mm/early_ioremap.c

   1 /*
   2  * Provide common bits of early_ioremap() support for architectures needing
   3  * temporary mappings during boot before ioremap() is available.
   4  *
   5  * This is mostly a direct copy of the x86 early_ioremap implementation.
   6  *
   7  * (C) Copyright 1995 1996, 2014 Linus Torvalds
   8  *
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/io.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/mm.h>
  16 #include <linux/vmalloc.h>
  17 #include <asm/fixmap.h>
  18 #include <asm/early_ioremap.h>
  19
  20 #ifdef CONFIG_MMU
  21 static int early_ioremap_debug __initdata;
  22
  23 static int __init early_ioremap_debug_setup(char *str)
  24 {
  25         early_ioremap_debug = 1;
  26
  27         return 0;
  28 }
  29 early_param("early_ioremap_debug", early_ioremap_debug_setup);
  30
  31 static int after_paging_init __initdata;
  32
  33 pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
  34                                                     unsigned long size,
  35                                                     pgprot_t prot)
  36 {
  37         return prot;
  38 }
  39
  40 void __init __weak early_ioremap_shutdown(void)
  41 {
  42 }
  43
  44 void __init early_ioremap_reset(void)
  45 {
  46         early_ioremap_shutdown();
  47         after_paging_init = 1;
  48 }
  49
  50 /*
  51  * Generally, ioremap() is available after paging_init() has been called.
  52  * Architectures wanting to allow early_ioremap after paging_init() can
  53  * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
  54  */
  55 #ifndef __late_set_fixmap
  56 static inline void __init __late_set_fixmap(enum fixed_addresses idx,
  57                                             phys_addr_t phys, pgprot_t prot)
  58 {
  59         BUG();
  60 }
  61 #endif
  62
  63 #ifndef __late_clear_fixmap
  64 static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
  65 {
  66         BUG();
  67 }
  68 #endif
  69
  70 static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
  71 static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
  72 static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
  73
  74 void __init early_ioremap_setup(void)
  75 {
  76         int i;
  77
  78         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  79                 if (WARN_ON(prev_map[i]))
  80                         break;
  81
  82         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  83                 slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
  84 }
  85
  86 static int __init check_early_ioremap_leak(void)
  87 {
  88         int count = 0;
  89         int i;
  90
  91         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  92                 if (prev_map[i])
  93                         count++;
  94
  95         if (WARN(count, KERN_WARNING
  96                  "Debug warning: early ioremap leak of %d areas detected.\n"
  97                  "please boot with early_ioremap_debug and report the dmesg.\n",
  98                  count))
  99                 return 1;
 100         return 0;
 101 }
 102 late_initcall(check_early_ioremap_leak);
 103
 104 static void __init __iomem *
 105 __early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
 106 {
 107         unsigned long offset;
 108         resource_size_t last_addr;
 109         unsigned int nrpages;
 110         enum fixed_addresses idx;
 111         int i, slot;
 112
 113         WARN_ON(system_state != SYSTEM_BOOTING);
 114
 115         slot = -1;
 116         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 117                 if (!prev_map[i]) {
 118                         slot = i;
 119                         break;
 120                 }
 121         }
 122
 123         if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
 124                  __func__, (u64)phys_addr, size))
 125                 return NULL;
 126
 127         /* Don't allow wraparound or zero size */
 128         last_addr = phys_addr + size - 1;
 129         if (WARN_ON(!size || last_addr < phys_addr))
 130                 return NULL;
 131
 132         prev_size[slot] = size;
 133         /*
 134          * Mappings have to be page-aligned
 135          */
 136         offset = offset_in_page(phys_addr);
 137         phys_addr &= PAGE_MASK;
 138         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 139
 140         /*
 141          * Mappings have to fit in the FIX_BTMAP area.
 142          */
 143         nrpages = size >> PAGE_SHIFT;
 144         if (WARN_ON(nrpages > NR_FIX_BTMAPS))
 145                 return NULL;
 146
 147         /*
 148          * Ok, go for it..
