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/slab.h>
  20 #include <linux/user.h>
  21 #include <linux/delay.h>
  22 #include <linux/reboot.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/kallsyms.h>
  25 #include <linux/init.h>
  26 #include <linux/cpu.h>
  27 #include <linux/elfcore.h>
  28 #include <linux/pm.h>
  29 #include <linux/tick.h>
  30 #include <linux/utsname.h>
  31 #include <linux/uaccess.h>
  32
  33 #include <asm/leds.h>
  34 #include <asm/processor.h>
  35 #include <asm/system.h>
  36 #include <asm/thread_notify.h>
  37 #include <asm/stacktrace.h>
  38 #include <asm/mach/time.h>
  39
  40 static const char *processor_modes[] = {
  41   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  42   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  43   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  44   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  45 };
  46
  47 static const char *isa_modes[] = {
  48   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  49 };
  50
  51 extern void setup_mm_for_reboot(char mode);
  52
  53 static volatile int hlt_counter;
  54
  55 #include <mach/system.h>
  56
  57 void disable_hlt(void)
  58 {
  59         hlt_counter++;
  60 }
  61
  62 EXPORT_SYMBOL(disable_hlt);
  63
  64 void enable_hlt(void)
  65 {
  66         hlt_counter--;
  67 }
  68
  69 EXPORT_SYMBOL(enable_hlt);
  70
  71 static int __init nohlt_setup(char *__unused)
  72 {
  73         hlt_counter = 1;
  74         return 1;
  75 }
  76
  77 static int __init hlt_setup(char *__unused)
  78 {
  79         hlt_counter = 0;
  80         return 1;
  81 }
  82
  83 __setup("nohlt", nohlt_setup);
  84 __setup("hlt", hlt_setup);
  85
  86 void arm_machine_restart(char mode, const char *cmd)
  87 {
  88         /*
  89          * Clean and disable cache, and turn off interrupts
  90          */
  91         cpu_proc_fin();
  92
  93         /*
  94          * Tell the mm system that we are going to reboot -
  95          * we may need it to insert some 1:1 mappings so that
  96          * soft boot works.
  97          */
  98         setup_mm_for_reboot(mode);
  99
 100         /*
 101          * Now call the architecture specific reboot code.
 102          */
 103         arch_reset(mode, cmd);
 104
 105         /*
 106          * Whoops - the architecture was unable to reboot.
 107          * Tell the user!
 108          */
 109         mdelay(1000);
 110         printk("Reboot failed -- System halted\n");
 111         while (1);
 112 }
 113
 114 /*
 115  * Function pointers to optional machine specific functions
 116  */
 117 void (*pm_idle)(void);
 118 EXPORT_SYMBOL(pm_idle);
 119
 120 void (*pm_power_off)(void);
 121 EXPORT_SYMBOL(pm_power_off);
 122
 123 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 124 EXPORT_SYMBOL_GPL(arm_pm_restart);
 125
 126
 127 /*
 128  * This is our default idle handler.  We need to disable
 129  * interrupts here to ensure we don't miss a wakeup call.
 130  */
 131 static void default_idle(void)
 132 {
 133         if (hlt_counter)
 134                 cpu_relax();
 135         else {
 136                 local_irq_disable();
 137                 if (!need_resched())
 138                         arch_idle();
 139                 local_irq_enable();
 140         }
 141 }
 142
 143 /*
 144  * The idle thread.  We try to conserve power, while trying to keep
 145  * overall latency low.  The architecture specific idle is passed
 146  * a value to indicate the level of "idleness" of the system.
 147  */
 148 void cpu_idle(void)
 149 {
 150         local_fiq_enable();
 151
 152         /* endless idle loop with no priority at all */
 153         while (1) {
 154                 void (*idle)(void) = pm_idle;
 155
 156 #ifdef CONFIG_HOTPLUG_CPU
 157                 if (cpu_is_offline(smp_processor_id())) {
 158                         leds_event(led_idle_start);
 159                         cpu_die();
 160                 }
 161 #endif
 162
 163                 if (!idle)
 164                         idle = default_idle;
 165                 leds_event(led_idle_start);
 166                 tick_nohz_stop_sched_tick(1);
 167                 while (!need_resched())
 168                         idle();
 169                 leds_event(led_idle_end);
 170                 tick_nohz_restart_sched_tick();
 171                 preempt_enable_no_resched();
 172                 schedule();
 173                 preempt_disable();
 174         }
 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 void machine_halt(void)
 188 {
 189 }
 190
 191
 192 void machine_power_off(void)
 193 {
 194         if (pm_power_off)
 195                 pm_power_off();
 196 }
 197
 198 void machine_restart(char *cmd)
 199 {
 200         arm_pm_restart(reboot_mode, cmd);
 201 }
 202
 203 void __show_regs(struct pt_regs *regs)
 204 {
 205         unsigned long flags;
 206         char buf[64];
 207
 208         printk("CPU: %d    %s  (%s %.*s)\n",
 209                 smp_processor_id(), print_tainted(), init_utsname()->release,
 210                 (int)strcspn(init_utsname()->version, " "),
 211                 init_utsname()->version);
 212         print_symbol("PC is at %s\n", instruction_pointer(regs));
 213         print_symbol("LR is at %s\n", regs->ARM_lr);
 214         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 215                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 216                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 217                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 218         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 219                 regs->ARM_r10, regs->ARM_r9,
 220                 regs->ARM_r8);
 221         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 222                 regs->ARM_r7, regs->ARM_r6,
 223                 regs->ARM_r5, regs->ARM_r4);
