[PATCH] xen: Introduce IS_ALIGNED()

[Andrew Cooper <andrew.cooper3@citrix.com>]

And a few open-coded alignment checks which I encountered

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Tim Deegan <tim@xen.org>
CC: Ian Campbell <Ian.Campbell@citrix.com>
---
 xen/arch/x86/mm.c          | 8 ++++----
 xen/arch/x86/xen.lds.S     | 2 +-
 xen/include/xen/config.h   | 2 ++
 xen/include/xen/tmem_xen.h | 3 +--
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index ea3f9f2..d6aaed8 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5957,8 +5957,8 @@ void destroy_xen_mappings(unsigned long s, unsigned long e)
     unsigned int  i;
     unsigned long v = s;
 
-    ASSERT((s & ~PAGE_MASK) == 0);
-    ASSERT((e & ~PAGE_MASK) == 0);
+    ASSERT(IS_ALIGNED(s, PAGE_SIZE));
+    ASSERT(IS_ALIGNED(e, PAGE_SIZE));
 
     while ( v < e )
     {
@@ -6369,8 +6369,8 @@ static void __memguard_change_range(void *p, unsigned long l, int guard)
     unsigned int flags = __PAGE_HYPERVISOR_RW | MAP_SMALL_PAGES;
 
     /* Ensure we are dealing with a page-aligned whole number of pages. */
-    ASSERT((_p&~PAGE_MASK) == 0);
-    ASSERT((_l&~PAGE_MASK) == 0);
+    ASSERT(IS_ALIGNED(_p, PAGE_SIZE));
+    ASSERT(IS_ALIGNED(_l, PAGE_SIZE));
 
     if ( guard )
         flags &= ~_PAGE_PRESENT;
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 3b199ca..9fde1db 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -229,4 +229,4 @@ ASSERT(__image_base__ > XEN_VIRT_START ||
 ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE, "kexec_reloc is too large")
 #endif
 
-ASSERT((cpu0_stack & (STACK_SIZE - 1)) == 0, "cpu0_stack misaligned")
+ASSERT(IS_ALIGNED(cpu0_stack, STACK_SIZE), "cpu0_stack misaligned")
diff --git a/xen/include/xen/config.h b/xen/include/xen/config.h
index a992933..bd78176 100644
--- a/xen/include/xen/config.h
+++ b/xen/include/xen/config.h
@@ -74,6 +74,8 @@
 #define MB(_mb)     (_AC(_mb, ULL) << 20)
 #define GB(_gb)     (_AC(_gb, ULL) << 30)
 
+#define IS_ALIGNED(val, align) (((val) & ((align) - 1)) == 0)
+
 #define __STR(...) #__VA_ARGS__
 #define STR(...) __STR(__VA_ARGS__)
 
diff --git a/xen/include/xen/tmem_xen.h b/xen/include/xen/tmem_xen.h
index 0fdbf68..c770f3e 100644
--- a/xen/include/xen/tmem_xen.h
+++ b/xen/include/xen/tmem_xen.h
@@ -23,8 +23,7 @@
 #endif
 typedef uint32_t pagesize_t;  /* like size_t, must handle largest PAGE_SIZE */
 
-#define IS_PAGE_ALIGNED(addr) \
-  ((void *)((((unsigned long)addr + (PAGE_SIZE - 1)) & PAGE_MASK)) == addr)
+#define IS_PAGE_ALIGNED(addr) IS_ALIGNED((unsigned long)(addr), PAGE_SIZE)
 #define IS_VALID_PAGE(_pi)  ( mfn_valid(page_to_mfn(_pi)) )
 
 extern struct page_list_head tmem_page_list;
-- 
2.1.4