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