linux/arch/avr32/kernel/process.c
<<
>>
Prefs
   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#include <mach/pm.h>
  22
  23void (*pm_power_off)(void) = NULL;
  24EXPORT_SYMBOL(pm_power_off);
  25
  26/*
  27 * This file handles the architecture-dependent parts of process handling..
  28 */
  29
  30void cpu_idle(void)
  31{
  32        /* endless idle loop with no priority at all */
  33        while (1) {
  34                tick_nohz_stop_sched_tick(1);
  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
  44void 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
  55void machine_power_off(void)
  56{
  57        if (pm_power_off)
  58                pm_power_off();
  59}
  60
  61void machine_restart(char *cmd)
  62{
  63        ocd_write(DC, (1 << OCD_DC_DBE_BIT));
  64        ocd_write(DC, (1 << OCD_DC_RES_BIT));
  65        while (1) ;
  66}
  67
  68/*
  69 * PC is actually discarded when returning from a system call -- the
  70 * return address must be stored in LR. This function will make sure
  71 * LR points to do_exit before starting the thread.
  72 *
  73 * Also, when returning from fork(), r12 is 0, so we must copy the
  74 * argument as well.
  75 *
  76 *  r0 : The argument to the main thread function
  77 *  r1 : The address of do_exit
  78 *  r2 : The address of the main thread function
  79 */
  80asmlinkage extern void kernel_thread_helper(void);
  81__asm__("       .type   kernel_thread_helper, @function\n"
  82        "kernel_thread_helper:\n"
  83        "       mov     r12, r0\n"
  84        "       mov     lr, r2\n"
  85        "       mov     pc, r1\n"
  86        "       .size   kernel_thread_helper, . - kernel_thread_helper");
  87
  88int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
  89{
  90        struct pt_regs regs;
  91
  92        memset(&regs, 0, sizeof(regs));
  93
  94        regs.r0 = (unsigned long)arg;
  95        regs.r1 = (unsigned long)fn;
  96        regs.r2 = (unsigned long)do_exit;
  97        regs.lr = (unsigned long)kernel_thread_helper;
  98        regs.pc = (unsigned long)kernel_thread_helper;
  99        regs.sr = MODE_SUPERVISOR;
 100
 101        return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
 102                       0, &regs, 0, NULL, NULL);
 103}
 104EXPORT_SYMBOL(kernel_thread);
 105
 106/*
 107 * Free current thread data structures etc
 108 */
 109void exit_thread(void)
 110{
 111        ocd_disable(current);
 112}
 113
 114void flush_thread(void)
 115{
 116        /* nothing to do */
 117}
 118
 119void release_thread(struct task_struct *dead_task)
 120{
 121        /* do nothing */
 122}
 123
 124static void dump_mem(const char *str, const char *log_lvl,
 125                     unsigned long bottom, unsigned long top)
 126{
 127        unsigned long p;
 128        int i;
 129
 130        printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);
 131
 132        for (p = bottom & ~31; p < top; ) {
 133                printk("%s%04lx: ", log_lvl, p & 0xffff);
 134
 135                for (i = 0; i < 8; i++, p += 4) {
 136                        unsigned int val;
 137
 138                        if (p < bottom || p >= top)
 139                                printk("         ");
 140                        else {
 141                                if (__get_user(val, (unsigned int __user *)p)) {
 142                                        printk("\n");
 143                                        goto out;
 144                                }
 145                                printk("%08x ", val);
 146                        }
 147                }
 148                printk("\n");
 149        }
 150
 151out:
 152        return;
 153}
 154
 155static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
 156{
 157        return (p > (unsigned long)tinfo)
 158                && (p < (unsigned long)tinfo + THREAD_SIZE - 3);
 159}
 160
 161#ifdef CONFIG_FRAME_POINTER
 162static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
 163                               struct pt_regs *regs, const char *log_lvl)
 164{
 165        unsigned long lr, fp;
 166        struct thread_info *tinfo;
 167
 168        if (regs)
 169                fp = regs->r7;
 170        else if (tsk == current)
 171                asm("mov %0, r7" : "=r"(fp));
 172        else
 173                fp = tsk->thread.cpu_context.r7;
 174
 175        /*
 176         * Walk the stack as long as the frame pointer (a) is within
 177         * the kernel stack of the task, and (b) it doesn't move
 178         * downwards.
