include/linux/kgdb.h

0001 /*
0002  * This provides the callbacks and functions that KGDB needs to share between
0003  * the core, I/O and arch-specific portions.
0004  *
0005  * Author: Amit Kale <amitkale@linsyssoft.com> and
0006  *         Tom Rini <trini@kernel.crashing.org>
0007  *
0008  * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc.
0009  * This file is licensed under the terms of the GNU General Public License
0010  * version 2. This program is licensed "as is" without any warranty of any
0011  * kind, whether express or implied.
0012  */
0013 #ifndef _KGDB_H_
0014 #define _KGDB_H_
0015
0016 #include <linux/linkage.h>
0017 #include <linux/init.h>
0018 #include <linux/atomic.h>
0019 #include <linux/kprobes.h>
0020 #ifdef CONFIG_HAVE_ARCH_KGDB
0021 #include <asm/kgdb.h>
0022 #endif
0023
0024 #ifdef CONFIG_KGDB
0025 struct pt_regs;
0026
0027 /**
0028  *  kgdb_skipexception - (optional) exit kgdb_handle_exception early
0029  *  @exception: Exception vector number
0030  *  @regs: Current &struct pt_regs.
0031  *
0032  *  On some architectures it is required to skip a breakpoint
0033  *  exception when it occurs after a breakpoint has been removed.
0034  *  This can be implemented in the architecture specific portion of kgdb.
0035  */
0036 extern int kgdb_skipexception(int exception, struct pt_regs *regs);
0037
0038 struct tasklet_struct;
0039 struct task_struct;
0040 struct uart_port;
0041
0042 /**
0043  *  kgdb_breakpoint - compiled in breakpoint
0044  *
0045  *  This will be implemented as a static inline per architecture.  This
0046  *  function is called by the kgdb core to execute an architecture
0047  *  specific trap to cause kgdb to enter the exception processing.
0048  *
0049  */
0050 void kgdb_breakpoint(void);
0051
0052 extern int kgdb_connected;
0053 extern int kgdb_io_module_registered;
0054
0055 extern atomic_t         kgdb_setting_breakpoint;
0056 extern atomic_t         kgdb_cpu_doing_single_step;
0057
0058 extern struct task_struct   *kgdb_usethread;
0059 extern struct task_struct   *kgdb_contthread;
0060
0061 enum kgdb_bptype {
0062     BP_BREAKPOINT = 0,
0063     BP_HARDWARE_BREAKPOINT,
0064     BP_WRITE_WATCHPOINT,
0065     BP_READ_WATCHPOINT,
0066     BP_ACCESS_WATCHPOINT,
0067     BP_POKE_BREAKPOINT,
0068 };
0069
0070 enum kgdb_bpstate {
0071     BP_UNDEFINED = 0,
0072     BP_REMOVED,
0073     BP_SET,
0074     BP_ACTIVE
0075 };
0076
0077 struct kgdb_bkpt {
0078     unsigned long       bpt_addr;
0079     unsigned char       saved_instr[BREAK_INSTR_SIZE];
0080     enum kgdb_bptype    type;
0081     enum kgdb_bpstate   state;
0082 };
0083
0084 struct dbg_reg_def_t {
0085     char *name;
0086     int size;
0087     int offset;
0088 };
0089
0090 #ifndef DBG_MAX_REG_NUM
0091 #define DBG_MAX_REG_NUM 0
0092 #else
0093 extern struct dbg_reg_def_t dbg_reg_def[];
0094 extern char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs);
0095 extern int dbg_set_reg(int regno, void *mem, struct pt_regs *regs);
0096 #endif
0097 #ifndef KGDB_MAX_BREAKPOINTS
0098 # define KGDB_MAX_BREAKPOINTS   1000
0099 #endif
0100
0101 #define KGDB_HW_BREAKPOINT  1
0102
0103 /*
0104  * Functions each KGDB-supporting architecture must provide:
0105  */
0106
0107 /**
0108  *  kgdb_arch_init - Perform any architecture specific initialization.
0109  *
0110  *  This function will handle the initialization of any architecture
0111  *  specific callbacks.
0112  */
0113 extern int kgdb_arch_init(void);
0114
0115 /**
0116  *  kgdb_arch_exit - Perform any architecture specific uninitalization.
0117  *
0118  *  This function will handle the uninitalization of any architecture
0119  *  specific callbacks, for dynamic registration and unregistration.
0120  */
0121 extern void kgdb_arch_exit(void);
0122
0123 /**
0124  *  pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
0125  *  @gdb_regs: A pointer to hold the registers in the order GDB wants.
0126  *  @regs: The &struct pt_regs of the current process.
0127  *
0128  *  Convert the pt_regs in @regs into the format for registers that
0129  *  GDB expects, stored in @gdb_regs.
