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