sh: Fix occasional flush_cache_4096() stack corruption.

IRQs disabling in flush_cache_4096 for cache purge. Under certain
workloads we would get an IRQ in the middle of a purge operation,
and the cachelines would remain in an inconsistent state, leading
to occasional stack corruption.

Signed-off-by: Takeo Takahashi <takahashi.takeo@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 9 insertions, 11 deletions

diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index aa4f62f0e374..e48cc22724d9 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -221,22 +221,20 @@ void flush_cache_sigtramp(unsigned long addr)
 static inline void flush_cache_4096(unsigned long start,
                                     unsigned long phys)
 {
+        unsigned long flags, exec_offset = 0;
+
         /*
          * All types of SH-4 require PC to be in P2 to operate on the I-cache.
          * Some types of SH-4 require PC to be in P2 to operate on the D-cache.
          */
         if ((cpu_data->flags & CPU_HAS_P2_FLUSH_BUG) ||
-            (start < CACHE_OC_ADDRESS_ARRAY)) {
-                unsigned long flags;
-
-                local_irq_save(flags);
-                __flush_cache_4096(start | SH_CACHE_ASSOC,
-                                   P1SEGADDR(phys), 0x20000000);
-                local_irq_restore(flags);
-        } else {
-                __flush_cache_4096(start | SH_CACHE_ASSOC,
-                                   P1SEGADDR(phys), 0);
-        }
+            (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);
 }
 
 /*