arch/blackfin/kernel/process.c

   1 /*
   2  * Blackfin architecture-dependent process handling
   3  *
   4  * Copyright 2004-2009 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/unistd.h>
  11 #include <linux/user.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/slab.h>
  14 #include <linux/sched.h>
  15 #include <linux/tick.h>
  16 #include <linux/fs.h>
  17 #include <linux/err.h>
  18
  19 #include <asm/blackfin.h>
  20 #include <asm/fixed_code.h>
  21 #include <asm/mem_map.h>
  22 #include <asm/irq.h>
  23
  24 asmlinkage void ret_from_fork(void);
  25
  26 /* Points to the SDRAM backup memory for the stack that is currently in
  27  * L1 scratchpad memory.
  28  */
  29 void *current_l1_stack_save;
  30
  31 /* The number of tasks currently using a L1 stack area.  The SRAM is
  32  * allocated/deallocated whenever this changes from/to zero.
  33  */
  34 int nr_l1stack_tasks;
  35
  36 /* Start and length of the area in L1 scratchpad memory which we've allocated
  37  * for process stacks.
  38  */
  39 void *l1_stack_base;
  40 unsigned long l1_stack_len;
  41
  42 void (*pm_power_off)(void) = NULL;
  43 EXPORT_SYMBOL(pm_power_off);
  44
  45 /*
  46  * The idle loop on BFIN
  47  */
  48 #ifdef CONFIG_IDLE_L1
  49 static void default_idle(void)__attribute__((l1_text));
  50 void cpu_idle(void)__attribute__((l1_text));
  51 #endif
  52
  53 /*
  54  * This is our default idle handler.  We need to disable
  55  * interrupts here to ensure we don't miss a wakeup call.
  56  */
  57 static void default_idle(void)
  58 {
  59 #ifdef CONFIG_IPIPE
  60         ipipe_suspend_domain();
  61 #endif
  62         hard_local_irq_disable();
  63         if (!need_resched())
  64                 idle_with_irq_disabled();
  65
  66         hard_local_irq_enable();
  67 }
  68
  69 /*
  70  * The idle thread.  We try to conserve power, while trying to keep
  71  * overall latency low.  The architecture specific idle is passed
  72  * a value to indicate the level of "idleness" of the system.
  73  */
  74 void cpu_idle(void)
  75 {
  76         /* endless idle loop with no priority at all */
  77         while (1) {
  78
  79 #ifdef CONFIG_HOTPLUG_CPU
  80                 if (cpu_is_offline(smp_processor_id()))
  81                         cpu_die();
  82 #endif
  83                 if (!idle)
  84                         idle = default_idle;
  85                 tick_nohz_idle_enter();
  86                 rcu_idle_enter();
  87                 while (!need_resched())
  88                         idle();
  89                 rcu_idle_exit();
  90                 tick_nohz_idle_exit();
  91                 preempt_enable_no_resched();
  92                 schedule();
  93                 preempt_disable();
  94         }
  95 }
  96
  97 /*
  98  * Do necessary setup to start up a newly executed thread.
  99  *
 100  * pass the data segment into user programs if it exists,
 101  * it can't hurt anything as far as I can tell
 102  */
 103 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 104 {
 105         regs->pc = new_ip;
 106         if (current->mm)
 107                 regs->p5 = current->mm->start_data;
 108 #ifndef CONFIG_SMP
 109         task_thread_info(current)->l1_task_info.stack_start =
 110                 (void *)current->mm->context.stack_start;
 111         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 112         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 113                sizeof(*L1_SCRATCH_TASK_INFO));
 114 #endif
 115         wrusp(new_sp);
 116 }
 117 EXPORT_SYMBOL_GPL(start_thread);
 118
 119 void flush_thread(void)
 120 {
 121 }
 122
 123 asmlinkage int bfin_clone(unsigned long clone_flags, unsigned long newsp)
 124 {
 125 #ifdef __ARCH_SYNC_CORE_DCACHE
 126         if (current->nr_cpus_allowed == num_possible_cpus())
 127                 set_cpus_allowed_ptr(current, cpumask_of(smp_processor_id()));
 128 #endif
 129         if (newsp)
 130                 newsp -= 12;
 131         return do_fork(clone_flags, newsp, 0, NULL, NULL);
 132 }
 133
 134 int
 135 copy_thread(unsigned long clone_flags,
 136             unsigned long usp, unsigned long topstk,
 137             struct task_struct *p)
 138 {
 139         struct pt_regs *childregs;
 140         unsigned long *v;
 141
 142         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 143         v = ((unsigned long *)childregs) - 2;
 144         if (unlikely(p->flags & PF_KTHREAD)) {
 145                 memset(childregs, 0, sizeof(struct pt_regs));
 146                 v[0] = usp;
 147                 v[1] = topstk;
 148                 childregs->orig_p0 = -1;
 149                 childregs->ipend = 0x8000;
