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/config.h>
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/stddef.h>
  19 #include <linux/unistd.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/slab.h>
  22 #include <linux/user.h>
  23 #include <linux/a.out.h>
  24 #include <linux/delay.h>
  25 #include <linux/reboot.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/kallsyms.h>
  28 #include <linux/init.h>
  29
  30 #include <asm/system.h>
  31 #include <asm/io.h>
  32 #include <asm/leds.h>
  33 #include <asm/processor.h>
  34 #include <asm/uaccess.h>
  35
  36 extern const char *processor_modes[];
  37 extern void setup_mm_for_reboot(char mode);
  38
  39 static volatile int hlt_counter;
  40
  41 #include <asm/arch/system.h>
  42
  43 void disable_hlt(void)
  44 {
  45         hlt_counter++;
  46 }
  47
  48 EXPORT_SYMBOL(disable_hlt);
  49
  50 void enable_hlt(void)
  51 {
  52         hlt_counter--;
  53 }
  54
  55 EXPORT_SYMBOL(enable_hlt);
  56
  57 static int __init nohlt_setup(char *__unused)
  58 {
  59         hlt_counter = 1;
  60         return 1;
  61 }
  62
  63 static int __init hlt_setup(char *__unused)
  64 {
  65         hlt_counter = 0;
  66         return 1;
  67 }
  68
  69 __setup("nohlt", nohlt_setup);
  70 __setup("hlt", hlt_setup);
  71
  72 /*
  73  * The following aren't currently used.
  74  */
  75 void (*pm_idle)(void);
  76 EXPORT_SYMBOL(pm_idle);
  77
  78 void (*pm_power_off)(void);
  79 EXPORT_SYMBOL(pm_power_off);
  80
  81 /*
  82  * This is our default idle handler.  We need to disable
  83  * interrupts here to ensure we don't miss a wakeup call.
  84  */
  85 void default_idle(void)
  86 {
  87         local_irq_disable();
  88         if (!need_resched() && !hlt_counter)
  89                 arch_idle();
  90         local_irq_enable();
  91 }
  92
  93 /*
  94  * The idle thread.  We try to conserve power, while trying to keep
  95  * overall latency low.  The architecture specific idle is passed
  96  * a value to indicate the level of "idleness" of the system.
  97  */
  98 void cpu_idle(void)
  99 {
 100         local_fiq_enable();
 101
 102         /* endless idle loop with no priority at all */
 103         while (1) {
 104                 void (*idle)(void) = pm_idle;
 105                 if (!idle)
 106                         idle = default_idle;
 107                 preempt_disable();
 108                 leds_event(led_idle_start);
 109                 while (!need_resched())
 110                         idle();
 111                 leds_event(led_idle_end);
 112                 preempt_enable();
 113                 schedule();
 114         }
 115 }
 116
 117 static char reboot_mode = 'h';
 118
 119 int __init reboot_setup(char *str)
 120 {
 121         reboot_mode = str[0];
 122         return 1;
 123 }
 124
 125 __setup("reboot=", reboot_setup);
 126
 127 void machine_halt(void)
 128 {
 129 }
 130
 131 EXPORT_SYMBOL(machine_halt);
 132
 133 void machine_power_off(void)
 134 {
 135         if (pm_power_off)
 136                 pm_power_off();
 137 }
 138
 139 EXPORT_SYMBOL(machine_power_off);
 140
 141 void machine_restart(char * __unused)
 142 {
 143         /*
 144          * Clean and disable cache, and turn off interrupts
 145          */
 146         cpu_proc_fin();
 147
 148         /*
 149          * Tell the mm system that we are going to reboot -
 150          * we may need it to insert some 1:1 mappings so that
 151          * soft boot works.
 152          */
 153         setup_mm_for_reboot(reboot_mode);
 154
 155         /*
 156          * Now call the architecture specific reboot code.
 157          */
 158         arch_reset(reboot_mode);
 159
 160         /*
 161          * Whoops - the architecture was unable to reboot.
 162          * Tell the user!
