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/suspend.h>
  21 #include <linux/pfn.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 end_pfn;
  55
  56         end_pfn = find_max_pfn_with_active_regions();
  57
  58         if (end_pfn > max_pfn_mapped)
  59                 max_pfn_mapped = end_pfn;
  60         if (max_pfn_mapped > MAXMEM>>PAGE_SHIFT)
  61                 max_pfn_mapped = MAXMEM>>PAGE_SHIFT;
  62         if (end_pfn > end_user_pfn)
  63                 end_pfn = end_user_pfn;
  64         if (end_pfn > max_pfn_mapped)
  65                 end_pfn = max_pfn_mapped;
  66
  67         printk(KERN_INFO "max_pfn_mapped = %lu\n", max_pfn_mapped);
  68         return end_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  * Find the ranges of physical addresses that do not correspond to
  97  * e820 RAM areas and mark the corresponding pages as nosave for software
  98  * suspend and suspend to RAM.
  99  *
 100  * This function requires the e820 map to be sorted and without any
 101  * overlapping entries and assumes the first e820 area to be RAM.
 102  */
 103 void __init e820_mark_nosave_regions(void)
 104 {
 105         int i;
 106         unsigned long paddr;
 107
 108         paddr = round_down(e820.map[0].addr + e820.map[0].size, PAGE_SIZE);
 109         for (i = 1; i < e820.nr_map; i++) {
 110                 struct e820entry *ei = &e820.map[i];
 111
 112                 if (paddr < ei->addr)
 113                         register_nosave_region(PFN_DOWN(paddr),
 114                                                 PFN_UP(ei->addr));
 115
 116                 paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
 117                 if (ei->type != E820_RAM)
 118                         register_nosave_region(PFN_UP(ei->addr),
 119                                                 PFN_DOWN(paddr));
 120
 121                 if (paddr >= (end_pfn << PAGE_SHIFT))
 122                         break;
 123         }
 124 }
 125
 126 /*
 127  * Finds an active region in the address range from start_pfn to end_pfn and
 128  * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
 129  */
 130 static int __init e820_find_active_region(const struct e820entry *ei,
 131                                           unsigned long start_pfn,
 132                                           unsigned long end_pfn,
 133                                           unsigned long *ei_startpfn,
 134                                           unsigned long *ei_endpfn)
 135 {
 136         *ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
 137         *ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
 138
 139         /* Skip map entries smaller than a page */
 140         if (*ei_startpfn >= *ei_endpfn)
 141                 return 0;
 142
 143         /* Check if max_pfn_mapped should be updated */
 144         if (ei->type != E820_RAM && *ei_endpfn > max_pfn_mapped)
 145                 max_pfn_mapped = *ei_endpfn;
 146
 147         /* Skip if map is outside the node */
 148         if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
 149                                     *ei_startpfn >= end_pfn)
 150                 return 0;
 151
 152         /* Check for overlaps */
 153         if (*ei_startpfn < start_pfn)
 154                 *ei_startpfn = start_pfn;
 155         if (*ei_endpfn > end_pfn)
 156                 *ei_endpfn = end_pfn;
 157
 158         /* Obey end_user_pfn to save on memmap */
 159         if (*ei_startpfn >= end_user_pfn)
 160                 return 0;
 161         if (*ei_endpfn > end_user_pfn)
 162                 *ei_endpfn = end_user_pfn;
 163
 164         return 1;
 165 }
 166
 167 /* Walk the e820 map and register active regions within a node */
 168 void __init
 169 e820_register_active_regions(int nid, unsigned long start_pfn,
 170                                                         unsigned long end_pfn)
 171 {
 172         unsigned long ei_startpfn;
 173         unsigned long ei_endpfn;
 174         int i;
 175
 176         for (i = 0; i < e820.nr_map; i++)
 177                 if (e820_find_active_region(&e820.map[i],
 178                                             start_pfn, end_pfn,
 179                                             &ei_startpfn, &ei_endpfn))
 180                         add_active_range(nid, ei_startpfn, ei_endpfn);
 181 }
 182
 183 /*
 184  * Find the hole size (in bytes) in the memory range.
