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/export.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 #include <linux/leds.h>
  35
  36 #include <asm/cacheflush.h>
  37 #include <asm/idmap.h>
  38 #include <asm/processor.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 static volatile int hlt_counter;
  61
  62 void disable_hlt(void)
  63 {
  64         hlt_counter++;
  65 }
  66
  67 EXPORT_SYMBOL(disable_hlt);
  68
  69 void enable_hlt(void)
  70 {
  71         hlt_counter--;
  72         BUG_ON(hlt_counter < 0);
  73 }
  74
  75 EXPORT_SYMBOL(enable_hlt);
  76
  77 static int __init nohlt_setup(char *__unused)
  78 {
  79         hlt_counter = 1;
  80         return 1;
  81 }
  82
  83 static int __init hlt_setup(char *__unused)
  84 {
  85         hlt_counter = 0;
  86         return 1;
  87 }
  88
  89 __setup("nohlt", nohlt_setup);
  90 __setup("hlt", hlt_setup);
  91
  92 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
  93 typedef void (*phys_reset_t)(unsigned long);
  94
  95 /*
  96  * A temporary stack to use for CPU reset. This is static so that we
  97  * don't clobber it with the identity mapping. When running with this
  98  * stack, any references to the current task *will not work* so you
  99  * should really do as little as possible before jumping to your reset
 100  * code.
 101  */
 102 static u64 soft_restart_stack[16];
 103
 104 static void __soft_restart(void *addr)
 105 {
 106         phys_reset_t phys_reset;
 107
 108         /* Take out a flat memory mapping. */
 109         setup_mm_for_reboot();
 110
 111         /* Clean and invalidate caches */
 112         flush_cache_all();
 113
 114         /* Turn off caching */
 115         cpu_proc_fin();
 116
 117         /* Push out any further dirty data, and ensure cache is empty */
 118         flush_cache_all();
 119
 120         /* Switch to the identity mapping. */
 121         phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
 122         phys_reset((unsigned long)addr);
 123
 124         /* Should never get here. */
 125         BUG();
 126 }
 127
 128 void soft_restart(unsigned long addr)
 129 {
 130         u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
 131
 132         /* Disable interrupts first */
 133         local_irq_disable();
 134         local_fiq_disable();
 135
 136         /* Disable the L2 if we're the last man standing. */
 137         if (num_online_cpus() == 1)
 138                 outer_disable();
 139
 140         /* Change to the new stack and continue with the reset. */
 141         call_with_stack(__soft_restart, (void *)addr, (void *)stack);
 142
 143         /* Should never get here. */
 144         BUG();
 145 }
 146
 147 static void null_restart(char mode, const char *cmd)
 148 {
 149 }
 150
 151 /*
 152  * Function pointers to optional machine specific functions
 153  */
 154 void (*pm_power_off)(void);
 155 EXPORT_SYMBOL(pm_power_off);
 156
 157 void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
 158 EXPORT_SYMBOL_GPL(arm_pm_restart);
 159
 160 /*
 161  * This is our default idle handler.
 162  */
 163
 164 void (*arm_pm_idle)(void);
 165
 166 static void default_idle(void)
 167 {
 168         if (arm_pm_idle)
 169                 arm_pm_idle();
 170         else
 171                 cpu_do_idle();
 172         local_irq_enable();
 173 }
 174
 175 /*
 176  * The idle thread.
 177  * We always respect 'hlt_counter' to prevent low power idle.
 178  */
 179 void cpu_idle(void)
 180 {
 181         local_fiq_enable();
 182
 183         /* endless idle loop with no priority at all */
 184         while (1) {
 185                 tick_nohz_idle_enter();
 186                 rcu_idle_enter();
 187                 ledtrig_cpu(CPU_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                         /*
 195                          * We need to disable interrupts here
 196                          * to ensure we don't miss a wakeup call.
 197                          */
 198                         local_irq_disable();
 199 #ifdef CONFIG_PL310_ERRATA_769419
 200                         wmb();
 201 #endif
 202                         if (hlt_counter) {
 203                                 local_irq_enable();
 204                                 cpu_relax();
 205                         } else if (!need_resched()) {
 206                                 stop_critical_timings();
 207                                 if (cpuidle_idle_call())
 208                                         default_idle();
 209                                 start_critical_timings();
 210                                 /*
 211                                  * default_idle functions must always
 212                                  * return with IRQs enabled.
