arch/arm/mm/pmsa-v7.c

   1 /*
   2  * Based on linux/arch/arm/mm/nommu.c
   3  *
   4  * ARM PMSAv7 supporting functions.
   5  */
   6
   7 #include <linux/bitops.h>
   8 #include <linux/memblock.h>
   9 #include <linux/string.h>
  10
  11 #include <asm/cacheflush.h>
  12 #include <asm/cp15.h>
  13 #include <asm/cputype.h>
  14 #include <asm/mpu.h>
  15 #include <asm/sections.h>
  16
  17 #include "mm.h"
  18
  19 struct region {
  20         phys_addr_t base;
  21         phys_addr_t size;
  22         unsigned long subreg;
  23 };
  24
  25 static struct region __initdata mem[MPU_MAX_REGIONS];
  26 #ifdef CONFIG_XIP_KERNEL
  27 static struct region __initdata xip[MPU_MAX_REGIONS];
  28 #endif
  29
  30 static unsigned int __initdata mpu_min_region_order;
  31 static unsigned int __initdata mpu_max_regions;
  32
  33 static int __init __mpu_min_region_order(void);
  34 static int __init __mpu_max_regions(void);
  35
  36 #ifndef CONFIG_CPU_V7M
  37
  38 #define DRBAR   __ACCESS_CP15(c6, 0, c1, 0)
  39 #define IRBAR   __ACCESS_CP15(c6, 0, c1, 1)
  40 #define DRSR    __ACCESS_CP15(c6, 0, c1, 2)
  41 #define IRSR    __ACCESS_CP15(c6, 0, c1, 3)
  42 #define DRACR   __ACCESS_CP15(c6, 0, c1, 4)
  43 #define IRACR   __ACCESS_CP15(c6, 0, c1, 5)
  44 #define RNGNR   __ACCESS_CP15(c6, 0, c2, 0)
  45
  46 /* Region number */
  47 static inline void rgnr_write(u32 v)
  48 {
  49         write_sysreg(v, RNGNR);
  50 }
  51
  52 /* Data-side / unified region attributes */
  53
  54 /* Region access control register */
  55 static inline void dracr_write(u32 v)
  56 {
  57         write_sysreg(v, DRACR);
  58 }
  59
  60 /* Region size register */
  61 static inline void drsr_write(u32 v)
  62 {
  63         write_sysreg(v, DRSR);
  64 }
  65
  66 /* Region base address register */
  67 static inline void drbar_write(u32 v)
  68 {
  69         write_sysreg(v, DRBAR);
  70 }
  71
  72 static inline u32 drbar_read(void)
  73 {
  74         return read_sysreg(DRBAR);
  75 }
  76 /* Optional instruction-side region attributes */
  77
  78 /* I-side Region access control register */
  79 static inline void iracr_write(u32 v)
  80 {
  81         write_sysreg(v, IRACR);
  82 }
  83
  84 /* I-side Region size register */
  85 static inline void irsr_write(u32 v)
  86 {
  87         write_sysreg(v, IRSR);
  88 }
  89
  90 /* I-side Region base address register */
  91 static inline void irbar_write(u32 v)
  92 {
  93         write_sysreg(v, IRBAR);
  94 }
  95
  96 static inline u32 irbar_read(void)
  97 {
  98         return read_sysreg(IRBAR);
  99 }
 100
 101 #else
 102
 103 static inline void rgnr_write(u32 v)
 104 {
 105         writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv7_RNR);
 106 }
 107
 108 /* Data-side / unified region attributes */
 109
 110 /* Region access control register */
 111 static inline void dracr_write(u32 v)
 112 {
 113         u32 rsr = readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RASR) & GENMASK(15, 0);
 114
 115         writel_relaxed((v << 16) | rsr, BASEADDR_V7M_SCB + PMSAv7_RASR);
 116 }
 117
 118 /* Region size register */
 119 static inline void drsr_write(u32 v)
 120 {
 121         u32 racr = readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RASR) & GENMASK(31, 16);
 122
 123         writel_relaxed(v | racr, BASEADDR_V7M_SCB + PMSAv7_RASR);
 124 }
 125
 126 /* Region base address register */
 127 static inline void drbar_write(u32 v)
 128 {
 129         writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv7_RBAR);
 130 }
 131
 132 static inline u32 drbar_read(void)
 133 {
 134         return readl_relaxed(BASEADDR_V7M_SCB + PMSAv7_RBAR);
 135 }
 136
 137 /* ARMv7-M only supports a unified MPU, so I-side operations are nop */
 138
 139 static inline void iracr_write(u32 v) {}
 140 static inline void irsr_write(u32 v) {}
 141 static inline void irbar_write(u32 v) {}
 142 static inline unsigned long irbar_read(void) {return 0;}
 143
 144 #endif
 145
 146 static bool __init try_split_region(phys_addr_t base, phys_addr_t size, struct region *region)
 147 {
 148         unsigned long  subreg, bslots, sslots;
 149         phys_addr_t abase = base & ~(size - 1);
 150         phys_addr_t asize = base + size - abase;
