arch/arm26/kernel/process.c

   1 /*
   2  *  linux/arch/arm26/kernel/process.c
   3  *
   4  *  Copyright (C) 2003 Ian Molton - adapted for ARM26
   5  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
   6  *  Origional Copyright (C) 1995  Linus Torvalds
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #include <stdarg.h>
  13
  14 #include <linux/config.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.h>
  19 #include <linux/stddef.h>
  20 #include <linux/unistd.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/slab.h>
  23 #include <linux/user.h>
  24 #include <linux/a.out.h>
  25 #include <linux/delay.h>
  26 #include <linux/reboot.h>
  27 #include <linux/interrupt.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 void disable_hlt(void)
  42 {
  43         hlt_counter++;
  44 }
  45
  46 EXPORT_SYMBOL(disable_hlt);
  47
  48 void enable_hlt(void)
  49 {
  50         hlt_counter--;
  51 }
  52
  53 EXPORT_SYMBOL(enable_hlt);
  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  * This is our default idle handler.  We need to disable
  72  * interrupts here to ensure we don't miss a wakeup call.
  73  */
  74 void cpu_idle(void)
  75 {
  76         /* endless idle loop with no priority at all */
  77         preempt_disable();
  78         while (1) {
  79                 while (!need_resched()) {
  80                         local_irq_disable();
  81                         if (!need_resched() && !hlt_counter)
  82                                 local_irq_enable();
  83                 }
  84         }
  85         schedule();
  86 }
  87
  88 static char reboot_mode = 'h';
  89
  90 int __init reboot_setup(char *str)
  91 {
  92         reboot_mode = str[0];
  93         return 1;
  94 }
  95
  96 __setup("reboot=", reboot_setup);
  97
  98 /* ARM26 cant do these but we still need to define them. */
  99 void machine_halt(void)
 100 {
 101 }
 102 void machine_power_off(void)
 103 {
 104 }
 105
 106 void machine_restart(char * __unused)
 107 {
 108         /*
 109          * Clean and disable cache, and turn off interrupts
 110          */
 111         cpu_proc_fin();
 112
 113         /*
 114          * Tell the mm system that we are going to reboot -
 115          * we may need it to insert some 1:1 mappings so that
 116          * soft boot works.
 117          */
 118         setup_mm_for_reboot(reboot_mode);
 119
 120         /*
 121          * copy branch instruction to reset location and call it
 122          */
 123
 124         *(unsigned long *)0 = *(unsigned long *)0x03800000;
 125         ((void(*)(void))0)();
 126
 127         /*
 128          * Whoops - the architecture was unable to reboot.
 129          * Tell the user! Should never happen...
 130          */
 131         mdelay(1000);
 132         printk("Reboot failed -- System halted\n");
 133         while (1);
 134 }
 135
 136 void show_regs(struct pt_regs * regs)
 137 {
 138         unsigned long flags;
 139
 140         flags = condition_codes(regs);
 141
 142         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 143                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 144                 instruction_pointer(regs),
 145                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
 146                 regs->ARM_ip, regs->ARM_fp);
 147         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 148                 regs->ARM_r10, regs->ARM_r9,
 149                 regs->ARM_r8);
 150         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 151                 regs->ARM_r7, regs->ARM_r6,
 152                 regs->ARM_r5, regs->ARM_r4);
 153         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 154                 regs->ARM_r3, regs->ARM_r2,
 155                 regs->ARM_r1, regs->ARM_r0);
 156         printk("Flags: %c%c%c%c",
 157                 flags & PSR_N_BIT ? 'N' : 'n',
 158                 flags & PSR_Z_BIT ? 'Z' : 'z',
 159                 flags & PSR_C_BIT ? 'C' : 'c',
 160                 flags & PSR_V_BIT ? 'V' : 'v');
 161         printk("  IRQs o%s  FIQs o%s  Mode %s  Segment %s\n",
 162                 interrupts_enabled(regs) ? "n" : "ff",
 163                 fast_interrupts_enabled(regs) ? "n" : "ff",
 164                 processor_modes[processor_mode(regs)],
 165                 get_fs() == get_ds() ? "kernel" : "user");
 166 }
 167
 168 void show_fpregs(struct user_fp *regs)
 169 {
 170         int i;
 171
 172         for (i = 0; i < 8; i++) {
 173                 unsigned long *p;
 174                 char type;
 175
 176                 p = (unsigned long *)(regs->fpregs + i);
 177
 178                 switch (regs->ftype[i]) {
 179                         case 1: type = 'f'; break;
 180                         case 2: type = 'd'; break;
 181                         case 3: type = 'e'; break;
 182                         default: type = '?'; break;
 183                 }
 184                 if (regs->init_flag)
 185                         type = '?';
 186
 187                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 188                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 189         }
 190
 191
 192         printk("FPSR: %08lx FPCR: %08lx\n",
 193                 (unsigned long)regs->fpsr,
 194                 (unsigned long)regs->fpcr);
 195 }
 196
 197 /*
 198  * Task structure and kernel stack allocation.
 199  */
 200 static unsigned long *thread_info_head;
 201 static unsigned int nr_thread_info;
 202
 203 extern unsigned long get_page_8k(int priority);
 204 extern void free_page_8k(unsigned long page);
 205
 206 // FIXME - is this valid?
 207 #define EXTRA_TASK_STRUCT       0
 208 #define ll_alloc_task_struct()  ((struct thread_info *)get_page_8k(GFP_KERNEL))
 209 #define ll_free_task_struct(p)  free_page_8k((unsigned long)(p))
 210
 211 //FIXME - do we use *task param below looks like we dont, which is ok?
