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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Low level x86 E820 memory map handling functions.
  *
  * The firmware and bootloader passes us the "E820 table", which is the primary
  * physical memory layout description available about x86 systems.
  *
  * The kernel takes the E820 memory layout and optionally modifies it with
  * quirks and other tweaks, and feeds that into the generic Linux memory
  * allocation code routines via a platform independent interface (memblock, etc.).
  */
 #include <linux/crash_dump.h>
 #include <linux/memblock.h>
 #include <linux/suspend.h>
 #include <linux/acpi.h>
 #include <linux/firmware-map.h>
 #include <linux/sort.h>
 #include <linux/memory_hotplug.h>
 
 #include <asm/e820/api.h>
 #include <asm/setup.h>
 
 /*
  * We organize the E820 table into three main data structures:
  *
  * - 'e820_table_firmware': the original firmware version passed to us by the
  *   bootloader - not modified by the kernel. It is composed of two parts:
  *   the first 128 E820 memory entries in boot_params.e820_table and the remaining
  *   (if any) entries of the SETUP_E820_EXT nodes. We use this to:
  *
  *       - inform the user about the firmware's notion of memory layout
  *         via /sys/firmware/memmap
  *
  *       - the hibernation code uses it to generate a kernel-independent CRC32
  *         checksum of the physical memory layout of a system.
  *
  * - 'e820_table_kexec': a slightly modified (by the kernel) firmware version
  *   passed to us by the bootloader - the major difference between
  *   e820_table_firmware[] and this one is that, the latter marks the setup_data
  *   list created by the EFI boot stub as reserved, so that kexec can reuse the
  *   setup_data information in the second kernel. Besides, e820_table_kexec[]
  *   might also be modified by the kexec itself to fake a mptable.
  *   We use this to:
  *
  *       - kexec, which is a bootloader in disguise, uses the original E820
  *         layout to pass to the kexec-ed kernel. This way the original kernel
  *         can have a restricted E820 map while the kexec()-ed kexec-kernel
  *         can have access to full memory - etc.
  *
  * - 'e820_table': this is the main E820 table that is massaged by the
  *   low level x86 platform code, or modified by boot parameters, before
  *   passed on to higher level MM layers.
  *
  * Once the E820 map has been converted to the standard Linux memory layout
  * information its role stops - modifying it has no effect and does not get
  * re-propagated. So itsmain role is a temporary bootstrap storage of firmware
  * specific memory layout data during early bootup.
  */
 static struct e820_table e820_table_init        __initdata;
 static struct e820_table e820_table_kexec_init      __initdata;
 static struct e820_table e820_table_firmware_init   __initdata;
 
 struct e820_table *e820_table __refdata         = &e820_table_init;
 struct e820_table *e820_table_kexec __refdata       = &e820_table_kexec_init;
 struct e820_table *e820_table_firmware __refdata    = &e820_table_firmware_init;
 
 /* For PCI or other memory-mapped resources */
 unsigned long pci_mem_start = 0xaeedbabe;
 #ifdef CONFIG_PCI
 EXPORT_SYMBOL(pci_mem_start);
 #endif
 
 /*
  * This function checks if any part of the range <start,end> is mapped
  * with type.
  */
 static bool _e820__mapped_any(struct e820_table *table,
                   u64 start, u64 end, enum e820_type type)
 {
     int i;
 
     for (i = 0; i < table->nr_entries; i++) {
         struct e820_entry *entry = &table->entries[i];
 
         if (type && entry->type != type)
             continue;
         if (entry->addr >= end || entry->addr + entry->size <= start)
             continue;
         return true;
     }
     return false;
 }
 
 bool e820__mapped_raw_any(u64 start, u64 end, enum e820_type type)
 {
     return _e820__mapped_any(e820_table_firmware, start, end, type);
 }
 EXPORT_SYMBOL_GPL(e820__mapped_raw_any);
 
 bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
 {
     return _e820__mapped_any(e820_table, start, end, type);
 }
 EXPORT_SYMBOL_GPL(e820__mapped_any);
 
 /*
  * This function checks if the entire <start,end> range is mapped with 'type'.
  *
  * Note: this function only works correctly once the E820 table is sorted and
  * not-overlapping (at least for the range specified), which is the case normally.
  */
 static struct e820_entry *__e820__mapped_all(u64 start, u64 end,
                          enum e820_type type)
 {
     int i;
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = &e820_table->entries[i];
 
         if (type && entry->type != type)
             continue;
 
         /* Is the region (part) in overlap with the current region? */
         if (entry->addr >= end || entry->addr + entry->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 (entry->addr <= start)
             start = entry->addr + entry->size;
 
         /*
          * If 'start' is now at or beyond 'end', we're done, full
          * coverage of the desired range exists:
          */
         if (start >= end)
             return entry;
     }
 
     return NULL;
 }
 
 /*
  * This function checks if the entire range <start,end> is mapped with type.
  */
 bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
 {
     return __e820__mapped_all(start, end, type);
 }
 
