[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>

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
 

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");
 }