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 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
  61 typedef void (*phys_reset_t)(unsigned long);
  62
  63 /*
  64  * A temporary stack to use for CPU reset. This is static so that we
  65  * don't clobber it with the identity mapping. When running with this
  66  * stack, any references to the current task *will not work* so you
  67  * should really do as little as possible before jumping to your reset
  68  * code.
  69  */
  70 static u64 soft_restart_stack[16];
  71
  72 static void __soft_restart(void *addr)
  73 {
  74         phys_reset_t phys_reset;
  75
  76         /* Take out a flat memory mapping. */
  77         setup_mm_for_reboot();
  78
  79         /* Clean and invalidate caches */
  80         flush_cache_all();
  81
  82         /* Turn off caching */
  83         cpu_proc_fin();
  84
  85         /* Push out any further dirty data, and ensure cache is empty */
  86         flush_cache_all();
  87
  88         /* Switch to the identity mapping. */
  89         phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
  90         phys_reset((unsigned long)addr);
  91
  92         /* Should never get here. */
  93         BUG();
  94 }
  95
  96 void soft_restart(unsigned long addr)
  97 {
  98         u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
  99
 100         /* Disable interrupts first */
 101         local_irq_disable();
 102         local_fiq_disable();
 103
 104         /* Disable the L2 if we're the last man standing. */
 105         if (num_online_cpus() == 1)
 106                 outer_disable();
 107
 108         /* Change to the new stack and continue with the reset. */
 109         call_with_stack(__soft_restart, (void *)addr, (void *)stack);
 110
 111         /* Should never get here. */
 112         BUG();
 113 }
 114
 115 static void null_restart(char mode, const char *cmd)
 116 {
 117 }
 118
 119 /*
 120  * Function pointers to optional machine specific functions
 121  */
 122 void (*pm_power_off)(void);
 123 EXPORT_SYMBOL(pm_power_off);
 124
 125 void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
 126 EXPORT_SYMBOL_GPL(arm_pm_restart);
 127
 128 /*
 129  * This is our default idle handler.
 130  */
 131
 132 void (*arm_pm_idle)(void);
 133
 134 static void default_idle(void)
 135 {
 136         if (arm_pm_idle)
 137                 arm_pm_idle();
 138         else
 139                 cpu_do_idle();
 140         local_irq_enable();
 141 }
 142
 143 void arch_cpu_idle_prepare(void)
 144 {
 145         local_fiq_enable();
 146 }
 147
 148 void arch_cpu_idle_enter(void)
 149 {
 150         ledtrig_cpu(CPU_LED_IDLE_START);
 151 #ifdef CONFIG_PL310_ERRATA_769419
 152         wmb();
 153 #endif
 154 }
 155
 156 void arch_cpu_idle_exit(void)
 157 {
 158         ledtrig_cpu(CPU_LED_IDLE_END);
 159 }
 160
 161 #ifdef CONFIG_HOTPLUG_CPU
 162 void arch_cpu_idle_dead(void)
 163 {
 164         cpu_die();
 165 }
 166 #endif
 167
 168 /*
 169  * Called from the core idle loop.
 170  */
 171 void arch_cpu_idle(void)
 172 {
 173         if (cpuidle_idle_call())
 174                 default_idle();
 175 }
 176
 177 static char reboot_mode = 'h';
 178
 179 int __init reboot_setup(char *str)
 180 {
 181         reboot_mode = str[0];
 182         return 1;
 183 }
 184
 185 __setup("reboot=", reboot_setup);
 186
 187 /*
 188  * Called by kexec, immediately prior to machine_kexec().
 189  *
 190  * This must completely disable all secondary CPUs; simply causing those CPUs
 191  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
 192  * kexec'd kernel to use any and all RAM as it sees fit, without having to
 193  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
 194  * functionality embodied in disable_nonboot_cpus() to achieve this.
 195  */
 196 void machine_shutdown(void)
 197 {
 198         disable_nonboot_cpus();
 199 }
 200
 201 /*
 202  * Halting simply requires that the secondary CPUs stop performing any
 203  * activity (executing tasks, handling interrupts). smp_send_stop()
 204  * achieves this.
