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
  23 asmlinkage void ret_from_fork(void);
  24
  25 /* Points to the SDRAM backup memory for the stack that is currently in
  26  * L1 scratchpad memory.
  27  */
  28 void *current_l1_stack_save;
  29
  30 /* The number of tasks currently using a L1 stack area.  The SRAM is
  31  * allocated/deallocated whenever this changes from/to zero.
  32  */
  33 int nr_l1stack_tasks;
  34
  35 /* Start and length of the area in L1 scratchpad memory which we've allocated
  36  * for process stacks.
  37  */
  38 void *l1_stack_base;
  39 unsigned long l1_stack_len;
  40
  41 /*
  42  * Powermanagement idle function, if any..
  43  */
  44 void (*pm_idle)(void) = NULL;
  45 EXPORT_SYMBOL(pm_idle);
  46
  47 void (*pm_power_off)(void) = NULL;
  48 EXPORT_SYMBOL(pm_power_off);
  49
  50 /*
  51  * The idle loop on BFIN
  52  */
  53 #ifdef CONFIG_IDLE_L1
  54 static void default_idle(void)__attribute__((l1_text));
  55 void cpu_idle(void)__attribute__((l1_text));
  56 #endif
  57
  58 /*
  59  * This is our default idle handler.  We need to disable
  60  * interrupts here to ensure we don't miss a wakeup call.
  61  */
  62 static void default_idle(void)
  63 {
  64 #ifdef CONFIG_IPIPE
  65         ipipe_suspend_domain();
  66 #endif
  67         hard_local_irq_disable();
  68         if (!need_resched())
  69                 idle_with_irq_disabled();
  70
  71         hard_local_irq_enable();
  72 }
  73
  74 /*
  75  * The idle thread.  We try to conserve power, while trying to keep
  76  * overall latency low.  The architecture specific idle is passed
  77  * a value to indicate the level of "idleness" of the system.
  78  */
  79 void cpu_idle(void)
  80 {
  81         /* endless idle loop with no priority at all */
  82         while (1) {
  83                 void (*idle)(void) = pm_idle;
  84
  85 #ifdef CONFIG_HOTPLUG_CPU
  86                 if (cpu_is_offline(smp_processor_id()))
  87                         cpu_die();
  88 #endif
  89                 if (!idle)
  90                         idle = default_idle;
  91                 tick_nohz_idle_enter();
  92                 rcu_idle_enter();
  93                 while (!need_resched())
  94                         idle();
  95                 rcu_idle_exit();
  96                 tick_nohz_idle_exit();
  97                 schedule_preempt_disabled();
  98         }
  99 }
 100
 101 /*
 102  * This gets run with P1 containing the
 103  * function to call, and R1 containing
 104  * the "args".  Note P0 is clobbered on the way here.
 105  */
 106 void kernel_thread_helper(void);
 107 __asm__(".section .text\n"
 108         ".align 4\n"
 109         "_kernel_thread_helper:\n\t"
 110         "\tsp += -12;\n\t"
 111         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 112
 113 /*
 114  * Create a kernel thread.
 115  */
 116 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 117 {
 118         struct pt_regs regs;
 119
 120         memset(&regs, 0, sizeof(regs));
 121
 122         regs.r1 = (unsigned long)arg;
 123         regs.p1 = (unsigned long)fn;
 124         regs.pc = (unsigned long)kernel_thread_helper;
 125         regs.orig_p0 = -1;
 126         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 127            mode.  */
 128         regs.ipend = 0x8002;
 129         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 130         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 131                        NULL);
 132 }
 133 EXPORT_SYMBOL(kernel_thread);
 134
 135 /*
 136  * Do necessary setup to start up a newly executed thread.
 137  *
 138  * pass the data segment into user programs if it exists,
 139  * it can't hurt anything as far as I can tell
 140  */
 141 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 142 {
 143         regs->pc = new_ip;
 144         if (current->mm)
 145                 regs->p5 = current->mm->start_data;
 146 #ifndef CONFIG_SMP
 147         task_thread_info(current)->l1_task_info.stack_start =
 148                 (void *)current->mm->context.stack_start;
 149         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 150         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 151                sizeof(*L1_SCRATCH_TASK_INFO));
 152 #endif
 153         wrusp(new_sp);
 154 }
 155 EXPORT_SYMBOL_GPL(start_thread);
 156
 157 void flush_thread(void)
 158 {
 159 }
 160
 161 asmlinkage int bfin_vfork(struct pt_regs *regs)
 162 {
 163         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 164                        NULL);
 165 }
 166
 167 asmlinkage int bfin_clone(struct pt_regs *regs)
 168 {
 169         unsigned long clone_flags;
 170         unsigned long newsp;
 171
 172 #ifdef __ARCH_SYNC_CORE_DCACHE
 173         if (current->rt.nr_cpus_allowed == num_possible_cpus())
 174                 set_cpus_allowed_ptr(current, cpumask_of(smp_processor_id()));
 175 #endif
 176
 177         /* syscall2 puts clone_flags in r0 and usp in r1 */
 178         clone_flags = regs->r0;
 179         newsp = regs->r1;
 180         if (!newsp)
 181                 newsp = rdusp();
 182         else
 183                 newsp -= 12;
 184         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 185 }
 186
 187 int
 188 copy_thread(unsigned long clone_flags,
 189             unsigned long usp, unsigned long topstk,
 190             struct task_struct *p, struct pt_regs *regs)
 191 {
 192         struct pt_regs *childregs;
 193
 194         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 195         *childregs = *regs;
 196         childregs->r0 = 0;
 197
 198         p->thread.usp = usp;
 199         p->thread.ksp = (unsigned long)childregs;
 200         p->thread.pc = (unsigned long)ret_from_fork;
 201
 202         return 0;
 203 }
 204
 205 /*
 206  * sys_execve() executes a new program.
