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/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         local_irq_disable_hw();
  68         if (!need_resched())
  69                 idle_with_irq_disabled();
  70
  71         local_irq_enable_hw();
  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 /* Fill in the fpu structure for a core dump.  */
 102
 103 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 104 {
 105         return 1;
 106 }
 107
 108 /*
 109  * This gets run with P1 containing the
 110  * function to call, and R1 containing
 111  * the "args".  Note P0 is clobbered on the way here.
 112  */
 113 void kernel_thread_helper(void);
 114 __asm__(".section .text\n"
 115         ".align 4\n"
 116         "_kernel_thread_helper:\n\t"
 117         "\tsp += -12;\n\t"
 118         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 119
 120 /*
 121  * Create a kernel thread.
 122  */
 123 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 124 {
 125         struct pt_regs regs;
 126
 127         memset(&regs, 0, sizeof(regs));
 128
 129         regs.r1 = (unsigned long)arg;
 130         regs.p1 = (unsigned long)fn;
 131         regs.pc = (unsigned long)kernel_thread_helper;
 132         regs.orig_p0 = -1;
 133         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 134            mode.  */
 135         regs.ipend = 0x8002;
 136         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 137         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 138                        NULL);
 139 }
 140 EXPORT_SYMBOL(kernel_thread);
 141
 142 /*
 143  * Do necessary setup to start up a newly executed thread.
 144  *
 145  * pass the data segment into user programs if it exists,
 146  * it can't hurt anything as far as I can tell
 147  */
 148 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 149 {
 150         set_fs(USER_DS);
 151         regs->pc = new_ip;
 152         if (current->mm)
 153                 regs->p5 = current->mm->start_data;
 154 #ifndef CONFIG_SMP
 155         task_thread_info(current)->l1_task_info.stack_start =
 156                 (void *)current->mm->context.stack_start;
 157         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 158         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 159                sizeof(*L1_SCRATCH_TASK_INFO));
 160 #endif
 161         wrusp(new_sp);
 162 }
 163 EXPORT_SYMBOL_GPL(start_thread);
 164
 165 void flush_thread(void)
 166 {
 167 }
 168
 169 asmlinkage int bfin_vfork(struct pt_regs *regs)
 170 {
 171         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 172                        NULL);
 173 }
 174
 175 asmlinkage int bfin_clone(struct pt_regs *regs)
 176 {
 177         unsigned long clone_flags;
 178         unsigned long newsp;
 179
 180 #ifdef __ARCH_SYNC_CORE_DCACHE
 181         if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
 182                 current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
 183                 current->rt.nr_cpus_allowed = 1;
 184         }
 185 #endif
 186
 187         /* syscall2 puts clone_flags in r0 and usp in r1 */
 188         clone_flags = regs->r0;
 189         newsp = regs->r1;
 190         if (!newsp)
 191                 newsp = rdusp();
 192         else
 193                 newsp -= 12;
 194         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 195 }
 196
 197 int
 198 copy_thread(unsigned long clone_flags,
 199             unsigned long usp, unsigned long topstk,
 200             struct task_struct *p, struct pt_regs *regs)
 201 {
 202         struct pt_regs *childregs;
 203
 204         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 205         *childregs = *regs;
 206         childregs->r0 = 0;
 207
 208         p->thread.usp = usp;
 209         p->thread.ksp = (unsigned long)childregs;
 210         p->thread.pc = (unsigned long)ret_from_fork;
 211
 212         return 0;
 213 }
 214
 215 /*
 216  * sys_execve() executes a new program.
 217  */
 218 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 219 {
 220         int error;
 221         char *filename;
 222         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 223
 224         filename = getname(name);
 225         error = PTR_ERR(filename);
 226         if (IS_ERR(filename))
 227                 return error;
 228         error = do_execve(filename, argv, envp, regs);
 229         putname(filename);
 230         return error;
 231 }
 232
 233 unsigned long get_wchan(struct task_struct *p)
 234 {
 235         unsigned long fp, pc;
 236         unsigned long stack_page;
 237         int count = 0;
 238         if (!p || p == current || p->state == TASK_RUNNING)
 239                 return 0;
 240
 241         stack_page = (unsigned long)p;
 242         fp = p->thread.usp;
 243         do {
 244                 if (fp < stack_page + sizeof(struct thread_info) ||
 245                     fp >= 8184 + stack_page)
 246                         return 0;
 247                 pc = ((unsigned long *)fp)[1];
 248                 if (!in_sched_functions(pc))
 249                         return pc;
 250                 fp = *(unsigned long *)fp;
 251         }
 252         while (count++ < 16);
 253         return 0;
 254 }
 255
 256 void finish_atomic_sections (struct pt_regs *regs)
 257 {
 258         int __user *up0 = (int __user *)regs->p0;
 259
 260         switch (regs->pc) {
 261         case ATOMIC_XCHG32 + 2:
 262                 put_user(regs->r1, up0);
 263                 regs->pc = ATOMIC_XCHG32 + 4;
 264                 break;
 265
 266         case ATOMIC_CAS32 + 2:
 267         case ATOMIC_CAS32 + 4:
 268                 if (regs->r0 == regs->r1)
 269         case ATOMIC_CAS32 + 6:
 270                         put_user(regs->r2, up0);
 271                 regs->pc = ATOMIC_CAS32 + 8;
 272                 break;
 273
 274         case ATOMIC_ADD32 + 2:
 275                 regs->r0 = regs->r1 + regs->r0;
 276                 /* fall through */
 277         case ATOMIC_ADD32 + 4:
 278                 put_user(regs->r0, up0);
 279                 regs->pc = ATOMIC_ADD32 + 6;
 280                 break;
 281
 282         case ATOMIC_SUB32 + 2:
 283                 regs->r0 = regs->r1 - regs->r0;
 284                 /* fall through */
 285         case ATOMIC_SUB32 + 4:
 286                 put_user(regs->r0, up0);
 287                 regs->pc = ATOMIC_SUB32 + 6;
 288                 break;
 289