 151         phys_addr_t p2size = 1 << __fls(asize);
 152         phys_addr_t bdiff, sdiff;
 153
 154         if (p2size != asize)
 155                 p2size *= 2;
 156
 157         bdiff = base - abase;
 158         sdiff = p2size - asize;
 159         subreg = p2size / PMSAv7_NR_SUBREGS;
 160
 161         if ((bdiff % subreg) || (sdiff % subreg))
 162                 return false;
 163
 164         bslots = bdiff / subreg;
 165         sslots = sdiff / subreg;
 166
 167         if (bslots || sslots) {
 168                 int i;
 169
 170                 if (subreg < PMSAv7_MIN_SUBREG_SIZE)
 171                         return false;
 172
 173                 if (bslots + sslots > PMSAv7_NR_SUBREGS)
 174                         return false;
 175
 176                 for (i = 0; i < bslots; i++)
 177                         _set_bit(i, &region->subreg);
 178
 179                 for (i = 1; i <= sslots; i++)
 180                         _set_bit(PMSAv7_NR_SUBREGS - i, &region->subreg);
 181         }
 182
 183         region->base = abase;
 184         region->size = p2size;
 185
 186         return true;
 187 }
 188
 189 static int __init allocate_region(phys_addr_t base, phys_addr_t size,
 190                                   unsigned int limit, struct region *regions)
 191 {
 192         int count = 0;
 193         phys_addr_t diff = size;
 194         int attempts = MPU_MAX_REGIONS;
 195
 196         while (diff) {
 197                 /* Try cover region as is (maybe with help of subregions) */
 198                 if (try_split_region(base, size, &regions[count])) {
 199                         count++;
 200                         base += size;
 201                         diff -= size;
 202                         size = diff;
 203                 } else {
 204                         /*
 205                          * Maximum aligned region might overflow phys_addr_t
 206                          * if "base" is 0. Hence we keep everything below 4G
 207                          * until we take the smaller of the aligned region
 208                          * size ("asize") and rounded region size ("p2size"),
 209                          * one of which is guaranteed to be smaller than the
 210                          * maximum physical address.
 211                          */
 212                         phys_addr_t asize = (base - 1) ^ base;
 213                         phys_addr_t p2size = (1 <<  __fls(diff)) - 1;
 214
 215                         size = asize < p2size ? asize + 1 : p2size + 1;
 216                 }
 217
 218                 if (count > limit)
 219                         break;
 220
 221                 if (!attempts)
 222                         break;
 223
 224                 attempts--;
 225         }
 226
 227         return count;
 228 }
 229
 230 /* MPU initialisation functions */
 231 void __init pmsav7_adjust_lowmem_bounds(void)
 232 {
 233         phys_addr_t  specified_mem_size = 0, total_mem_size = 0;
 234         struct memblock_region *reg;
 235         bool first = true;
 236         phys_addr_t mem_start;
 237         phys_addr_t mem_end;
 238         unsigned int mem_max_regions;
 239         int num, i;
 240
 241         /* Free-up PMSAv7_PROBE_REGION */
 242         mpu_min_region_order = __mpu_min_region_order();
 243
 244         /* How many regions are supported */
 245         mpu_max_regions = __mpu_max_regions();
 246
 247         mem_max_regions = min((unsigned int)MPU_MAX_REGIONS, mpu_max_regions);
 248
 249         /* We need to keep one slot for background region */
 250         mem_max_regions--;
 251
 252 #ifndef CONFIG_CPU_V7M
 253         /* ... and one for vectors */
 254         mem_max_regions--;
 255 #endif
 256
 257 #ifdef CONFIG_XIP_KERNEL
 258         /* plus some regions to cover XIP ROM */
 259         num = allocate_region(CONFIG_XIP_PHYS_ADDR, __pa(_exiprom) - CONFIG_XIP_PHYS_ADDR,
 260                               mem_max_regions, xip);
 261
 262         mem_max_regions -= num;
 263 #endif
 264
 265         for_each_memblock(memory, reg) {
 266                 if (first) {
 267                         phys_addr_t phys_offset = PHYS_OFFSET;
 268
 269                         /*