 163          */
 164         mdelay(1000);
 165         printk("Reboot failed -- System halted\n");
 166         while (1);
 167 }
 168
 169 EXPORT_SYMBOL(machine_restart);
 170
 171 void show_regs(struct pt_regs * regs)
 172 {
 173         unsigned long flags;
 174
 175         flags = condition_codes(regs);
 176
 177         print_symbol("PC is at %s\n", instruction_pointer(regs));
 178         print_symbol("LR is at %s\n", regs->ARM_lr);
 179         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 180                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 181                 instruction_pointer(regs),
 182                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
 183                 regs->ARM_ip, regs->ARM_fp);
 184         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 185                 regs->ARM_r10, regs->ARM_r9,
 186                 regs->ARM_r8);
 187         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 188                 regs->ARM_r7, regs->ARM_r6,
 189                 regs->ARM_r5, regs->ARM_r4);
 190         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 191                 regs->ARM_r3, regs->ARM_r2,
 192                 regs->ARM_r1, regs->ARM_r0);
 193         printk("Flags: %c%c%c%c",
 194                 flags & PSR_N_BIT ? 'N' : 'n',
 195                 flags & PSR_Z_BIT ? 'Z' : 'z',
 196                 flags & PSR_C_BIT ? 'C' : 'c',
 197                 flags & PSR_V_BIT ? 'V' : 'v');
 198         printk("  IRQs o%s  FIQs o%s  Mode %s%s  Segment %s\n",
 199                 interrupts_enabled(regs) ? "n" : "ff",
 200                 fast_interrupts_enabled(regs) ? "n" : "ff",
 201                 processor_modes[processor_mode(regs)],
 202                 thumb_mode(regs) ? " (T)" : "",
 203                 get_fs() == get_ds() ? "kernel" : "user");
 204         {
 205                 unsigned int ctrl, transbase, dac;
 206                   __asm__ (
 207                 "       mrc p15, 0, %0, c1, c0\n"
 208                 "       mrc p15, 0, %1, c2, c0\n"
 209                 "       mrc p15, 0, %2, c3, c0\n"
 210                 : "=r" (ctrl), "=r" (transbase), "=r" (dac));
 211                 printk("Control: %04X  Table: %08X  DAC: %08X\n",
 212                         ctrl, transbase, dac);
 213         }
 214 }
 215
 216 void show_fpregs(struct user_fp *regs)
 217 {
 218         int i;
 219
 220         for (i = 0; i < 8; i++) {
 221                 unsigned long *p;
 222                 char type;
 223
 224                 p = (unsigned long *)(regs->fpregs + i);
 225
 226                 switch (regs->ftype[i]) {
 227                         case 1: type = 'f'; break;
 228                         case 2: type = 'd'; break;
 229                         case 3: type = 'e'; break;
 230                         default: type = '?'; break;
 231                 }
 232                 if (regs->init_flag)
 233                         type = '?';
 234
 235                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 236                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 237         }
 238
 239
 240         printk("FPSR: %08lx FPCR: %08lx\n",
 241                 (unsigned long)regs->fpsr,
 242                 (unsigned long)regs->fpcr);
 243 }
 244
 245 /*
 246  * Task structure and kernel stack allocation.
 247  */
 248 static unsigned long *thread_info_head;
 249 static unsigned int nr_thread_info;
 250
 251 #define EXTRA_TASK_STRUCT       4
 252 #define ll_alloc_task_struct() ((struct thread_info *) __get_free_pages(GFP_KERNEL,1))
 253 #define ll_free_task_struct(p) free_pages((unsigned long)(p),1)
 254
 255 struct thread_info *alloc_thread_info(struct task_struct *task)
 256 {
 257         struct thread_info *thread = NULL;
 258
 259         if (EXTRA_TASK_STRUCT) {
 260                 unsigned long *p = thread_info_head;
 261
 262                 if (p) {
 263                         thread_info_head = (unsigned long *)p[0];
 264                         nr_thread_info -= 1;
 265                 }
 266                 thread = (struct thread_info *)p;
 267         }
 268
 269         if (!thread)
 270                 thread = ll_alloc_task_struct();
 271
 272 #ifdef CONFIG_MAGIC_SYSRQ
 273         /*
 274          * The stack must be cleared if you want SYSRQ-T to
 275          * give sensible stack usage information
 276          */
 277         if (thread) {
 278                 char *p = (char *)thread;
 279                 memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
 280         }
 281 #endif
 282         return thread;
 283 }
 284
 285 void free_thread_info(struct thread_info *thread)
 286 {
 287         if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
 288                 unsigned long *p = (unsigned long *)thread;
 289                 p[0] = (unsigned long)thread_info_head;
 290                 thread_info_head = p;
 291                 nr_thread_info += 1;
 292         } else
 293                 ll_free_task_struct(thread);
 294 }
 295
 296 /*
 297  * Free current thread data structures etc..