 150                 __asm__ __volatile__("%0 = syscfg;":"=da"(childregs->syscfg):);
 151                 p->thread.usp = 0;
 152         } else {
 153                 *childregs = *current_pt_regs();
 154                 childregs->r0 = 0;
 155                 p->thread.usp = usp ? : rdusp();
 156                 v[0] = v[1] = 0;
 157         }
 158
 159         p->thread.ksp = (unsigned long)v;
 160         p->thread.pc = (unsigned long)ret_from_fork;
 161
 162         return 0;
 163 }
 164
 165 unsigned long get_wchan(struct task_struct *p)
 166 {
 167         unsigned long fp, pc;
 168         unsigned long stack_page;
 169         int count = 0;
 170         if (!p || p == current || p->state == TASK_RUNNING)
 171                 return 0;
 172
 173         stack_page = (unsigned long)p;
 174         fp = p->thread.usp;
 175         do {
 176                 if (fp < stack_page + sizeof(struct thread_info) ||
 177                     fp >= 8184 + stack_page)
 178                         return 0;
 179                 pc = ((unsigned long *)fp)[1];
 180                 if (!in_sched_functions(pc))
 181                         return pc;
 182                 fp = *(unsigned long *)fp;
 183         }
 184         while (count++ < 16);
 185         return 0;
 186 }
 187
 188 void finish_atomic_sections (struct pt_regs *regs)
 189 {
 190         int __user *up0 = (int __user *)regs->p0;
 191
 192         switch (regs->pc) {
 193         default:
 194                 /* not in middle of an atomic step, so resume like normal */
 195                 return;
 196
 197         case ATOMIC_XCHG32 + 2:
 198                 put_user(regs->r1, up0);
 199                 break;
 200
 201         case ATOMIC_CAS32 + 2:
 202         case ATOMIC_CAS32 + 4:
 203                 if (regs->r0 == regs->r1)
 204         case ATOMIC_CAS32 + 6:
 205                         put_user(regs->r2, up0);
 206                 break;
 207
 208         case ATOMIC_ADD32 + 2:
 209                 regs->r0 = regs->r1 + regs->r0;
 210                 /* fall through */
 211         case ATOMIC_ADD32 + 4:
 212                 put_user(regs->r0, up0);
 213                 break;
 214
 215         case ATOMIC_SUB32 + 2:
 216                 regs->r0 = regs->r1 - regs->r0;
 217                 /* fall through */
 218         case ATOMIC_SUB32 + 4:
 219                 put_user(regs->r0, up0);
 220                 break;
 221
 222         case ATOMIC_IOR32 + 2:
 223                 regs->r0 = regs->r1 | regs->r0;
 224                 /* fall through */
 225         case ATOMIC_IOR32 + 4:
 226                 put_user(regs->r0, up0);
 227                 break;
 228
 229         case ATOMIC_AND32 + 2:
 230                 regs->r0 = regs->r1 & regs->r0;
 231                 /* fall through */
 232         case ATOMIC_AND32 + 4:
 233                 put_user(regs->r0, up0);
 234                 break;
 235
 236         case ATOMIC_XOR32 + 2:
 237                 regs->r0 = regs->r1 ^ regs->r0;
 238                 /* fall through */
 239         case ATOMIC_XOR32 + 4:
 240                 put_user(regs->r0, up0);
 241                 break;
 242         }
 243
 244         /*
 245          * We've finished the atomic section, and the only thing left for
 246          * userspace is to do a RTS, so we might as well handle that too
 247          * since we need to update the PC anyways.
 248          */
 249         regs->pc = regs->rets;
 250 }
 251
 252 static inline
 253 int in_mem(unsigned long addr, unsigned long size,
 254            unsigned long start, unsigned long end)
 255 {
 256         return addr >= start && addr + size <= end;
 257 }
 258 static inline
 259 int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
 260                      unsigned long const_addr, unsigned long const_size)
 261 {
 262         return const_size &&
 263                in_mem(addr, size, const_addr + off, const_addr + const_size);
 264 }
 265 static inline
 266 int in_mem_const(unsigned long addr, unsigned long size,
 267                  unsigned long const_addr, unsigned long const_size)
 268 {
 269         return in_mem_const_off(addr, size, 0, const_addr, const_size);
 270 }
 271 #ifdef CONFIG_BF60x
 272 #define ASYNC_ENABLED(bnum, bctlnum)    1
 273 #else
 274 #define ASYNC_ENABLED(bnum, bctlnum) \
 275 ({ \
 276         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? 0 : \
 277         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? 0 : \
 278         1; \
 279 })
 280 #endif
 281 /*
 282  * We can't read EBIU banks that aren't enabled or we end up hanging
 283  * on the access to the async space.  Make sure we validate accesses
 284  * that cross async banks too.
