arch/avr32/kernel/process.c

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #include <linux/sched.h>
   9 #include <linux/module.h>
  10 #include <linux/kallsyms.h>
  11 #include <linux/fs.h>
  12 #include <linux/pm.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/slab.h>
  15 #include <linux/reboot.h>
  16 #include <linux/tick.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/unistd.h>
  19
  20 #include <asm/sysreg.h>
  21 #include <asm/ocd.h>
  22 #include <asm/syscalls.h>
  23
  24 #include <mach/pm.h>
  25
  26 void (*pm_power_off)(void);
  27 EXPORT_SYMBOL(pm_power_off);
  28
  29 /*
  30  * This file handles the architecture-dependent parts of process handling..
  31  */
  32
  33 void cpu_idle(void)
  34 {
  35         /* endless idle loop with no priority at all */
  36         while (1) {
  37                 tick_nohz_idle_enter();
  38                 rcu_idle_enter();
  39                 while (!need_resched())
  40                         cpu_idle_sleep();
  41                 rcu_idle_exit();
  42                 tick_nohz_idle_exit();
  43                 preempt_enable_no_resched();
  44                 schedule();
  45                 preempt_disable();
  46         }
  47 }
  48
  49 void machine_halt(void)
  50 {
  51         /*
  52          * Enter Stop mode. The 32 kHz oscillator will keep running so
  53          * the RTC will keep the time properly and the system will
  54          * boot quickly.
  55          */
  56         asm volatile("sleep 3\n\t"
  57                      "sub pc, -2");
  58 }
  59
  60 void machine_power_off(void)
  61 {
  62         if (pm_power_off)
  63                 pm_power_off();
  64 }
  65
  66 void machine_restart(char *cmd)
  67 {
  68         ocd_write(DC, (1 << OCD_DC_DBE_BIT));
  69         ocd_write(DC, (1 << OCD_DC_RES_BIT));
  70         while (1) ;
  71 }
  72
  73 /*
  74  * PC is actually discarded when returning from a system call -- the
  75  * return address must be stored in LR. This function will make sure
  76  * LR points to do_exit before starting the thread.
  77  *
  78  * Also, when returning from fork(), r12 is 0, so we must copy the
  79  * argument as well.
  80  *
  81  *  r0 : The argument to the main thread function
  82  *  r1 : The address of do_exit
  83  *  r2 : The address of the main thread function
  84  */
  85 asmlinkage extern void kernel_thread_helper(void);
  86 __asm__("       .type   kernel_thread_helper, @function\n"
  87         "kernel_thread_helper:\n"
  88         "       mov     r12, r0\n"
  89         "       mov     lr, r2\n"
  90         "       mov     pc, r1\n"
  91         "       .size   kernel_thread_helper, . - kernel_thread_helper");
  92
  93 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
  94 {
  95         struct pt_regs regs;
  96
  97         memset(&regs, 0, sizeof(regs));
  98
  99         regs.r0 = (unsigned long)arg;
 100         regs.r1 = (unsigned long)fn;
 101         regs.r2 = (unsigned long)do_exit;
 102         regs.lr = (unsigned long)kernel_thread_helper;
 103         regs.pc = (unsigned long)kernel_thread_helper;
 104         regs.sr = MODE_SUPERVISOR;
 105
 106         return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
 107                        0, &regs, 0, NULL, NULL);
 108 }
 109 EXPORT_SYMBOL(kernel_thread);
 110
 111 /*
 112  * Free current thread data structures etc
 113  */
 114 void exit_thread(void)
 115 {
 116         ocd_disable(current);
 117 }
 118
 119 void flush_thread(void)
 120 {
 121         /* nothing to do */
 122 }
 123
 124 void release_thread(struct task_struct *dead_task)
 125 {
 126         /* do nothing */
 127 }
 128
 129 static void dump_mem(const char *str, const char *log_lvl,
 130                      unsigned long bottom, unsigned long top)
 131 {
 132         unsigned long p;
 133         int i;
 134
 135         printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);
 136
 137         for (p = bottom & ~31; p < top; ) {
 138                 printk("%s%04lx: ", log_lvl, p & 0xffff);
 139
 140                 for (i = 0; i < 8; i++, p += 4) {
 141                         unsigned int val;
 142
 143                         if (p < bottom || p >= top)
 144                                 printk("         ");
 145                         else {
 146                                 if (__get_user(val, (unsigned int __user *)p)) {
 147                                         printk("\n");
 148                                         goto out;
 149                                 }
 150                                 printk("%08x ", val);
 151                         }
 152                 }
 153                 printk("\n");
 154         }
 155
 156 out:
 157         return;
 158 }
 159
 160 static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
 161 {
 162         return (p > (unsigned long)tinfo)
 163                 && (p < (unsigned long)tinfo + THREAD_SIZE - 3);
 164 }
 165
 166 #ifdef CONFIG_FRAME_POINTER
 167 static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
 168                                struct pt_regs *regs, const char *log_lvl)
 169 {
 170         unsigned long lr, fp;
 171         struct thread_info *tinfo;
 172
 173         if (regs)
 174                 fp = regs->r7;
 175         else if (tsk == current)
 176                 asm("mov %0, r7" : "=r"(fp));
 177         else
 178                 fp = tsk->thread.cpu_context.r7;
 179
 180         /*
 181          * Walk the stack as long as the frame pointer (a) is within
 182          * the kernel stack of the task, and (b) it doesn't move
 183          * downwards.