 213                                  */
 214                                 WARN_ON(irqs_disabled());
 215                         } else
 216                                 local_irq_enable();
 217                 }
 218                 ledtrig_cpu(CPU_LED_IDLE_END);
 219                 rcu_idle_exit();
 220                 tick_nohz_idle_exit();
 221                 schedule_preempt_disabled();
 222         }
 223 }
 224
 225 static char reboot_mode = 'h';
 226
 227 int __init reboot_setup(char *str)
 228 {
 229         reboot_mode = str[0];
 230         return 1;
 231 }
 232
 233 __setup("reboot=", reboot_setup);
 234
 235 void machine_shutdown(void)
 236 {
 237 #ifdef CONFIG_SMP
 238         smp_send_stop();
 239 #endif
 240 }
 241
 242 void machine_halt(void)
 243 {
 244         machine_shutdown();
 245         local_irq_disable();
 246         while (1);
 247 }
 248
 249 void machine_power_off(void)
 250 {
 251         machine_shutdown();
 252         if (pm_power_off)
 253                 pm_power_off();
 254 }
 255
 256 void machine_restart(char *cmd)
 257 {
 258         machine_shutdown();
 259
 260         arm_pm_restart(reboot_mode, cmd);
 261
 262         /* Give a grace period for failure to restart of 1s */
 263         mdelay(1000);
 264
 265         /* Whoops - the platform was unable to reboot. Tell the user! */
 266         printk("Reboot failed -- System halted\n");
 267         local_irq_disable();
 268         while (1);
 269 }
 270
 271 void __show_regs(struct pt_regs *regs)
 272 {
 273         unsigned long flags;
 274         char buf[64];
 275
 276         printk("CPU: %d    %s  (%s %.*s)\n",
 277                 raw_smp_processor_id(), print_tainted(),
 278                 init_utsname()->release,
 279                 (int)strcspn(init_utsname()->version, " "),
 280                 init_utsname()->version);
 281         print_symbol("PC is at %s\n", instruction_pointer(regs));
 282         print_symbol("LR is at %s\n", regs->ARM_lr);
 283         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 284                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 285                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 286                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 287         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 288                 regs->ARM_r10, regs->ARM_r9,
 289                 regs->ARM_r8);
 290         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 291                 regs->ARM_r7, regs->ARM_r6,
 292                 regs->ARM_r5, regs->ARM_r4);
 293         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 294                 regs->ARM_r3, regs->ARM_r2,
 295                 regs->ARM_r1, regs->ARM_r0);
 296
 297         flags = regs->ARM_cpsr;
 298         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 299         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 300         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 301         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 302         buf[4] = '\0';
 303
 304         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 305                 buf, interrupts_enabled(regs) ? "n" : "ff",
 306                 fast_interrupts_enabled(regs) ? "n" : "ff",
 307                 processor_modes[processor_mode(regs)],
 308                 isa_modes[isa_mode(regs)],
 309                 get_fs() == get_ds() ? "kernel" : "user");
 310 #ifdef CONFIG_CPU_CP15
 311         {
 312                 unsigned int ctrl;
 313
 314                 buf[0] = '\0';
 315 #ifdef CONFIG_CPU_CP15_MMU
 316                 {
 317                         unsigned int transbase, dac;
 318                         asm("mrc p15, 0, %0, c2, c0\n\t"
 319                             "mrc p15, 0, %1, c3, c0\n"
 320                             : "=r" (transbase), "=r" (dac));
 321                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 322                                 transbase, dac);
 323                 }
 324 #endif
 325                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 326
 327                 printk("Control: %08x%s\n", ctrl, buf);
 328         }
 329 #endif
 330 }
 331
 332 void show_regs(struct pt_regs * regs)
 333 {
 334         printk("\n");
 335         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 336         __show_regs(regs);
 337         dump_stack();
 338 }
 339
 340 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 341
 342 EXPORT_SYMBOL_GPL(thread_notify_head);
 343
 344 /*
 345  * Free current thread data structures etc..