 179         */
 180        tinfo = task_thread_info(tsk);
 181        printk("%sCall trace:\n", log_lvl);
 182        while (valid_stack_ptr(tinfo, fp)) {
 183                unsigned long new_fp;
 184
 185                lr = *(unsigned long *)fp;
 186#ifdef CONFIG_KALLSYMS
 187                printk("%s [<%08lx>] ", log_lvl, lr);
 188#else
 189                printk(" [<%08lx>] ", lr);
 190#endif
 191                print_symbol("%s\n", lr);
 192
 193                new_fp = *(unsigned long *)(fp + 4);
 194                if (new_fp <= fp)
 195                        break;
 196                fp = new_fp;
 197        }
 198        printk("\n");
 199}
 200#else
 201static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
 202                               struct pt_regs *regs, const char *log_lvl)
 203{
 204        unsigned long addr;
 205
 206        printk("%sCall trace:\n", log_lvl);
 207
 208        while (!kstack_end(sp)) {
 209                addr = *sp++;
 210                if (kernel_text_address(addr)) {
 211#ifdef CONFIG_KALLSYMS
 212                        printk("%s [<%08lx>] ", log_lvl, addr);
 213#else
 214                        printk(" [<%08lx>] ", addr);
 215#endif
 216                        print_symbol("%s\n", addr);
 217                }
 218        }
 219        printk("\n");
 220}
 221#endif
 222
 223void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
 224                        struct pt_regs *regs, const char *log_lvl)
 225{
 226        struct thread_info *tinfo;
 227
 228        if (sp == 0) {
 229                if (tsk)
 230                        sp = tsk->thread.cpu_context.ksp;
 231                else
 232                        sp = (unsigned long)&tinfo;
 233        }
 234        if (!tsk)
 235                tsk = current;
 236
 237        tinfo = task_thread_info(tsk);
 238
 239        if (valid_stack_ptr(tinfo, sp)) {
 240                dump_mem("Stack: ", log_lvl, sp,
 241                         THREAD_SIZE + (unsigned long)tinfo);
 242                show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
 243        }
 244}
 245
 246void show_stack(struct task_struct *tsk, unsigned long *stack)
 247{
 248        show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
 249}
 250
 251void dump_stack(void)
 252{
 253        unsigned long stack;
 254
 255        show_trace_log_lvl(current, &stack, NULL, "");
 256}
 257EXPORT_SYMBOL(dump_stack);
 258
 259static const char *cpu_modes[] = {
 260        "Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
 261        "Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
 262};
 263
 264void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
 265{
 266        unsigned long sp = regs->sp;
 267        unsigned long lr = regs->lr;
 268        unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
 269
 270        if (!user_mode(regs)) {
 271                sp = (unsigned long)regs + FRAME_SIZE_FULL;
 272
 273                printk("%s", log_lvl);
 274                print_symbol("PC is at %s\n", instruction_pointer(regs));
 275                printk("%s", log_lvl);
 276                print_symbol("LR is at %s\n", lr);
 277        }
 278
 279        printk("%spc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 280               "%ssp : %08lx  r12: %08lx  r11: %08lx\n",
 281               log_lvl, instruction_pointer(regs), lr, print_tainted(),
 282               log_lvl, sp, regs->r12, regs->r11);
 283        printk("%sr10: %08lx  r9 : %08lx  r8 : %08lx\n",
 284               log_lvl, regs->r10, regs->r9, regs->r8);
 285        printk("%sr7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 286               log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
 287        printk("%sr3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 288               log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
 289        printk("%sFlags: %c%c%c%c%c\n", log_lvl,
 290               regs->sr & SR_Q ? 'Q' : 'q',
 291               regs->sr & SR_V ? 'V' : 'v',
 292               regs->sr & SR_N ? 'N' : 'n',
 293               regs->sr & SR_Z ? 'Z' : 'z',
 294               regs->sr & SR_C ? 'C' : 'c');
 295        printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
 296               regs->sr & SR_H ? 'H' : 'h',
 297               regs->sr & SR_J ? 'J' : 'j',
 298               regs->sr & SR_DM ? 'M' : 'm',
 299               regs->sr & SR_D ? 'D' : 'd',
 300               regs->sr & SR_EM ? 'E' : 'e',
 301               regs->sr & SR_I3M ? '3' : '.',
 302               regs->sr & SR_I2M ? '2' : '.',
 303               regs->sr & SR_I1M ? '1' : '.',
 304               regs->sr & SR_I0M ? '0' : '.',
 305               regs->sr & SR_GM ? 'G' : 'g');
 306        printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
