Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 #ifndef _LINUX_PTRACE_H
  2 #define _LINUX_PTRACE_H
  3 /* ptrace.h */
  4 /* structs and defines to help the user use the ptrace system call. */
  5 
  6 /* has the defines to get at the registers. */
  7 
  8 #define PTRACE_TRACEME             0
  9 #define PTRACE_PEEKTEXT            1
 10 #define PTRACE_PEEKDATA            2
 11 #define PTRACE_PEEKUSR             3
 12 #define PTRACE_POKETEXT            4
 13 #define PTRACE_POKEDATA            5
 14 #define PTRACE_POKEUSR             6
 15 #define PTRACE_CONT                7
 16 #define PTRACE_KILL                8
 17 #define PTRACE_SINGLESTEP          9
 18 
 19 #define PTRACE_ATTACH             16
 20 #define PTRACE_DETACH             17
 21 
 22 #define PTRACE_SYSCALL            24
 23 
 24 /* 0x4200-0x4300 are reserved for architecture-independent additions.  */
 25 #define PTRACE_SETOPTIONS       0x4200
 26 #define PTRACE_GETEVENTMSG      0x4201
 27 #define PTRACE_GETSIGINFO       0x4202
 28 #define PTRACE_SETSIGINFO       0x4203
 29 
 30 /* options set using PTRACE_SETOPTIONS */
 31 #define PTRACE_O_TRACESYSGOOD   0x00000001
 32 #define PTRACE_O_TRACEFORK      0x00000002
 33 #define PTRACE_O_TRACEVFORK     0x00000004
 34 #define PTRACE_O_TRACECLONE     0x00000008
 35 #define PTRACE_O_TRACEEXEC      0x00000010
 36 #define PTRACE_O_TRACEVFORKDONE 0x00000020
 37 #define PTRACE_O_TRACEEXIT      0x00000040
 38 
 39 #define PTRACE_O_MASK           0x0000007f
 40 
 41 /* Wait extended result codes for the above trace options.  */
 42 #define PTRACE_EVENT_FORK       1
 43 #define PTRACE_EVENT_VFORK      2
 44 #define PTRACE_EVENT_CLONE      3
 45 #define PTRACE_EVENT_EXEC       4
 46 #define PTRACE_EVENT_VFORK_DONE 5
 47 #define PTRACE_EVENT_EXIT       6
 48 
 49 #include <asm/ptrace.h>
 50 
 51 #ifdef __KERNEL__
 52 /*
 53  * Ptrace flags
 54  *
 55  * The owner ship rules for task->ptrace which holds the ptrace
 56  * flags is simple.  When a task is running it owns it's task->ptrace
 57  * flags.  When the a task is stopped the ptracer owns task->ptrace.
 58  */
 59 
 60 #define PT_PTRACED      0x00000001
 61 #define PT_DTRACE       0x00000002      /* delayed trace (used on m68k, i386) */
 62 #define PT_TRACESYSGOOD 0x00000004
 63 #define PT_PTRACE_CAP   0x00000008      /* ptracer can follow suid-exec */
 64 #define PT_TRACE_FORK   0x00000010
 65 #define PT_TRACE_VFORK  0x00000020
 66 #define PT_TRACE_CLONE  0x00000040
 67 #define PT_TRACE_EXEC   0x00000080
 68 #define PT_TRACE_VFORK_DONE     0x00000100
 69 #define PT_TRACE_EXIT   0x00000200
 70 
 71 #define PT_TRACE_MASK   0x000003f4
 72 
 73 /* single stepping state bits (used on ARM and PA-RISC) */
 74 #define PT_SINGLESTEP_BIT       31
 75 #define PT_SINGLESTEP           (1<<PT_SINGLESTEP_BIT)
 76 #define PT_BLOCKSTEP_BIT        30
 77 #define PT_BLOCKSTEP            (1<<PT_BLOCKSTEP_BIT)
 78 
 79 #include <linux/compiler.h>             /* For unlikely.  */
 80 #include <linux/sched.h>                /* For struct task_struct.  */
 81 
 82 
 83 extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
 84 extern int ptrace_traceme(void);
 85 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 86 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 87 extern int ptrace_attach(struct task_struct *tsk);
 88 extern int ptrace_detach(struct task_struct *, unsigned int);
 89 extern void ptrace_disable(struct task_struct *);
 90 extern int ptrace_check_attach(struct task_struct *task, int kill);
 91 extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
 92 extern void ptrace_notify(int exit_code);
 93 extern void __ptrace_link(struct task_struct *child,
 94                           struct task_struct *new_parent);
 95 extern void __ptrace_unlink(struct task_struct *child);
 96 extern void exit_ptrace(struct task_struct *tracer);
 97 #define PTRACE_MODE_READ   1
 98 #define PTRACE_MODE_ATTACH 2
 99 /* Returns 0 on success, -errno on denial. */
100 extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
101 /* Returns true on success, false on denial. */
102 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
103 
104 static inline int ptrace_reparented(struct task_struct *child)
105 {
106         return child->real_parent != child->parent;
107 }
108 static inline void ptrace_link(struct task_struct *child,
109                                struct task_struct *new_parent)
110 {
111         if (unlikely(child->ptrace))
112                 __ptrace_link(child, new_parent);
113 }
114 static inline void ptrace_unlink(struct task_struct *child)
115 {
116         if (unlikely(child->ptrace))
117                 __ptrace_unlink(child);
118 }
119 
120 int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
121 int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
122 
123 /**
124  * task_ptrace - return %PT_* flags that apply to a task
125  * @task:       pointer to &task_struct in question
126  *
127  * Returns the %PT_* flags that apply to @task.
