arch/sh/kernel/process_64.c

   1 /*
   2  * arch/sh/kernel/process_64.c
   3  *
   4  * This file handles the architecture-dependent parts of process handling..
   5  *
   6  * Copyright (C) 2000, 2001  Paolo Alberelli
   7  * Copyright (C) 2003 - 2007  Paul Mundt
   8  * Copyright (C) 2003, 2004 Richard Curnow
   9  *
  10  * Started from SH3/4 version:
  11  *   Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
  12  *
  13  *   In turn started from i386 version:
  14  *     Copyright (C) 1995  Linus Torvalds
  15  *
  16  * This file is subject to the terms and conditions of the GNU General Public
  17  * License.  See the file "COPYING" in the main directory of this archive
  18  * for more details.
  19  */
  20 #include <linux/mm.h>
  21 #include <linux/fs.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/reboot.h>
  24 #include <linux/init.h>
  25 #include <linux/module.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/io.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/mmu_context.h>
  31
  32 struct task_struct *last_task_used_math = NULL;
  33
  34 static int hlt_counter = 1;
  35
  36 #define HARD_IDLE_TIMEOUT (HZ / 3)
  37
  38 void disable_hlt(void)
  39 {
  40         hlt_counter++;
  41 }
  42
  43 void enable_hlt(void)
  44 {
  45         hlt_counter--;
  46 }
  47
  48 static int __init nohlt_setup(char *__unused)
  49 {
  50         hlt_counter = 1;
  51         return 1;
  52 }
  53
  54 static int __init hlt_setup(char *__unused)
  55 {
  56         hlt_counter = 0;
  57         return 1;
  58 }
  59
  60 __setup("nohlt", nohlt_setup);
  61 __setup("hlt", hlt_setup);
  62
  63 static inline void hlt(void)
  64 {
  65         __asm__ __volatile__ ("sleep" : : : "memory");
  66 }
  67
  68 /*
  69  * The idle loop on a uniprocessor SH..
  70  */
  71 void cpu_idle(void)
  72 {
  73         /* endless idle loop with no priority at all */
  74         while (1) {
  75                 if (hlt_counter) {
  76                         while (!need_resched())
  77                                 cpu_relax();
  78                 } else {
  79                         local_irq_disable();
  80                         while (!need_resched()) {
  81                                 local_irq_enable();
  82                                 hlt();
  83                                 local_irq_disable();
  84                         }
  85                         local_irq_enable();
  86                 }
  87                 preempt_enable_no_resched();
  88                 schedule();
  89                 preempt_disable();
  90         }
  91
  92 }
  93
  94 void machine_restart(char * __unused)
  95 {
  96         extern void phys_stext(void);
  97
  98         phys_stext();
  99 }
 100
 101 void machine_halt(void)
 102 {
 103         for (;;);
 104 }
 105
 106 void machine_power_off(void)
 107 {
 108 #if 0
 109         /* Disable watchdog timer */
 110         ctrl_outl(0xa5000000, WTCSR);
 111         /* Configure deep standby on sleep */
 112         ctrl_outl(0x03, STBCR);
 113 #endif
 114
 115         __asm__ __volatile__ (
 116                 "sleep\n\t"
 117                 "synci\n\t"
 118                 "nop;nop;nop;nop\n\t"
 119         );
 120
 121         panic("Unexpected wakeup!\n");
 122 }
 123
 124 void (*pm_power_off)(void) = machine_power_off;
 125 EXPORT_SYMBOL(pm_power_off);
 126
