mm/early_ioremap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Provide common bits of early_ioremap() support for architectures needing
   4  * temporary mappings during boot before ioremap() is available.
   5  *
   6  * This is mostly a direct copy of the x86 early_ioremap implementation.
   7  *
   8  * (C) Copyright 1995 1996, 2014 Linus Torvalds
   9  *
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/mm.h>
  17 #include <linux/vmalloc.h>
  18 #include <asm/fixmap.h>
  19 #include <asm/early_ioremap.h>
  20
  21 #ifdef CONFIG_MMU
  22 static int early_ioremap_debug __initdata;
  23
  24 static int __init early_ioremap_debug_setup(char *str)
  25 {
  26         early_ioremap_debug = 1;
  27
  28         return 0;
  29 }
  30 early_param("early_ioremap_debug", early_ioremap_debug_setup);
  31
  32 static int after_paging_init __initdata;
  33
  34 pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
  35                                                     unsigned long size,
  36                                                     pgprot_t prot)
  37 {
  38         return prot;
  39 }
  40
  41 void __init __weak early_ioremap_shutdown(void)
  42 {
  43 }
  44
  45 void __init early_ioremap_reset(void)
  46 {
  47         early_ioremap_shutdown();
  48         after_paging_init = 1;
  49 }
  50
  51 /*
  52  * Generally, ioremap() is available after paging_init() has been called.
  53  * Architectures wanting to allow early_ioremap after paging_init() can
  54  * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
  55  */
  56 #ifndef __late_set_fixmap
  57 static inline void __init __late_set_fixmap(enum fixed_addresses idx,
  58                                             phys_addr_t phys, pgprot_t prot)
  59 {
  60         BUG();
  61 }
  62 #endif
  63
  64 #ifndef __late_clear_fixmap
  65 static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
  66 {
  67         BUG();
  68 }
  69 #endif
  70
  71 static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
  72 static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
  73 static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
  74
  75 void __init early_ioremap_setup(void)
  76 {
  77         int i;
  78
  79         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  80                 if (WARN_ON(prev_map[i]))
  81                         break;
  82
  83         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  84                 slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
  85 }
  86
  87 static int __init check_early_ioremap_leak(void)
  88 {
  89         int count = 0;
  90         int i;
  91
  92         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  93                 if (prev_map[i])
  94                         count++;
  95
  96         if (WARN(count, KERN_WARNING
  97                  "Debug warning: early ioremap leak of %d areas detected.\n"
  98                  "please boot with early_ioremap_debug and report the dmesg.\n",
  99                  count))
 100                 return 1;
 101         return 0;
 102 }
 103 late_initcall(check_early_ioremap_leak);
 104
 105 static void __init __iomem *
 106 __early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
 107 {
 108         unsigned long offset;
 109         resource_size_t last_addr;
 110         unsigned int nrpages;
 111         enum fixed_addresses idx;
 112         int i, slot;
 113
 114         WARN_ON(system_state != SYSTEM_BOOTING);
 115
 116         slot = -1;
 117         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 118                 if (!prev_map[i]) {
 119                         slot = i;
 120                         break;
 121                 }
 122         }
 123
 124         if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
 125                  __func__, (u64)phys_addr, size))
 126                 return NULL;
 127
 128         /* Don't allow wraparound or zero size */
 129         last_addr = phys_addr + size - 1;
 130         if (WARN_ON(!size || last_addr < phys_addr))
 131                 return NULL;
 132
 133         prev_size[slot] = size;
 134         /*
 135          * Mappings have to be page-aligned
 136          */
 137         offset = offset_in_page(phys_addr);
 138         phys_addr &= PAGE_MASK;
 139         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 140
 141         /*
 142          * Mappings have to fit in the FIX_BTMAP area.
 143          */
 144         nrpages = size >> PAGE_SHIFT;
 145         if (WARN_ON(nrpages > NR_FIX_BTMAPS))
 146                 return NULL;
 147
 148         /*
 149          * Ok, go for it..