 212 //FIXME - if EXTRA_TASK_STRUCT is zero we can optimise the below away permanently. *IF* its supposed to be zero.
 213 struct thread_info *alloc_thread_info(struct task_struct *task)
 214 {
 215         struct thread_info *thread = NULL;
 216
 217         if (EXTRA_TASK_STRUCT) {
 218                 unsigned long *p = thread_info_head;
 219
 220                 if (p) {
 221                         thread_info_head = (unsigned long *)p[0];
 222                         nr_thread_info -= 1;
 223                 }
 224                 thread = (struct thread_info *)p;
 225         }
 226
 227         if (!thread)
 228                 thread = ll_alloc_task_struct();
 229
 230 #ifdef CONFIG_MAGIC_SYSRQ
 231         /*
 232          * The stack must be cleared if you want SYSRQ-T to
 233          * give sensible stack usage information
 234          */
 235         if (thread) {
 236                 char *p = (char *)thread;
 237                 memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
 238         }
 239 #endif
 240         return thread;
 241 }
 242
 243 void free_thread_info(struct thread_info *thread)
 244 {
 245         if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
 246                 unsigned long *p = (unsigned long *)thread;
 247                 p[0] = (unsigned long)thread_info_head;
 248                 thread_info_head = p;
 249                 nr_thread_info += 1;
 250         } else
 251                 ll_free_task_struct(thread);
 252 }
 253
 254 /*
 255  * Free current thread data structures etc..
 256  */
 257 void exit_thread(void)
 258 {
 259 }
 260
 261 void flush_thread(void)
 262 {
 263         struct thread_info *thread = current_thread_info();
 264         struct task_struct *tsk = current;
 265
 266         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 267         memset(&thread->fpstate, 0, sizeof(union fp_state));
 268
 269         clear_used_math();
 270 }
 271
 272 void release_thread(struct task_struct *dead_task)
 273 {
 274 }
 275
 276 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 277
 278 int
 279 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 280             unsigned long unused, struct task_struct *p, struct pt_regs *regs)
 281 {
 282         struct thread_info *thread = p->thread_info;
 283         struct pt_regs *childregs;
 284
 285         childregs = __get_user_regs(thread);
 286         *childregs = *regs;
 287         childregs->ARM_r0 = 0;
 288         childregs->ARM_sp = stack_start;
 289
 290         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 291         thread->cpu_context.sp = (unsigned long)childregs;
 292         thread->cpu_context.pc = (unsigned long)ret_from_fork | MODE_SVC26 | PSR_I_BIT;
 293
 294         return 0;
 295 }
 296
 297 /*
 298  * fill in the fpe structure for a core dump...
 299  */
 300 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 301 {
 302         struct thread_info *thread = current_thread_info();
 303         int used_math = !!used_math();
 304
 305         if (used_math)
 306                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 307
 308         return used_math;
 309 }
 310
 311 /*
 312  * fill in the user structure for a core dump..
 313  */
 314 void dump_thread(struct pt_regs * regs, struct user * dump)
 315 {
 316         struct task_struct *tsk = current;
 317
 318         dump->magic = CMAGIC;
 319         dump->start_code = tsk->mm->start_code;
 320         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 321
 322         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 323         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 324         dump->u_ssize = 0;
 325
 326         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 327         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 328         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn;
 329         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
 330         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 331
 332         if (dump->start_stack < 0x04000000)
 333                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 334
 335         dump->regs = *regs;
 336         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 337 }
 338
 339 /*
 340  * Shuffle the argument into the correct register before calling the
 341  * thread function.  r1 is the thread argument, r2 is the pointer to
 342  * the thread function, and r3 points to the exit function.
 343  * FIXME - make sure this is right - the older code used to zero fp
 344  * and cause the parent to call sys_exit (do_exit in this version)
 345  */
 346 extern void kernel_thread_helper(void);
 347
 348 asm(    ".section .text\n"
 349 "       .align\n"
 350 "       .type   kernel_thread_helper, #function\n"
 351 "kernel_thread_helper:\n"
 352 "       mov     r0, r1\n"
 353 "       mov     lr, r3\n"
 354 "       mov     pc, r2\n"
 355 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 356 "       .previous");
 357
 358 /*
 359  * Create a kernel thread.
 360  */
 361 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 362 {
 363         struct pt_regs regs;
 364
 365         memset(&regs, 0, sizeof(regs));
 366
 367         regs.ARM_r1 = (unsigned long)arg;
 368         regs.ARM_r2 = (unsigned long)fn;
 369         regs.ARM_r3 = (unsigned long)do_exit;
 370         regs.ARM_pc = (unsigned long)kernel_thread_helper | MODE_SVC26;
 371
 372         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 373 }
 374 EXPORT_SYMBOL(kernel_thread);
 375
 376
 377 unsigned long get_wchan(struct task_struct *p)
 378 {
 379         unsigned long fp, lr;
 380         unsigned long stack_page;
 381         int count = 0;
 382         if (!p || p == current || p->state == TASK_RUNNING)
 383                 return 0;
 384
 385         stack_page = 4096 + (unsigned long)p;
 386         fp = thread_saved_fp(p);
 387         do {
 388                 if (fp < stack_page || fp > 4092+stack_page)
 389                         return 0;
 390                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 391                 if (!in_sched_functions(lr))
 392                         return lr;
 393                 fp = *(unsigned long *) (fp - 12);
 394         } while (count ++ < 16);
 395         return 0;
 396 }