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parisc: ensure broadcast tlb purge runs single threaded

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The TLB flushing functions on hppa, which causes PxTLB broadcasts on the system
bus, needs to be protected by irq-safe spinlocks to avoid irq handlers to deadlock
the kernel. The deadlocks only happened during I/O intensive loads and triggered
pretty seldom, which is why this bug went so long unnoticed.

Signed-off-by: Helge Deller <deller@gmx.de>
[edited to use spin_lock_irqsave on UP as well since we'd been locking there
 all this time anyway, --kyle]
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
This commit is contained in:
Helge Deller
2009-06-16 20:51:48 +00:00
committed by Kyle McMartin
parent 84be31be37
commit e82a3b7512
3 changed files with 30 additions and 19 deletions
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14
arch/parisc/include/asm/tlbflush.h
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@@ -12,14 +12,12 @@
* N class systems, only one PxTLB inter processor broadcast can be
* active at any one time on the Merced bus. This tlb purge
* synchronisation is fairly lightweight and harmless so we activate
* it on all SMP systems not just the N class. We also need to have
* preemption disabled on uniprocessor machines, and spin_lock does that
* nicely.
* it on all systems not just the N class.
*/
extern spinlock_t pa_tlb_lock;
#define purge_tlb_start(x) spin_lock(&pa_tlb_lock)
#define purge_tlb_end(x) spin_unlock(&pa_tlb_lock)
#define purge_tlb_start(flags) spin_lock_irqsave(&pa_tlb_lock, flags)
#define purge_tlb_end(flags) spin_unlock_irqrestore(&pa_tlb_lock, flags)
extern void flush_tlb_all(void);
extern void flush_tlb_all_local(void *);
@@ -63,14 +61,16 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
static inline void flush_tlb_page(struct vm_area_struct *vma,
unsigned long addr)
{
unsigned long flags;
/* For one page, it's not worth testing the split_tlb variable */
mb();
mtsp(vma->vm_mm->context,1);
purge_tlb_start();
purge_tlb_start(flags);
pdtlb(addr);
pitlb(addr);
purge_tlb_end();
purge_tlb_end(flags);
}
void __flush_tlb_range(unsigned long sid,