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 #ifdef CONFIG_HAVE_ARCH_KGDB
  20 #include <asm/kgdb.h>
  21 #endif
  22
  23 #ifdef CONFIG_KGDB
  24 struct pt_regs;
  25
  26 /**
  27  *      kgdb_skipexception - (optional) exit kgdb_handle_exception early
  28  *      @exception: Exception vector number
  29  *      @regs: Current &struct pt_regs.
  30  *
  31  *      On some architectures it is required to skip a breakpoint
  32  *      exception when it occurs after a breakpoint has been removed.
  33  *      This can be implemented in the architecture specific portion of kgdb.
  34  */
  35 extern int kgdb_skipexception(int exception, struct pt_regs *regs);
  36
  37 struct tasklet_struct;
  38 struct task_struct;
  39 struct uart_port;
  40
  41 /**
  42  *      kgdb_breakpoint - compiled in breakpoint
  43  *
  44  *      This will be implemented as a static inline per architecture.  This
  45  *      function is called by the kgdb core to execute an architecture
  46  *      specific trap to cause kgdb to enter the exception processing.
  47  *
  48  */
  49 void kgdb_breakpoint(void);
  50
  51 extern int kgdb_connected;
  52 extern int kgdb_io_module_registered;
  53
  54 extern atomic_t                 kgdb_setting_breakpoint;
  55 extern atomic_t                 kgdb_cpu_doing_single_step;
  56
  57 extern struct task_struct       *kgdb_usethread;
  58 extern struct task_struct       *kgdb_contthread;
  59
  60 enum kgdb_bptype {
  61         BP_BREAKPOINT = 0,
  62         BP_HARDWARE_BREAKPOINT,
  63         BP_WRITE_WATCHPOINT,
  64         BP_READ_WATCHPOINT,
  65         BP_ACCESS_WATCHPOINT,
  66         BP_POKE_BREAKPOINT,
  67 };
  68
  69 enum kgdb_bpstate {
  70         BP_UNDEFINED = 0,
  71         BP_REMOVED,
  72         BP_SET,
  73         BP_ACTIVE
  74 };
  75
  76 struct kgdb_bkpt {
  77         unsigned long           bpt_addr;
  78         unsigned char           saved_instr[BREAK_INSTR_SIZE];
  79         enum kgdb_bptype        type;
  80         enum kgdb_bpstate       state;
  81 };
  82
  83 struct dbg_reg_def_t {
  84         char *name;
  85         int size;
  86         int offset;
  87 };
  88
  89 #ifndef DBG_MAX_REG_NUM
  90 #define DBG_MAX_REG_NUM 0
  91 #else
  92 extern struct dbg_reg_def_t dbg_reg_def[];
  93 extern char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs);
  94 extern int dbg_set_reg(int regno, void *mem, struct pt_regs *regs);
  95 #endif
  96 #ifndef KGDB_MAX_BREAKPOINTS
  97 # define KGDB_MAX_BREAKPOINTS   1000
  98 #endif
  99
 100 #define KGDB_HW_BREAKPOINT      1
 101
 102 /*
 103  * Functions each KGDB-supporting architecture must provide:
 104  */
 105
 106 /**
 107  *      kgdb_arch_init - Perform any architecture specific initalization.
 108  *
 109  *      This function will handle the initalization of any architecture
 110  *      specific callbacks.
 111  */
 112 extern int kgdb_arch_init(void);
 113
 114 /**
 115  *      kgdb_arch_exit - Perform any architecture specific uninitalization.
 116  *
 117  *      This function will handle the uninitalization of any architecture
 118  *      specific callbacks, for dynamic registration and unregistration.
 119  */
 120 extern void kgdb_arch_exit(void);
 121
 122 /**
 123  *      pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
 124  *      @gdb_regs: A pointer to hold the registers in the order GDB wants.
 125  *      @regs: The &struct pt_regs of the current process.
 126  *
 127  *      Convert the pt_regs in @regs into the format for registers that
 128  *      GDB expects, stored in @gdb_regs.
