Revert "sh: Kill off now redundant local irq disabling."

This reverts commit 64a6d72213dd810dd55bd0a503c36150af41c3c3.

Unfortunately we can't use on_each_cpu() for all of the cache ops, as
some of them only require preempt disabling. This seems to be the same
issue that impacts the mips r4k caches, where this code was based on.
This fixes up a deadlock that showed up in some IRQ context cases.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 35 insertions, 26 deletions

diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index 70fb906419dd..3ac4945cb493 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -48,44 +48,48 @@ static void sh4_flush_icache_range(void *args)
         struct flusher_data *data = args;
         int icacheaddr;
         unsigned long start, end;
-        unsigned long v;
+        unsigned long flags, v;
         int i;
 
         start = data->addr1;
         end = data->addr2;
 
-        /* If there are too many pages then just blow the caches */
-        if (((end - start) >> PAGE_SHIFT) >= MAX_ICACHE_PAGES) {
-                local_flush_cache_all(args);
-        } else {
-                /* selectively flush d-cache then invalidate the i-cache */
-                /* this is inefficient, so only use for small ranges */
-                start &= ~(L1_CACHE_BYTES-1);
-                end += L1_CACHE_BYTES-1;
-                end &= ~(L1_CACHE_BYTES-1);
-
-                jump_to_uncached();
-
-                for (v = start; v < end; v+=L1_CACHE_BYTES) {
-                        __ocbwb(v);
-
-                        icacheaddr = CACHE_IC_ADDRESS_ARRAY |
-                                (v & cpu_data->icache.entry_mask);
-
-                        for (i = 0; i < cpu_data->icache.ways;
-                                i++, icacheaddr += cpu_data->icache.way_incr)
-                                /* Clear i-cache line valid-bit */
-                                ctrl_outl(0, icacheaddr);
-                }
+       /* If there are too many pages then just blow the caches */
+        if (((end - start) >> PAGE_SHIFT) >= MAX_ICACHE_PAGES) {
+                local_flush_cache_all(args);
+       } else {
+               /* selectively flush d-cache then invalidate the i-cache */
+               /* this is inefficient, so only use for small ranges */
+               start &= ~(L1_CACHE_BYTES-1);
+               end += L1_CACHE_BYTES-1;
+               end &= ~(L1_CACHE_BYTES-1);
+
+               local_irq_save(flags);
+               jump_to_uncached();
+
+               for (v = start; v < end; v+=L1_CACHE_BYTES) {
+                       asm volatile("ocbwb     %0"
+                                    : /* no output */
+                                    : "m" (__m(v)));
+
+                       icacheaddr = CACHE_IC_ADDRESS_ARRAY | (
+                                       v & cpu_data->icache.entry_mask);
+
+                       for (i = 0; i < cpu_data->icache.ways;
+                               i++, icacheaddr += cpu_data->icache.way_incr)
+                                       /* Clear i-cache line valid-bit */
+                                       ctrl_outl(0, icacheaddr);
+               }
 
                 back_to_cached();
+                local_irq_restore(flags);
         }
 }
 
 static inline void flush_cache_4096(unsigned long start,
                                     unsigned long phys)
 {
-        unsigned long exec_offset = 0;
+        unsigned long flags, exec_offset = 0;
 
         /*
          * All types of SH-4 require PC to be in P2 to operate on the I-cache.
@@ -95,8 +99,10 @@ static inline void flush_cache_4096(unsigned long start,
             (start < CACHE_OC_ADDRESS_ARRAY))
                 exec_offset = 0x20000000;
 
+        local_irq_save(flags);
         __flush_cache_4096(start | SH_CACHE_ASSOC,
                            P1SEGADDR(phys), exec_offset);
+        local_irq_restore(flags);
 }
 
 /*
@@ -130,8 +136,9 @@ static void sh4_flush_dcache_page(void *arg)
 /* TODO: Selective icache invalidation through IC address array.. */
 static void __uses_jump_to_uncached flush_icache_all(void)
 {
-        unsigned long ccr;
+        unsigned long flags, ccr;
 
+        local_irq_save(flags);
         jump_to_uncached();
 
         /* Flush I-cache */
@@ -143,7 +150,9 @@ static void __uses_jump_to_uncached flush_icache_all(void)
          * back_to_cached() will take care of the barrier for us, don't add
          * another one!
          */
+
         back_to_cached();
+        local_irq_restore(flags);
 }
 
 static inline void flush_dcache_all(void)