ARM: cacheflush: don't bother rounding to nearest vma

do_cache_op finds the lowest VMA contained in the specified address
range and rounds the range to cover only the mapped addresses.

Since commit 4542b6a0fa6b ("ARM: 7365/1: drop unused parameter from
flush_cache_user_range") the VMA is not used for anything else in this
code and seeing as the low-level cache flushing routines return -EFAULT
if the address is not valid, there is no need for this range truncation.

This patch removes the VMA handling code from the cacheflushing syscall.

Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 2 insertions, 15 deletions

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 4d268d912b0e..9b2c5d42c143 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -550,24 +550,11 @@ static long do_cache_op_restart(struct restart_block *unused)
 static inline int
 do_cache_op(unsigned long start, unsigned long end, int flags)
 {
-        struct mm_struct *mm = current->active_mm;
-        struct vm_area_struct *vma;
-
         if (end < start || flags)
                 return -EINVAL;
 
-        down_read(&mm->mmap_sem);
-        vma = find_vma(mm, start);
-        if (!vma || vma->vm_start >= end) {
-                up_read(&mm->mmap_sem);
-                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);
+        if (!access_ok(VERIFY_READ, start, end - start))
+                return -EFAULT;
 
         return __do_cache_op(start, end);
 }