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 /*
  43  * Powermanagement idle function, if any..
  44  */
  45 void (*pm_idle)(void) = NULL;
  46 EXPORT_SYMBOL(pm_idle);
  47
  48 void (*pm_power_off)(void) = NULL;
  49 EXPORT_SYMBOL(pm_power_off);
  50
  51 /*
  52  * The idle loop on BFIN
  53  */
  54 #ifdef CONFIG_IDLE_L1
  55 static void default_idle(void)__attribute__((l1_text));
  56 void cpu_idle(void)__attribute__((l1_text));
  57 #endif
  58
  59 /*
  60  * This is our default idle handler.  We need to disable
  61  * interrupts here to ensure we don't miss a wakeup call.
  62  */
  63 static void default_idle(void)
  64 {
  65 #ifdef CONFIG_IPIPE
  66         ipipe_suspend_domain();
  67 #endif
  68         hard_local_irq_disable();
  69         if (!need_resched())
  70                 idle_with_irq_disabled();
  71
  72         hard_local_irq_enable();
  73 }
  74
  75 /*
  76  * The idle thread.  We try to conserve power, while trying to keep
  77  * overall latency low.  The architecture specific idle is passed
  78  * a value to indicate the level of "idleness" of the system.
  79  */
  80 void cpu_idle(void)
  81 {
  82         /* endless idle loop with no priority at all */
  83         while (1) {
  84                 void (*idle)(void) = pm_idle;
  85
  86 #ifdef CONFIG_HOTPLUG_CPU
  87                 if (cpu_is_offline(smp_processor_id()))
  88                         cpu_die();
  89 #endif
  90                 if (!idle)
  91                         idle = default_idle;
  92                 tick_nohz_idle_enter();
  93                 rcu_idle_enter();
  94                 while (!need_resched())
  95                         idle();
  96                 rcu_idle_exit();
  97                 tick_nohz_idle_exit();
  98                 preempt_enable_no_resched();
  99                 schedule();
 100                 preempt_disable();
 101         }
 102 }
 103
 104 /*
 105  * Do necessary setup to start up a newly executed thread.
 106  *
 107  * pass the data segment into user programs if it exists,
 108  * it can't hurt anything as far as I can tell
 109  */
 110 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 111 {
 112         regs->pc = new_ip;
 113         if (current->mm)
 114                 regs->p5 = current->mm->start_data;
 115 #ifndef CONFIG_SMP
 116         task_thread_info(current)->l1_task_info.stack_start =
 117                 (void *)current->mm->context.stack_start;
 118         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 119         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 120                sizeof(*L1_SCRATCH_TASK_INFO));
 121 #endif
 122         wrusp(new_sp);
 123 }
 124 EXPORT_SYMBOL_GPL(start_thread);
 125
 126 void flush_thread(void)
 127 {
 128 }
 129
 130 asmlinkage int bfin_vfork(struct pt_regs *regs)
 131 {
 132         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 133                        NULL);
 134 }
 135
 136 asmlinkage int bfin_clone(struct pt_regs *regs)
 137 {
 138         unsigned long clone_flags;
 139         unsigned long newsp;
 140
 141 #ifdef __ARCH_SYNC_CORE_DCACHE
 142         if (current->nr_cpus_allowed == num_possible_cpus())
 143                 set_cpus_allowed_ptr(current, cpumask_of(smp_processor_id()));
 144 #endif
 145
 146         /* syscall2 puts clone_flags in r0 and usp in r1 */
 147         clone_flags = regs->r0;
 148         newsp = regs->r1;
 149         if (!newsp)
 150                 newsp = rdusp();
 151         else
 152                 newsp -= 12;
 153         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 154 }
 155
 156 int
 157 copy_thread(unsigned long clone_flags,
 158             unsigned long usp, unsigned long topstk,
 159             struct task_struct *p, struct pt_regs *regs)
 160 {
 161         struct pt_regs *childregs;
 162         unsigned long *v;
 163
 164         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 165         v = ((unsigned long *)childregs) - 2;
 166         if (unlikely(!regs)) {
 167                 memset(childregs, 0, sizeof(struct pt_regs));
 168                 v[0] = usp;
 169                 v[1] = topstk;
 170                 childregs->orig_p0 = -1;
 171                 childregs->ipend = 0x8000;
 172                 __asm__ __volatile__("%0 = syscfg;":"=da"(childregs->syscfg):);
 173                 p->thread.usp = 0;
 174         } else {
 175                 *childregs = *regs;
 176                 childregs->r0 = 0;
