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authorDavid S. Miller <davem@davemloft.net>2005-08-29 12:46:22 -0700
committerDavid S. Miller <davem@davemloft.net>2005-08-29 12:46:22 -0700
commit4f07118f656c179740cad35b827032e2e29b1210 (patch)
tree7ddeb17346fe25ae75aa5373659c053afb9ef5f5 /arch
parent442464a50077ff00454ff8d7628cbe1b8eacc034 (diff)
[SPARC64]: More fully work around Spitfire Errata 51.
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/sparc64/kernel/pci_iommu.c2
-rw-r--r--arch/sparc64/kernel/process.c2
-rw-r--r--arch/sparc64/kernel/sbus.c2
-rw-r--r--arch/sparc64/kernel/signal32.c22
-rw-r--r--arch/sparc64/kernel/smp.c30
-rw-r--r--arch/sparc64/kernel/sparc64_ksyms.c9
-rw-r--r--arch/sparc64/lib/Makefile2
-rw-r--r--arch/sparc64/lib/debuglocks.c16
-rw-r--r--arch/sparc64/lib/mb.S73
-rw-r--r--arch/sparc64/solaris/misc.c6
10 files changed, 125 insertions, 39 deletions
diff --git a/arch/sparc64/kernel/pci_iommu.c b/arch/sparc64/kernel/pci_iommu.c
index 2803bc7c2c7..425c60cfea1 100644
--- a/arch/sparc64/kernel/pci_iommu.c
+++ b/arch/sparc64/kernel/pci_iommu.c
@@ -466,7 +466,7 @@ do_flush_sync:
if (!limit)
break;
udelay(1);
- membar("#LoadLoad");
+ rmb();
}
if (!limit)
printk(KERN_WARNING "pci_strbuf_flush: flushflag timeout "
diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
index 07424b07593..66255434128 100644
--- a/arch/sparc64/kernel/process.c
+++ b/arch/sparc64/kernel/process.c
@@ -103,7 +103,7 @@ void cpu_idle(void)
* other cpus see our increasing idleness for the buddy
* redistribution algorithm. -DaveM
*/
- membar("#StoreStore | #StoreLoad");
+ membar_storeload_storestore();
}
}
diff --git a/arch/sparc64/kernel/sbus.c b/arch/sparc64/kernel/sbus.c
index 89f5e019f24..e09ddf92765 100644
--- a/arch/sparc64/kernel/sbus.c
+++ b/arch/sparc64/kernel/sbus.c
@@ -147,7 +147,7 @@ static void sbus_strbuf_flush(struct sbus_iommu *iommu, u32 base, unsigned long
if (!limit)
break;
udelay(1);
- membar("#LoadLoad");
+ rmb();
}
if (!limit)
printk(KERN_WARNING "sbus_strbuf_flush: flushflag timeout "
diff --git a/arch/sparc64/kernel/signal32.c b/arch/sparc64/kernel/signal32.c
index b1ed23091fb..aecccd0df1d 100644
--- a/arch/sparc64/kernel/signal32.c
+++ b/arch/sparc64/kernel/signal32.c
@@ -877,11 +877,12 @@ static void new_setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
unsigned long page = (unsigned long)
page_address(pte_page(*ptep));
- __asm__ __volatile__(
- " membar #StoreStore\n"
- " flush %0 + %1"
- : : "r" (page), "r" (address & (PAGE_SIZE - 1))
- : "memory");
+ wmb();
+ __asm__ __volatile__("flush %0 + %1"
+ : /* no outputs */
+ : "r" (page),
+ "r" (address & (PAGE_SIZE - 1))
+ : "memory");
}
pte_unmap(ptep);
preempt_enable();
@@ -1292,11 +1293,12 @@ static void setup_rt_frame32(struct k_sigaction *ka, struct pt_regs *regs,
unsigned long page = (unsigned long)
page_address(pte_page(*ptep));
- __asm__ __volatile__(
- " membar #StoreStore\n"
- " flush %0 + %1"
- : : "r" (page), "r" (address & (PAGE_SIZE - 1))
- : "memory");
+ wmb();
+ __asm__ __volatile__("flush %0 + %1"
+ : /* no outputs */
+ : "r" (page),
+ "r" (address & (PAGE_SIZE - 1))
+ : "memory");
}
pte_unmap(ptep);
preempt_enable();
diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index b9b42491e11..b4fc6a5462b 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -144,7 +144,7 @@ void __init smp_callin(void)
current->active_mm = &init_mm;
while (!cpu_isset(cpuid, smp_commenced_mask))
- membar("#LoadLoad");
+ rmb();
cpu_set(cpuid, cpu_online_map);
}
@@ -184,11 +184,11 @@ static inline long get_delta (long *rt, long *master)
for (i = 0; i < NUM_ITERS; i++) {
