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