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/smp_lock.h>
  11 #include <linux/unistd.h>
  12 #include <linux/user.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/slab.h>
  15 #include <linux/sched.h>
  16 #include <linux/tick.h>
  17 #include <linux/fs.h>
  18 #include <linux/err.h>
  19
  20 #include <asm/blackfin.h>
  21 #include <asm/fixed_code.h>
  22 #include <asm/mem_map.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_stop_sched_tick(1);
  93                 while (!need_resched())
  94                         idle();
  95                 tick_nohz_restart_sched_tick();
  96                 preempt_enable_no_resched();
  97                 schedule();
  98                 preempt_disable();
  99         }
 100 }
 101
 102 /*
 103  * This gets run with P1 containing the
 104  * function to call, and R1 containing
 105  * the "args".  Note P0 is clobbered on the way here.
 106  */
 107 void kernel_thread_helper(void);
 108 __asm__(".section .text\n"
 109         ".align 4\n"
 110         "_kernel_thread_helper:\n\t"
 111         "\tsp += -12;\n\t"
 112         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 113
 114 /*
 115  * Create a kernel thread.
 116  */
 117 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 118 {
 119         struct pt_regs regs;
 120
 121         memset(&regs, 0, sizeof(regs));
 122
 123         regs.r1 = (unsigned long)arg;
 124         regs.p1 = (unsigned long)fn;
 125         regs.pc = (unsigned long)kernel_thread_helper;
 126         regs.orig_p0 = -1;
 127         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 128            mode.  */
 129         regs.ipend = 0x8002;
 130         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 131         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 132                        NULL);
 133 }
 134 EXPORT_SYMBOL(kernel_thread);
 135
 136 /*
 137  * Do necessary setup to start up a newly executed thread.
 138  *
 139  * pass the data segment into user programs if it exists,
 140  * it can't hurt anything as far as I can tell
 141  */
 142 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 143 {
 144         set_fs(USER_DS);
 145         regs->pc = new_ip;
 146         if (current->mm)
 147                 regs->p5 = current->mm->start_data;
 148 #ifndef CONFIG_SMP
 149         task_thread_info(current)->l1_task_info.stack_start =
 150                 (void *)current->mm->context.stack_start;
 151         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 152         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 153                sizeof(*L1_SCRATCH_TASK_INFO));
 154 #endif
 155         wrusp(new_sp);
 156 }
 157 EXPORT_SYMBOL_GPL(start_thread);
 158
 159 void flush_thread(void)
 160 {
 161 }
 162
 163 asmlinkage int bfin_vfork(struct pt_regs *regs)
 164 {
 165         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 166                        NULL);
 167 }
 168
 169 asmlinkage int bfin_clone(struct pt_regs *regs)
 170 {
 171         unsigned long clone_flags;
 172         unsigned long newsp;
 173
 174 #ifdef __ARCH_SYNC_CORE_DCACHE
 175         if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
 176                 current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
 177                 current->rt.nr_cpus_allowed = 1;
 178         }
 179 #endif
 180
 181         /* syscall2 puts clone_flags in r0 and usp in r1 */
 182         clone_flags = regs->r0;
 183         newsp = regs->r1;
 184         if (!newsp)
 185                 newsp = rdusp();
 186         else
 187                 newsp -= 12;
 188         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 189 }
 190
 191 int
 192 copy_thread(unsigned long clone_flags,
 193             unsigned long usp, unsigned long topstk,
 194             struct task_struct *p, struct pt_regs *regs)
 195 {
 196         struct pt_regs *childregs;
 197
 198         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 199         *childregs = *regs;
 200         childregs->r0 = 0;
 201
 202         p->thread.usp = usp;
 203         p->thread.ksp = (unsigned long)childregs;
 204         p->thread.pc = (unsigned long)ret_from_fork;
 205
 206         return 0;
 207 }
 208
 209 /*
 210  * sys_execve() executes a new program.
