drivers/firmware/efi/memmap.c

   1 /*
   2  * Common EFI memory map functions.
   3  */
   4
   5 #define pr_fmt(fmt) "efi: " fmt
   6
   7 #include <linux/init.h>
   8 #include <linux/kernel.h>
   9 #include <linux/efi.h>
  10 #include <linux/io.h>
  11 #include <asm/early_ioremap.h>
  12 #include <linux/memblock.h>
  13 #include <linux/slab.h>
  14
  15 static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size)
  16 {
  17         return memblock_alloc(size, 0);
  18 }
  19
  20 static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
  21 {
  22         unsigned int order = get_order(size);
  23         struct page *p = alloc_pages(GFP_KERNEL, order);
  24
  25         if (!p)
  26                 return 0;
  27
  28         return PFN_PHYS(page_to_pfn(p));
  29 }
  30
  31 /**
  32  * efi_memmap_alloc - Allocate memory for the EFI memory map
  33  * @num_entries: Number of entries in the allocated map.
  34  *
  35  * Depending on whether mm_init() has already been invoked or not,
  36  * either memblock or "normal" page allocation is used.
  37  *
  38  * Returns the physical address of the allocated memory map on
  39  * success, zero on failure.
  40  */
  41 phys_addr_t __init efi_memmap_alloc(unsigned int num_entries)
  42 {
  43         unsigned long size = num_entries * efi.memmap.desc_size;
  44
  45         if (slab_is_available())
  46                 return __efi_memmap_alloc_late(size);
  47
  48         return __efi_memmap_alloc_early(size);
  49 }
  50
  51 /**
  52  * __efi_memmap_init - Common code for mapping the EFI memory map
  53  * @data: EFI memory map data
  54  * @late: Use early or late mapping function?
  55  *
  56  * This function takes care of figuring out which function to use to
  57  * map the EFI memory map in efi.memmap based on how far into the boot
  58  * we are.
  59  *
  60  * During bootup @late should be %false since we only have access to
  61  * the early_memremap*() functions as the vmalloc space isn't setup.
  62  * Once the kernel is fully booted we can fallback to the more robust
  63  * memremap*() API.
  64  *
  65  * Returns zero on success, a negative error code on failure.
  66  */
  67 static int __init
  68 __efi_memmap_init(struct efi_memory_map_data *data, bool late)
  69 {
  70         struct efi_memory_map map;
  71         phys_addr_t phys_map;
  72
  73         if (efi_enabled(EFI_PARAVIRT))
  74                 return 0;
  75
  76         phys_map = data->phys_map;
  77
  78         if (late)
  79                 map.map = memremap(phys_map, data->size, MEMREMAP_WB);
  80         else
  81                 map.map = early_memremap(phys_map, data->size);
  82
  83         if (!map.map) {
  84                 pr_err("Could not map the memory map!\n");
  85                 return -ENOMEM;
  86         }
  87
  88         map.phys_map = data->phys_map;
  89         map.nr_map = data->size / data->desc_size;
  90         map.map_end = map.map + data->size;
  91
  92         map.desc_version = data->desc_version;
  93         map.desc_size = data->desc_size;
  94         map.late = late;
  95
  96         set_bit(EFI_MEMMAP, &efi.flags);
  97
  98         efi.memmap = map;
  99
 100         return 0;
 101 }
 102
 103 /**
 104  * efi_memmap_init_early - Map the EFI memory map data structure
 105  * @data: EFI memory map data
 106  *
 107  * Use early_memremap() to map the passed in EFI memory map and assign
 108  * it to efi.memmap.