 207  */
 208 asmlinkage int sys_execve(const char __user *name,
 209                           const char __user *const __user *argv,
 210                           const char __user *const __user *envp)
 211 {
 212         int error;
 213         char *filename;
 214         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 215
 216         filename = getname(name);
 217         error = PTR_ERR(filename);
 218         if (IS_ERR(filename))
 219                 return error;
 220         error = do_execve(filename, argv, envp, regs);
 221         putname(filename);
 222         return error;
 223 }
 224
 225 unsigned long get_wchan(struct task_struct *p)
 226 {
 227         unsigned long fp, pc;
 228         unsigned long stack_page;
 229         int count = 0;
 230         if (!p || p == current || p->state == TASK_RUNNING)
 231                 return 0;
 232
 233         stack_page = (unsigned long)p;
 234         fp = p->thread.usp;
 235         do {
 236                 if (fp < stack_page + sizeof(struct thread_info) ||
 237                     fp >= 8184 + stack_page)
 238                         return 0;
 239                 pc = ((unsigned long *)fp)[1];
 240                 if (!in_sched_functions(pc))
 241                         return pc;
 242                 fp = *(unsigned long *)fp;
 243         }
 244         while (count++ < 16);
 245         return 0;
 246 }
 247
 248 void finish_atomic_sections (struct pt_regs *regs)
 249 {
 250         int __user *up0 = (int __user *)regs->p0;
 251
 252         switch (regs->pc) {
 253         default:
 254                 /* not in middle of an atomic step, so resume like normal */
 255                 return;
 256
 257         case ATOMIC_XCHG32 + 2:
 258                 put_user(regs->r1, up0);
 259                 break;
 260
 261         case ATOMIC_CAS32 + 2:
 262         case ATOMIC_CAS32 + 4:
 263                 if (regs->r0 == regs->r1)
 264         case ATOMIC_CAS32 + 6:
 265                         put_user(regs->r2, up0);
 266                 break;
 267
 268         case ATOMIC_ADD32 + 2:
 269                 regs->r0 = regs->r1 + regs->r0;
 270                 /* fall through */
 271         case ATOMIC_ADD32 + 4:
 272                 put_user(regs->r0, up0);
 273                 break;
 274
 275         case ATOMIC_SUB32 + 2:
 276                 regs->r0 = regs->r1 - regs->r0;
 277                 /* fall through */
 278         case ATOMIC_SUB32 + 4:
 279                 put_user(regs->r0, up0);
 280                 break;
 281
 282         case ATOMIC_IOR32 + 2:
 283                 regs->r0 = regs->r1 | regs->r0;
 284                 /* fall through */
 285         case ATOMIC_IOR32 + 4:
 286                 put_user(regs->r0, up0);
 287                 break;
 288
 289         case ATOMIC_AND32 + 2:
 290                 regs->r0 = regs->r1 & regs->r0;
 291                 /* fall through */
 292         case ATOMIC_AND32 + 4:
 293                 put_user(regs->r0, up0);
 294                 break;
 295
 296         case ATOMIC_XOR32 + 2:
 297                 regs->r0 = regs->r1 ^ regs->r0;
 298                 /* fall through */
 299         case ATOMIC_XOR32 + 4:
 300                 put_user(regs->r0, up0);
 301                 break;
 302         }
 303
 304         /*
 305          * We've finished the atomic section, and the only thing left for
 306          * userspace is to do a RTS, so we might as well handle that too
 307          * since we need to update the PC anyways.
 308          */
 309         regs->pc = regs->rets;
 310 }
 311
 312 static inline
 313 int in_mem(unsigned long addr, unsigned long size,
 314            unsigned long start, unsigned long end)
 315 {
 316         return addr >= start && addr + size <= end;
 317 }
 318 static inline
 319 int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
 320                      unsigned long const_addr, unsigned long const_size)
 321 {
 322         return const_size &&
 323                in_mem(addr, size, const_addr + off, const_addr + const_size);
 324 }
 325 static inline
 326 int in_mem_const(unsigned long addr, unsigned long size,
 327                  unsigned long const_addr, unsigned long const_size)
 328 {
 329         return in_mem_const_off(addr, size, 0, const_addr, const_size);
 330 }
 331 #define ASYNC_ENABLED(bnum, bctlnum) \
 332 ({ \
 333         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? 0 : \
 334         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? 0 : \
 335         1; \
 336 })
 337 /*
 338  * We can't read EBIU banks that aren't enabled or we end up hanging
 339  * on the access to the async space.  Make sure we validate accesses
 340  * that cross async banks too.
