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e820_64.c

/* 
 * Handle the memory map.
 * The functions here do the job until bootmem takes over.
 *
 *  Getting sanitize_e820_map() in sync with i386 version by applying change:
 *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
 *     Alex Achenbach <xela@slit.de>, December 2002.
 *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/string.h>
#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/pfn.h>

#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/setup.h>
#include <asm/sections.h>

struct e820map e820;

/* 
 * PFN of last memory page.
 */
unsigned long end_pfn; 
EXPORT_SYMBOL(end_pfn);

/* 
 * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
 * The direct mapping extends to end_pfn_map, so that we can directly access
 * apertures, ACPI and other tables without having to play with fixmaps.
 */ 
unsigned long end_pfn_map; 

/* 
 * Last pfn which the user wants to use.
 */
static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;

extern struct resource code_resource, data_resource, bss_resource;

/* Check for some hardcoded bad areas that early boot is not allowed to touch */ 
static inline int bad_addr(unsigned long *addrp, unsigned long size)
{ 
      unsigned long addr = *addrp, last = addr + size; 

      /* various gunk below that needed for SMP startup */
      if (addr < 0x8000) { 
            *addrp = PAGE_ALIGN(0x8000);
            return 1; 
      }

      /* direct mapping tables of the kernel */
      if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { 
            *addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
            return 1;
      } 

      /* initrd */ 
#ifdef CONFIG_BLK_DEV_INITRD
      if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
            unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
            unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
            unsigned long ramdisk_end   = ramdisk_image+ramdisk_size;

            if (last >= ramdisk_image && addr < ramdisk_end) {
                  *addrp = PAGE_ALIGN(ramdisk_end);
                  return 1;
            }
      } 
#endif
      /* kernel code */
      if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
            *addrp = PAGE_ALIGN(__pa_symbol(&_end));
            return 1;
      }

      if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
            *addrp = PAGE_ALIGN(ebda_addr + ebda_size);
            return 1;
      }

#ifdef CONFIG_NUMA
      /* NUMA memory to node map */
      if (last >= nodemap_addr && addr < nodemap_addr + nodemap_size) {
            *addrp = nodemap_addr + nodemap_size;
            return 1;
      }
#endif
      /* XXX ramdisk image here? */ 
      return 0;
} 

/*
 * This function checks if any part of the range <start,end> is mapped
 * with type.
 */
int
e820_any_mapped(unsigned long start, unsigned long end, unsigned type)
{ 
      int i;
      for (i = 0; i < e820.nr_map; i++) { 
            struct e820entry *ei = &e820.map[i]; 
            if (type && ei->type != type) 
                  continue;
            if (ei->addr >= end || ei->addr + ei->size <= start)
                  continue; 
            return 1; 
      } 
      return 0;
}
EXPORT_SYMBOL_GPL(e820_any_mapped);

/*
 * This function checks if the entire range <start,end> is mapped with type.
 *
 * Note: this function only works correct if the e820 table is sorted and
 * not-overlapping, which is the case
 */
int __init e820_all_mapped(unsigned long start, unsigned long end, unsigned type)
{
      int i;
      for (i = 0; i < e820.nr_map; i++) {
            struct e820entry *ei = &e820.map[i];
            if (type && ei->type != type)
                  continue;
            /* is the region (part) in overlap with the current region ?*/
            if (ei->addr >= end || ei->addr + ei->size <= start)
                  continue;

            /* if the region is at the beginning of <start,end> we move
             * start to the end of the region since it's ok until there
             */
            if (ei->addr <= start)
                  start = ei->addr + ei->size;
            /* if start is now at or beyond end, we're done, full coverage */
            if (start >= end)
                  return 1; /* we're done */
      }
      return 0;
}

/* 
 * Find a free area in a specific range. 
 */ 
unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size) 
{ 
      int i; 
      for (i = 0; i < e820.nr_map; i++) { 
            struct e820entry *ei = &e820.map[i]; 
            unsigned long addr = ei->addr, last; 
            if (ei->type != E820_RAM) 
                  continue; 
            if (addr < start) 
                  addr = start;
            if (addr > ei->addr + ei->size) 
                  continue; 
            while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
                  ;
            last = PAGE_ALIGN(addr) + size;
            if (last > ei->addr + ei->size)
                  continue;
            if (last > end) 
                  continue;
            return addr; 
      } 
      return -1UL;            
} 

