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  *  Origional 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 void enable_hlt(void)
  49 {
  50         hlt_counter--;
  51 }
  52
  53 static int __init nohlt_setup(char *__unused)
  54 {
  55         hlt_counter = 1;
  56         return 1;
  57 }
  58
  59 static int __init hlt_setup(char *__unused)
  60 {
  61         hlt_counter = 0;
  62         return 1;
  63 }
  64
  65 __setup("nohlt", nohlt_setup);
  66 __setup("hlt", hlt_setup);
  67
  68 /*
  69  * The following aren't currently used.
  70  */
  71 void (*pm_idle)(void);
  72 void (*pm_power_off)(void);
  73
  74 /*
  75  * This is our default idle handler.  We need to disable
  76  * interrupts here to ensure we don't miss a wakeup call.
  77  */
  78 void default_idle(void)
  79 {
  80         local_irq_disable();
  81         if (!need_resched() && !hlt_counter)
  82                 arch_idle();
  83         local_irq_enable();
  84 }
  85
  86 /*
  87  * The idle thread.  We try to conserve power, while trying to keep
  88  * overall latency low.  The architecture specific idle is passed
  89  * a value to indicate the level of "idleness" of the system.
  90  */
  91 void cpu_idle(void)
  92 {
  93         /* endless idle loop with no priority at all */
  94         while (1) {
  95                 void (*idle)(void) = pm_idle;
  96                 if (!idle)
  97                         idle = default_idle;
  98                 preempt_disable();
  99                 leds_event(led_idle_start);
 100                 while (!need_resched())
 101                         idle();
 102                 leds_event(led_idle_end);
 103                 preempt_enable();
 104                 schedule();
 105         }
 106 }
 107
 108 static char reboot_mode = 'h';
 109
 110 int __init reboot_setup(char *str)
 111 {
 112         reboot_mode = str[0];
 113         return 1;
 114 }
 115
 116 __setup("reboot=", reboot_setup);
 117
 118 void machine_halt(void)
 119 {
 120         leds_event(led_halted);
 121 }
 122
 123 void machine_power_off(void)
 124 {
 125         leds_event(led_halted);
 126         if (pm_power_off)
 127                 pm_power_off();
 128 }
 129
 130 void machine_restart(char * __unused)
 131 {
 132         /*
 133          * Clean and disable cache, and turn off interrupts
 134          */
 135         cpu_proc_fin();
 136
 137         /*
 138          * Tell the mm system that we are going to reboot -
 139          * we may need it to insert some 1:1 mappings so that
 140          * soft boot works.
 141          */
 142         setup_mm_for_reboot(reboot_mode);
 143
 144         /*
 145          * Now call the architecture specific reboot code.
 146          */
 147         arch_reset(reboot_mode);
 148
 149         /*
 150          * Whoops - the architecture was unable to reboot.
 151          * Tell the user!
 152          */
 153         mdelay(1000);
 154         printk("Reboot failed -- System halted\n");
 155         while (1);
 156 }
 157
 158 void show_regs(struct pt_regs * regs)
 159 {
 160         unsigned long flags;
 161
 162         flags = condition_codes(regs);
 163
 164         print_symbol("PC is at %s\n", instruction_pointer(regs));
 165         print_symbol("LR is at %s\n", regs->ARM_lr);
 166         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 167                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 168                 instruction_pointer(regs),
 169                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
 170                 regs->ARM_ip, regs->ARM_fp);
 171         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 172                 regs->ARM_r10, regs->ARM_r9,
 173                 regs->ARM_r8);
 174         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 175                 regs->ARM_r7, regs->ARM_r6,
 176                 regs->ARM_r5, regs->ARM_r4);
 177         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 178                 regs->ARM_r3, regs->ARM_r2,
 179                 regs->ARM_r1, regs->ARM_r0);
 180         printk("Flags: %c%c%c%c",
 181                 flags & PSR_N_BIT ? 'N' : 'n',
 182                 flags & PSR_Z_BIT ? 'Z' : 'z',
 183                 flags & PSR_C_BIT ? 'C' : 'c',
 184                 flags & PSR_V_BIT ? 'V' : 'v');
 185         printk("  IRQs o%s  FIQs o%s  Mode %s%s  Segment %s\n",
 186                 interrupts_enabled(regs) ? "n" : "ff",
 187                 fast_interrupts_enabled(regs) ? "n" : "ff",
 188                 processor_modes[processor_mode(regs)],
 189                 thumb_mode(regs) ? " (T)" : "",
 190                 get_fs() == get_ds() ? "kernel" : "user");
 191 #if defined(CONFIG_CPU_32)
 192         {
 193                 unsigned int ctrl, transbase, dac;
 194                   __asm__ (
 195                 "       mrc p15, 0, %0, c1, c0\n"
 196                 "       mrc p15, 0, %1, c2, c0\n"
 197                 "       mrc p15, 0, %2, c3, c0\n"
 198                 : "=r" (ctrl), "=r" (transbase), "=r" (dac));
 199                 printk("Control: %04X  Table: %08X  DAC: %08X\n",
 200                         ctrl, transbase, dac);
 201         }
 202 #endif
 203 }
 204
 205 void show_fpregs(struct user_fp *regs)
 206 {
 207         int i;
 208
 209         for (i = 0; i < 8; i++) {
 210                 unsigned long *p;
 211                 char type;
 212
 213                 p = (unsigned long *)(regs->fpregs + i);
 214
 215                 switch (regs->ftype[i]) {
 216                         case 1: type = 'f'; break;
 217                         case 2: type = 'd'; break;
 218                         case 3: type = 'e'; break;
 219                         default: type = '?'; break;
 220                 }
 221                 if (regs->init_flag)
 222                         type = '?';
 223
 224                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 225                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 226         }
 227
 228
 229         printk("FPSR: %08lx FPCR: %08lx\n",
 230                 (unsigned long)regs->fpsr,
 231                 (unsigned long)regs->fpcr);
 232 }
 233
 234 /*
 235  * Task structure and kernel stack allocation.
