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   1 /*
   2  * File:         arch/blackfin/kernel/process.c
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:  Blackfin architecture-dependent process handling.
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/module.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/unistd.h>
  33 #include <linux/user.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/sched.h>
  36 #include <linux/tick.h>
  37 #include <linux/fs.h>
  38 #include <linux/err.h>
  39
  40 #include <asm/blackfin.h>
  41 #include <asm/fixed_code.h>
  42 #include <asm/mem_map.h>
  43
  44 asmlinkage void ret_from_fork(void);
  45
  46 /* Points to the SDRAM backup memory for the stack that is currently in
  47  * L1 scratchpad memory.
  48  */
  49 void *current_l1_stack_save;
  50
  51 /* The number of tasks currently using a L1 stack area.  The SRAM is
  52  * allocated/deallocated whenever this changes from/to zero.
  53  */
  54 int nr_l1stack_tasks;
  55
  56 /* Start and length of the area in L1 scratchpad memory which we've allocated
  57  * for process stacks.
  58  */
  59 void *l1_stack_base;
  60 unsigned long l1_stack_len;
  61
  62 /*
  63  * Powermanagement idle function, if any..
  64  */
  65 void (*pm_idle)(void) = NULL;
  66 EXPORT_SYMBOL(pm_idle);
  67
  68 void (*pm_power_off)(void) = NULL;
  69 EXPORT_SYMBOL(pm_power_off);
  70
  71 /*
  72  * The idle loop on BFIN
  73  */
  74 #ifdef CONFIG_IDLE_L1
  75 static void default_idle(void)__attribute__((l1_text));
  76 void cpu_idle(void)__attribute__((l1_text));
  77 #endif
  78
  79 /*
  80  * This is our default idle handler.  We need to disable
  81  * interrupts here to ensure we don't miss a wakeup call.
  82  */
  83 static void default_idle(void)
  84 {
  85 #ifdef CONFIG_IPIPE
  86         ipipe_suspend_domain();
  87 #endif
  88         local_irq_disable_hw();
  89         if (!need_resched())
  90                 idle_with_irq_disabled();
  91
  92         local_irq_enable_hw();
  93 }
  94
  95 /*
  96  * The idle thread.  We try to conserve power, while trying to keep
  97  * overall latency low.  The architecture specific idle is passed
  98  * a value to indicate the level of "idleness" of the system.
  99  */
 100 void cpu_idle(void)
 101 {
 102         /* endless idle loop with no priority at all */
 103         while (1) {
 104                 void (*idle)(void) = pm_idle;
 105
 106 #ifdef CONFIG_HOTPLUG_CPU
 107                 if (cpu_is_offline(smp_processor_id()))
 108                         cpu_die();
 109 #endif
 110                 if (!idle)
 111                         idle = default_idle;
 112                 tick_nohz_stop_sched_tick(1);
 113                 while (!need_resched())
 114                         idle();
 115                 tick_nohz_restart_sched_tick();
 116                 preempt_enable_no_resched();
 117                 schedule();
 118                 preempt_disable();
 119         }
 120 }
 121
 122 /* Fill in the fpu structure for a core dump.  */
 123
 124 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 125 {
 126         return 1;
 127 }
 128
 129 /*
 130  * This gets run with P1 containing the
 131  * function to call, and R1 containing
 132  * the "args".  Note P0 is clobbered on the way here.
 133  */
 134 void kernel_thread_helper(void);
 135 __asm__(".section .text\n"
 136         ".align 4\n"
 137         "_kernel_thread_helper:\n\t"
 138         "\tsp += -12;\n\t"
 139         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 140
 141 /*
 142  * Create a kernel thread.
 143  */
 144 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 145 {
 146         struct pt_regs regs;
 147
 148         memset(&regs, 0, sizeof(regs));
 149
 150         regs.r1 = (unsigned long)arg;
 151         regs.p1 = (unsigned long)fn;
 152         regs.pc = (unsigned long)kernel_thread_helper;
 153         regs.orig_p0 = -1;
 154         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 155            mode.  */
 156         regs.ipend = 0x8002;
 157         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 158         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 159                        NULL);
 160 }
 161 EXPORT_SYMBOL(kernel_thread);
 162
 163 /*
 164  * Do necessary setup to start up a newly executed thread.
