arch/arm/kernel/process.c

   1 /*
   2  *  linux/arch/arm/kernel/process.c
   3  *
   4  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
   5  *  Original Copyright (C) 1995  Linus Torvalds
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <stdarg.h>
  12
  13 #include <linux/module.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/stddef.h>
  18 #include <linux/unistd.h>
  19 #include <linux/user.h>
  20 #include <linux/delay.h>
  21 #include <linux/reboot.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/init.h>
  25 #include <linux/cpu.h>
  26 #include <linux/elfcore.h>
  27 #include <linux/pm.h>
  28 #include <linux/tick.h>
  29 #include <linux/utsname.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/random.h>
  32
  33 #include <asm/cacheflush.h>
  34 #include <asm/leds.h>
  35 #include <asm/processor.h>
  36 #include <asm/system.h>
  37 #include <asm/thread_notify.h>
  38 #include <asm/stacktrace.h>
  39 #include <asm/mach/time.h>
  40
  41 #ifdef CONFIG_CC_STACKPROTECTOR
  42 #include <linux/stackprotector.h>
  43 unsigned long __stack_chk_guard __read_mostly;
  44 EXPORT_SYMBOL(__stack_chk_guard);
  45 #endif
  46
  47 static const char *processor_modes[] = {
  48   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  49   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  50   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  51   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  52 };
  53
  54 static const char *isa_modes[] = {
  55   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  56 };
  57
  58 extern void setup_mm_for_reboot(char mode);
  59
  60 static volatile int hlt_counter;
  61
  62 #include <mach/system.h>
  63
  64 void disable_hlt(void)
  65 {
  66         hlt_counter++;
  67 }
  68
  69 EXPORT_SYMBOL(disable_hlt);
  70
  71 void enable_hlt(void)
  72 {
  73         hlt_counter--;
  74 }
  75
  76 EXPORT_SYMBOL(enable_hlt);
  77
  78 static int __init nohlt_setup(char *__unused)
  79 {
  80         hlt_counter = 1;
  81         return 1;
  82 }
  83
  84 static int __init hlt_setup(char *__unused)
  85 {
  86         hlt_counter = 0;
  87         return 1;
  88 }
  89
  90 __setup("nohlt", nohlt_setup);
  91 __setup("hlt", hlt_setup);
  92
  93 void arm_machine_restart(char mode, const char *cmd)
  94 {
  95         /* Disable interrupts first */
  96         local_irq_disable();
  97         local_fiq_disable();
  98
  99         /*
 100          * Tell the mm system that we are going to reboot -
 101          * we may need it to insert some 1:1 mappings so that
 102          * soft boot works.
 103          */
 104         setup_mm_for_reboot(mode);
 105
 106         /* Clean and invalidate caches */
 107         flush_cache_all();
 108
 109         /* Turn off caching */
 110         cpu_proc_fin();
 111
 112         /* Push out any further dirty data, and ensure cache is empty */
 113         flush_cache_all();
 114
 115         /*
 116          * Now call the architecture specific reboot code.
 117          */
 118         arch_reset(mode, cmd);
 119
 120         /*
 121          * Whoops - the architecture was unable to reboot.
 122          * Tell the user!
 123          */
 124         mdelay(1000);
 125         printk("Reboot failed -- System halted\n");
 126         while (1);
 127 }
 128
 129 /*
 130  * Function pointers to optional machine specific functions
 131  */
 132 void (*pm_power_off)(void);
 133 EXPORT_SYMBOL(pm_power_off);
 134
 135 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 136 EXPORT_SYMBOL_GPL(arm_pm_restart);
 137
 138
 139 /*
 140  * This is our default idle handler.  We need to disable
 141  * interrupts here to ensure we don't miss a wakeup call.
 142  */
 143 void default_idle(void)
 144 {
 145         if (!need_resched())
 146                 arch_idle();
 147         local_irq_enable();
 148 }
 149 EXPORT_SYMBOL(default_idle);
 150
 151 void (*pm_idle)(void) = default_idle;
 152 EXPORT_SYMBOL(pm_idle);
 153
 154 /*
 155  * The idle thread, has rather strange semantics for calling pm_idle,
 156  * but this is what x86 does and we need to do the same, so that
 157  * things like cpuidle get called in the same way.  The only difference
 158  * is that we always respect 'hlt_counter' to prevent low power idle.
