text: /*
   *  Copyright (C) 1995  Linus Torvalds
   *
   *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
   *
   *  Memory region support
   *	David Parsons <orc@pell.chi.il.us>, July-August 1999
   *
   *  Added E820 sanitization routine (removes overlapping memory regions);
   *  Brian Moyle <bmoyle@mvista.com>, February 2001
   *
   * Moved CPU detection code to cpu/${cpu}.c
   *    Patrick Mochel <mochel@osdl.org>, March 2002
   *
   *  Provisions for empty E820 memory regions (reported by certain BIOSes).
   *  Alex Achenbach <xela@slit.de>, December 2002.
   *
   */
  
  /*
   * This file handles the architecture-dependent parts of initialization
   */
  
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/mmzone.h>
  #include <linux/screen_info.h>
  #include <linux/ioport.h>
  #include <linux/acpi.h>
  #include <linux/sfi.h>
  #include <linux/apm_bios.h>
  #include <linux/initrd.h>
  #include <linux/memblock.h>
  #include <linux/seq_file.h>
  #include <linux/console.h>
  #include <linux/root_dev.h>
  #include <linux/highmem.h>
  #include <linux/export.h>
  #include <linux/efi.h>
  #include <linux/init.h>
  #include <linux/edd.h>
  #include <linux/iscsi_ibft.h>
  #include <linux/nodemask.h>
  #include <linux/kexec.h>
  #include <linux/dmi.h>
  #include <linux/pfn.h>
  #include <linux/pci.h>
  #include <asm/pci-direct.h>
  #include <linux/init_ohci1394_dma.h>
  #include <linux/kvm_para.h>
  #include <linux/dma-contiguous.h>
  #include <xen/xen.h>
  
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/stddef.h>
  #include <linux/unistd.h>
  #include <linux/ptrace.h>
  #include <linux/user.h>
  #include <linux/delay.h>
  
  #include <linux/kallsyms.h>
  #include <linux/cpufreq.h>
  #include <linux/dma-mapping.h>
  #include <linux/ctype.h>
  #include <linux/uaccess.h>
  
  #include <linux/percpu.h>
  #include <linux/crash_dump.h>
  #include <linux/tboot.h>
  #include <linux/jiffies.h>
  #include <linux/mem_encrypt.h>
  
  #include <linux/usb/xhci-dbgp.h>
  #include <video/edid.h>
  
  #include <asm/mtrr.h>
  #include <asm/apic.h>
  #include <asm/realmode.h>
  #include <asm/e820/api.h>
  #include <asm/mpspec.h>
  #include <asm/setup.h>
  #include <asm/efi.h>
  #include <asm/timer.h>
  #include <asm/i8259.h>
  #include <asm/sections.h>
  #include <asm/io_apic.h>
  #include <asm/ist.h>
  #include <asm/setup_arch.h>
  #include <asm/bios_ebda.h>
  #include <asm/cacheflush.h>
  #include <asm/processor.h>
  #include <asm/bugs.h>
  #include <asm/kasan.h>
  
  #include <asm/vsyscall.h>
  #include <asm/cpu.h>
  #include <asm/desc.h>
  #include <asm/dma.h>
  #include <asm/iommu.h>
  #include <asm/gart.h>
  #include <asm/mmu_context.h>
  #include <asm/proto.h>
  
  #include <asm/paravirt.h>
  #include <asm/hypervisor.h>
  #include <asm/olpc_ofw.h>
  
  #include <asm/percpu.h>
  #include <asm/topology.h>
  #include <asm/apicdef.h>
  #include <asm/amd_nb.h>
  #include <asm/mce.h>
  #include <asm/alternative.h>
  #include <asm/prom.h>
  #include <asm/microcode.h>
  #include <asm/kaslr.h>
  #include <asm/unwind.h>
  
  /*
   * max_low_pfn_mapped: highest direct mapped pfn under 4GB
   * max_pfn_mapped:     highest direct mapped pfn over 4GB
   *
   * The direct mapping only covers E820_TYPE_RAM regions, so the ranges and gaps are
   * represented by pfn_mapped
   */
  unsigned long max_low_pfn_mapped;
  unsigned long max_pfn_mapped;
  
  #ifdef CONFIG_DMI
  RESERVE_BRK(dmi_alloc, 65536);
  #endif
  
  
  static __initdata unsigned long _brk_start = (unsigned long)__brk_base;
  unsigned long _brk_end = (unsigned long)__brk_base;
  
  struct boot_params boot_params;
  
  /*
   * Machine setup..
   */
  static struct resource data_resource = {
  	.name	= "Kernel data",
  	.start	= 0,
  	.end	= 0,
  	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
  };
  
  static struct resource code_resource = {
  	.name	= "Kernel code",
  	.start	= 0,
  	.end	= 0,
  	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
  };
  
  static struct resource bss_resource = {
  	.name	= "Kernel bss",
  	.start	= 0,
  	.end	= 0,
  	.flags	= IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
  };
  
  
  #ifdef CONFIG_X86_32
  /* cpu data as detected by the assembly code in head_32.S */
  struct cpuinfo_x86 new_cpu_data;
  
