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