Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux...

[sfrench/cifs-2.6.git] / arch / x86 / mm / init_64.c

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 1ff7906a9a4dbc7afa6dfdd24f274e077cd26773..0cca626630377738a8af7d8f16a29dfdad5ac27e 100644 (file)
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -135,7 +135,7 @@ static __init void *spp_getpage(void)
        return ptr;
 }
 
-static __init void
+static void
 set_pte_phys(unsigned long vaddr, unsigned long phys, pgprot_t prot)
 {
        pgd_t *pgd;
@@ -173,7 +173,7 @@ set_pte_phys(unsigned long vaddr, unsigned long phys, pgprot_t prot)
        new_pte = pfn_pte(phys >> PAGE_SHIFT, prot);
 
        pte = pte_offset_kernel(pmd, vaddr);
-       if (!pte_none(*pte) &&
+       if (!pte_none(*pte) && pte_val(new_pte) &&
            pte_val(*pte) != (pte_val(new_pte) & __supported_pte_mask))
                pte_ERROR(*pte);
        set_pte(pte, new_pte);
@@ -214,8 +214,7 @@ void __init cleanup_highmap(void)
 }
 
 /* NOTE: this is meant to be run only at boot */
-void __init
-__set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
+void __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
 {
        unsigned long address = __fix_to_virt(idx);
 
@@ -664,6 +663,26 @@ EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ *
+ * On x86, access has to be given to the first megabyte of ram because that area
+ * contains bios code and data regions used by X and dosemu and similar apps.
+ * 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 pagenr)
+{
+       if (pagenr <= 256)
+               return 1;
+       if (!page_is_ram(pagenr))
+               return 1;
+       return 0;
+}
+
+
 static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel,
                         kcore_modules, kcore_vsyscall;