2 files changed, 68 insertions, 8 deletions

diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 214d4158089a..7d77645128a8 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -43,6 +43,16 @@ struct cpu_context_save {
 	__u32	extra[2];		/* Xscale 'acc' register, etc */
 };
 
+struct arm_restart_block {
+	union {
+		/* For user cache flushing */
+		struct {
+			unsigned long start;
+			unsigned long end;
+		} cache;
+	};
+};
+
 /*
  * low level task data that entry.S needs immediate access to.
  * __switch_to() assumes cpu_context follows immediately after cpu_domain.
@@ -68,6 +78,7 @@ struct thread_info {
 	unsigned long		thumbee_state;	/* ThumbEE Handler Base register */
 #endif
 	struct restart_block	restart_block;
+	struct arm_restart_block	arm_restart_block;
 };
 
 #define INIT_THREAD_INFO(tsk)						\
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index cab094c234ee..4d268d912b0e 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -499,6 +499,54 @@ static int bad_syscall(int n, struct pt_regs *regs)
 	return regs->ARM_r0;
 }
 
+static long do_cache_op_restart(struct restart_block *);
+
+static inline int
+__do_cache_op(unsigned long start, unsigned long end)
+{
+	int ret;
+	unsigned long chunk = PAGE_SIZE;
+
+	do {
+		if (signal_pending(current)) {
+			struct thread_info *ti = current_thread_info();
+
+			ti->restart_block = (struct restart_block) {
+				.fn	= do_cache_op_restart,
+			};
+
+			ti->arm_restart_block = (struct arm_restart_block) {
+				{
+					.cache = {
+						.start	= start,
+						.end	= end,
+					},
+				},
+			};
+
+			return -ERESTART_RESTARTBLOCK;
+		}
+
+		ret = flush_cache_user_range(start, start + chunk);
+		if (ret)
+			return ret;
+
+		cond_resched();
+		start += chunk;
+	} while (start < end);
+
+	return 0;
+}
+
+static long do_cache_op_restart(struct restart_block *unused)
+{
+	struct arm_restart_block *restart_block;
+
+	restart_block = &current_thread_info()->arm_restart_block;
+	return __do_cache_op(restart_block->cache.start,
+			     restart_block->cache.end);
+}
+
 static inline int
 do_cache_op(unsigned long start, unsigned long end, int flags)
 {
@@ -510,17 +558,18 @@ do_cache_op(unsigned long start, unsigned long end, int flags)
 
 	down_read(&mm->mmap_sem);
 	vma = find_vma(mm, start);
-	if (vma && vma->vm_start < end) {
-		if (start < vma->vm_start)
-			start = vma->vm_start;
-		if (end > vma->vm_end)
-			end = vma->vm_end;
-
+	if (!vma || vma->vm_start >= end) {
 		up_read(&mm->mmap_sem);
-		return flush_cache_user_range(start, end);
+		return -EINVAL;
 	}
+
+	if (start < vma->vm_start)
+		start = vma->vm_start;
+	if (end > vma->vm_end)
+		end = vma->vm_end;
 	up_read(&mm->mmap_sem);
-	return -EINVAL;
+
+	return __do_cache_op(start, end);
 }
 
 /*