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 #include <linux/reboot.h>
  36
  37 #include <asm/cacheflush.h>
  38 #include <asm/idmap.h>
  39 #include <asm/processor.h>
  40 #include <asm/thread_notify.h>
  41 #include <asm/stacktrace.h>
  42 #include <asm/mach/time.h>
  43 #include <asm/tls.h>
  44
  45 #ifdef CONFIG_CC_STACKPROTECTOR
  46 #include <linux/stackprotector.h>
  47 unsigned long __stack_chk_guard __read_mostly;
  48 EXPORT_SYMBOL(__stack_chk_guard);
  49 #endif
  50
  51 static const char *processor_modes[] = {
  52   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  53   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  54   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  55   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  56 };
  57
  58 static const char *isa_modes[] = {
  59   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  60 };
  61
  62 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
  63 typedef void (*phys_reset_t)(unsigned long);
  64
  65 /*
  66  * A temporary stack to use for CPU reset. This is static so that we
  67  * don't clobber it with the identity mapping. When running with this
  68  * stack, any references to the current task *will not work* so you
  69  * should really do as little as possible before jumping to your reset
  70  * code.
  71  */
  72 static u64 soft_restart_stack[16];
  73
  74 static void __soft_restart(void *addr)
  75 {
  76         phys_reset_t phys_reset;
  77
  78         /* Take out a flat memory mapping. */
  79         setup_mm_for_reboot();
  80
  81         /* Clean and invalidate caches */
  82         flush_cache_all();
  83
  84         /* Turn off caching */
  85         cpu_proc_fin();
  86
  87         /* Push out any further dirty data, and ensure cache is empty */
  88         flush_cache_all();
  89
  90         /* Switch to the identity mapping. */
  91         phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
  92         phys_reset((unsigned long)addr);
  93
  94         /* Should never get here. */
  95         BUG();
  96 }
  97
  98 void soft_restart(unsigned long addr)
  99 {
 100         u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
 101
 102         /* Disable interrupts first */
 103         local_irq_disable();
 104         local_fiq_disable();
 105
 106         /* Disable the L2 if we're the last man standing. */
 107         if (num_online_cpus() == 1)
 108                 outer_disable();
 109
 110         /* Change to the new stack and continue with the reset. */
 111         call_with_stack(__soft_restart, (void *)addr, (void *)stack);
 112
 113         /* Should never get here. */
 114         BUG();
 115 }
 116
 117 static void null_restart(enum reboot_mode reboot_mode, const char *cmd)
 118 {
 119 }
 120
 121 /*
 122  * Function pointers to optional machine specific functions
 123  */
 124 void (*pm_power_off)(void);
 125 EXPORT_SYMBOL(pm_power_off);
 126
 127 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd) = null_restart;
 128 EXPORT_SYMBOL_GPL(arm_pm_restart);
 129
 130 /*
 131  * This is our default idle handler.
 132  */
 133
 134 void (*arm_pm_idle)(void);
 135
 136 static void default_idle(void)
 137 {
 138         if (arm_pm_idle)
 139                 arm_pm_idle();
 140         else
 141                 cpu_do_idle();
 142         local_irq_enable();
 143 }
 144
 145 void arch_cpu_idle_prepare(void)
 146 {
 147         local_fiq_enable();
 148 }
 149
 150 void arch_cpu_idle_enter(void)
 151 {
 152         ledtrig_cpu(CPU_LED_IDLE_START);
 153 #ifdef CONFIG_PL310_ERRATA_769419
 154         wmb();
 155 #endif
 156 }
 157
 158 void arch_cpu_idle_exit(void)
 159 {
 160         ledtrig_cpu(CPU_LED_IDLE_END);
 161 }
 162
 163 #ifdef CONFIG_HOTPLUG_CPU
 164 void arch_cpu_idle_dead(void)
 165 {
 166         cpu_die();
 167 }
 168 #endif
 169
 170 /*
 171  * Called from the core idle loop.
 172  */
 173 void arch_cpu_idle(void)
 174 {
 175         if (cpuidle_idle_call())
 176                 default_idle();
 177 }
 178
 179 /*
 180  * Called by kexec, immediately prior to machine_kexec().
 181  *
 182  * This must completely disable all secondary CPUs; simply causing those CPUs
 183  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
 184  * kexec'd kernel to use any and all RAM as it sees fit, without having to
 185  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
 186  * functionality embodied in disable_nonboot_cpus() to achieve this.
