From: Julien Grall <julien.grall@arm.com>
Date: Wed, 3 Apr 2019 10:14:10 +0000 (+0100)
Subject: xen/arm: mm: Check start is always before end in {destroy, modify}_xen_mappings
X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~2091
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=7e80a539e2805cb63c432caf7d0acafdfa1802d5;p=xen.git

xen/arm: mm: Check start is always before end in {destroy, modify}_xen_mappings

The two helpers {destroy, modify}_xen_mappings don't check that the
start is always before the end. This should never happen but if it
happens, it will result to unexpected behavior.

Catch such issues earlier on by adding an ASSERT in destroy_xen_mappings
and modify_xen_mappings.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 2ad12da5d1..6a549e9283 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1039,11 +1039,13 @@ int populate_pt_range(unsigned long virt, unsigned long nr_mfns)
 
 int destroy_xen_mappings(unsigned long v, unsigned long e)
 {
+    ASSERT(v <= e);
     return create_xen_entries(REMOVE, v, INVALID_MFN, (e - v) >> PAGE_SHIFT, 0);
 }
 
 int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int flags)
 {
+    ASSERT(s <= e);
     return create_xen_entries(MODIFY, s, INVALID_MFN, (e - s) >> PAGE_SHIFT,
                               flags);
 }