 177                 p->thread.usp = usp;
 178                 v[0] = v[1] = 0;
 179         }
 180
 181         p->thread.ksp = (unsigned long)v;
 182         p->thread.pc = (unsigned long)ret_from_fork;
 183
 184         return 0;
 185 }
 186
 187 unsigned long get_wchan(struct task_struct *p)
 188 {
 189         unsigned long fp, pc;
 190         unsigned long stack_page;
 191         int count = 0;
 192         if (!p || p == current || p->state == TASK_RUNNING)
 193                 return 0;
 194
 195         stack_page = (unsigned long)p;
 196         fp = p->thread.usp;
 197         do {
 198                 if (fp < stack_page + sizeof(struct thread_info) ||
 199                     fp >= 8184 + stack_page)
 200                         return 0;
 201                 pc = ((unsigned long *)fp)[1];
 202                 if (!in_sched_functions(pc))
 203                         return pc;
 204                 fp = *(unsigned long *)fp;
 205         }
 206         while (count++ < 16);
 207         return 0;
 208 }
 209
 210 void finish_atomic_sections (struct pt_regs *regs)
 211 {
 212         int __user *up0 = (int __user *)regs->p0;
 213
 214         switch (regs->pc) {
 215         default:
 216                 /* not in middle of an atomic step, so resume like normal */
 217                 return;
 218
 219         case ATOMIC_XCHG32 + 2:
 220                 put_user(regs->r1, up0);
 221                 break;
 222
 223         case ATOMIC_CAS32 + 2:
 224         case ATOMIC_CAS32 + 4:
 225                 if (regs->r0 == regs->r1)
 226         case ATOMIC_CAS32 + 6:
 227                         put_user(regs->r2, up0);
 228                 break;
 229
 230         case ATOMIC_ADD32 + 2:
 231                 regs->r0 = regs->r1 + regs->r0;
 232                 /* fall through */
 233         case ATOMIC_ADD32 + 4:
 234                 put_user(regs->r0, up0);
 235                 break;
 236
 237         case ATOMIC_SUB32 + 2:
 238                 regs->r0 = regs->r1 - regs->r0;
 239                 /* fall through */
 240         case ATOMIC_SUB32 + 4:
 241                 put_user(regs->r0, up0);
 242                 break;
 243
 244         case ATOMIC_IOR32 + 2:
 245                 regs->r0 = regs->r1 | regs->r0;
 246                 /* fall through */
 247         case ATOMIC_IOR32 + 4:
 248                 put_user(regs->r0, up0);
 249                 break;
 250
 251         case ATOMIC_AND32 + 2:
 252                 regs->r0 = regs->r1 & regs->r0;
 253                 /* fall through */
 254         case ATOMIC_AND32 + 4:
 255                 put_user(regs->r0, up0);
 256                 break;
 257
 258         case ATOMIC_XOR32 + 2:
 259                 regs->r0 = regs->r1 ^ regs->r0;
 260                 /* fall through */
 261         case ATOMIC_XOR32 + 4:
 262                 put_user(regs->r0, up0);
 263                 break;
 264         }
 265
 266         /*
 267          * We've finished the atomic section, and the only thing left for
 268          * userspace is to do a RTS, so we might as well handle that too
 269          * since we need to update the PC anyways.
 270          */
 271         regs->pc = regs->rets;
 272 }
 273
 274 static inline
 275 int in_mem(unsigned long addr, unsigned long size,
 276            unsigned long start, unsigned long end)
 277 {
 278         return addr >= start && addr + size <= end;
 279 }
 280 static inline
 281 int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
 282                      unsigned long const_addr, unsigned long const_size)
 283 {
 284         return const_size &&
 285                in_mem(addr, size, const_addr + off, const_addr + const_size);
 286 }
 287 static inline
 288 int in_mem_const(unsigned long addr, unsigned long size,
 289                  unsigned long const_addr, unsigned long const_size)
 290 {
 291         return in_mem_const_off(addr, size, 0, const_addr, const_size);
 292 }
 293 #ifdef CONFIG_BF60x
 294 #define ASYNC_ENABLED(bnum, bctlnum)    1
 295 #else
 296 #define ASYNC_ENABLED(bnum, bctlnum) \
 297 ({ \
 298         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? 0 : \
 299         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? 0 : \
 300         1; \
 301 })
 302 #endif
 303 /*
 304  * We can't read EBIU banks that aren't enabled or we end up hanging
 305  * on the access to the async space.  Make sure we validate accesses
 306  * that cross async banks too.
