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