 211  */
 212 asmlinkage int sys_execve(const char __user *name,
 213                           const char __user *const __user *argv,
 214                           const char __user *const __user *envp)
 215 {
 216         int error;
 217         char *filename;
 218         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 219
 220         filename = getname(name);
 221         error = PTR_ERR(filename);
 222         if (IS_ERR(filename))
 223                 return error;
 224         error = do_execve(filename, argv, envp, regs);
 225         putname(filename);
 226         return error;
 227 }
 228
 229 unsigned long get_wchan(struct task_struct *p)
 230 {
 231         unsigned long fp, pc;
 232         unsigned long stack_page;
 233         int count = 0;
 234         if (!p || p == current || p->state == TASK_RUNNING)
 235                 return 0;
 236
 237         stack_page = (unsigned long)p;
 238         fp = p->thread.usp;
 239         do {
 240                 if (fp < stack_page + sizeof(struct thread_info) ||
 241                     fp >= 8184 + stack_page)
 242                         return 0;
 243                 pc = ((unsigned long *)fp)[1];
 244                 if (!in_sched_functions(pc))
 245                         return pc;
 246                 fp = *(unsigned long *)fp;
 247         }
 248         while (count++ < 16);
 249         return 0;
 250 }
 251
 252 void finish_atomic_sections (struct pt_regs *regs)
 253 {
 254         int __user *up0 = (int __user *)regs->p0;
 255
 256         switch (regs->pc) {
 257         default:
 258                 /* not in middle of an atomic step, so resume like normal */
 259                 return;
 260
 261         case ATOMIC_XCHG32 + 2:
 262                 put_user(regs->r1, up0);
 263                 break;
 264
 265         case ATOMIC_CAS32 + 2:
 266         case ATOMIC_CAS32 + 4:
 267                 if (regs->r0 == regs->r1)
 268         case ATOMIC_CAS32 + 6:
 269                         put_user(regs->r2, up0);
 270                 break;
 271
 272         case ATOMIC_ADD32 + 2:
 273                 regs->r0 = regs->r1 + regs->r0;
 274                 /* fall through */
 275         case ATOMIC_ADD32 + 4:
 276                 put_user(regs->r0, up0);
 277                 break;
 278
 279         case ATOMIC_SUB32 + 2:
 280                 regs->r0 = regs->r1 - regs->r0;
 281                 /* fall through */
 282         case ATOMIC_SUB32 + 4:
 283                 put_user(regs->r0, up0);
 284                 break;
 285
 286         case ATOMIC_IOR32 + 2:
 287                 regs->r0 = regs->r1 | regs->r0;
 288                 /* fall through */
 289         case ATOMIC_IOR32 + 4:
 290                 put_user(regs->r0, up0);
 291                 break;
 292
 293         case ATOMIC_AND32 + 2:
 294                 regs->r0 = regs->r1 & regs->r0;
 295                 /* fall through */
 296         case ATOMIC_AND32 + 4:
 297                 put_user(regs->r0, up0);
 298                 break;
 299
 300         case ATOMIC_XOR32 + 2:
 301                 regs->r0 = regs->r1 ^ regs->r0;
 302                 /* fall through */
 303         case ATOMIC_XOR32 + 4:
 304                 put_user(regs->r0, up0);
 305                 break;
 306         }
 307
 308         /*
 309          * We've finished the atomic section, and the only thing left for
 310          * userspace is to do a RTS, so we might as well handle that too
 311          * since we need to update the PC anyways.
 312          */
 313         regs->pc = regs->rets;
 314 }
 315
 316 static inline
 317 int in_mem(unsigned long addr, unsigned long size,
 318            unsigned long start, unsigned long end)
 319 {
 320         return addr >= start && addr + size <= end;
 321 }
 322 static inline
 323 int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
 324                      unsigned long const_addr, unsigned long const_size)
 325 {
 326         return const_size &&
 327                in_mem(addr, size, const_addr + off, const_addr + const_size);
 328 }
 329 static inline
 330 int in_mem_const(unsigned long addr, unsigned long size,
 331                  unsigned long const_addr, unsigned long const_size)
 332 {
 333         return in_mem_const_off(addr, size, 0, const_addr, const_size);
 334 }
 335 #define ASYNC_ENABLED(bnum, bctlnum) \
 336 ({ \
 337         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? 0 : \
 338         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? 0 : \
 339         1; \
 340 })
 341 /*
 342  * We can't read EBIU banks that aren't enabled or we end up hanging
 343  * on the access to the async space.  Make sure we validate accesses
 344  * that cross async banks too.