t0 = tick_ops->get_tick();
go[MASTER] = 1;
- membar("#StoreLoad");
+ membar_storeload();
while (!(tm = go[SLAVE]))
- membar("#LoadLoad");
+ rmb();
go[SLAVE] = 0;
- membar("#StoreStore");
+ wmb();
t1 = tick_ops->get_tick();
if (t1 - t0 < best_t1 - best_t0)
@@ -221,7 +221,7 @@ void smp_synchronize_tick_client(void)
go[MASTER] = 1;
while (go[MASTER])
- membar("#LoadLoad");
+ rmb();
local_irq_save(flags);
{
@@ -273,21 +273,21 @@ static void smp_synchronize_one_tick(int cpu)
/* wait for client to be ready */
while (!go[MASTER])
- membar("#LoadLoad");
+ rmb();
/* now let the client proceed into his loop */
go[MASTER] = 0;
- membar("#StoreLoad");
+ membar_storeload();
spin_lock_irqsave(&itc_sync_lock, flags);
{
for (i = 0; i < NUM_ROUNDS*NUM_ITERS; i++) {
while (!go[MASTER])
- membar("#LoadLoad");
+ rmb();
go[MASTER] = 0;
- membar("#StoreStore");
+ wmb();
go[SLAVE] = tick_ops->get_tick();
- membar("#StoreLoad");
+ membar_storeload();
}
}
spin_unlock_irqrestore(&itc_sync_lock, flags);
@@ -927,11 +927,11 @@ void smp_capture(void)
smp_processor_id());
#endif
penguins_are_doing_time = 1;
- membar("#StoreStore | #LoadStore");
+ membar_storestore_loadstore();
atomic_inc(&smp_capture_registry);
smp_cross_call(&xcall_capture, 0, 0, 0);
while (atomic_read(&smp_capture_registry) != ncpus)
- membar("#LoadLoad");
+ rmb();
#ifdef CAPTURE_DEBUG
printk("done\n");
#endif
@@ -947,7 +947,7 @@ void smp_release(void)
smp_processor_id());
#endif
penguins_are_doing_time = 0;
- membar("#StoreStore | #StoreLoad");
+ membar_storeload_storestore();
atomic_dec(&smp_capture_registry);
}
}
@@ -970,9 +970,9 @@ void smp_penguin_jailcell(int irq, struct pt_regs *regs)
save_alternate_globals(global_save);
prom_world(1);
atomic_inc(&smp_capture_registry);
- membar("#StoreLoad | #StoreStore");
+ membar_storeload_storestore();
while (penguins_are_doing_time)
- membar("#LoadLoad");
+ rmb();
restore_alternate_globals(global_save);
atomic_dec(&smp_capture_registry);
prom_world(0);
diff --git a/arch/sparc64/kernel/sparc64_ksyms.c b/arch/sparc64/kernel/sparc64_ksyms.c
index 0764b933078..a3ea697f1ad 100644
--- a/arch/sparc64/kernel/sparc64_ksyms.c
+++ b/arch/sparc64/kernel/sparc64_ksyms.c
@@ -406,3 +406,12 @@ EXPORT_SYMBOL(xor_vis_4);
EXPORT_SYMBOL(xor_vis_5);
EXPORT_SYMBOL(prom_palette);
+
+/* memory barriers */
+EXPORT_SYMBOL(mb);
+EXPORT_SYMBOL(rmb);
+EXPORT_SYMBOL(wmb);
+EXPORT_SYMBOL(membar_storeload);
+EXPORT_SYMBOL(membar_storeload_storestore);
+EXPORT_SYMBOL(membar_storeload_loadload);
+EXPORT_SYMBOL(membar_storestore_loadstore);
diff --git a/arch/sparc64/lib/Makefile b/arch/sparc64/lib/Makefile
index 40dbeec7e5d..6201f104098 100644
--- a/arch/sparc64/lib/Makefile
+++ b/arch/sparc64/lib/Makefile
@@ -12,7 +12,7 @@ lib-y := PeeCeeI.o copy_page.o clear_page.o strlen.o strncmp.o \
U1memcpy.o U1copy_from_user.o U1copy_to_user.o \
U3memcpy.o U3copy_from_user.o U3copy_to_user.o U3patch.o \
copy_in_user.o user_fixup.o memmove.o \
- mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o
+ mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o mb.o
lib-$(CONFIG_DEBUG_SPINLOCK) += debuglocks.o
lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
diff --git a/arch/sparc64/lib/debuglocks.c b/arch/sparc64/lib/debuglocks.c
index 7f6ccc4114c..f5f0b5586f0 100644
--- a/arch/sparc64/lib/debuglocks.c
+++ b/arch/sparc64/lib/debuglocks.c
@@ -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;
}
diff --git a/arch/sparc64/lib/mb.S b/arch/sparc64/lib/mb.S
new file mode 100644
index 00000000000..4004f748619
--- /dev/null
+++ b/arch/sparc64/lib/mb.S
@@ -0,0 +1,73 @@
+/* mb.S: Out of line memory barriers.