 165  *
 166  * pass the data segment into user programs if it exists,
 167  * it can't hurt anything as far as I can tell
 168  */
 169 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 170 {
 171         set_fs(USER_DS);
 172         regs->pc = new_ip;
 173         if (current->mm)
 174                 regs->p5 = current->mm->start_data;
 175 #ifdef CONFIG_SMP
 176         task_thread_info(current)->l1_task_info.stack_start =
 177                 (void *)current->mm->context.stack_start;
 178         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
 179         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
 180                sizeof(*L1_SCRATCH_TASK_INFO));
 181 #endif
 182         wrusp(new_sp);
 183 }
 184 EXPORT_SYMBOL_GPL(start_thread);
 185
 186 void flush_thread(void)
 187 {
 188 }
 189
 190 asmlinkage int bfin_vfork(struct pt_regs *regs)
 191 {
 192         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 193                        NULL);
 194 }
 195
 196 asmlinkage int bfin_clone(struct pt_regs *regs)
 197 {
 198         unsigned long clone_flags;
 199         unsigned long newsp;
 200
 201 #ifdef __ARCH_SYNC_CORE_DCACHE
 202         if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
 203                 current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
 204                 current->rt.nr_cpus_allowed = 1;
 205         }
 206 #endif
 207
 208         /* syscall2 puts clone_flags in r0 and usp in r1 */
 209         clone_flags = regs->r0;
 210         newsp = regs->r1;
 211         if (!newsp)
 212                 newsp = rdusp();
 213         else
 214                 newsp -= 12;
 215         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 216 }
 217
 218 int
 219 copy_thread(unsigned long clone_flags,
 220             unsigned long usp, unsigned long topstk,
 221             struct task_struct *p, struct pt_regs *regs)
 222 {
 223         struct pt_regs *childregs;
 224
 225         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 226         *childregs = *regs;
 227         childregs->r0 = 0;
 228
 229         p->thread.usp = usp;
 230         p->thread.ksp = (unsigned long)childregs;
 231         p->thread.pc = (unsigned long)ret_from_fork;
 232
 233         return 0;
 234 }
 235
 236 /*
 237  * sys_execve() executes a new program.
 238  */
 239
 240 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 241 {
 242         int error;
 243         char *filename;
 244         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 245
 246         lock_kernel();
 247         filename = getname(name);
 248         error = PTR_ERR(filename);
 249         if (IS_ERR(filename))
 250                 goto out;
 251         error = do_execve(filename, argv, envp, regs);
 252         putname(filename);
 253  out:
 254         unlock_kernel();
 255         return error;
 256 }
 257
 258 unsigned long get_wchan(struct task_struct *p)
 259 {
 260         unsigned long fp, pc;
 261         unsigned long stack_page;
 262         int count = 0;
 263         if (!p || p == current || p->state == TASK_RUNNING)
 264                 return 0;
 265
 266         stack_page = (unsigned long)p;
 267         fp = p->thread.usp;
 268         do {
 269                 if (fp < stack_page + sizeof(struct thread_info) ||
 270                     fp >= 8184 + stack_page)
 271                         return 0;
 272                 pc = ((unsigned long *)fp)[1];
 273                 if (!in_sched_functions(pc))
 274                         return pc;
 275                 fp = *(unsigned long *)fp;
 276         }
 277         while (count++ < 16);
 278         return 0;
 279 }
 280
 281 void finish_atomic_sections (struct pt_regs *regs)
 282 {
 283         int __user *up0 = (int __user *)regs->p0;
 284
 285         switch (regs->pc) {
 286         case ATOMIC_XCHG32 + 2:
 287                 put_user(regs->r1, up0);
 288                 regs->pc = ATOMIC_XCHG32 + 4;
 289                 break;
 290
 291         case ATOMIC_CAS32 + 2:
 292         case ATOMIC_CAS32 + 4:
 293                 if (regs->r0 == regs->r1)
 294         case ATOMIC_CAS32 + 6:
 295                         put_user(regs->r2, up0);
 296                 regs->pc = ATOMIC_CAS32 + 8;
 297                 break;
 298
 299         case ATOMIC_ADD32 + 2:
 300                 regs->r0 = regs->r1 + regs->r0;
 301                 /* fall through */
 302         case ATOMIC_ADD32 + 4:
 303                 put_user(regs->r0, up0);
 304                 regs->pc = ATOMIC_ADD32 + 6;
 305                 break;
 306
 307         case ATOMIC_SUB32 + 2:
 308                 regs->r0 = regs->r1 - regs->r0;
 309                 /* fall through */
 310         case ATOMIC_SUB32 + 4:
 311                 put_user(regs->r0, up0);
 312                 regs->pc = ATOMIC_SUB32 + 6;
 313                 break;
 314
 315         case ATOMIC_IOR32 + 2:
 316                 regs->r0 = regs->r1 | regs->r0;
 317                 /* fall through */
 318         case ATOMIC_IOR32 + 4:
 319                 put_user(regs->r0, up0);
 320                 regs->pc = ATOMIC_IOR32 + 6;
 321                 break;
 322
 323         case ATOMIC_AND32 + 2:
 324                 regs->r0 = regs->r1 & regs->r0;
 325                 /* fall through */
 326         case ATOMIC_AND32 + 4:
 327                 put_user(regs->r0, up0);
 328                 regs->pc = ATOMIC_AND32 + 6;
 329                 break;
 330
 331         case ATOMIC_XOR32 + 2:
 332                 regs->r0 = regs->r1 ^ regs->r0;
 333                 /* fall through */
 334         case ATOMIC_XOR32 + 4:
 335                 put_user(regs->r0, up0);
 336                 regs->pc = ATOMIC_XOR32 + 6;
 337                 break;
 338         }
 339 }
 340
 341 static inline
 342 int in_mem(unsigned long addr, unsigned long size,
 343            unsigned long start, unsigned long end)
 344 {
 345         return addr >= start && addr + size <= end;
 346 }
 347 static inline
 348 int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