 159  */
 160 void cpu_idle(void)
 161 {
 162         local_fiq_enable();
 163
 164         /* endless idle loop with no priority at all */
 165         while (1) {
 166                 tick_nohz_stop_sched_tick(1);
 167                 leds_event(led_idle_start);
 168                 while (!need_resched()) {
 169 #ifdef CONFIG_HOTPLUG_CPU
 170                         if (cpu_is_offline(smp_processor_id()))
 171                                 cpu_die();
 172 #endif
 173
 174                         local_irq_disable();
 175                         if (hlt_counter) {
 176                                 local_irq_enable();
 177                                 cpu_relax();
 178                         } else {
 179                                 stop_critical_timings();
 180                                 pm_idle();
 181                                 start_critical_timings();
 182                                 /*
 183                                  * This will eventually be removed - pm_idle
 184                                  * functions should always return with IRQs
 185                                  * enabled.
 186                                  */
 187                                 WARN_ON(irqs_disabled());
 188                                 local_irq_enable();
 189                         }
 190                 }
 191                 leds_event(led_idle_end);
 192                 tick_nohz_restart_sched_tick();
 193                 preempt_enable_no_resched();
 194                 schedule();
 195                 preempt_disable();
 196         }
 197 }
 198
 199 #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
 200 static void do_nothing(void *unused)
 201 {
 202 }
 203
 204 void cpu_idle_wait(void)
 205 {
 206         smp_mb();
 207         smp_call_function(do_nothing, NULL, 1);
 208 }
 209 #endif
 210
 211
 212 static char reboot_mode = 'h';
 213
 214 int __init reboot_setup(char *str)
 215 {
 216         reboot_mode = str[0];
 217         return 1;
 218 }
 219
 220 __setup("reboot=", reboot_setup);
 221
 222 void machine_shutdown(void)
 223 {
 224 #ifdef CONFIG_SMP
 225         smp_send_stop();
 226 #endif
 227 }
 228
 229 void machine_halt(void)
 230 {
 231         machine_shutdown();
 232         while (1);
 233 }
 234
 235 void machine_power_off(void)
 236 {
 237         machine_shutdown();
 238         if (pm_power_off)
 239                 pm_power_off();
 240 }
 241
 242 void machine_restart(char *cmd)
 243 {
 244         machine_shutdown();
 245         arm_pm_restart(reboot_mode, cmd);
 246 }
 247
 248 /*
 249  * dump a block of kernel memory from around the given address
 250  */
 251 static void show_data(unsigned long addr, int nbytes, const char *name)
 252 {
 253         int     i, j;
 254         int     nlines;
 255         u32     *p;
 256
 257         /*
 258          * don't attempt to dump non-kernel addresses or
 259          * values that are probably just small negative numbers
 260          */
 261         if (addr < PAGE_OFFSET || addr > -256UL)
 262                 return;
 263
 264         printk("\n%s: %#lx:\n", name, addr);
 265
 266         /*
 267          * round address down to a 32 bit boundary
 268          * and always dump a multiple of 32 bytes
 269          */
 270         p = (u32 *)(addr & ~(sizeof(u32) - 1));
 271         nbytes += (addr & (sizeof(u32) - 1));
 272         nlines = (nbytes + 31) / 32;
 273
 274
 275         for (i = 0; i < nlines; i++) {
 276                 /*
 277                  * just display low 16 bits of address to keep
 278                  * each line of the dump < 80 characters
 279                  */
 280                 printk("%04lx ", (unsigned long)p & 0xffff);
 281                 for (j = 0; j < 8; j++) {
 282                         u32     data;
 283                         if (probe_kernel_address(p, data)) {
 284                                 printk(" ********");
 285                         } else {
 286                                 printk(" %08x", data);
 287                         }
 288                         ++p;
 289                 }
 290                 printk("\n");
 291         }
 292 }
 293
 294 static void show_extra_register_data(struct pt_regs *regs, int nbytes)
 295 {
 296         mm_segment_t fs;
 297
