[ARM] 3356/1: Workaround for the ARM1136 I-cache invalidation problem

Patch from Catalin Marinas

ARM1136 erratum 371025 (category 2) specifies that, under rare
conditions, an invalidate I-cache by MVA (line or range) operation can
fail to invalidate a cache line. The recommended workaround is to
either invalidate the entire I-cache or invalidate the range by
set/way rather than MVA.

Note that for a 16K cache size, invalidating a 4K page by set/way is
equivalent to invalidating the entire I-cache.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 8 insertions, 5 deletions

diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S
index d921c1024ae0..2c6c2a7c05a0 100644
--- a/arch/arm/mm/cache-v6.S
+++ b/arch/arm/mm/cache-v6.S
@@ -96,15 +96,16 @@ ENTRY(v6_coherent_user_range)
 #ifdef HARVARD_CACHE
         bic     r0, r0, #CACHE_LINE_SIZE - 1
 1:      mcr     p15, 0, r0, c7, c10, 1          @ clean D line
-        mcr     p15, 0, r0, c7, c5, 1           @ invalidate I line
         add     r0, r0, #CACHE_LINE_SIZE
         cmp     r0, r1
         blo     1b
 #endif
-        mcr     p15, 0, r0, c7, c5, 6           @ invalidate BTB
-#ifdef HARVARD_CACHE
         mov     r0, #0
+#ifdef HARVARD_CACHE
         mcr     p15, 0, r0, c7, c10, 4          @ drain write buffer
+        mcr     p15, 0, r0, c7, c5, 0           @ I+BTB cache invalidate
+#else
+        mcr     p15, 0, r0, c7, c5, 6           @ invalidate BTB
 #endif
         mov     pc, lr
 
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 330695b6b19d..b103e56806bd 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -24,14 +24,16 @@
 static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
 {
         unsigned long to = ALIAS_FLUSH_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
+        const int zero = 0;
 
         set_pte(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL));
         flush_tlb_kernel_page(to);
 
         asm(    "mcrr   p15, 0, %1, %0, c14\n"
-        "       mcrr    p15, 0, %1, %0, c5\n"
+        "       mcr     p15, 0, %2, c7, c10, 4\n"
+        "       mcr     p15, 0, %2, c7, c5, 0\n"
             :
-            : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES)
+            : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
             : "cc");
 }