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/kallsyms.h>
  23 #include <linux/kexec.h>
  24
  25 #include <asm/io.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/mmu_context.h>
  28 #include <asm/elf.h>
  29 #include <asm/ubc.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 thread_info *ti = task_thread_info(p);
 267         struct pt_regs *childregs;
 268 #if defined(CONFIG_SH_FPU)
 269         struct task_struct *tsk = current;
 270
 271         unlazy_fpu(tsk, regs);
 272         p->thread.fpu = tsk->thread.fpu;
 273         copy_to_stopped_child_used_math(p);
 274 #endif
 275
 276         childregs = task_pt_regs(p);
 277         *childregs = *regs;
 278
 279         if (user_mode(regs)) {
 280                 childregs->regs[15] = usp;
 281                 ti->addr_limit = USER_DS;
 282         } else {
 283                 childregs->regs[15] = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 284                 ti->addr_limit = KERNEL_DS;
 285         }
 286         if (clone_flags & CLONE_SETTLS) {
 287                 childregs->gbr = childregs->regs[0];
 288         }
 289         childregs->regs[0] = 0; /* Set return value for child */
 290
 291         p->thread.sp = (unsigned long) childregs;
 292         p->thread.pc = (unsigned long) ret_from_fork;
 293
 294         p->thread.ubc_pc = 0;
 295
 296         return 0;
 297 }
 298
 299 /* Tracing by user break controller.  */
 300 static void
 301 ubc_set_tracing(int asid, unsigned long pc)
 302 {
 303         ctrl_outl(pc, UBC_BARA);
 304
 305 #ifdef CONFIG_MMU
 306         /* We don't have any ASID settings for the SH-2! */
 307         if (cpu_data->type != CPU_SH7604)
 308                 ctrl_outb(asid, UBC_BASRA);
 309 #endif
 310
 311         ctrl_outl(0, UBC_BAMRA);
 312
 313         if (cpu_data->type == CPU_SH7729) {
 314                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 315                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 316         } else {
 317                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 318                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 319         }
 320 }
 321
 322 /*
 323  *      switch_to(x,y) should switch tasks from x to y.
 324  *
 325  */
 326 struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
 327 {
 328 #if defined(CONFIG_SH_FPU)
 329         unlazy_fpu(prev, task_pt_regs(prev));
 330 #endif
 331
 332 #ifdef CONFIG_PREEMPT
 333         {
 334                 unsigned long flags;
 335                 struct pt_regs *regs;
 336
 337                 local_irq_save(flags);
 338                 regs = task_pt_regs(prev);
 339                 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
 340                         int offset = (int)regs->regs[15];
 341
 342                         /* Reset stack pointer: clear critical region mark */
 343                         regs->regs[15] = regs->regs[1];
 344                         if (regs->pc < regs->regs[0])
 345                                 /* Go to rewind point */
 346                                 regs->pc = regs->regs[0] + offset;
 347                 }
 348                 local_irq_restore(flags);
 349         }
 350 #endif
 351
 352 #ifdef CONFIG_MMU
 353         /*
 354          * Restore the kernel mode register
 355          *      k7 (r7_bank1)
 356          */
 357         asm volatile("ldc       %0, r7_bank"
 358                      : /* no output */
 359                      : "r" (task_thread_info(next)));
 360 #endif
 361
 362         /* If no tasks are using the UBC, we're done */
 363         if (ubc_usercnt == 0)
 364                 /* If no tasks are using the UBC, we're done */;
 365         else if (next->thread.ubc_pc && next->mm) {
 366                 int asid = 0;
 367 #ifdef CONFIG_MMU
 368                 asid |= next->mm->context & MMU_CONTEXT_ASID_MASK;
 369 #endif
 370                 ubc_set_tracing(asid, next->thread.ubc_pc);
 371         } else {
 372                 ctrl_outw(0, UBC_BBRA);
 373                 ctrl_outw(0, UBC_BBRB);
 374         }
 375
 376         return prev;
 377 }
 378
 379 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 380                         unsigned long r6, unsigned long r7,
 381                         struct pt_regs regs)
 382 {
 383 #ifdef CONFIG_MMU
 384         return do_fork(SIGCHLD, regs.regs[15], &regs, 0, NULL, NULL);
 385 #else
 386         /* fork almost works, enough to trick you into looking elsewhere :-( */
 387         return -EINVAL;
 388 #endif
 389 }
 390
 391 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 392                          unsigned long parent_tidptr,
 393                          unsigned long child_tidptr,
 394                          struct pt_regs regs)
 395 {
 396         if (!newsp)
 397                 newsp = regs.regs[15];
 398         return do_fork(clone_flags, newsp, &regs, 0,
 399                         (int __user *)parent_tidptr, (int __user *)child_tidptr);
 400 }
 401
 402 /*
 403  * This is trivial, and on the face of it looks like it
 404  * could equally well be done in user mode.
 405  *
 406  * Not so, for quite unobvious reasons - register pressure.
 407  * In user mode vfork() cannot have a stack frame, and if
 408  * done by calling the "clone()" system call directly, you
 409  * do not have enough call-clobbered registers to hold all
 410  * the information you need.
 411  */
 412 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 413                          unsigned long r6, unsigned long r7,
 414                          struct pt_regs regs)
 415 {
 416         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.regs[15], &regs,
 417                        0, NULL, NULL);
 418 }
 419
 420 /*
 421  * sys_execve() executes a new program.
 422  */
 423 asmlinkage int sys_execve(char *ufilename, char **uargv,
 424                           char **uenvp, unsigned long r7,
 425                           struct pt_regs regs)
 426 {
 427         int error;
 428         char *filename;
 429
 430         filename = getname((char __user *)ufilename);
 431         error = PTR_ERR(filename);
 432         if (IS_ERR(filename))
 433                 goto out;
 434
 435         error = do_execve(filename,
 436                           (char __user * __user *)uargv,
 437                           (char __user * __user *)uenvp,
 438                           &regs);
 439         if (error == 0) {
 440                 task_lock(current);
 441                 current->ptrace &= ~PT_DTRACE;
 442                 task_unlock(current);
 443         }
 444         putname(filename);
 445 out:
 446         return error;
 447 }
 448
 449 unsigned long get_wchan(struct task_struct *p)
 450 {
 451         unsigned long schedule_frame;
 452         unsigned long pc;
 453
 454         if (!p || p == current || p->state == TASK_RUNNING)
 455                 return 0;
 456
 457         /*
 458          * The same comment as on the Alpha applies here, too ...
 459          */
 460         pc = thread_saved_pc(p);
 461         if (in_sched_functions(pc)) {
 462                 schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
 463                 return (unsigned long)((unsigned long *)schedule_frame)[1];
 464         }
 465         return pc;
 466 }
 467
 468 asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
 469                                  unsigned long r6, unsigned long r7,
 470                                  struct pt_regs regs)
 471 {
 472         /* Clear tracing.  */
 473         ctrl_outw(0, UBC_BBRA);
 474         ctrl_outw(0, UBC_BBRB);
 475         current->thread.ubc_pc = 0;
 476         ubc_usercnt -= 1;
 477
 478         force_sig(SIGTRAP, current);
 479 }
 480
 481 asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
 482                                           unsigned long r6, unsigned long r7,
 483                                           struct pt_regs regs)
 484 {
 485         regs.pc -= 2;
 486         force_sig(SIGTRAP, current);
 487 }