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  * This gets run with P1 containing the
 106  * function to call, and R1 containing
 107  * the "args".  Note P0 is clobbered on the way here.
 108  */
 109 void kernel_thread_helper(void);
 110 __asm__(".section .text\n"
 111         ".align 4\n"
 112         "_kernel_thread_helper:\n\t"
 113         "\tsp += -12;\n\t"
 114         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 115
 116 /*
 117  * Create a kernel thread.
 118  */
 119 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 120 {
 121         struct pt_regs regs;
 122
 123         memset(&regs, 0, sizeof(regs));
 124
 125         regs.r1 = (unsigned long)arg;
 126         regs.p1 = (unsigned long)fn;
 127         regs.pc = (unsigned long)kernel_thread_helper;
 128         regs.orig_p0 = -1;
 129         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 130            mode.  */
 131         regs.ipend = 0x8002;
 132         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 133         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 134                        NULL);
 135 }
 136 EXPORT_SYMBOL(kernel_thread);
 137
 138 /*
 139  * Do necessary setup to start up a newly executed thread.
 140  *
 141  * pass the data segment into user programs if it exists,
 142  * it can't hurt anything as far as I can tell
 143  */
 144 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 145 {
 146         regs->pc = new_ip;
 147         if (current->mm)
 148                 regs->p5 = current->mm->start_data;
 149 #ifndef CONFIG_SMP
 150         task_thread_info(current)->l1_task_info.stack_start =
 151                 (void *)current->mm->context.stack_start;
 152         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 153         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 154                sizeof(*L1_SCRATCH_TASK_INFO));
 155 #endif
 156         wrusp(new_sp);
 157 }
 158 EXPORT_SYMBOL_GPL(start_thread);
 159
 160 void flush_thread(void)
 161 {
 162 }
 163
 164 asmlinkage int bfin_vfork(struct pt_regs *regs)
 165 {
 166         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 167                        NULL);
 168 }
 169
 170 asmlinkage int bfin_clone(struct pt_regs *regs)
 171 {
 172         unsigned long clone_flags;
 173         unsigned long newsp;
 174
 175 #ifdef __ARCH_SYNC_CORE_DCACHE
 176         if (current->nr_cpus_allowed == num_possible_cpus())
 177                 set_cpus_allowed_ptr(current, cpumask_of(smp_processor_id()));
 178 #endif
 179
 180         /* syscall2 puts clone_flags in r0 and usp in r1 */
 181         clone_flags = regs->r0;
 182         newsp = regs->r1;
 183         if (!newsp)
 184                 newsp = rdusp();
 185         else
 186                 newsp -= 12;
 187         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 188 }
 189
 190 int
 191 copy_thread(unsigned long clone_flags,
 192             unsigned long usp, unsigned long topstk,
 193             struct task_struct *p, struct pt_regs *regs)
 194 {
 195         struct pt_regs *childregs;
 196
 197         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 198         *childregs = *regs;
 199         childregs->r0 = 0;
 200
 201         p->thread.usp = usp;
 202         p->thread.ksp = (unsigned long)childregs;
 203         p->thread.pc = (unsigned long)ret_from_fork;
 204
 205         return 0;
 206 }
 207
 208 /*
 209  * sys_execve() executes a new program.
