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Commit fb7fa8f1 authored by Roland McGrath's avatar Roland McGrath Committed by Ingo Molnar
Browse files

ptrace: arch_has_single_step 



This defines the new macro arch_has_single_step() in linux/ptrace.h, a
default for when asm/ptrace.h does not define it.  It declares the new
user_enable_single_step and user_disable_single_step functions.
This is not used yet, but paves the way to harmonize on this interface
for the arch-specific calls on all machines.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 022eb434

include/linux/ptrace.h

+46 −0
Original line number Diff line number Diff line
@@ -129,6 +129,52 @@ int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data); 
#define force_successful_syscall_return() do { } while (0)

#endif



/*

 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.

 *

 * These do-nothing inlines are used when the arch does not

 * implement single-step.  The kerneldoc comments are here

 * to document the interface for all arch definitions.

 */



#ifndef arch_has_single_step

/**

 * arch_has_single_step - does this CPU support user-mode single-step?

 *

 * If this is defined, then there must be function declarations or

 * inlines for user_enable_single_step() and user_disable_single_step().

 * arch_has_single_step() should evaluate to nonzero iff the machine

 * supports instruction single-step for user mode.

 * It can be a constant or it can test a CPU feature bit.

 */

#define arch_has_single_step()		(0)



/**

 * user_enable_single_step - single-step in user-mode task

 * @task: either current or a task stopped in %TASK_TRACED

 *

 * This can only be called when arch_has_single_step() has returned nonzero.

 * Set @task so that when it returns to user mode, it will trap after the

 * next single instruction executes.

 */

static inline void user_enable_single_step(struct task_struct *task)

{

	BUG();			/* This can never be called.  */

}



/**

 * user_disable_single_step - cancel user-mode single-step

 * @task: either current or a task stopped in %TASK_TRACED

 *

 * Clear @task of the effects of user_enable_single_step().  This can

 * be called whether or not user_enable_single_step() was ever called

 * on @task, and even if arch_has_single_step() returned zero.

 */

static inline void user_disable_single_step(struct task_struct *task)

{

}

#endif	/* arch_has_single_step */



#endif



#endif