 /*
  * This function returns the type associated with the range <start,end>.
  */
 int e820__get_entry_type(u64 start, u64 end)
 {
     struct e820_entry *entry = __e820__mapped_all(start, end, 0);
 
     return entry ? entry->type : -EINVAL;
 }
 
 /*
  * Add a memory region to the kernel E820 map.
  */
 static void __init __e820__range_add(struct e820_table *table, u64 start, u64 size, enum e820_type type)
 {
     int x = table->nr_entries;
 
     if (x >= ARRAY_SIZE(table->entries)) {
         pr_err("too many entries; ignoring [mem %#010llx-%#010llx]\n",
                start, start + size - 1);
         return;
     }
 
     table->entries[x].addr = start;
     table->entries[x].size = size;
     table->entries[x].type = type;
     table->nr_entries++;
 }
 
 void __init e820__range_add(u64 start, u64 size, enum e820_type type)
 {
     __e820__range_add(e820_table, start, size, type);
 }
 
 static void __init e820_print_type(enum e820_type type)
 {
     switch (type) {
     case E820_TYPE_RAM:     /* Fall through: */
     case E820_TYPE_RESERVED_KERN:   pr_cont("usable");          break;
     case E820_TYPE_RESERVED:    pr_cont("reserved");            break;
     case E820_TYPE_SOFT_RESERVED:   pr_cont("soft reserved");       break;
     case E820_TYPE_ACPI:        pr_cont("ACPI data");           break;
     case E820_TYPE_NVS:     pr_cont("ACPI NVS");            break;
     case E820_TYPE_UNUSABLE:    pr_cont("unusable");            break;
     case E820_TYPE_PMEM:        /* Fall through: */
     case E820_TYPE_PRAM:        pr_cont("persistent (type %u)", type);  break;
     default:            pr_cont("type %u", type);       break;
     }
 }
 
 void __init e820__print_table(char *who)
 {
     int i;
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         pr_info("%s: [mem %#018Lx-%#018Lx] ",
             who,
             e820_table->entries[i].addr,
             e820_table->entries[i].addr + e820_table->entries[i].size - 1);
 
         e820_print_type(e820_table->entries[i].type);
         pr_cont("\n");
     }
 }
 
 /*
  * Sanitize an E820 map.
  *
  * Some E820 layouts include overlapping entries. The following
  * replaces the original E820 map with a new one, removing overlaps,
  * and resolving conflicting memory types in favor of highest
  * numbered type.
  *
  * The input parameter 'entries' points to an array of 'struct
  * e820_entry' which on entry has elements in the range [0, *nr_entries)
  * valid, and which has space for up to max_nr_entries entries.
  * On return, the resulting sanitized E820 map entries will be in
  * overwritten in the same location, starting at 'entries'.
  *
  * The integer pointed to by nr_entries must be valid on entry (the
  * current number of valid entries located at 'entries'). If the
  * sanitizing succeeds the *nr_entries will be updated with the new
  * number of valid entries (something no more than max_nr_entries).
  *
  * The return value from e820__update_table() is zero if it
  * successfully 'sanitized' the map entries passed in, and is -1
  * if it did nothing, which can happen if either of (1) it was
  * only passed one map entry, or (2) any of the input map entries
  * were invalid (start + size < start, meaning that the size was
  * so big the described memory range wrapped around through zero.)
  *
  *  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_
  */
 struct change_member {
     /* Pointer to the original entry: */
     struct e820_entry   *entry;
     /* Address for this change point: */
     unsigned long long  addr;
 };
 
 static struct change_member change_point_list[2*E820_MAX_ENTRIES]   __initdata;
 static struct change_member *change_point[2*E820_MAX_ENTRIES]   __initdata;
 static struct e820_entry    *overlap_list[E820_MAX_ENTRIES]     __initdata;
 static struct e820_entry    new_entries[E820_MAX_ENTRIES]       __initdata;
 
 static int __init cpcompare(const void *a, const void *b)
 {
     struct change_member * const *app = a, * const *bpp = b;
     const struct change_member *ap = *app, *bp = *bpp;
 
     /*
      * Inputs are pointers to two elements of change_point[].  If their
      * addresses are not equal, their difference dominates.  If the addresses
      * are equal, then consider one that represents the end of its region
      * to be greater than one that does not.
      */
     if (ap->addr != bp->addr)
         return ap->addr > bp->addr ? 1 : -1;
 
     return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
 }
 
 static bool e820_nomerge(enum e820_type type)
 {
     /*
      * These types may indicate distinct platform ranges aligned to
      * numa node, protection domain, performance domain, or other
      * boundaries. Do not merge them.
      */
     if (type == E820_TYPE_PRAM)
         return true;
     if (type == E820_TYPE_SOFT_RESERVED)
         return true;
     return false;
 }
 
 int __init e820__update_table(struct e820_table *table)
 {
     struct e820_entry *entries = table->entries;
     u32 max_nr_entries = ARRAY_SIZE(table->entries);
     enum e820_type current_type, last_type;
     unsigned long long last_addr;
     u32 new_nr_entries, overlap_entries;
     u32 i, chg_idx, chg_nr;
 