 210  */
 211 asmlinkage int sys_execve(const char __user *name,
 212                           const char __user *const __user *argv,
 213                           const char __user *const __user *envp)
 214 {
 215         int error;
 216         char *filename;
 217         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 218
 219         filename = getname(name);
 220         error = PTR_ERR(filename);
 221         if (IS_ERR(filename))
 222                 return error;
 223         error = do_execve(filename, argv, envp, regs);
 224         putname(filename);
 225         return error;
 226 }
 227
 228 unsigned long get_wchan(struct task_struct *p)
 229 {
 230         unsigned long fp, pc;
 231         unsigned long stack_page;
 232         int count = 0;
 233         if (!p || p == current || p->state == TASK_RUNNING)
 234                 return 0;
 235
 236         stack_page = (unsigned long)p;
 237         fp = p->thread.usp;
 238         do {
 239                 if (fp < stack_page + sizeof(struct thread_info) ||
 240                     fp >= 8184 + stack_page)
 241                         return 0;
 242                 pc = ((unsigned long *)fp)[1];
 243                 if (!in_sched_functions(pc))
 244                         return pc;
 245                 fp = *(unsigned long *)fp;
 246         }
 247         while (count++ < 16);
 248         return 0;
 249 }
 250
 251 void finish_atomic_sections (struct pt_regs *regs)
 252 {
 253         int __user *up0 = (int __user *)regs->p0;
 254
 255         switch (regs->pc) {
 256         default:
 257                 /* not in middle of an atomic step, so resume like normal */
 258                 return;
 259
 260         case ATOMIC_XCHG32 + 2:
 261                 put_user(regs->r1, up0);
 262                 break;
 263
 264         case ATOMIC_CAS32 + 2:
 265         case ATOMIC_CAS32 + 4:
 266                 if (regs->r0 == regs->r1)
 267         case ATOMIC_CAS32 + 6:
 268                         put_user(regs->r2, up0);
 269                 break;
 270
 271         case ATOMIC_ADD32 + 2:
 272                 regs->r0 = regs->r1 + regs->r0;
 273                 /* fall through */
 274         case ATOMIC_ADD32 + 4:
 275                 put_user(regs->r0, up0);
 276                 break;
 277
 278         case ATOMIC_SUB32 + 2:
 279                 regs->r0 = regs->r1 - regs->r0;
 280                 /* fall through */
 281         case ATOMIC_SUB32 + 4:
 282                 put_user(regs->r0, up0);
 283                 break;
 284
 285         case ATOMIC_IOR32 + 2:
 286                 regs->r0 = regs->r1 | regs->r0;
 287                 /* fall through */
 288         case ATOMIC_IOR32 + 4:
 289                 put_user(regs->r0, up0);
 290                 break;
 291
 292         case ATOMIC_AND32 + 2:
 293                 regs->r0 = regs->r1 & regs->r0;
 294                 /* fall through */
 295         case ATOMIC_AND32 + 4:
 296                 put_user(regs->r0, up0);
 297                 break;
 298
 299         case ATOMIC_XOR32 + 2:
 300                 regs->r0 = regs->r1 ^ regs->r0;
 301                 /* fall through */
 302         case ATOMIC_XOR32 + 4:
 303                 put_user(regs->r0, up0);
 304                 break;
 305         }
 306
 307         /*
 308          * We've finished the atomic section, and the only thing left for
 309          * userspace is to do a RTS, so we might as well handle that too
 310          * since we need to update the PC anyways.
 311          */
 312         regs->pc = regs->rets;
 313 }
 314
 315 static inline
 316 int in_mem(unsigned long addr, unsigned long size,
 317            unsigned long start, unsigned long end)
 318 {
 319         return addr >= start && addr + size <= end;
 320 }
 321 static inline
 322 int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
 323                      unsigned long const_addr, unsigned long const_size)
 324 {
 325         return const_size &&
 326                in_mem(addr, size, const_addr + off, const_addr + const_size);
 327 }
 328 static inline
 329 int in_mem_const(unsigned long addr, unsigned long size,
 330                  unsigned long const_addr, unsigned long const_size)
 331 {
 332         return in_mem_const_off(addr, size, 0, const_addr, const_size);
 333 }
 334 #ifdef CONFIG_BF60x
 335 #define ASYNC_ENABLED(bnum, bctlnum)    1
 336 #else
 337 #define ASYNC_ENABLED(bnum, bctlnum) \
 338 ({ \
 339         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? 0 : \
 340         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? 0 : \
 341         1; \
 342 })
 343 #endif
 344 /*
 345  * We can't read EBIU banks that aren't enabled or we end up hanging
 346  * on the access to the async space.  Make sure we validate accesses
 347  * that cross async banks too.
