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 #include <linux/hw_breakpoint.h>
  33 #include <linux/cpuidle.h>
  34
  35 #include <asm/cacheflush.h>
  36 #include <asm/leds.h>
  37 #include <asm/processor.h>
  38 #include <asm/system.h>
  39 #include <asm/thread_notify.h>
  40 #include <asm/stacktrace.h>
  41 #include <asm/mach/time.h>
  42
  43 #ifdef CONFIG_CC_STACKPROTECTOR
  44 #include <linux/stackprotector.h>
  45 unsigned long __stack_chk_guard __read_mostly;
  46 EXPORT_SYMBOL(__stack_chk_guard);
  47 #endif
  48
  49 static const char *processor_modes[] = {
  50   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  51   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  52   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  53   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  54 };
  55
  56 static const char *isa_modes[] = {
  57   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  58 };
  59
  60 extern void setup_mm_for_reboot(char mode);
  61
  62 static volatile int hlt_counter;
  63
  64 #include <mach/system.h>
  65
  66 void disable_hlt(void)
  67 {
  68         hlt_counter++;
  69 }
  70
  71 EXPORT_SYMBOL(disable_hlt);
  72
  73 void enable_hlt(void)
  74 {
  75         hlt_counter--;
  76 }
  77
  78 EXPORT_SYMBOL(enable_hlt);
  79
  80 static int __init nohlt_setup(char *__unused)
  81 {
  82         hlt_counter = 1;
  83         return 1;
  84 }
  85
  86 static int __init hlt_setup(char *__unused)
  87 {
  88         hlt_counter = 0;
  89         return 1;
  90 }
  91
  92 __setup("nohlt", nohlt_setup);
  93 __setup("hlt", hlt_setup);
  94
  95 void arm_machine_restart(char mode, const char *cmd)
  96 {
  97         /* Disable interrupts first */
  98         local_irq_disable();
  99         local_fiq_disable();
 100
 101         /*
 102          * Tell the mm system that we are going to reboot -
 103          * we may need it to insert some 1:1 mappings so that
 104          * soft boot works.
 105          */
 106         setup_mm_for_reboot(mode);
 107
 108         /* Clean and invalidate caches */
 109         flush_cache_all();
 110
 111         /* Turn off caching */
 112         cpu_proc_fin();
 113
 114         /* Push out any further dirty data, and ensure cache is empty */
 115         flush_cache_all();
 116
 117         /*
 118          * Now call the architecture specific reboot code.
 119          */
 120         arch_reset(mode, cmd);
 121
 122         /*
 123          * Whoops - the architecture was unable to reboot.
 124          * Tell the user!
 125          */
 126         mdelay(1000);
 127         printk("Reboot failed -- System halted\n");
 128         while (1);
 129 }
 130
 131 /*
 132  * Function pointers to optional machine specific functions
 133  */
 134 void (*pm_power_off)(void);
 135 EXPORT_SYMBOL(pm_power_off);
 136
 137 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 138 EXPORT_SYMBOL_GPL(arm_pm_restart);
 139
 140 static void do_nothing(void *unused)
 141 {
 142 }
 143
 144 /*
 145  * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
 146  * pm_idle and update to new pm_idle value. Required while changing pm_idle
 147  * handler on SMP systems.
 148  *
 149  * Caller must have changed pm_idle to the new value before the call. Old
 150  * pm_idle value will not be used by any CPU after the return of this function.
 151  */
 152 void cpu_idle_wait(void)
 153 {
 154         smp_mb();
 155         /* kick all the CPUs so that they exit out of pm_idle */
 156         smp_call_function(do_nothing, NULL, 1);
 157 }
 158 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 159
 160 /*
 161  * This is our default idle handler.  We need to disable
 162  * interrupts here to ensure we don't miss a wakeup call.
 163  */
 164 static void default_idle(void)
 165 {
 166         if (!need_resched())
 167                 arch_idle();
 168         local_irq_enable();
 169 }
 170
 171 void (*pm_idle)(void) = default_idle;
 172 EXPORT_SYMBOL(pm_idle);
 173
 174 /*
 175  * The idle thread, has rather strange semantics for calling pm_idle,
 176  * but this is what x86 does and we need to do the same, so that
 177  * things like cpuidle get called in the same way.  The only difference
 178  * is that we always respect 'hlt_counter' to prevent low power idle.
