[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>

6 files changed, 39 insertions, 28 deletions

diff --git a/arch/sparc64/kernel/pci_iommu.c b/arch/sparc64/kernel/pci_iommu.c
index 2803bc7c2c79..425c60cfea19 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 07424b075938..66255434128a 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 89f5e019f24c..e09ddf927655 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 b1ed23091fbb..aecccd0df1d1 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 b9b42491e118..b4fc6a5462b2 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 0764b9330784..a3ea697f1adb 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);