 185  * @start: starting address of the memory range to scan
 186  * @end: ending address of the memory range to scan
 187  */
 188 unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
 189 {
 190         unsigned long start_pfn = start >> PAGE_SHIFT;
 191         unsigned long end_pfn = end >> PAGE_SHIFT;
 192         unsigned long ei_startpfn, ei_endpfn, ram = 0;
 193         int i;
 194
 195         for (i = 0; i < e820.nr_map; i++) {
 196                 if (e820_find_active_region(&e820.map[i],
 197                                             start_pfn, end_pfn,
 198                                             &ei_startpfn, &ei_endpfn))
 199                         ram += ei_endpfn - ei_startpfn;
 200         }
 201         return end - start - (ram << PAGE_SHIFT);
 202 }
 203
 204 static void early_panic(char *msg)
 205 {
 206         early_printk(msg);
 207         panic(msg);
 208 }
 209
 210 /* We're not void only for x86 32-bit compat */
 211 char *__init machine_specific_memory_setup(void)
 212 {
 213         char *who = "BIOS-e820";
 214         int new_nr;
 215         /*
 216          * Try to copy the BIOS-supplied E820-map.
 217          *
 218          * Otherwise fake a memory map; one section from 0k->640k,
 219          * the next section from 1mb->appropriate_mem_k
 220          */
 221         new_nr = boot_params.e820_entries;
 222         sanitize_e820_map(boot_params.e820_map,
 223                         ARRAY_SIZE(boot_params.e820_map),
 224                         &new_nr);
 225         boot_params.e820_entries = new_nr;
 226         if (copy_e820_map(boot_params.e820_map, boot_params.e820_entries) < 0)
 227                 early_panic("Cannot find a valid memory map");
 228         printk(KERN_INFO "BIOS-provided physical RAM map:\n");
 229         e820_print_map(who);
 230
 231         /* In case someone cares... */
 232         return who;
 233 }
 234
 235 static int __init parse_memopt(char *p)
 236 {
 237         if (!p)
 238                 return -EINVAL;
 239         end_user_pfn = memparse(p, &p);
 240         end_user_pfn >>= PAGE_SHIFT;
 241         return 0;
 242 }
 243 early_param("mem", parse_memopt);
 244
 245 static int userdef __initdata;
 246
 247 static int __init parse_memmap_opt(char *p)
 248 {
 249         char *oldp;
 250         unsigned long long start_at, mem_size;
 251
 252         if (!strcmp(p, "exactmap")) {
 253 #ifdef CONFIG_CRASH_DUMP
 254                 /*
 255                  * If we are doing a crash dump, we still need to know
 256                  * the real mem size before original memory map is
 257                  * reset.
 258                  */
 259                 e820_register_active_regions(0, 0, -1UL);
 260                 saved_max_pfn = e820_end_of_ram();
 261                 remove_all_active_ranges();
 262 #endif
 263                 max_pfn_mapped = 0;
 264                 e820.nr_map = 0;
 265                 userdef = 1;
 266                 return 0;
 267         }
 268
 269         oldp = p;
 270         mem_size = memparse(p, &p);
 271         if (p == oldp)
 272                 return -EINVAL;
 273
 274         userdef = 1;
 275         if (*p == '@') {
 276                 start_at = memparse(p+1, &p);
 277                 add_memory_region(start_at, mem_size, E820_RAM);
 278         } else if (*p == '#') {
 279                 start_at = memparse(p+1, &p);
 280                 add_memory_region(start_at, mem_size, E820_ACPI);
 281         } else if (*p == '$') {
 282                 start_at = memparse(p+1, &p);
 283                 add_memory_region(start_at, mem_size, E820_RESERVED);
 284         } else {
 285                 end_user_pfn = (mem_size >> PAGE_SHIFT);
 286         }
 287         return *p == '\0' ? 0 : -EINVAL;
 288 }
 289 early_param("memmap", parse_memmap_opt);
 290
 291 void __init finish_e820_parsing(void)
 292 {
 293         if (userdef) {
 294                 int nr = e820.nr_map;
 295
 296                 if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &nr) < 0)
 297                         early_panic("Invalid user supplied memory map");
 298                 e820.nr_map = nr;
 299
 300                 printk(KERN_INFO "user-defined physical RAM map:\n");
 301                 e820_print_map("user");
 302         }
 303 }
 304
 305 int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)
 306 {
 307         int i;
 308
 309         if (slot < 0 || slot >= e820.nr_map)
 310                 return -1;
 311         for (i = slot; i < e820.nr_map; i++) {
 312                 if (e820.map[i].type != E820_RAM)
 313                         continue;
 314                 break;
 315         }
 316         if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))
 317                 return -1;
 318         *addr = e820.map[i].addr;
 319         *size = min_t(u64, e820.map[i].size + e820.map[i].addr,
 320                 max_pfn << PAGE_SHIFT) - *addr;
 321         return i + 1;
 322 }