 236  */
 237 static unsigned long *thread_info_head;
 238 static unsigned int nr_thread_info;
 239
 240 #ifdef CONFIG_CPU_32
 241 #define EXTRA_TASK_STRUCT       4
 242 #define ll_alloc_task_struct() ((struct thread_info *) __get_free_pages(GFP_KERNEL,1))
 243 #define ll_free_task_struct(p) free_pages((unsigned long)(p),1)
 244 #else
 245 extern unsigned long get_page_8k(int priority);
 246 extern void free_page_8k(unsigned long page);
 247
 248 #define EXTRA_TASK_STRUCT       0
 249 #define ll_alloc_task_struct()  ((struct task_struct *)get_page_8k(GFP_KERNEL))
 250 #define ll_free_task_struct(p)  free_page_8k((unsigned long)(p))
 251 #endif
 252
 253 struct thread_info *alloc_thread_info(void)
 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_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
 308 void flush_thread(void)
 309 {
 310         struct thread_info *thread = current_thread_info();
 311         struct task_struct *tsk = current;
 312
 313         tsk->used_math = 0;
 314
 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 esp,
 327             unsigned long unused, 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 = esp;
 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 = current->used_math;
 351
 352         if (used_math)
 353                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 354
 355         return used_math;
 356 }
 357
 358 /*
 359  * fill in the user structure for a core dump..
 360  */
 361 void dump_thread(struct pt_regs * regs, struct user * dump)
 362 {
 363         struct task_struct *tsk = current;
 364
 365         dump->magic = CMAGIC;
 366         dump->start_code = tsk->mm->start_code;
 367         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 368
 369         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 370         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 371         dump->u_ssize = 0;
 372
 373         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 374         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 375         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
 376         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
 377         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 378
 379         if (dump->start_stack < 0x04000000)
 380                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 381
 382         dump->regs = *regs;
 383         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 384 }
 385
 386 /*
 387  * This is the mechanism for creating a new kernel thread.
 388  *
 389  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 390  * who haven't done an "execve()") should use this: it will work within
 391  * a system call from a "real" process, but the process memory space will
 392  * not be free'd until both the parent and the child have exited.
 393  */
 394 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 395 {
 396         register unsigned int r0 asm("r0") = flags | CLONE_VM | CLONE_UNTRACED;
 397         register unsigned int r1 asm("r1") = 0;
 398         register pid_t __ret asm("r0");
 399
 400         __asm__ __volatile__(
 401         __syscall(clone)"       @ kernel_thread sys_clone       \n\
 402         movs    %0, r0          @ if we are the child           \n\
 403         bne     1f                                              \n\
 404         mov     fp, #0          @ ensure that fp is zero        \n\
 405         mov     r0, %4                                          \n\
 406         mov     lr, pc                                          \n\
 407         mov     pc, %3                                          \n\
 408         b       sys_exit                                        \n\
 409 1:      "
 410         : "=r" (__ret)
 411         : "0" (r0), "r" (r1), "r" (fn), "r" (arg)
 412         : "lr");
 413         return __ret;
 414 }
 415
 416 /*
 417  * These bracket the sleeping functions..
 418  */
 419 extern void scheduling_functions_start_here(void);
 420 extern void scheduling_functions_end_here(void);
 421 #define first_sched     ((unsigned long) scheduling_functions_start_here)
 422 #define last_sched      ((unsigned long) scheduling_functions_end_here)
 423
 424 unsigned long get_wchan(struct task_struct *p)
 425 {
 426         unsigned long fp, lr;
 427         unsigned long stack_page;
 428         int count = 0;
 429         if (!p || p == current || p->state == TASK_RUNNING)
 430                 return 0;
 431
 432         stack_page = 4096 + (unsigned long)p;
 433         fp = thread_saved_fp(p);
 434         do {
 435                 if (fp < stack_page || fp > 4092+stack_page)
 436                         return 0;
 437                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 438                 if (lr < first_sched || lr > last_sched)
 439                         return lr;
 440                 fp = *(unsigned long *) (fp - 12);
 441         } while (count ++ < 16);
 442         return 0;
 443 }