  /* common cpu data for all cpus */
  struct cpuinfo_x86 boot_cpu_data __read_mostly;
  EXPORT_SYMBOL(boot_cpu_data);
  
  unsigned int def_to_bigsmp;
  
  /* for MCA, but anyone else can use it if they want */
  unsigned int machine_id;
  unsigned int machine_submodel_id;
  unsigned int BIOS_revision;
  
  struct apm_info apm_info;
  EXPORT_SYMBOL(apm_info);
  
  #if defined(CONFIG_X86_SPEEDSTEP_SMI) || \
  	defined(CONFIG_X86_SPEEDSTEP_SMI_MODULE)
  struct ist_info ist_info;
  EXPORT_SYMBOL(ist_info);
  #else
  struct ist_info ist_info;
  #endif
  
  #else
  struct cpuinfo_x86 boot_cpu_data __read_mostly;
  EXPORT_SYMBOL(boot_cpu_data);
  #endif
  
  
  #if !defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64)
  __visible unsigned long mmu_cr4_features __ro_after_init;
  #else
  __visible unsigned long mmu_cr4_features __ro_after_init = X86_CR4_PAE;
  #endif
  
  /* Boot loader ID and version as integers, for the benefit of proc_dointvec */
  int bootloader_type, bootloader_version;
  
  /*
   * Setup options
   */
  struct screen_info screen_info;
  EXPORT_SYMBOL(screen_info);
  struct edid_info edid_info;
  EXPORT_SYMBOL_GPL(edid_info);
  
  extern int root_mountflags;
  
  unsigned long saved_video_mode;
  
  #define RAMDISK_IMAGE_START_MASK	0x07FF
  #define RAMDISK_PROMPT_FLAG		0x8000
  #define RAMDISK_LOAD_FLAG		0x4000
  
  static char __initdata command_line[COMMAND_LINE_SIZE];
  #ifdef CONFIG_CMDLINE_BOOL
  static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
  #endif
  
  #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
  struct edd edd;
  #ifdef CONFIG_EDD_MODULE
  EXPORT_SYMBOL(edd);
  #endif
  /**
   * copy_edd() - Copy the BIOS EDD information
   *              from boot_params into a safe place.
   *
   */
  static inline void __init copy_edd(void)
  {
       memcpy(edd.mbr_signature, boot_params.edd_mbr_sig_buffer,
  	    sizeof(edd.mbr_signature));
       memcpy(edd.edd_info, boot_params.eddbuf, sizeof(edd.edd_info));
       edd.mbr_signature_nr = boot_params.edd_mbr_sig_buf_entries;
       edd.edd_info_nr = boot_params.eddbuf_entries;
  }
  #else
  static inline void __init copy_edd(void)
  {
  }
  #endif
  
  void * __init extend_brk(size_t size, size_t align)
  {
  	size_t mask = align - 1;
  	void *ret;
  
  	BUG_ON(_brk_start == 0);
  	BUG_ON(align & mask);
  
  	_brk_end = (_brk_end + mask) & ~mask;
  	BUG_ON((char *)(_brk_end + size) > __brk_limit);
  
  	ret = (void *)_brk_end;
  	_brk_end += size;
  
  	memset(ret, 0, size);
  
  	return ret;
  }
  
  #ifdef CONFIG_X86_32
  static void __init cleanup_highmap(void)
  {
  }
  #endif
  
  static void __init reserve_brk(void)
  {
  	if (_brk_end > _brk_start)
  		memblock_reserve(__pa_symbol(_brk_start),
  				 _brk_end - _brk_start);
  
  	/* Mark brk area as locked down and no longer taking any
  	   new allocations */
  	_brk_start = 0;
  }
  
  u64 relocated_ramdisk;
  
  #ifdef CONFIG_BLK_DEV_INITRD
  
  static u64 __init get_ramdisk_image(void)
  {
  	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
  
  	ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
  
  	return ramdisk_image;
  }
  static u64 __init get_ramdisk_size(void)
  {
  	u64 ramdisk_size = boot_params.hdr.ramdisk_size;
  
  	ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
  
  	return ramdisk_size;
  }
  
  static void __init relocate_initrd(void)
  {
  	/* Assume only end is not page aligned */
  	u64 ramdisk_image = get_ramdisk_image();
  	u64 ramdisk_size  = get_ramdisk_size();
  	u64 area_size     = PAGE_ALIGN(ramdisk_size);
  
  	/* We need to move the initrd down into directly mapped mem */
  	relocated_ramdisk = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
  						   area_size, PAGE_SIZE);
  
  	if (!relocated_ramdisk)
  		panic("Cannot find place for new RAMDISK of size %lld\n",
  		      ramdisk_size);
  
