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

Pull x86 mm changes from Peter Anvin:
 "This is a huge set of several partly interrelated (and concurrently
  developed) changes, which is why the branch history is messier than
  one would like.

  The *really* big items are two humonguous patchsets mostly developed
  by Yinghai Lu at my request, which completely revamps the way we
  create initial page tables.  In particular, rather than estimating how
  much memory we will need for page tables and then build them into that
  memory -- a calculation that has shown to be incredibly fragile -- we
  now build them (on 64 bits) with the aid of a "pseudo-linear mode" --
  a #PF handler which creates temporary page tables on demand.

  This has several advantages:

  1. It makes it much easier to support things that need access to data
     very early (a followon patchset uses this to load microcode way
     early in the kernel startup).

  2. It allows the kernel and all the kernel data objects to be invoked
     from above the 4 GB limit.  This allows kdump to work on very large
     systems.

  3. It greatly reduces the difference between Xen and native (Xen's
     equivalent of the #PF handler are the temporary page tables created
     by the domain builder), eliminating a bunch of fragile hooks.

  The patch series also gets us a bit closer to W^X.

  Additional work in this pull is the 64-bit get_user() work which you
  were also involved with, and a bunch of cleanups/speedups to
  __phys_addr()/__pa()."

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (105 commits)
  x86, mm: Move reserving low memory later in initialization
  x86, doc: Clarify the use of asm("%edx") in uaccess.h
  x86, mm: Redesign get_user with a __builtin_choose_expr hack
  x86: Be consistent with data size in getuser.S
  x86, mm: Use a bitfield to mask nuisance get_user() warnings
  x86/kvm: Fix compile warning in kvm_register_steal_time()
  x86-32: Add support for 64bit get_user()
  x86-32, mm: Remove reference to alloc_remap()
  x86-32, mm: Remove reference to resume_map_numa_kva()
  x86-32, mm: Rip out x86_32 NUMA remapping code
  x86/numa: Use __pa_nodebug() instead
  x86: Don't panic if can not alloc buffer for swiotlb
  mm: Add alloc_bootmem_low_pages_nopanic()
  x86, 64bit, mm: hibernate use generic mapping_init
  x86, 64bit, mm: Mark data/bss/brk to nx
  x86: Merge early kernel reserve for 32bit and 64bit
  x86: Add Crash kernel low reservation
  x86, kdump: Remove crashkernel range find limit for 64bit
  memblock: Add memblock_mem_size()
  x86, boot: Not need to check setup_header version for setup_data
  ...

1 files changed, 99 insertions, 32 deletions

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 849fc9e63c2f..57334f4cd3af 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -27,11 +27,81 @@
 #include <asm/bios_ebda.h>
 #include <asm/bootparam_utils.h>
 
-static void __init zap_identity_mappings(void)
+/*
+ * Manage page tables very early on.
+ */
+extern pgd_t early_level4_pgt[PTRS_PER_PGD];
+extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
+static unsigned int __initdata next_early_pgt = 2;
+
+/* Wipe all early page tables except for the kernel symbol map */
+static void __init reset_early_page_tables(void)
+{
+	unsigned long i;
+
+	for (i = 0; i < PTRS_PER_PGD-1; i++)
+		early_level4_pgt[i].pgd = 0;
+
+	next_early_pgt = 0;
+
+	write_cr3(__pa(early_level4_pgt));
+}
+
+/* Create a new PMD entry */
+int __init early_make_pgtable(unsigned long address)
 {
-	pgd_t *pgd = pgd_offset_k(0UL);
-	pgd_clear(pgd);
-	__flush_tlb_all();
+	unsigned long physaddr = address - __PAGE_OFFSET;
+	unsigned long i;
+	pgdval_t pgd, *pgd_p;
+	pudval_t pud, *pud_p;
+	pmdval_t pmd, *pmd_p;
+
+	/* Invalid address or early pgt is done ?  */
+	if (physaddr >= MAXMEM || read_cr3() != __pa(early_level4_pgt))
+		return -1;
+
+again:
+	pgd_p = &early_level4_pgt[pgd_index(address)].pgd;
+	pgd = *pgd_p;
+
+	/*
+	 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
+	 * critical -- __PAGE_OFFSET would point us back into the dynamic
+	 * range and we might end up looping forever...
+	 */
+	if (pgd)
+		pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
+	else {
+		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
+			reset_early_page_tables();
+			goto again;
+		}
+
+		pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
+		for (i = 0; i < PTRS_PER_PUD; i++)
+			pud_p[i] = 0;
+		*pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
+	}
+	pud_p += pud_index(address);
+	pud = *pud_p;
+
+	if (pud)
+		pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
+	else {
+		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
+			reset_early_page_tables();
+			goto again;
+		}
+
+		pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
+		for (i = 0; i < PTRS_PER_PMD; i++)
+			pmd_p[i] = 0;
+		*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
+	}
+	pmd = (physaddr & PMD_MASK) + (__PAGE_KERNEL_LARGE & ~_PAGE_GLOBAL);
+	pmd_p[pmd_index(address)] = pmd;
+
+	return 0;
 }
 
