From b445e26cbf784cdba10f2b6c3e2cd3ee7bab360a Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 27 Jun 2005 15:42:04 -0700 Subject: [SPARC64]: Avoid membar instructions in delay slots. In particular, avoid membar instructions in the delay slot of a jmpl instruction. UltraSPARC-I, II, IIi, and IIe have a bug, documented in the UltraSPARC-IIi User's Manual, Appendix K, Erratum 51 The long and short of it is that if the IMU unit misses on a branch or jmpl, and there is a store buffer synchronizing membar in the delay slot, the chip can stop fetching instructions. If interrupts are enabled or some other trap is enabled, the chip will unwedge itself, but performance will suffer. We already had a workaround for this bug in a few spots, but it's better to have the entire tree sanitized for this rule. Signed-off-by: David S. Miller --- include/asm-sparc64/rwsem.h | 3 ++- include/asm-sparc64/spinlock.h | 29 +++++++++++++++++++---------- include/asm-sparc64/spitfire.h | 1 - 3 files changed, 21 insertions(+), 12 deletions(-) (limited to 'include') diff --git a/include/asm-sparc64/rwsem.h b/include/asm-sparc64/rwsem.h index bf2ae90ed3d..a1cc94f9598 100644 --- a/include/asm-sparc64/rwsem.h +++ b/include/asm-sparc64/rwsem.h @@ -55,8 +55,9 @@ static __inline__ int rwsem_atomic_update(int delta, struct rw_semaphore *sem) "add %%g1, %1, %%g7\n\t" "cas [%2], %%g1, %%g7\n\t" "cmp %%g1, %%g7\n\t" + "membar #StoreLoad | #StoreStore\n\t" "bne,pn %%icc, 1b\n\t" - " membar #StoreLoad | #StoreStore\n\t" + " nop\n\t" "mov %%g7, %0\n\t" : "=&r" (tmp) : "0" (tmp), "r" (sem) diff --git a/include/asm-sparc64/spinlock.h b/include/asm-sparc64/spinlock.h index db7581bdb53..9cb93a5c2b4 100644 --- a/include/asm-sparc64/spinlock.h +++ b/include/asm-sparc64/spinlock.h @@ -52,12 +52,14 @@ static inline void _raw_spin_lock(spinlock_t *lock) __asm__ __volatile__( "1: ldstub [%1], %0\n" +" membar #StoreLoad | #StoreStore\n" " brnz,pn %0, 2f\n" -" membar #StoreLoad | #StoreStore\n" +" nop\n" " .subsection 2\n" "2: ldub [%1], %0\n" +" membar #LoadLoad\n" " brnz,pt %0, 2b\n" -" membar #LoadLoad\n" +" nop\n" " ba,a,pt %%xcc, 1b\n" " .previous" : "=&r" (tmp) @@ -95,16 +97,18 @@ static inline void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags) __asm__ __volatile__( "1: ldstub [%2], %0\n" -" brnz,pn %0, 2f\n" " membar #StoreLoad | #StoreStore\n" +" brnz,pn %0, 2f\n" +" nop\n" " .subsection 2\n" "2: rdpr %%pil, %1\n" " wrpr %3, %%pil\n" "3: ldub [%2], %0\n" -" brnz,pt %0, 3b\n" " membar #LoadLoad\n" +" brnz,pt %0, 3b\n" +" nop\n" " ba,pt %%xcc, 1b\n" -" wrpr %1, %%pil\n" +" wrpr %1, %%pil\n" " .previous" : "=&r" (tmp1), "=&r" (tmp2) : "r"(lock), "r"(flags) @@ -162,12 +166,14 @@ static void inline __read_lock(rwlock_t *lock) "4: add %0, 1, %1\n" " cas [%2], %0, %1\n" " cmp %0, %1\n" +" membar #StoreLoad | #StoreStore\n" " bne,pn %%icc, 1b\n" -" membar #StoreLoad | #StoreStore\n" +" nop\n" " .subsection 2\n" "2: ldsw [%2], %0\n" +" membar #LoadLoad\n" " brlz,pt %0, 2b\n" -" membar #LoadLoad\n" +" nop\n" " ba,a,pt %%xcc, 4b\n" " .previous" : "=&r" (tmp1), "=&r" (tmp2) @@ -204,12 +210,14 @@ static void inline __write_lock(rwlock_t *lock) "4: or %0, %3, %1\n" " cas [%2], %0, %1\n" " cmp %0, %1\n" +" membar #StoreLoad | #StoreStore\n" " bne,pn %%icc, 1b\n" -" membar #StoreLoad | #StoreStore\n" +" nop\n" " .subsection 2\n" "2: lduw [%2], %0\n" +" membar #LoadLoad\n" " brnz,pt %0, 2b\n" -" membar #LoadLoad\n" +" nop\n" " ba,a,pt %%xcc, 4b\n" " .previous" : "=&r" (tmp1), "=&r" (tmp2) @@ -240,8 +248,9 @@ static int inline __write_trylock(rwlock_t *lock) " or %0, %4, %1\n" " cas [%3], %0, %1\n" " cmp %0, %1\n" +" membar #StoreLoad | #StoreStore\n" " bne,pn %%icc, 1b\n" -" membar #StoreLoad | #StoreStore\n" +" nop\n" " mov 1, %2\n" "2:" : "=&r" (tmp1), "=&r" (tmp2), "=&r" (result) diff --git a/include/asm-sparc64/spitfire.h b/include/asm-sparc64/spitfire.h index 9d7613eea81..1aa932773af 100644 --- a/include/asm-sparc64/spitfire.h +++ b/include/asm-sparc64/spitfire.h @@ -111,7 +111,6 @@ static __inline__ void spitfire_put_dcache_tag(unsigned long addr, unsigned long "membar #Sync" : /* No outputs */ : "r" (tag), "r" (addr), "i" (ASI_DCACHE_TAG)); - __asm__ __volatile__ ("membar #Sync" : : : "memory"); } /* The instruction cache lines are flushed with this, but note that -- cgit v1.2.3