0130  */
0131 extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
0132
0133 /**
0134  *  sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
0135  *  @gdb_regs: A pointer to hold the registers in the order GDB wants.
0136  *  @p: The &struct task_struct of the desired process.
0137  *
0138  *  Convert the register values of the sleeping process in @p to
0139  *  the format that GDB expects.
0140  *  This function is called when kgdb does not have access to the
0141  *  &struct pt_regs and therefore it should fill the gdb registers
0142  *  @gdb_regs with what has been saved in &struct thread_struct
0143  *  thread field during switch_to.
0144  */
0145 extern void
0146 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
0147
0148 /**
0149  *  gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
0150  *  @gdb_regs: A pointer to hold the registers we've received from GDB.
0151  *  @regs: A pointer to a &struct pt_regs to hold these values in.
0152  *
0153  *  Convert the GDB regs in @gdb_regs into the pt_regs, and store them
0154  *  in @regs.
0155  */
0156 extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
0157
0158 /**
0159  *  kgdb_arch_handle_exception - Handle architecture specific GDB packets.
0160  *  @vector: The error vector of the exception that happened.
0161  *  @signo: The signal number of the exception that happened.
0162  *  @err_code: The error code of the exception that happened.
0163  *  @remcom_in_buffer: The buffer of the packet we have read.
0164  *  @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
0165  *  @regs: The &struct pt_regs of the current process.
0166  *
0167  *  This function MUST handle the 'c' and 's' command packets,
0168  *  as well packets to set / remove a hardware breakpoint, if used.
0169  *  If there are additional packets which the hardware needs to handle,
0170  *  they are handled here.  The code should return -1 if it wants to
0171  *  process more packets, and a %0 or %1 if it wants to exit from the
0172  *  kgdb callback.
0173  */
0174 extern int
0175 kgdb_arch_handle_exception(int vector, int signo, int err_code,
0176                char *remcom_in_buffer,
0177                char *remcom_out_buffer,
0178                struct pt_regs *regs);
0179
0180 /**
0181  *  kgdb_arch_handle_qxfer_pkt - Handle architecture specific GDB XML
0182  *                   packets.
0183  *  @remcom_in_buffer: The buffer of the packet we have read.
0184  *  @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
0185  */
0186
0187 extern void
0188 kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
0189                char *remcom_out_buffer);
0190
0191 /**
0192  *  kgdb_call_nmi_hook - Call kgdb_nmicallback() on the current CPU
0193  *  @ignored: This parameter is only here to match the prototype.
0194  *
0195  *  If you're using the default implementation of kgdb_roundup_cpus()
0196  *  this function will be called per CPU.  If you don't implement
0197  *  kgdb_call_nmi_hook() a default will be used.
0198  */
0199
0200 extern void kgdb_call_nmi_hook(void *ignored);
0201
0202 /**
0203  *  kgdb_roundup_cpus - Get other CPUs into a holding pattern
0204  *
0205  *  On SMP systems, we need to get the attention of the other CPUs
0206  *  and get them into a known state.  This should do what is needed
0207  *  to get the other CPUs to call kgdb_wait(). Note that on some arches,
0208  *  the NMI approach is not used for rounding up all the CPUs.  Normally
0209  *  those architectures can just not implement this and get the default.
0210  *
0211  *  On non-SMP systems, this is not called.
0212  */
0213 extern void kgdb_roundup_cpus(void);
0214
0215 /**
0216  *  kgdb_arch_set_pc - Generic call back to the program counter
0217  *  @regs: Current &struct pt_regs.
0218  *  @pc: The new value for the program counter
0219  *
0220  *  This function handles updating the program counter and requires an
0221  *  architecture specific implementation.
0222  */
0223 extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc);
0224
0225
0226 /* Optional functions. */
0227 extern int kgdb_validate_break_address(unsigned long addr);
0228 extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);
0229 extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);
0230
0231 /**
0232  *  kgdb_arch_late - Perform any architecture specific initialization.
0233  *
0234  *  This function will handle the late initialization of any
0235  *  architecture specific callbacks.  This is an optional function for
0236  *  handling things like late initialization of hw breakpoints.  The
0237  *  default implementation does nothing.
0238  */
0239 extern void kgdb_arch_late(void);
0240
0241
0242 /**
0243  * struct kgdb_arch - Describe architecture specific values.
0244  * @gdb_bpt_instr: The instruction to trigger a breakpoint.
0245  * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
0246  * @set_breakpoint: Allow an architecture to specify how to set a software
0247  * breakpoint.
0248  * @remove_breakpoint: Allow an architecture to specify how to remove a
0249  * software breakpoint.
0250  * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
0251  * breakpoint.
0252  * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
0253  * hardware breakpoint.
0254  * @disable_hw_break: Allow an architecture to specify how to disable
0255  * hardware breakpoints for a single cpu.
0256  * @remove_all_hw_break: Allow an architecture to specify how to remove all
0257  * hardware breakpoints.