128  */
129 static inline int task_ptrace(struct task_struct *task)
130 {
131         return task->ptrace;
132 }
133 
134 /**
135  * ptrace_event - possibly stop for a ptrace event notification
136  * @mask:       %PT_* bit to check in @current->ptrace
137  * @event:      %PTRACE_EVENT_* value to report if @mask is set
138  * @message:    value for %PTRACE_GETEVENTMSG to return
139  *
140  * This checks the @mask bit to see if ptrace wants stops for this event.
141  * If so we stop, reporting @event and @message to the ptrace parent.
142  *
143  * Returns nonzero if we did a ptrace notification, zero if not.
144  *
145  * Called without locks.
146  */
147 static inline int ptrace_event(int mask, int event, unsigned long message)
148 {
149         if (mask && likely(!(current->ptrace & mask)))
150                 return 0;
151         current->ptrace_message = message;
152         ptrace_notify((event << 8) | SIGTRAP);
153         return 1;
154 }
155 
156 /**
157  * ptrace_init_task - initialize ptrace state for a new child
158  * @child:              new child task
159  * @ptrace:             true if child should be ptrace'd by parent's tracer
160  *
161  * This is called immediately after adding @child to its parent's children
162  * list.  @ptrace is false in the normal case, and true to ptrace @child.
163  *
164  * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
165  */
166 static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
167 {
168         INIT_LIST_HEAD(&child->ptrace_entry);
169         INIT_LIST_HEAD(&child->ptraced);
170         child->parent = child->real_parent;
171         child->ptrace = 0;
172         if (unlikely(ptrace)) {
173                 child->ptrace = current->ptrace;
174                 ptrace_link(child, current->parent);
175         }
176 }
177 
178 /**
179  * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
180  * @task:       task in %EXIT_DEAD state
181  *
182  * Called with write_lock(&tasklist_lock) held.
183  */
184 static inline void ptrace_release_task(struct task_struct *task)
185 {
186         BUG_ON(!list_empty(&task->ptraced));
187         ptrace_unlink(task);
188         BUG_ON(!list_empty(&task->ptrace_entry));
189 }
190 
191 #ifndef force_successful_syscall_return
192 /*
193  * System call handlers that, upon successful completion, need to return a
194  * negative value should call force_successful_syscall_return() right before
195  * returning.  On architectures where the syscall convention provides for a
196  * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
197  * others), this macro can be used to ensure that the error flag will not get
198  * set.  On architectures which do not support a separate error flag, the macro
199  * is a no-op and the spurious error condition needs to be filtered out by some
200  * other means (e.g., in user-level, by passing an extra argument to the
201  * syscall handler, or something along those lines).
202  */
203 #define force_successful_syscall_return() do { } while (0)
204 #endif
205 
206 /*
207  * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
208  *
209  * These do-nothing inlines are used when the arch does not
210  * implement single-step.  The kerneldoc comments are here
211  * to document the interface for all arch definitions.
212  */
213 
214 #ifndef arch_has_single_step
215 /**
216  * arch_has_single_step - does this CPU support user-mode single-step?
217  *
218  * If this is defined, then there must be function declarations or
219  * inlines for user_enable_single_step() and user_disable_single_step().