     /* If there's only one memory region, don't bother: */
     if (table->nr_entries < 2)
         return -1;
 
     BUG_ON(table->nr_entries > max_nr_entries);
 
     /* Bail out if we find any unreasonable addresses in the map: */
     for (i = 0; i < table->nr_entries; i++) {
         if (entries[i].addr + entries[i].size < entries[i].addr)
             return -1;
     }
 
     /* Create pointers for initial change-point information (for sorting): */
     for (i = 0; i < 2 * table->nr_entries; i++)
         change_point[i] = &change_point_list[i];
 
     /*
      * Record all known change-points (starting and ending addresses),
      * omitting empty memory regions:
      */
     chg_idx = 0;
     for (i = 0; i < table->nr_entries; i++) {
         if (entries[i].size != 0) {
             change_point[chg_idx]->addr = entries[i].addr;
             change_point[chg_idx++]->entry  = &entries[i];
             change_point[chg_idx]->addr = entries[i].addr + entries[i].size;
             change_point[chg_idx++]->entry  = &entries[i];
         }
     }
     chg_nr = chg_idx;
 
     /* Sort change-point list by memory addresses (low -> high): */
     sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL);
 
     /* Create a new memory map, removing overlaps: */
     overlap_entries = 0;     /* Number of entries in the overlap table */
     new_nr_entries = 0;  /* Index for creating new 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 effect on the new map: */
     for (chg_idx = 0; chg_idx < chg_nr; chg_idx++) {
         /* Keep track of all overlapping entries */
         if (change_point[chg_idx]->addr == change_point[chg_idx]->entry->addr) {
             /* Add map entry to overlap list (> 1 entry implies an overlap) */
             overlap_list[overlap_entries++] = change_point[chg_idx]->entry;
         } else {
             /* Remove entry from list (order independent, so swap with last): */
             for (i = 0; i < overlap_entries; i++) {
                 if (overlap_list[i] == change_point[chg_idx]->entry)
                     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 map based on this information: */
         if (current_type != last_type || e820_nomerge(current_type)) {
             if (last_type != 0)  {
                 new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
                 /* Move forward only if the new size was non-zero: */
                 if (new_entries[new_nr_entries].size != 0)
                     /* No more space left for new entries? */
                     if (++new_nr_entries >= max_nr_entries)
                         break;
             }
             if (current_type != 0)  {
                 new_entries[new_nr_entries].addr = change_point[chg_idx]->addr;
                 new_entries[new_nr_entries].type = current_type;
                 last_addr = change_point[chg_idx]->addr;
             }
             last_type = current_type;
         }
     }
 
     /* Copy the new entries into the original location: */
     memcpy(entries, new_entries, new_nr_entries*sizeof(*entries));
     table->nr_entries = new_nr_entries;
 
     return 0;
 }
 
 static int __init __append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
 {
     struct boot_e820_entry *entry = entries;
 
     while (nr_entries) {
         u64 start = entry->addr;
         u64 size = entry->size;
         u64 end = start + size - 1;
         u32 type = entry->type;
 
         /* Ignore the entry on 64-bit overflow: */
         if (start > end && likely(size))
             return -1;
 
         e820__range_add(start, size, type);
 
         entry++;
         nr_entries--;
     }
     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 append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
 {
     /* Only one memory region (or negative)? Ignore it */
     if (nr_entries < 2)
         return -1;
 
     return __append_e820_table(entries, nr_entries);
 }
 
 static u64 __init
 __e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
 {
     u64 end;
     unsigned int i;
     u64 real_updated_size = 0;
 
     BUG_ON(old_type == new_type);
 
     if (size > (ULLONG_MAX - start))
         size = ULLONG_MAX - start;
 
     end = start + size;
     printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx] ", start, end - 1);
     e820_print_type(old_type);
     pr_cont(" ==> ");
     e820_print_type(new_type);
     pr_cont("\n");
 
     for (i = 0; i < table->nr_entries; i++) {
         struct e820_entry *entry = &table->entries[i];
         u64 final_start, final_end;
         u64 entry_end;
 
         if (entry->type != old_type)
             continue;
 
         entry_end = entry->addr + entry->size;
 
         /* Completely covered by new range? */
         if (entry->addr >= start && entry_end <= end) {
             entry->type = new_type;
             real_updated_size += entry->size;
             continue;
         }
 
