arch/x86/kernel/e820_64.c

   1 /*
   2  * Handle the memory map.
   3  * The functions here do the job until bootmem takes over.
   4  *
   5  *  Getting sanitize_e820_map() in sync with i386 version by applying change:
   6  *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
   7  *     Alex Achenbach <xela@slit.de>, December 2002.
   8  *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   9  *
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/types.h>
  13 #include <linux/init.h>
  14 #include <linux/bootmem.h>
  15 #include <linux/ioport.h>
  16 #include <linux/string.h>
  17 #include <linux/kexec.h>
  18 #include <linux/module.h>
  19 #include <linux/mm.h>
  20 #include <linux/pfn.h>
  21 #include <linux/pci.h>
  22
  23 #include <asm/pgtable.h>
  24 #include <asm/page.h>
  25 #include <asm/e820.h>
  26 #include <asm/proto.h>
  27 #include <asm/setup.h>
  28 #include <asm/sections.h>
  29 #include <asm/kdebug.h>
  30 #include <asm/trampoline.h>
  31
  32 /*
  33  * PFN of last memory page.
  34  */
  35 unsigned long end_pfn;
  36
  37 /*
  38  * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
  39  * The direct mapping extends to max_pfn_mapped, so that we can directly access
  40  * apertures, ACPI and other tables without having to play with fixmaps.
  41  */
  42 unsigned long max_pfn_mapped;
  43
  44 /*
  45  * Last pfn which the user wants to use.
  46  */
  47 static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
  48
  49 /*
  50  * Find the highest page frame number we have available
  51  */
  52 unsigned long __init e820_end_of_ram(void)
  53 {
  54         unsigned long last_pfn;
  55
  56         last_pfn = find_max_pfn_with_active_regions();
  57
  58         if (last_pfn > MAXMEM>>PAGE_SHIFT)
  59                 last_pfn = MAXMEM>>PAGE_SHIFT;
  60         if (last_pfn > end_user_pfn)
  61                 last_pfn = end_user_pfn;
  62
  63         printk(KERN_INFO "last_pfn = %lu\n", last_pfn);
  64         return last_pfn;
  65 }
  66
  67 /*
  68  * Mark e820 reserved areas as busy for the resource manager.
  69  */
  70 void __init e820_reserve_resources(void)
  71 {
  72         int i;
  73         struct resource *res;
  74
  75         res = alloc_bootmem_low(sizeof(struct resource) * e820.nr_map);
  76         for (i = 0; i < e820.nr_map; i++) {
  77                 switch (e820.map[i].type) {
  78                 case E820_RAM:  res->name = "System RAM"; break;
  79                 case E820_ACPI: res->name = "ACPI Tables"; break;
  80                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
  81                 default:        res->name = "reserved";
  82                 }
  83                 res->start = e820.map[i].addr;
  84                 res->end = res->start + e820.map[i].size - 1;
  85                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  86                 insert_resource(&iomem_resource, res);
  87                 res++;
  88         }
  89 }
  90
  91 /*
  92  * Finds an active region in the address range from start_pfn to last_pfn and
  93  * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
  94  */
  95 static int __init e820_find_active_region(const struct e820entry *ei,
  96                                           unsigned long start_pfn,
  97                                           unsigned long last_pfn,
  98                                           unsigned long *ei_startpfn,
  99                                           unsigned long *ei_endpfn)
 100 {
 101         *ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
 102         *ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
 103
 104         /* Skip map entries smaller than a page */
 105         if (*ei_startpfn >= *ei_endpfn)
 106                 return 0;
 107
 108         /* Skip if map is outside the node */
 109         if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
 110                                     *ei_startpfn >= last_pfn)
 111                 return 0;
 112
 113         /* Check for overlaps */
 114         if (*ei_startpfn < start_pfn)
 115                 *ei_startpfn = start_pfn;
 116         if (*ei_endpfn > last_pfn)
 117                 *ei_endpfn = last_pfn;
 118
 119         /* Obey end_user_pfn to save on memmap */
 120         if (*ei_startpfn >= end_user_pfn)
 121                 return 0;
 122         if (*ei_endpfn > end_user_pfn)
 123                 *ei_endpfn = end_user_pfn;
 124
 125         return 1;
 126 }
 127
 128 /* Walk the e820 map and register active regions within a node */
 129 void __init
 130 e820_register_active_regions(int nid, unsigned long start_pfn,
 131                                                         unsigned long last_pfn)
 132 {
 133         unsigned long ei_startpfn;
 134         unsigned long ei_endpfn;
 135         int i;
 136
 137         for (i = 0; i < e820.nr_map; i++)
 138                 if (e820_find_active_region(&e820.map[i],
 139                                             start_pfn, last_pfn,
 140                                             &ei_startpfn, &ei_endpfn))
 141                         add_active_range(nid, ei_startpfn, ei_endpfn);
 142 }
 143
 144 /*
 145  * Find the hole size (in bytes) in the memory range.
