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 > max_pfn_mapped)
  59                 max_pfn_mapped = last_pfn;
  60         if (max_pfn_mapped > MAXMEM>>PAGE_SHIFT)
  61                 max_pfn_mapped = MAXMEM>>PAGE_SHIFT;
  62         if (last_pfn > end_user_pfn)
  63                 last_pfn = end_user_pfn;
  64         if (last_pfn > max_pfn_mapped)
  65                 last_pfn = max_pfn_mapped;
  66
  67         printk(KERN_INFO "max_pfn_mapped = %lu\n", max_pfn_mapped);
  68         return last_pfn;
  69 }
  70
  71 /*
  72  * Mark e820 reserved areas as busy for the resource manager.
  73  */
  74 void __init e820_reserve_resources(void)
  75 {
  76         int i;
  77         struct resource *res;
  78
  79         res = alloc_bootmem_low(sizeof(struct resource) * e820.nr_map);
  80         for (i = 0; i < e820.nr_map; i++) {
  81                 switch (e820.map[i].type) {
  82                 case E820_RAM:  res->name = "System RAM"; break;
  83                 case E820_ACPI: res->name = "ACPI Tables"; break;
  84                 case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
  85                 default:        res->name = "reserved";
  86                 }
  87                 res->start = e820.map[i].addr;
  88                 res->end = res->start + e820.map[i].size - 1;
  89                 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  90                 insert_resource(&iomem_resource, res);
  91                 res++;
  92         }
  93 }
  94
  95 /*
  96  * Finds an active region in the address range from start_pfn to last_pfn and
  97  * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
  98  */
  99 static int __init e820_find_active_region(const struct e820entry *ei,
 100                                           unsigned long start_pfn,
 101                                           unsigned long last_pfn,
 102                                           unsigned long *ei_startpfn,
 103                                           unsigned long *ei_endpfn)
 104 {
 105         *ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
 106         *ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
 107
 108         /* Skip map entries smaller than a page */
 109         if (*ei_startpfn >= *ei_endpfn)
 110                 return 0;
 111
 112         /* Check if max_pfn_mapped should be updated */
 113         if (ei->type != E820_RAM && *ei_endpfn > max_pfn_mapped)
 114                 max_pfn_mapped = *ei_endpfn;
 115
 116         /* Skip if map is outside the node */
 117         if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
 118                                     *ei_startpfn >= last_pfn)
 119                 return 0;
 120
 121         /* Check for overlaps */
 122         if (*ei_startpfn < start_pfn)
 123                 *ei_startpfn = start_pfn;
 124         if (*ei_endpfn > last_pfn)
 125                 *ei_endpfn = last_pfn;
 126
 127         /* Obey end_user_pfn to save on memmap */
 128         if (*ei_startpfn >= end_user_pfn)
 129                 return 0;
 130         if (*ei_endpfn > end_user_pfn)
 131                 *ei_endpfn = end_user_pfn;
 132
 133         return 1;
 134 }
 135
 136 /* Walk the e820 map and register active regions within a node */
 137 void __init
 138 e820_register_active_regions(int nid, unsigned long start_pfn,
 139                                                         unsigned long last_pfn)
 140 {
 141         unsigned long ei_startpfn;
 142         unsigned long ei_endpfn;
 143         int i;
 144
 145         for (i = 0; i < e820.nr_map; i++)
 146                 if (e820_find_active_region(&e820.map[i],
 147                                             start_pfn, last_pfn,
 148                                             &ei_startpfn, &ei_endpfn))
 149                         add_active_range(nid, ei_startpfn, ei_endpfn);
 150 }
 151
 152 /*
 153  * Find the hole size (in bytes) in the memory range.
