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s390/runtime instrumentation: simplify task exit handling

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commit 8d9047f8b9 upstream.

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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heiko Carstens 2017-09-11 11:24:22 +02:00 committed by Greg Kroah-Hartman
parent 955c907b97
commit b8e212c599
3 changed files with 20 additions and 19 deletions
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4
arch/s390/include/asm/runtime_instr.h
View file

@ -86,6 +86,8 @@ 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 */

5
arch/s390/kernel/process.c
View file

@ -49,10 +49,8 @@ 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)
@ -65,6 +63,7 @@ void release_thread(struct task_struct *dead_task)
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)

30
arch/s390/kernel/runtime_instr.c
View file

@ -21,11 +21,24 @@
/* 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
@ -46,19 +59,6 @@ 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;
@ -67,7 +67,7 @@ SYSCALL_DEFINE1(s390_runtime_instr, int, command)
return -EOPNOTSUPP;
if (command == S390_RUNTIME_INSTR_STOP) {
exit_thread_runtime_instr();
disable_runtime_instr();
return 0;
}