         /* New range is completely covered? */
         if (entry->addr < start && entry_end > end) {
             __e820__range_add(table, start, size, new_type);
             __e820__range_add(table, end, entry_end - end, entry->type);
             entry->size = start - entry->addr;
             real_updated_size += size;
             continue;
         }
 
         /* Partially covered: */
         final_start = max(start, entry->addr);
         final_end = min(end, entry_end);
         if (final_start >= final_end)
             continue;
 
         __e820__range_add(table, final_start, final_end - final_start, new_type);
 
         real_updated_size += final_end - final_start;
 
         /*
          * Left range could be head or tail, so need to update
          * its size first:
          */
         entry->size -= final_end - final_start;
         if (entry->addr < final_start)
             continue;
 
         entry->addr = final_end;
     }
     return real_updated_size;
 }
 
 u64 __init e820__range_update(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
 {
     return __e820__range_update(e820_table, start, size, old_type, new_type);
 }
 
 static u64 __init e820__range_update_kexec(u64 start, u64 size, enum e820_type old_type, enum e820_type  new_type)
 {
     return __e820__range_update(e820_table_kexec, start, size, old_type, new_type);
 }
 
 /* Remove a range of memory from the E820 table: */
 u64 __init e820__range_remove(u64 start, u64 size, enum e820_type old_type, bool check_type)
 {
     int i;
     u64 end;
     u64 real_removed_size = 0;
 
     if (size > (ULLONG_MAX - start))
         size = ULLONG_MAX - start;
 
     end = start + size;
     printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx] ", start, end - 1);
     if (check_type)
         e820_print_type(old_type);
     pr_cont("\n");
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = &e820_table->entries[i];
         u64 final_start, final_end;
         u64 entry_end;
 
         if (check_type && entry->type != old_type)
             continue;
 
         entry_end = entry->addr + entry->size;
 
         /* Completely covered? */
         if (entry->addr >= start && entry_end <= end) {
             real_removed_size += entry->size;
             memset(entry, 0, sizeof(*entry));
             continue;
         }
 
         /* Is the new range completely covered? */
         if (entry->addr < start && entry_end > end) {
             e820__range_add(end, entry_end - end, entry->type);
             entry->size = start - entry->addr;
             real_removed_size += size;
             continue;
         }
 
         /* Partially covered: */
         final_start = max(start, entry->addr);
         final_end = min(end, entry_end);
         if (final_start >= final_end)
             continue;
 
         real_removed_size += final_end - final_start;
 
         /*
          * Left range could be head or tail, so need to update
          * the size first:
          */
         entry->size -= final_end - final_start;
         if (entry->addr < final_start)
             continue;
 
         entry->addr = final_end;
     }
     return real_removed_size;
 }
 
 void __init e820__update_table_print(void)
 {
     if (e820__update_table(e820_table))
         return;
 
     pr_info("modified physical RAM map:\n");
     e820__print_table("modified");
 }
 
 static void __init e820__update_table_kexec(void)
 {
     e820__update_table(e820_table_kexec);
 }
 
 #define MAX_GAP_END 0x100000000ull
 
 /*
  * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
  */
 static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsize)
 {
     unsigned long long last = MAX_GAP_END;
     int i = e820_table->nr_entries;
     int found = 0;
 
     while (--i >= 0) {
         unsigned long long start = e820_table->entries[i].addr;
         unsigned long long end = start + e820_table->entries[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;
     }
     return found;
 }
 
 /*
  * Search for the biggest gap in the low 32 bits of the E820
  * memory space. We pass this space to the PCI subsystem, so
  * that it can assign MMIO resources for hotplug or
  * unconfigured devices in.
  *
  * Hopefully the BIOS let enough space left.
  */
 __init void e820__setup_pci_gap(void)
 {
     unsigned long gapstart, gapsize;
     int found;
 
     gapsize = 0x400000;
     found  = e820_search_gap(&gapstart, &gapsize);
 
     if (!found) {
 #ifdef CONFIG_X86_64
         gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
         pr_err("Cannot find an available gap in the 32-bit address range\n");
         pr_err("PCI devices with unassigned 32-bit BARs may not work!\n");
 #else
         gapstart = 0x10000000;
 #endif
     }
 
     /*
      * e820__reserve_resources_late() protects stolen RAM already:
      */
     pci_mem_start = gapstart;
 
     pr_info("[mem %#010lx-%#010lx] available for PCI devices\n",
         gapstart, gapstart + gapsize - 1);
 }
 
 /*
  * Called late during init, in free_initmem().
  *
  * Initial e820_table and e820_table_kexec are largish __initdata arrays.
  *
  * Copy them to a (usually much smaller) dynamically allocated area that is
  * sized precisely after the number of e820 entries.
  *
  * This is done after we've performed all the fixes and tweaks to the tables.
  * All functions which modify them are __init functions, which won't exist
  * after free_initmem().
  */
 __init void e820__reallocate_tables(void)
 {
     struct e820_table *n;
     int size;
 
     size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table->nr_entries;
     n = kmemdup(e820_table, size, GFP_KERNEL);
     BUG_ON(!n);
     e820_table = n;
 
     size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_kexec->nr_entries;
     n = kmemdup(e820_table_kexec, size, GFP_KERNEL);
     BUG_ON(!n);
     e820_table_kexec = n;
 
     size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_firmware->nr_entries;
     n = kmemdup(e820_table_firmware, size, GFP_KERNEL);
     BUG_ON(!n);
     e820_table_firmware = n;
 }
 
