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