 109  */
 110 int __init efi_memmap_init_early(struct efi_memory_map_data *data)
 111 {
 112         /* Cannot go backwards */
 113         WARN_ON(efi.memmap.late);
 114
 115         return __efi_memmap_init(data, false);
 116 }
 117
 118 void __init efi_memmap_unmap(void)
 119 {
 120         if (!efi.memmap.late) {
 121                 unsigned long size;
 122
 123                 size = efi.memmap.desc_size * efi.memmap.nr_map;
 124                 early_memunmap(efi.memmap.map, size);
 125         } else {
 126                 memunmap(efi.memmap.map);
 127         }
 128
 129         efi.memmap.map = NULL;
 130         clear_bit(EFI_MEMMAP, &efi.flags);
 131 }
 132
 133 /**
 134  * efi_memmap_init_late - Map efi.memmap with memremap()
 135  * @phys_addr: Physical address of the new EFI memory map
 136  * @size: Size in bytes of the new EFI memory map
 137  *
 138  * Setup a mapping of the EFI memory map using ioremap_cache(). This
 139  * function should only be called once the vmalloc space has been
 140  * setup and is therefore not suitable for calling during early EFI
 141  * initialise, e.g. in efi_init(). Additionally, it expects
 142  * efi_memmap_init_early() to have already been called.
 143  *
 144  * The reason there are two EFI memmap initialisation
 145  * (efi_memmap_init_early() and this late version) is because the
 146  * early EFI memmap should be explicitly unmapped once EFI
 147  * initialisation is complete as the fixmap space used to map the EFI
 148  * memmap (via early_memremap()) is a scarce resource.
 149  *
 150  * This late mapping is intended to persist for the duration of
 151  * runtime so that things like efi_mem_desc_lookup() and
 152  * efi_mem_attributes() always work.
 153  *
 154  * Returns zero on success, a negative error code on failure.
 155  */
 156 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
 157 {
 158         struct efi_memory_map_data data = {
 159                 .phys_map = addr,
 160                 .size = size,
 161         };
 162
 163         /* Did we forget to unmap the early EFI memmap? */
 164         WARN_ON(efi.memmap.map);
 165
 166         /* Were we already called? */
 167         WARN_ON(efi.memmap.late);
 168
 169         /*
 170          * It makes no sense to allow callers to register different
 171          * values for the following fields. Copy them out of the
 172          * existing early EFI memmap.
 173          */
 174         data.desc_version = efi.memmap.desc_version;
 175         data.desc_size = efi.memmap.desc_size;
 176
 177         return __efi_memmap_init(&data, true);
 178 }
 179
 180 /**
 181  * efi_memmap_install - Install a new EFI memory map in efi.memmap
 182  * @addr: Physical address of the memory map
 183  * @nr_map: Number of entries in the memory map
 184  *
 185  * Unlike efi_memmap_init_*(), this function does not allow the caller
 186  * to switch from early to late mappings. It simply uses the existing
 187  * mapping function and installs the new memmap.
 188  *
 189  * Returns zero on success, a negative error code on failure.
 190  */
 191 int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map)
 192 {
 193         struct efi_memory_map_data data;
 194
 195         efi_memmap_unmap();
 196
 197         data.phys_map = addr;
 198         data.size = efi.memmap.desc_size * nr_map;
 199         data.desc_version = efi.memmap.desc_version;
 200         data.desc_size = efi.memmap.desc_size;
 201
 202         return __efi_memmap_init(&data, efi.memmap.late);
 203 }
 204
 205 /**
 206  * efi_memmap_split_count - Count number of additional EFI memmap entries
 207  * @md: EFI memory descriptor to split
 208  * @range: Address range (start, end) to split around
 209  *
 210  * Returns the number of additional EFI memmap entries required to
 211  * accomodate @range.
