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-rw-r--r--arch/sparc64/kernel/smp.c31
-rw-r--r--include/asm-sparc64/mmu_context.h46
-rw-r--r--kernel/fork.c7
3 files changed, 29 insertions, 55 deletions
diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index b137fd63f5e1..a9089e2140e9 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -883,34 +883,13 @@ void smp_flush_tlb_pending(struct mm_struct *mm, unsigned long nr, unsigned long
u32 ctx = CTX_HWBITS(mm->context);
int cpu = get_cpu();
- if (mm == current->active_mm && atomic_read(&mm->mm_users) == 1) {
+ if (mm == current->active_mm && atomic_read(&mm->mm_users) == 1)
mm->cpu_vm_mask = cpumask_of_cpu(cpu);
- goto local_flush_and_out;
- } else {
- /* This optimization is not valid. Normally
- * we will be holding the page_table_lock, but
- * there is an exception which is copy_page_range()
- * when forking. The lock is held during the individual
- * page table updates in the parent, but not at the
- * top level, which is where we are invoked.
- */
- if (0) {
- cpumask_t this_cpu_mask = cpumask_of_cpu(cpu);
-
- /* By virtue of running under the mm->page_table_lock,
- * and mmu_context.h:switch_mm doing the same, the
- * following operation is safe.
- */
- if (cpus_equal(mm->cpu_vm_mask, this_cpu_mask))
- goto local_flush_and_out;
- }
- }
-
- smp_cross_call_masked(&xcall_flush_tlb_pending,
- ctx, nr, (unsigned long) vaddrs,
- mm->cpu_vm_mask);
+ else
+ smp_cross_call_masked(&xcall_flush_tlb_pending,
+ ctx, nr, (unsigned long) vaddrs,
+ mm->cpu_vm_mask);
-local_flush_and_out:
__flush_tlb_pending(ctx, nr, vaddrs);
put_cpu();
diff --git a/include/asm-sparc64/mmu_context.h b/include/asm-sparc64/mmu_context.h
index 87c43c67866e..08ba72d7722c 100644
--- a/include/asm-sparc64/mmu_context.h
+++ b/include/asm-sparc64/mmu_context.h
@@ -87,37 +87,35 @@ extern void __flush_tlb_mm(unsigned long, unsigned long);
static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
{
unsigned long ctx_valid;
+ int cpu;
+ /* Note: page_table_lock is used here to serialize switch_mm
+ * and activate_mm, and their calls to get_new_mmu_context.
+ * This use of page_table_lock is unrelated to its other uses.
+ */
spin_lock(&mm->page_table_lock);
- if (CTX_VALID(mm->context))
- ctx_valid = 1;
- else
- ctx_valid = 0;
+ ctx_valid = CTX_VALID(mm->context);
+ if (!ctx_valid)
+ get_new_mmu_context(mm);
+ spin_unlock(&mm->page_table_lock);
if (!ctx_valid || (old_mm != mm)) {
- if (!ctx_valid)
- get_new_mmu_context(mm);
-
load_secondary_context(mm);
reload_tlbmiss_state(tsk, mm);
}
- {
- int cpu = smp_processor_id();
-
- /* Even if (mm == old_mm) we _must_ check
- * the cpu_vm_mask. If we do not we could
- * corrupt the TLB state because of how
- * smp_flush_tlb_{page,range,mm} on sparc64
- * and lazy tlb switches work. -DaveM
- */
- if (!ctx_valid || !cpu_isset(cpu, mm->cpu_vm_mask)) {
- cpu_set(cpu, mm->cpu_vm_mask);
- __flush_tlb_mm(CTX_HWBITS(mm->context),
- SECONDARY_CONTEXT);
- }
+ /* Even if (mm == old_mm) we _must_ check
+ * the cpu_vm_mask. If we do not we could
+ * corrupt the TLB state because of how
+ * smp_flush_tlb_{page,range,mm} on sparc64
+ * and lazy tlb switches work. -DaveM
+ */
+ cpu = smp_processor_id();
+ if (!ctx_valid || !cpu_isset(cpu, mm->cpu_vm_mask)) {
+ cpu_set(cpu, mm->cpu_vm_mask);
+ __flush_tlb_mm(CTX_HWBITS(mm->context),
+ SECONDARY_CONTEXT);
}
- spin_unlock(&mm->page_table_lock);
}
#define deactivate_mm(tsk,mm) do { } while (0)
@@ -127,6 +125,10 @@ static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm
{
int cpu;
+ /* Note: page_table_lock is used here to serialize switch_mm
+ * and activate_mm, and their calls to get_new_mmu_context.
+ * This use of page_table_lock is unrelated to its other uses.
+ */
spin_lock(&mm->page_table_lock);
if (!CTX_VALID(mm->context))
get_new_mmu_context(mm);
diff --git a/kernel/fork.c b/kernel/fork.c
index efac2c58ec7d..158710d22566 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -470,13 +470,6 @@ static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
if (clone_flags & CLONE_VM) {
atomic_inc(&oldmm->mm_users);
mm = oldmm;
- /*
- * There are cases where the PTL is held to ensure no
- * new threads start up in user mode using an mm, which
- * allows optimizing out ipis; the tlb_gather_mmu code
- * is an example.
- */
- spin_unlock_wait(&oldmm->page_table_lock);
goto good_mm;
}