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