/*
 * Find the highest page frame number we have available
 */
unsigned long __init e820_end_of_ram(void)
{
      unsigned long end_pfn = 0;
      end_pfn = find_max_pfn_with_active_regions();
      
      if (end_pfn > end_pfn_map) 
            end_pfn_map = end_pfn;
      if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
            end_pfn_map = MAXMEM>>PAGE_SHIFT;
      if (end_pfn > end_user_pfn)
            end_pfn = end_user_pfn;
      if (end_pfn > end_pfn_map) 
            end_pfn = end_pfn_map; 

      printk("end_pfn_map = %lu\n", end_pfn_map);
      return end_pfn;   
}

/*
 * Mark e820 reserved areas as busy for the resource manager.
 */
void __init e820_reserve_resources(void)
{
      int i;
      for (i = 0; i < e820.nr_map; i++) {
            struct resource *res;
            res = alloc_bootmem_low(sizeof(struct resource));
            switch (e820.map[i].type) {
            case E820_RAM:    res->name = "System RAM"; break;
            case E820_ACPI:   res->name = "ACPI Tables"; break;
            case E820_NVS:    res->name = "ACPI Non-volatile Storage"; break;
            default:    res->name = "reserved";
            }
            res->start = e820.map[i].addr;
            res->end = res->start + e820.map[i].size - 1;
            res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
            request_resource(&iomem_resource, res);
            if (e820.map[i].type == E820_RAM) {
                  /*
                   *  We don't know which RAM region contains kernel data,
                   *  so we try it repeatedly and let the resource manager
                   *  test it.
                   */
                  request_resource(res, &code_resource);
                  request_resource(res, &data_resource);
                  request_resource(res, &bss_resource);
#ifdef CONFIG_KEXEC
                  if (crashk_res.start != crashk_res.end)
                        request_resource(res, &crashk_res);
#endif
            }
      }
}

/*
 * Find the ranges of physical addresses that do not correspond to
 * e820 RAM areas and mark the corresponding pages as nosave for software
 * suspend and suspend to RAM.
 *
 * This function requires the e820 map to be sorted and without any
 * overlapping entries and assumes the first e820 area to be RAM.
 */
void __init e820_mark_nosave_regions(void)
{
      int i;
      unsigned long paddr;

      paddr = round_down(e820.map[0].addr + e820.map[0].size, PAGE_SIZE);
      for (i = 1; i < e820.nr_map; i++) {
            struct e820entry *ei = &e820.map[i];

            if (paddr < ei->addr)
                  register_nosave_region(PFN_DOWN(paddr),
                                    PFN_UP(ei->addr));

            paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
            if (ei->type != E820_RAM)
                  register_nosave_region(PFN_UP(ei->addr),
                                    PFN_DOWN(paddr));

            if (paddr >= (end_pfn << PAGE_SHIFT))
                  break;
      }
}

/*
 * Finds an active region in the address range from start_pfn to end_pfn and
 * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
 */
static int __init e820_find_active_region(const struct e820entry *ei,
                                unsigned long start_pfn,
                                unsigned long end_pfn,
                                unsigned long *ei_startpfn,
                                unsigned long *ei_endpfn)
{
      *ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
      *ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;

      /* Skip map entries smaller than a page */
      if (*ei_startpfn >= *ei_endpfn)
            return 0;

      /* Check if end_pfn_map should be updated */
      if (ei->type != E820_RAM && *ei_endpfn > end_pfn_map)
            end_pfn_map = *ei_endpfn;

      /* Skip if map is outside the node */
      if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
                            *ei_startpfn >= end_pfn)
            return 0;

      /* Check for overlaps */
      if (*ei_startpfn < start_pfn)
            *ei_startpfn = start_pfn;
      if (*ei_endpfn > end_pfn)
            *ei_endpfn = end_pfn;