0258  * @correct_hw_break: Allow an architecture to specify how to correct the
0259  * hardware debug registers.
0260  * @enable_nmi: Manage NMI-triggered entry to KGDB
0261  */
0262 struct kgdb_arch {
0263     unsigned char       gdb_bpt_instr[BREAK_INSTR_SIZE];
0264     unsigned long       flags;
0265
0266     int (*set_breakpoint)(unsigned long, char *);
0267     int (*remove_breakpoint)(unsigned long, char *);
0268     int (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
0269     int (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
0270     void    (*disable_hw_break)(struct pt_regs *regs);
0271     void    (*remove_all_hw_break)(void);
0272     void    (*correct_hw_break)(void);
0273
0274     void    (*enable_nmi)(bool on);
0275 };
0276
0277 /**
0278  * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
0279  * @name: Name of the I/O driver.
0280  * @read_char: Pointer to a function that will return one char.
0281  * @write_char: Pointer to a function that will write one char.
0282  * @flush: Pointer to a function that will flush any pending writes.
0283  * @init: Pointer to a function that will initialize the device.
0284  * @deinit: Pointer to a function that will deinit the device. Implies that
0285  * this I/O driver is temporary and expects to be replaced. Called when
0286  * an I/O driver is replaced or explicitly unregistered.
0287  * @pre_exception: Pointer to a function that will do any prep work for
0288  * the I/O driver.
0289  * @post_exception: Pointer to a function that will do any cleanup work
0290  * for the I/O driver.
0291  * @cons: valid if the I/O device is a console; else NULL.
0292  */
0293 struct kgdb_io {
0294     const char      *name;
0295     int         (*read_char) (void);
0296     void            (*write_char) (u8);
0297     void            (*flush) (void);
0298     int         (*init) (void);
0299     void            (*deinit) (void);
0300     void            (*pre_exception) (void);
0301     void            (*post_exception) (void);
0302     struct console      *cons;
0303 };
0304
0305 extern const struct kgdb_arch       arch_kgdb_ops;
0306
0307 extern unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs);
0308
0309 #ifdef CONFIG_SERIAL_KGDB_NMI
0310 extern int kgdb_register_nmi_console(void);
0311 extern int kgdb_unregister_nmi_console(void);
0312 extern bool kgdb_nmi_poll_knock(void);
0313 #else
0314 static inline int kgdb_register_nmi_console(void) { return 0; }
0315 static inline int kgdb_unregister_nmi_console(void) { return 0; }
0316 static inline bool kgdb_nmi_poll_knock(void) { return true; }
0317 #endif
0318
0319 extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
0320 extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
0321 extern struct kgdb_io *dbg_io_ops;
0322
0323 extern int kgdb_hex2long(char **ptr, unsigned long *long_val);
0324 extern char *kgdb_mem2hex(char *mem, char *buf, int count);
0325 extern int kgdb_hex2mem(char *buf, char *mem, int count);
0326
0327 extern int kgdb_isremovedbreak(unsigned long addr);
0328 extern int kgdb_has_hit_break(unsigned long addr);
0329
0330 extern int
0331 kgdb_handle_exception(int ex_vector, int signo, int err_code,
0332               struct pt_regs *regs);
0333 extern int kgdb_nmicallback(int cpu, void *regs);
0334 extern int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
0335               atomic_t *snd_rdy);
0336 extern void gdbstub_exit(int status);
0337
0338 /*
0339  * kgdb and kprobes both use the same (kprobe) blocklist (which makes sense
0340  * given they are both typically hooked up to the same trap meaning on most
0341  * architectures one cannot be used to debug the other)
0342  *
0343  * However on architectures where kprobes is not (yet) implemented we permit
0344  * breakpoints everywhere rather than blocking everything by default.
0345  */
0346 static inline bool kgdb_within_blocklist(unsigned long addr)
0347 {
0348 #ifdef CONFIG_KGDB_HONOUR_BLOCKLIST
0349     return within_kprobe_blacklist(addr);
0350 #else
0351     return false;
0352 #endif
0353 }
0354
0355 extern int          kgdb_single_step;
0356 extern atomic_t         kgdb_active;
0357 #define in_dbg_master() \
0358     (irqs_disabled() && (smp_processor_id() == atomic_read(&kgdb_active)))
0359 extern bool dbg_is_early;
0360 extern void __init dbg_late_init(void);
0361 extern void kgdb_panic(const char *msg);
0362 extern void kgdb_free_init_mem(void);
0363 #else /* ! CONFIG_KGDB */
0364 #define in_dbg_master() (0)
0365 #define dbg_late_init()
0366 static inline void kgdb_panic(const char *msg) {}
0367 static inline void kgdb_free_init_mem(void) { }
0368 #endif /* ! CONFIG_KGDB */
0369 #endif /* _KGDB_H_ */