arch/blackfin/kernel/cplb-mpu/cplbmgr.c

   1 /*
   2  * Blackfin CPLB exception handling for when MPU in on
   3  *
   4  * Copyright 2008-2009 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/mm.h>
  11
  12 #include <asm/blackfin.h>
  13 #include <asm/cacheflush.h>
  14 #include <asm/cplb.h>
  15 #include <asm/cplbinit.h>
  16 #include <asm/mmu_context.h>
  17
  18 /*
  19  * WARNING
  20  *
  21  * This file is compiled with certain -ffixed-reg options.  We have to
  22  * make sure not to call any functions here that could clobber these
  23  * registers.
  24  */
  25
  26 int page_mask_nelts;
  27 int page_mask_order;
  28 unsigned long *current_rwx_mask[NR_CPUS];
  29
  30 int nr_dcplb_miss[NR_CPUS], nr_icplb_miss[NR_CPUS];
  31 int nr_icplb_supv_miss[NR_CPUS], nr_dcplb_prot[NR_CPUS];
  32 int nr_cplb_flush[NR_CPUS];
  33
  34 #ifdef CONFIG_EXCPT_IRQ_SYSC_L1
  35 #define MGR_ATTR __attribute__((l1_text))
  36 #else
  37 #define MGR_ATTR
  38 #endif
  39
  40 /*
  41  * Given the contents of the status register, return the index of the
  42  * CPLB that caused the fault.
  43  */
  44 static inline int faulting_cplb_index(int status)
  45 {
  46         int signbits = __builtin_bfin_norm_fr1x32(status & 0xFFFF);
  47         return 30 - signbits;
  48 }
  49
  50 /*
  51  * Given the contents of the status register and the DCPLB_DATA contents,
  52  * return true if a write access should be permitted.
  53  */
  54 static inline int write_permitted(int status, unsigned long data)
  55 {
  56         if (status & FAULT_USERSUPV)
  57                 return !!(data & CPLB_SUPV_WR);
  58         else
  59                 return !!(data & CPLB_USER_WR);
  60 }
  61
  62 /* Counters to implement round-robin replacement.  */
  63 static int icplb_rr_index[NR_CPUS], dcplb_rr_index[NR_CPUS];
  64
  65 /*
  66  * Find an ICPLB entry to be evicted and return its index.
  67  */
  68 MGR_ATTR static int evict_one_icplb(unsigned int cpu)
  69 {
  70         int i;
  71         for (i = first_switched_icplb; i < MAX_CPLBS; i++)
  72                 if ((icplb_tbl[cpu][i].data & CPLB_VALID) == 0)
  73                         return i;
  74         i = first_switched_icplb + icplb_rr_index[cpu];
  75         if (i >= MAX_CPLBS) {
  76                 i -= MAX_CPLBS - first_switched_icplb;
  77                 icplb_rr_index[cpu] -= MAX_CPLBS - first_switched_icplb;
  78         }
  79         icplb_rr_index[cpu]++;
  80         return i;
  81 }
  82
  83 MGR_ATTR static int evict_one_dcplb(unsigned int cpu)
  84 {
  85         int i;
  86         for (i = first_switched_dcplb; i < MAX_CPLBS; i++)
  87                 if ((dcplb_tbl[cpu][i].data & CPLB_VALID) == 0)
  88                         return i;
  89         i = first_switched_dcplb + dcplb_rr_index[cpu];
  90         if (i >= MAX_CPLBS) {
  91                 i -= MAX_CPLBS - first_switched_dcplb;
  92                 dcplb_rr_index[cpu] -= MAX_CPLBS - first_switched_dcplb;
  93         }
  94         dcplb_rr_index[cpu]++;
  95         return i;
  96 }
  97
  98 MGR_ATTR static noinline int dcplb_miss(unsigned int cpu)
  99 {
 100         unsigned long addr = bfin_read_DCPLB_FAULT_ADDR();
 101         int status = bfin_read_DCPLB_STATUS();
 102         unsigned long *mask;
 103         int idx;
 104         unsigned long d_data;
 105
 106         nr_dcplb_miss[cpu]++;
 107
 108         d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
 109 #ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
 110         if (bfin_addr_dcacheable(addr)) {
 111                 d_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
 112 # ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
 113                 d_data |= CPLB_L1_AOW | CPLB_WT;
 114 # endif
 115         }
 116 #endif
 117
 118         if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
 119                 addr = L2_START;
 120                 d_data = L2_DMEMORY;
 121         } else if (addr >= physical_mem_end) {
 122                 if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
 123                         mask = current_rwx_mask[cpu];
 124                         if (mask) {
 125                                 int page = (addr - (ASYNC_BANK0_BASE - _ramend)) >> PAGE_SHIFT;
 126                                 int idx = page >> 5;
 127                                 int bit = 1 << (page & 31);
 128
 129                                 if (mask[idx] & bit)
 130                                         d_data |= CPLB_USER_RD;
 131                         }
 132                 } else if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
 133                     && (status & (FAULT_RW | FAULT_USERSUPV)) == FAULT_USERSUPV) {
 134                         addr &= ~(1 * 1024 * 1024 - 1);
 135                         d_data &= ~PAGE_SIZE_4KB;
 136                         d_data |= PAGE_SIZE_1MB;