 150          */
 151         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 152         while (nrpages > 0) {
 153                 if (after_paging_init)
 154                         __late_set_fixmap(idx, phys_addr, prot);
 155                 else
 156                         __early_set_fixmap(idx, phys_addr, prot);
 157                 phys_addr += PAGE_SIZE;
 158                 --idx;
 159                 --nrpages;
 160         }
 161         WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
 162              __func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);
 163
 164         prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
 165         return prev_map[slot];
 166 }
 167
 168 void __init early_iounmap(void __iomem *addr, unsigned long size)
 169 {
 170         unsigned long virt_addr;
 171         unsigned long offset;
 172         unsigned int nrpages;
 173         enum fixed_addresses idx;
 174         int i, slot;
 175
 176         slot = -1;
 177         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 178                 if (prev_map[i] == addr) {
 179                         slot = i;
 180                         break;
 181                 }
 182         }
 183
 184         if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
 185                  addr, size))
 186                 return;
 187
 188         if (WARN(prev_size[slot] != size,
 189                  "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
 190                  addr, size, slot, prev_size[slot]))
 191                 return;
 192
 193         WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
 194              addr, size, slot);
 195
 196         virt_addr = (unsigned long)addr;
 197         if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
 198                 return;
 199
 200         offset = offset_in_page(virt_addr);
 201         nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
 202
 203         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 204         while (nrpages > 0) {
 205                 if (after_paging_init)
 206                         __late_clear_fixmap(idx);
 207                 else
 208                         __early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
 209                 --idx;
 210                 --nrpages;
 211         }
 212         prev_map[slot] = NULL;
 213 }
 214
 215 /* Remap an IO device */
 216 void __init __iomem *
 217 early_ioremap(resource_size_t phys_addr, unsigned long size)
 218 {
 219         return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
 220 }
 221
 222 /* Remap memory */
 223 void __init *
 224 early_memremap(resource_size_t phys_addr, unsigned long size)
 225 {
 226         pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
 227                                                      FIXMAP_PAGE_NORMAL);
 228
 229         return (__force void *)__early_ioremap(phys_addr, size, prot);
 230 }
 231 #ifdef FIXMAP_PAGE_RO
 232 void __init *
 233 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
 234 {
 235         pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
 236                                                      FIXMAP_PAGE_RO);
 237
 238         return (__force void *)__early_ioremap(phys_addr, size, prot);
 239 }
 240 #endif
 241
 242 #ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
 243 void __init *
 244 early_memremap_prot(resource_size_t phys_addr, unsigned long size,
 245                     unsigned long prot_val)
 246 {
 247         return (__force void *)__early_ioremap(phys_addr, size,
 248                                                __pgprot(prot_val));
 249 }
 250 #endif
 251
 252 #define MAX_MAP_CHUNK   (NR_FIX_BTMAPS << PAGE_SHIFT)
 253
 254 void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
 255 {
 256         unsigned long slop, clen;
 257         char *p;
 258
 259         while (size) {
 260                 slop = offset_in_page(src);
 261                 clen = size;
 262                 if (clen > MAX_MAP_CHUNK - slop)
 263                         clen = MAX_MAP_CHUNK - slop;
 264                 p = early_memremap(src & PAGE_MASK, clen + slop);
 265                 memcpy(dest, p + slop, clen);
 266                 early_memunmap(p, clen + slop);
 267                 dest += clen;
 268                 src += clen;
 269                 size -= clen;
 270         }
 271 }
 272
 273 #else /* CONFIG_MMU */
 274
 275 void __init __iomem *
 276 early_ioremap(resource_size_t phys_addr, unsigned long size)
 277 {
 278         return (__force void __iomem *)phys_addr;
 279 }
 280
 281 /* Remap memory */
 282 void __init *
 283 early_memremap(resource_size_t phys_addr, unsigned long size)
 284 {
 285         return (void *)phys_addr;
 286 }
 287 void __init *
 288 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
 289 {
 290         return (void *)phys_addr;
 291 }
 292
 293 void __init early_iounmap(void __iomem *addr, unsigned long size)
 294 {
 295 }
 296
 297 #endif /* CONFIG_MMU */
 298
 299
 300 void __init early_memunmap(void *addr, unsigned long size)
 301 {
 302         early_iounmap((__force void __iomem *)addr, size);
 303 }