arch/sh/kernel/process.c

   1 /* $Id: process.c,v 1.28 2004/05/05 16:54:23 lethal Exp $
   2  *
   3  *  linux/arch/sh/kernel/process.c
   4  *
   5  *  Copyright (C) 1995  Linus Torvalds
   6  *
   7  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
   8  */
   9
  10 /*
  11  * This file handles the architecture-dependent parts of process handling..
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/unistd.h>
  16 #include <linux/mm.h>
  17 #include <linux/elfcore.h>
  18 #include <linux/a.out.h>
  19 #include <linux/slab.h>
  20 #include <linux/pm.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/platform.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/kexec.h>
  25
  26 #include <asm/io.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/mmu_context.h>
  29 #include <asm/elf.h>
  30
  31 static int hlt_counter=0;
  32
  33 int ubc_usercnt = 0;
  34
  35 #define HARD_IDLE_TIMEOUT (HZ / 3)
  36
  37 void (*pm_idle)(void);
  38
  39 void (*pm_power_off)(void);
  40 EXPORT_SYMBOL(pm_power_off);
  41
  42 void disable_hlt(void)
  43 {
  44         hlt_counter++;
  45 }
  46
  47 EXPORT_SYMBOL(disable_hlt);
  48
  49 void enable_hlt(void)
  50 {
  51         hlt_counter--;
  52 }
  53
  54 EXPORT_SYMBOL(enable_hlt);
  55
  56 void default_idle(void)
  57 {
  58         if (!hlt_counter)
  59                 cpu_sleep();
  60         else
  61                 cpu_relax();
  62 }
  63
  64 void cpu_idle(void)
  65 {
  66         /* endless idle loop with no priority at all */
  67         while (1) {
  68                 void (*idle)(void) = pm_idle;
  69
  70                 if (!idle)
  71                         idle = default_idle;
  72
  73                 while (!need_resched())
  74                         idle();
  75
  76                 preempt_enable_no_resched();
  77                 schedule();
  78                 preempt_disable();
  79         }
  80 }
  81
  82 void machine_restart(char * __unused)
  83 {
  84
  85 #ifdef CONFIG_KEXEC
  86         struct kimage *image;
  87         image = xchg(&kexec_image, 0);
  88         if (image) {
  89                 machine_shutdown();
  90                 machine_kexec(image);
  91         }
  92 #endif
  93
  94         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
  95         asm volatile("ldc %0, sr\n\t"
  96                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
  97 }
  98
  99 void machine_halt(void)
 100 {
 101         local_irq_disable();
 102
 103         while (1)
 104                 cpu_sleep();
 105 }
 106
 107 void machine_power_off(void)
 108 {
 109         if (pm_power_off)
 110                 pm_power_off();
 111 }
 112
 113 void show_regs(struct pt_regs * regs)
 114 {
 115         printk("\n");
 116         printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
 117         print_symbol("PC is at %s\n", regs->pc);
 118         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 119                regs->pc, regs->regs[15], regs->sr);
 120 #ifdef CONFIG_MMU
 121         printk("TEA : %08x    ", ctrl_inl(MMU_TEA));
 122 #else
 123         printk("                  ");
 124 #endif
 125         printk("%s\n", print_tainted());
 126
 127         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 128                regs->regs[0],regs->regs[1],
 129                regs->regs[2],regs->regs[3]);
 130         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 131                regs->regs[4],regs->regs[5],
 132                regs->regs[6],regs->regs[7]);
 133         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 134                regs->regs[8],regs->regs[9],
 135                regs->regs[10],regs->regs[11]);
 136         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 137                regs->regs[12],regs->regs[13],
 138                regs->regs[14]);
 139         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 140                regs->mach, regs->macl, regs->gbr, regs->pr);
 141
 142         /*
 143          * If we're in kernel mode, dump the stack too..
 144          */
 145         if (!user_mode(regs)) {
 146                 extern void show_task(unsigned long *sp);
 147                 unsigned long sp = regs->regs[15];
 148
 149                 show_task((unsigned long *)sp);
 150         }
 151 }
 152
 153 /*
 154  * Create a kernel thread
 155  */
 156
 157 /*
 158  * This is the mechanism for creating a new kernel thread.
 159  *
 160  */
 161 extern void kernel_thread_helper(void);
 162 __asm__(".align 5\n"
 163         "kernel_thread_helper:\n\t"
 164         "jsr    @r5\n\t"
 165         " nop\n\t"
 166         "mov.l  1f, r1\n\t"
 167         "jsr    @r1\n\t"
 168         " mov   r0, r4\n\t"
 169         ".align 2\n\t"
 170         "1:.long do_exit");
 171
 172 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 173 {       /* Don't use this in BL=1(cli).  Or else, CPU resets! */
 174         struct pt_regs regs;
 175
 176         memset(&regs, 0, sizeof(regs));
 177         regs.regs[4] = (unsigned long) arg;
 178         regs.regs[5] = (unsigned long) fn;
 179
 180         regs.pc = (unsigned long) kernel_thread_helper;
 181         regs.sr = (1 << 30);
 182
 183         /* Ok, create the new process.. */
 184         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 185 }
 186
 187 /*
 188  * Free current thread data structures etc..