      /* Obey end_user_pfn to save on memmap */
      if (*ei_startpfn >= end_user_pfn)
            return 0;
      if (*ei_endpfn > end_user_pfn)
            *ei_endpfn = end_user_pfn;

      return 1;
}

/* Walk the e820 map and register active regions within a node */
void __init
e820_register_active_regions(int nid, unsigned long start_pfn,
                                          unsigned long end_pfn)
{
      unsigned long ei_startpfn;
      unsigned long ei_endpfn;
      int i;

      for (i = 0; i < e820.nr_map; i++)
            if (e820_find_active_region(&e820.map[i],
                                  start_pfn, end_pfn,
                                  &ei_startpfn, &ei_endpfn))
                  add_active_range(nid, ei_startpfn, ei_endpfn);
}

/* 
 * Add a memory region to the kernel e820 map.
 */ 
void __init add_memory_region(unsigned long start, unsigned long size, int type)
{
      int x = e820.nr_map;

      if (x == E820MAX) {
            printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
            return;
      }

      e820.map[x].addr = start;
      e820.map[x].size = size;
      e820.map[x].type = type;
      e820.nr_map++;
}

/*
 * Find the hole size (in bytes) in the memory range.
 * @start: starting address of the memory range to scan
 * @end: ending address of the memory range to scan
 */
unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
{
      unsigned long start_pfn = start >> PAGE_SHIFT;
      unsigned long end_pfn = end >> PAGE_SHIFT;
      unsigned long ei_startpfn;
      unsigned long ei_endpfn;
      unsigned long ram = 0;
      int i;

      for (i = 0; i < e820.nr_map; i++) {
            if (e820_find_active_region(&e820.map[i],
                                  start_pfn, end_pfn,
                                  &ei_startpfn, &ei_endpfn))
                  ram += ei_endpfn - ei_startpfn;
      }
      return end - start - (ram << PAGE_SHIFT);
}

void __init e820_print_map(char *who)
{
      int i;

      for (i = 0; i < e820.nr_map; i++) {
            printk(KERN_INFO " %s: %016Lx - %016Lx ", who,
                  (unsigned long long) e820.map[i].addr,
                  (unsigned long long) (e820.map[i].addr + e820.map[i].size));
            switch (e820.map[i].type) {
            case E820_RAM:    printk("(usable)\n");
                        break;
            case E820_RESERVED:
                        printk("(reserved)\n");
                        break;
            case E820_ACPI:
                        printk("(ACPI data)\n");
                        break;
            case E820_NVS:
                        printk("(ACPI NVS)\n");
                        break;
            default:    printk("type %u\n", e820.map[i].type);
                        break;
            }
      }
}

/*
 * Sanitize the BIOS e820 map.
 *
 * Some e820 responses include overlapping entries.  The following 
 * replaces the original e820 map with a new one, removing overlaps.
 *
 */
static int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
{
      struct change_member {
            struct e820entry *pbios; /* pointer to original bios entry */
            unsigned long long addr; /* address for this change point */
      };
      static struct change_member change_point_list[2*E820MAX] __initdata;
      static struct change_member *change_point[2*E820MAX] __initdata;
      static struct e820entry *overlap_list[E820MAX] __initdata;
      static struct e820entry new_bios[E820MAX] __initdata;
      struct change_member *change_tmp;
      unsigned long current_type, last_type;
      unsigned long long last_addr;
      int chgidx, still_changing;
      int overlap_entries;
      int new_bios_entry;
      int old_nr, new_nr, chg_nr;
      int i;

      /*
            Visually we're performing the following (1,2,3,4 = memory types)...

            Sample memory map (w/overlaps):
               ____22__________________
               ______________________4_
               ____1111________________
               _44_____________________
               11111111________________
               ____________________33__
               ___________44___________
               __________33333_________
               ______________22________
               ___________________2222_
               _________111111111______
               _____________________11_
               _________________4______

            Sanitized equivalent (no overlap):
               1_______________________
               _44_____________________
               ___1____________________
               ____22__________________
               ______11________________
               _________1______________
               __________3_____________
               ___________44___________
               _____________33_________
               _______________2________
               ________________1_______
               _________________4______
               ___________________2____
               ____________________33__
               ______________________4_
      */

      /* if there's only one memory region, don't bother */
      if (*pnr_map < 2)
            return -1;

      old_nr = *pnr_map;

      /* bail out if we find any unreasonable addresses in bios map */
      for (i=0; i<old_nr; i++)
            if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
                  return -1;

      /* create pointers for initial change-point information (for sorting) */
      for (i=0; i < 2*old_nr; i++)
            change_point[i] = &change_point_list[i];

