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Diffstat (limited to 'arch/x86/boot/compressed/pagetable.c')
-rw-r--r--arch/x86/boot/compressed/pagetable.c29
1 files changed, 19 insertions, 10 deletions
diff --git a/arch/x86/boot/compressed/pagetable.c b/arch/x86/boot/compressed/pagetable.c
index 34b95df14e69..56589d0a804b 100644
--- a/arch/x86/boot/compressed/pagetable.c
+++ b/arch/x86/boot/compressed/pagetable.c
@@ -2,6 +2,9 @@
* This code is used on x86_64 to create page table identity mappings on
* demand by building up a new set of page tables (or appending to the
* existing ones), and then switching over to them when ready.
+ *
+ * Copyright (C) 2015-2016 Yinghai Lu
+ * Copyright (C) 2016 Kees Cook
*/
/*
@@ -17,6 +20,9 @@
/* These actually do the work of building the kernel identity maps. */
#include <asm/init.h>
#include <asm/pgtable.h>
+/* Use the static base for this part of the boot process */
+#undef __PAGE_OFFSET
+#define __PAGE_OFFSET __PAGE_OFFSET_BASE
#include "../../mm/ident_map.c"
/* Used by pgtable.h asm code to force instruction serialization. */
@@ -59,9 +65,21 @@ static struct alloc_pgt_data pgt_data;
/* The top level page table entry pointer. */
static unsigned long level4p;
+/*
+ * Mapping information structure passed to kernel_ident_mapping_init().
+ * Due to relocation, pointers must be assigned at run time not build time.
+ */
+static struct x86_mapping_info mapping_info = {
+ .pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
+};
+
/* Locates and clears a region for a new top level page table. */
-static void prepare_level4(void)
+void initialize_identity_maps(void)
{
+ /* Init mapping_info with run-time function/buffer pointers. */
+ mapping_info.alloc_pgt_page = alloc_pgt_page;
+ mapping_info.context = &pgt_data;
+
/*
* It should be impossible for this not to already be true,
* but since calling this a second time would rewind the other
@@ -96,17 +114,8 @@ static void prepare_level4(void)
*/
void add_identity_map(unsigned long start, unsigned long size)
{
- struct x86_mapping_info mapping_info = {
- .alloc_pgt_page = alloc_pgt_page,
- .context = &pgt_data,
- .pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
- };
unsigned long end = start + size;
- /* Make sure we have a top level page table ready to use. */
- if (!level4p)
- prepare_level4();
-
/* Align boundary to 2M. */
start = round_down(start, PMD_SIZE);
end = round_up(end, PMD_SIZE);