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[SPARC64]: More fully work around Spitfire Errata 51.

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It appears that a memory barrier soon after a mispredicted
branch, not just in the delay slot, can cause the hang
condition of this cpu errata.

So move them out-of-line, and explicitly put them into
a "branch always, predict taken" delay slot which should
fully kill this problem.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
2005-08-29 12:46:22 -07:00
parent 442464a500
commit 4f07118f65
14 changed files with 143 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
arch/sparc64/lib/debuglocks.c
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@@ -61,7 +61,7 @@ again:
: "=r" (val)
: "r" (&(lock->lock))
: "memory");
membar("#StoreLoad | #StoreStore");
membar_storeload_storestore();
if (val) {
while (lock->lock) {
if (!--stuck) {
@@ -69,7 +69,7 @@ again:
show(str, lock, caller);
stuck = INIT_STUCK;
}
membar("#LoadLoad");
rmb();
}
goto again;
}
@@ -90,7 +90,7 @@ int _do_spin_trylock(spinlock_t *lock, unsigned long caller)
: "=r" (val)
: "r" (&(lock->lock))
: "memory");
membar("#StoreLoad | #StoreStore");
membar_storeload_storestore();
if (!val) {
lock->owner_pc = ((unsigned int)caller);
lock->owner_cpu = cpu;
@@ -107,7 +107,7 @@ void _do_spin_unlock(spinlock_t *lock)
{
lock->owner_pc = 0;
lock->owner_cpu = NO_PROC_ID;
membar("#StoreStore | #LoadStore");
membar_storestore_loadstore();
lock->lock = 0;
current->thread.smp_lock_count--;
}
@@ -129,7 +129,7 @@ wlock_again:
show_read(str, rw, caller);
stuck = INIT_STUCK;
}
membar("#LoadLoad");
rmb();
}
/* Try once to increment the counter. */
__asm__ __volatile__(
@@ -142,7 +142,7 @@ wlock_again:
"2:" : "=r" (val)
: "0" (&(rw->lock))
: "g1", "g7", "memory");
membar("#StoreLoad | #StoreStore");
membar_storeload_storestore();
if (val)
goto wlock_again;
rw->reader_pc[cpu] = ((unsigned int)caller);
@@ -201,7 +201,7 @@ wlock_again:
show_write(str, rw, caller);
stuck = INIT_STUCK;
}
membar("#LoadLoad");
rmb();
}
/* Try to acuire the write bit. */
@@ -256,7 +256,7 @@ wlock_again:
show_write(str, rw, caller);
stuck = INIT_STUCK;
}
membar("#LoadLoad");
rmb();
}
goto wlock_again;
}