drivers/firmware/efi/memmap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Common EFI memory map functions.
   4  */
   5
   6 #define pr_fmt(fmt) "efi: " fmt
   7
   8 #include <linux/init.h>
   9 #include <linux/kernel.h>
  10 #include <linux/efi.h>
  11 #include <linux/io.h>
  12 #include <asm/early_ioremap.h>
  13 #include <linux/memblock.h>
  14 #include <linux/slab.h>
  15
  16 static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size)
  17 {
  18         return memblock_alloc(size, 0);
  19 }
  20
  21 static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
  22 {
  23         unsigned int order = get_order(size);
  24         struct page *p = alloc_pages(GFP_KERNEL, order);
  25
  26         if (!p)
  27                 return 0;
  28
  29         return PFN_PHYS(page_to_pfn(p));
  30 }
  31
  32 /**
  33  * efi_memmap_alloc - Allocate memory for the EFI memory map
  34  * @num_entries: Number of entries in the allocated map.
  35  *
  36  * Depending on whether mm_init() has already been invoked or not,
  37  * either memblock or "normal" page allocation is used.
  38  *
  39  * Returns the physical address of the allocated memory map on
  40  * success, zero on failure.
  41  */
  42 phys_addr_t __init efi_memmap_alloc(unsigned int num_entries)
  43 {
  44         unsigned long size = num_entries * efi.memmap.desc_size;
  45
  46         if (slab_is_available())
  47                 return __efi_memmap_alloc_late(size);
  48
  49         return __efi_memmap_alloc_early(size);
  50 }
  51
  52 /**
  53  * __efi_memmap_init - Common code for mapping the EFI memory map
  54  * @data: EFI memory map data
  55  * @late: Use early or late mapping function?
  56  *
  57  * This function takes care of figuring out which function to use to
  58  * map the EFI memory map in efi.memmap based on how far into the boot
  59  * we are.
  60  *
  61  * During bootup @late should be %false since we only have access to
  62  * the early_memremap*() functions as the vmalloc space isn't setup.
  63  * Once the kernel is fully booted we can fallback to the more robust
  64  * memremap*() API.
  65  *
  66  * Returns zero on success, a negative error code on failure.
  67  */
  68 static int __init
  69 __efi_memmap_init(struct efi_memory_map_data *data, bool late)
  70 {
  71         struct efi_memory_map map;
  72         phys_addr_t phys_map;
  73
  74         if (efi_enabled(EFI_PARAVIRT))
  75                 return 0;
  76
  77         phys_map = data->phys_map;
  78
  79         if (late)
  80                 map.map = memremap(phys_map, data->size, MEMREMAP_WB);
  81         else
  82                 map.map = early_memremap(phys_map, data->size);
  83
  84         if (!map.map) {
  85                 pr_err("Could not map the memory map!\n");
  86                 return -ENOMEM;
  87         }
  88
  89         map.phys_map = data->phys_map;
  90         map.nr_map = data->size / data->desc_size;
  91         map.map_end = map.map + data->size;
  92
  93         map.desc_version = data->desc_version;
  94         map.desc_size = data->desc_size;
  95         map.late = late;
  96
  97         set_bit(EFI_MEMMAP, &efi.flags);
  98
  99         efi.memmap = map;
 100
 101         return 0;
 102 }
 103
 104 /**
 105  * efi_memmap_init_early - Map the EFI memory map data structure
 106  * @data: EFI memory map data
 107  *
 108  * Use early_memremap() to map the passed in EFI memory map and assign
 109  * it to efi.memmap.