 346  */
 347 void exit_thread(void)
 348 {
 349         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 350 }
 351
 352 void flush_thread(void)
 353 {
 354         struct thread_info *thread = current_thread_info();
 355         struct task_struct *tsk = current;
 356
 357         flush_ptrace_hw_breakpoint(tsk);
 358
 359         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 360         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 361         memset(&thread->fpstate, 0, sizeof(union fp_state));
 362
 363         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 364 }
 365
 366 void release_thread(struct task_struct *dead_task)
 367 {
 368 }
 369
 370 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 371
 372 int
 373 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 374             unsigned long stk_sz, struct task_struct *p)
 375 {
 376         struct thread_info *thread = task_thread_info(p);
 377         struct pt_regs *childregs = task_pt_regs(p);
 378
 379         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 380
 381         if (likely(!(p->flags & PF_KTHREAD))) {
 382                 *childregs = *current_pt_regs();
 383                 childregs->ARM_r0 = 0;
 384                 if (stack_start)
 385                         childregs->ARM_sp = stack_start;
 386         } else {
 387                 memset(childregs, 0, sizeof(struct pt_regs));
 388                 thread->cpu_context.r4 = stk_sz;
 389                 thread->cpu_context.r5 = stack_start;
 390                 childregs->ARM_cpsr = SVC_MODE;
 391         }
 392         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 393         thread->cpu_context.sp = (unsigned long)childregs;
 394
 395         clear_ptrace_hw_breakpoint(p);
 396
 397         if (clone_flags & CLONE_SETTLS)
 398                 thread->tp_value = childregs->ARM_r3;
 399
 400         thread_notify(THREAD_NOTIFY_COPY, thread);
 401
 402         return 0;
 403 }
 404
 405 /*
 406  * Fill in the task's elfregs structure for a core dump.
 407  */
 408 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 409 {
 410         elf_core_copy_regs(elfregs, task_pt_regs(t));
 411         return 1;
 412 }
 413
 414 /*
 415  * fill in the fpe structure for a core dump...
 416  */
 417 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 418 {
 419         struct thread_info *thread = current_thread_info();
 420         int used_math = thread->used_cp[1] | thread->used_cp[2];
 421
 422         if (used_math)
 423                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 424
 425         return used_math != 0;
 426 }
 427 EXPORT_SYMBOL(dump_fpu);
 428
 429 unsigned long get_wchan(struct task_struct *p)
 430 {
 431         struct stackframe frame;
 432         int count = 0;
 433         if (!p || p == current || p->state == TASK_RUNNING)
 434                 return 0;
 435
 436         frame.fp = thread_saved_fp(p);
 437         frame.sp = thread_saved_sp(p);
 438         frame.lr = 0;                   /* recovered from the stack */
 439         frame.pc = thread_saved_pc(p);
 440         do {
 441                 int ret = unwind_frame(&frame);
 442                 if (ret < 0)
 443                         return 0;
 444                 if (!in_sched_functions(frame.pc))
 445                         return frame.pc;
 446         } while (count ++ < 16);
 447         return 0;
 448 }
 449
 450 unsigned long arch_randomize_brk(struct mm_struct *mm)
 451 {
 452         unsigned long range_end = mm->brk + 0x02000000;
 453         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 454 }
 455
 456 #ifdef CONFIG_MMU
 457 /*
 458  * The vectors page is always readable from user space for the
 459  * atomic helpers and the signal restart code. Insert it into the
 460  * gate_vma so that it is visible through ptrace and /proc/<pid>/mem.
 461  */
 462 static struct vm_area_struct gate_vma = {
 463         .vm_start       = 0xffff0000,
 464         .vm_end         = 0xffff0000 + PAGE_SIZE,
 465         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 466         .vm_mm          = &init_mm,
 467 };
 468
 469 static int __init gate_vma_init(void)
 470 {
 471         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 472         return 0;
 473 }
 474 arch_initcall(gate_vma_init);
 475
 476 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 477 {
 478         return &gate_vma;
 479 }
 480
 481 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 482 {
 483         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 484 }
 485
 486 int in_gate_area_no_mm(unsigned long addr)
 487 {
 488         return in_gate_area(NULL, addr);
 489 }
 490
 491 const char *arch_vma_name(struct vm_area_struct *vma)
 492 {
 493         return (vma == &gate_vma) ? "[vectors]" : NULL;
 494 }
 495 #endif