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[SPARC64]: Bulletproof MMU context locking.

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1) Always spin_lock_init() in init_context().  The caller essentially
   clears it out, or copies the mm info from the parent.  In both
   cases we need to explicitly initialize the spinlock.

2) Always do explicit IRQ disabling while taking mm->context.lock
   and ctx_alloc_lock.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
2006-03-06 19:59:50 -08:00
parent 9132983ae1
commit a77754b4d0
3 changed files with 7 additions and 5 deletions
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5
arch/sparc64/mm/init.c
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@@ -639,9 +639,10 @@ void get_new_mmu_context(struct mm_struct *mm)
{
unsigned long ctx, new_ctx;
unsigned long orig_pgsz_bits;
unsigned long flags;
int new_version;
spin_lock(&ctx_alloc_lock);
spin_lock_irqsave(&ctx_alloc_lock, flags);
orig_pgsz_bits = (mm->context.sparc64_ctx_val & CTX_PGSZ_MASK);
ctx = (tlb_context_cache + 1) & CTX_NR_MASK;
new_ctx = find_next_zero_bit(mmu_context_bmap, 1 << CTX_NR_BITS, ctx);
@@ -677,7 +678,7 @@ void get_new_mmu_context(struct mm_struct *mm)
out:
tlb_context_cache = new_ctx;
mm->context.sparc64_ctx_val = new_ctx | orig_pgsz_bits;
spin_unlock(&ctx_alloc_lock);
spin_unlock_irqrestore(&ctx_alloc_lock, flags);
if (unlikely(new_version))
smp_new_mmu_context_version();