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