[tip:x86/fpu] x86/mpx: Restrict the mmap() size check to bounds tables

tip-bot for Dave Hansen
2015-06-09T12:33:33Z

Commit-ID: eb099e5bc5457c42043e57cf0f4ce574669b9697
Gitweb: http://git.kernel.org/tip/eb099e5bc5457c42043e57cf0f4ce574669b9697
Author: Dave Hansen <dave.hansen@linux.intel.com>
AuthorDate: Sun, 7 Jun 2015 11:37:02 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 9 Jun 2015 12:24:31 +0200

x86/mpx: Restrict the mmap() size check to bounds tables

The comment and code here are confusing. We do not currently
allocate the bounds directory in the kernel.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150607183702.222CEC2A@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/mm/mpx.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index 47e4a856..d6e02f3 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -46,8 +46,8 @@ static unsigned long mpx_mmap(unsigned long len)
vm_flags_t vm_flags;
struct vm_area_struct *vma;

- /* Only bounds table and bounds directory can be allocated here */
- if (len != MPX_BD_SIZE_BYTES && len != MPX_BT_SIZE_BYTES)
+ /* Only bounds table can be allocated here */
+ if (len != MPX_BT_SIZE_BYTES)
return -EINVAL;

down_write(&mm->mmap_sem);