 307  *      0 - found, but unusable
 308  *      1 - found & usable
 309  *      2 - not found
 310  */
 311 static
 312 int in_async(unsigned long addr, unsigned long size)
 313 {
 314         if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE) {
 315                 if (!ASYNC_ENABLED(0, 0))
 316                         return 0;
 317                 if (addr + size <= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE)
 318                         return 1;
 319                 size -= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE - addr;
 320                 addr = ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE;
 321         }
 322         if (addr >= ASYNC_BANK1_BASE && addr < ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE) {
 323                 if (!ASYNC_ENABLED(1, 0))
 324                         return 0;
 325                 if (addr + size <= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE)
 326                         return 1;
 327                 size -= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE - addr;
 328                 addr = ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE;
 329         }
 330         if (addr >= ASYNC_BANK2_BASE && addr < ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE) {
 331                 if (!ASYNC_ENABLED(2, 1))
 332                         return 0;
 333                 if (addr + size <= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE)
 334                         return 1;
 335                 size -= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE - addr;
 336                 addr = ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE;
 337         }
 338         if (addr >= ASYNC_BANK3_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
 339                 if (ASYNC_ENABLED(3, 1))
 340                         return 0;
 341                 if (addr + size <= ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE)
 342                         return 1;
 343                 return 0;
 344         }
 345
 346         /* not within async bounds */
 347         return 2;
 348 }
 349
 350 int bfin_mem_access_type(unsigned long addr, unsigned long size)
 351 {
 352         int cpu = raw_smp_processor_id();
 353
 354         /* Check that things do not wrap around */
 355         if (addr > ULONG_MAX - size)
 356                 return -EFAULT;
 357
 358         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 359                 return BFIN_MEM_ACCESS_CORE;
 360
 361         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 362                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 363         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 364                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 365         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 366                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 367         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 368                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 369 #ifdef COREB_L1_CODE_START
 370         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 371                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 372         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 373                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 374         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 375                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 376         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 377                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 378 #endif
 379         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 380                 return BFIN_MEM_ACCESS_CORE;
 381
 382         if (addr >= SYSMMR_BASE)
 383                 return BFIN_MEM_ACCESS_CORE_ONLY;
 384
 385         switch (in_async(addr, size)) {
 386         case 0: return -EFAULT;
 387         case 1: return BFIN_MEM_ACCESS_CORE;
 388         case 2: /* fall through */;
 389         }
 390
 391         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 392                 return BFIN_MEM_ACCESS_CORE;
 393         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 394                 return BFIN_MEM_ACCESS_DMA;
 395
 396         return -EFAULT;
 397 }
 398
 399 #if defined(CONFIG_ACCESS_CHECK)
 400 #ifdef CONFIG_ACCESS_OK_L1
 401 __attribute__((l1_text))
 402 #endif
 403 /* Return 1 if access to memory range is OK, 0 otherwise */
 404 int _access_ok(unsigned long addr, unsigned long size)
 405 {
 406         int aret;
 407
 408         if (size == 0)
 409                 return 1;
 410         /* Check that things do not wrap around */
 411         if (addr > ULONG_MAX - size)
 412                 return 0;
 413         if (segment_eq(get_fs(), KERNEL_DS))
 414                 return 1;
 415 #ifdef CONFIG_MTD_UCLINUX
 416         if (1)
 417 #else
 418         if (0)
 419 #endif
 420         {
 421                 if (in_mem(addr, size, memory_start, memory_end))
 422                         return 1;
 423                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 424                         return 1;
 425 # ifndef CONFIG_ROMFS_ON_MTD
 426                 if (0)
 427 # endif
 428                         /* For XIP, allow user space to use pointers within the ROMFS.  */
 429                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 430                                 return 1;
 431         } else {
 432                 if (in_mem(addr, size, memory_start, physical_mem_end))
 433                         return 1;
 434         }
 435
 436         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 437                 return 1;
 438
 439         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 440                 return 1;
 441         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 442                 return 1;
 443         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 444                 return 1;
 445         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 446                 return 1;
 447 #ifdef COREB_L1_CODE_START
 448         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 449                 return 1;
 450         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 451                 return 1;
 452         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 453                 return 1;
 454         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 455                 return 1;
 456 #endif
 457
 458 #ifndef CONFIG_EXCEPTION_L1_SCRATCH
 459         if (in_mem_const(addr, size, (unsigned long)l1_stack_base, l1_stack_len))
 460                 return 1;
 461 #endif
 462
 463         aret = in_async(addr, size);
 464         if (aret < 2)
 465                 return aret;
 466
 467         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 468                 return 1;
 469
 470         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 471                 return 1;
 472         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 473                 return 1;
 474
 475         return 0;
 476 }
 477 EXPORT_SYMBOL(_access_ok);
 478 #endif /* CONFIG_ACCESS_CHECK */