 /*
  * Because of the small fixed size of struct boot_params, only the first
  * 128 E820 memory entries are passed to the kernel via boot_params.e820_table,
  * the remaining (if any) entries are passed via the SETUP_E820_EXT node of
  * struct setup_data, which is parsed here.
  */
 void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
 {
     int entries;
     struct boot_e820_entry *extmap;
     struct setup_data *sdata;
 
     sdata = early_memremap(phys_addr, data_len);
     entries = sdata->len / sizeof(*extmap);
     extmap = (struct boot_e820_entry *)(sdata->data);
 
     __append_e820_table(extmap, entries);
     e820__update_table(e820_table);
 
     memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
     memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
 
     early_memunmap(sdata, data_len);
     pr_info("extended physical RAM map:\n");
     e820__print_table("extended");
 }
 
 /*
  * Find the ranges of physical addresses that do not correspond to
  * E820 RAM areas and register the corresponding pages as 'nosave' for
  * hibernation (32-bit) or software suspend and suspend to RAM (64-bit).
  *
  * This function requires the E820 map to be sorted and without any
  * overlapping entries.
  */
 void __init e820__register_nosave_regions(unsigned long limit_pfn)
 {
     int i;
     unsigned long pfn = 0;
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = &e820_table->entries[i];
 
         if (pfn < PFN_UP(entry->addr))
             register_nosave_region(pfn, PFN_UP(entry->addr));
 
         pfn = PFN_DOWN(entry->addr + entry->size);
 
         if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
             register_nosave_region(PFN_UP(entry->addr), pfn);
 
         if (pfn >= limit_pfn)
             break;
     }
 }
 
 #ifdef CONFIG_ACPI
 /*
  * Register ACPI NVS memory regions, so that we can save/restore them during
  * hibernation and the subsequent resume:
  */
 static int __init e820__register_nvs_regions(void)
 {
     int i;
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = &e820_table->entries[i];
 
         if (entry->type == E820_TYPE_NVS)
             acpi_nvs_register(entry->addr, entry->size);
     }
 
     return 0;
 }
 core_initcall(e820__register_nvs_regions);
 #endif
 
 /*
  * Allocate the requested number of bytes with the requested alignment
  * and return (the physical address) to the caller. Also register this
  * range in the 'kexec' E820 table as a reserved range.
  *
  * This allows kexec to fake a new mptable, as if it came from the real
  * system.
  */
 u64 __init e820__memblock_alloc_reserved(u64 size, u64 align)
 {
     u64 addr;
 
     addr = memblock_phys_alloc(size, align);
     if (addr) {
         e820__range_update_kexec(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
         pr_info("update e820_table_kexec for e820__memblock_alloc_reserved()\n");
         e820__update_table_kexec();
     }
 
     return addr;
 }
 
 #ifdef CONFIG_X86_32
 # ifdef CONFIG_X86_PAE
 #  define MAX_ARCH_PFN      (1ULL<<(36-PAGE_SHIFT))
 # else
 #  define MAX_ARCH_PFN      (1ULL<<(32-PAGE_SHIFT))
 # endif
 #else /* CONFIG_X86_32 */
 # define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
 #endif
 
 /*
  * Find the highest page frame number we have available
  */
 static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type type)
 {
     int i;
     unsigned long last_pfn = 0;
     unsigned long max_arch_pfn = MAX_ARCH_PFN;
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = &e820_table->entries[i];
         unsigned long start_pfn;
         unsigned long end_pfn;
 
         if (entry->type != type)
             continue;
 
         start_pfn = entry->addr >> PAGE_SHIFT;
         end_pfn = (entry->addr + entry->size) >> PAGE_SHIFT;
 
         if (start_pfn >= limit_pfn)
             continue;
         if (end_pfn > limit_pfn) {
             last_pfn = limit_pfn;
             break;
         }
         if (end_pfn > last_pfn)
             last_pfn = end_pfn;
     }
 
     if (last_pfn > max_arch_pfn)
         last_pfn = max_arch_pfn;
 
     pr_info("last_pfn = %#lx max_arch_pfn = %#lx\n",
         last_pfn, max_arch_pfn);
     return last_pfn;
 }
 
 unsigned long __init e820__end_of_ram_pfn(void)
 {
     return e820_end_pfn(MAX_ARCH_PFN, E820_TYPE_RAM);
 }
 
 unsigned long __init e820__end_of_low_ram_pfn(void)
 {
     return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_TYPE_RAM);
 }
 
 static void __init early_panic(char *msg)
 {
     early_printk(msg);
     panic(msg);
 }
 
 static int userdef __initdata;
 
