parisc: Align locks for LWS syscalls to L1 cache size (v2)
Align the locks for the Light-weight-syscall (LWS) which are used
for atomic userspace operations (e.g. gcc atomic builtins) on L1 cache
boundaries. This should speed up LWS calls on PA20 systems.
Reported-by: John David Anglin <dave.anglin@xxxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 7ef22e3..80c2306 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -561,9 +561,9 @@ lws_compare_and_swap:
extru %r26, 27, 4, %r20
/* Find lock to use, the hash is either one of 0 to
- 15, multiplied by 16 (keep it 16-byte aligned)
+ 15, multiplied by L1_CACHE_BYTES (keep it L1 cache aligned)
and add to the lock table offset. */
- shlw %r20, 4, %r20
+ shlw %r20, L1_CACHE_SHIFT, %r20
add %r20, %r28, %r20
# if ENABLE_LWS_DEBUG
@@ -751,9 +751,9 @@ cas2_lock_start:
extru %r26, 27, 4, %r20
/* Find lock to use, the hash is either one of 0 to
- 15, multiplied by 16 (keep it 16-byte aligned)
+ 15, multiplied by L1_CACHE_BYTES (keep it L1 cache aligned)
and add to the lock table offset. */
- shlw %r20, 4, %r20
+ shlw %r20, L1_CACHE_SHIFT, %r20
add %r20, %r28, %r20
rsm PSW_SM_I, %r0 /* Disable interrupts */
@@ -931,11 +931,9 @@ END(sys_call_table64)
ENTRY(lws_lock_start)
/* lws locks */
.rept 16
- /* Keep locks aligned at 16-bytes */
+ /* Keep locks aligned to L1_CACHE_BYTES */
.word 1
- .word 0
- .word 0
- .word 0
+ .align L1_CACHE_BYTES
.endr
END(lws_lock_start)
.previous
diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h
index 49df148..47b075c 100644
--- a/arch/parisc/include/asm/futex.h
+++ b/arch/parisc/include/asm/futex.h
@@ -15,7 +15,7 @@ static inline void
_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
{
extern u32 lws_lock_start[];
- long index = ((long)uaddr & 0xf0) >> 2;
+ long index = (((long)uaddr & 0xf0) >> 4) << (L1_CACHE_SHIFT-2);
arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
local_irq_save(*flags);
arch_spin_lock(s);
@@ -25,7 +25,7 @@ static inline void
_futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags)
{
extern u32 lws_lock_start[];
- long index = ((long)uaddr & 0xf0) >> 2;
+ long index = (((long)uaddr & 0xf0) >> 4) << (L1_CACHE_SHIFT-2);
arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
arch_spin_unlock(s);
local_irq_restore(*flags);
--
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