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authorVineet Gupta <vgupta@synopsys.com>2013-08-23 19:16:34 +0530
committerVineet Gupta <vgupta@synopsys.com>2013-11-06 10:41:45 +0530
commit63eca94ca206e342bad4a06a86d8e7eda3053a4e (patch)
tree8037367b1c0a2d428ad5add62c842223eb290520 /arch/arc/include/asm
parentb6fe8e7c0189d017fdba90d1cd134337098c19c3 (diff)
ARC: [SMP] ASID allocation
-Track a Per CPU ASID counter -mm-per-cpu ASID (multiple threads, or mm migrated around) Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/include/asm')
-rw-r--r--arch/arc/include/asm/mmu.h2
-rw-r--r--arch/arc/include/asm/mmu_context.h44
2 files changed, 29 insertions, 17 deletions
diff --git a/arch/arc/include/asm/mmu.h b/arch/arc/include/asm/mmu.h
index c2663b32866b..8c84ae98c337 100644
--- a/arch/arc/include/asm/mmu.h
+++ b/arch/arc/include/asm/mmu.h
@@ -48,7 +48,7 @@
#ifndef __ASSEMBLY__
typedef struct {
- unsigned long asid; /* 8 bit MMU PID + Generation cycle */
+ unsigned long asid[NR_CPUS]; /* 8 bit MMU PID + Generation cycle */
} mm_context_t;
#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
diff --git a/arch/arc/include/asm/mmu_context.h b/arch/arc/include/asm/mmu_context.h
index 43a1b51bb8cc..45f06f566b02 100644
--- a/arch/arc/include/asm/mmu_context.h
+++ b/arch/arc/include/asm/mmu_context.h
@@ -30,13 +30,13 @@
* "Fast Context Switch" i.e. no TLB flush on ctxt-switch
*
* Linux assigns each task a unique ASID. A simple round-robin allocation
- * of H/w ASID is done using software tracker @asid_cache.
+ * 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.
*
* 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.
- * The 32 bit @asid_cache (and mm->asid) have 8 bits MMU PID and rest 24 bits
+ * The 32 bit @asid_cpu (and mm->asid) have 8 bits MMU PID and rest 24 bits
* serve as cycle/generation indicator and natural 32 bit unsigned math
* automagically increments the generation when lower 8 bits rollover.
*/
@@ -47,9 +47,11 @@
#define MM_CTXT_FIRST_CYCLE (MM_CTXT_ASID_MASK + 1)
#define MM_CTXT_NO_ASID 0UL
-#define hw_pid(mm) (mm->context.asid & MM_CTXT_ASID_MASK)
+#define asid_mm(mm, cpu) mm->context.asid[cpu]
+#define hw_pid(mm, cpu) (asid_mm(mm, cpu) & MM_CTXT_ASID_MASK)
-extern unsigned int asid_cache;
+DECLARE_PER_CPU(unsigned int, asid_cache);
+#define asid_cpu(cpu) per_cpu(asid_cache, cpu)
/*
* Get a new ASID if task doesn't have a valid one (unalloc or from prev cycle)
@@ -57,6 +59,7 @@ extern unsigned int asid_cache;
*/
static inline void get_new_mmu_context(struct mm_struct *mm)
{
+ const unsigned int cpu = smp_processor_id();
unsigned long flags;
local_irq_save(flags);
@@ -71,11 +74,11 @@ static inline void get_new_mmu_context(struct mm_struct *mm)
* first need to destroy the context, setting it to invalid
* value.
*/
- if (!((mm->context.asid ^ asid_cache) & MM_CTXT_CYCLE_MASK))
+ if (!((asid_mm(mm, cpu) ^ asid_cpu(cpu)) & MM_CTXT_CYCLE_MASK))
goto set_hw;
/* move to new ASID and handle rollover */
- if (unlikely(!(++asid_cache & MM_CTXT_ASID_MASK))) {
+ if (unlikely(!(++asid_cpu(cpu) & MM_CTXT_ASID_MASK))) {
flush_tlb_all();
@@ -84,15 +87,15 @@ static inline void get_new_mmu_context(struct mm_struct *mm)
* If the container itself wrapped around, set it to a non zero
* "generation" to distinguish from no context
*/
- if (!asid_cache)
- asid_cache = MM_CTXT_FIRST_CYCLE;
+ if (!asid_cpu(cpu))
+ asid_cpu(cpu) = MM_CTXT_FIRST_CYCLE;
}
/* Assign new ASID to tsk */
- mm->context.asid = asid_cache;
+ asid_mm(mm, cpu) = asid_cpu(cpu);
set_hw:
- write_aux_reg(ARC_REG_PID, hw_pid(mm) | MMU_ENABLE);
+ write_aux_reg(ARC_REG_PID, hw_pid(mm, cpu) | MMU_ENABLE);
local_irq_restore(flags);
}
@@ -104,10 +107,24 @@ set_hw:
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
- mm->context.asid = MM_CTXT_NO_ASID;
+ int i;
+
+ for_each_possible_cpu(i)
+ asid_mm(mm, i) = MM_CTXT_NO_ASID;
+
return 0;
}
+static inline void destroy_context(struct mm_struct *mm)
+{
+ unsigned long flags;
+
+ /* Needed to elide CONFIG_DEBUG_PREEMPT warning */
+ local_irq_save(flags);
+ asid_mm(mm, smp_processor_id()) = MM_CTXT_NO_ASID;
+ local_irq_restore(flags);
+}
+
/* Prepare the MMU for task: setup PID reg with allocated ASID
If task doesn't have an ASID (never alloc or stolen, get a new ASID)
*/
@@ -131,11 +148,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
#define activate_mm(prev, next) switch_mm(prev, next, NULL)
-static inline void destroy_context(struct mm_struct *mm)
-{
- mm->context.asid = MM_CTXT_NO_ASID;
-}
-
/* 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