 212  */
 213 int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range)
 214 {
 215         u64 m_start, m_end;
 216         u64 start, end;
 217         int count = 0;
 218
 219         start = md->phys_addr;
 220         end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
 221
 222         /* modifying range */
 223         m_start = range->start;
 224         m_end = range->end;
 225
 226         if (m_start <= start) {
 227                 /* split into 2 parts */
 228                 if (start < m_end && m_end < end)
 229                         count++;
 230         }
 231
 232         if (start < m_start && m_start < end) {
 233                 /* split into 3 parts */
 234                 if (m_end < end)
 235                         count += 2;
 236                 /* split into 2 parts */
 237                 if (end <= m_end)
 238                         count++;
 239         }
 240
 241         return count;
 242 }
 243
 244 /**
 245  * efi_memmap_insert - Insert a memory region in an EFI memmap
 246  * @old_memmap: The existing EFI memory map structure
 247  * @buf: Address of buffer to store new map
 248  * @mem: Memory map entry to insert
 249  *
 250  * It is suggested that you call efi_memmap_split_count() first
 251  * to see how large @buf needs to be.
 252  */
 253 void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
 254                               struct efi_mem_range *mem)
 255 {
 256         u64 m_start, m_end, m_attr;
 257         efi_memory_desc_t *md;
 258         u64 start, end;
 259         void *old, *new;
 260
 261         /* modifying range */
 262         m_start = mem->range.start;
 263         m_end = mem->range.end;
 264         m_attr = mem->attribute;
 265
 266         /*
 267          * The EFI memory map deals with regions in EFI_PAGE_SIZE
 268          * units. Ensure that the region described by 'mem' is aligned
 269          * correctly.
 270          */
 271         if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
 272             !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
 273                 WARN_ON(1);
 274                 return;
 275         }
 276
 277         for (old = old_memmap->map, new = buf;
 278              old < old_memmap->map_end;
 279              old += old_memmap->desc_size, new += old_memmap->desc_size) {
 280
 281                 /* copy original EFI memory descriptor */
 282                 memcpy(new, old, old_memmap->desc_size);
 283                 md = new;
 284                 start = md->phys_addr;
 285                 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
 286
 287                 if (m_start <= start && end <= m_end)
 288                         md->attribute |= m_attr;
 289
 290                 if (m_start <= start &&
 291                     (start < m_end && m_end < end)) {
 292                         /* first part */
 293                         md->attribute |= m_attr;
 294                         md->num_pages = (m_end - md->phys_addr + 1) >>
 295                                 EFI_PAGE_SHIFT;
 296                         /* latter part */
 297                         new += old_memmap->desc_size;
 298                         memcpy(new, old, old_memmap->desc_size);
 299                         md = new;
 300                         md->phys_addr = m_end + 1;
 301                         md->num_pages = (end - md->phys_addr + 1) >>
 302                                 EFI_PAGE_SHIFT;
 303                 }
 304
 305                 if ((start < m_start && m_start < end) && m_end < end) {
 306                         /* first part */
 307                         md->num_pages = (m_start - md->phys_addr) >>
 308                                 EFI_PAGE_SHIFT;
 309                         /* middle part */
 310                         new += old_memmap->desc_size;
 311                         memcpy(new, old, old_memmap->desc_size);
 312                         md = new;
 313                         md->attribute |= m_attr;
 314                         md->phys_addr = m_start;
 315                         md->num_pages = (m_end - m_start + 1) >>
 316                                 EFI_PAGE_SHIFT;
 317                         /* last part */
 318                         new += old_memmap->desc_size;
 319                         memcpy(new, old, old_memmap->desc_size);
 320                         md = new;
 321                         md->phys_addr = m_end + 1;
 322                         md->num_pages = (end - m_end) >>
 323                                 EFI_PAGE_SHIFT;
 324                 }
 325
 326                 if ((start < m_start && m_start < end) &&
 327                     (end <= m_end)) {
 328                         /* first part */
 329                         md->num_pages = (m_start - md->phys_addr) >>
 330                                 EFI_PAGE_SHIFT;
 331                         /* latter part */
 332                         new += old_memmap->desc_size;
 333                         memcpy(new, old, old_memmap->desc_size);
 334                         md = new;
 335                         md->phys_addr = m_start;
 336                         md->num_pages = (end - md->phys_addr + 1) >>
 337                                 EFI_PAGE_SHIFT;
 338                         md->attribute |= m_attr;
 339                 }
 340         }
 341 }