 298  */
 299 void exit_thread(void)
 300 {
 301 }
 302
 303 static void default_fp_init(union fp_state *fp)
 304 {
 305         memset(fp, 0, sizeof(union fp_state));
 306 }
 307
 308 void (*fp_init)(union fp_state *) = default_fp_init;
 309 EXPORT_SYMBOL(fp_init);
 310
 311 void flush_thread(void)
 312 {
 313         struct thread_info *thread = current_thread_info();
 314         struct task_struct *tsk = current;
 315
 316         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 317         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 318 #if defined(CONFIG_IWMMXT)
 319         iwmmxt_task_release(thread);
 320 #endif
 321         fp_init(&thread->fpstate);
 322 #if defined(CONFIG_VFP)
 323         vfp_flush_thread(&thread->vfpstate);
 324 #endif
 325 }
 326
 327 void release_thread(struct task_struct *dead_task)
 328 {
 329 #if defined(CONFIG_VFP)
 330         vfp_release_thread(&dead_task->thread_info->vfpstate);
 331 #endif
 332 #if defined(CONFIG_IWMMXT)
 333         iwmmxt_task_release(dead_task->thread_info);
 334 #endif
 335 }
 336
 337 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 338
 339 int
 340 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 341             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 342 {
 343         struct thread_info *thread = p->thread_info;
 344         struct pt_regs *childregs;
 345
 346         childregs = ((struct pt_regs *)((unsigned long)thread + THREAD_SIZE - 8)) - 1;
 347         *childregs = *regs;
 348         childregs->ARM_r0 = 0;
 349         childregs->ARM_sp = stack_start;
 350
 351         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 352         thread->cpu_context.sp = (unsigned long)childregs;
 353         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 354
 355         if (clone_flags & CLONE_SETTLS)
 356                 thread->tp_value = regs->ARM_r3;
 357
 358         return 0;
 359 }
 360
 361 /*
 362  * fill in the fpe structure for a core dump...
 363  */
 364 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 365 {
 366         struct thread_info *thread = current_thread_info();
 367         int used_math = thread->used_cp[1] | thread->used_cp[2];
 368
 369         if (used_math)
 370                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 371
 372         return used_math != 0;
 373 }
 374 EXPORT_SYMBOL(dump_fpu);
 375
 376 /*
 377  * fill in the user structure for a core dump..
 378  */
 379 void dump_thread(struct pt_regs * regs, struct user * dump)
 380 {
 381         struct task_struct *tsk = current;
 382
 383         dump->magic = CMAGIC;
 384         dump->start_code = tsk->mm->start_code;
 385         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 386
 387         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 388         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 389         dump->u_ssize = 0;
 390
 391         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 392         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 393         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
 394         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
 395         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 396
 397         if (dump->start_stack < 0x04000000)
 398                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 399
 400         dump->regs = *regs;
 401         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 402 }
 403 EXPORT_SYMBOL(dump_thread);
 404
 405 /*
 406  * Shuffle the argument into the correct register before calling the
 407  * thread function.  r1 is the thread argument, r2 is the pointer to
 408  * the thread function, and r3 points to the exit function.
 409  */
 410 extern void kernel_thread_helper(void);
 411 asm(    ".section .text\n"
 412 "       .align\n"
 413 "       .type   kernel_thread_helper, #function\n"
 414 "kernel_thread_helper:\n"
 415 "       mov     r0, r1\n"
 416 "       mov     lr, r3\n"
 417 "       mov     pc, r2\n"
 418 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 419 "       .previous");
 420
 421 /*
 422  * Create a kernel thread.
 423  */
 424 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 425 {
 426         struct pt_regs regs;
 427
 428         memset(&regs, 0, sizeof(regs));
 429
 430         regs.ARM_r1 = (unsigned long)arg;
 431         regs.ARM_r2 = (unsigned long)fn;
 432         regs.ARM_r3 = (unsigned long)do_exit;
 433         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 434         regs.ARM_cpsr = SVC_MODE;
 435
 436         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 437 }
 438 EXPORT_SYMBOL(kernel_thread);
 439
 440 unsigned long get_wchan(struct task_struct *p)
 441 {
 442         unsigned long fp, lr;
 443         unsigned long stack_page;
 444         int count = 0;
 445         if (!p || p == current || p->state == TASK_RUNNING)
 446                 return 0;
 447
 448         stack_page = 4096 + (unsigned long)p->thread_info;
 449         fp = thread_saved_fp(p);
 450         do {
 451                 if (fp < stack_page || fp > 4092+stack_page)
 452                         return 0;
 453                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 454                 if (!in_sched_functions(lr))
 455                         return lr;
 456                 fp = *(unsigned long *) (fp - 12);
 457         } while (count ++ < 16);
 458         return 0;
 459 }
 460 EXPORT_SYMBOL(get_wchan);