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