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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: Alexander Graf <agraf@suse.de>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@kernel.org> [v3.6]
This commit is contained in:
Anton Blanchard 2012-10-03 18:57:10 +00:00 committed by Benjamin Herrenschmidt
parent c8adfeccee
commit d900bd7366
2 changed files with 16 additions and 1 deletions
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5
arch/powerpc/kernel/iommu.c
View File

@ -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 @@ again:
* 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;

12
arch/powerpc/sysdev/dart_iommu.c
View File

@ -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 @@ retry:
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 @@ wait_more:
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)