 /* Don't add a printk in there. printk relies on the PDA which is not initialized 
@@ -42,14 +112,25 @@ static void __init clear_bss(void)
 	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
 }
 
+static unsigned long get_cmd_line_ptr(void)
+{
+	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+
+	cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
+
+	return cmd_line_ptr;
+}
+
 static void __init copy_bootdata(char *real_mode_data)
 {
 	char * command_line;
+	unsigned long cmd_line_ptr;
 
 	memcpy(&boot_params, real_mode_data, sizeof boot_params);
 	sanitize_boot_params(&boot_params);
-	if (boot_params.hdr.cmd_line_ptr) {
-		command_line = __va(boot_params.hdr.cmd_line_ptr);
+	cmd_line_ptr = get_cmd_line_ptr();
+	if (cmd_line_ptr) {
+		command_line = __va(cmd_line_ptr);
 		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 	}
 }
@@ -72,14 +153,12 @@ void __init x86_64_start_kernel(char * real_mode_data)
 				(__START_KERNEL & PGDIR_MASK)));
 	BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
 
+	/* Kill off the identity-map trampoline */
+	reset_early_page_tables();
+
 	/* clear bss before set_intr_gate with early_idt_handler */
 	clear_bss();
 
-	/* Make NULL pointers segfault */
-	zap_identity_mappings();
-
-	max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT;
-
 	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
 #ifdef CONFIG_EARLY_PRINTK
 		set_intr_gate(i, &early_idt_handlers[i]);
@@ -89,37 +168,25 @@ void __init x86_64_start_kernel(char * real_mode_data)
 	}
 	load_idt((const struct desc_ptr *)&idt_descr);
 
+	copy_bootdata(__va(real_mode_data));
+
 	if (console_loglevel == 10)
 		early_printk("Kernel alive\n");
 
+	clear_page(init_level4_pgt);
+	/* set init_level4_pgt kernel high mapping*/
+	init_level4_pgt[511] = early_level4_pgt[511];
+
 	x86_64_start_reservations(real_mode_data);
 }
 
 void __init x86_64_start_reservations(char *real_mode_data)
 {
-	copy_bootdata(__va(real_mode_data));
-
-	memblock_reserve(__pa_symbol(&_text),
-			 __pa_symbol(&__bss_stop) - __pa_symbol(&_text));
-
-#ifdef CONFIG_BLK_DEV_INITRD
-	/* Reserve INITRD */
-	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
-		/* Assume only end is not page aligned */
-		unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
-		unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
-		unsigned long ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
-		memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
-	}
-#endif
+	/* version is always not zero if it is copied */
+	if (!boot_params.hdr.version)
+		copy_bootdata(__va(real_mode_data));
 
 	reserve_ebda_region();
 
-	/*
-	 * At this point everything still needed from the boot loader
-	 * or BIOS or kernel text should be early reserved or marked not
-	 * RAM in e820. All other memory is free game.
-	 */
-
 	start_kernel();
 }