 127 void show_regs(struct pt_regs * regs)
 128 {
 129         unsigned long long ah, al, bh, bl, ch, cl;
 130
 131         printk("\n");
 132
 133         ah = (regs->pc) >> 32;
 134         al = (regs->pc) & 0xffffffff;
 135         bh = (regs->regs[18]) >> 32;
 136         bl = (regs->regs[18]) & 0xffffffff;
 137         ch = (regs->regs[15]) >> 32;
 138         cl = (regs->regs[15]) & 0xffffffff;
 139         printk("PC  : %08Lx%08Lx LINK: %08Lx%08Lx SP  : %08Lx%08Lx\n",
 140                ah, al, bh, bl, ch, cl);
 141
 142         ah = (regs->sr) >> 32;
 143         al = (regs->sr) & 0xffffffff;
 144         asm volatile ("getcon   " __TEA ", %0" : "=r" (bh));
 145         asm volatile ("getcon   " __TEA ", %0" : "=r" (bl));
 146         bh = (bh) >> 32;
 147         bl = (bl) & 0xffffffff;
 148         asm volatile ("getcon   " __KCR0 ", %0" : "=r" (ch));
 149         asm volatile ("getcon   " __KCR0 ", %0" : "=r" (cl));
 150         ch = (ch) >> 32;
 151         cl = (cl) & 0xffffffff;
 152         printk("SR  : %08Lx%08Lx TEA : %08Lx%08Lx KCR0: %08Lx%08Lx\n",
 153                ah, al, bh, bl, ch, cl);
 154
 155         ah = (regs->regs[0]) >> 32;
 156         al = (regs->regs[0]) & 0xffffffff;
 157         bh = (regs->regs[1]) >> 32;
 158         bl = (regs->regs[1]) & 0xffffffff;
 159         ch = (regs->regs[2]) >> 32;
 160         cl = (regs->regs[2]) & 0xffffffff;
 161         printk("R0  : %08Lx%08Lx R1  : %08Lx%08Lx R2  : %08Lx%08Lx\n",
 162                ah, al, bh, bl, ch, cl);
 163
 164         ah = (regs->regs[3]) >> 32;
 165         al = (regs->regs[3]) & 0xffffffff;
 166         bh = (regs->regs[4]) >> 32;
 167         bl = (regs->regs[4]) & 0xffffffff;
 168         ch = (regs->regs[5]) >> 32;
 169         cl = (regs->regs[5]) & 0xffffffff;
 170         printk("R3  : %08Lx%08Lx R4  : %08Lx%08Lx R5  : %08Lx%08Lx\n",
 171                ah, al, bh, bl, ch, cl);
 172
 173         ah = (regs->regs[6]) >> 32;
 174         al = (regs->regs[6]) & 0xffffffff;
 175         bh = (regs->regs[7]) >> 32;
 176         bl = (regs->regs[7]) & 0xffffffff;
 177         ch = (regs->regs[8]) >> 32;
 178         cl = (regs->regs[8]) & 0xffffffff;
 179         printk("R6  : %08Lx%08Lx R7  : %08Lx%08Lx R8  : %08Lx%08Lx\n",
 180                ah, al, bh, bl, ch, cl);
 181
 182         ah = (regs->regs[9]) >> 32;
 183         al = (regs->regs[9]) & 0xffffffff;
 184         bh = (regs->regs[10]) >> 32;
 185         bl = (regs->regs[10]) & 0xffffffff;
 186         ch = (regs->regs[11]) >> 32;
 187         cl = (regs->regs[11]) & 0xffffffff;
 188         printk("R9  : %08Lx%08Lx R10 : %08Lx%08Lx R11 : %08Lx%08Lx\n",
 189                ah, al, bh, bl, ch, cl);
 190
 191         ah = (regs->regs[12]) >> 32;
 192         al = (regs->regs[12]) & 0xffffffff;
 193         bh = (regs->regs[13]) >> 32;
 194         bl = (regs->regs[13]) & 0xffffffff;
 195         ch = (regs->regs[14]) >> 32;
 196         cl = (regs->regs[14]) & 0xffffffff;
 197         printk("R12 : %08Lx%08Lx R13 : %08Lx%08Lx R14 : %08Lx%08Lx\n",
 198                ah, al, bh, bl, ch, cl);
 199
 200         ah = (regs->regs[16]) >> 32;
 201         al = (regs->regs[16]) & 0xffffffff;
 202         bh = (regs->regs[17]) >> 32;
 203         bl = (regs->regs[17]) & 0xffffffff;
 204         ch = (regs->regs[19]) >> 32;
 205         cl = (regs->regs[19]) & 0xffffffff;
 206         printk("R16 : %08Lx%08Lx R17 : %08Lx%08Lx R19 : %08Lx%08Lx\n",