 205  */
 206 void machine_halt(void)
 207 {
 208         smp_send_stop();
 209
 210         local_irq_disable();
 211         while (1);
 212 }
 213
 214 /*
 215  * Power-off simply requires that the secondary CPUs stop performing any
 216  * activity (executing tasks, handling interrupts). smp_send_stop()
 217  * achieves this. When the system power is turned off, it will take all CPUs
 218  * with it.
 219  */
 220 void machine_power_off(void)
 221 {
 222         smp_send_stop();
 223
 224         if (pm_power_off)
 225                 pm_power_off();
 226 }
 227
 228 /*
 229  * Restart requires that the secondary CPUs stop performing any activity
 230  * while the primary CPU resets the system. Systems with a single CPU can
 231  * use soft_restart() as their machine descriptor's .restart hook, since that
 232  * will cause the only available CPU to reset. Systems with multiple CPUs must
 233  * provide a HW restart implementation, to ensure that all CPUs reset at once.
 234  * This is required so that any code running after reset on the primary CPU
 235  * doesn't have to co-ordinate with other CPUs to ensure they aren't still
 236  * executing pre-reset code, and using RAM that the primary CPU's code wishes
 237  * to use. Implementing such co-ordination would be essentially impossible.
 238  */
 239 void machine_restart(char *cmd)
 240 {
 241         smp_send_stop();
 242
 243         arm_pm_restart(reboot_mode, cmd);
 244
 245         /* Give a grace period for failure to restart of 1s */
 246         mdelay(1000);
 247
 248         /* Whoops - the platform was unable to reboot. Tell the user! */
 249         printk("Reboot failed -- System halted\n");
 250         local_irq_disable();
 251         while (1);
 252 }
 253
 254 void __show_regs(struct pt_regs *regs)
 255 {
 256         unsigned long flags;
 257         char buf[64];
 258
 259         show_regs_print_info(KERN_DEFAULT);
 260
 261         print_symbol("PC is at %s\n", instruction_pointer(regs));
 262         print_symbol("LR is at %s\n", regs->ARM_lr);
 263         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 264                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 265                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 266                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 267         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 268                 regs->ARM_r10, regs->ARM_r9,
 269                 regs->ARM_r8);
 270         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 271                 regs->ARM_r7, regs->ARM_r6,
 272                 regs->ARM_r5, regs->ARM_r4);
 273         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 274                 regs->ARM_r3, regs->ARM_r2,
 275                 regs->ARM_r1, regs->ARM_r0);
 276
 277         flags = regs->ARM_cpsr;
 278         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 279         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 280         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 281         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 282         buf[4] = '\0';
 283
 284         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 285                 buf, interrupts_enabled(regs) ? "n" : "ff",
 286                 fast_interrupts_enabled(regs) ? "n" : "ff",
 287                 processor_modes[processor_mode(regs)],
 288                 isa_modes[isa_mode(regs)],
 289                 get_fs() == get_ds() ? "kernel" : "user");
 290 #ifdef CONFIG_CPU_CP15
 291         {
 292                 unsigned int ctrl;
 293
 294                 buf[0] = '\0';
 295 #ifdef CONFIG_CPU_CP15_MMU
 296                 {
 297                         unsigned int transbase, dac;
 298                         asm("mrc p15, 0, %0, c2, c0\n\t"
 299                             "mrc p15, 0, %1, c3, c0\n"
 300                             : "=r" (transbase), "=r" (dac));
 301                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 302                                 transbase, dac);
 303                 }
 304 #endif
 305                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 306
 307                 printk("Control: %08x%s\n", ctrl, buf);
 308         }
 309 #endif
 310 }
 311
 312 void show_regs(struct pt_regs * regs)
 313 {
 314         printk("\n");
 315         __show_regs(regs);
 316         dump_stack();
 317 }
 318
 319 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 320
 321 EXPORT_SYMBOL_GPL(thread_notify_head);
 322
 323 /*
 324  * Free current thread data structures etc..
