s390: split TIF bits into CIF, PIF and TIF bits

The oi and ni instructions used in entry[64].S to set and clear bits
in the thread-flags are not guaranteed to be atomic in regard to other
CPUs. Split the TIF bits into CPU, pt_regs and thread-info specific
bits. Updates on the TIF bits are done with atomic instructions,
updates on CPU and pt_regs bits are done with non-atomic instructions.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index dd145321d215..93b9ca42e5c0 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -64,7 +64,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 void arch_cpu_idle(void)
 {
         local_mcck_disable();
-        if (test_thread_flag(TIF_MCCK_PENDING)) {
+        if (test_cpu_flag(CIF_MCCK_PENDING)) {
                 local_mcck_enable();
                 local_irq_enable();
                 return;
@@ -76,7 +76,7 @@ void arch_cpu_idle(void)
 
 void arch_cpu_idle_exit(void)
 {
-        if (test_thread_flag(TIF_MCCK_PENDING))
+        if (test_cpu_flag(CIF_MCCK_PENDING))
                 s390_handle_mcck();
 }
 
@@ -123,7 +123,6 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
         memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
         memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
         clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
-        clear_tsk_thread_flag(p, TIF_PER_TRAP);
         /* Initialize per thread user and system timer values */
         ti = task_thread_info(p);
         ti->user_timer = 0;
@@ -152,6 +151,7 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
         }
         frame->childregs = *current_pt_regs();
         frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
+        frame->childregs.flags = 0;
         if (new_stackp)
                 frame->childregs.gprs[15] = new_stackp;