 270                          * Initially only use memory continuous from
 271                          * PHYS_OFFSET */
 272                         if (reg->base != phys_offset)
 273                                 panic("First memory bank must be contiguous from PHYS_OFFSET");
 274
 275                         mem_start = reg->base;
 276                         mem_end = reg->base + reg->size;
 277                         specified_mem_size = reg->size;
 278                         first = false;
 279                 } else {
 280                         /*
 281                          * memblock auto merges contiguous blocks, remove
 282                          * all blocks afterwards in one go (we can't remove
 283                          * blocks separately while iterating)
 284                          */
 285                         pr_notice("Ignoring RAM after %pa, memory at %pa ignored\n",
 286                                   &mem_end, &reg->base);
 287                         memblock_remove(reg->base, 0 - reg->base);
 288                         break;
 289                 }
 290         }
 291
 292         memset(mem, 0, sizeof(mem));
 293         num = allocate_region(mem_start, specified_mem_size, mem_max_regions, mem);
 294
 295         for (i = 0; i < num; i++) {
 296                 unsigned long  subreg = mem[i].size / PMSAv7_NR_SUBREGS;
 297
 298                 total_mem_size += mem[i].size - subreg * hweight_long(mem[i].subreg);
 299
 300                 pr_debug("MPU: base %pa size %pa disable subregions: %*pbl\n",
 301                          &mem[i].base, &mem[i].size, PMSAv7_NR_SUBREGS, &mem[i].subreg);
 302         }
 303
 304         if (total_mem_size != specified_mem_size) {
 305                 pr_warn("Truncating memory from %pa to %pa (MPU region constraints)",
 306                                 &specified_mem_size, &total_mem_size);
 307                 memblock_remove(mem_start + total_mem_size,
 308                                 specified_mem_size - total_mem_size);
 309         }
 310 }
 311
 312 static int __init __mpu_max_regions(void)
 313 {
 314         /*
 315          * We don't support a different number of I/D side regions so if we
 316          * have separate instruction and data memory maps then return
 317          * whichever side has a smaller number of supported regions.
 318          */
 319         u32 dregions, iregions, mpuir;
 320
 321         mpuir = read_cpuid_mputype();
 322
 323         dregions = iregions = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION;
 324
 325         /* Check for separate d-side and i-side memory maps */
 326         if (mpuir & MPUIR_nU)
 327                 iregions = (mpuir & MPUIR_IREGION_SZMASK) >> MPUIR_IREGION;
 328
 329         /* Use the smallest of the two maxima */
 330         return min(dregions, iregions);
 331 }
 332
 333 static int __init mpu_iside_independent(void)
 334 {
 335         /* MPUIR.nU specifies whether there is *not* a unified memory map */
 336         return read_cpuid_mputype() & MPUIR_nU;
 337 }
 338
 339 static int __init __mpu_min_region_order(void)
 340 {
 341         u32 drbar_result, irbar_result;
 342
 343         /* We've kept a region free for this probing */
 344         rgnr_write(PMSAv7_PROBE_REGION);
 345         isb();
 346         /*
 347          * As per ARM ARM, write 0xFFFFFFFC to DRBAR to find the minimum
 348          * region order
 349         */
 350         drbar_write(0xFFFFFFFC);
 351         drbar_result = irbar_result = drbar_read();
 352         drbar_write(0x0);
 353         /* If the MPU is non-unified, we use the larger of the two minima*/
 354         if (mpu_iside_independent()) {
 355                 irbar_write(0xFFFFFFFC);
 356                 irbar_result = irbar_read();
 357                 irbar_write(0x0);
 358         }
 359         isb(); /* Ensure that MPU region operations have completed */
 360         /* Return whichever result is larger */
 361
 362         return __ffs(max(drbar_result, irbar_result));
 363 }
 364
 365 static int __init mpu_setup_region(unsigned int number, phys_addr_t start,
 366                                    unsigned int size_order, unsigned int properties,