 345  *      0 - found, but unusable
 346  *      1 - found & usable
 347  *      2 - not found
 348  */
 349 static
 350 int in_async(unsigned long addr, unsigned long size)
 351 {
 352         if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE) {
 353                 if (!ASYNC_ENABLED(0, 0))
 354                         return 0;
 355                 if (addr + size <= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE)
 356                         return 1;
 357                 size -= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE - addr;
 358                 addr = ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE;
 359         }
 360         if (addr >= ASYNC_BANK1_BASE && addr < ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE) {
 361                 if (!ASYNC_ENABLED(1, 0))
 362                         return 0;
 363                 if (addr + size <= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE)
 364                         return 1;
 365                 size -= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE - addr;
 366                 addr = ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE;
 367         }
 368         if (addr >= ASYNC_BANK2_BASE && addr < ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE) {
 369                 if (!ASYNC_ENABLED(2, 1))
 370                         return 0;
 371                 if (addr + size <= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE)
 372                         return 1;
 373                 size -= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE - addr;
 374                 addr = ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE;
 375         }
 376         if (addr >= ASYNC_BANK3_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
 377                 if (ASYNC_ENABLED(3, 1))
 378                         return 0;
 379                 if (addr + size <= ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE)
 380                         return 1;
 381                 return 0;
 382         }
 383
 384         /* not within async bounds */
 385         return 2;
 386 }
 387
 388 int bfin_mem_access_type(unsigned long addr, unsigned long size)
 389 {
 390         int cpu = raw_smp_processor_id();
 391
 392         /* Check that things do not wrap around */
 393         if (addr > ULONG_MAX - size)
 394                 return -EFAULT;
 395
 396         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 397                 return BFIN_MEM_ACCESS_CORE;
 398
 399         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 400                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 401         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 402                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 403         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 404                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 405         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 406                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 407 #ifdef COREB_L1_CODE_START
 408         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 409                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 410         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 411                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 412         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 413                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 414         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 415                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 416 #endif
 417         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 418                 return BFIN_MEM_ACCESS_CORE;
 419
 420         if (addr >= SYSMMR_BASE)
 421                 return BFIN_MEM_ACCESS_CORE_ONLY;
 422
 423         switch (in_async(addr, size)) {
 424         case 0: return -EFAULT;
 425         case 1: return BFIN_MEM_ACCESS_CORE;
 426         case 2: /* fall through */;
 427         }
 428
 429         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 430                 return BFIN_MEM_ACCESS_CORE;
 431         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 432                 return BFIN_MEM_ACCESS_DMA;
 433
 434         return -EFAULT;
 435 }
 436
 437 #if defined(CONFIG_ACCESS_CHECK)
 438 #ifdef CONFIG_ACCESS_OK_L1
 439 __attribute__((l1_text))
 440 #endif
 441 /* Return 1 if access to memory range is OK, 0 otherwise */
 442 int _access_ok(unsigned long addr, unsigned long size)
 443 {
 444         int aret;
 445
 446         if (size == 0)
 447                 return 1;
 448         /* Check that things do not wrap around */
 449         if (addr > ULONG_MAX - size)
 450                 return 0;
 451         if (segment_eq(get_fs(), KERNEL_DS))
 452                 return 1;
 453 #ifdef CONFIG_MTD_UCLINUX
 454         if (1)
 455 #else
 456         if (0)
 457 #endif
 458         {
 459                 if (in_mem(addr, size, memory_start, memory_end))
 460                         return 1;
 461                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 462                         return 1;
 463 # ifndef CONFIG_ROMFS_ON_MTD
 464                 if (0)
 465 # endif
 466                         /* For XIP, allow user space to use pointers within the ROMFS.  */
 467                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 468                                 return 1;
 469         } else {
 470                 if (in_mem(addr, size, memory_start, physical_mem_end))
 471                         return 1;
 472         }
 473
 474         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 475                 return 1;
 476
 477         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 478                 return 1;
 479         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 480                 return 1;
 481         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 482                 return 1;
 483         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 484                 return 1;
 485 #ifdef COREB_L1_CODE_START
 486         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 487                 return 1;
 488         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 489                 return 1;
 490         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 491                 return 1;
 492         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 493                 return 1;
 494 #endif
 495
 496 #ifndef CONFIG_EXCEPTION_L1_SCRATCH
 497         if (in_mem_const(addr, size, (unsigned long)l1_stack_base, l1_stack_len))
 498                 return 1;
 499 #endif
 500
 501         aret = in_async(addr, size);
 502         if (aret < 2)
 503                 return aret;
 504
 505         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 506                 return 1;
 507
 508         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 509                 return 1;
 510         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 511                 return 1;
 512
 513         return 0;
 514 }
 515 EXPORT_SYMBOL(_access_ok);
 516 #endif /* CONFIG_ACCESS_CHECK */