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
   8 #include <stdarg.h>
   9
  10 #include <linux/config.h>
  11 #include <linux/sched.h>
  12 #include <linux/kernel.h>
  13 #include <linux/mm.h>
  14 #include <linux/stddef.h>
  15 #include <linux/unistd.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/malloc.h>
  18 #include <linux/user.h>
  19 #include <linux/delay.h>
  20 #include <linux/reboot.h>
  21 #include <linux/init.h>
  22
  23 #include <asm/system.h>
  24 #include <asm/io.h>
  25 #include <asm/leds.h>
  26 #include <asm/uaccess.h>
  27
  28 /*
  29  * Values for cpu_do_idle()
  30  */
  31 #define IDLE_WAIT_SLOW  0
  32 #define IDLE_WAIT_FAST  1
  33 #define IDLE_CLOCK_SLOW 2
  34 #define IDLE_CLOCK_FAST 3
  35
  36 extern const char *processor_modes[];
  37 extern void setup_mm_for_reboot(char mode);
  38
  39 asmlinkage void ret_from_sys_call(void) __asm__("ret_from_sys_call");
  40
  41 static volatile int hlt_counter;
  42
  43 #include <asm/arch/system.h>
  44
  45 void disable_hlt(void)
  46 {
  47         hlt_counter++;
  48 }
  49
  50 void enable_hlt(void)
  51 {
  52         hlt_counter--;
  53 }
  54
  55 static int __init nohlt_setup(char *__unused)
  56 {
  57         hlt_counter = 1;
  58         return 1;
  59 }
  60
  61 static int __init hlt_setup(char *__unused)
  62 {
  63         hlt_counter = 0;
  64         return 1;
  65 }
  66
  67 __setup("nohlt", nohlt_setup);
  68 __setup("hlt", hlt_setup);
  69
  70 /*
  71  * The following aren't currently used.
  72  */
  73 void (*pm_idle)(void);
  74 void (*pm_power_off)(void);
  75
  76 /*
  77  * The idle thread.  We try to conserve power, while trying to keep
  78  * overall latency low.  The architecture specific idle is passed
  79  * a value to indicate the level of "idleness" of the system.
  80  */
  81 void cpu_idle(void)
  82 {
  83         /* endless idle loop with no priority at all */
  84         init_idle();
  85         current->nice = 20;
  86         current->counter = -100;
  87
  88         while (1) {
  89                 void (*idle)(void) = pm_idle;
  90                 if (!idle)
  91                         idle = arch_idle;
  92                 while (!current->need_resched)
  93                         idle();
  94                 schedule();
  95 #ifndef CONFIG_NO_PGT_CACHE
  96                 check_pgt_cache();
  97 #endif
  98         }
  99 }
 100
 101 static char reboot_mode = 'h';
 102
 103 int __init reboot_setup(char *str)
 104 {
 105         reboot_mode = str[0];
 106         return 1;
 107 }
 108
 109 __setup("reboot=", reboot_setup);
 110
 111 void machine_halt(void)
 112 {
 113         leds_event(led_halted);
 114 }
 115
 116 void machine_power_off(void)
 117 {
 118         leds_event(led_halted);
 119         if (pm_power_off)
 120                 pm_power_off();
 121 }
 122
 123 void machine_restart(char * __unused)
 124 {
 125         /*
 126          * Clean and disable cache, and turn off interrupts
 127          */
 128         cpu_proc_fin();
 129
 130         /*
 131          * Tell the mm system that we are going to reboot -
 132          * we may need it to insert some 1:1 mappings so that
 133          * soft boot works.
 134          */
 135         setup_mm_for_reboot(reboot_mode);
 136
 137         /*
 138          * Now call the architecture specific reboot code.
 139          */
 140         arch_reset(reboot_mode);
 141
 142         /*
 143          * Whoops - the architecture was unable to reboot.
 144          * Tell the user!
