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/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/init.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/io.h>
  31 #include <asm/leds.h>
  32 #include <asm/processor.h>
  33 #include <asm/uaccess.h>
  34
  35 extern const char *processor_modes[];
  36 extern void setup_mm_for_reboot(char mode);
  37
  38 static volatile int hlt_counter;
  39
  40 void disable_hlt(void)
  41 {
  42         hlt_counter++;
  43 }
  44
  45 EXPORT_SYMBOL(disable_hlt);
  46
  47 void enable_hlt(void)
  48 {
  49         hlt_counter--;
  50 }
  51
  52 EXPORT_SYMBOL(enable_hlt);
  53
  54 static int __init nohlt_setup(char *__unused)
  55 {
  56         hlt_counter = 1;
  57         return 1;
  58 }
  59
  60 static int __init hlt_setup(char *__unused)
  61 {
  62         hlt_counter = 0;
  63         return 1;
  64 }
  65
  66 __setup("nohlt", nohlt_setup);
  67 __setup("hlt", hlt_setup);
  68
  69 /*
  70  * This is our default idle handler.  We need to disable
  71  * interrupts here to ensure we don't miss a wakeup call.
  72  */
  73 void cpu_idle(void)
  74 {
  75         /* endless idle loop with no priority at all */
  76         while (1) {
  77                 while (!need_resched())
  78                         cpu_relax();
  79                 preempt_enable_no_resched();
  80                 schedule();
  81                 preempt_disable();
  82         }
  83 }
  84
  85 static char reboot_mode = 'h';
  86
  87 int __init reboot_setup(char *str)
  88 {
  89         reboot_mode = str[0];
  90         return 1;
  91 }
  92
  93 __setup("reboot=", reboot_setup);
  94
  95 /* ARM26 cant do these but we still need to define them. */
  96 void machine_halt(void)
  97 {
  98 }
  99 void machine_power_off(void)
 100 {
 101 }
 102
 103 void machine_restart(char * __unused)
 104 {
 105         /*
 106          * Clean and disable cache, and turn off interrupts
 107          */
 108         cpu_proc_fin();
 109
 110         /*
 111          * Tell the mm system that we are going to reboot -
 112          * we may need it to insert some 1:1 mappings so that
 113          * soft boot works.
 114          */
 115         setup_mm_for_reboot(reboot_mode);
 116
 117         /*
 118          * copy branch instruction to reset location and call it
 119          */
 120
 121         *(unsigned long *)0 = *(unsigned long *)0x03800000;
 122         ((void(*)(void))0)();
 123
 124         /*
 125          * Whoops - the architecture was unable to reboot.
 126          * Tell the user! Should never happen...
 127          */
 128         mdelay(1000);
 129         printk("Reboot failed -- System halted\n");
 130         while (1);
 131 }
 132
 133 void show_regs(struct pt_regs * regs)
 134 {
 135         unsigned long flags;
 136
 137         flags = condition_codes(regs);
 138
 139         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 140                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 141                 instruction_pointer(regs),
 142                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
 143                 regs->ARM_ip, regs->ARM_fp);
 144         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 145                 regs->ARM_r10, regs->ARM_r9,
 146                 regs->ARM_r8);
 147         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 148                 regs->ARM_r7, regs->ARM_r6,
 149                 regs->ARM_r5, regs->ARM_r4);
 150         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 151                 regs->ARM_r3, regs->ARM_r2,
 152                 regs->ARM_r1, regs->ARM_r0);
 153         printk("Flags: %c%c%c%c",
 154                 flags & PSR_N_BIT ? 'N' : 'n',
 155                 flags & PSR_Z_BIT ? 'Z' : 'z',
 156                 flags & PSR_C_BIT ? 'C' : 'c',
 157                 flags & PSR_V_BIT ? 'V' : 'v');
 158         printk("  IRQs o%s  FIQs o%s  Mode %s  Segment %s\n",
 159                 interrupts_enabled(regs) ? "n" : "ff",
 160                 fast_interrupts_enabled(regs) ? "n" : "ff",
 161                 processor_modes[processor_mode(regs)],
 162                 get_fs() == get_ds() ? "kernel" : "user");
 163 }
 164
 165 void show_fpregs(struct user_fp *regs)
 166 {
 167         int i;
 168
 169         for (i = 0; i < 8; i++) {
 170                 unsigned long *p;
 171                 char type;
 172
 173                 p = (unsigned long *)(regs->fpregs + i);
 174
 175                 switch (regs->ftype[i]) {
 176                         case 1: type = 'f'; break;
 177                         case 2: type = 'd'; break;
 178                         case 3: type = 'e'; break;
 179                         default: type = '?'; break;
 180                 }
 181                 if (regs->init_flag)
 182                         type = '?';
 183
 184                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 185                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 186         }
 187
 188
 189         printk("FPSR: %08lx FPCR: %08lx\n",
 190                 (unsigned long)regs->fpsr,
 191                 (unsigned long)regs->fpcr);
 192 }
 193
 194 /*
 195  * Task structure and kernel stack allocation.
 196  */
 197 static unsigned long *thread_info_head;
 198 static unsigned int nr_thread_info;
 199
 200 extern unsigned long get_page_8k(int priority);
 201 extern void free_page_8k(unsigned long page);
 202
 203 // FIXME - is this valid?
 204 #define EXTRA_TASK_STRUCT       0
 205 #define ll_alloc_task_struct()  ((struct thread_info *)get_page_8k(GFP_KERNEL))
 206 #define ll_free_task_struct(p)  free_page_8k((unsigned long)(p))
 207
 208 //FIXME - do we use *task param below looks like we dont, which is ok?
