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