arm64: compat: align cacheflush syscall with arch/arm

Update handling of cacheflush syscall with changes made in arch/arm
counterpart:
 - return error to userspace when flushing syscall fails
 - split user cache-flushing into interruptible chunks
 - don't bother rounding to nearest vma

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
[will: changed internal return value from -EINTR to 0 to match arch/arm/]
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 8eaf18577d71..2560e1e1562e 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -17,6 +17,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/errno.h>
 #include <linux/linkage.h>
 #include <linux/init.h>
 #include <asm/assembler.h>
@@ -140,9 +141,12 @@ USER(9f, ic	ivau, x4	)		// invalidate I line PoU
         add     x4, x4, x2
         cmp     x4, x1
         b.lo    1b
-9:                                              // ignore any faulting cache operation
         dsb     ish
         isb
+        mov     x0, #0
+        ret
+9:
+        mov     x0, #-EFAULT
         ret
 ENDPROC(flush_icache_range)
 ENDPROC(__flush_cache_user_range)