  	/* Note: this includes all the mem currently occupied by
  	   the initrd, we rely on that fact to keep the data intact. */
  	memblock_reserve(relocated_ramdisk, area_size);
  	initrd_start = relocated_ramdisk + PAGE_OFFSET;
  	initrd_end   = initrd_start + ramdisk_size;
  	printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
  	       relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
  
  	copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
  
  	printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
  		" [mem %#010llx-%#010llx]\n",
  		ramdisk_image, ramdisk_image + ramdisk_size - 1,
  		relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
  }
  
  static void __init early_reserve_initrd(void)
  {
  	/* Assume only end is not page aligned */
  	u64 ramdisk_image = get_ramdisk_image();
  	u64 ramdisk_size  = get_ramdisk_size();
  	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
  
  	if (!boot_params.hdr.type_of_loader ||
  	    !ramdisk_image || !ramdisk_size)
  		return;		/* No initrd provided by bootloader */
  
  	memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
  }
  static void __init reserve_initrd(void)
  {
  	/* Assume only end is not page aligned */
  	u64 ramdisk_image = get_ramdisk_image();
  	u64 ramdisk_size  = get_ramdisk_size();
  	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
  	u64 mapped_size;
  
  	if (!boot_params.hdr.type_of_loader ||
  	    !ramdisk_image || !ramdisk_size)
  		return;		/* No initrd provided by bootloader */
  
  	initrd_start = 0;
  
  	mapped_size = memblock_mem_size(max_pfn_mapped);
  	if (ramdisk_size >= (mapped_size>>1))
  		panic("initrd too large to handle, "
  		       "disabling initrd (%lld needed, %lld available)\n",
  		       ramdisk_size, mapped_size>>1);
  
  	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
  			ramdisk_end - 1);
  
  	if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
  				PFN_DOWN(ramdisk_end))) {
  		/* All are mapped, easy case */
  		initrd_start = ramdisk_image + PAGE_OFFSET;
  		initrd_end = initrd_start + ramdisk_size;
  		return;
  	}
  
  	relocate_initrd();
  
  	memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
  }
  
  #else
  static void __init early_reserve_initrd(void)
  {
  }
  static void __init reserve_initrd(void)
  {
  }
  #endif /* CONFIG_BLK_DEV_INITRD */
  
  static void __init parse_setup_data(void)
  {
  	struct setup_data *data;
  	u64 pa_data, pa_next;
  
  	pa_data = boot_params.hdr.setup_data;
  	while (pa_data) {
  		u32 data_len, data_type;
  
  		data = early_memremap(pa_data, sizeof(*data));
  		data_len = data->len + sizeof(struct setup_data);
  		data_type = data->type;
  		pa_next = data->next;
  		early_memunmap(data, sizeof(*data));
  
  		switch (data_type) {
  		case SETUP_E820_EXT:
  			e820__memory_setup_extended(pa_data, data_len);
  			break;
  		case SETUP_DTB:
  			add_dtb(pa_data);
  			break;
  		case SETUP_EFI:
  			parse_efi_setup(pa_data, data_len);
  			break;
  		default:
  			break;
  		}
  		pa_data = pa_next;
  	}
  }
  
  static void __init memblock_x86_reserve_range_setup_data(void)
  {
  	struct setup_data *data;
  	u64 pa_data;
  
  	pa_data = boot_params.hdr.setup_data;
  	while (pa_data) {
  		data = early_memremap(pa_data, sizeof(*data));
  		memblock_reserve(pa_data, sizeof(*data) + data->len);
  		pa_data = data->next;
  		early_memunmap(data, sizeof(*data));
  	}
  }
  
  /*
   * --------- Crashkernel reservation ------------------------------
   */
  
  #ifdef CONFIG_KEXEC_CORE
  
  /* 16M alignment for crash kernel regions */
  #define CRASH_ALIGN		(16 << 20)
  
  /*
   * Keep the crash kernel below this limit.  On 32 bits earlier kernels
   * would limit the kernel to the low 512 MiB due to mapping restrictions.
   * On 64bit, old kexec-tools need to under 896MiB.
   */
  #ifdef CONFIG_X86_32
  # define CRASH_ADDR_LOW_MAX	(512 << 20)
  # define CRASH_ADDR_HIGH_MAX	(512 << 20)
  #else
  # define CRASH_ADDR_LOW_MAX	(896UL << 20)
  # define CRASH_ADDR_HIGH_MAX	MAXMEM
  #endif
  
  static int __init reserve_crashkernel_low(void)
  {
  #ifdef CONFIG_X86_64
  	unsigned long long base, low_base = 0, low_size = 0;
  	unsigned long total_low_mem;
  	int ret;
  
  	total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));
  
  	/* crashkernel=Y,low */
  	ret = parse_crashkernel_low(boot_command_line, total_low_mem, &low_size, &base);
  	if (ret) {
  		/*
  		 * two parts from lib/swiotlb.c:
  		 * -swiotlb size: user-specified with swiotlb= or default.
  		 *
  		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
  		 * to 8M for other buffers that may need to stay low too. Also
  		 * make sure we allocate enough extra low memory so that we
  		 * don't run out of DMA buffers for 32-bit devices.
  		 */
  		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
  	} else {
  		/* passed with crashkernel=0,low ? */
  		if (!low_size)
  			return 0;
  	}
  
  	low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
  	if (!low_base) {
  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
  		       (unsigned long)(low_size >> 20));
  		return -ENOMEM;
  	}
  
  	ret = memblock_reserve(low_base, low_size);
  	if (ret) {
  		pr_err("%s: Error reserving crashkernel low memblock.\n", __func__);
  		return ret;
  	}
  