 110  */
 111 int __init efi_memmap_init_early(struct efi_memory_map_data *data)
 112 {
 113         /* Cannot go backwards */
 114         WARN_ON(efi.memmap.late);
 115
 116         return __efi_memmap_init(data, false);
 117 }
 118
 119 void __init efi_memmap_unmap(void)
 120 {
 121         if (!efi.memmap.late) {
 122                 unsigned long size;
 123
 124                 size = efi.memmap.desc_size * efi.memmap.nr_map;
 125                 early_memunmap(efi.memmap.map, size);
 126         } else {
 127                 memunmap(efi.memmap.map);
 128         }
 129
 130         efi.memmap.map = NULL;
 131         clear_bit(EFI_MEMMAP, &efi.flags);
 132 }
 133
 134 /**
 135  * efi_memmap_init_late - Map efi.memmap with memremap()
 136  * @phys_addr: Physical address of the new EFI memory map
 137  * @size: Size in bytes of the new EFI memory map
 138  *
 139  * Setup a mapping of the EFI memory map using ioremap_cache(). This
 140  * function should only be called once the vmalloc space has been
 141  * setup and is therefore not suitable for calling during early EFI
 142  * initialise, e.g. in efi_init(). Additionally, it expects
 143  * efi_memmap_init_early() to have already been called.
 144  *
 145  * The reason there are two EFI memmap initialisation
 146  * (efi_memmap_init_early() and this late version) is because the
 147  * early EFI memmap should be explicitly unmapped once EFI
 148  * initialisation is complete as the fixmap space used to map the EFI
 149  * memmap (via early_memremap()) is a scarce resource.
 150  *
 151  * This late mapping is intended to persist for the duration of
 152  * runtime so that things like efi_mem_desc_lookup() and
 153  * efi_mem_attributes() always work.
 154  *
 155  * Returns zero on success, a negative error code on failure.
 156  */
 157 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
 158 {
 159         struct efi_memory_map_data data = {
 160                 .phys_map = addr,
 161                 .size = size,
 162         };
 163
 164         /* Did we forget to unmap the early EFI memmap? */
 165         WARN_ON(efi.memmap.map);
 166
 167         /* Were we already called? */
 168         WARN_ON(efi.memmap.late);
 169
 170         /*
 171          * It makes no sense to allow callers to register different
 172          * values for the following fields. Copy them out of the
 173          * existing early EFI memmap.
 174          */
 175         data.desc_version = efi.memmap.desc_version;
 176         data.desc_size = efi.memmap.desc_size;
 177
 178         return __efi_memmap_init(&data, true);
 179 }
 180
 181 /**
 182  * efi_memmap_install - Install a new EFI memory map in efi.memmap
 183  * @addr: Physical address of the memory map
 184  * @nr_map: Number of entries in the memory map
 185  *
 186  * Unlike efi_memmap_init_*(), this function does not allow the caller
 187  * to switch from early to late mappings. It simply uses the existing
 188  * mapping function and installs the new memmap.
 189  *
 190  * Returns zero on success, a negative error code on failure.
 191  */
 192 int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map)
 193 {
 194         struct efi_memory_map_data data;
 195
 196         efi_memmap_unmap();
 197
 198         data.phys_map = addr;
 199         data.size = efi.memmap.desc_size * nr_map;
 200         data.desc_version = efi.memmap.desc_version;
 201         data.desc_size = efi.memmap.desc_size;
 202
 203         return __efi_memmap_init(&data, efi.memmap.late);
 204 }
 205
 206 /**
 207  * efi_memmap_split_count - Count number of additional EFI memmap entries
 208  * @md: EFI memory descriptor to split
 209  * @range: Address range (start, end) to split around
 210  *
 211  * Returns the number of additional EFI memmap entries required to
 212  * accomodate @range.
