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, 127 insertions, 83 deletions

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 980053c..d94f6d6 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -47,14 +47,13 @@ L3_START_KERNEL = pud_index(__START_KERNEL_map)
 	.code64
 	.globl startup_64
 startup_64:
-
 	/*
 	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
 	 * and someone has loaded an identity mapped page table
 	 * for us.  These identity mapped page tables map all of the
 	 * kernel pages and possibly all of memory.
 	 *
-	 * %esi holds a physical pointer to real_mode_data.
+	 * %rsi holds a physical pointer to real_mode_data.
 	 *
 	 * We come here either directly from a 64bit bootloader, or from
 	 * arch/x86_64/boot/compressed/head.S.
@@ -66,7 +65,8 @@ startup_64:
 	 * tables and then reload them.
 	 */
 
-	/* Compute the delta between the address I am compiled to run at and the
+	/*
+	 * Compute the delta between the address I am compiled to run at and the
 	 * address I am actually running at.
 	 */
 	leaq	_text(%rip), %rbp
@@ -78,45 +78,62 @@ startup_64:
 	testl	%eax, %eax
 	jnz	bad_address
 
-	/* Is the address too large? */
-	leaq	_text(%rip), %rdx
-	movq	$PGDIR_SIZE, %rax
-	cmpq	%rax, %rdx
-	jae	bad_address
-
-	/* Fixup the physical addresses in the page table
+	/*
+	 * Is the address too large?
 	 */
-	addq	%rbp, init_level4_pgt + 0(%rip)
-	addq	%rbp, init_level4_pgt + (L4_PAGE_OFFSET*8)(%rip)
-	addq	%rbp, init_level4_pgt + (L4_START_KERNEL*8)(%rip)
+	leaq	_text(%rip), %rax
+	shrq	$MAX_PHYSMEM_BITS, %rax
+	jnz	bad_address
 
-	addq	%rbp, level3_ident_pgt + 0(%rip)
+	/*
+	 * Fixup the physical addresses in the page table
+	 */
+	addq	%rbp, early_level4_pgt + (L4_START_KERNEL*8)(%rip)
 
 	addq	%rbp, level3_kernel_pgt + (510*8)(%rip)
 	addq	%rbp, level3_kernel_pgt + (511*8)(%rip)
 
 	addq	%rbp, level2_fixmap_pgt + (506*8)(%rip)
 
-	/* Add an Identity mapping if I am above 1G */
+	/*
+	 * Set up the identity mapping for the switchover.  These
+	 * entries should *NOT* have the global bit set!  This also
+	 * creates a bunch of nonsense entries but that is fine --
+	 * it avoids problems around wraparound.
+	 */
 	leaq	_text(%rip), %rdi
-	andq	$PMD_PAGE_MASK, %rdi
+	leaq	early_level4_pgt(%rip), %rbx
 
 	movq	%rdi, %rax
-	shrq	$PUD_SHIFT, %rax
-	andq	$(PTRS_PER_PUD - 1), %rax
-	jz	ident_complete
+	shrq	$PGDIR_SHIFT, %rax
 
-	leaq	(level2_spare_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
-	leaq	level3_ident_pgt(%rip), %rbx
-	movq	%rdx, 0(%rbx, %rax, 8)
+	leaq	(4096 + _KERNPG_TABLE)(%rbx), %rdx
+	movq	%rdx, 0(%rbx,%rax,8)
+	movq	%rdx, 8(%rbx,%rax,8)
 
+	addq	$4096, %rdx
 	movq	%rdi, %rax
-	shrq	$PMD_SHIFT, %rax
-	andq	$(PTRS_PER_PMD - 1), %rax
-	leaq	__PAGE_KERNEL_IDENT_LARGE_EXEC(%rdi), %rdx
-	leaq	level2_spare_pgt(%rip), %rbx
-	movq	%rdx, 0(%rbx, %rax, 8)
-ident_complete:
+	shrq	$PUD_SHIFT, %rax
+	andl	$(PTRS_PER_PUD-1), %eax
+	movq	%rdx, (4096+0)(%rbx,%rax,8)
+	movq	%rdx, (4096+8)(%rbx,%rax,8)
+
+	addq	$8192, %rbx
+	movq	%rdi, %rax
+	shrq	$PMD_SHIFT, %rdi
+	addq	$(__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL), %rax
+	leaq	(_end - 1)(%rip), %rcx
+	shrq	$PMD_SHIFT, %rcx
+	subq	%rdi, %rcx
+	incl	%ecx
+
+1:
+	andq	$(PTRS_PER_PMD - 1), %rdi
+	movq	%rax, (%rbx,%rdi,8)
+	incq	%rdi
+	addq	$PMD_SIZE, %rax
+	decl	%ecx
+	jnz	1b
 
 	/*
 	 * Fixup the kernel text+data virtual addresses. Note that
@@ -124,7 +141,6 @@ ident_complete:
 	 * cleanup_highmap() fixes this up along with the mappings
 	 * beyond _end.
 	 */
-
 	leaq	level2_kernel_pgt(%rip), %rdi
 	leaq	4096(%rdi), %r8
 	/* See if it is a valid page table entry */
@@ -139,17 +155,14 @@ ident_complete:
 	/* Fixup phys_base */
 	addq	%rbp, phys_base(%rip)
 
