regs in @gdb_regs into the pt_regs, and store them 152 * in @regs. 153 */ 154 extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs); 155 156 /** 157 * kgdb_arch_handle_exception - Handle architecture specific GDB packets. 158 * @vector: The error vector of the exception that happened. 159 * @signo: The signal number of the exception that happened. 160 * @err_code: The error code of the exception that happened. 161 * @remcom_in_buffer: The buffer of the packet we have read. 162 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. 163 * @regs: The &struct pt_regs of the current process. 164 * 165 * This function MUST handle the 'c' and 's' command packets, 166 * as well packets to set / remove a hardware breakpoint, if used. 167 * If there are additional packets which the hardware needs to handle, 168 * they are handled here. The code should return -1 if it wants to 169 * process more packets, and a %0 or %1 if it wants to exit from the 170 * kgdb callback. 171 */ 172 extern int 173 kgdb_arch_handle_exception(int vector, int signo, int err_code, 174 char *remcom_in_buffer, 175 char *remcom_out_buffer, 176 struct pt_regs *regs); 177 178 /** 179 * kgdb_arch_handle_qxfer_pkt - Handle architecture specific GDB XML 180 * packets. 181 * @remcom_in_buffer: The buffer of the packet we have read. 182 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. 183 */ 184 185 extern void 186 kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer, 187 char *remcom_out_buffer); 188 189 /** 190 * kgdb_call_nmi_hook - Call kgdb_nmicallback() on the current CPU 191 * @ignored: This parameter is only here to match the prototype. 192 * 193 * If you're using the default implementation of kgdb_roundup_cpus() 194 * this function will be called per CPU. If you don't implement 195 * kgdb_call_nmi_hook() a default will be used. 196 */ 197 198 extern void kgdb_call_nmi_hook(void *ignored); 199 200 /** 201 * kgdb_roundup_cpus - Get other CPUs into a holding pattern 202 * 203 * On SMP systems, we need to get the attention of the other CPUs 204 * and get them into a known state. This should do what is needed 205 * to get the other CPUs to call kgdb_wait(). Note that on some arches, 206 * the NMI approach is not used for rounding up all the CPUs. Normally 207 * those architectures can just not implement this and get the default. 208 * 209 * On non-SMP systems, this is not called. 210 */ 211 extern void kgdb_roundup_cpus(void); 212 213 /** 214 * kgdb_arch_set_pc - Generic call back to the program counter 215 * @regs: Current &struct pt_regs. 216 * @pc: The new value for the program counter 217 * 218 * This function handles updating the program counter and requires an 219 * architecture specific implementation. 220 */ 221 extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc); 222 223 224 /* Optional functions. */ 225 extern int kgdb_validate_break_address(unsigned long addr); 226 extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt); 227 extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt); 228 229 /** 230 * kgdb_arch_late - Perform any architecture specific initialization. 231 * 232 * This function will handle the late initialization of any 233 * architecture specific callbacks. This is an optional function for 234 * handling things like late initialization of hw breakpoints. The 235 * default implementation does nothing. 236 */ 237 extern void kgdb_arch_late(void); 238 239 240 /** 241 * struct kgdb_arch - Describe architecture specific values. 242 * @gdb_bpt_instr: The instruction to trigger a breakpoint. 243 * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT. 244 * @set_breakpoint: Allow an architecture to specify how to set a software 245 * breakpoint. 246 * @remove_breakpoint: Allow an architecture to specify how to remove a 247 * software breakpoint. 248 * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware 249 * breakpoint. 250 * @remove_hw_breakpoint: Allow an architecture to specify how to remove a 251 * hardware breakpoint. 