1 files changed, 51 insertions, 15 deletions

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index ab517fcce21b..8fcda140358d 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -497,28 +497,64 @@ 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 flags)
+__do_cache_op(unsigned long start, unsigned long end)
 {
-        struct mm_struct *mm = current->active_mm;
-        struct vm_area_struct *vma;
+        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)
+{
         if (end < start || flags)
                 return -EINVAL;
 
-        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 (!access_ok(VERIFY_READ, start, end - start))
+                return -EFAULT;
 
-                up_read(&mm->mmap_sem);
-                return flush_cache_user_range(start, end);
-        }
-        up_read(&mm->mmap_sem);
-        return -EINVAL;
+        return __do_cache_op(start, end);
 }
 
 /*