 367                                    unsigned int subregions, bool need_flush)
 368 {
 369         u32 size_data;
 370
 371         /* We kept a region free for probing resolution of MPU regions*/
 372         if (number > mpu_max_regions
 373             || number >= MPU_MAX_REGIONS)
 374                 return -ENOENT;
 375
 376         if (size_order > 32)
 377                 return -ENOMEM;
 378
 379         if (size_order < mpu_min_region_order)
 380                 return -ENOMEM;
 381
 382         /* Writing N to bits 5:1 (RSR_SZ)  specifies region size 2^N+1 */
 383         size_data = ((size_order - 1) << PMSAv7_RSR_SZ) | 1 << PMSAv7_RSR_EN;
 384         size_data |= subregions << PMSAv7_RSR_SD;
 385
 386         if (need_flush)
 387                 flush_cache_all();
 388
 389         dsb(); /* Ensure all previous data accesses occur with old mappings */
 390         rgnr_write(number);
 391         isb();
 392         drbar_write(start);
 393         dracr_write(properties);
 394         isb(); /* Propagate properties before enabling region */
 395         drsr_write(size_data);
 396
 397         /* Check for independent I-side registers */
 398         if (mpu_iside_independent()) {
 399                 irbar_write(start);
 400                 iracr_write(properties);
 401                 isb();
 402                 irsr_write(size_data);
 403         }
 404         isb();
 405
 406         /* Store region info (we treat i/d side the same, so only store d) */
 407         mpu_rgn_info.rgns[number].dracr = properties;
 408         mpu_rgn_info.rgns[number].drbar = start;
 409         mpu_rgn_info.rgns[number].drsr = size_data;
 410
 411         mpu_rgn_info.used++;
 412
 413         return 0;
 414 }
 415
 416 /*
 417 * Set up default MPU regions, doing nothing if there is no MPU
 418 */
 419 void __init pmsav7_setup(void)
 420 {
 421         int i, region = 0, err = 0;
 422
 423         /* Setup MPU (order is important) */
 424
 425         /* Background */
 426         err |= mpu_setup_region(region++, 0, 32,
 427                                 PMSAv7_ACR_XN | PMSAv7_RGN_STRONGLY_ORDERED | PMSAv7_AP_PL1RW_PL0RW,
 428                                 0, false);
 429
 430 #ifdef CONFIG_XIP_KERNEL
 431         /* ROM */
 432         for (i = 0; i < ARRAY_SIZE(xip); i++) {
 433                 /*
 434                  * In case we overwrite RAM region we set earlier in
 435                  * head-nommu.S (which is cachable) all subsequent
 436                  * data access till we setup RAM bellow would be done
 437                  * with BG region (which is uncachable), thus we need
 438                  * to clean and invalidate cache.
 439                  */
 440                 bool need_flush = region == PMSAv7_RAM_REGION;
 441
 442                 if (!xip[i].size)
 443                         continue;
 444
 445                 err |= mpu_setup_region(region++, xip[i].base, ilog2(xip[i].size),
 446                                         PMSAv7_AP_PL1RO_PL0NA | PMSAv7_RGN_NORMAL,
 447                                         xip[i].subreg, need_flush);
 448         }
 449 #endif
 450
 451         /* RAM */
 452         for (i = 0; i < ARRAY_SIZE(mem); i++) {
 453                 if (!mem[i].size)
 454                         continue;
 455
 456                 err |= mpu_setup_region(region++, mem[i].base, ilog2(mem[i].size),
 457                                         PMSAv7_AP_PL1RW_PL0RW | PMSAv7_RGN_NORMAL,
 458                                         mem[i].subreg, false);
 459         }
 460
 461         /* Vectors */
 462 #ifndef CONFIG_CPU_V7M
 463         err |= mpu_setup_region(region++, vectors_base, ilog2(2 * PAGE_SIZE),
 464                                 PMSAv7_AP_PL1RW_PL0NA | PMSAv7_RGN_NORMAL,
 465                                 0, false);
 466 #endif
 467         if (err) {
 468                 panic("MPU region initialization failure! %d", err);
 469         } else {
 470                 pr_info("Using ARMv7 PMSA Compliant MPU. "
 471                          "Region independence: %s, Used %d of %d regions\n",
 472                         mpu_iside_independent() ? "Yes" : "No",
 473                         mpu_rgn_info.used, mpu_max_regions);
 474         }
 475 }