 325  */
 326 void exit_thread(void)
 327 {
 328         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 329 }
 330
 331 void flush_thread(void)
 332 {
 333         struct thread_info *thread = current_thread_info();
 334         struct task_struct *tsk = current;
 335
 336         flush_ptrace_hw_breakpoint(tsk);
 337
 338         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 339         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 340         memset(&thread->fpstate, 0, sizeof(union fp_state));
 341
 342         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 343 }
 344
 345 void release_thread(struct task_struct *dead_task)
 346 {
 347 }
 348
 349 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 350
 351 int
 352 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 353             unsigned long stk_sz, struct task_struct *p)
 354 {
 355         struct thread_info *thread = task_thread_info(p);
 356         struct pt_regs *childregs = task_pt_regs(p);
 357
 358         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 359
 360         if (likely(!(p->flags & PF_KTHREAD))) {
 361                 *childregs = *current_pt_regs();
 362                 childregs->ARM_r0 = 0;
 363                 if (stack_start)
 364                         childregs->ARM_sp = stack_start;
 365         } else {
 366                 memset(childregs, 0, sizeof(struct pt_regs));
 367                 thread->cpu_context.r4 = stk_sz;
 368                 thread->cpu_context.r5 = stack_start;
 369                 childregs->ARM_cpsr = SVC_MODE;
 370         }
 371         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 372         thread->cpu_context.sp = (unsigned long)childregs;
 373
 374         clear_ptrace_hw_breakpoint(p);
 375
 376         if (clone_flags & CLONE_SETTLS)
 377                 thread->tp_value = childregs->ARM_r3;
 378
 379         thread_notify(THREAD_NOTIFY_COPY, thread);
 380
 381         return 0;
 382 }
 383
 384 /*
 385  * Fill in the task's elfregs structure for a core dump.
 386  */
 387 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 388 {
 389         elf_core_copy_regs(elfregs, task_pt_regs(t));
 390         return 1;
 391 }
 392
 393 /*
 394  * fill in the fpe structure for a core dump...
 395  */
 396 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 397 {
 398         struct thread_info *thread = current_thread_info();
 399         int used_math = thread->used_cp[1] | thread->used_cp[2];
 400
 401         if (used_math)
 402                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 403
 404         return used_math != 0;
 405 }
 406 EXPORT_SYMBOL(dump_fpu);
 407
 408 unsigned long get_wchan(struct task_struct *p)
 409 {
 410         struct stackframe frame;
 411         int count = 0;
 412         if (!p || p == current || p->state == TASK_RUNNING)
 413                 return 0;
 414
 415         frame.fp = thread_saved_fp(p);
 416         frame.sp = thread_saved_sp(p);
 417         frame.lr = 0;                   /* recovered from the stack */
 418         frame.pc = thread_saved_pc(p);
 419         do {
 420                 int ret = unwind_frame(&frame);
 421                 if (ret < 0)
 422                         return 0;
 423                 if (!in_sched_functions(frame.pc))
 424                         return frame.pc;
 425         } while (count ++ < 16);
 426         return 0;
 427 }
 428
 429 unsigned long arch_randomize_brk(struct mm_struct *mm)
 430 {
 431         unsigned long range_end = mm->brk + 0x02000000;
 432         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 433 }
 434
 435 #ifdef CONFIG_MMU
 436 /*
 437  * The vectors page is always readable from user space for the
 438  * atomic helpers and the signal restart code. Insert it into the
 439  * gate_vma so that it is visible through ptrace and /proc/<pid>/mem.
 440  */
 441 static struct vm_area_struct gate_vma = {
 442         .vm_start       = 0xffff0000,
 443         .vm_end         = 0xffff0000 + PAGE_SIZE,
 444         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 445 };
 446
 447 static int __init gate_vma_init(void)
 448 {
 449         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 450         return 0;
 451 }
 452 arch_initcall(gate_vma_init);
 453
 454 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 455 {
 456         return &gate_vma;
 457 }
 458
 459 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 460 {
 461         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 462 }
 463
 464 int in_gate_area_no_mm(unsigned long addr)
 465 {
 466         return in_gate_area(NULL, addr);
 467 }
 468
 469 const char *arch_vma_name(struct vm_area_struct *vma)
 470 {
 471         return (vma == &gate_vma) ? "[vectors]" : NULL;
 472 }
 473 #endif