s390/uaccess: simplify control register updates
Always switch to the kernel ASCE in switch_mm. Load the secondary
space ASCE in finish_arch_post_lock_switch after checking that
any pending page table operations have completed. The primary
ASCE is loaded in entry[64].S. With this the update_primary_asce
call can be removed from the switch_to macro and from the start
of switch_mm function. Remove the load_primary argument from
update_user_asce/clear_user_asce, rename update_user_asce to
set_user_asce and rename update_primary_asce to load_kernel_asce.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 71be346..93ec0c8 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -30,33 +30,31 @@
#define destroy_context(mm) do { } while (0)
-static inline void update_user_asce(struct mm_struct *mm, int load_primary)
+static inline void set_user_asce(struct mm_struct *mm)
{
pgd_t *pgd = mm->pgd;
S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
- if (load_primary)
- __ctl_load(S390_lowcore.user_asce, 1, 1);
set_fs(current->thread.mm_segment);
+ set_thread_flag(TIF_ASCE);
}
-static inline void clear_user_asce(struct mm_struct *mm, int load_primary)
+static inline void clear_user_asce(void)
{
S390_lowcore.user_asce = S390_lowcore.kernel_asce;
- if (load_primary)
- __ctl_load(S390_lowcore.user_asce, 1, 1);
+ __ctl_load(S390_lowcore.user_asce, 1, 1);
__ctl_load(S390_lowcore.user_asce, 7, 7);
}
-static inline void update_primary_asce(struct task_struct *tsk)
+static inline void load_kernel_asce(void)
{
unsigned long asce;
__ctl_store(asce, 1, 1);
if (asce != S390_lowcore.kernel_asce)
__ctl_load(S390_lowcore.kernel_asce, 1, 1);
- set_tsk_thread_flag(tsk, TIF_ASCE);
+ set_thread_flag(TIF_ASCE);
}
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
@@ -64,25 +62,17 @@
{
int cpu = smp_processor_id();
- update_primary_asce(tsk);
if (prev == next)
return;
if (MACHINE_HAS_TLB_LC)
cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
- if (atomic_inc_return(&next->context.attach_count) >> 16) {
- /* Delay update_user_asce until all TLB flushes are done. */
- set_tsk_thread_flag(tsk, TIF_TLB_WAIT);
- /* Clear old ASCE by loading the kernel ASCE. */
- clear_user_asce(next, 0);
- } else {
- cpumask_set_cpu(cpu, mm_cpumask(next));
- update_user_asce(next, 0);
- if (next->context.flush_mm)
- /* Flush pending TLBs */
- __tlb_flush_mm(next);
- }
+ /* Clear old ASCE by loading the kernel ASCE. */
+ __ctl_load(S390_lowcore.kernel_asce, 1, 1);
+ __ctl_load(S390_lowcore.kernel_asce, 7, 7);
+ /* Delay loading of the new ASCE to control registers CR1 & CR7 */
+ set_thread_flag(TIF_ASCE);
+ atomic_inc(&next->context.attach_count);
atomic_dec(&prev->context.attach_count);
- WARN_ON(atomic_read(&prev->context.attach_count) < 0);
if (MACHINE_HAS_TLB_LC)
cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
}
@@ -93,15 +83,14 @@
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
- if (!test_tsk_thread_flag(tsk, TIF_TLB_WAIT))
+ if (!mm)
return;
preempt_disable();
- clear_tsk_thread_flag(tsk, TIF_TLB_WAIT);
while (atomic_read(&mm->context.attach_count) >> 16)
cpu_relax();
cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
- update_user_asce(mm, 0);
+ set_user_asce(mm);
if (mm->context.flush_mm)
__tlb_flush_mm(mm);
preempt_enable();
@@ -113,7 +102,9 @@
static inline void activate_mm(struct mm_struct *prev,
struct mm_struct *next)
{
- switch_mm(prev, next, current);
+ switch_mm(prev, next, current);
+ cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
+ set_user_asce(next);
}
static inline void arch_dup_mmap(struct mm_struct *oldmm,