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