  	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (System low RAM: %ldMB)\n",
  		(unsigned long)(low_size >> 20),
  		(unsigned long)(low_base >> 20),
  		(unsigned long)(total_low_mem >> 20));
  
  	crashk_low_res.start = low_base;
  	crashk_low_res.end   = low_base + low_size - 1;
  	insert_resource(&iomem_resource, &crashk_low_res);
  #endif
  	return 0;
  }
  
  static void __init reserve_crashkernel(void)
  {
  	unsigned long long crash_size, crash_base, total_mem;
  	bool high = false;
  	int ret;
  
  	total_mem = memblock_phys_mem_size();
  
  	/* crashkernel=XM */
  	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
  	if (ret != 0 || crash_size <= 0) {
  		/* crashkernel=X,high */
  		ret = parse_crashkernel_high(boot_command_line, total_mem,
  					     &crash_size, &crash_base);
  		if (ret != 0 || crash_size <= 0)
  			return;
  		high = true;
  	}
  
  	if (xen_pv_domain()) {
  		pr_info("Ignoring crashkernel for a Xen PV domain\n");
  		return;
  	}
  
  	/* 0 means: find the address automatically */
  	if (crash_base <= 0) {
  		/*
  		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
  		 * as old kexec-tools loads bzImage below that, unless
  		 * "crashkernel=size[KMG],high" is specified.
  		 */
  		crash_base = memblock_find_in_range(CRASH_ALIGN,
  						    high ? CRASH_ADDR_HIGH_MAX
  							 : CRASH_ADDR_LOW_MAX,
  						    crash_size, CRASH_ALIGN);
  		if (!crash_base) {
  			pr_info("crashkernel reservation failed - No suitable area found.\n");
  			return;
  		}
  
  	} else {
  		unsigned long long start;
  
  		start = memblock_find_in_range(crash_base,
  					       crash_base + crash_size,
  					       crash_size, 1 << 20);
  		if (start != crash_base) {
  			pr_info("crashkernel reservation failed - memory is in use.\n");
  			return;
  		}
  	}
  	ret = memblock_reserve(crash_base, crash_size);
  	if (ret) {
  		pr_err("%s: Error reserving crashkernel memblock.\n", __func__);
  		return;
  	}
  
  	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
  		memblock_free(crash_base, crash_size);
  		return;
  	}
  
  	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
  		(unsigned long)(crash_size >> 20),
  		(unsigned long)(crash_base >> 20),
  		(unsigned long)(total_mem >> 20));
  
  	crashk_res.start = crash_base;
  	crashk_res.end   = crash_base + crash_size - 1;
  	insert_resource(&iomem_resource, &crashk_res);
  }
  #else
  static void __init reserve_crashkernel(void)
  {
  }
  #endif
  
  static struct resource standard_io_resources[] = {
  	{ .name = "dma1", .start = 0x00, .end = 0x1f,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "pic1", .start = 0x20, .end = 0x21,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "timer0", .start = 0x40, .end = 0x43,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "timer1", .start = 0x50, .end = 0x53,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "keyboard", .start = 0x60, .end = 0x60,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "keyboard", .start = 0x64, .end = 0x64,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "dma page reg", .start = 0x80, .end = 0x8f,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "pic2", .start = 0xa0, .end = 0xa1,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "dma2", .start = 0xc0, .end = 0xdf,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO },
  	{ .name = "fpu", .start = 0xf0, .end = 0xff,
  		.flags = IORESOURCE_BUSY | IORESOURCE_IO }
  };
  
  void __init reserve_standard_io_resources(void)
  {
  	int i;
  
  	/* request I/O space for devices used on all i[345]86 PCs */
  	for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
  		request_resource(&ioport_resource, &standard_io_resources[i]);
  
  }
  
  static __init void reserve_ibft_region(void)
  {
  	unsigned long addr, size = 0;
  
  	addr = find_ibft_region(&size);
  
  	if (size)
  		memblock_reserve(addr, size);
  }
  
  static bool __init snb_gfx_workaround_needed(void)
  {
  #ifdef CONFIG_PCI
  	int i;
  	u16 vendor, devid;
  	static const __initconst u16 snb_ids[] = {
  		0x0102,
  		0x0112,
  		0x0122,
  		0x0106,
  		0x0116,
  		0x0126,
  		0x010a,
  	};
  
  	/* Assume no if something weird is going on with PCI */
  	if (!early_pci_allowed())
  		return false;
  
  	vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
  	if (vendor != 0x8086)
  		return false;
  
  	devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
  	for (i = 0; i < ARRAY_SIZE(snb_ids); i++)
  		if (devid == snb_ids[i])
  			return true;
  #endif
  
  	return false;
  }
  
  /*
   * Sandy Bridge graphics has trouble with certain ranges, exclude
   * them from allocation.
   */
  static void __init trim_snb_memory(void)
  {
  	static const __initconst unsigned long bad_pages[] = {
  		0x20050000,
  		0x20110000,
  		0x20130000,
  		0x20138000,
  		0x40004000,
  	};
  	int i;
  
  	if (!snb_gfx_workaround_needed())
  		return;
  
  	printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");
  