 145          */
 146         mdelay(1000);
 147         printk("Reboot failed -- System halted\n");
 148         while (1);
 149 }
 150
 151 void show_regs(struct pt_regs * regs)
 152 {
 153         unsigned long flags;
 154
 155         flags = condition_codes(regs);
 156
 157         printk("pc : [<%08lx>]    lr : [<%08lx>]\n"
 158                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 159                 instruction_pointer(regs),
 160                 regs->ARM_lr, regs->ARM_sp,
 161                 regs->ARM_ip, regs->ARM_fp);
 162         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 163                 regs->ARM_r10, regs->ARM_r9,
 164                 regs->ARM_r8);
 165         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 166                 regs->ARM_r7, regs->ARM_r6,
 167                 regs->ARM_r5, regs->ARM_r4);
 168         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 169                 regs->ARM_r3, regs->ARM_r2,
 170                 regs->ARM_r1, regs->ARM_r0);
 171         printk("Flags: %c%c%c%c",
 172                 flags & CC_N_BIT ? 'N' : 'n',
 173                 flags & CC_Z_BIT ? 'Z' : 'z',
 174                 flags & CC_C_BIT ? 'C' : 'c',
 175                 flags & CC_V_BIT ? 'V' : 'v');
 176         printk("  IRQs %s  FIQs %s  Mode %s  Segment %s\n",
 177                 interrupts_enabled(regs) ? "on" : "off",
 178                 fast_interrupts_enabled(regs) ? "on" : "off",
 179                 processor_modes[processor_mode(regs)],
 180                 get_fs() == get_ds() ? "kernel" : "user");
 181 #if defined(CONFIG_CPU_32)
 182         {
 183                 int ctrl, transbase, dac;
 184                   __asm__ (
 185                 "       mrc p15, 0, %0, c1, c0\n"
 186                 "       mrc p15, 0, %1, c2, c0\n"
 187                 "       mrc p15, 0, %2, c3, c0\n"
 188                 : "=r" (ctrl), "=r" (transbase), "=r" (dac));
 189                 printk("Control: %04X  Table: %08X  DAC: %08X\n",
 190                         ctrl, transbase, dac);
 191         }
 192 #endif
 193 }
 194
 195 void show_fpregs(struct user_fp *regs)
 196 {
 197         int i;
 198
 199         for (i = 0; i < 8; i++) {
 200                 unsigned long *p;
 201                 char type;
 202
 203                 p = (unsigned long *)(regs->fpregs + i);
 204
 205                 switch (regs->ftype[i]) {
 206                         case 1: type = 'f'; break;
 207                         case 2: type = 'd'; break;
 208                         case 3: type = 'e'; break;
 209                         default: type = '?'; break;
 210                 }
 211                 if (regs->init_flag)
 212                         type = '?';
 213
 214                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 215                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 216         }
 217
 218
 219         printk("FPSR: %08lx FPCR: %08lx\n",
 220                 (unsigned long)regs->fpsr,
 221                 (unsigned long)regs->fpcr);
 222 }
 223
 224 /*
 225  * Task structure and kernel stack allocation.
 226  */
 227 static struct task_struct *task_struct_head;
 228 static unsigned int nr_task_struct;
 229
 230 #ifdef CONFIG_CPU_32
 231 #define EXTRA_TASK_STRUCT       4
 232 #else
 233 #define EXTRA_TASK_STRUCT       0
 234 #endif
 235
 236 struct task_struct *alloc_task_struct(void)
 237 {
 238         struct task_struct *tsk;
 239
 240         if (EXTRA_TASK_STRUCT)
 241                 tsk = task_struct_head;
 242         else
 243                 tsk = NULL;
 244
 245         if (tsk) {
 246                 task_struct_head = tsk->next_task;
 247                 nr_task_struct -= 1;
 248         } else
 249                 tsk = ll_alloc_task_struct();
 250
 251 #ifdef CONFIG_SYSRQ
 252         /*
 253          * The stack must be cleared if you want SYSRQ-T to
 254          * give sensible stack usage information
 255          */
 256         if (tsk) {
 257                 char *p = (char *)tsk;
 258                 memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
 259         }
 260 #endif
 261         return tsk;
 262 }
 263
 264 void __free_task_struct(struct task_struct *p)
 265 {
 266         if (EXTRA_TASK_STRUCT && nr_task_struct < EXTRA_TASK_STRUCT) {
 267                 p->next_task = task_struct_head;
 268                 task_struct_head = p;
 269                 nr_task_struct += 1;
 270         } else
 271                 ll_free_task_struct(p);
 272 }
 273
 274 /*
 275  * Free current thread data structures etc..