 189  */
 190 void exit_thread(void)
 191 {
 192         if (current->thread.ubc_pc) {
 193                 current->thread.ubc_pc = 0;
 194                 ubc_usercnt -= 1;
 195         }
 196 }
 197
 198 void flush_thread(void)
 199 {
 200 #if defined(CONFIG_SH_FPU)
 201         struct task_struct *tsk = current;
 202         /* Forget lazy FPU state */
 203         clear_fpu(tsk, task_pt_regs(tsk));
 204         clear_used_math();
 205 #endif
 206 }
 207
 208 void release_thread(struct task_struct *dead_task)
 209 {
 210         /* do nothing */
 211 }
 212
 213 /* Fill in the fpu structure for a core dump.. */
 214 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 215 {
 216         int fpvalid = 0;
 217
 218 #if defined(CONFIG_SH_FPU)
 219         struct task_struct *tsk = current;
 220
 221         fpvalid = !!tsk_used_math(tsk);
 222         if (fpvalid) {
 223                 unlazy_fpu(tsk, regs);
 224                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 225         }
 226 #endif
 227
 228         return fpvalid;
 229 }
 230
 231 /*
 232  * Capture the user space registers if the task is not running (in user space)
 233  */
 234 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 235 {
 236         struct pt_regs ptregs;
 237
 238         ptregs = *task_pt_regs(tsk);
 239         elf_core_copy_regs(regs, &ptregs);
 240
 241         return 1;
 242 }
 243
 244 int
 245 dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *fpu)
 246 {
 247         int fpvalid = 0;
 248
 249 #if defined(CONFIG_SH_FPU)
 250         fpvalid = !!tsk_used_math(tsk);
 251         if (fpvalid) {
 252                 unlazy_fpu(tsk, task_pt_regs(tsk));
 253                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 254         }
 255 #endif
 256
 257         return fpvalid;
 258 }
 259
 260 asmlinkage void ret_from_fork(void);
 261
 262 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 263                 unsigned long unused,
 264                 struct task_struct *p, struct pt_regs *regs)
 265 {
 266         struct pt_regs *childregs;
 267 #if defined(CONFIG_SH_FPU)
 268         struct task_struct *tsk = current;
 269
 270         unlazy_fpu(tsk, regs);
 271         p->thread.fpu = tsk->thread.fpu;
 272         copy_to_stopped_child_used_math(p);
 273 #endif
 274
 275         childregs = task_pt_regs(p);
 276         *childregs = *regs;
 277
 278         if (user_mode(regs)) {
 279                 childregs->regs[15] = usp;
 280         } else {
 281                 childregs->regs[15] = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 282         }
 283         if (clone_flags & CLONE_SETTLS) {
 284                 childregs->gbr = childregs->regs[0];
 285         }
 286         childregs->regs[0] = 0; /* Set return value for child */
 287
 288         p->thread.sp = (unsigned long) childregs;
 289         p->thread.pc = (unsigned long) ret_from_fork;
 290
 291         p->thread.ubc_pc = 0;
 292
 293         return 0;
 294 }
 295
 296 /* Tracing by user break controller.  */
 297 static void
 298 ubc_set_tracing(int asid, unsigned long pc)
 299 {
 300         ctrl_outl(pc, UBC_BARA);
 301
 302         /* We don't have any ASID settings for the SH-2! */
 303         if (cpu_data->type != CPU_SH7604)
 304                 ctrl_outb(asid, UBC_BASRA);
 305
 306         ctrl_outl(0, UBC_BAMRA);
 307
 308         if (cpu_data->type == CPU_SH7729) {
 309                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 310                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 311         } else {
 312                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 313                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 314         }
 315 }
 316
 317 /*
 318  *      switch_to(x,y) should switch tasks from x to y.