 213  */
 214 int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range)
 215 {
 216         u64 m_start, m_end;
 217         u64 start, end;
 218         int count = 0;
 219
 220         start = md->phys_addr;
 221         end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
 222
 223         /* modifying range */
 224         m_start = range->start;
 225         m_end = range->end;
 226
 227         if (m_start <= start) {
 228                 /* split into 2 parts */
 229                 if (start < m_end && m_end < end)
 230                         count++;
 231         }
 232
 233         if (start < m_start && m_start < end) {
 234                 /* split into 3 parts */
 235                 if (m_end < end)
 236                         count += 2;
 237                 /* split into 2 parts */
 238                 if (end <= m_end)
 239                         count++;
 240         }
 241
 242         return count;
 243 }
 244
 245 /**
 246  * efi_memmap_insert - Insert a memory region in an EFI memmap
 247  * @old_memmap: The existing EFI memory map structure
 248  * @buf: Address of buffer to store new map
 249  * @mem: Memory map entry to insert
 250  *
 251  * It is suggested that you call efi_memmap_split_count() first
 252  * to see how large @buf needs to be.
 253  */
 254 void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
 255                               struct efi_mem_range *mem)
 256 {
 257         u64 m_start, m_end, m_attr;
 258         efi_memory_desc_t *md;
 259         u64 start, end;
 260         void *old, *new;
 261
 262         /* modifying range */
 263         m_start = mem->range.start;
 264         m_end = mem->range.end;
 265         m_attr = mem->attribute;
 266
 267         /*
 268          * The EFI memory map deals with regions in EFI_PAGE_SIZE
 269          * units. Ensure that the region described by 'mem' is aligned
 270          * correctly.
 271          */
 272         if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
 273             !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
 274                 WARN_ON(1);
 275                 return;
 276         }
 277
 278         for (old = old_memmap->map, new = buf;
 279              old < old_memmap->map_end;
 280              old += old_memmap->desc_size, new += old_memmap->desc_size) {
 281
 282                 /* copy original EFI memory descriptor */
 283                 memcpy(new, old, old_memmap->desc_size);
 284                 md = new;
 285                 start = md->phys_addr;
 286                 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
 287
 288                 if (m_start <= start && end <= m_end)
 289                         md->attribute |= m_attr;
 290
 291                 if (m_start <= start &&
 292                     (start < m_end && m_end < end)) {
 293                         /* first part */
 294                         md->attribute |= m_attr;
 295                         md->num_pages = (m_end - md->phys_addr + 1) >>
 296                                 EFI_PAGE_SHIFT;
 297                         /* latter part */
 298                         new += old_memmap->desc_size;
 299                         memcpy(new, old, old_memmap->desc_size);
 300                         md = new;
 301                         md->phys_addr = m_end + 1;
 302                         md->num_pages = (end - md->phys_addr + 1) >>
 303                                 EFI_PAGE_SHIFT;
 304                 }
 305
 306                 if ((start < m_start && m_start < end) && m_end < end) {
 307                         /* first part */
 308                         md->num_pages = (m_start - md->phys_addr) >>
 309                                 EFI_PAGE_SHIFT;
 310                         /* middle part */
 311                         new += old_memmap->desc_size;
 312                         memcpy(new, old, old_memmap->desc_size);
 313                         md = new;
 314                         md->attribute |= m_attr;
 315                         md->phys_addr = m_start;
 316                         md->num_pages = (m_end - m_start + 1) >>
 317                                 EFI_PAGE_SHIFT;
 318                         /* last part */
 319                         new += old_memmap->desc_size;
 320                         memcpy(new, old, old_memmap->desc_size);
 321                         md = new;
 322                         md->phys_addr = m_end + 1;
 323                         md->num_pages = (end - m_end) >>
 324                                 EFI_PAGE_SHIFT;
 325                 }
 326
 327                 if ((start < m_start && m_start < end) &&
 328                     (end <= m_end)) {
 329                         /* first part */
 330                         md->num_pages = (m_start - md->phys_addr) >>
 331                                 EFI_PAGE_SHIFT;
 332                         /* latter part */
 333                         new += old_memmap->desc_size;
 334                         memcpy(new, old, old_memmap->desc_size);
 335                         md = new;
 336                         md->phys_addr = m_start;
 337                         md->num_pages = (end - md->phys_addr + 1) >>
 338                                 EFI_PAGE_SHIFT;
 339                         md->attribute |= m_attr;
 340                 }
 341         }
 342 }