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