 179  */
 180 void cpu_idle(void)
 181 {
 182         local_fiq_enable();
 183
 184         /* endless idle loop with no priority at all */
 185         while (1) {
 186                 tick_nohz_stop_sched_tick(1);
 187                 leds_event(led_idle_start);
 188                 while (!need_resched()) {
 189 #ifdef CONFIG_HOTPLUG_CPU
 190                         if (cpu_is_offline(smp_processor_id()))
 191                                 cpu_die();
 192 #endif
 193
 194                         local_irq_disable();
 195                         if (hlt_counter) {
 196                                 local_irq_enable();
 197                                 cpu_relax();
 198                         } else {
 199                                 stop_critical_timings();
 200                                 if (cpuidle_idle_call())
 201                                         pm_idle();
 202                                 start_critical_timings();
 203                                 /*
 204                                  * This will eventually be removed - pm_idle
 205                                  * functions should always return with IRQs
 206                                  * enabled.
 207                                  */
 208                                 WARN_ON(irqs_disabled());
 209                                 local_irq_enable();
 210                         }
 211                 }
 212                 leds_event(led_idle_end);
 213                 tick_nohz_restart_sched_tick();
 214                 preempt_enable_no_resched();
 215                 schedule();
 216                 preempt_disable();
 217         }
 218 }
 219
 220 static char reboot_mode = 'h';
 221
 222 int __init reboot_setup(char *str)
 223 {
 224         reboot_mode = str[0];
 225         return 1;
 226 }
 227
 228 __setup("reboot=", reboot_setup);
 229
 230 void machine_shutdown(void)
 231 {
 232 #ifdef CONFIG_SMP
 233         smp_send_stop();
 234 #endif
 235 }
 236
 237 void machine_halt(void)
 238 {
 239         machine_shutdown();
 240         while (1);
 241 }
 242
 243 void machine_power_off(void)
 244 {
 245         machine_shutdown();
 246         if (pm_power_off)
 247                 pm_power_off();
 248 }
 249
 250 void machine_restart(char *cmd)
 251 {
 252         machine_shutdown();
 253         arm_pm_restart(reboot_mode, cmd);
 254 }
 255
 256 void __show_regs(struct pt_regs *regs)
 257 {
 258         unsigned long flags;
 259         char buf[64];
 260
 261         printk("CPU: %d    %s  (%s %.*s)\n",
 262                 raw_smp_processor_id(), print_tainted(),
 263                 init_utsname()->release,
 264                 (int)strcspn(init_utsname()->version, " "),
 265                 init_utsname()->version);
 266         print_symbol("PC is at %s\n", instruction_pointer(regs));
 267         print_symbol("LR is at %s\n", regs->ARM_lr);
 268         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 269                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 270                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 271                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 272         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 273                 regs->ARM_r10, regs->ARM_r9,
 274                 regs->ARM_r8);
 275         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 276                 regs->ARM_r7, regs->ARM_r6,
 277                 regs->ARM_r5, regs->ARM_r4);
 278         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 279                 regs->ARM_r3, regs->ARM_r2,
 280                 regs->ARM_r1, regs->ARM_r0);
 281
 282         flags = regs->ARM_cpsr;
 283         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 284         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 285         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 286         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 287         buf[4] = '\0';
 288
 289         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 290                 buf, interrupts_enabled(regs) ? "n" : "ff",
 291                 fast_interrupts_enabled(regs) ? "n" : "ff",
 292                 processor_modes[processor_mode(regs)],
 293                 isa_modes[isa_mode(regs)],
 294                 get_fs() == get_ds() ? "kernel" : "user");
 295 #ifdef CONFIG_CPU_CP15
 296         {
 297                 unsigned int ctrl;
 298
 299                 buf[0] = '\0';
 300 #ifdef CONFIG_CPU_CP15_MMU
 301                 {
 302                         unsigned int transbase, dac;
 303                         asm("mrc p15, 0, %0, c2, c0\n\t"
 304                             "mrc p15, 0, %1, c3, c0\n"
 305                             : "=r" (transbase), "=r" (dac));
 306                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 307                                 transbase, dac);
 308                 }
 309 #endif
 310                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 311
 312                 printk("Control: %08x%s\n", ctrl, buf);
 313         }
 314 #endif
 315 }
 316
 317 void show_regs(struct pt_regs * regs)
 318 {
 319         printk("\n");
 320         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 321         __show_regs(regs);
 322         __backtrace();
 323 }
 324
 325 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 326
 327 EXPORT_SYMBOL_GPL(thread_notify_head);
 328
 329 /*
 330  * Free current thread data structures etc..