 149          */
 150         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 151         while (nrpages > 0) {
 152                 if (after_paging_init)
 153                         __late_set_fixmap(idx, phys_addr, prot);
 154                 else
 155                         __early_set_fixmap(idx, phys_addr, prot);
 156                 phys_addr += PAGE_SIZE;
 157                 --idx;
 158                 --nrpages;
 159         }
 160         WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
 161              __func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);
 162
 163         prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
 164         return prev_map[slot];
 165 }
 166
 167 void __init early_iounmap(void __iomem *addr, unsigned long size)
 168 {
 169         unsigned long virt_addr;
 170         unsigned long offset;
 171         unsigned int nrpages;
 172         enum fixed_addresses idx;
 173         int i, slot;
 174
 175         slot = -1;
 176         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 177                 if (prev_map[i] == addr) {
 178                         slot = i;
 179                         break;
 180                 }
 181         }
 182
 183         if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
 184                  addr, size))
 185                 return;
 186
 187         if (WARN(prev_size[slot] != size,
 188                  "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
 189                  addr, size, slot, prev_size[slot]))
 190                 return;
 191
 192         WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
 193              addr, size, slot);
 194
 195         virt_addr = (unsigned long)addr;
 196         if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
 197                 return;
 198
 199         offset = offset_in_page(virt_addr);
 200         nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
 201
 202         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 203         while (nrpages > 0) {
 204                 if (after_paging_init)
 205                         __late_clear_fixmap(idx);
 206                 else
 207                         __early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
 208                 --idx;
 209                 --nrpages;
 210         }
 211         prev_map[slot] = NULL;
 212 }
 213
 214 /* Remap an IO device */
 215 void __init __iomem *
 216 early_ioremap(resource_size_t phys_addr, unsigned long size)
 217 {
 218         return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
 219 }
 220
 221 /* Remap memory */
 222 void __init *
 223 early_memremap(resource_size_t phys_addr, unsigned long size)
 224 {
 225         pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
 226                                                      FIXMAP_PAGE_NORMAL);
 227
 228         return (__force void *)__early_ioremap(phys_addr, size, prot);
 229 }
 230 #ifdef FIXMAP_PAGE_RO
 231 void __init *
 232 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
 233 {
 234         pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
 235                                                      FIXMAP_PAGE_RO);
 236
 237         return (__force void *)__early_ioremap(phys_addr, size, prot);
 238 }
 239 #endif
 240
 241 #ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
 242 void __init *
 243 early_memremap_prot(resource_size_t phys_addr, unsigned long size,
 244                     unsigned long prot_val)
 245 {
 246         return (__force void *)__early_ioremap(phys_addr, size,
 247                                                __pgprot(prot_val));
 248 }
 249 #endif
 250
 251 #define MAX_MAP_CHUNK   (NR_FIX_BTMAPS << PAGE_SHIFT)
 252
 253 void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
 254 {
 255         unsigned long slop, clen;
 256         char *p;
 257
 258         while (size) {
 259                 slop = offset_in_page(src);
 260                 clen = size;
 261                 if (clen > MAX_MAP_CHUNK - slop)
 262                         clen = MAX_MAP_CHUNK - slop;
 263                 p = early_memremap(src & PAGE_MASK, clen + slop);
 264                 memcpy(dest, p + slop, clen);
 265                 early_memunmap(p, clen + slop);
 266                 dest += clen;
 267                 src += clen;
 268                 size -= clen;
 269         }
 270 }
 271
 272 #else /* CONFIG_MMU */
 273
 274 void __init __iomem *
 275 early_ioremap(resource_size_t phys_addr, unsigned long size)
 276 {
 277         return (__force void __iomem *)phys_addr;
 278 }
 279
 280 /* Remap memory */
 281 void __init *
 282 early_memremap(resource_size_t phys_addr, unsigned long size)
 283 {
 284         return (void *)phys_addr;
 285 }
 286 void __init *
 287 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
 288 {
 289         return (void *)phys_addr;
 290 }
 291
 292 void __init early_iounmap(void __iomem *addr, unsigned long size)
 293 {
 294 }
 295
 296 #endif /* CONFIG_MMU */
 297
 298
 299 void __init early_memunmap(void *addr, unsigned long size)
 300 {
 301         early_iounmap((__force void __iomem *)addr, size);
 302 }