  	/*
  	 * Reserve all memory below the 1 MB mark that has not
  	 * already been reserved.
  	 */
  	memblock_reserve(0, 1<<20);
  	
  	for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
  		if (memblock_reserve(bad_pages[i], PAGE_SIZE))
  			printk(KERN_WARNING "failed to reserve 0x%08lx\n",
  			       bad_pages[i]);
  	}
  }
  
  /*
   * Here we put platform-specific memory range workarounds, i.e.
   * memory known to be corrupt or otherwise in need to be reserved on
   * specific platforms.
   *
   * If this gets used more widely it could use a real dispatch mechanism.
   */
  static void __init trim_platform_memory_ranges(void)
  {
  	trim_snb_memory();
  }
  
  static void __init trim_bios_range(void)
  {
  	/*
  	 * A special case is the first 4Kb of memory;
  	 * This is a BIOS owned area, not kernel ram, but generally
  	 * not listed as such in the E820 table.
  	 *
  	 * This typically reserves additional memory (64KiB by default)
  	 * since some BIOSes are known to corrupt low memory.  See the
  	 * Kconfig help text for X86_RESERVE_LOW.
  	 */
  	e820__range_update(0, PAGE_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);
  
  	/*
  	 * special case: Some BIOSen report the PC BIOS
  	 * area (640->1Mb) as ram even though it is not.
  	 * take them out.
  	 */
  	e820__range_remove(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_TYPE_RAM, 1);
  
  	e820__update_table(e820_table);
  }
  
  /* called before trim_bios_range() to spare extra sanitize */
  static void __init e820_add_kernel_range(void)
  {
  	u64 start = __pa_symbol(_text);
  	u64 size = __pa_symbol(_end) - start;
  
  	/*
  	 * Complain if .text .data and .bss are not marked as E820_TYPE_RAM and
  	 * attempt to fix it by adding the range. We may have a confused BIOS,
  	 * or the user may have used memmap=exactmap or memmap=xxM$yyM to
  	 * exclude kernel range. If we really are running on top non-RAM,
  	 * we will crash later anyways.
  	 */
  	if (e820__mapped_all(start, start + size, E820_TYPE_RAM))
  		return;
  
  	pr_warn(".text .data .bss are not marked as E820_TYPE_RAM!\n");
  	e820__range_remove(start, size, E820_TYPE_RAM, 0);
  	e820__range_add(start, size, E820_TYPE_RAM);
  }
  
  static unsigned reserve_low = CONFIG_X86_RESERVE_LOW << 10;
  
  static int __init parse_reservelow(char *p)
  {
  	unsigned long long size;
  
  	if (!p)
  		return -EINVAL;
  
  	size = memparse(p, &p);
  
  	if (size < 4096)
  		size = 4096;
  
  	if (size > 640*1024)
  		size = 640*1024;
  
  	reserve_low = size;
  
  	return 0;
  }
  
  early_param("reservelow", parse_reservelow);
  
  static void __init trim_low_memory_range(void)
  {
  	memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
  }
  	
  /*
   * Dump out kernel offset information on panic.
   */
  static int
  dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
  {
  	if (kaslr_enabled()) {
  		pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
  			 kaslr_offset(),
  			 __START_KERNEL,
  			 __START_KERNEL_map,
  			 MODULES_VADDR-1);
  	} else {
  		pr_emerg("Kernel Offset: disabled\n");
  	}
  
  	return 0;
  }
  
  /*
   * Determine if we were loaded by an EFI loader.  If so, then we have also been
   * passed the efi memmap, systab, etc., so we should use these data structures
   * for initialization.  Note, the efi init code path is determined by the
   * global efi_enabled. This allows the same kernel image to be used on existing
   * systems (with a traditional BIOS) as well as on EFI systems.
   */
  /*
   * setup_arch - architecture-specific boot-time initializations
   *
   * Note: On x86_64, fixmaps are ready for use even before this is called.
   */
  
  void __init setup_arch(char **cmdline_p)
  {
  	memblock_reserve(__pa_symbol(_text),
  			 (unsigned long)__bss_stop - (unsigned long)_text);
  
  	/*
  	 * Make sure page 0 is always reserved because on systems with
  	 * L1TF its contents can be leaked to user processes.
  	 */
  	memblock_reserve(0, PAGE_SIZE);
  
  	early_reserve_initrd();
  