 146  * @start: starting address of the memory range to scan
 147  * @end: ending address of the memory range to scan
 148  */
 149 unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
 150 {
 151         unsigned long start_pfn = start >> PAGE_SHIFT;
 152         unsigned long last_pfn = end >> PAGE_SHIFT;
 153         unsigned long ei_startpfn, ei_endpfn, ram = 0;
 154         int i;
 155
 156         for (i = 0; i < e820.nr_map; i++) {
 157                 if (e820_find_active_region(&e820.map[i],
 158                                             start_pfn, last_pfn,
 159                                             &ei_startpfn, &ei_endpfn))
 160                         ram += ei_endpfn - ei_startpfn;
 161         }
 162         return end - start - (ram << PAGE_SHIFT);
 163 }
 164
 165 static void early_panic(char *msg)
 166 {
 167         early_printk(msg);
 168         panic(msg);
 169 }
 170
 171 /* We're not void only for x86 32-bit compat */
 172 char *__init machine_specific_memory_setup(void)
 173 {
 174         char *who = "BIOS-e820";
 175         int new_nr;
 176         /*
 177          * Try to copy the BIOS-supplied E820-map.
 178          *
 179          * Otherwise fake a memory map; one section from 0k->640k,
 180          * the next section from 1mb->appropriate_mem_k
 181          */
 182         new_nr = boot_params.e820_entries;
 183         sanitize_e820_map(boot_params.e820_map,
 184                         ARRAY_SIZE(boot_params.e820_map),
 185                         &new_nr);
 186         boot_params.e820_entries = new_nr;
 187         if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0)
 188                 early_panic("Cannot find a valid memory map");
 189         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 190         e820_print_map(who);
 191
 192         /* In case someone cares... */
 193         return who;
 194 }
 195
 196 static int __init parse_memopt(char *p)
 197 {
 198         if (!p)
 199                 return -EINVAL;
 200         end_user_pfn = memparse(p, &p);
 201         end_user_pfn >>= PAGE_SHIFT;
 202         return 0;
 203 }
 204 early_param("mem", parse_memopt);
 205
 206 static int userdef __initdata;
 207
 208 static int __init parse_memmap_opt(char *p)
 209 {
 210         char *oldp;
 211         unsigned long long start_at, mem_size;
 212
 213         if (!strcmp(p, "exactmap")) {
 214 #ifdef CONFIG_CRASH_DUMP
 215                 /*
 216                  * If we are doing a crash dump, we still need to know
 217                  * the real mem size before original memory map is
 218                  * reset.
 219                  */
 220                 e820_register_active_regions(0, 0, -1UL);
 221                 saved_max_pfn = e820_end_of_ram();
 222                 remove_all_active_ranges();
 223 #endif
 224                 e820.nr_map = 0;
 225                 userdef = 1;
 226                 return 0;
 227         }
 228
 229         oldp = p;
 230         mem_size = memparse(p, &p);
 231         if (p == oldp)
 232                 return -EINVAL;
 233
 234         userdef = 1;
 235         if (*p == '@') {
 236                 start_at = memparse(p+1, &p);
 237                 add_memory_region(start_at, mem_size, E820_RAM);
 238         } else if (*p == '#') {
 239                 start_at = memparse(p+1, &p);
 240                 add_memory_region(start_at, mem_size, E820_ACPI);
 241         } else if (*p == '$') {
 242                 start_at = memparse(p+1, &p);
 243                 add_memory_region(start_at, mem_size, E820_RESERVED);
 244         } else {
 245                 end_user_pfn = (mem_size >> PAGE_SHIFT);
 246         }
 247         return *p == '\0' ? 0 : -EINVAL;
 248 }
 249 early_param("memmap", parse_memmap_opt);
 250
 251 void __init finish_e820_parsing(void)
 252 {
 253         if (userdef) {
 254                 int nr = e820.nr_map;
 255
 256                 if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &nr) < 0)
 257                         early_panic("Invalid user supplied memory map");
 258                 e820.nr_map = nr;
 259
 260                 printk(KERN_INFO "user-defined physical RAM map:\n");
 261                 e820_print_map("user");
 262         }
 263 }
 264
 265 int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
 266 {
 267         int i;
 268
 269         if (slot < 0 || slot >= e820.nr_map)
 270                 return -1;
 271         for (i = slot; i < e820.nr_map; i++) {
 272                 if (e820.map[i].type != E820_RAM)
 273                         continue;
 274                 break;
 275         }
 276         if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
 277                 return -1;
 278         *addr = e820.map[i].addr;
 279         *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
 280                 max_pfn << PAGE_SHIFT) - *addr;
 281         return i + 1;
 282 }