 349                      unsigned long const_addr, unsigned long const_size)
 350 {
 351         return const_size &&
 352                in_mem(addr, size, const_addr + off, const_addr + const_size);
 353 }
 354 static inline
 355 int in_mem_const(unsigned long addr, unsigned long size,
 356                  unsigned long const_addr, unsigned long const_size)
 357 {
 358         return in_mem_const_off(addr, size, 0, const_addr, const_size);
 359 }
 360 #define IN_ASYNC(bnum, bctlnum) \
 361 ({ \
 362         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? -EFAULT : \
 363         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? -EFAULT : \
 364         BFIN_MEM_ACCESS_CORE; \
 365 })
 366
 367 int bfin_mem_access_type(unsigned long addr, unsigned long size)
 368 {
 369         int cpu = raw_smp_processor_id();
 370
 371         /* Check that things do not wrap around */
 372         if (addr > ULONG_MAX - size)
 373                 return -EFAULT;
 374
 375         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
 376                 return BFIN_MEM_ACCESS_CORE;
 377
 378         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 379                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 380         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 381                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 382         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
 383                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 384         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
 385                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 386 #ifdef COREB_L1_CODE_START
 387         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 388                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
 389         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 390                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
 391         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 392                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 393         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 394                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
 395 #endif
 396         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
 397                 return BFIN_MEM_ACCESS_CORE;
 398
 399         if (addr >= SYSMMR_BASE)
 400                 return BFIN_MEM_ACCESS_CORE_ONLY;
 401
 402         /* We can't read EBIU banks that aren't enabled or we end up hanging
 403          * on the access to the async space.
 404          */
 405         if (in_mem_const(addr, size, ASYNC_BANK0_BASE, ASYNC_BANK0_SIZE))
 406                 return IN_ASYNC(0, 0);
 407         if (in_mem_const(addr, size, ASYNC_BANK1_BASE, ASYNC_BANK1_SIZE))
 408                 return IN_ASYNC(1, 0);
 409         if (in_mem_const(addr, size, ASYNC_BANK2_BASE, ASYNC_BANK2_SIZE))
 410                 return IN_ASYNC(2, 1);
 411         if (in_mem_const(addr, size, ASYNC_BANK3_BASE, ASYNC_BANK3_SIZE))
 412                 return IN_ASYNC(3, 1);
 413
 414         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 415                 return BFIN_MEM_ACCESS_CORE;
 416         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 417                 return BFIN_MEM_ACCESS_DMA;
 418
 419         return -EFAULT;
 420 }
 421
 422 #if defined(CONFIG_ACCESS_CHECK)
 423 #ifdef CONFIG_ACCESS_OK_L1
 424 __attribute__((l1_text))
 425 #endif
 426 /* Return 1 if access to memory range is OK, 0 otherwise */
 427 int _access_ok(unsigned long addr, unsigned long size)
 428 {
 429         if (size == 0)
 430                 return 1;
 431         /* Check that things do not wrap around */
 432         if (addr > ULONG_MAX - size)
 433                 return 0;
 434         if (segment_eq(get_fs(), KERNEL_DS))
 435                 return 1;
 436 #ifdef CONFIG_MTD_UCLINUX
 437         if (1)
 438 #else
 439         if (0)
 440 #endif
 441         {
 442                 if (in_mem(addr, size, memory_start, memory_end))
 443                         return 1;
 444                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
 445                         return 1;
 446 # ifndef CONFIG_ROMFS_ON_MTD
 447                 if (0)
 448 # endif
 449                         /* For XIP, allow user space to use pointers within the ROMFS.  */
 450                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
 451                                 return 1;
 452         } else {
 453                 if (in_mem(addr, size, memory_start, physical_mem_end))
 454                         return 1;
 455         }
 456
 457         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
 458                 return 1;
 459
 460         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
 461                 return 1;
 462         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
 463                 return 1;
 464         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
 465                 return 1;
 466         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
 467                 return 1;
 468 #ifdef COREB_L1_CODE_START
 469         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
 470                 return 1;
 471         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
 472                 return 1;
 473         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
 474                 return 1;
 475         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
 476                 return 1;
 477 #endif
 478         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
 479                 return 1;
 480
 481         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
 482                 return 1;
 483         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
 484                 return 1;
 485
 486         return 0;
 487 }
 488 EXPORT_SYMBOL(_access_ok);
 489 #endif /* CONFIG_ACCESS_CHECK */