From: Dave Hansen <dave.hansen@linux.intel.com>
Date: Sun, 7 Jun 2015 18:37:02 +0000 (-0700)
Subject: x86/mpx: Restrict the mmap() size check to bounds tables
X-Git-Tag: firefly_0821_release~176^2~1627^2~14
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=eb099e5bc5457c42043e57cf0f4ce574669b9697;p=firefly-linux-kernel-4.4.55.git

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>
---

diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index 47e4a8564012..d6e02f3adee0 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);