[S390] mm: add devmem_is_allowed() for STRICT_DEVMEM checking
Provide the devmem_is_allowed() routine to restrict access to
kernel memory from userspace.
Set the CONFIG_STRICT_DEVMEM config option to switch on checking.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index a8729ea..3c987e9 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -130,6 +130,11 @@
void arch_free_page(struct page *page, int order);
void arch_alloc_page(struct page *page, int order);
+static inline int devmem_is_allowed(unsigned long pfn)
+{
+ return 0;
+}
+
#define HAVE_ARCH_FREE_PAGE
#define HAVE_ARCH_ALLOC_PAGE