-	/* Due to ENTRY(), sometimes the empty space gets filled with
-	 * zeros. Better take a jmp than relying on empty space being
-	 * filled with 0x90 (nop)
-	 */
-	jmp secondary_startup_64
+	movq	$(early_level4_pgt - __START_KERNEL_map), %rax
+	jmp 1f
 ENTRY(secondary_startup_64)
 	/*
 	 * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
 	 * and someone has loaded a mapped page table.
 	 *
-	 * %esi holds a physical pointer to real_mode_data.
+	 * %rsi holds a physical pointer to real_mode_data.
 	 *
 	 * We come here either from startup_64 (using physical addresses)
 	 * or from trampoline.S (using virtual addresses).
@@ -159,12 +172,14 @@ ENTRY(secondary_startup_64)
 	 * after the boot processor executes this code.
 	 */
 
+	movq	$(init_level4_pgt - __START_KERNEL_map), %rax
+1:
+
 	/* Enable PAE mode and PGE */
-	movl	$(X86_CR4_PAE | X86_CR4_PGE), %eax
-	movq	%rax, %cr4
+	movl	$(X86_CR4_PAE | X86_CR4_PGE), %ecx
+	movq	%rcx, %cr4
 
 	/* Setup early boot stage 4 level pagetables. */
-	movq	$(init_level4_pgt - __START_KERNEL_map), %rax
 	addq	phys_base(%rip), %rax
 	movq	%rax, %cr3
 
@@ -196,7 +211,7 @@ ENTRY(secondary_startup_64)
 	movq	%rax, %cr0
 
 	/* Setup a boot time stack */
-	movq stack_start(%rip),%rsp
+	movq stack_start(%rip), %rsp
 
 	/* zero EFLAGS after setting rsp */
 	pushq $0
@@ -236,15 +251,33 @@ ENTRY(secondary_startup_64)
 	movl	initial_gs+4(%rip),%edx
 	wrmsr	
 
-	/* esi is pointer to real mode structure with interesting info.
+	/* rsi is pointer to real mode structure with interesting info.
 	   pass it to C */
-	movl	%esi, %edi
+	movq	%rsi, %rdi
 	
 	/* Finally jump to run C code and to be on real kernel address
 	 * Since we are running on identity-mapped space we have to jump
 	 * to the full 64bit address, this is only possible as indirect
 	 * jump.  In addition we need to ensure %cs is set so we make this
 	 * a far return.
+	 *
+	 * Note: do not change to far jump indirect with 64bit offset.
+	 *
+	 * AMD does not support far jump indirect with 64bit offset.
+	 * AMD64 Architecture Programmer's Manual, Volume 3: states only
+	 *	JMP FAR mem16:16 FF /5 Far jump indirect,
+	 *		with the target specified by a far pointer in memory.
+	 *	JMP FAR mem16:32 FF /5 Far jump indirect,
+	 *		with the target specified by a far pointer in memory.
+	 *
+	 * Intel64 does support 64bit offset.
+	 * Software Developer Manual Vol 2: states:
+	 *	FF /5 JMP m16:16 Jump far, absolute indirect,
+	 *		address given in m16:16
+	 *	FF /5 JMP m16:32 Jump far, absolute indirect,
+	 *		address given in m16:32.
+	 *	REX.W + FF /5 JMP m16:64 Jump far, absolute indirect,
+	 *		address given in m16:64.
 	 */
 	movq	initial_code(%rip),%rax
 	pushq	$0		# fake return address to stop unwinder
@@ -270,13 +303,13 @@ ENDPROC(start_cpu0)
 
 	/* SMP bootup changes these two */
 	__REFDATA
-	.align	8
-	ENTRY(initial_code)
+	.balign	8
+	GLOBAL(initial_code)
 	.quad	x86_64_start_kernel
-	ENTRY(initial_gs)
+	GLOBAL(initial_gs)
 	.quad	INIT_PER_CPU_VAR(irq_stack_union)
 
-	ENTRY(stack_start)
+	GLOBAL(stack_start)
 	.quad  init_thread_union+THREAD_SIZE-8
 	.word  0
 	__FINITDATA
@@ -284,7 +317,7 @@ ENDPROC(start_cpu0)
 bad_address:
 	jmp bad_address
 
-	.section ".init.text","ax"
+	__INIT
 	.globl early_idt_handlers
 early_idt_handlers:
 	# 104(%rsp) %rflags
@@ -321,14 +354,22 @@ ENTRY(early_idt_handler)
 	pushq %r11		#  0(%rsp)
 
 	cmpl $__KERNEL_CS,96(%rsp)
-	jne 10f
+	jne 11f
+
+	cmpl $14,72(%rsp)	# Page fault?
+	jnz 10f
+	GET_CR2_INTO(%rdi)	# can clobber any volatile register if pv
+	call early_make_pgtable
+	andl %eax,%eax
+	jz 20f			# All good
 