 298         fs = get_fs();
 299         set_fs(KERNEL_DS);
 300         show_data(regs->ARM_pc - nbytes, nbytes * 2, "PC");
 301         show_data(regs->ARM_lr - nbytes, nbytes * 2, "LR");
 302         show_data(regs->ARM_sp - nbytes, nbytes * 2, "SP");
 303         show_data(regs->ARM_ip - nbytes, nbytes * 2, "IP");
 304         show_data(regs->ARM_fp - nbytes, nbytes * 2, "FP");
 305         show_data(regs->ARM_r0 - nbytes, nbytes * 2, "R0");
 306         show_data(regs->ARM_r1 - nbytes, nbytes * 2, "R1");
 307         show_data(regs->ARM_r2 - nbytes, nbytes * 2, "R2");
 308         show_data(regs->ARM_r3 - nbytes, nbytes * 2, "R3");
 309         show_data(regs->ARM_r4 - nbytes, nbytes * 2, "R4");
 310         show_data(regs->ARM_r5 - nbytes, nbytes * 2, "R5");
 311         show_data(regs->ARM_r6 - nbytes, nbytes * 2, "R6");
 312         show_data(regs->ARM_r7 - nbytes, nbytes * 2, "R7");
 313         show_data(regs->ARM_r8 - nbytes, nbytes * 2, "R8");
 314         show_data(regs->ARM_r9 - nbytes, nbytes * 2, "R9");
 315         show_data(regs->ARM_r10 - nbytes, nbytes * 2, "R10");
 316         set_fs(fs);
 317 }
 318
 319 void __show_regs(struct pt_regs *regs)
 320 {
 321         unsigned long flags;
 322         char buf[64];
 323
 324         printk("CPU: %d    %s  (%s %.*s)\n",
 325                 raw_smp_processor_id(), print_tainted(),
 326                 init_utsname()->release,
 327                 (int)strcspn(init_utsname()->version, " "),
 328                 init_utsname()->version);
 329         print_symbol("PC is at %s\n", instruction_pointer(regs));
 330         print_symbol("LR is at %s\n", regs->ARM_lr);
 331         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 332                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 333                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 334                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 335         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 336                 regs->ARM_r10, regs->ARM_r9,
 337                 regs->ARM_r8);
 338         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 339                 regs->ARM_r7, regs->ARM_r6,
 340                 regs->ARM_r5, regs->ARM_r4);
 341         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 342                 regs->ARM_r3, regs->ARM_r2,
 343                 regs->ARM_r1, regs->ARM_r0);
 344
 345         flags = regs->ARM_cpsr;
 346         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 347         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 348         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 349         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 350         buf[4] = '\0';
 351
 352         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 353                 buf, interrupts_enabled(regs) ? "n" : "ff",
 354                 fast_interrupts_enabled(regs) ? "n" : "ff",
 355                 processor_modes[processor_mode(regs)],
 356                 isa_modes[isa_mode(regs)],
 357                 get_fs() == get_ds() ? "kernel" : "user");
 358 #ifdef CONFIG_CPU_CP15
 359         {
 360                 unsigned int ctrl;
 361
 362                 buf[0] = '\0';
 363 #ifdef CONFIG_CPU_CP15_MMU
 364                 {
 365                         unsigned int transbase, dac;
 366                         asm("mrc p15, 0, %0, c2, c0\n\t"
 367                             "mrc p15, 0, %1, c3, c0\n"
 368                             : "=r" (transbase), "=r" (dac));
 369                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 370                                 transbase, dac);
 371                 }
 372 #endif
 373                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 374
 375                 printk("Control: %08x%s\n", ctrl, buf);
 376         }
 377 #endif
 378
 379         show_extra_register_data(regs, 128);
 380 }
 381
 382 void show_regs(struct pt_regs * regs)
 383 {
 384         printk("\n");
 385         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 386         __show_regs(regs);
 387         __backtrace();
 388 }
 389
 390 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 391
 392 EXPORT_SYMBOL_GPL(thread_notify_head);
 393
 394 /*
 395  * Free current thread data structures etc..
