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Commit d900bd73 authored by Anton Blanchard's avatar Anton Blanchard Committed by Benjamin Herrenschmidt
Browse files

powerpc/iommu: Fix multiple issues with IOMMU pools code 



There are a number of issues in the recent IOMMU pools code:

- On a preempt kernel we might switch CPUs in the middle of building
  a scatter gather list. When this happens the handle hint passed in
  no longer falls within the local CPU's pool. Check for this and
  fall back to the pool hint.

- We were missing a spin_unlock/spin_lock in one spot where we
  switch pools.

- We need to provide locking around dart_tlb_invalidate_all and
  dart_tlb_invalidate_one now that the global lock is gone.

Reported-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@kernel.org> [v3.6]
parent c8adfecc

arch/powerpc/kernel/iommu.c

+4 −1
Original line number Diff line number Diff line
@@ -215,7 +215,8 @@ static unsigned long iommu_range_alloc(struct device *dev, 
	spin_lock_irqsave(&(pool->lock), flags);



again:

	if ((pass == 0) && handle && *handle)

	if ((pass == 0) && handle && *handle &&

	    (*handle >= pool->start) && (*handle < pool->end))

		start = *handle;

	else

		start = pool->hint;
@@ -236,7 +237,9 @@ static unsigned long iommu_range_alloc(struct device *dev, 
		 * but on second pass, start at 0 in pool 0.

		 */

		if ((start & mask) >= limit || pass > 0) {

			spin_unlock(&(pool->lock));

			pool = &(tbl->pools[0]);

			spin_lock(&(pool->lock));

			start = pool->start;

		} else {

			start &= mask;

arch/powerpc/sysdev/dart_iommu.c

+12 −0
Original line number Diff line number Diff line
@@ -73,11 +73,16 @@ static int dart_is_u4; 


#define DBG(...)



static DEFINE_SPINLOCK(invalidate_lock);



static inline void dart_tlb_invalidate_all(void)

{

	unsigned long l = 0;

	unsigned int reg, inv_bit;

	unsigned long limit;

	unsigned long flags;



	spin_lock_irqsave(&invalidate_lock, flags);



	DBG("dart: flush\n");
@@ -110,12 +115,17 @@ static inline void dart_tlb_invalidate_all(void) 
			panic("DART: TLB did not flush after waiting a long "

			      "time. Buggy U3 ?");

	}



	spin_unlock_irqrestore(&invalidate_lock, flags);

}



static inline void dart_tlb_invalidate_one(unsigned long bus_rpn)

{

	unsigned int reg;

	unsigned int l, limit;

	unsigned long flags;



	spin_lock_irqsave(&invalidate_lock, flags);



	reg = DART_CNTL_U4_ENABLE | DART_CNTL_U4_IONE |

		(bus_rpn & DART_CNTL_U4_IONE_MASK);
@@ -137,6 +147,8 @@ static inline void dart_tlb_invalidate_one(unsigned long bus_rpn) 
			panic("DART: TLB did not flush after waiting a long "

			      "time. Buggy U4 ?");

	}



	spin_unlock_irqrestore(&invalidate_lock, flags);

}



static void dart_flush(struct iommu_table *tbl)