 348  *      0 - found, but unusable
 349  *      1 - found & usable
 350  *      2 - not found
 351  */
 352 static
 353 int in_async(unsigned long addr, unsigned long size)
 354 {
 355         if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE) {
 356                 if (!ASYNC_ENABLED(0, 0))
 357                         return 0;
 358                 if (addr + size <= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE)
 359                         return 1;
 360                 size -= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE - addr;
 361                 addr = ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE;
 362         }
 363         if (addr >= ASYNC_BANK1_BASE && addr < ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE) {
 364                 if (!ASYNC_ENABLED(1, 0))
 365                         return 0;
 366                 if (addr + size <= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE)
 367                         return 1;
 368                 size -= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE - addr;
 369                 addr = ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE;
 370         }
 371         if (addr >= ASYNC_BANK2_BASE && addr < ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE) {
 372                 if (!ASYNC_ENABLED(2, 1))
 373                         return 0;
 374                 if (addr + size <= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE)
 375                         return 1;
 376                 size -= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE - addr;
 377                 addr = ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE;
 378         }
 379         if (addr >= ASYNC_BANK3_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
 380                 if (ASYNC_ENABLED(3, 1))
 381                         return 0;
 382                 if (addr + size <= ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE)
 383                         return 1;
 384                 return 0;
 385         }
 386
 387         /* not within async bounds */
 388         return 2;
 389 }
 390
 391 int bfin_mem_access_type(unsigned long addr, unsigned long size)
 392 {
 393         int cpu = raw_smp_processor_id();
 394
 395         /* Check that things do not wrap around */
 396         if (addr > ULONG_MAX - size)
 397                 return -EFAULT;
 398
 399         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 400                 return BFIN_MEM_ACCESS_CORE;
 401
 402         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 403                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 404         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 405                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 406         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 407                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 408         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 409                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 410 #ifdef COREB_L1_CODE_START
 411         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 412                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 413         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 414                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 415         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 416                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 417         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 418                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 419 #endif
 420         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 421                 return BFIN_MEM_ACCESS_CORE;
 422
 423         if (addr >= SYSMMR_BASE)
 424                 return BFIN_MEM_ACCESS_CORE_ONLY;
 425
 426         switch (in_async(addr, size)) {
 427         case 0: return -EFAULT;
 428         case 1: return BFIN_MEM_ACCESS_CORE;
 429         case 2: /* fall through */;
 430         }
 431
 432         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 433                 return BFIN_MEM_ACCESS_CORE;
 434         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 435                 return BFIN_MEM_ACCESS_DMA;
 436
 437         return -EFAULT;
 438 }
 439
 440 #if defined(CONFIG_ACCESS_CHECK)
 441 #ifdef CONFIG_ACCESS_OK_L1
 442 __attribute__((l1_text))
 443 #endif
 444 /* Return 1 if access to memory range is OK, 0 otherwise */
 445 int _access_ok(unsigned long addr, unsigned long size)
 446 {
 447         int aret;
 448
 449         if (size == 0)
 450                 return 1;
 451         /* Check that things do not wrap around */
 452         if (addr > ULONG_MAX - size)
 453                 return 0;
 454         if (segment_eq(get_fs(), KERNEL_DS))
 455                 return 1;
 456 #ifdef CONFIG_MTD_UCLINUX
 457         if (1)
 458 #else
 459         if (0)
 460 #endif
 461         {
 462                 if (in_mem(addr, size, memory_start, memory_end))
 463                         return 1;
 464                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 465                         return 1;
 466 # ifndef CONFIG_ROMFS_ON_MTD
 467                 if (0)
 468 # endif
 469                         /* For XIP, allow user space to use pointers within the ROMFS.  */
 470                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 471                                 return 1;
 472         } else {
 473                 if (in_mem(addr, size, memory_start, physical_mem_end))
 474                         return 1;
 475         }
 476
 477         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 478                 return 1;
 479
 480         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 481                 return 1;
 482         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 483                 return 1;
 484         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 485                 return 1;
 486         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 487                 return 1;
 488 #ifdef COREB_L1_CODE_START
 489         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 490                 return 1;
 491         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 492                 return 1;
 493         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 494                 return 1;
 495         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 496                 return 1;
 497 #endif
 498
 499 #ifndef CONFIG_EXCEPTION_L1_SCRATCH
 500         if (in_mem_const(addr, size, (unsigned long)l1_stack_base, l1_stack_len))
 501                 return 1;
 502 #endif
 503
 504         aret = in_async(addr, size);
 505         if (aret < 2)
 506                 return aret;
 507
 508         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 509                 return 1;
 510
 511         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 512                 return 1;
 513         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 514                 return 1;
 515
 516         return 0;
 517 }
 518 EXPORT_SYMBOL(_access_ok);
 519 #endif /* CONFIG_ACCESS_CHECK */