220  * arch_has_single_step() should evaluate to nonzero iff the machine
221  * supports instruction single-step for user mode.
222  * It can be a constant or it can test a CPU feature bit.
223  */
224 #define arch_has_single_step()          (0)
225 
226 /**
227  * user_enable_single_step - single-step in user-mode task
228  * @task: either current or a task stopped in %TASK_TRACED
229  *
230  * This can only be called when arch_has_single_step() has returned nonzero.
231  * Set @task so that when it returns to user mode, it will trap after the
232  * next single instruction executes.  If arch_has_block_step() is defined,
233  * this must clear the effects of user_enable_block_step() too.
234  */
235 static inline void user_enable_single_step(struct task_struct *task)
236 {
237         BUG();                  /* This can never be called.  */
238 }
239 
240 /**
241  * user_disable_single_step - cancel user-mode single-step
242  * @task: either current or a task stopped in %TASK_TRACED
243  *
244  * Clear @task of the effects of user_enable_single_step() and
245  * user_enable_block_step().  This can be called whether or not either
246  * of those was ever called on @task, and even if arch_has_single_step()
247  * returned zero.
248  */
249 static inline void user_disable_single_step(struct task_struct *task)
250 {
251 }
252 #endif  /* arch_has_single_step */
253 
254 #ifndef arch_has_block_step
255 /**
256  * arch_has_block_step - does this CPU support user-mode block-step?
257  *
258  * If this is defined, then there must be a function declaration or inline
259  * for user_enable_block_step(), and arch_has_single_step() must be defined
260  * too.  arch_has_block_step() should evaluate to nonzero iff the machine
261  * supports step-until-branch for user mode.  It can be a constant or it
262  * can test a CPU feature bit.
263  */
264 #define arch_has_block_step()           (0)
265 
266 /**
267  * user_enable_block_step - step until branch in user-mode task
268  * @task: either current or a task stopped in %TASK_TRACED
269  *
270  * This can only be called when arch_has_block_step() has returned nonzero,
271  * and will never be called when single-instruction stepping is being used.
272  * Set @task so that when it returns to user mode, it will trap after the
273  * next branch or trap taken.
274  */
275 static inline void user_enable_block_step(struct task_struct *task)
276 {
277         BUG();                  /* This can never be called.  */
278 }
279 #endif  /* arch_has_block_step */
280 
281 #ifndef arch_ptrace_stop_needed
282 /**
283  * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
284  * @code:       current->exit_code value ptrace will stop with
285  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
286  *
287  * This is called with the siglock held, to decide whether or not it's
288  * necessary to release the siglock and call arch_ptrace_stop() with the
289  * same @code and @info arguments.  It can be defined to a constant if
290  * arch_ptrace_stop() is never required, or always is.  On machines where
291  * this makes sense, it should be defined to a quick test to optimize out
292  * calling arch_ptrace_stop() when it would be superfluous.  For example,
293  * if the thread has not been back to user mode since the last stop, the
294  * thread state might indicate that nothing needs to be done.
295  */
296 #define arch_ptrace_stop_needed(code, info)     (0)
297 #endif
298 
299 #ifndef arch_ptrace_stop
300 /**
301  * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
302  * @code:       current->exit_code value ptrace will stop with
303  * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
304  *
305  * This is called with no locks held when arch_ptrace_stop_needed() has
306  * just returned nonzero.  It is allowed to block, e.g. for user memory
307  * access.  The arch can have machine-specific work to be done before
308  * ptrace stops.  On ia64, register backing store gets written back to user
309  * memory here.  Since this can be costly (requires dropping the siglock),
310  * we only do it when the arch requires it for this particular stop, as
311  * indicated by arch_ptrace_stop_needed().
312  */
313 #define arch_ptrace_stop(code, info)            do { } while (0)
314 #endif
315 
316 #ifndef arch_ptrace_untrace
317 /*
318  * Do machine-specific work before untracing child.
319  *
320  * This is called for a normal detach as well as from ptrace_exit()
321  * when the tracing task dies.
322  *
323  * Called with write_lock(&tasklist_lock) held.
324  */
325 #define arch_ptrace_untrace(task)               do { } while (0)
326 #endif
327 
328 extern int task_current_syscall(struct task_struct *target, long *callno,
329                                 unsigned long args[6], unsigned int maxargs,
330                                 unsigned long *sp, unsigned long *pc);
331 
332 #endif
333 
334 #endif
335 
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