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

Pull x86 boot updates from Ingo Molnar:
 "The main changes:

   - add initial commits to randomize kernel memory section virtual
     addresses, enabled via a new kernel option: RANDOMIZE_MEMORY
     (Thomas Garnier, Kees Cook, Baoquan He, Yinghai Lu)

   - enhance KASLR (RANDOMIZE_BASE) physical memory randomization (Kees
     Cook)

   - EBDA/BIOS region boot quirk cleanups (Andy Lutomirski, Ingo Molnar)

   - misc cleanups/fixes"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Simplify EBDA-vs-BIOS reservation logic
  x86/boot: Clarify what x86_legacy_features.reserve_bios_regions does
  x86/boot: Reorganize and clean up the BIOS area reservation code
  x86/mm: Do not reference phys addr beyond kernel
  x86/mm: Add memory hotplug support for KASLR memory randomization
  x86/mm: Enable KASLR for vmalloc memory regions
  x86/mm: Enable KASLR for physical mapping memory regions
  x86/mm: Implement ASLR for kernel memory regions
  x86/mm: Separate variable for trampoline PGD
  x86/mm: Add PUD VA support for physical mapping
  x86/mm: Update physical mapping variable names
  x86/mm: Refactor KASLR entropy functions
  x86/KASLR: Fix boot crash with certain memory configurations
  x86/boot/64: Add forgotten end of function marker
  x86/KASLR: Allow randomization below the load address
  x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G
  x86/KASLR: Randomize virtual address separately
  x86/KASLR: Clarify identity map interface
  x86/boot: Refuse to build with data relocations
  x86/KASLR, x86/power: Remove x86 hibernation restrictions

1 files changed, 19 insertions, 10 deletions

diff --git a/arch/x86/boot/compressed/pagetable.c b/arch/x86/boot/compressed/pagetable.c
index 34b95df..56589d0 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);