 276  */
 277 void exit_thread(void)
 278 {
 279 }
 280
 281 void flush_thread(void)
 282 {
 283         memset(&current->thread.debug, 0, sizeof(struct debug_info));
 284         memset(&current->thread.fpstate, 0, sizeof(union fp_state));
 285         current->used_math = 0;
 286         current->flags &= ~PF_USEDFPU;
 287 }
 288
 289 void release_thread(struct task_struct *dead_task)
 290 {
 291 }
 292
 293 int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
 294         struct task_struct * p, struct pt_regs * regs)
 295 {
 296         struct pt_regs * childregs;
 297         struct context_save_struct * save;
 298
 299         atomic_set(&p->thread.refcount, 1);
 300
 301         childregs = ((struct pt_regs *)((unsigned long)p + 8192)) - 1;
 302         *childregs = *regs;
 303         childregs->ARM_r0 = 0;
 304         childregs->ARM_sp = esp;
 305
 306         save = ((struct context_save_struct *)(childregs)) - 1;
 307         init_thread_css(save);
 308         p->thread.save = save;
 309
 310         return 0;
 311 }
 312
 313 /*
 314  * fill in the fpe structure for a core dump...
 315  */
 316 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 317 {
 318         if (current->used_math)
 319                 memcpy(fp, &current->thread.fpstate.soft, sizeof (*fp));
 320
 321         return current->used_math;
 322 }
 323
 324 /*
 325  * fill in the user structure for a core dump..
 326  */
 327 void dump_thread(struct pt_regs * regs, struct user * dump)
 328 {
 329         struct task_struct *tsk = current;
 330
 331         dump->magic = CMAGIC;
 332         dump->start_code = tsk->mm->start_code;
 333         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 334
 335         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 336         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 337         dump->u_ssize = 0;
 338
 339         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 340         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 341         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn;
 342         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
 343         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 344
 345         if (dump->start_stack < 0x04000000)
 346                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 347
 348         dump->regs = *regs;
 349         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 350 }
 351
 352 /*
 353  * This is the mechanism for creating a new kernel thread.
 354  *
 355  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 356  * who haven't done an "execve()") should use this: it will work within
 357  * a system call from a "real" process, but the process memory space will
 358  * not be free'd until both the parent and the child have exited.
 359  */
 360 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 361 {
 362         extern long sys_exit(int) __attribute__((noreturn));
 363         pid_t __ret;
 364
 365         __asm__ __volatile__(
 366         "mov    r0, %1          @ kernel_thread sys_clone
 367         mov     r1, #0
 368         "__syscall(clone)"
 369         teq     r0, #0          @ if we are the child
 370         moveq   fp, #0          @ ensure that fp is zero
 371         mov     %0, r0"
 372         : "=r" (__ret)
 373         : "Ir" (flags | CLONE_VM) : "r0", "r1");
 374         if (__ret == 0)
 375                 sys_exit((fn)(arg));
 376         return __ret;
 377 }
 378
 379 /*
 380  * These bracket the sleeping functions..
 381  */
 382 extern void scheduling_functions_start_here(void);
 383 extern void scheduling_functions_end_here(void);
 384 #define first_sched     ((unsigned long) scheduling_functions_start_here)
 385 #define last_sched      ((unsigned long) scheduling_functions_end_here)
 386
 387 unsigned long get_wchan(struct task_struct *p)
 388 {
 389         unsigned long fp, lr;
 390         unsigned long stack_page;
 391         int count = 0;
 392         if (!p || p == current || p->state == TASK_RUNNING)
 393                 return 0;
 394
 395         stack_page = 4096 + (unsigned long)p;
 396         fp = get_css_fp(&p->thread);
 397         do {
 398                 if (fp < stack_page || fp > 4092+stack_page)
 399                         return 0;
 400                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 401                 if (lr < first_sched || lr > last_sched)
 402                         return lr;
 403                 fp = *(unsigned long *) (fp - 12);
 404         } while (count ++ < 16);
 405         return 0;
 406 }