 290         case ATOMIC_IOR32 + 2:
 291                 regs->r0 = regs->r1 | regs->r0;
 292                 /* fall through */
 293         case ATOMIC_IOR32 + 4:
 294                 put_user(regs->r0, up0);
 295                 regs->pc = ATOMIC_IOR32 + 6;
 296                 break;
 297
 298         case ATOMIC_AND32 + 2:
 299                 regs->r0 = regs->r1 & regs->r0;
 300                 /* fall through */
 301         case ATOMIC_AND32 + 4:
 302                 put_user(regs->r0, up0);
 303                 regs->pc = ATOMIC_AND32 + 6;
 304                 break;
 305
 306         case ATOMIC_XOR32 + 2:
 307                 regs->r0 = regs->r1 ^ regs->r0;
 308                 /* fall through */
 309         case ATOMIC_XOR32 + 4:
 310                 put_user(regs->r0, up0);
 311                 regs->pc = ATOMIC_XOR32 + 6;
 312                 break;
 313         }
 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 IN_ASYNC(bnum, bctlnum) \
 336 ({ \
 337         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? -EFAULT : \
 338         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? -EFAULT : \
 339         BFIN_MEM_ACCESS_CORE; \
 340 })
 341
 342 int bfin_mem_access_type(unsigned long addr, unsigned long size)
 343 {
 344         int cpu = raw_smp_processor_id();
 345
 346         /* Check that things do not wrap around */
 347         if (addr > ULONG_MAX - size)
 348                 return -EFAULT;
 349
 350         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 351                 return BFIN_MEM_ACCESS_CORE;
 352
 353         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 354                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 355         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 356                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 357         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 358                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 359         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 360                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 361 #ifdef COREB_L1_CODE_START
 362         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 363                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 364         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 365                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 366         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 367                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 368         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 369                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 370 #endif
 371         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 372                 return BFIN_MEM_ACCESS_CORE;
 373
 374         if (addr >= SYSMMR_BASE)
 375                 return BFIN_MEM_ACCESS_CORE_ONLY;
 376
 377         /* We can't read EBIU banks that aren't enabled or we end up hanging
 378          * on the access to the async space.
 379          */
 380         if (in_mem_const(addr, size, ASYNC_BANK0_BASE, ASYNC_BANK0_SIZE))
 381                 return IN_ASYNC(0, 0);
 382         if (in_mem_const(addr, size, ASYNC_BANK1_BASE, ASYNC_BANK1_SIZE))
 383                 return IN_ASYNC(1, 0);
 384         if (in_mem_const(addr, size, ASYNC_BANK2_BASE, ASYNC_BANK2_SIZE))
 385                 return IN_ASYNC(2, 1);
 386         if (in_mem_const(addr, size, ASYNC_BANK3_BASE, ASYNC_BANK3_SIZE))
 387                 return IN_ASYNC(3, 1);
 388
 389         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 390                 return BFIN_MEM_ACCESS_CORE;
 391         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 392                 return BFIN_MEM_ACCESS_DMA;
 393
 394         return -EFAULT;
 395 }
 396
 397 #if defined(CONFIG_ACCESS_CHECK)
 398 #ifdef CONFIG_ACCESS_OK_L1
 399 __attribute__((l1_text))
 400 #endif
 401 /* Return 1 if access to memory range is OK, 0 otherwise */
 402 int _access_ok(unsigned long addr, unsigned long size)
 403 {
 404         if (size == 0)
 405                 return 1;
 406         /* Check that things do not wrap around */
 407         if (addr > ULONG_MAX - size)
 408                 return 0;
 409         if (segment_eq(get_fs(), KERNEL_DS))
 410                 return 1;
 411 #ifdef CONFIG_MTD_UCLINUX
 412         if (1)
 413 #else
 414         if (0)
 415 #endif
 416         {
 417                 if (in_mem(addr, size, memory_start, memory_end))
 418                         return 1;
 419                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 420                         return 1;
 421 # ifndef CONFIG_ROMFS_ON_MTD
 422                 if (0)
 423 # endif
 424                         /* For XIP, allow user space to use pointers within the ROMFS.  */
 425                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 426                                 return 1;
 427         } else {
 428                 if (in_mem(addr, size, memory_start, physical_mem_end))
 429                         return 1;
 430         }
 431
 432         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 433                 return 1;
 434
 435         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 436                 return 1;
 437         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 438                 return 1;
 439         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 440                 return 1;
 441         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 442                 return 1;
 443 #ifdef COREB_L1_CODE_START
 444         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 445                 return 1;
 446         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 447                 return 1;
 448         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 449                 return 1;
 450         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 451                 return 1;
 452 #endif
 453         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 454                 return 1;
 455
 456         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 457                 return 1;
 458         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 459                 return 1;
 460
 461         return 0;
 462 }
 463 EXPORT_SYMBOL(_access_ok);
 464 #endif /* CONFIG_ACCESS_CHECK */