 129  */
 130 extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
 131
 132 /**
 133  *      sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
 134  *      @gdb_regs: A pointer to hold the registers in the order GDB wants.
 135  *      @p: The &struct task_struct of the desired process.
 136  *
 137  *      Convert the register values of the sleeping process in @p to
 138  *      the format that GDB expects.
 139  *      This function is called when kgdb does not have access to the
 140  *      &struct pt_regs and therefore it should fill the gdb registers
 141  *      @gdb_regs with what has been saved in &struct thread_struct
 142  *      thread field during switch_to.
 143  */
 144 extern void
 145 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
 146
 147 /**
 148  *      gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
 149  *      @gdb_regs: A pointer to hold the registers we've received from GDB.
 150  *      @regs: A pointer to a &struct pt_regs to hold these values in.
 151  *
 152  *      Convert the GDB regs in @gdb_regs into the pt_regs, and store them
 153  *      in @regs.
 154  */
 155 extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
 156
 157 /**
 158  *      kgdb_arch_handle_exception - Handle architecture specific GDB packets.
 159  *      @vector: The error vector of the exception that happened.
 160  *      @signo: The signal number of the exception that happened.
 161  *      @err_code: The error code of the exception that happened.
 162  *      @remcom_in_buffer: The buffer of the packet we have read.
 163  *      @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
 164  *      @regs: The &struct pt_regs of the current process.
 165  *
 166  *      This function MUST handle the 'c' and 's' command packets,
 167  *      as well packets to set / remove a hardware breakpoint, if used.
 168  *      If there are additional packets which the hardware needs to handle,
 169  *      they are handled here.  The code should return -1 if it wants to
 170  *      process more packets, and a %0 or %1 if it wants to exit from the
 171  *      kgdb callback.
 172  */
 173 extern int
 174 kgdb_arch_handle_exception(int vector, int signo, int err_code,
 175                            char *remcom_in_buffer,
 176                            char *remcom_out_buffer,
 177                            struct pt_regs *regs);
 178
 179 /**
 180  *      kgdb_roundup_cpus - Get other CPUs into a holding pattern
 181  *      @flags: Current IRQ state
 182  *
 183  *      On SMP systems, we need to get the attention of the other CPUs
 184  *      and get them into a known state.  This should do what is needed
 185  *      to get the other CPUs to call kgdb_wait(). Note that on some arches,
 186  *      the NMI approach is not used for rounding up all the CPUs. For example,
 187  *      in case of MIPS, smp_call_function() is used to roundup CPUs. In
 188  *      this case, we have to make sure that interrupts are enabled before
 189  *      calling smp_call_function(). The argument to this function is
 190  *      the flags that will be used when restoring the interrupts. There is
 191  *      local_irq_save() call before kgdb_roundup_cpus().
 192  *
 193  *      On non-SMP systems, this is not called.
 194  */
 195 extern void kgdb_roundup_cpus(unsigned long flags);
 196
 197 /**
 198  *      kgdb_arch_set_pc - Generic call back to the program counter
 199  *      @regs: Current &struct pt_regs.
 200  *  @pc: The new value for the program counter
 201  *
 202  *      This function handles updating the program counter and requires an
 203  *      architecture specific implementation.
 204  */
 205 extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc);
 206
 207
 208 /* Optional functions. */
 209 extern int kgdb_validate_break_address(unsigned long addr);
 210 extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);
 211 extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);
 212
 213 /**
 214  *      kgdb_arch_late - Perform any architecture specific initalization.
 215  *
 216  *      This function will handle the late initalization of any
 217  *      architecture specific callbacks.  This is an optional function for
 218  *      handling things like late initialization of hw breakpoints.  The
 219  *      default implementation does nothing.
 220  */
 221 extern void kgdb_arch_late(void);
 222
 223
 224 /**
 225  * struct kgdb_arch - Describe architecture specific values.
 226  * @gdb_bpt_instr: The instruction to trigger a breakpoint.
 227  * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
 228  * @set_breakpoint: Allow an architecture to specify how to set a software
 229  * breakpoint.