      /* record all known change-points (starting and ending addresses),
         omitting those that are for empty memory regions */
      chgidx = 0;
      for (i=0; i < old_nr; i++)    {
            if (biosmap[i].size != 0) {
                  change_point[chgidx]->addr = biosmap[i].addr;
                  change_point[chgidx++]->pbios = &biosmap[i];
                  change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
                  change_point[chgidx++]->pbios = &biosmap[i];
            }
      }
      chg_nr = chgidx;

      /* sort change-point list by memory addresses (low -> high) */
      still_changing = 1;
      while (still_changing)  {
            still_changing = 0;
            for (i=1; i < chg_nr; i++)  {
                  /* if <current_addr> > <last_addr>, swap */
                  /* or, if current=<start_addr> & last=<end_addr>, swap */
                  if ((change_point[i]->addr < change_point[i-1]->addr) ||
                        ((change_point[i]->addr == change_point[i-1]->addr) &&
                         (change_point[i]->addr == change_point[i]->pbios->addr) &&
                         (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
                     )
                  {
                        change_tmp = change_point[i];
                        change_point[i] = change_point[i-1];
                        change_point[i-1] = change_tmp;
                        still_changing=1;
                  }
            }
      }

      /* create a new bios memory map, removing overlaps */
      overlap_entries=0;       /* number of entries in the overlap table */
      new_bios_entry=0;  /* index for creating new bios map entries */
      last_type = 0;           /* start with undefined memory type */
      last_addr = 0;           /* start with 0 as last starting address */
      /* loop through change-points, determining affect on the new bios map */
      for (chgidx=0; chgidx < chg_nr; chgidx++)
      {
            /* keep track of all overlapping bios entries */
            if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
            {
                  /* add map entry to overlap list (> 1 entry implies an overlap) */
                  overlap_list[overlap_entries++]=change_point[chgidx]->pbios;
            }
            else
            {
                  /* remove entry from list (order independent, so swap with last) */
                  for (i=0; i<overlap_entries; i++)
                  {
                        if (overlap_list[i] == change_point[chgidx]->pbios)
                              overlap_list[i] = overlap_list[overlap_entries-1];
                  }
                  overlap_entries--;
            }
            /* if there are overlapping entries, decide which "type" to use */
            /* (larger value takes precedence -- 1=usable, 2,3,4,4+=unusable) */
            current_type = 0;
            for (i=0; i<overlap_entries; i++)
                  if (overlap_list[i]->type > current_type)
                        current_type = overlap_list[i]->type;
            /* continue building up new bios map based on this information */
            if (current_type != last_type)      {
                  if (last_type != 0)      {
                        new_bios[new_bios_entry].size =
                              change_point[chgidx]->addr - last_addr;
                        /* move forward only if the new size was non-zero */
                        if (new_bios[new_bios_entry].size != 0)
                              if (++new_bios_entry >= E820MAX)
                                    break;      /* no more space left for new bios entries */
                  }
                  if (current_type != 0)  {
                        new_bios[new_bios_entry].addr = change_point[chgidx]->addr;
                        new_bios[new_bios_entry].type = current_type;
                        last_addr=change_point[chgidx]->addr;
                  }
                  last_type = current_type;
            }
      }
      new_nr = new_bios_entry;   /* retain count for new bios entries */

      /* copy new bios mapping into original location */
      memcpy(biosmap, new_bios, new_nr*sizeof(struct e820entry));
      *pnr_map = new_nr;

      return 0;
}

/*
 * Copy the BIOS e820 map into a safe place.
 *
 * Sanity-check it while we're at it..
 *
 * If we're lucky and live on a modern system, the setup code
 * will have given us a memory map that we can use to properly
 * set up memory.  If we aren't, we'll fake a memory map.
 */
static int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
{
      /* Only one memory region (or negative)? Ignore it */
      if (nr_map < 2)
            return -1;

      do {
            unsigned long start = biosmap->addr;
            unsigned long size = biosmap->size;
            unsigned long end = start + size;
            unsigned long type = biosmap->type;

