CRIS v32: Avoid work when switching between tasks with shared memory descriptors in mm/tlb.c
There is no need to do all this work if they share memory descriptors.
Also, fix some minor whitespace and long lines.
diff --git a/arch/cris/arch-v32/mm/tlb.c b/arch/cris/arch-v32/mm/tlb.c
index a076ef6..eda5ebc 100644
--- a/arch/cris/arch-v32/mm/tlb.c
+++ b/arch/cris/arch-v32/mm/tlb.c
@@ -13,8 +13,8 @@
#include <asm/arch/hwregs/supp_reg.h>
#define UPDATE_TLB_SEL_IDX(val) \
-do { \
- unsigned long tlb_sel; \
+do { \
+ unsigned long tlb_sel; \
\
tlb_sel = REG_FIELD(mmu, rw_mm_tlb_sel, idx, val); \
SUPP_REG_WR(RW_MM_TLB_SEL, tlb_sel); \
@@ -30,8 +30,8 @@
* The TLB can host up to 256 different mm contexts at the same time. The running
* context is found in the PID register. Each TLB entry contains a page_id that
* has to match the PID register to give a hit. page_id_map keeps track of which
- * mm is assigned to which page_id, making sure it's known when to invalidate TLB
- * entries.
+ * mm's is assigned to which page_id's, making sure it's known when to
+ * invalidate TLB entries.
*
* The last page_id is never running, it is used as an invalid page_id so that
* it's possible to make TLB entries that will nerver match.
@@ -179,29 +179,29 @@
switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
- int cpu = smp_processor_id();
+ if (prev != next) {
+ int cpu = smp_processor_id();
- /* Make sure there is a MMU context. */
- spin_lock(&mmu_context_lock);
- get_mmu_context(next);
- cpu_set(cpu, next->cpu_vm_mask);
- spin_unlock(&mmu_context_lock);
+ /* Make sure there is a MMU context. */
+ spin_lock(&mmu_context_lock);
+ get_mmu_context(next);
+ cpu_set(cpu, next->cpu_vm_mask);
+ spin_unlock(&mmu_context_lock);
- /*
- * Remember the pgd for the fault handlers. Keep a separate copy of it
- * because current and active_mm might be invalid at points where
- * there's still a need to derefer the pgd.
- */
- per_cpu(current_pgd, cpu) = next->pgd;
+ /*
+ * Remember the pgd for the fault handlers. Keep a seperate
+ * copy of it because current and active_mm might be invalid
+ * at points where * there's still a need to derefer the pgd.
+ */
+ per_cpu(current_pgd, cpu) = next->pgd;
- /* Switch context in the MMU. */
- if (tsk && task_thread_info(tsk))
- {
- SPEC_REG_WR(SPEC_REG_PID, next->context.page_id | task_thread_info(tsk)->tls);
- }
- else
- {
- SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);
- }
+ /* Switch context in the MMU. */
+ if (tsk && task_thread_info(tsk)) {
+ SPEC_REG_WR(SPEC_REG_PID, next->context.page_id |
+ task_thread_info(tsk)->tls);
+ } else {
+ SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);
+ }
+ }
}