[XEN PATCH v3] arm/mem_access: add conditional build of mem_access.c

[Alessandro Zucchelli <alessandro.zucchelli@xxxxxxxxxxx>]

In order to comply to MISRA C:2012 Rule 8.4 for ARM the following
changes are done:
revert preprocessor conditional changes to xen/mem_access.h which
had it build unconditionally, add conditional build for xen/mem_access.c
as well and provide stubs in asm/mem_access.h for the users of this
header.

Signed-off-by: Alessandro Zucchelli <alessandro.zucchelli@xxxxxxxxxxx>
---
Changes from v2:
Stylistic changes to code aimed to respect xen's coding guidelines.
---
Changes from v1:
Reverted preprocessor conditional changes to xen/mem_access.h;
added conditional build for xen/mem_access.c;
provided stubs for asm/mem_access.h functions
---
 xen/arch/arm/Makefile                 |  2 +-
 xen/arch/arm/include/asm/mem_access.h | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 7b1350e2ef..45dc29ea53 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -37,7 +37,7 @@ obj-$(CONFIG_IOREQ_SERVER) += ioreq.o
 obj-y += irq.o
 obj-y += kernel.init.o
 obj-$(CONFIG_LIVEPATCH) += livepatch.o
-obj-y += mem_access.o
+obj-$(CONFIG_MEM_ACCESS) += mem_access.o
 obj-y += mm.o
 obj-y += monitor.o
 obj-y += p2m.o
diff --git a/xen/arch/arm/include/asm/mem_access.h 
b/xen/arch/arm/include/asm/mem_access.h
index 35ed0ad154..abac8032fc 100644
--- a/xen/arch/arm/include/asm/mem_access.h
+++ b/xen/arch/arm/include/asm/mem_access.h
@@ -17,6 +17,8 @@
 #ifndef _ASM_ARM_MEM_ACCESS_H
 #define _ASM_ARM_MEM_ACCESS_H
 
+#include <xen/types.h>
+
 static inline
 bool p2m_mem_access_emulate_check(struct vcpu *v,
                                   const struct vm_event_st *rsp)
@@ -35,12 +37,28 @@ static inline bool p2m_mem_access_sanity_check(struct 
domain *d)
  * Send mem event based on the access. Boolean return value indicates if trap
  * needs to be injected into guest.
  */
+#ifdef CONFIG_MEM_ACCESS
 bool p2m_mem_access_check(paddr_t gpa, vaddr_t gla, const struct npfec npfec);
 
 struct page_info*
 p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned long flag,
                                   const struct vcpu *v);
+#else
+
+static inline bool
+p2m_mem_access_check(paddr_t gpa, vaddr_t gla, const struct npfec npfec)
+{
+    return false;
+}
+
+static inline struct page_info*
+p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned long flag,
+                                  const struct vcpu *v)
+{
+    return NULL;
+}
 
+#endif /*CONFIG_MEM_ACCESS*/
 #endif /* _ASM_ARM_MEM_ACCESS_H */
 
 /*
-- 
2.25.1