 137                 } else
 138                         return CPLB_PROT_VIOL;
 139         } else if (addr >= _ramend) {
 140                 d_data |= CPLB_USER_RD | CPLB_USER_WR;
 141                 if (reserved_mem_dcache_on)
 142                         d_data |= CPLB_L1_CHBL;
 143         } else {
 144                 mask = current_rwx_mask[cpu];
 145                 if (mask) {
 146                         int page = addr >> PAGE_SHIFT;
 147                         int idx = page >> 5;
 148                         int bit = 1 << (page & 31);
 149
 150                         if (mask[idx] & bit)
 151                                 d_data |= CPLB_USER_RD;
 152
 153                         mask += page_mask_nelts;
 154                         if (mask[idx] & bit)
 155                                 d_data |= CPLB_USER_WR;
 156                 }
 157         }
 158         idx = evict_one_dcplb(cpu);
 159
 160         addr &= PAGE_MASK;
 161         dcplb_tbl[cpu][idx].addr = addr;
 162         dcplb_tbl[cpu][idx].data = d_data;
 163
 164         _disable_dcplb();
 165         bfin_write32(DCPLB_DATA0 + idx * 4, d_data);
 166         bfin_write32(DCPLB_ADDR0 + idx * 4, addr);
 167         _enable_dcplb();
 168
 169         return 0;
 170 }
 171
 172 MGR_ATTR static noinline int icplb_miss(unsigned int cpu)
 173 {
 174         unsigned long addr = bfin_read_ICPLB_FAULT_ADDR();
 175         int status = bfin_read_ICPLB_STATUS();
 176         int idx;
 177         unsigned long i_data;
 178
 179         nr_icplb_miss[cpu]++;
 180
 181         /* If inside the uncached DMA region, fault.  */
 182         if (addr >= _ramend - DMA_UNCACHED_REGION && addr < _ramend)
 183                 return CPLB_PROT_VIOL;
 184
 185         if (status & FAULT_USERSUPV)
 186                 nr_icplb_supv_miss[cpu]++;
 187
 188         /*
 189          * First, try to find a CPLB that matches this address.  If we
 190          * find one, then the fact that we're in the miss handler means
 191          * that the instruction crosses a page boundary.
 192          */
 193         for (idx = first_switched_icplb; idx < MAX_CPLBS; idx++) {
 194                 if (icplb_tbl[cpu][idx].data & CPLB_VALID) {
 195                         unsigned long this_addr = icplb_tbl[cpu][idx].addr;
 196                         if (this_addr <= addr && this_addr + PAGE_SIZE > addr) {
 197                                 addr += PAGE_SIZE;
 198                                 break;
 199                         }
 200                 }
 201         }
 202
 203         i_data = CPLB_VALID | CPLB_PORTPRIO | PAGE_SIZE_4KB;
 204
 205 #ifdef CONFIG_BFIN_EXTMEM_ICACHEABLE
 206         /*
 207          * Normal RAM, and possibly the reserved memory area, are
 208          * cacheable.
 209          */
 210         if (addr < _ramend ||
 211             (addr < physical_mem_end && reserved_mem_icache_on))
 212                 i_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
 213 #endif
 214
 215         if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
 216                 addr = L2_START;
 217                 i_data = L2_IMEMORY;
 218         } else if (addr >= physical_mem_end) {
 219                 if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
 220                         if (!(status & FAULT_USERSUPV)) {
 221                                 unsigned long *mask = current_rwx_mask[cpu];
 222
 223                                 if (mask) {
 224                                         int page = (addr - (ASYNC_BANK0_BASE - _ramend)) >> PAGE_SHIFT;
 225                                         int idx = page >> 5;
 226                                         int bit = 1 << (page & 31);
 227
 228                                         mask += 2 * page_mask_nelts;
 229                                         if (mask[idx] & bit)
 230                                                 i_data |= CPLB_USER_RD;
 231                                 }
 232                         }
 233                 } else if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
 234                     && (status & FAULT_USERSUPV)) {
 235                         addr &= ~(1 * 1024 * 1024 - 1);
 236                         i_data &= ~PAGE_SIZE_4KB;
 237                         i_data |= PAGE_SIZE_1MB;
 238                 } else
 239                     return CPLB_PROT_VIOL;
 240         } else if (addr >= _ramend) {
 241                 i_data |= CPLB_USER_RD;
 242                 if (reserved_mem_icache_on)
 243                         i_data |= CPLB_L1_CHBL;
 244         } else {
 245                 /*
 246                  * Two cases to distinguish - a supervisor access must
 247                  * necessarily be for a module page; we grant it
 248                  * unconditionally (could do better here in the future).