 184          */
 185         tinfo = task_thread_info(tsk);
 186         printk("%sCall trace:\n", log_lvl);
 187         while (valid_stack_ptr(tinfo, fp)) {
 188                 unsigned long new_fp;
 189
 190                 lr = *(unsigned long *)fp;
 191 #ifdef CONFIG_KALLSYMS
 192                 printk("%s [<%08lx>] ", log_lvl, lr);
 193 #else
 194                 printk(" [<%08lx>] ", lr);
 195 #endif
 196                 print_symbol("%s\n", lr);
 197
 198                 new_fp = *(unsigned long *)(fp + 4);
 199                 if (new_fp <= fp)
 200                         break;
 201                 fp = new_fp;
 202         }
 203         printk("\n");
 204 }
 205 #else
 206 static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
 207                                struct pt_regs *regs, const char *log_lvl)
 208 {
 209         unsigned long addr;
 210
 211         printk("%sCall trace:\n", log_lvl);
 212
 213         while (!kstack_end(sp)) {
 214                 addr = *sp++;
 215                 if (kernel_text_address(addr)) {
 216 #ifdef CONFIG_KALLSYMS
 217                         printk("%s [<%08lx>] ", log_lvl, addr);
 218 #else
 219                         printk(" [<%08lx>] ", addr);
 220 #endif
 221                         print_symbol("%s\n", addr);
 222                 }
 223         }
 224         printk("\n");
 225 }
 226 #endif
 227
 228 void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
 229                         struct pt_regs *regs, const char *log_lvl)
 230 {
 231         struct thread_info *tinfo;
 232
 233         if (sp == 0) {
 234                 if (tsk)
 235                         sp = tsk->thread.cpu_context.ksp;
 236                 else
 237                         sp = (unsigned long)&tinfo;
 238         }
 239         if (!tsk)
 240                 tsk = current;
 241
 242         tinfo = task_thread_info(tsk);
 243
 244         if (valid_stack_ptr(tinfo, sp)) {
 245                 dump_mem("Stack: ", log_lvl, sp,
 246                          THREAD_SIZE + (unsigned long)tinfo);
 247                 show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
 248         }
 249 }
 250
 251 void show_stack(struct task_struct *tsk, unsigned long *stack)
 252 {
 253         show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
 254 }
 255
 256 void dump_stack(void)
 257 {
 258         unsigned long stack;
 259
 260         show_trace_log_lvl(current, &stack, NULL, "");
 261 }
 262 EXPORT_SYMBOL(dump_stack);
 263
 264 static const char *cpu_modes[] = {
 265         "Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
 266         "Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
 267 };
 268
 269 void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
 270 {
 271         unsigned long sp = regs->sp;
 272         unsigned long lr = regs->lr;
 273         unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
 274
 275         if (!user_mode(regs)) {
 276                 sp = (unsigned long)regs + FRAME_SIZE_FULL;
 277
 278                 printk("%s", log_lvl);
 279                 print_symbol("PC is at %s\n", instruction_pointer(regs));
 280                 printk("%s", log_lvl);
 281                 print_symbol("LR is at %s\n", lr);
 282         }
 283
 284         printk("%spc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 285                "%ssp : %08lx  r12: %08lx  r11: %08lx\n",
 286                log_lvl, instruction_pointer(regs), lr, print_tainted(),
 287                log_lvl, sp, regs->r12, regs->r11);
 288         printk("%sr10: %08lx  r9 : %08lx  r8 : %08lx\n",
 289                log_lvl, regs->r10, regs->r9, regs->r8);
 290         printk("%sr7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 291                log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
 292         printk("%sr3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 293                log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
 294         printk("%sFlags: %c%c%c%c%c\n", log_lvl,
 295                regs->sr & SR_Q ? 'Q' : 'q',
 296                regs->sr & SR_V ? 'V' : 'v',
 297                regs->sr & SR_N ? 'N' : 'n',
 298                regs->sr & SR_Z ? 'Z' : 'z',
 299                regs->sr & SR_C ? 'C' : 'c');
 300         printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
 301                regs->sr & SR_H ? 'H' : 'h',
 302                regs->sr & SR_J ? 'J' : 'j',
 303                regs->sr & SR_DM ? 'M' : 'm',
 304                regs->sr & SR_D ? 'D' : 'd',
 305                regs->sr & SR_EM ? 'E' : 'e',
 306                regs->sr & SR_I3M ? '3' : '.',
 307                regs->sr & SR_I2M ? '2' : '.',
 308                regs->sr & SR_I1M ? '1' : '.',
 309                regs->sr & SR_I0M ? '0' : '.',
 310                regs->sr & SR_GM ? 'G' : 'g');
 311         printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