 319  *
 320  */
 321 struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
 322 {
 323 #if defined(CONFIG_SH_FPU)
 324         unlazy_fpu(prev, task_pt_regs(prev));
 325 #endif
 326
 327 #ifdef CONFIG_PREEMPT
 328         {
 329                 unsigned long flags;
 330                 struct pt_regs *regs;
 331
 332                 local_irq_save(flags);
 333                 regs = task_pt_regs(prev);
 334                 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
 335                         int offset = (int)regs->regs[15];
 336
 337                         /* Reset stack pointer: clear critical region mark */
 338                         regs->regs[15] = regs->regs[1];
 339                         if (regs->pc < regs->regs[0])
 340                                 /* Go to rewind point */
 341                                 regs->pc = regs->regs[0] + offset;
 342                 }
 343                 local_irq_restore(flags);
 344         }
 345 #endif
 346
 347         /*
 348          * Restore the kernel mode register
 349          *      k7 (r7_bank1)
 350          */
 351         asm volatile("ldc       %0, r7_bank"
 352                      : /* no output */
 353                      : "r" (task_thread_info(next)));
 354
 355 #ifdef CONFIG_MMU
 356         /* If no tasks are using the UBC, we're done */
 357         if (ubc_usercnt == 0)
 358                 /* If no tasks are using the UBC, we're done */;
 359         else if (next->thread.ubc_pc && next->mm) {
 360                 ubc_set_tracing(next->mm->context & MMU_CONTEXT_ASID_MASK,
 361                                 next->thread.ubc_pc);
 362         } else {
 363                 ctrl_outw(0, UBC_BBRA);
 364                 ctrl_outw(0, UBC_BBRB);
 365         }
 366 #endif
 367
 368         return prev;
 369 }
 370
 371 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 372                         unsigned long r6, unsigned long r7,
 373                         struct pt_regs regs)
 374 {
 375 #ifdef CONFIG_MMU
 376         return do_fork(SIGCHLD, regs.regs[15], &regs, 0, NULL, NULL);
 377 #else
 378         /* fork almost works, enough to trick you into looking elsewhere :-( */
 379         return -EINVAL;
 380 #endif
 381 }
 382
 383 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 384                          unsigned long parent_tidptr,
 385                          unsigned long child_tidptr,
 386                          struct pt_regs regs)
 387 {
 388         if (!newsp)
 389                 newsp = regs.regs[15];
 390         return do_fork(clone_flags, newsp, &regs, 0,
 391                         (int __user *)parent_tidptr, (int __user *)child_tidptr);
 392 }
 393
 394 /*
 395  * This is trivial, and on the face of it looks like it
 396  * could equally well be done in user mode.
 397  *
 398  * Not so, for quite unobvious reasons - register pressure.
 399  * In user mode vfork() cannot have a stack frame, and if
 400  * done by calling the "clone()" system call directly, you
 401  * do not have enough call-clobbered registers to hold all
 402  * the information you need.
 403  */
 404 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 405                          unsigned long r6, unsigned long r7,
 406                          struct pt_regs regs)
 407 {
 408         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.regs[15], &regs,
 409                        0, NULL, NULL);
 410 }
 411
 412 /*
 413  * sys_execve() executes a new program.
 414  */
 415 asmlinkage int sys_execve(char *ufilename, char **uargv,
 416                           char **uenvp, unsigned long r7,
 417                           struct pt_regs regs)
 418 {
 419         int error;
 420         char *filename;
 421
 422         filename = getname((char __user *)ufilename);
 423         error = PTR_ERR(filename);
 424         if (IS_ERR(filename))
 425                 goto out;
 426
 427         error = do_execve(filename,
 428                           (char __user * __user *)uargv,
 429                           (char __user * __user *)uenvp,
 430                           &regs);
 431         if (error == 0) {
 432                 task_lock(current);
 433                 current->ptrace &= ~PT_DTRACE;
 434                 task_unlock(current);
 435         }
 436         putname(filename);
 437 out:
 438         return error;
 439 }
 440
 441 unsigned long get_wchan(struct task_struct *p)
 442 {
 443         unsigned long schedule_frame;
 444         unsigned long pc;
 445
 446         if (!p || p == current || p->state == TASK_RUNNING)
 447                 return 0;
 448
 449         /*
 450          * The same comment as on the Alpha applies here, too ...
 451          */
 452         pc = thread_saved_pc(p);
 453         if (in_sched_functions(pc)) {
 454                 schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
 455                 return (unsigned long)((unsigned long *)schedule_frame)[1];
 456         }
 457         return pc;
 458 }
 459
 460 asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
 461                                  unsigned long r6, unsigned long r7,
 462                                  struct pt_regs regs)
 463 {
 464         /* Clear tracing.  */
 465         ctrl_outw(0, UBC_BBRA);
 466         ctrl_outw(0, UBC_BBRB);
 467         current->thread.ubc_pc = 0;
 468         ubc_usercnt -= 1;
 469
 470         force_sig(SIGTRAP, current);
 471 }
 472
 473 asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
 474                                           unsigned long r6, unsigned long r7,
 475                                           struct pt_regs regs)
 476 {
 477         regs.pc -= 2;
 478         force_sig(SIGTRAP, current);
 479 }