Commit 8d9047f8 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/runtime instrumentation: simplify task exit handling 



Free data structures required for runtime instrumentation from
arch_release_task_struct(). This allows to simplify the code a bit,
and also makes the semantics a bit easier: arch_release_task_struct()
is never called from the task that is being removed.

In addition this allows to get rid of exit_thread() in a later patch.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent d6e646ad

arch/s390/include/asm/runtime_instr.h

+3 −1
Original line number Diff line number Diff line
@@ -85,6 +85,8 @@ static inline void restore_ri_cb(struct runtime_instr_cb *cb_next, 
		load_runtime_instr_cb(&runtime_instr_empty_cb);

}



void exit_thread_runtime_instr(void);

struct task_struct;



void runtime_instr_release(struct task_struct *tsk);



#endif /* _RUNTIME_INSTR_H */

arch/s390/kernel/process.c

+2 −3
Original line number Diff line number Diff line
@@ -48,11 +48,9 @@ extern void kernel_thread_starter(void); 
 */

void exit_thread(struct task_struct *tsk)

{

	if (tsk == current) {

		exit_thread_runtime_instr();

	if (tsk == current)

		exit_thread_gs();

}

}



void flush_thread(void)

{
@@ -60,6 +58,7 @@ void flush_thread(void) 


void arch_release_task_struct(struct task_struct *tsk)

{

	runtime_instr_release(tsk);

}



int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)

arch/s390/kernel/runtime_instr.c

+15 −15
Original line number Diff line number Diff line
@@ -20,11 +20,24 @@ 
/* empty control block to disable RI by loading it */

struct runtime_instr_cb runtime_instr_empty_cb;



void runtime_instr_release(struct task_struct *tsk)

{

	kfree(tsk->thread.ri_cb);

}



static void disable_runtime_instr(void)

{

	struct pt_regs *regs = task_pt_regs(current);

	struct task_struct *task = current;

	struct pt_regs *regs;



	if (!task->thread.ri_cb)

		return;

	regs = task_pt_regs(task);

	preempt_disable();

	load_runtime_instr_cb(&runtime_instr_empty_cb);

	kfree(task->thread.ri_cb);

	task->thread.ri_cb = NULL;

	preempt_enable();



	/*

	 * Make sure the RI bit is deleted from the PSW. If the user did not
@@ -45,19 +58,6 @@ static void init_runtime_instr_cb(struct runtime_instr_cb *cb) 
	cb->valid = 1;

}



void exit_thread_runtime_instr(void)

{

	struct task_struct *task = current;



	preempt_disable();

	if (!task->thread.ri_cb)

		return;

	disable_runtime_instr();

	kfree(task->thread.ri_cb);

	task->thread.ri_cb = NULL;

	preempt_enable();

}



SYSCALL_DEFINE1(s390_runtime_instr, int, command)

{

	struct runtime_instr_cb *cb;
@@ -66,7 +66,7 @@ SYSCALL_DEFINE1(s390_runtime_instr, int, command) 
		return -EOPNOTSUPP;



	if (command == S390_RUNTIME_INSTR_STOP) {

		exit_thread_runtime_instr();

		disable_runtime_instr();

		return 0;

	}

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