 /* The "mem=nopentium" boot option disables 4MB page tables on 32-bit kernels: */
 static int __init parse_memopt(char *p)
 {
     u64 mem_size;
 
     if (!p)
         return -EINVAL;
 
     if (!strcmp(p, "nopentium")) {
 #ifdef CONFIG_X86_32
         setup_clear_cpu_cap(X86_FEATURE_PSE);
         return 0;
 #else
         pr_warn("mem=nopentium ignored! (only supported on x86_32)\n");
         return -EINVAL;
 #endif
     }
 
     userdef = 1;
     mem_size = memparse(p, &p);
 
     /* Don't remove all memory when getting "mem={invalid}" parameter: */
     if (mem_size == 0)
         return -EINVAL;
 
     e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
 
 #ifdef CONFIG_MEMORY_HOTPLUG
     max_mem_size = mem_size;
 #endif
 
     return 0;
 }
 early_param("mem", parse_memopt);
 
 static int __init parse_memmap_one(char *p)
 {
     char *oldp;
     u64 start_at, mem_size;
 
     if (!p)
         return -EINVAL;
 
     if (!strncmp(p, "exactmap", 8)) {
         e820_table->nr_entries = 0;
         userdef = 1;
         return 0;
     }
 
     oldp = p;
     mem_size = memparse(p, &p);
     if (p == oldp)
         return -EINVAL;
 
     userdef = 1;
     if (*p == '@') {
         start_at = memparse(p+1, &p);
         e820__range_add(start_at, mem_size, E820_TYPE_RAM);
     } else if (*p == '#') {
         start_at = memparse(p+1, &p);
         e820__range_add(start_at, mem_size, E820_TYPE_ACPI);
     } else if (*p == '$') {
         start_at = memparse(p+1, &p);
         e820__range_add(start_at, mem_size, E820_TYPE_RESERVED);
     } else if (*p == '!') {
         start_at = memparse(p+1, &p);
         e820__range_add(start_at, mem_size, E820_TYPE_PRAM);
     } else if (*p == '%') {
         enum e820_type from = 0, to = 0;
 
         start_at = memparse(p + 1, &p);
         if (*p == '-')
             from = simple_strtoull(p + 1, &p, 0);
         if (*p == '+')
             to = simple_strtoull(p + 1, &p, 0);
         if (*p != '\0')
             return -EINVAL;
         if (from && to)
             e820__range_update(start_at, mem_size, from, to);
         else if (to)
             e820__range_add(start_at, mem_size, to);
         else if (from)
             e820__range_remove(start_at, mem_size, from, 1);
         else
             e820__range_remove(start_at, mem_size, 0, 0);
     } else {
         e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
     }
 
     return *p == '\0' ? 0 : -EINVAL;
 }
 
 static int __init parse_memmap_opt(char *str)
 {
     while (str) {
         char *k = strchr(str, ',');
 
         if (k)
             *k++ = 0;
 
         parse_memmap_one(str);
         str = k;
     }
 
     return 0;
 }
 early_param("memmap", parse_memmap_opt);
 
 /*
  * Reserve all entries from the bootloader's extensible data nodes list,
  * because if present we are going to use it later on to fetch e820
  * entries from it:
  */
 void __init e820__reserve_setup_data(void)
 {
     struct setup_indirect *indirect;
     struct setup_data *data;
     u64 pa_data, pa_next;
     u32 len;
 
     pa_data = boot_params.hdr.setup_data;
     if (!pa_data)
         return;
 
     while (pa_data) {
         data = early_memremap(pa_data, sizeof(*data));
         if (!data) {
             pr_warn("e820: failed to memremap setup_data entry\n");
             return;
         }
 
         len = sizeof(*data);
         pa_next = data->next;
 
         e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
 
         /*
          * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
          * to be reserved.
          */
         if (data->type != SETUP_EFI && data->type != SETUP_IMA)
             e820__range_update_kexec(pa_data,
                          sizeof(*data) + data->len,
                          E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
 
         if (data->type == SETUP_INDIRECT) {
             len += data->len;
             early_memunmap(data, sizeof(*data));
             data = early_memremap(pa_data, len);
             if (!data) {
                 pr_warn("e820: failed to memremap indirect setup_data\n");
                 return;
             }
 
             indirect = (struct setup_indirect *)data->data;
 
             if (indirect->type != SETUP_INDIRECT) {
                 e820__range_update(indirect->addr, indirect->len,
                            E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
                 e820__range_update_kexec(indirect->addr, indirect->len,
                              E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
             }
         }
 
         pa_data = pa_next;
         early_memunmap(data, len);
     }
 
     e820__update_table(e820_table);
     e820__update_table(e820_table_kexec);
 
     pr_info("extended physical RAM map:\n");
     e820__print_table("reserve setup_data");
 }
 
