[ 007/122] powerpc/iommu: Fix multiple issues with IOMMU pools code

Greg Kroah-Hartman
2012-10-10T23:01:03Z

From: Anton Blanchard <anton@samba.org>

commit d900bd7366463fd96a907b2c212242e2b68b27d8 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/kernel/iommu.c | 5 ++++-
arch/powerpc/sysdev/dart_iommu.c | 12 ++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)

--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -215,7 +215,8 @@ static unsigned long iommu_range_alloc(s
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;
--- a/arch/powerpc/sysdev/dart_iommu.c
+++ b/arch/powerpc/sysdev/dart_iommu.c
@@ -74,11 +74,16 @@ 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");

@@ -111,12 +116,17 @@ 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);
@@ -138,6 +148,8 @@ 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)