 285  *      0 - found, but unusable
 286  *      1 - found & usable
 287  *      2 - not found
 288  */
 289 static
 290 int in_async(unsigned long addr, unsigned long size)
 291 {
 292         if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE) {
 293                 if (!ASYNC_ENABLED(0, 0))
 294                         return 0;
 295                 if (addr + size <= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE)
 296                         return 1;
 297                 size -= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE - addr;
 298                 addr = ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE;
 299         }
 300         if (addr >= ASYNC_BANK1_BASE && addr < ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE) {
 301                 if (!ASYNC_ENABLED(1, 0))
 302                         return 0;
 303                 if (addr + size <= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE)
 304                         return 1;
 305                 size -= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE - addr;
 306                 addr = ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE;
 307         }
 308         if (addr >= ASYNC_BANK2_BASE && addr < ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE) {
 309                 if (!ASYNC_ENABLED(2, 1))
 310                         return 0;
 311                 if (addr + size <= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE)
 312                         return 1;
 313                 size -= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE - addr;
 314                 addr = ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE;
 315         }
 316         if (addr >= ASYNC_BANK3_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
 317                 if (ASYNC_ENABLED(3, 1))
 318                         return 0;
 319                 if (addr + size <= ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE)
 320                         return 1;
 321                 return 0;
 322         }
 323
 324         /* not within async bounds */
 325         return 2;
 326 }
 327
 328 int bfin_mem_access_type(unsigned long addr, unsigned long size)
 329 {
 330         int cpu = raw_smp_processor_id();
 331
 332         /* Check that things do not wrap around */
 333         if (addr > ULONG_MAX - size)
 334                 return -EFAULT;
 335
 336         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 337                 return BFIN_MEM_ACCESS_CORE;
 338
 339         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 340                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 341         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 342                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 343         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 344                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 345         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 346                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 347 #ifdef COREB_L1_CODE_START
 348         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 349                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 350         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 351                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 352         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 353                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 354         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 355                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 356 #endif
 357         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 358                 return BFIN_MEM_ACCESS_CORE;
 359
 360         if (addr >= SYSMMR_BASE)
 361                 return BFIN_MEM_ACCESS_CORE_ONLY;
 362
 363         switch (in_async(addr, size)) {
 364         case 0: return -EFAULT;
 365         case 1: return BFIN_MEM_ACCESS_CORE;
 366         case 2: /* fall through */;
 367         }
 368
 369         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 370                 return BFIN_MEM_ACCESS_CORE;
 371         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 372                 return BFIN_MEM_ACCESS_DMA;
 373
 374         return -EFAULT;
 375 }
 376
 377 #if defined(CONFIG_ACCESS_CHECK)
 378 #ifdef CONFIG_ACCESS_OK_L1
 379 __attribute__((l1_text))
 380 #endif
 381 /* Return 1 if access to memory range is OK, 0 otherwise */
 382 int _access_ok(unsigned long addr, unsigned long size)
 383 {
 384         int aret;
 385
 386         if (size == 0)
 387                 return 1;
 388         /* Check that things do not wrap around */
 389         if (addr > ULONG_MAX - size)
 390                 return 0;
 391         if (segment_eq(get_fs(), KERNEL_DS))
 392                 return 1;
 393 #ifdef CONFIG_MTD_UCLINUX
 394         if (1)
 395 #else
 396         if (0)
 397 #endif
 398         {
 399                 if (in_mem(addr, size, memory_start, memory_end))
 400                         return 1;
 401                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 402                         return 1;
 403 # ifndef CONFIG_ROMFS_ON_MTD
 404                 if (0)
 405 # endif
 406                         /* For XIP, allow user space to use pointers within the ROMFS.  */
 407                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 408                                 return 1;
 409         } else {
 410                 if (in_mem(addr, size, memory_start, physical_mem_end))
 411                         return 1;
 412         }
 413
 414         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 415                 return 1;
 416
 417         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 418                 return 1;
 419         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 420                 return 1;
 421         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 422                 return 1;
 423         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 424                 return 1;
 425 #ifdef COREB_L1_CODE_START
 426         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 427                 return 1;
 428         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 429                 return 1;
 430         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 431                 return 1;
 432         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 433                 return 1;
 434 #endif
 435
 436 #ifndef CONFIG_EXCEPTION_L1_SCRATCH
 437         if (in_mem_const(addr, size, (unsigned long)l1_stack_base, l1_stack_len))
 438                 return 1;
 439 #endif
 440
 441         aret = in_async(addr, size);
 442         if (aret < 2)
 443                 return aret;
 444
 445         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 446                 return 1;
 447
 448         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 449                 return 1;
 450         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 451                 return 1;
 452
 453         return 0;
 454 }
 455 EXPORT_SYMBOL(_access_ok);
 456 #endif /* CONFIG_ACCESS_CHECK */