+10:
 	leaq 88(%rsp),%rdi	# Pointer to %rip
 	call early_fixup_exception
 	andl %eax,%eax
 	jnz 20f			# Found an exception entry
 
-10:
+11:
 #ifdef CONFIG_EARLY_PRINTK
 	GET_CR2_INTO(%r9)	# can clobber any volatile register if pv
 	movl 80(%rsp),%r8d	# error code
@@ -350,7 +391,7 @@ ENTRY(early_idt_handler)
 1:	hlt
 	jmp 1b
 
-20:	# Exception table entry found
+20:	# Exception table entry found or page table generated
 	popq %r11
 	popq %r10
 	popq %r9
@@ -364,6 +405,8 @@ ENTRY(early_idt_handler)
 	decl early_recursion_flag(%rip)
 	INTERRUPT_RETURN
 
+	__INITDATA
+
 	.balign 4
 early_recursion_flag:
 	.long 0
@@ -374,11 +417,10 @@ early_idt_msg:
 early_idt_ripmsg:
 	.asciz "RIP %s\n"
 #endif /* CONFIG_EARLY_PRINTK */
-	.previous
 
 #define NEXT_PAGE(name) \
 	.balign	PAGE_SIZE; \
-ENTRY(name)
+GLOBAL(name)
 
 /* Automate the creation of 1 to 1 mapping pmd entries */
 #define PMDS(START, PERM, COUNT)			\
@@ -388,24 +430,37 @@ ENTRY(name)
 	i = i + 1 ;					\
 	.endr
 
+	__INITDATA
+NEXT_PAGE(early_level4_pgt)
+	.fill	511,8,0
+	.quad	level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
+
+NEXT_PAGE(early_dynamic_pgts)
+	.fill	512*EARLY_DYNAMIC_PAGE_TABLES,8,0
+
 	.data
-	/*
-	 * This default setting generates an ident mapping at address 0x100000
-	 * and a mapping for the kernel that precisely maps virtual address
-	 * 0xffffffff80000000 to physical address 0x000000. (always using
-	 * 2Mbyte large pages provided by PAE mode)
-	 */
+
+#ifndef CONFIG_XEN
 NEXT_PAGE(init_level4_pgt)
-	.quad	level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
-	.org	init_level4_pgt + L4_PAGE_OFFSET*8, 0
-	.quad	level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
-	.org	init_level4_pgt + L4_START_KERNEL*8, 0
+	.fill	512,8,0
+#else
+NEXT_PAGE(init_level4_pgt)
+	.quad   level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+	.org    init_level4_pgt + L4_PAGE_OFFSET*8, 0
+	.quad   level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+	.org    init_level4_pgt + L4_START_KERNEL*8, 0
 	/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
-	.quad	level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
+	.quad   level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
 
 NEXT_PAGE(level3_ident_pgt)
 	.quad	level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
-	.fill	511,8,0
+	.fill	511, 8, 0
+NEXT_PAGE(level2_ident_pgt)
+	/* Since I easily can, map the first 1G.
+	 * Don't set NX because code runs from these pages.
+	 */
+	PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
+#endif
 
 NEXT_PAGE(level3_kernel_pgt)
 	.fill	L3_START_KERNEL,8,0
@@ -413,21 +468,6 @@ NEXT_PAGE(level3_kernel_pgt)
 	.quad	level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
 	.quad	level2_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE
 
-NEXT_PAGE(level2_fixmap_pgt)
-	.fill	506,8,0
-	.quad	level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE
-	/* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */
-	.fill	5,8,0
-
-NEXT_PAGE(level1_fixmap_pgt)
-	.fill	512,8,0
-
-NEXT_PAGE(level2_ident_pgt)
-	/* Since I easily can, map the first 1G.
-	 * Don't set NX because code runs from these pages.
-	 */
-	PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
-
 NEXT_PAGE(level2_kernel_pgt)
 	/*
 	 * 512 MB kernel mapping. We spend a full page on this pagetable
@@ -442,11 +482,16 @@ NEXT_PAGE(level2_kernel_pgt)
 	PMDS(0, __PAGE_KERNEL_LARGE_EXEC,
 		KERNEL_IMAGE_SIZE/PMD_SIZE)
 
-NEXT_PAGE(level2_spare_pgt)
-	.fill   512, 8, 0
+NEXT_PAGE(level2_fixmap_pgt)
+	.fill	506,8,0
+	.quad	level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE
+	/* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */
+	.fill	5,8,0
+
+NEXT_PAGE(level1_fixmap_pgt)
+	.fill	512,8,0
 
 #undef PMDS
-#undef NEXT_PAGE
 
 	.data
 	.align 16
@@ -472,6 +517,5 @@ ENTRY(nmi_idt_table)
 	.skip IDT_ENTRIES * 16
 
 	__PAGE_ALIGNED_BSS
-	.align PAGE_SIZE
-ENTRY(empty_zero_page)
+NEXT_PAGE(empty_zero_page)
 	.skip PAGE_SIZE