 /*
  * Called after parse_early_param(), after early parameters (such as mem=)
  * have been processed, in which case we already have an E820 table filled in
  * via the parameter callback function(s), but it's not sorted and printed yet:
  */
 void __init e820__finish_early_params(void)
 {
     if (userdef) {
         if (e820__update_table(e820_table) < 0)
             early_panic("Invalid user supplied memory map");
 
         pr_info("user-defined physical RAM map:\n");
         e820__print_table("user");
     }
 }
 
 static const char *__init e820_type_to_string(struct e820_entry *entry)
 {
     switch (entry->type) {
     case E820_TYPE_RESERVED_KERN:   /* Fall-through: */
     case E820_TYPE_RAM:     return "System RAM";
     case E820_TYPE_ACPI:        return "ACPI Tables";
     case E820_TYPE_NVS:     return "ACPI Non-volatile Storage";
     case E820_TYPE_UNUSABLE:    return "Unusable memory";
     case E820_TYPE_PRAM:        return "Persistent Memory (legacy)";
     case E820_TYPE_PMEM:        return "Persistent Memory";
     case E820_TYPE_RESERVED:    return "Reserved";
     case E820_TYPE_SOFT_RESERVED:   return "Soft Reserved";
     default:            return "Unknown E820 type";
     }
 }
 
 static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)
 {
     switch (entry->type) {
     case E820_TYPE_RESERVED_KERN:   /* Fall-through: */
     case E820_TYPE_RAM:     return IORESOURCE_SYSTEM_RAM;
     case E820_TYPE_ACPI:        /* Fall-through: */
     case E820_TYPE_NVS:     /* Fall-through: */
     case E820_TYPE_UNUSABLE:    /* Fall-through: */
     case E820_TYPE_PRAM:        /* Fall-through: */
     case E820_TYPE_PMEM:        /* Fall-through: */
     case E820_TYPE_RESERVED:    /* Fall-through: */
     case E820_TYPE_SOFT_RESERVED:   /* Fall-through: */
     default:            return IORESOURCE_MEM;
     }
 }
 
 static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry)
 {
     switch (entry->type) {
     case E820_TYPE_ACPI:        return IORES_DESC_ACPI_TABLES;
     case E820_TYPE_NVS:     return IORES_DESC_ACPI_NV_STORAGE;
     case E820_TYPE_PMEM:        return IORES_DESC_PERSISTENT_MEMORY;
     case E820_TYPE_PRAM:        return IORES_DESC_PERSISTENT_MEMORY_LEGACY;
     case E820_TYPE_RESERVED:    return IORES_DESC_RESERVED;
     case E820_TYPE_SOFT_RESERVED:   return IORES_DESC_SOFT_RESERVED;
     case E820_TYPE_RESERVED_KERN:   /* Fall-through: */
     case E820_TYPE_RAM:     /* Fall-through: */
     case E820_TYPE_UNUSABLE:    /* Fall-through: */
     default:            return IORES_DESC_NONE;
     }
 }
 
 static bool __init do_mark_busy(enum e820_type type, struct resource *res)
 {
     /* this is the legacy bios/dos rom-shadow + mmio region */
     if (res->start < (1ULL<<20))
         return true;
 
     /*
      * Treat persistent memory and other special memory ranges like
      * device memory, i.e. reserve it for exclusive use of a driver
      */
     switch (type) {
     case E820_TYPE_RESERVED:
     case E820_TYPE_SOFT_RESERVED:
     case E820_TYPE_PRAM:
     case E820_TYPE_PMEM:
         return false;
     case E820_TYPE_RESERVED_KERN:
     case E820_TYPE_RAM:
     case E820_TYPE_ACPI:
     case E820_TYPE_NVS:
     case E820_TYPE_UNUSABLE:
     default:
         return true;
     }
 }
 
 /*
  * Mark E820 reserved areas as busy for the resource manager:
  */
 
 static struct resource __initdata *e820_res;
 
 void __init e820__reserve_resources(void)
 {
     int i;
     struct resource *res;
     u64 end;
 
     res = memblock_alloc(sizeof(*res) * e820_table->nr_entries,
                  SMP_CACHE_BYTES);
     if (!res)
         panic("%s: Failed to allocate %zu bytes\n", __func__,
               sizeof(*res) * e820_table->nr_entries);
     e820_res = res;
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = e820_table->entries + i;
 
         end = entry->addr + entry->size - 1;
         if (end != (resource_size_t)end) {
             res++;
             continue;
         }
         res->start = entry->addr;
         res->end   = end;
         res->name  = e820_type_to_string(entry);
         res->flags = e820_type_to_iomem_type(entry);
         res->desc  = e820_type_to_iores_desc(entry);
 
