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/serial_8250.h>
  17 #include <linux/linkage.h>
  18 #include <linux/init.h>
  19 #include <linux/atomic.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_roundup_cpus - Get other CPUs into a holding pattern
 182  *      @flags: Current IRQ state
 183  *
 184  *      On SMP systems, we need to get the attention of the other CPUs
 185  *      and get them into a known state.  This should do what is needed
 186  *      to get the other CPUs to call kgdb_wait(). Note that on some arches,
 187  *      the NMI approach is not used for rounding up all the CPUs. For example,
 188  *      in case of MIPS, smp_call_function() is used to roundup CPUs. In
 189  *      this case, we have to make sure that interrupts are enabled before
 190  *      calling smp_call_function(). The argument to this function is
 191  *      the flags that will be used when restoring the interrupts. There is
 192  *      local_irq_save() call before kgdb_roundup_cpus().
 193  *
 194  *      On non-SMP systems, this is not called.
 195  */
 196 extern void kgdb_roundup_cpus(unsigned long flags);
 197
 198 /**
 199  *      kgdb_arch_set_pc - Generic call back to the program counter
 200  *      @regs: Current &struct pt_regs.
 201  *  @pc: The new value for the program counter
 202  *
 203  *      This function handles updating the program counter and requires an
 204  *      architecture specific implementation.
 205  */
 206 extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc);
 207
 208
 209 /* Optional functions. */
 210 extern int kgdb_validate_break_address(unsigned long addr);
 211 extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);
 212 extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);
 213
 214 /**
 215  *      kgdb_arch_late - Perform any architecture specific initalization.
 216  *
 217  *      This function will handle the late initalization of any
 218  *      architecture specific callbacks.  This is an optional function for
 219  *      handling things like late initialization of hw breakpoints.  The
 220  *      default implementation does nothing.
 221  */
 222 extern void kgdb_arch_late(void);
 223
 224
 225 /**
 226  * struct kgdb_arch - Describe architecture specific values.
 227  * @gdb_bpt_instr: The instruction to trigger a breakpoint.
 228  * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
 229  * @set_breakpoint: Allow an architecture to specify how to set a software
 230  * breakpoint.
 231  * @remove_breakpoint: Allow an architecture to specify how to remove a
 232  * software breakpoint.
 233  * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
 234  * breakpoint.
 235  * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
 236  * hardware breakpoint.
 237  * @disable_hw_break: Allow an architecture to specify how to disable
 238  * hardware breakpoints for a single cpu.
 239  * @remove_all_hw_break: Allow an architecture to specify how to remove all
 240  * hardware breakpoints.
 241  * @correct_hw_break: Allow an architecture to specify how to correct the
 242  * hardware debug registers.
 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
 257 /**
 258  * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
 259  * @name: Name of the I/O driver.
 260  * @read_char: Pointer to a function that will return one char.
 261  * @write_char: Pointer to a function that will write one char.
 262  * @flush: Pointer to a function that will flush any pending writes.
 263  * @init: Pointer to a function that will initialize the device.
 264  * @pre_exception: Pointer to a function that will do any prep work for
 265  * the I/O driver.
 266  * @post_exception: Pointer to a function that will do any cleanup work
 267  * for the I/O driver.
 268  * @is_console: 1 if the end device is a console 0 if the I/O device is
 269  * not a console
 270  */
 271 struct kgdb_io {
 272         const char              *name;
 273         int                     (*read_char) (void);
 274         void                    (*write_char) (u8);
 275         void                    (*flush) (void);
 276         int                     (*init) (void);
 277         void                    (*pre_exception) (void);
 278         void                    (*post_exception) (void);
 279         int                     is_console;
 280 };
 281
 282 extern struct kgdb_arch         arch_kgdb_ops;
 283
 284 extern unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs);
 285
 286 extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
 287 extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
 288 extern struct kgdb_io *dbg_io_ops;
 289
 290 extern int kgdb_hex2long(char **ptr, unsigned long *long_val);
 291 extern char *kgdb_mem2hex(char *mem, char *buf, int count);
 292 extern int kgdb_hex2mem(char *buf, char *mem, int count);
 293
 294 extern int kgdb_isremovedbreak(unsigned long addr);
 295 extern void kgdb_schedule_breakpoint(void);
 296
 297 extern int
 298 kgdb_handle_exception(int ex_vector, int signo, int err_code,
 299                       struct pt_regs *regs);
 300 extern int kgdb_nmicallback(int cpu, void *regs);
 301 extern void gdbstub_exit(int status);
 302
 303 extern int                      kgdb_single_step;
 304 extern atomic_t                 kgdb_active;
 305 #define in_dbg_master() \
 306         (raw_smp_processor_id() == atomic_read(&kgdb_active))
 307 extern bool dbg_is_early;
 308 extern void __init dbg_late_init(void);
 309 #else /* ! CONFIG_KGDB */
 310 #define in_dbg_master() (0)
 311 #define dbg_late_init()
 312 #endif /* ! CONFIG_KGDB */
 313 #endif /* _KGDB_H_ */