Commit dc802c2d authored by Roland McGrath's avatar Roland McGrath Committed by Ingo Molnar
Browse files

ptrace: arch_has_block_step 



This defines the new macro arch_has_block_step() in linux/ptrace.h, a
default for when asm/ptrace.h does not define it.  This is the analog
of arch_has_single_step() for step-until-branch on machines that have
it.  It declares the new user_enable_block_step function, which goes
with the existing user_enable_single_step and user_disable_single_step.
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 d9771e8c

include/linux/ptrace.h

+33 −4
Original line number Diff line number Diff line
@@ -155,7 +155,8 @@ int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data); 
 *

 * 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.

 * next single instruction executes.  If arch_has_block_step() is defined,

 * this must clear the effects of user_enable_block_step() too.

 */

static inline void user_enable_single_step(struct task_struct *task)

{
@@ -166,15 +167,43 @@ static inline void user_enable_single_step(struct task_struct *task) 
 * 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.

 * Clear @task of the effects of user_enable_single_step() and

 * user_enable_block_step().  This can be called whether or not either

 * of those 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 */



#ifndef arch_has_block_step

/**

 * arch_has_block_step - does this CPU support user-mode block-step?

 *

 * If this is defined, then there must be a function declaration or inline

 * for user_enable_block_step(), and arch_has_single_step() must be defined

 * too.  arch_has_block_step() should evaluate to nonzero iff the machine

 * supports step-until-branch for user mode.  It can be a constant or it

 * can test a CPU feature bit.

 */

#define arch_has_single_step()		(0)



/**

 * user_enable_block_step - step until branch in user-mode task

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

 *

 * This can only be called when arch_has_block_step() has returned nonzero,

 * and will never be called when single-instruction stepping is being used.

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

 * next branch or trap taken.

 */

static inline void user_enable_block_step(struct task_struct *task)

{

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

}

#endif	/* arch_has_block_step */



#endif



#endif

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