  	/*
  	 * 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.
  	 */
  
  #ifdef CONFIG_X86_32
  	memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
  
  	/*
  	 * copy kernel address range established so far and switch
  	 * to the proper swapper page table
  	 */
  	clone_pgd_range(swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
  			initial_page_table + KERNEL_PGD_BOUNDARY,
  			KERNEL_PGD_PTRS);
  
  	load_cr3(swapper_pg_dir);
  	/*
  	 * Note: Quark X1000 CPUs advertise PGE incorrectly and require
  	 * a cr3 based tlb flush, so the following __flush_tlb_all()
  	 * will not flush anything because the cpu quirk which clears
  	 * X86_FEATURE_PGE has not been invoked yet. Though due to the
  	 * load_cr3() above the TLB has been flushed already. The
  	 * quirk is invoked before subsequent calls to __flush_tlb_all()
  	 * so proper operation is guaranteed.
  	 */
  	__flush_tlb_all();
  #else
  	printk(KERN_INFO "Command line: %s\n", boot_command_line);
  	boot_cpu_data.x86_phys_bits = MAX_PHYSMEM_BITS;
  #endif
  
  	/*
  	 * If we have OLPC OFW, we might end up relocating the fixmap due to
  	 * reserve_top(), so do this before touching the ioremap area.
  	 */
  	olpc_ofw_detect();
  
  	idt_setup_early_traps();
  	early_cpu_init();
  	arch_init_ideal_nops();
  	jump_label_init();
  	early_ioremap_init();
  
  	setup_olpc_ofw_pgd();
  
  	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
  	screen_info = boot_params.screen_info;
  	edid_info = boot_params.edid_info;
  #ifdef CONFIG_X86_32
  	apm_info.bios = boot_params.apm_bios_info;
  	ist_info = boot_params.ist_info;
  #endif
  	saved_video_mode = boot_params.hdr.vid_mode;
  	bootloader_type = boot_params.hdr.type_of_loader;
  	if ((bootloader_type >> 4) == 0xe) {
  		bootloader_type &= 0xf;
  		bootloader_type |= (boot_params.hdr.ext_loader_type+0x10) << 4;
  	}
  	bootloader_version  = bootloader_type & 0xf;
  	bootloader_version |= boot_params.hdr.ext_loader_ver << 4;
  
  #ifdef CONFIG_BLK_DEV_RAM
  	rd_image_start = boot_params.hdr.ram_size & RAMDISK_IMAGE_START_MASK;
  	rd_prompt = ((boot_params.hdr.ram_size & RAMDISK_PROMPT_FLAG) != 0);
  	rd_doload = ((boot_params.hdr.ram_size & RAMDISK_LOAD_FLAG) != 0);
  #endif
  #ifdef CONFIG_EFI
  	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
  		     EFI32_LOADER_SIGNATURE, 4)) {
  		set_bit(EFI_BOOT, &efi.flags);
  	} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
  		     EFI64_LOADER_SIGNATURE, 4)) {
  		set_bit(EFI_BOOT, &efi.flags);
  		set_bit(EFI_64BIT, &efi.flags);
  	}
  #endif
  
  	x86_init.oem.arch_setup();
  
  	iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
  	e820__memory_setup();
  	parse_setup_data();
  
  	copy_edd();
  
  	if (!boot_params.hdr.root_flags)
  		root_mountflags &= ~MS_RDONLY;
  	init_mm.start_code = (unsigned long) _text;
  	init_mm.end_code = (unsigned long) _etext;
  	init_mm.end_data = (unsigned long) _edata;
  	init_mm.brk = _brk_end;
  
  	mpx_mm_init(&init_mm);
  
  	code_resource.start = __pa_symbol(_text);
  	code_resource.end = __pa_symbol(_etext)-1;
  	data_resource.start = __pa_symbol(_etext);
  	data_resource.end = __pa_symbol(_edata)-1;
  	bss_resource.start = __pa_symbol(__bss_start);
  	bss_resource.end = __pa_symbol(__bss_stop)-1;
  
  #ifdef CONFIG_CMDLINE_BOOL
  #ifdef CONFIG_CMDLINE_OVERRIDE
  	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
  #else
  	if (builtin_cmdline[0]) {
  		/* append boot loader cmdline to builtin */
  		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
  		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
  		strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
  	}
  #endif
  #endif
  
  	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
  	*cmdline_p = command_line;
  
  	/*
  	 * x86_configure_nx() is called before parse_early_param() to detect
  	 * whether hardware doesn't support NX (so that the early EHCI debug
  	 * console setup can safely call set_fixmap()). It may then be called
  	 * again from within noexec_setup() during parsing early parameters
  	 * to honor the respective command line option.
  	 */
  	x86_configure_nx();
  
  	parse_early_param();
  
  	if (efi_enabled(EFI_BOOT))
  		efi_memblock_x86_reserve_range();
  #ifdef CONFIG_MEMORY_HOTPLUG
  	/*
  	 * Memory used by the kernel cannot be hot-removed because Linux
  	 * cannot migrate the kernel pages. When memory hotplug is
  	 * enabled, we should prevent memblock from allocating memory
  	 * for the kernel.
  	 *
  	 * ACPI SRAT records all hotpluggable memory ranges. But before
  	 * SRAT is parsed, we don't know about it.
  	 *
  	 * The kernel image is loaded into memory at very early time. We
  	 * cannot prevent this anyway. So on NUMA system, we set any
  	 * node the kernel resides in as un-hotpluggable.
  	 *
  	 * Since on modern servers, one node could have double-digit
  	 * gigabytes memory, we can assume the memory around the kernel
  	 * image is also un-hotpluggable. So before SRAT is parsed, just
  	 * allocate memory near the kernel image to try the best to keep
  	 * the kernel away from hotpluggable memory.
  	 */
  	if (movable_node_is_enabled())
  		memblock_set_bottom_up(true);
  #endif
  
  	x86_report_nx();
  
