From 331c46591414f7f92b1cec048009abe89892ee79 Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Tue, 7 Mar 2006 21:55:37 -0800 Subject: [PATCH] s390: fix strnlen_user return value strnlen_user is supposed to return then length count + 1 if no terminating \0 is found, and it should return 0 on exception. Found by David Howells . Signed-off-by: Gerald Schaefer Signed-off-by: Heiko Carstens Acked-By: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/lib/uaccess.S | 6 +++--- arch/s390/lib/uaccess64.S | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) (limited to 'arch/s390/lib') diff --git a/arch/s390/lib/uaccess.S b/arch/s390/lib/uaccess.S index 88fc94fe6488..5d59e2625048 100644 --- a/arch/s390/lib/uaccess.S +++ b/arch/s390/lib/uaccess.S @@ -198,12 +198,12 @@ __strnlen_user_asm: 0: srst %r2,%r1 jo 0b sacf 0 - jh 1f # \0 found in string ? ahi %r2,1 # strnlen_user result includes the \0 -1: slr %r2,%r3 + # or return count+1 if \0 not found + slr %r2,%r3 br %r14 2: sacf 0 - lhi %r2,-EFAULT + slr %r2,%r2 # return 0 on exception br %r14 .section __ex_table,"a" .long 0b,2b diff --git a/arch/s390/lib/uaccess64.S b/arch/s390/lib/uaccess64.S index 50219786fc7a..19b41a33c230 100644 --- a/arch/s390/lib/uaccess64.S +++ b/arch/s390/lib/uaccess64.S @@ -194,12 +194,12 @@ __strnlen_user_asm: 0: srst %r2,%r1 jo 0b sacf 0 - jh 1f # \0 found in string ? aghi %r2,1 # strnlen_user result includes the \0 -1: slgr %r2,%r3 + # or return count+1 if \0 not found + slgr %r2,%r3 br %r14 2: sacf 0 - lghi %r2,-EFAULT + slgr %r2,%r2 # return 0 on exception br %r14 .section __ex_table,"a" .quad 0b,2b -- cgit v1.2.1 From 96567161de0ceed45cd2eb0e5380e3c797f5c0f4 Mon Sep 17 00:00:00 2001 From: Christian Ehrhardt Date: Thu, 9 Mar 2006 17:33:49 -0800 Subject: [PATCH] s390: Increase spinlock retry code performance Currently the code tries up to spin_retry times to grab a lock using the cs instruction. The cs instruction has exclusive access to a memory region and therefore invalidates the appropiate cache line of all other cpus. If there is contention on a lock this leads to cache line trashing. This can be avoided if we first check wether a cs instruction is likely to succeed before the instruction gets actually executed. Signed-off-by: Christian Ehrhardt Signed-off-by: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/lib/spinlock.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'arch/s390/lib') diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c index 60f80a4eed4e..b9b7958a226a 100644 --- a/arch/s390/lib/spinlock.c +++ b/arch/s390/lib/spinlock.c @@ -2,8 +2,7 @@ * arch/s390/lib/spinlock.c * Out of line spinlock code. * - * S390 version - * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation + * Copyright (C) IBM Corp. 2004, 2006 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) */ @@ -44,6 +43,8 @@ _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc) _diag44(); count = spin_retry; } + if (__raw_spin_is_locked(lp)) + continue; if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0) return; } @@ -56,6 +57,8 @@ _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc) int count = spin_retry; while (count-- > 0) { + if (__raw_spin_is_locked(lp)) + continue; if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0) return 1; } @@ -74,6 +77,8 @@ _raw_read_lock_wait(raw_rwlock_t *rw) _diag44(); count = spin_retry; } + if (!__raw_read_can_lock(rw)) + continue; old = rw->lock & 0x7fffffffU; if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) return; @@ -88,6 +93,8 @@ _raw_read_trylock_retry(raw_rwlock_t *rw) int count = spin_retry; while (count-- > 0) { + if (!__raw_read_can_lock(rw)) + continue; old = rw->lock & 0x7fffffffU; if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) return 1; @@ -106,6 +113,8 @@ _raw_write_lock_wait(raw_rwlock_t *rw) _diag44(); count = spin_retry; } + if (!__raw_write_can_lock(rw)) + continue; if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) return; } @@ -118,6 +127,8 @@ _raw_write_trylock_retry(raw_rwlock_t *rw) int count = spin_retry; while (count-- > 0) { + if (!__raw_write_can_lock(rw)) + continue; if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) return 1; } -- cgit v1.2.1