+ *
+ * Copyright (C) 2005 David S. Miller (davem@davemloft.net)
+ */
+
+ /* These are here in an effort to more fully work around
+ * Spitfire Errata #51. Essentially, if a memory barrier
+ * occurs soon after a mispredicted branch, the chip can stop
+ * executing instructions until a trap occurs. Therefore, if
+ * interrupts are disabled, the chip can hang forever.
+ *
+ * It used to be believed that the memory barrier had to be
+ * right in the delay slot, but a case has been traced
+ * recently wherein the memory barrier was one instruction
+ * after the branch delay slot and the chip still hung. The
+ * offending sequence was the following in sym_wakeup_done()
+ * of the sym53c8xx_2 driver:
+ *
+ * call sym_ccb_from_dsa, 0
+ * movge %icc, 0, %l0
+ * brz,pn %o0, .LL1303
+ * mov %o0, %l2
+ * membar #LoadLoad
+ *
+ * The branch has to be mispredicted for the bug to occur.
+ * Therefore, we put the memory barrier explicitly into a
+ * "branch always, predicted taken" delay slot to avoid the
+ * problem case.
+ */
+
+ .text
+
+99: retl
+ nop
+
+ .globl mb
+mb: ba,pt %xcc, 99b
+ membar #LoadLoad | #LoadStore | #StoreStore | #StoreLoad
+ .size mb, .-mb
+
+ .globl rmb
+rmb: ba,pt %xcc, 99b
+ membar #LoadLoad
+ .size rmb, .-rmb
+
+ .globl wmb
+wmb: ba,pt %xcc, 99b
+ membar #StoreStore
+ .size wmb, .-wmb
+
+ .globl membar_storeload
+membar_storeload:
+ ba,pt %xcc, 99b
+ membar #StoreLoad
+ .size membar_storeload, .-membar_storeload
+
+ .globl membar_storeload_storestore
+membar_storeload_storestore:
+ ba,pt %xcc, 99b
+ membar #StoreLoad | #StoreStore
+ .size membar_storeload_storestore, .-membar_storeload_storestore
+
+ .globl membar_storeload_loadload
+membar_storeload_loadload:
+ ba,pt %xcc, 99b
+ membar #StoreLoad | #LoadLoad
+ .size membar_storeload_loadload, .-membar_storeload_loadload
+
+ .globl membar_storestore_loadstore
+membar_storestore_loadstore:
+ ba,pt %xcc, 99b
+ membar #StoreStore | #LoadStore
+ .size membar_storestore_loadstore, .-membar_storestore_loadstore
diff --git a/arch/sparc64/solaris/misc.c b/arch/sparc64/solaris/misc.c
index 15b4cfe0755..302efbcba70 100644
--- a/arch/sparc64/solaris/misc.c
+++ b/arch/sparc64/solaris/misc.c
@@ -737,7 +737,8 @@ MODULE_LICENSE("GPL");
extern u32 tl0_solaris[8];
#define update_ttable(x) \
tl0_solaris[3] = (((long)(x) - (long)tl0_solaris - 3) >> 2) | 0x40000000; \
- __asm__ __volatile__ ("membar #StoreStore; flush %0" : : "r" (&tl0_solaris[3]))
+ wmb(); \
+ __asm__ __volatile__ ("flush %0" : : "r" (&tl0_solaris[3]))
#else
#endif
@@ -761,7 +762,8 @@ int init_module(void)
entry64_personality_patch |=
(offsetof(struct task_struct, personality) +
(sizeof(unsigned long) - 1));
- __asm__ __volatile__("membar #StoreStore; flush %0"
+ wmb();
+ __asm__ __volatile__("flush %0"
: : "r" (&entry64_personality_patch));
return 0;
}