[SPARC64]: Bulletproof MMU context locking.
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>
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index 9bbd0bf6..a639393 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -639,9 +639,10 @@
{
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 @@
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();
diff --git a/arch/sparc64/mm/tsb.c b/arch/sparc64/mm/tsb.c
index 534ac28..f36799b 100644
--- a/arch/sparc64/mm/tsb.c
+++ b/arch/sparc64/mm/tsb.c
@@ -354,6 +354,7 @@
int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
+ spin_lock_init(&mm->context.lock);
mm->context.sparc64_ctx_val = 0UL;
diff --git a/include/asm-sparc64/mmu_context.h b/include/asm-sparc64/mmu_context.h
index 4be40c5..ca36ea9 100644
--- a/include/asm-sparc64/mmu_context.h
+++ b/include/asm-sparc64/mmu_context.h
@@ -67,14 +67,14 @@
/* Switch the current MM context. Interrupts are disabled. */
static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
{
- unsigned long ctx_valid;
+ unsigned long ctx_valid, flags;
int cpu;
- spin_lock(&mm->context.lock);
+ spin_lock_irqsave(&mm->context.lock, flags);
ctx_valid = CTX_VALID(mm->context);
if (!ctx_valid)
get_new_mmu_context(mm);
- spin_unlock(&mm->context.lock);
+ spin_unlock_irqrestore(&mm->context.lock, flags);
if (!ctx_valid || (old_mm != mm)) {
load_secondary_context(mm);