From 144b9c135b963bcb7f242c7b83bff930620d3161 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Fri, 13 Jan 2006 15:37:17 +1100 Subject: [PATCH] powerpc: use lwsync in atomics, bitops, lock functions eieio is only a store - store ordering. When used to order an unlock operation loads may leak out of the critical region. This is potentially buggy, one example is if a user wants to atomically read a couple of values. We can solve this with an lwsync which orders everything except store - load. I removed the (now unused) EIEIO_ON_SMP macros and the c versions isync_on_smp and eieio_on_smp now we dont use them. I also removed some old comments that were used to identify inline spinlocks in assembly, they dont make sense now our locks are out of line. Another interesting thing was that read_unlock was using an eieio even though the rest of the spinlock code had already been converted to use lwsync. Signed-off-by: Anton Blanchard Signed-off-by: Paul Mackerras --- include/asm-powerpc/futex.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/asm-powerpc/futex.h') diff --git a/include/asm-powerpc/futex.h b/include/asm-powerpc/futex.h index f0319d50b12..39e85f320a7 100644 --- a/include/asm-powerpc/futex.h +++ b/include/asm-powerpc/futex.h @@ -11,7 +11,7 @@ #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ __asm__ __volatile ( \ - SYNC_ON_SMP \ + LWSYNC_ON_SMP \ "1: lwarx %0,0,%2\n" \ insn \ PPC405_ERR77(0, %2) \ -- cgit v1.2.3