 341  *      0 - found, but unusable
 342  *      1 - found & usable
 343  *      2 - not found
 344  */
 345 static
 346 int in_async(unsigned long addr, unsigned long size)
 347 {
 348         if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE) {
 349                 if (!ASYNC_ENABLED(0, 0))
 350                         return 0;
 351                 if (addr + size <= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE)
 352                         return 1;
 353                 size -= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE - addr;
 354                 addr = ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE;
 355         }
 356         if (addr >= ASYNC_BANK1_BASE && addr < ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE) {
 357                 if (!ASYNC_ENABLED(1, 0))
 358                         return 0;
 359                 if (addr + size <= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE)
 360                         return 1;
 361                 size -= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE - addr;
 362                 addr = ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE;
 363         }
 364         if (addr >= ASYNC_BANK2_BASE && addr < ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE) {
 365                 if (!ASYNC_ENABLED(2, 1))
 366                         return 0;
 367                 if (addr + size <= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE)
 368                         return 1;
 369                 size -= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE - addr;
 370                 addr = ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE;
 371         }
 372         if (addr >= ASYNC_BANK3_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
 373                 if (ASYNC_ENABLED(3, 1))
 374                         return 0;
 375                 if (addr + size <= ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE)
 376                         return 1;
 377                 return 0;
 378         }
 379
 380         /* not within async bounds */
 381         return 2;
 382 }
 383
 384 int bfin_mem_access_type(unsigned long addr, unsigned long size)
 385 {
 386         int cpu = raw_smp_processor_id();
 387
 388         /* Check that things do not wrap around */
 389         if (addr > ULONG_MAX - size)
 390                 return -EFAULT;
 391
 392         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 393                 return BFIN_MEM_ACCESS_CORE;
 394
 395         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 396                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 397         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 398                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 399         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 400                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 401         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 402                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 403 #ifdef COREB_L1_CODE_START
 404         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 405                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 406         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 407                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 408         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 409                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 410         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 411                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 412 #endif
 413         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 414                 return BFIN_MEM_ACCESS_CORE;
 415
 416         if (addr >= SYSMMR_BASE)
 417                 return BFIN_MEM_ACCESS_CORE_ONLY;
 418
 419         switch (in_async(addr, size)) {
 420         case 0: return -EFAULT;
 421         case 1: return BFIN_MEM_ACCESS_CORE;
 422         case 2: /* fall through */;
 423         }
 424
 425         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 426                 return BFIN_MEM_ACCESS_CORE;
 427         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 428                 return BFIN_MEM_ACCESS_DMA;
 429
 430         return -EFAULT;
 431 }
 432
 433 #if defined(CONFIG_ACCESS_CHECK)
 434 #ifdef CONFIG_ACCESS_OK_L1
 435 __attribute__((l1_text))
 436 #endif
 437 /* Return 1 if access to memory range is OK, 0 otherwise */
 438 int _access_ok(unsigned long addr, unsigned long size)
 439 {
 440         int aret;
 441
 442         if (size == 0)
 443                 return 1;
 444         /* Check that things do not wrap around */
 445         if (addr > ULONG_MAX - size)
 446                 return 0;
 447         if (segment_eq(get_fs(), KERNEL_DS))
 448                 return 1;
 449 #ifdef CONFIG_MTD_UCLINUX
 450         if (1)
 451 #else
 452         if (0)
 453 #endif
 454         {
 455                 if (in_mem(addr, size, memory_start, memory_end))
 456                         return 1;
 457                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 458                         return 1;
 459 # ifndef CONFIG_ROMFS_ON_MTD
 460                 if (0)
 461 # endif
 462                         /* For XIP, allow user space to use pointers within the ROMFS.  */
 463                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 464                                 return 1;
 465         } else {
 466                 if (in_mem(addr, size, memory_start, physical_mem_end))
 467                         return 1;
 468         }
 469
 470         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 471                 return 1;
 472
 473         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 474                 return 1;
 475         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 476                 return 1;
 477         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 478                 return 1;
 479         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 480                 return 1;
 481 #ifdef COREB_L1_CODE_START
 482         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 483                 return 1;
 484         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 485                 return 1;
 486         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 487                 return 1;
 488         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 489                 return 1;
 490 #endif
 491
 492 #ifndef CONFIG_EXCEPTION_L1_SCRATCH
 493         if (in_mem_const(addr, size, (unsigned long)l1_stack_base, l1_stack_len))
 494                 return 1;
 495 #endif
 496
 497         aret = in_async(addr, size);
 498         if (aret < 2)
 499                 return aret;
 500
 501         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 502                 return 1;
 503
 504         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 505                 return 1;
 506         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 507                 return 1;
 508
 509         return 0;
 510 }
 511 EXPORT_SYMBOL(_access_ok);
 512 #endif /* CONFIG_ACCESS_CHECK */