 331  */
 332 void exit_thread(void)
 333 {
 334         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 335 }
 336
 337 void flush_thread(void)
 338 {
 339         struct thread_info *thread = current_thread_info();
 340         struct task_struct *tsk = current;
 341
 342         flush_ptrace_hw_breakpoint(tsk);
 343
 344         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 345         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 346         memset(&thread->fpstate, 0, sizeof(union fp_state));
 347
 348         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 349 }
 350
 351 void release_thread(struct task_struct *dead_task)
 352 {
 353 }
 354
 355 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 356
 357 int
 358 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 359             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 360 {
 361         struct thread_info *thread = task_thread_info(p);
 362         struct pt_regs *childregs = task_pt_regs(p);
 363
 364         *childregs = *regs;
 365         childregs->ARM_r0 = 0;
 366         childregs->ARM_sp = stack_start;
 367
 368         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 369         thread->cpu_context.sp = (unsigned long)childregs;
 370         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 371
 372         clear_ptrace_hw_breakpoint(p);
 373
 374         if (clone_flags & CLONE_SETTLS)
 375                 thread->tp_value = regs->ARM_r3;
 376
 377         thread_notify(THREAD_NOTIFY_COPY, thread);
 378
 379         return 0;
 380 }
 381
 382 /*
 383  * Fill in the task's elfregs structure for a core dump.
 384  */
 385 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 386 {
 387         elf_core_copy_regs(elfregs, task_pt_regs(t));
 388         return 1;
 389 }
 390
 391 /*
 392  * fill in the fpe structure for a core dump...
 393  */
 394 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 395 {
 396         struct thread_info *thread = current_thread_info();
 397         int used_math = thread->used_cp[1] | thread->used_cp[2];
 398
 399         if (used_math)
 400                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 401
 402         return used_math != 0;
 403 }
 404 EXPORT_SYMBOL(dump_fpu);
 405
 406 /*
 407  * Shuffle the argument into the correct register before calling the
 408  * thread function.  r4 is the thread argument, r5 is the pointer to
 409  * the thread function, and r6 points to the exit function.
 410  */
 411 extern void kernel_thread_helper(void);
 412 asm(    ".pushsection .text\n"
 413 "       .align\n"
 414 "       .type   kernel_thread_helper, #function\n"
 415 "kernel_thread_helper:\n"
 416 #ifdef CONFIG_TRACE_IRQFLAGS
 417 "       bl      trace_hardirqs_on\n"
 418 #endif
 419 "       msr     cpsr_c, r7\n"
 420 "       mov     r0, r4\n"
 421 "       mov     lr, r6\n"
 422 "       mov     pc, r5\n"
 423 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 424 "       .popsection");
 425
 426 #ifdef CONFIG_ARM_UNWIND
 427 extern void kernel_thread_exit(long code);
 428 asm(    ".pushsection .text\n"
 429 "       .align\n"
 430 "       .type   kernel_thread_exit, #function\n"
 431 "kernel_thread_exit:\n"
 432 "       .fnstart\n"
 433 "       .cantunwind\n"
 434 "       bl      do_exit\n"
 435 "       nop\n"
 436 "       .fnend\n"
 437 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 438 "       .popsection");
 439 #else
 440 #define kernel_thread_exit      do_exit
 441 #endif
 442
 443 /*
 444  * Create a kernel thread.
 445  */
 446 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 447 {
 448         struct pt_regs regs;
 449
 450         memset(&regs, 0, sizeof(regs));
 451
 452         regs.ARM_r4 = (unsigned long)arg;
 453         regs.ARM_r5 = (unsigned long)fn;
 454         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 455         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 456         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 457         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 458
 459         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 460 }
 461 EXPORT_SYMBOL(kernel_thread);
 462
 463 unsigned long get_wchan(struct task_struct *p)
 464 {
 465         struct stackframe frame;
 466         int count = 0;
 467         if (!p || p == current || p->state == TASK_RUNNING)
 468                 return 0;
 469
 470         frame.fp = thread_saved_fp(p);
 471         frame.sp = thread_saved_sp(p);
 472         frame.lr = 0;                   /* recovered from the stack */
 473         frame.pc = thread_saved_pc(p);
 474         do {
 475                 int ret = unwind_frame(&frame);
 476                 if (ret < 0)
 477                         return 0;
 478                 if (!in_sched_functions(frame.pc))
 479                         return frame.pc;
 480         } while (count ++ < 16);
 481         return 0;
 482 }
 483
 484 unsigned long arch_randomize_brk(struct mm_struct *mm)
 485 {
 486         unsigned long range_end = mm->brk + 0x02000000;
 487         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 488 }
 489
 490 #ifdef CONFIG_MMU
 491 /*
 492  * The vectors page is always readable from user space for the
 493  * atomic helpers and the signal restart code.  Let's declare a mapping
 494  * for it so it is visible through ptrace and /proc/<pid>/mem.
 495  */
 496
 497 int vectors_user_mapping(void)
 498 {
 499         struct mm_struct *mm = current->mm;
 500         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 501                                        VM_READ | VM_EXEC |
 502                                        VM_MAYREAD | VM_MAYEXEC |
 503                                        VM_ALWAYSDUMP | VM_RESERVED,
 504                                        NULL);
 505 }
 506
 507 const char *arch_vma_name(struct vm_area_struct *vma)
 508 {
 509         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 510 }
 511 #endif