 249                  * Otherwise, check the x bitmap of the current process.
 250                  */
 251                 if (!(status & FAULT_USERSUPV)) {
 252                         unsigned long *mask = current_rwx_mask[cpu];
 253
 254                         if (mask) {
 255                                 int page = addr >> PAGE_SHIFT;
 256                                 int idx = page >> 5;
 257                                 int bit = 1 << (page & 31);
 258
 259                                 mask += 2 * page_mask_nelts;
 260                                 if (mask[idx] & bit)
 261                                         i_data |= CPLB_USER_RD;
 262                         }
 263                 }
 264         }
 265         idx = evict_one_icplb(cpu);
 266         addr &= PAGE_MASK;
 267         icplb_tbl[cpu][idx].addr = addr;
 268         icplb_tbl[cpu][idx].data = i_data;
 269
 270         _disable_icplb();
 271         bfin_write32(ICPLB_DATA0 + idx * 4, i_data);
 272         bfin_write32(ICPLB_ADDR0 + idx * 4, addr);
 273         _enable_icplb();
 274
 275         return 0;
 276 }
 277
 278 MGR_ATTR static noinline int dcplb_protection_fault(unsigned int cpu)
 279 {
 280         int status = bfin_read_DCPLB_STATUS();
 281
 282         nr_dcplb_prot[cpu]++;
 283
 284         if (status & FAULT_RW) {
 285                 int idx = faulting_cplb_index(status);
 286                 unsigned long data = dcplb_tbl[cpu][idx].data;
 287                 if (!(data & CPLB_WT) && !(data & CPLB_DIRTY) &&
 288                     write_permitted(status, data)) {
 289                         data |= CPLB_DIRTY;
 290                         dcplb_tbl[cpu][idx].data = data;
 291                         bfin_write32(DCPLB_DATA0 + idx * 4, data);
 292                         return 0;
 293                 }
 294         }
 295         return CPLB_PROT_VIOL;
 296 }
 297
 298 MGR_ATTR int cplb_hdr(int seqstat, struct pt_regs *regs)
 299 {
 300         int cause = seqstat & 0x3f;
 301         unsigned int cpu = raw_smp_processor_id();
 302         switch (cause) {
 303         case 0x23:
 304                 return dcplb_protection_fault(cpu);
 305         case 0x2C:
 306                 return icplb_miss(cpu);
 307         case 0x26:
 308                 return dcplb_miss(cpu);
 309         default:
 310                 return 1;
 311         }
 312 }
 313
 314 void flush_switched_cplbs(unsigned int cpu)
 315 {
 316         int i;
 317         unsigned long flags;
 318
 319         nr_cplb_flush[cpu]++;
 320
 321         flags = hard_local_irq_save();
 322         _disable_icplb();
 323         for (i = first_switched_icplb; i < MAX_CPLBS; i++) {
 324                 icplb_tbl[cpu][i].data = 0;
 325                 bfin_write32(ICPLB_DATA0 + i * 4, 0);
 326         }
 327         _enable_icplb();
 328
 329         _disable_dcplb();
 330         for (i = first_switched_dcplb; i < MAX_CPLBS; i++) {
 331                 dcplb_tbl[cpu][i].data = 0;
 332                 bfin_write32(DCPLB_DATA0 + i * 4, 0);
 333         }
 334         _enable_dcplb();
 335         hard_local_irq_restore(flags);
 336
 337 }
 338
 339 void set_mask_dcplbs(unsigned long *masks, unsigned int cpu)
 340 {
 341         int i;
 342         unsigned long addr = (unsigned long)masks;
 343         unsigned long d_data;
 344         unsigned long flags;
 345
 346         if (!masks) {
 347                 current_rwx_mask[cpu] = masks;
 348                 return;
 349         }
 350
 351         flags = hard_local_irq_save();
 352         current_rwx_mask[cpu] = masks;
 353
 354         if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
 355                 addr = L2_START;
 356                 d_data = L2_DMEMORY;
 357         } else {
 358                 d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
 359 #ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
 360                 d_data |= CPLB_L1_CHBL;
 361 # ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
 362                 d_data |= CPLB_L1_AOW | CPLB_WT;
 363 # endif
 364 #endif
 365         }
 366
 367         _disable_dcplb();
 368         for (i = first_mask_dcplb; i < first_switched_dcplb; i++) {
 369                 dcplb_tbl[cpu][i].addr = addr;
 370                 dcplb_tbl[cpu][i].data = d_data;
 371                 bfin_write32(DCPLB_DATA0 + i * 4, d_data);
 372                 bfin_write32(DCPLB_ADDR0 + i * 4, addr);
 373                 addr += PAGE_SIZE;
 374         }
 375         _enable_dcplb();
 376         hard_local_irq_restore(flags);
 377 }