  	/* after early param, so could get panic from serial */
  	memblock_x86_reserve_range_setup_data();
  
  	if (acpi_mps_check()) {
  #ifdef CONFIG_X86_LOCAL_APIC
  		disable_apic = 1;
  #endif
  		setup_clear_cpu_cap(X86_FEATURE_APIC);
  	}
  
  	e820__reserve_setup_data();
  	e820__finish_early_params();
  
  	if (efi_enabled(EFI_BOOT))
  		efi_init();
  
  	dmi_scan_machine();
  	dmi_memdev_walk();
  	dmi_set_dump_stack_arch_desc();
  
  	/*
  	 * VMware detection requires dmi to be available, so this
  	 * needs to be done after dmi_scan_machine(), for the boot CPU.
  	 */
  	init_hypervisor_platform();
  
  	tsc_early_init();
  	x86_init.resources.probe_roms();
  
  	/* after parse_early_param, so could debug it */
  	insert_resource(&iomem_resource, &code_resource);
  	insert_resource(&iomem_resource, &data_resource);
  	insert_resource(&iomem_resource, &bss_resource);
  
  	e820_add_kernel_range();
  	trim_bios_range();
  #ifdef CONFIG_X86_32
  	if (ppro_with_ram_bug()) {
  		e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM,
  				  E820_TYPE_RESERVED);
  		e820__update_table(e820_table);
  		printk(KERN_INFO "fixed physical RAM map:\n");
  		e820__print_table("bad_ppro");
  	}
  #else
  	early_gart_iommu_check();
  #endif
  
  	/*
  	 * partially used pages are not usable - thus
  	 * we are rounding upwards:
  	 */
  	max_pfn = e820__end_of_ram_pfn();
  
  	/* update e820 for memory not covered by WB MTRRs */
  	mtrr_bp_init();
  	if (mtrr_trim_uncached_memory(max_pfn))
  		max_pfn = e820__end_of_ram_pfn();
  
  	max_possible_pfn = max_pfn;
  
  	/*
  	 * This call is required when the CPU does not support PAT. If
  	 * mtrr_bp_init() invoked it already via pat_init() the call has no
  	 * effect.
  	 */
  	init_cache_modes();
  
  	/*
  	 * Define random base addresses for memory sections after max_pfn is
  	 * defined and before each memory section base is used.
  	 */
  	kernel_randomize_memory();
  
  #ifdef CONFIG_X86_32
  	/* max_low_pfn get updated here */
  	find_low_pfn_range();
  #else
  	check_x2apic();
  
  	/* How many end-of-memory variables you have, grandma! */
  	/* need this before calling reserve_initrd */
  	if (max_pfn > (1UL<<(32 - PAGE_SHIFT)))
  		max_low_pfn = e820__end_of_low_ram_pfn();
  	else
  		max_low_pfn = max_pfn;
  
  	high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
  #endif
  
  	/*
  	 * Find and reserve possible boot-time SMP configuration:
  	 */
  	find_smp_config();
  
  	reserve_ibft_region();
  
  	early_alloc_pgt_buf();
  
  	/*
  	 * Need to conclude brk, before e820__memblock_setup()
  	 *  it could use memblock_find_in_range, could overlap with
  	 *  brk area.
  	 */
  	reserve_brk();
  
  	cleanup_highmap();
  
  	memblock_set_current_limit(ISA_END_ADDRESS);
  	e820__memblock_setup();
  
  	reserve_bios_regions();
  
  	if (efi_enabled(EFI_MEMMAP)) {
  		efi_fake_memmap();
  		efi_find_mirror();
  		efi_esrt_init();
  
  		/*
  		 * The EFI specification says that boot service code won't be
  		 * called after ExitBootServices(). This is, in fact, a lie.
  		 */
  		efi_reserve_boot_services();
  	}
  
  	/* preallocate 4k for mptable mpc */
  	e820__memblock_alloc_reserved_mpc_new();
  
  #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
  	setup_bios_corruption_check();
  #endif
  
  #ifdef CONFIG_X86_32
  	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
  			(max_pfn_mapped<<PAGE_SHIFT) - 1);
  #endif
  
  	reserve_real_mode();
  
  	trim_platform_memory_ranges();
  	trim_low_memory_range();
  
  	init_mem_mapping();
  
  	idt_setup_early_pf();
  
  	/*
  	 * Update mmu_cr4_features (and, indirectly, trampoline_cr4_features)
  	 * with the current CR4 value.  This may not be necessary, but
  	 * auditing all the early-boot CR4 manipulation would be needed to
  	 * rule it out.
  	 *
  	 * Mask off features that don't work outside long mode (just
  	 * PCIDE for now).
  	 */
  	mmu_cr4_features = __read_cr4() & ~X86_CR4_PCIDE;
  
  	memblock_set_current_limit(get_max_mapped());
  
