[GIT,PULL] Cacheflush updates for 3.12

Commit Message

Jon Medhurst (Tixy) Dec. 5, 2013, 2:23 p.m. UTC

On Wed, 2013-12-04 at 16:13 +0000, Will Deacon wrote:
> took another look at that patch and can't see anything obviously wrong
> with it. 

If the memory region isn't guaranteed to be page aligned then doesn't it
flush up to PAGE_SIZE-1 more bytes than requested and so exceed the
bounds check in do_cache_op? Fixing this as below _appears_ to stop the
Browser crashes I'm seeing (still doing some more testing)...

Patch

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index dbf0923..cbc9dae 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -512,6 +512,10 @@  __do_cache_op(unsigned long start, unsigned long end)
        unsigned long chunk = PAGE_SIZE;
 
        do {
+               unsigned long chunk_end = start + chunk;
+               if (chunk_end > end)
+                       chunk_end = end;
+
                if (signal_pending(current)) {
                        struct thread_info *ti = current_thread_info();
 
@@ -531,7 +535,7 @@  __do_cache_op(unsigned long start, unsigned long end)
                        return -ERESTART_RESTARTBLOCK;
                }
 
-               ret = flush_cache_user_range(start, start + chunk);
+               ret = flush_cache_user_range(start, chunk_end);
                if (ret)
                        return ret;