1 files changed, 23 insertions, 24 deletions

diff --git a/arch/arc/include/asm/mmu_context.h b/arch/arc/include/asm/mmu_context.h
index 3a5e6a5b9ed6..9963bb1a5733 100644
--- a/arch/arc/include/asm/mmu_context.h
+++ b/arch/arc/include/asm/mmu_context.h
@@ -15,22 +15,23 @@
 #ifndef _ASM_ARC_MMU_CONTEXT_H
 #define _ASM_ARC_MMU_CONTEXT_H
 
-#include <asm/arcregs.h>
-#include <asm/tlb.h>
 #include <linux/sched/mm.h>
 
+#include <asm/tlb.h>
 #include <asm-generic/mm_hooks.h>
 
-/*		ARC700 ASID Management
+/*		ARC ASID Management
+ *
+ * MMU tags TLBs with an 8-bit ASID, avoiding need to flush the TLB on
+ * context-switch.
  *
- * ARC MMU provides 8-bit ASID (0..255) to TAG TLB entries, allowing entries
- * with same vaddr (different tasks) to co-exit. This provides for
- * "Fast Context Switch" i.e. no TLB flush on ctxt-switch
+ * ASID is managed per cpu, so task threads across CPUs can have different
+ * ASID. Global ASID management is needed if hardware supports TLB shootdown
+ * and/or shared TLB across cores, which ARC doesn't.
  *
- * Linux assigns each task a unique ASID. A simple round-robin allocation
- * of H/w ASID is done using software tracker @asid_cpu.
- * When it reaches max 255, the allocation cycle starts afresh by flushing
- * the entire TLB and wrapping ASID back to zero.
+ * Each task is assigned unique ASID, with a simple round-robin allocator
+ * tracked in @asid_cpu. When 8-bit value rolls over,a new cycle is started
+ * over from 0, and TLB is flushed
  *
  * A new allocation cycle, post rollover, could potentially reassign an ASID
  * to a different task. Thus the rule is to refresh the ASID in a new cycle.
@@ -93,7 +94,7 @@ static inline void get_new_mmu_context(struct mm_struct *mm)
 	asid_mm(mm, cpu) = asid_cpu(cpu);
 
 set_hw:
-	write_aux_reg(ARC_REG_PID, hw_pid(mm, cpu) | MMU_ENABLE);
+	mmu_setup_asid(mm, hw_pid(mm, cpu));
 
 	local_irq_restore(flags);
 }
@@ -102,6 +103,7 @@ set_hw:
  * Initialize the context related info for a new mm_struct
  * instance.
  */
+#define init_new_context init_new_context
 static inline int
 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 {
@@ -113,6 +115,7 @@ init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 	return 0;
 }
 
+#define destroy_context destroy_context
 static inline void destroy_context(struct mm_struct *mm)
 {
 	unsigned long flags;
@@ -144,32 +147,28 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 	 */
 	cpumask_set_cpu(cpu, mm_cpumask(next));
 
-#ifdef ARC_USE_SCRATCH_REG
-	/* PGD cached in MMU reg to avoid 3 mem lookups: task->mm->pgd */
-	write_aux_reg(ARC_REG_SCRATCH_DATA0, next->pgd);
-#endif
+	mmu_setup_pgd(next, next->pgd);
 
 	get_new_mmu_context(next);
 }
 
 /*
- * Called at the time of execve() to get a new ASID
- * Note the subtlety here: get_new_mmu_context() behaves differently here
- * vs. in switch_mm(). Here it always returns a new ASID, because mm has
- * an unallocated "initial" value, while in latter, it moves to a new ASID,
- * only if it was unallocated
+ * activate_mm defaults (in asm-generic) to switch_mm and is called at the
+ * time of execve() to get a new ASID Note the subtlety here:
+ * get_new_mmu_context() behaves differently here vs. in switch_mm(). Here
+ * it always returns a new ASID, because mm has an unallocated "initial"
+ * value, while in latter, it moves to a new ASID, only if it was
+ * unallocated
  */
-#define activate_mm(prev, next)		switch_mm(prev, next, NULL)
 
 /* it seemed that deactivate_mm( ) is a reasonable place to do book-keeping
  * for retiring-mm. However destroy_context( ) still needs to do that because
  * between mm_release( ) = >deactive_mm( ) and
  * mmput => .. => __mmdrop( ) => destroy_context( )
- * there is a good chance that task gets sched-out/in, making it's ASID valid
+ * there is a good chance that task gets sched-out/in, making its ASID valid
  * again (this teased me for a whole day).
  */
-#define deactivate_mm(tsk, mm)   do { } while (0)
 
-#define enter_lazy_tlb(mm, tsk)
+#include <asm-generic/mmu_context.h>
 
 #endif /* __ASM_ARC_MMU_CONTEXT_H */