252 * @disable_hw_break: Allow an architecture to specify how to disable 253 * hardware breakpoints for a single cpu. 254 * @remove_all_hw_break: Allow an architecture to specify how to remove all 255 * hardware breakpoints. 256 * @correct_hw_break: Allow an architecture to specify how to correct the 257 * hardware debug registers. 258 */ 259 struct kgdb_arch { 260 unsigned char gdb_bpt_instr[BREAK_INSTR_SIZE]; 261 unsigned long flags; 262 263 int (*set_breakpoint)(unsigned long, char *); 264 int (*remove_breakpoint)(unsigned long, char *); 265 int (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype); 266 int (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype); 267 void (*disable_hw_break)(struct pt_regs *regs); 268 void (*remove_all_hw_break)(void); 269 void (*correct_hw_break)(void); 270 }; 271 272 /** 273 * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB. 274 * @name: Name of the I/O driver. 275 * @read_char: Pointer to a function that will return one char. 276 * @write_char: Pointer to a function that will write one char. 277 * @flush: Pointer to a function that will flush any pending writes. 278 * @init: Pointer to a function that will initialize the device. 279 * @deinit: Pointer to a function that will deinit the device. Implies that 280 * this I/O driver is temporary and expects to be replaced. Called when 281 * an I/O driver is replaced or explicitly unregistered. 282 * @pre_exception: Pointer to a function that will do any prep work for 283 * the I/O driver. 284 * @post_exception: Pointer to a function that will do any cleanup work 285 * for the I/O driver. 286 * @cons: valid if the I/O device is a console; else NULL. 287 */ 288 struct kgdb_io { 289 const char *name; 290 int (*read_char) (void); 291 void (*write_char) (u8); 292 void (*flush) (void); 293 int (*init) (void); 294 void (*deinit) (void); 295 void (*pre_exception) (void); 296 void (*post_exception) (void); 297 struct console *cons; 298 }; 299 300 extern const struct kgdb_arch arch_kgdb_ops; 301 302 extern unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs); 303 304 extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops); 305 extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops); 306 extern struct kgdb_io *dbg_io_ops; 307 308 extern int kgdb_hex2long(char **ptr, unsigned long *long_val); 309 extern char *kgdb_mem2hex(char *mem, char *buf, int count); 310 extern int kgdb_hex2mem(char *buf, char *mem, int count); 311 312 extern int kgdb_isremovedbreak(unsigned long addr); 313 extern int kgdb_has_hit_break(unsigned long addr); 314 315 extern int 316 kgdb_handle_exception(int ex_vector, int signo, int err_code, 317 struct pt_regs *regs); 318 extern int kgdb_nmicallback(int cpu, void *regs); 319 extern int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, 320 atomic_t *snd_rdy); 321 extern void gdbstub_exit(int status); 322 323 /* 324 * kgdb and kprobes both use the same (kprobe) blocklist (which makes sense 325 * given they are both typically hooked up to the same trap meaning on most 326 * architectures one cannot be used to debug the other) 327 * 328 * However on architectures where kprobes is not (yet) implemented we permit 329 * breakpoints everywhere rather than blocking everything by default. 330 */ 331 static inline bool kgdb_within_blocklist(unsigned long addr) 332 { 333 #ifdef CONFIG_KGDB_HONOUR_BLOCKLIST 334 return within_kprobe_blacklist(addr); 335 #else 336 return false; 337 #endif 338 } 339 340 extern int kgdb_single_step; 341 extern atomic_t kgdb_active; 342 #define in_dbg_master() \ 343 (irqs_disabled() && (smp_processor_id() == atomic_read(&kgdb_active))) 344 extern bool dbg_is_early; 345 extern void __init dbg_late_init(void); 346 extern void kgdb_panic(const char *msg); 347 extern void kgdb_free_init_mem(void); 348 #else /* ! CONFIG_KGDB */ 349 #define in_dbg_master() (0) 350 #define dbg_late_init() 351 static inline void kgdb_panic(const char *msg) {} 352 static inline void kgdb_free_init_mem(void) { } 353 static inline int kgdb_nmicallback(int cpu, void *regs) { return 1; } 354 #endif /* ! CONFIG_KGDB */ 355 #endif /* _KGDB_H_ */ 356