 154  * @start: starting address of the memory range to scan
 155  * @end: ending address of the memory range to scan
 156  */
 157 unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
 158 {
 159         unsigned long start_pfn = start >> PAGE_SHIFT;
 160         unsigned long last_pfn = end >> PAGE_SHIFT;
 161         unsigned long ei_startpfn, ei_endpfn, ram = 0;
 162         int i;
 163
 164         for (i = 0; i < e820.nr_map; i++) {
 165                 if (e820_find_active_region(&e820.map[i],
 166                                             start_pfn, last_pfn,
 167                                             &ei_startpfn, &ei_endpfn))
 168                         ram += ei_endpfn - ei_startpfn;
 169         }
 170         return end - start - (ram << PAGE_SHIFT);
 171 }
 172
 173 static void early_panic(char *msg)
 174 {
 175         early_printk(msg);
 176         panic(msg);
 177 }
 178
 179 /* We're not void only for x86 32-bit compat */
 180 char *__init machine_specific_memory_setup(void)
 181 {
 182         char *who = "BIOS-e820";
 183         int new_nr;
 184         /*
 185          * Try to copy the BIOS-supplied E820-map.
 186          *
 187          * Otherwise fake a memory map; one section from 0k->640k,
 188          * the next section from 1mb->appropriate_mem_k
 189          */
 190         new_nr = boot_params.e820_entries;
 191         sanitize_e820_map(boot_params.e820_map,
 192                         ARRAY_SIZE(boot_params.e820_map),
 193                         &new_nr);
 194         boot_params.e820_entries = new_nr;
 195         if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0)
 196                 early_panic("Cannot find a valid memory map");
 197         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 198         e820_print_map(who);
 199
 200         /* In case someone cares... */
 201         return who;
 202 }
 203
 204 static int __init parse_memopt(char *p)
 205 {
 206         if (!p)
 207                 return -EINVAL;
 208         end_user_pfn = memparse(p, &p);
 209         end_user_pfn >>= PAGE_SHIFT;
 210         return 0;
 211 }
 212 early_param("mem", parse_memopt);
 213
 214 static int userdef __initdata;
 215
 216 static int __init parse_memmap_opt(char *p)
 217 {
 218         char *oldp;
 219         unsigned long long start_at, mem_size;
 220
 221         if (!strcmp(p, "exactmap")) {
 222 #ifdef CONFIG_CRASH_DUMP
 223                 /*
 224                  * If we are doing a crash dump, we still need to know
 225                  * the real mem size before original memory map is
 226                  * reset.
 227                  */
 228                 e820_register_active_regions(0, 0, -1UL);
 229                 saved_max_pfn = e820_end_of_ram();
 230                 remove_all_active_ranges();
 231 #endif
 232                 max_pfn_mapped = 0;
 233                 e820.nr_map = 0;
 234                 userdef = 1;
 235                 return 0;
 236         }
 237
 238         oldp = p;
 239         mem_size = memparse(p, &p);
 240         if (p == oldp)
 241                 return -EINVAL;
 242
 243         userdef = 1;
 244         if (*p == '@') {
 245                 start_at = memparse(p+1, &p);
 246                 add_memory_region(start_at, mem_size, E820_RAM);
 247         } else if (*p == '#') {
 248                 start_at = memparse(p+1, &p);
 249                 add_memory_region(start_at, mem_size, E820_ACPI);
 250         } else if (*p == '$') {
 251                 start_at = memparse(p+1, &p);
 252                 add_memory_region(start_at, mem_size, E820_RESERVED);
 253         } else {
 254                 end_user_pfn = (mem_size >> PAGE_SHIFT);
 255         }
 256         return *p == '\0' ? 0 : -EINVAL;
 257 }
 258 early_param("memmap", parse_memmap_opt);
 259
 260 void __init finish_e820_parsing(void)
 261 {
 262         if (userdef) {
 263                 int nr = e820.nr_map;
 264
 265                 if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &nr) < 0)
 266                         early_panic("Invalid user supplied memory map");
 267                 e820.nr_map = nr;
 268
 269                 printk(KERN_INFO "user-defined physical RAM map:\n");
 270                 e820_print_map("user");
 271         }
 272 }
 273
 274 int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
 275 {
 276         int i;
 277
 278         if (slot < 0 || slot >= e820.nr_map)
 279                 return -1;
 280         for (i = slot; i < e820.nr_map; i++) {
 281                 if (e820.map[i].type != E820_RAM)
 282                         continue;
 283                 break;
 284         }
 285         if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
 286                 return -1;
 287         *addr = e820.map[i].addr;
 288         *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
 289                 max_pfn << PAGE_SHIFT) - *addr;
 290         return i + 1;
 291 }