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-rw-r--r--arch/powerpc/mm/mem.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 2dd6bdd31fe..22563b9664c 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -585,3 +585,21 @@ static int add_system_ram_resources(void)
return 0;
}
subsys_initcall(add_system_ram_resources);
+
+#ifdef CONFIG_STRICT_DEVMEM
+/*
+ * devmem_is_allowed(): check to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ * Access has to be given to non-kernel-ram areas as well, these contain the
+ * PCI mmio resources as well as potential bios/acpi data regions.
+ */
+int devmem_is_allowed(unsigned long pfn)
+{
+ if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+ return 0;
+ if (!page_is_ram(pfn))
+ return 1;
+ return 0;
+}
+#endif /* CONFIG_STRICT_DEVMEM */