include/linux/kgdb.h

   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 initalization.
 109  *
 110  *      This function will handle the initalization 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 initalization.
 233  *
 234  *      This function will handle the late initalization 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  * @enable_nmi: Manage NMI-triggered entry to KGDB
 261  */
 262 struct kgdb_arch {
 263         unsigned char           gdb_bpt_instr[BREAK_INSTR_SIZE];
 264         unsigned long           flags;
 265
 266         int     (*set_breakpoint)(unsigned long, char *);
 267         int     (*remove_breakpoint)(unsigned long, char *);
 268         int     (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
 269         int     (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
 270         void    (*disable_hw_break)(struct pt_regs *regs);
 271         void    (*remove_all_hw_break)(void);
 272         void    (*correct_hw_break)(void);
 273
 274         void    (*enable_nmi)(bool on);
 275 };
 276
 277 /**
 278  * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
 279  * @name: Name of the I/O driver.
 280  * @read_char: Pointer to a function that will return one char.
 281  * @write_char: Pointer to a function that will write one char.
 282  * @flush: Pointer to a function that will flush any pending writes.
 283  * @init: Pointer to a function that will initialize the device.
 284  * @deinit: Pointer to a function that will deinit the device. Implies that
 285  * this I/O driver is temporary and expects to be replaced. Called when
 286  * an I/O driver is replaced or explicitly unregistered.
 287  * @pre_exception: Pointer to a function that will do any prep work for
 288  * the I/O driver.
 289  * @post_exception: Pointer to a function that will do any cleanup work
 290  * for the I/O driver.
 291  * @cons: valid if the I/O device is a console; else NULL.
 292  */
 293 struct kgdb_io {
 294         const char              *name;
 295         int                     (*read_char) (void);
 296         void                    (*write_char) (u8);
 297         void                    (*flush) (void);
 298         int                     (*init) (void);
 299         void                    (*deinit) (void);
 300         void                    (*pre_exception) (void);
 301         void                    (*post_exception) (void);
 302         struct console          *cons;
 303 };
 304
 305 extern const struct kgdb_arch           arch_kgdb_ops;
 306
 307 extern unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs);
 308
 309 #ifdef CONFIG_SERIAL_KGDB_NMI
 310 extern int kgdb_register_nmi_console(void);
 311 extern int kgdb_unregister_nmi_console(void);
 312 extern bool kgdb_nmi_poll_knock(void);
 313 #else
 314 static inline int kgdb_register_nmi_console(void) { return 0; }
 315 static inline int kgdb_unregister_nmi_console(void) { return 0; }
 316 static inline bool kgdb_nmi_poll_knock(void) { return true; }
 317 #endif
 318
 319 extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
 320 extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
 321 extern struct kgdb_io *dbg_io_ops;
 322
 323 extern int kgdb_hex2long(char **ptr, unsigned long *long_val);
 324 extern char *kgdb_mem2hex(char *mem, char *buf, int count);
 325 extern int kgdb_hex2mem(char *buf, char *mem, int count);
 326
 327 extern int kgdb_isremovedbreak(unsigned long addr);
 328 extern int kgdb_has_hit_break(unsigned long addr);
 329
 330 extern int
 331 kgdb_handle_exception(int ex_vector, int signo, int err_code,
 332                       struct pt_regs *regs);
 333 extern int kgdb_nmicallback(int cpu, void *regs);
 334 extern int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
 335                           atomic_t *snd_rdy);
 336 extern void gdbstub_exit(int status);
 337
 338 /*
 339  * kgdb and kprobes both use the same (kprobe) blocklist (which makes sense
 340  * given they are both typically hooked up to the same trap meaning on most
 341  * architectures one cannot be used to debug the other)
 342  *
 343  * However on architectures where kprobes is not (yet) implemented we permit
 344  * breakpoints everywhere rather than blocking everything by default.
 345  */
 346 static inline bool kgdb_within_blocklist(unsigned long addr)
 347 {
 348 #ifdef CONFIG_KGDB_HONOUR_BLOCKLIST
 349         return within_kprobe_blacklist(addr);
 350 #else
 351         return false;
 352 #endif
 353 }
 354
 355 extern int                      kgdb_single_step;
 356 extern atomic_t                 kgdb_active;
 357 #define in_dbg_master() \
 358         (irqs_disabled() && (smp_processor_id() == atomic_read(&kgdb_active)))
 359 extern bool dbg_is_early;
 360 extern void __init dbg_late_init(void);
 361 extern void kgdb_panic(const char *msg);
 362 extern void kgdb_free_init_mem(void);
 363 #else /* ! CONFIG_KGDB */
 364 #define in_dbg_master() (0)
 365 #define dbg_late_init()
 366 static inline void kgdb_panic(const char *msg) {}
 367 static inline void kgdb_free_init_mem(void) { }
 368 #endif /* ! CONFIG_KGDB */
 369 #endif /* _KGDB_H_ */