            /* Overflow in 64 bits? Ignore the memory map. */
            if (start > end)
                  return -1;

            add_memory_region(start, size, type);
      } while (biosmap++,--nr_map);
      return 0;
}

void early_panic(char *msg)
{
      early_printk(msg);
      panic(msg);
}

void __init setup_memory_region(void)
{
      /*
       * Try to copy the BIOS-supplied E820-map.
       *
       * Otherwise fake a memory map; one section from 0k->640k,
       * the next section from 1mb->appropriate_mem_k
       */
      sanitize_e820_map(boot_params.e820_map, &boot_params.e820_entries);
      if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0)
            early_panic("Cannot find a valid memory map");
      printk(KERN_INFO "BIOS-provided physical RAM map:\n");
      e820_print_map("BIOS-e820");
}

static int __init parse_memopt(char *p)
{
      if (!p)
            return -EINVAL;
      end_user_pfn = memparse(p, &p);
      end_user_pfn >>= PAGE_SHIFT;  
      return 0;
} 
early_param("mem", parse_memopt);

static int userdef __initdata;

static int __init parse_memmap_opt(char *p)
{
      char *oldp;
      unsigned long long start_at, mem_size;

      if (!strcmp(p, "exactmap")) {
#ifdef CONFIG_CRASH_DUMP
            /* If we are doing a crash dump, we
             * still need to know the real mem
             * size before original memory map is
             * reset.
             */
            e820_register_active_regions(0, 0, -1UL);
            saved_max_pfn = e820_end_of_ram();
            remove_all_active_ranges();
#endif
            end_pfn_map = 0;
            e820.nr_map = 0;
            userdef = 1;
            return 0;
      }

      oldp = p;
      mem_size = memparse(p, &p);
      if (p == oldp)
            return -EINVAL;
      if (*p == '@') {
            start_at = memparse(p+1, &p);
            add_memory_region(start_at, mem_size, E820_RAM);
      } else if (*p == '#') {
            start_at = memparse(p+1, &p);
            add_memory_region(start_at, mem_size, E820_ACPI);
      } else if (*p == '$') {
            start_at = memparse(p+1, &p);
            add_memory_region(start_at, mem_size, E820_RESERVED);
      } else {
            end_user_pfn = (mem_size >> PAGE_SHIFT);
      }
      return *p == '\0' ? 0 : -EINVAL;
}
early_param("memmap", parse_memmap_opt);

void __init finish_e820_parsing(void)
{
      if (userdef) {
            printk(KERN_INFO "user-defined physical RAM map:\n");
            e820_print_map("user");
      }
}

unsigned long pci_mem_start = 0xaeedbabe;
EXPORT_SYMBOL(pci_mem_start);

/*
 * Search for the biggest gap in the low 32 bits of the e820
 * memory space.  We pass this space to PCI to assign MMIO resources
 * for hotplug or unconfigured devices in.
 * Hopefully the BIOS let enough space left.
 */
__init void e820_setup_gap(void)
{
      unsigned long gapstart, gapsize, round;
      unsigned long last;
      int i;
      int found = 0;

      last = 0x100000000ull;
      gapstart = 0x10000000;
      gapsize = 0x400000;
      i = e820.nr_map;
      while (--i >= 0) {
            unsigned long long start = e820.map[i].addr;
            unsigned long long end = start + e820.map[i].size;

            /*
             * Since "last" is at most 4GB, we know we'll
             * fit in 32 bits if this condition is true
             */
            if (last > end) {
                  unsigned long gap = last - end;

                  if (gap > gapsize) {
                        gapsize = gap;
                        gapstart = end;
                        found = 1;
                  }
            }
            if (start < last)
                  last = start;
      }

      if (!found) {
            gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
            printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
                   KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
      }

      /*
       * See how much we want to round up: start off with
       * rounding to the next 1MB area.
       */
      round = 0x100000;
      while ((gapsize >> 4) > round)
            round += round;
      /* Fun with two's complement */
      pci_mem_start = (gapstart + round) & -round;

      printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
            pci_mem_start, gapstart, gapsize);
}

int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
{
      int i;

      if (slot < 0 || slot >= e820.nr_map)
            return -1;
      for (i = slot; i < e820.nr_map; i++) {
            if (e820.map[i].type != E820_RAM)
                  continue;
            break;
      }
      if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
            return -1;
      *addr = e820.map[i].addr;
      *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
            max_pfn << PAGE_SHIFT) - *addr;
      return i + 1;
}

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