 187  */
 188 void machine_shutdown(void)
 189 {
 190         disable_nonboot_cpus();
 191 }
 192
 193 /*
 194  * Halting simply requires that the secondary CPUs stop performing any
 195  * activity (executing tasks, handling interrupts). smp_send_stop()
 196  * achieves this.
 197  */
 198 void machine_halt(void)
 199 {
 200         local_irq_disable();
 201         smp_send_stop();
 202
 203         local_irq_disable();
 204         while (1);
 205 }
 206
 207 /*
 208  * Power-off simply requires that the secondary CPUs stop performing any
 209  * activity (executing tasks, handling interrupts). smp_send_stop()
 210  * achieves this. When the system power is turned off, it will take all CPUs
 211  * with it.
 212  */
 213 void machine_power_off(void)
 214 {
 215         local_irq_disable();
 216         smp_send_stop();
 217
 218         if (pm_power_off)
 219                 pm_power_off();
 220 }
 221
 222 /*
 223  * Restart requires that the secondary CPUs stop performing any activity
 224  * while the primary CPU resets the system. Systems with a single CPU can
 225  * use soft_restart() as their machine descriptor's .restart hook, since that
 226  * will cause the only available CPU to reset. Systems with multiple CPUs must
 227  * provide a HW restart implementation, to ensure that all CPUs reset at once.
 228  * This is required so that any code running after reset on the primary CPU
 229  * doesn't have to co-ordinate with other CPUs to ensure they aren't still
 230  * executing pre-reset code, and using RAM that the primary CPU's code wishes
 231  * to use. Implementing such co-ordination would be essentially impossible.
 232  */
 233 void machine_restart(char *cmd)
 234 {
 235         local_irq_disable();
 236         smp_send_stop();
 237
 238         arm_pm_restart(reboot_mode, cmd);
 239
 240         /* Give a grace period for failure to restart of 1s */
 241         mdelay(1000);
 242
 243         /* Whoops - the platform was unable to reboot. Tell the user! */
 244         printk("Reboot failed -- System halted\n");
 245         local_irq_disable();
 246         while (1);
 247 }
 248
 249 void __show_regs(struct pt_regs *regs)
 250 {
 251         unsigned long flags;
 252         char buf[64];
 253
 254         show_regs_print_info(KERN_DEFAULT);
 255
 256         print_symbol("PC is at %s\n", instruction_pointer(regs));
 257         print_symbol("LR is at %s\n", regs->ARM_lr);
 258         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 259                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 260                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 261                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 262         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 263                 regs->ARM_r10, regs->ARM_r9,
 264                 regs->ARM_r8);
 265         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 266                 regs->ARM_r7, regs->ARM_r6,
 267                 regs->ARM_r5, regs->ARM_r4);
 268         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 269                 regs->ARM_r3, regs->ARM_r2,
 270                 regs->ARM_r1, regs->ARM_r0);
 271
 272         flags = regs->ARM_cpsr;
 273         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 274         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 275         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 276         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 277         buf[4] = '\0';
 278
 279         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 280                 buf, interrupts_enabled(regs) ? "n" : "ff",
 281                 fast_interrupts_enabled(regs) ? "n" : "ff",
 282                 processor_modes[processor_mode(regs)],
 283                 isa_modes[isa_mode(regs)],
 284                 get_fs() == get_ds() ? "kernel" : "user");
 285 #ifdef CONFIG_CPU_CP15
 286         {
 287                 unsigned int ctrl;
 288
 289                 buf[0] = '\0';
 290 #ifdef CONFIG_CPU_CP15_MMU
 291                 {
 292                         unsigned int transbase, dac;
 293                         asm("mrc p15, 0, %0, c2, c0\n\t"
 294                             "mrc p15, 0, %1, c3, c0\n"
 295                             : "=r" (transbase), "=r" (dac));
 296                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 297                                 transbase, dac);
 298                 }
 299 #endif
 300                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 301
 302                 printk("Control: %08x%s\n", ctrl, buf);
 303         }
 304 #endif
 305 }
 306
 307 void show_regs(struct pt_regs * regs)
 308 {
 309         printk("\n");
 310         __show_regs(regs);
 311         dump_stack();
 312 }
 313
 314 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 315
 316 EXPORT_SYMBOL_GPL(thread_notify_head);
 317
 318 /*
 319  * Free current thread data structures etc..