 307        printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
 308               log_lvl, current->comm, current->pid, current,
 309               task_thread_info(current));
 310}
 311
 312void show_regs(struct pt_regs *regs)
 313{
 314        unsigned long sp = regs->sp;
 315
 316        if (!user_mode(regs))
 317                sp = (unsigned long)regs + FRAME_SIZE_FULL;
 318
 319        show_regs_log_lvl(regs, "");
 320        show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
 321}
 322EXPORT_SYMBOL(show_regs);
 323
 324/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
 325int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 326{
 327        /* Not valid */
 328        return 0;
 329}
 330
 331asmlinkage void ret_from_fork(void);
 332
 333int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 334                unsigned long unused,
 335                struct task_struct *p, struct pt_regs *regs)
 336{
 337        struct pt_regs *childregs;
 338
 339        childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
 340        *childregs = *regs;
 341
 342        if (user_mode(regs))
 343                childregs->sp = usp;
 344        else
 345                childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 346
 347        childregs->r12 = 0; /* Set return value for child */
 348
 349        p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
 350        p->thread.cpu_context.ksp = (unsigned long)childregs;
 351        p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 352
 353        clear_tsk_thread_flag(p, TIF_DEBUG);
 354        if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
 355                ocd_enable(p);
 356
 357        return 0;
 358}
 359
 360/* r12-r8 are dummy parameters to force the compiler to use the stack */
 361asmlinkage int sys_fork(struct pt_regs *regs)
 362{
 363        return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
 364}
 365
 366asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 367                         unsigned long parent_tidptr,
 368                         unsigned long child_tidptr, struct pt_regs *regs)
 369{
 370        if (!newsp)
 371                newsp = regs->sp;
 372        return do_fork(clone_flags, newsp, regs, 0,
 373                       (int __user *)parent_tidptr,
 374                       (int __user *)child_tidptr);
 375}
 376
 377asmlinkage int sys_vfork(struct pt_regs *regs)
 378{
 379        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
 380                       0, NULL, NULL);
 381}
 382
 383asmlinkage int sys_execve(char __user *ufilename, char __user *__user *uargv,
 384                          char __user *__user *uenvp, struct pt_regs *regs)
 385{
 386        int error;
 387        char *filename;
 388
 389        filename = getname(ufilename);
 390        error = PTR_ERR(filename);
 391        if (IS_ERR(filename))
 392                goto out;
 393
 394        error = do_execve(filename, uargv, uenvp, regs);
 395        if (error == 0)
 396                current->ptrace &= ~PT_DTRACE;
 397        putname(filename);
 398
 399out:
 400        return error;
 401}
 402
 403
 404/*
 405 * This function is supposed to answer the question "who called
 406 * schedule()?"
 407 */
 408unsigned long get_wchan(struct task_struct *p)
 409{
 410        unsigned long pc;
 411        unsigned long stack_page;
 412
 413        if (!p || p == current || p->state == TASK_RUNNING)
 414                return 0;
 415
 416        stack_page = (unsigned long)task_stack_page(p);
 417        BUG_ON(!stack_page);
 418
 419        /*
 420         * The stored value of PC is either the address right after
 421         * the call to __switch_to() or ret_from_fork.
 422         */
 423        pc = thread_saved_pc(p);
 424        if (in_sched_functions(pc)) {
 425#ifdef CONFIG_FRAME_POINTER
 426                unsigned long fp = p->thread.cpu_context.r7;
 427                BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
 428                pc = *(unsigned long *)fp;
 429#else
 430                /*
 431                 * We depend on the frame size of schedule here, which
 432                 * is actually quite ugly. It might be possible to
 433                 * determine the frame size automatically at build
 434                 * time by doing this:
 435                 *   - compile sched.c
 436                 *   - disassemble the resulting sched.o
 437                 *   - look for 'sub sp,??' shortly after '<schedule>:'
 438                 */
 439                unsigned long sp = p->thread.cpu_context.ksp + 16;
 440                BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
 441                pc = *(unsigned long *)sp;
 442#endif
 443        }
 444
 445        return pc;
 446}
 447