 312         printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
 313                log_lvl, current->comm, current->pid, current,
 314                task_thread_info(current));
 315 }
 316
 317 void show_regs(struct pt_regs *regs)
 318 {
 319         unsigned long sp = regs->sp;
 320
 321         if (!user_mode(regs))
 322                 sp = (unsigned long)regs + FRAME_SIZE_FULL;
 323
 324         show_regs_log_lvl(regs, "");
 325         show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
 326 }
 327 EXPORT_SYMBOL(show_regs);
 328
 329 /* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
 330 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 331 {
 332         /* Not valid */
 333         return 0;
 334 }
 335
 336 asmlinkage void ret_from_fork(void);
 337
 338 int copy_thread(unsigned long clone_flags, unsigned long usp,
 339                 unsigned long unused,
 340                 struct task_struct *p, struct pt_regs *regs)
 341 {
 342         struct pt_regs *childregs;
 343
 344         childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
 345         *childregs = *regs;
 346
 347         if (user_mode(regs))
 348                 childregs->sp = usp;
 349         else
 350                 childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 351
 352         childregs->r12 = 0; /* Set return value for child */
 353
 354         p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
 355         p->thread.cpu_context.ksp = (unsigned long)childregs;
 356         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 357
 358         clear_tsk_thread_flag(p, TIF_DEBUG);
 359         if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
 360                 ocd_enable(p);
 361
 362         return 0;
 363 }
 364
 365 /* r12-r8 are dummy parameters to force the compiler to use the stack */
 366 asmlinkage int sys_fork(struct pt_regs *regs)
 367 {
 368         return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
 369 }
 370
 371 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 372                 void __user *parent_tidptr, void __user *child_tidptr,
 373                 struct pt_regs *regs)
 374 {
 375         if (!newsp)
 376                 newsp = regs->sp;
 377         return do_fork(clone_flags, newsp, regs, 0, parent_tidptr,
 378                         child_tidptr);
 379 }
 380
 381 asmlinkage int sys_vfork(struct pt_regs *regs)
 382 {
 383         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
 384                        0, NULL, NULL);
 385 }
 386
 387 asmlinkage int sys_execve(const char __user *ufilename,
 388                           const char __user *const __user *uargv,
 389                           const char __user *const __user *uenvp,
 390                           struct pt_regs *regs)
 391 {
 392         int error;
 393         char *filename;
 394
 395         filename = getname(ufilename);
 396         error = PTR_ERR(filename);
 397         if (IS_ERR(filename))
 398                 goto out;
 399
 400         error = do_execve(filename, uargv, uenvp, regs);
 401         putname(filename);
 402
 403 out:
 404         return error;
 405 }
 406
 407
 408 /*
 409  * This function is supposed to answer the question "who called
 410  * schedule()?"
 411  */
 412 unsigned long get_wchan(struct task_struct *p)
 413 {
 414         unsigned long pc;
 415         unsigned long stack_page;
 416
 417         if (!p || p == current || p->state == TASK_RUNNING)
 418                 return 0;
 419
 420         stack_page = (unsigned long)task_stack_page(p);
 421         BUG_ON(!stack_page);
 422
 423         /*
 424          * The stored value of PC is either the address right after
 425          * the call to __switch_to() or ret_from_fork.
 426          */
 427         pc = thread_saved_pc(p);
 428         if (in_sched_functions(pc)) {
 429 #ifdef CONFIG_FRAME_POINTER
 430                 unsigned long fp = p->thread.cpu_context.r7;
 431                 BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
 432                 pc = *(unsigned long *)fp;
 433 #else
 434                 /*
 435                  * We depend on the frame size of schedule here, which
 436                  * is actually quite ugly. It might be possible to
 437                  * determine the frame size automatically at build
 438                  * time by doing this:
 439                  *   - compile sched.c
 440                  *   - disassemble the resulting sched.o
 441                  *   - look for 'sub sp,??' shortly after '<schedule>:'
 442                  */
 443                 unsigned long sp = p->thread.cpu_context.ksp + 16;
 444                 BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
 445                 pc = *(unsigned long *)sp;
 446 #endif
 447         }
 448
 449         return pc;
 450 }