 320  */
 321 void exit_thread(void)
 322 {
 323         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 324 }
 325
 326 void flush_thread(void)
 327 {
 328         struct thread_info *thread = current_thread_info();
 329         struct task_struct *tsk = current;
 330
 331         flush_ptrace_hw_breakpoint(tsk);
 332
 333         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 334         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 335         memset(&thread->fpstate, 0, sizeof(union fp_state));
 336
 337         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 338 }
 339
 340 void release_thread(struct task_struct *dead_task)
 341 {
 342 }
 343
 344 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 345
 346 int
 347 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 348             unsigned long stk_sz, struct task_struct *p)
 349 {
 350         struct thread_info *thread = task_thread_info(p);
 351         struct pt_regs *childregs = task_pt_regs(p);
 352
 353         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 354
 355         if (likely(!(p->flags & PF_KTHREAD))) {
 356                 *childregs = *current_pt_regs();
 357                 childregs->ARM_r0 = 0;
 358                 if (stack_start)
 359                         childregs->ARM_sp = stack_start;
 360         } else {
 361                 memset(childregs, 0, sizeof(struct pt_regs));
 362                 thread->cpu_context.r4 = stk_sz;
 363                 thread->cpu_context.r5 = stack_start;
 364                 childregs->ARM_cpsr = SVC_MODE;
 365         }
 366         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 367         thread->cpu_context.sp = (unsigned long)childregs;
 368
 369         clear_ptrace_hw_breakpoint(p);
 370
 371         if (clone_flags & CLONE_SETTLS)
 372                 thread->tp_value[0] = childregs->ARM_r3;
 373         thread->tp_value[1] = get_tpuser();
 374
 375         thread_notify(THREAD_NOTIFY_COPY, thread);
 376
 377         return 0;
 378 }
 379
 380 /*
 381  * Fill in the task's elfregs structure for a core dump.
 382  */
 383 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 384 {
 385         elf_core_copy_regs(elfregs, task_pt_regs(t));
 386         return 1;
 387 }
 388
 389 /*
 390  * fill in the fpe structure for a core dump...
 391  */
 392 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 393 {
 394         struct thread_info *thread = current_thread_info();
 395         int used_math = thread->used_cp[1] | thread->used_cp[2];
 396
 397         if (used_math)
 398                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 399
 400         return used_math != 0;
 401 }
 402 EXPORT_SYMBOL(dump_fpu);
 403
 404 unsigned long get_wchan(struct task_struct *p)
 405 {
 406         struct stackframe frame;
 407         int count = 0;
 408         if (!p || p == current || p->state == TASK_RUNNING)
 409                 return 0;
 410
 411         frame.fp = thread_saved_fp(p);
 412         frame.sp = thread_saved_sp(p);
 413         frame.lr = 0;                   /* recovered from the stack */
 414         frame.pc = thread_saved_pc(p);
 415         do {
 416                 int ret = unwind_frame(&frame);
 417                 if (ret < 0)
 418                         return 0;
 419                 if (!in_sched_functions(frame.pc))
 420                         return frame.pc;
 421         } while (count ++ < 16);
 422         return 0;
 423 }
 424
 425 unsigned long arch_randomize_brk(struct mm_struct *mm)
 426 {
 427         unsigned long range_end = mm->brk + 0x02000000;
 428         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 429 }
 430
 431 #ifdef CONFIG_MMU
 432 /*
 433  * The vectors page is always readable from user space for the
 434  * atomic helpers and the signal restart code. Insert it into the
 435  * gate_vma so that it is visible through ptrace and /proc/<pid>/mem.
 436  */
 437 static struct vm_area_struct gate_vma = {
 438         .vm_start       = 0xffff0000,
 439         .vm_end         = 0xffff0000 + PAGE_SIZE,
 440         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 441 };
 442
 443 static int __init gate_vma_init(void)
 444 {
 445         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 446         return 0;
 447 }
 448 arch_initcall(gate_vma_init);
 449
 450 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 451 {
 452         return &gate_vma;
 453 }
 454
 455 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 456 {
 457         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 458 }
 459
 460 int in_gate_area_no_mm(unsigned long addr)
 461 {
 462         return in_gate_area(NULL, addr);
 463 }
 464
 465 const char *arch_vma_name(struct vm_area_struct *vma)
 466 {
 467         return (vma == &gate_vma) ? "[vectors]" : NULL;
 468 }
 469 #endif