[Xen-devel] [PATCH v11 9/9] xen: explicit casts when DECLARE_BOUNDS cannot be used

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Sometimes the static inline functions provided by DECLARE_BOUNDS cannot
be used. This patch uses explicit casts to uintptr_t in those cases.

M3CM: Rule-18.2: Subtraction between pointers shall only be applied to
pointers that address elements of the same array

https://wiki.sei.cmu.edu/confluence/display/c/ARR36-C.+Do+not+subtract+or+compare+two+pointers+that+do+not+refer+to+the+same+array

QAVerify: 2761
Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
CC: JBeulich@xxxxxxxx
CC: andrew.cooper3@xxxxxxxxxx
---
 xen/arch/x86/setup.c        | 3 ++-
 xen/common/virtual_region.c | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 2ac7f62..cb45b68 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -976,7 +976,8 @@ void __init noreturn __start_xen(unsigned long mbi_p)
          * respective reserve_e820_ram() invocation below.
          */
         mod[mbi->mods_count].mod_start = virt_to_mfn(_stext);
-        mod[mbi->mods_count].mod_end = __2M_rwdata_end - _stext;
+        mod[mbi->mods_count].mod_end = (uintptr_t)__2M_rwdata_end -
+                                       (uintptr_t) _stext;
     }
 
     modules_headroom = bzimage_headroom(bootstrap_map(mod), mod->mod_end);
diff --git a/xen/common/virtual_region.c b/xen/common/virtual_region.c
index aa23918..87ef33a 100644
--- a/xen/common/virtual_region.c
+++ b/xen/common/virtual_region.c
@@ -119,7 +119,9 @@ void __init setup_virtual_regions(const struct 
exception_table_entry *start,
         const struct bug_frame *s;
 
         s = bug_frames[i - 1];
-        sz = bug_frames[i] - s;
+        /* bug_frame[i] and s are pointers to different objects. */
+        sz = ((uintptr_t)bug_frames[i] - (uintptr_t)s) /
+             sizeof(struct bug_frame);
 
         core.frame[i - 1].n_bugs = sz;
         core.frame[i - 1].bugs = s;
-- 
1.9.1


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