 396  */
 397 void exit_thread(void)
 398 {
 399         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 400 }
 401
 402 void flush_thread(void)
 403 {
 404         struct thread_info *thread = current_thread_info();
 405         struct task_struct *tsk = current;
 406
 407         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 408         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 409         memset(&thread->fpstate, 0, sizeof(union fp_state));
 410
 411         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 412 }
 413
 414 void release_thread(struct task_struct *dead_task)
 415 {
 416 }
 417
 418 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 419
 420 int
 421 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 422             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 423 {
 424         struct thread_info *thread = task_thread_info(p);
 425         struct pt_regs *childregs = task_pt_regs(p);
 426
 427         *childregs = *regs;
 428         childregs->ARM_r0 = 0;
 429         childregs->ARM_sp = stack_start;
 430
 431         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 432         thread->cpu_context.sp = (unsigned long)childregs;
 433         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 434
 435         if (clone_flags & CLONE_SETTLS)
 436                 thread->tp_value = regs->ARM_r3;
 437
 438         return 0;
 439 }
 440
 441 /*
 442  * Fill in the task's elfregs structure for a core dump.
 443  */
 444 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 445 {
 446         elf_core_copy_regs(elfregs, task_pt_regs(t));
 447         return 1;
 448 }
 449
 450 /*
 451  * fill in the fpe structure for a core dump...
 452  */
 453 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 454 {
 455         struct thread_info *thread = current_thread_info();
 456         int used_math = thread->used_cp[1] | thread->used_cp[2];
 457
 458         if (used_math)
 459                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 460
 461         return used_math != 0;
 462 }
 463 EXPORT_SYMBOL(dump_fpu);
 464
 465 /*
 466  * Shuffle the argument into the correct register before calling the
 467  * thread function.  r4 is the thread argument, r5 is the pointer to
 468  * the thread function, and r6 points to the exit function.
 469  */
 470 extern void kernel_thread_helper(void);
 471 asm(    ".pushsection .text\n"
 472 "       .align\n"
 473 "       .type   kernel_thread_helper, #function\n"
 474 "kernel_thread_helper:\n"
 475 #ifdef CONFIG_TRACE_IRQFLAGS
 476 "       bl      trace_hardirqs_on\n"
 477 #endif
 478 "       msr     cpsr_c, r7\n"
 479 "       mov     r0, r4\n"
 480 "       mov     lr, r6\n"
 481 "       mov     pc, r5\n"
 482 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 483 "       .popsection");
 484
 485 #ifdef CONFIG_ARM_UNWIND
 486 extern void kernel_thread_exit(long code);
 487 asm(    ".pushsection .text\n"
 488 "       .align\n"
 489 "       .type   kernel_thread_exit, #function\n"
 490 "kernel_thread_exit:\n"
 491 "       .fnstart\n"
 492 "       .cantunwind\n"
 493 "       bl      do_exit\n"
 494 "       nop\n"
 495 "       .fnend\n"
 496 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 497 "       .popsection");
 498 #else
 499 #define kernel_thread_exit      do_exit
 500 #endif
 501
 502 /*
 503  * Create a kernel thread.
 504  */
 505 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 506 {
 507         struct pt_regs regs;
 508
 509         memset(&regs, 0, sizeof(regs));
 510
 511         regs.ARM_r4 = (unsigned long)arg;
 512         regs.ARM_r5 = (unsigned long)fn;
 513         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 514         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 515         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 516         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 517
 518         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 519 }
 520 EXPORT_SYMBOL(kernel_thread);
 521
 522 unsigned long get_wchan(struct task_struct *p)
 523 {
 524         struct stackframe frame;
 525         int count = 0;
 526         if (!p || p == current || p->state == TASK_RUNNING)
 527                 return 0;
 528
 529         frame.fp = thread_saved_fp(p);
 530         frame.sp = thread_saved_sp(p);
 531         frame.lr = 0;                   /* recovered from the stack */
 532         frame.pc = thread_saved_pc(p);
 533         do {
 534                 int ret = unwind_frame(&frame);
 535                 if (ret < 0)
 536                         return 0;
 537                 if (!in_sched_functions(frame.pc))
 538                         return frame.pc;
 539         } while (count ++ < 16);
 540         return 0;
 541 }
 542
 543 unsigned long arch_randomize_brk(struct mm_struct *mm)
 544 {
 545         unsigned long range_end = mm->brk + 0x02000000;
 546         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 547 }