 230  * @remove_breakpoint: Allow an architecture to specify how to remove a
 231  * software breakpoint.
 232  * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
 233  * breakpoint.
 234  * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
 235  * hardware breakpoint.
 236  * @disable_hw_break: Allow an architecture to specify how to disable
 237  * hardware breakpoints for a single cpu.
 238  * @remove_all_hw_break: Allow an architecture to specify how to remove all
 239  * hardware breakpoints.
 240  * @correct_hw_break: Allow an architecture to specify how to correct the
 241  * hardware debug registers.
 242  * @enable_nmi: Manage NMI-triggered entry to KGDB
 243  */
 244 struct kgdb_arch {
 245         unsigned char           gdb_bpt_instr[BREAK_INSTR_SIZE];
 246         unsigned long           flags;
 247
 248         int     (*set_breakpoint)(unsigned long, char *);
 249         int     (*remove_breakpoint)(unsigned long, char *);
 250         int     (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
 251         int     (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
 252         void    (*disable_hw_break)(struct pt_regs *regs);
 253         void    (*remove_all_hw_break)(void);
 254         void    (*correct_hw_break)(void);
 255
 256         void    (*enable_nmi)(bool on);
 257 };
 258
 259 /**
 260  * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
 261  * @name: Name of the I/O driver.
 262  * @read_char: Pointer to a function that will return one char.
 263  * @write_char: Pointer to a function that will write one char.
 264  * @flush: Pointer to a function that will flush any pending writes.
 265  * @init: Pointer to a function that will initialize the device.
 266  * @pre_exception: Pointer to a function that will do any prep work for
 267  * the I/O driver.
 268  * @post_exception: Pointer to a function that will do any cleanup work
 269  * for the I/O driver.
 270  * @is_console: 1 if the end device is a console 0 if the I/O device is
 271  * not a console
 272  */
 273 struct kgdb_io {
 274         const char              *name;
 275         int                     (*read_char) (void);
 276         void                    (*write_char) (u8);
 277         void                    (*flush) (void);
 278         int                     (*init) (void);
 279         void                    (*pre_exception) (void);
 280         void                    (*post_exception) (void);
 281         int                     is_console;
 282 };
 283
 284 extern struct kgdb_arch         arch_kgdb_ops;
 285
 286 extern unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs);
 287
 288 #ifdef CONFIG_SERIAL_KGDB_NMI
 289 extern int kgdb_register_nmi_console(void);
 290 extern int kgdb_unregister_nmi_console(void);
 291 extern bool kgdb_nmi_poll_knock(void);
 292 #else
 293 static inline int kgdb_register_nmi_console(void) { return 0; }
 294 static inline int kgdb_unregister_nmi_console(void) { return 0; }
 295 static inline bool kgdb_nmi_poll_knock(void) { return 1; }
 296 #endif
 297
 298 extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
 299 extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
 300 extern struct kgdb_io *dbg_io_ops;
 301
 302 extern int kgdb_hex2long(char **ptr, unsigned long *long_val);
 303 extern char *kgdb_mem2hex(char *mem, char *buf, int count);
 304 extern int kgdb_hex2mem(char *buf, char *mem, int count);
 305
 306 extern int kgdb_isremovedbreak(unsigned long addr);
 307 extern void kgdb_schedule_breakpoint(void);
 308
 309 extern int
 310 kgdb_handle_exception(int ex_vector, int signo, int err_code,
 311                       struct pt_regs *regs);
 312 extern int kgdb_nmicallback(int cpu, void *regs);
 313 extern void gdbstub_exit(int status);
 314
 315 extern int                      kgdb_single_step;
 316 extern atomic_t                 kgdb_active;
 317 #define in_dbg_master() \
 318         (raw_smp_processor_id() == atomic_read(&kgdb_active))
 319 extern bool dbg_is_early;
 320 extern void __init dbg_late_init(void);
 321 #else /* ! CONFIG_KGDB */
 322 #define in_dbg_master() (0)
 323 #define dbg_late_init()
 324 #endif /* ! CONFIG_KGDB */
 325 #endif /* _KGDB_H_ */