 209 //FIXME - if EXTRA_TASK_STRUCT is zero we can optimise the below away permanently. *IF* its supposed to be zero.
 210 struct thread_info *alloc_thread_info(struct task_struct *task)
 211 {
 212         struct thread_info *thread = NULL;
 213
 214         if (EXTRA_TASK_STRUCT) {
 215                 unsigned long *p = thread_info_head;
 216
 217                 if (p) {
 218                         thread_info_head = (unsigned long *)p[0];
 219                         nr_thread_info -= 1;
 220                 }
 221                 thread = (struct thread_info *)p;
 222         }
 223
 224         if (!thread)
 225                 thread = ll_alloc_task_struct();
 226
 227 #ifdef CONFIG_MAGIC_SYSRQ
 228         /*
 229          * The stack must be cleared if you want SYSRQ-T to
 230          * give sensible stack usage information
 231          */
 232         if (thread) {
 233                 char *p = (char *)thread;
 234                 memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
 235         }
 236 #endif
 237         return thread;
 238 }
 239
 240 void free_thread_info(struct thread_info *thread)
 241 {
 242         if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
 243                 unsigned long *p = (unsigned long *)thread;
 244                 p[0] = (unsigned long)thread_info_head;
 245                 thread_info_head = p;
 246                 nr_thread_info += 1;
 247         } else
 248                 ll_free_task_struct(thread);
 249 }
 250
 251 /*
 252  * Free current thread data structures etc..
 253  */
 254 void exit_thread(void)
 255 {
 256 }
 257
 258 void flush_thread(void)
 259 {
 260         struct thread_info *thread = current_thread_info();
 261         struct task_struct *tsk = current;
 262
 263         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 264         memset(&thread->fpstate, 0, sizeof(union fp_state));
 265
 266         clear_used_math();
 267 }
 268
 269 void release_thread(struct task_struct *dead_task)
 270 {
 271 }
 272
 273 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 274
 275 int
 276 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 277             unsigned long unused, struct task_struct *p, struct pt_regs *regs)
 278 {
 279         struct thread_info *thread = task_thread_info(p);
 280         struct pt_regs *childregs = task_pt_regs(p);
 281
 282         *childregs = *regs;
 283         childregs->ARM_r0 = 0;
 284         childregs->ARM_sp = stack_start;
 285
 286         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 287         thread->cpu_context.sp = (unsigned long)childregs;
 288         thread->cpu_context.pc = (unsigned long)ret_from_fork | MODE_SVC26 | PSR_I_BIT;
 289
 290         return 0;
 291 }
 292
 293 /*
 294  * fill in the fpe structure for a core dump...
 295  */
 296 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 297 {
 298         struct thread_info *thread = current_thread_info();
 299         int used_math = !!used_math();
 300
 301         if (used_math)
 302                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 303
 304         return used_math;
 305 }
 306
 307 /*
 308  * fill in the user structure for a core dump..
 309  */
 310 void dump_thread(struct pt_regs * regs, struct user * dump)
 311 {
 312         struct task_struct *tsk = current;
 313
 314         dump->magic = CMAGIC;
 315         dump->start_code = tsk->mm->start_code;
 316         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 317
 318         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 319         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 320         dump->u_ssize = 0;
 321
 322         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 323         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 324         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn;
 325         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
 326         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 327
 328         if (dump->start_stack < 0x04000000)
 329                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 330
 331         dump->regs = *regs;
 332         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 333 }
 334
 335 /*
 336  * Shuffle the argument into the correct register before calling the
 337  * thread function.  r1 is the thread argument, r2 is the pointer to
 338  * the thread function, and r3 points to the exit function.
 339  * FIXME - make sure this is right - the older code used to zero fp
 340  * and cause the parent to call sys_exit (do_exit in this version)
 341  */
 342 extern void kernel_thread_helper(void);
 343
 344 asm(    ".section .text\n"
 345 "       .align\n"
 346 "       .type   kernel_thread_helper, #function\n"
 347 "kernel_thread_helper:\n"
 348 "       mov     r0, r1\n"
 349 "       mov     lr, r3\n"
 350 "       mov     pc, r2\n"
 351 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 352 "       .previous");
 353
 354 /*
 355  * Create a kernel thread.
 356  */
 357 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 358 {
 359         struct pt_regs regs;
 360
 361         memset(&regs, 0, sizeof(regs));
 362
 363         regs.ARM_r1 = (unsigned long)arg;
 364         regs.ARM_r2 = (unsigned long)fn;
 365         regs.ARM_r3 = (unsigned long)do_exit;
 366         regs.ARM_pc = (unsigned long)kernel_thread_helper | MODE_SVC26;
 367
 368         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 369 }
 370 EXPORT_SYMBOL(kernel_thread);
 371
 372
 373 unsigned long get_wchan(struct task_struct *p)
 374 {
 375         unsigned long fp, lr;
 376         unsigned long stack_page;
 377         int count = 0;
 378         if (!p || p == current || p->state == TASK_RUNNING)
 379                 return 0;
 380
 381         stack_page = 4096 + (unsigned long)p;
 382         fp = thread_saved_fp(p);
 383         do {
 384                 if (fp < stack_page || fp > 4092+stack_page)
 385                         return 0;
 386                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 387                 if (!in_sched_functions(lr))
 388                         return lr;
 389                 fp = *(unsigned long *) (fp - 12);
 390         } while (count ++ < 16);
 391         return 0;
 392 }