  	/*
  	 * NOTE: On x86-32, only from this point on, fixmaps are ready for use.
  	 */
  
  #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
  	if (init_ohci1394_dma_early)
  		init_ohci1394_dma_on_all_controllers();
  #endif
  	/* Allocate bigger log buffer */
  	setup_log_buf(1);
  
  	if (efi_enabled(EFI_BOOT)) {
  		switch (boot_params.secure_boot) {
  		case efi_secureboot_mode_disabled:
  			pr_info("Secure boot disabled\n");
  			break;
  		case efi_secureboot_mode_enabled:
  			pr_info("Secure boot enabled\n");
  			break;
  		default:
  			pr_info("Secure boot could not be determined\n");
  			break;
  		}
  	}
  
  	reserve_initrd();
  
  	acpi_table_upgrade();
  
  	vsmp_init();
  
  	io_delay_init();
  
  	early_platform_quirks();
  
  	/*
  	 * Parse the ACPI tables for possible boot-time SMP configuration.
  	 */
  	acpi_boot_table_init();
  
  	early_acpi_boot_init();
  
  	initmem_init();
  	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
  
  	/*
  	 * Reserve memory for crash kernel after SRAT is parsed so that it
  	 * won't consume hotpluggable memory.
  	 */
  	reserve_crashkernel();
  
  	memblock_find_dma_reserve();
  
  	if (!early_xdbc_setup_hardware())
  		early_xdbc_register_console();
  
  	x86_init.paging.pagetable_init();
  
  	kasan_init();
  
  	/*
  	 * Sync back kernel address range.
  	 *
  	 * FIXME: Can the later sync in setup_cpu_entry_areas() replace
  	 * this call?
  	 */
  	sync_initial_page_table();
  
  	tboot_probe();
  
  	map_vsyscall();
  
  	generic_apic_probe();
  
  	early_quirks();
  
  	/*
  	 * Read APIC and some other early information from ACPI tables.
  	 */
  	acpi_boot_init();
  	sfi_init();
  	x86_dtb_init();
  
  	/*
  	 * get boot-time SMP configuration:
  	 */
  	get_smp_config();
  
  	/*
  	 * Systems w/o ACPI and mptables might not have it mapped the local
  	 * APIC yet, but prefill_possible_map() might need to access it.
  	 */
  	init_apic_mappings();
  
  	prefill_possible_map();
  
  	init_cpu_to_node();
  
  	io_apic_init_mappings();
  
  	x86_init.hyper.guest_late_init();
  
  	e820__reserve_resources();
  	e820__register_nosave_regions(max_pfn);
  
  	x86_init.resources.reserve_resources();
  
  	e820__setup_pci_gap();
  
  #ifdef CONFIG_VT
  #if defined(CONFIG_VGA_CONSOLE)
  	if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
  		conswitchp = &vga_con;
  #elif defined(CONFIG_DUMMY_CONSOLE)
  	conswitchp = &dummy_con;
  #endif
  #endif
  	x86_init.oem.banner();
  
  	x86_init.timers.wallclock_init();
  
  	mcheck_init();
  
  	register_refined_jiffies(CLOCK_TICK_RATE);
  
  #ifdef CONFIG_EFI
  	if (efi_enabled(EFI_BOOT))
  		efi_apply_memmap_quirks();
  #endif
  
  	unwind_init();
  }
  
  /*
   * From boot protocol 2.14 onwards we expect the bootloader to set the
   * version to "0x8000 | <used version>". In case we find a version >= 2.14
   * without the 0x8000 we assume the boot loader supports 2.13 only and
   * reset the version accordingly. The 0x8000 flag is removed in any case.
   */
  void __init x86_verify_bootdata_version(void)
  {
  	if (boot_params.hdr.version & VERSION_WRITTEN)
  		boot_params.hdr.version &= ~VERSION_WRITTEN;
  	else if (boot_params.hdr.version >= 0x020e)
  		boot_params.hdr.version = 0x020d;
  
  	if (boot_params.hdr.version < 0x020e)
  		boot_params.hdr.acpi_rsdp_addr = 0;
  }
  
  #ifdef CONFIG_X86_32
  
  static struct resource video_ram_resource = {
  	.name	= "Video RAM area",
  	.start	= 0xa0000,
  	.end	= 0xbffff,
  	.flags	= IORESOURCE_BUSY | IORESOURCE_MEM
  };
  
  void __init i386_reserve_resources(void)
  {
  	request_resource(&iomem_resource, &video_ram_resource);
  	reserve_standard_io_resources();
  }
  
  #endif /* CONFIG_X86_32 */
  
  static struct notifier_block kernel_offset_notifier = {
  	.notifier_call = dump_kernel_offset
  };
  
  static int __init register_kernel_offset_dumper(void)
  {
  	atomic_notifier_chain_register(&panic_notifier_list,
  					&kernel_offset_notifier);
  	return 0;
  }
  __initcall(register_kernel_offset_dumper);
  