         /*
          * Don't register the region that could be conflicted with
          * PCI device BAR resources and insert them later in
          * pcibios_resource_survey():
          */
         if (do_mark_busy(entry->type, res)) {
             res->flags |= IORESOURCE_BUSY;
             insert_resource(&iomem_resource, res);
         }
         res++;
     }
 
     /* Expose the bootloader-provided memory layout to the sysfs. */
     for (i = 0; i < e820_table_firmware->nr_entries; i++) {
         struct e820_entry *entry = e820_table_firmware->entries + i;
 
         firmware_map_add_early(entry->addr, entry->addr + entry->size, e820_type_to_string(entry));
     }
 }
 
 /*
  * How much should we pad the end of RAM, depending on where it is?
  */
 static unsigned long __init ram_alignment(resource_size_t pos)
 {
     unsigned long mb = pos >> 20;
 
     /* To 64kB in the first megabyte */
     if (!mb)
         return 64*1024;
 
     /* To 1MB in the first 16MB */
     if (mb < 16)
         return 1024*1024;
 
     /* To 64MB for anything above that */
     return 64*1024*1024;
 }
 
 #define MAX_RESOURCE_SIZE ((resource_size_t)-1)
 
 void __init e820__reserve_resources_late(void)
 {
     int i;
     struct resource *res;
 
     res = e820_res;
     for (i = 0; i < e820_table->nr_entries; i++) {
         if (!res->parent && res->end)
             insert_resource_expand_to_fit(&iomem_resource, res);
         res++;
     }
 
     /*
      * Try to bump up RAM regions to reasonable boundaries, to
      * avoid stolen RAM:
      */
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = &e820_table->entries[i];
         u64 start, end;
 
         if (entry->type != E820_TYPE_RAM)
             continue;
 
         start = entry->addr + entry->size;
         end = round_up(start, ram_alignment(start)) - 1;
         if (end > MAX_RESOURCE_SIZE)
             end = MAX_RESOURCE_SIZE;
         if (start >= end)
             continue;
 
         printk(KERN_DEBUG "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n", start, end);
         reserve_region_with_split(&iomem_resource, start, end, "RAM buffer");
     }
 }
 
 /*
  * Pass the firmware (bootloader) E820 map to the kernel and process it:
  */
 char *__init e820__memory_setup_default(void)
 {
     char *who = "BIOS-e820";
 
     /*
      * 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
      */
     if (append_e820_table(boot_params.e820_table, boot_params.e820_entries) < 0) {
         u64 mem_size;
 
         /* Compare results from other methods and take the one that gives more RAM: */
         if (boot_params.alt_mem_k < boot_params.screen_info.ext_mem_k) {
             mem_size = boot_params.screen_info.ext_mem_k;
             who = "BIOS-88";
         } else {
             mem_size = boot_params.alt_mem_k;
             who = "BIOS-e801";
         }
 
         e820_table->nr_entries = 0;
         e820__range_add(0, LOWMEMSIZE(), E820_TYPE_RAM);
         e820__range_add(HIGH_MEMORY, mem_size << 10, E820_TYPE_RAM);
     }
 
     /* We just appended a lot of ranges, sanitize the table: */
     e820__update_table(e820_table);
 
     return who;
 }
 
 /*
  * Calls e820__memory_setup_default() in essence to pick up the firmware/bootloader
  * E820 map - with an optional platform quirk available for virtual platforms
  * to override this method of boot environment processing:
  */
 void __init e820__memory_setup(void)
 {
     char *who;
 
     /* This is a firmware interface ABI - make sure we don't break it: */
     BUILD_BUG_ON(sizeof(struct boot_e820_entry) != 20);
 
     who = x86_init.resources.memory_setup();
 
     memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
     memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
 
     pr_info("BIOS-provided physical RAM map:\n");
     e820__print_table(who);
 }
 
 void __init e820__memblock_setup(void)
 {
     int i;
     u64 end;
 
     /*
      * The bootstrap memblock region count maximum is 128 entries
      * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
      * than that - so allow memblock resizing.
      *
      * This is safe, because this call happens pretty late during x86 setup,
      * so we know about reserved memory regions already. (This is important
      * so that memblock resizing does no stomp over reserved areas.)
      */
     memblock_allow_resize();
 
     for (i = 0; i < e820_table->nr_entries; i++) {
         struct e820_entry *entry = &e820_table->entries[i];
 
         end = entry->addr + entry->size;
         if (end != (resource_size_t)end)
             continue;
 
         if (entry->type == E820_TYPE_SOFT_RESERVED)
             memblock_reserve(entry->addr, entry->size);
 
         if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
             continue;
 
         memblock_add(entry->addr, entry->size);
     }
 
     /* Throw away partial pages: */
     memblock_trim_memory(PAGE_SIZE);
 
     memblock_dump_all();
 }

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