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/futex.h b/arch/s390/include/asm/futex.h
index 69cf5b5..a4811aa 100644
--- a/arch/s390/include/asm/futex.h
+++ b/arch/s390/include/asm/futex.h
@@ -29,7 +29,7 @@
int cmparg = (encoded_op << 20) >> 20;
int oldval = 0, newval, ret;
- update_primary_asce(current);
+ load_kernel_asce();
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
@@ -79,7 +79,7 @@
{
int ret;
- update_primary_asce(current);
+ load_kernel_asce();
asm volatile(
" sacf 256\n"
"0: cs %1,%4,0(%5)\n"
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,
diff --git a/arch/s390/include/asm/switch_to.h b/arch/s390/include/asm/switch_to.h
index e759181..29c81f8 100644
--- a/arch/s390/include/asm/switch_to.h
+++ b/arch/s390/include/asm/switch_to.h
@@ -132,7 +132,6 @@
update_cr_regs(next); \
} \
prev = __switch_to(prev,next); \
- update_primary_asce(current); \
} while (0)
#define finish_arch_switch(prev) do { \
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index 50630e6..f3e5cad 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -81,8 +81,7 @@
#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
#define TIF_SIGPENDING 2 /* signal pending */
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
-#define TIF_TLB_WAIT 4 /* wait for TLB flush completion */
-#define TIF_ASCE 5 /* primary asce needs fixup / uaccess */
+#define TIF_ASCE 5 /* user asce needs fixup / uaccess */
#define TIF_PER_TRAP 6 /* deliver sigtrap on return to user */
#define TIF_MCCK_PENDING 7 /* machine check handling is pending */
#define TIF_SYSCALL_TRACE 8 /* syscall trace active */
@@ -99,7 +98,6 @@
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
-#define _TIF_TLB_WAIT (1<<TIF_TLB_WAIT)
#define _TIF_ASCE (1<<TIF_ASCE)
#define _TIF_PER_TRAP (1<<TIF_PER_TRAP)
#define _TIF_MCCK_PENDING (1<<TIF_MCCK_PENDING)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 1662038..7006bfd 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -43,7 +43,7 @@
_TIF_MCCK_PENDING | _TIF_ASCE)
_TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
_TIF_SYSCALL_TRACEPOINT)
-_TIF_TRANSFER = (_TIF_MCCK_PENDING | _TIF_TLB_WAIT)
+_TIF_TRANSFER = (_TIF_MCCK_PENDING | _TIF_ASCE)
STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE = 1 << STACK_SHIFT
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 5963e43..d15e7bf 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -48,7 +48,7 @@
_TIF_MCCK_PENDING | _TIF_ASCE)
_TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
_TIF_SYSCALL_TRACEPOINT)
-_TIF_TRANSFER = (_TIF_MCCK_PENDING | _TIF_TLB_WAIT)
+_TIF_TRANSFER = (_TIF_MCCK_PENDING | _TIF_ASCE)
#define BASED(name) name-system_call(%r13)
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
index 7416efe..53dd5d7 100644
--- a/arch/s390/lib/uaccess.c
+++ b/arch/s390/lib/uaccess.c
@@ -76,7 +76,7 @@
{
unsigned long tmp1, tmp2;
- update_primary_asce(current);
+ load_kernel_asce();
tmp1 = -256UL;
asm volatile(
" sacf 0\n"
@@ -159,7 +159,7 @@
{
unsigned long tmp1, tmp2;
- update_primary_asce(current);
+ load_kernel_asce();
tmp1 = -256UL;
asm volatile(
" sacf 0\n"
@@ -225,7 +225,7 @@
{
unsigned long tmp1;
- update_primary_asce(current);
+ load_kernel_asce();
asm volatile(
" sacf 256\n"
" "AHI" %0,-1\n"
@@ -292,7 +292,7 @@
{
unsigned long tmp1, tmp2;
- update_primary_asce(current);
+ load_kernel_asce();
asm volatile(
" sacf 256\n"
" "AHI" %0,-1\n"
@@ -358,7 +358,7 @@
{
if (unlikely(!size))
return 0;
- update_primary_asce(current);
+ load_kernel_asce();
return strnlen_user_srst(src, size);
}
EXPORT_SYMBOL(__strnlen_user);
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index d7cfd57..7881d4e 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -53,8 +53,10 @@
{
struct mm_struct *mm = arg;
- if (current->active_mm == mm)
- update_user_asce(mm, 1);
+ if (current->active_mm == mm) {
+ clear_user_asce();
+ set_user_asce(mm);
+ }
__tlb_flush_local();
}
@@ -108,7 +110,7 @@
pgd_t *pgd;
if (current->active_mm == mm) {
- clear_user_asce(mm, 1);
+ clear_user_asce();
__tlb_flush_mm(mm);
}
while (mm->context.asce_limit > limit) {
@@ -134,7 +136,7 @@
crst_table_free(mm, (unsigned long *) pgd);
}
if (current->active_mm == mm)
- update_user_asce(mm, 1);
+ set_user_asce(mm);
}
#endif