ARM: 7917/1: cacheflush: correctly limit range of memory region being flushed

The __do_cache_op function operates with a 'chunk' size of one page
but fails to limit the size of the final chunk so as to not exceed
the specified memory region. Fix this.

Cc: <stable@vger.kernel.org>
Reported-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Tested-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index dbf0923e8d76..7940241f0576 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -509,9 +509,10 @@ static inline int
 __do_cache_op(unsigned long start, unsigned long end)
 {
         int ret;
-        unsigned long chunk = PAGE_SIZE;
 
         do {
+                unsigned long chunk = min(PAGE_SIZE, end - start);
+
                 if (signal_pending(current)) {
                         struct thread_info *ti = current_thread_info();