[patch 17/49] ARM: xsc3: fix xsc3_l2_inv_range

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: arm-xsc3-fix-xsc3_l2_inv_range.patch --]
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2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Dan Williams <dan.j.williams@intel.com>

commit c7cf72dcadbe39c2077b32460f86c9f8167be3be upstream

When 'start' and 'end' are less than a cacheline apart and 'start' is
unaligned we are done after cleaning and invalidating the first
cacheline.  So check for (start < end) which will not walk off into
invalid address ranges when (start > end).

This issue was caught by drivers/dma/dmatest.

2.6.27 is susceptible.

Cc: <stable@kernel.org>
Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: Lothar Wafmann <LW@KARO-electronics.de>
Cc: Lennert Buytenhek <buytenh@marvell.com>
Cc: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 arch/arm/mm/cache-xsc3l2.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/arm/mm/cache-xsc3l2.c
+++ b/arch/arm/mm/cache-xsc3l2.c
@@ -97,7 +97,7 @@ static void xsc3_l2_inv_range(unsigned l
 	/*
 	 * Clean and invalidate partial last cache line.
 	 */
-	if (end & (CACHE_LINE_SIZE - 1)) {
+	if (start < end && (end & (CACHE_LINE_SIZE - 1))) {
 		xsc3_l2_clean_pa(end & ~(CACHE_LINE_SIZE - 1));
 		xsc3_l2_inv_pa(end & ~(CACHE_LINE_SIZE - 1));
 		end &= ~(CACHE_LINE_SIZE - 1);
@@ -106,7 +106,7 @@ static void xsc3_l2_inv_range(unsigned l
 	/*
 	 * Invalidate all full cache lines between 'start' and 'end'.
 	 */
-	while (start != end) {
+	while (start < end) {
 		xsc3_l2_inv_pa(start);
 		start += CACHE_LINE_SIZE;
 	}

--