 224         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 225                 regs->ARM_r3, regs->ARM_r2,
 226                 regs->ARM_r1, regs->ARM_r0);
 227
 228         flags = regs->ARM_cpsr;
 229         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 230         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 231         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 232         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 233         buf[4] = '\0';
 234
 235         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 236                 buf, interrupts_enabled(regs) ? "n" : "ff",
 237                 fast_interrupts_enabled(regs) ? "n" : "ff",
 238                 processor_modes[processor_mode(regs)],
 239                 isa_modes[isa_mode(regs)],
 240                 get_fs() == get_ds() ? "kernel" : "user");
 241 #ifdef CONFIG_CPU_CP15
 242         {
 243                 unsigned int ctrl;
 244
 245                 buf[0] = '\0';
 246 #ifdef CONFIG_CPU_CP15_MMU
 247                 {
 248                         unsigned int transbase, dac;
 249                         asm("mrc p15, 0, %0, c2, c0\n\t"
 250                             "mrc p15, 0, %1, c3, c0\n"
 251                             : "=r" (transbase), "=r" (dac));
 252                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 253                                 transbase, dac);
 254                 }
 255 #endif
 256                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 257
 258                 printk("Control: %08x%s\n", ctrl, buf);
 259         }
 260 #endif
 261 }
 262
 263 void show_regs(struct pt_regs * regs)
 264 {
 265         printk("\n");
 266         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 267         __show_regs(regs);
 268         __backtrace();
 269 }
 270
 271 /*
 272  * Free current thread data structures etc..
 273  */
 274 void exit_thread(void)
 275 {
 276 }
 277
 278 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 279
 280 EXPORT_SYMBOL_GPL(thread_notify_head);
 281
 282 void flush_thread(void)
 283 {
 284         struct thread_info *thread = current_thread_info();
 285         struct task_struct *tsk = current;
 286
 287         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 288         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 289         memset(&thread->fpstate, 0, sizeof(union fp_state));
 290
 291         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 292 }
 293
 294 void release_thread(struct task_struct *dead_task)
 295 {
 296         struct thread_info *thread = task_thread_info(dead_task);
 297
 298         thread_notify(THREAD_NOTIFY_RELEASE, thread);
 299 }
 300
 301 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 302
 303 int
 304 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 305             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 306 {
 307         struct thread_info *thread = task_thread_info(p);
 308         struct pt_regs *childregs = task_pt_regs(p);
 309
 310         *childregs = *regs;
 311         childregs->ARM_r0 = 0;
 312         childregs->ARM_sp = stack_start;
 313
 314         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 315         thread->cpu_context.sp = (unsigned long)childregs;
 316         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 317
 318         if (clone_flags & CLONE_SETTLS)
 319                 thread->tp_value = regs->ARM_r3;
 320
 321         return 0;
 322 }
 323
 324 /*
 325  * fill in the fpe structure for a core dump...
 326  */
 327 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 328 {
 329         struct thread_info *thread = current_thread_info();
 330         int used_math = thread->used_cp[1] | thread->used_cp[2];
 331
 332         if (used_math)
 333                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 334
 335         return used_math != 0;
 336 }
 337 EXPORT_SYMBOL(dump_fpu);
 338
 339 /*
 340  * Shuffle the argument into the correct register before calling the
 341  * thread function.  r1 is the thread argument, r2 is the pointer to
 342  * the thread function, and r3 points to the exit function.
 343  */
 344 extern void kernel_thread_helper(void);
 345 asm(    ".section .text\n"
 346 "       .align\n"
 347 "       .type   kernel_thread_helper, #function\n"
 348 "kernel_thread_helper:\n"
 349 "       mov     r0, r1\n"
 350 "       mov     lr, r3\n"
 351 "       mov     pc, r2\n"
 352 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 353 "       .previous");
 354
 355 /*
 356  * Create a kernel thread.
 357  */
 358 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 359 {
 360         struct pt_regs regs;
 361
 362         memset(&regs, 0, sizeof(regs));
 363
 364         regs.ARM_r1 = (unsigned long)arg;
 365         regs.ARM_r2 = (unsigned long)fn;
 366         regs.ARM_r3 = (unsigned long)do_exit;
 367         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 368         regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE;
 369
 370         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 371 }
 372 EXPORT_SYMBOL(kernel_thread);
 373
 374 unsigned long get_wchan(struct task_struct *p)
 375 {
 376         struct stackframe frame;
 377         int count = 0;
 378         if (!p || p == current || p->state == TASK_RUNNING)
 379                 return 0;
 380
 381         frame.fp = thread_saved_fp(p);
 382         frame.sp = thread_saved_sp(p);
 383         frame.lr = 0;                   /* recovered from the stack */
 384         frame.pc = thread_saved_pc(p);
 385         do {
 386                 int ret = unwind_frame(&frame);
 387                 if (ret < 0)
 388                         return 0;
 389                 if (!in_sched_functions(frame.pc))
 390                         return frame.pc;
 391         } while (count ++ < 16);
 392         return 0;
 393 }