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