[PATCH 3.16 148/192] sparc64: Take ctx_alloc_lock properly in hugetlb_setup().

Ben Hutchings
2017-10-09T13:53:42Z

From: "David S. Miller" <davem@davemloft.net>

[ Upstream commit 9ea46abe22550e3366ff7cee2f8391b35b12f730 ]

On cheetahplus chips we take the ctx_alloc_lock in order to
modify the TLB lookup parameters for the indexed TLBs, which
are stored in the context register.

This is called with interrupts disabled, however ctx_alloc_lock
is an IRQ safe lock, therefore we must take acquire/release it
properly with spin_{lock,unlock}_irq().

Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/sparc/mm/init_64.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2682,9 +2682,10 @@ void hugetlb_setup(struct pt_regs *regs)
* the Data-TLB for huge pages.
*/
if (tlb_type == cheetah_plus) {
+ bool need_context_reload = false;
unsigned long ctx;

- spin_lock(&ctx_alloc_lock);
+ spin_lock_irq(&ctx_alloc_lock);
ctx = mm->context.sparc64_ctx_val;
ctx &= ~CTX_PGSZ_MASK;
ctx |= CTX_PGSZ_BASE << CTX_PGSZ0_SHIFT;
@@ -2703,9 +2704,12 @@ void hugetlb_setup(struct pt_regs *regs)
* also executing in this address space.
*/
mm->context.sparc64_ctx_val = ctx;
- on_each_cpu(context_reload, mm, 0);
+ need_context_reload = true;
}
- spin_unlock(&ctx_alloc_lock);
+ spin_unlock_irq(&ctx_alloc_lock);
+
+ if (need_context_reload)
+ on_each_cpu(context_reload, mm, 0);
}
}
#endif