 207                ah, al, bh, bl, ch, cl);
 208
 209         ah = (regs->regs[20]) >> 32;
 210         al = (regs->regs[20]) & 0xffffffff;
 211         bh = (regs->regs[21]) >> 32;
 212         bl = (regs->regs[21]) & 0xffffffff;
 213         ch = (regs->regs[22]) >> 32;
 214         cl = (regs->regs[22]) & 0xffffffff;
 215         printk("R20 : %08Lx%08Lx R21 : %08Lx%08Lx R22 : %08Lx%08Lx\n",
 216                ah, al, bh, bl, ch, cl);
 217
 218         ah = (regs->regs[23]) >> 32;
 219         al = (regs->regs[23]) & 0xffffffff;
 220         bh = (regs->regs[24]) >> 32;
 221         bl = (regs->regs[24]) & 0xffffffff;
 222         ch = (regs->regs[25]) >> 32;
 223         cl = (regs->regs[25]) & 0xffffffff;
 224         printk("R23 : %08Lx%08Lx R24 : %08Lx%08Lx R25 : %08Lx%08Lx\n",
 225                ah, al, bh, bl, ch, cl);
 226
 227         ah = (regs->regs[26]) >> 32;
 228         al = (regs->regs[26]) & 0xffffffff;
 229         bh = (regs->regs[27]) >> 32;
 230         bl = (regs->regs[27]) & 0xffffffff;
 231         ch = (regs->regs[28]) >> 32;
 232         cl = (regs->regs[28]) & 0xffffffff;
 233         printk("R26 : %08Lx%08Lx R27 : %08Lx%08Lx R28 : %08Lx%08Lx\n",
 234                ah, al, bh, bl, ch, cl);
 235
 236         ah = (regs->regs[29]) >> 32;
 237         al = (regs->regs[29]) & 0xffffffff;
 238         bh = (regs->regs[30]) >> 32;
 239         bl = (regs->regs[30]) & 0xffffffff;
 240         ch = (regs->regs[31]) >> 32;
 241         cl = (regs->regs[31]) & 0xffffffff;
 242         printk("R29 : %08Lx%08Lx R30 : %08Lx%08Lx R31 : %08Lx%08Lx\n",
 243                ah, al, bh, bl, ch, cl);
 244
 245         ah = (regs->regs[32]) >> 32;
 246         al = (regs->regs[32]) & 0xffffffff;
 247         bh = (regs->regs[33]) >> 32;
 248         bl = (regs->regs[33]) & 0xffffffff;
 249         ch = (regs->regs[34]) >> 32;
 250         cl = (regs->regs[34]) & 0xffffffff;
 251         printk("R32 : %08Lx%08Lx R33 : %08Lx%08Lx R34 : %08Lx%08Lx\n",
 252                ah, al, bh, bl, ch, cl);
 253
 254         ah = (regs->regs[35]) >> 32;
 255         al = (regs->regs[35]) & 0xffffffff;
 256         bh = (regs->regs[36]) >> 32;
 257         bl = (regs->regs[36]) & 0xffffffff;
 258         ch = (regs->regs[37]) >> 32;
 259         cl = (regs->regs[37]) & 0xffffffff;
 260         printk("R35 : %08Lx%08Lx R36 : %08Lx%08Lx R37 : %08Lx%08Lx\n",
 261                ah, al, bh, bl, ch, cl);
 262
 263         ah = (regs->regs[38]) >> 32;
 264         al = (regs->regs[38]) & 0xffffffff;
 265         bh = (regs->regs[39]) >> 32;
 266         bl = (regs->regs[39]) & 0xffffffff;
 267         ch = (regs->regs[40]) >> 32;
 268         cl = (regs->regs[40]) & 0xffffffff;
 269         printk("R38 : %08Lx%08Lx R39 : %08Lx%08Lx R40 : %08Lx%08Lx\n",
 270                ah, al, bh, bl, ch, cl);
 271
 272         ah = (regs->regs[41]) >> 32;
 273         al = (regs->regs[41]) & 0xffffffff;
 274         bh = (regs->regs[42]) >> 32;
 275         bl = (regs->regs[42]) & 0xffffffff;
 276         ch = (regs->regs[43]) >> 32;
 277         cl = (regs->regs[43]) & 0xffffffff;
 278         printk("R41 : %08Lx%08Lx R42 : %08Lx%08Lx R43 : %08Lx%08Lx\n",
 279                ah, al, bh, bl, ch, cl);
 280
 281         ah = (regs->regs[44]) >> 32;
 282         al = (regs->regs[44]) & 0xffffffff;
 283         bh = (regs->regs[45]) >> 32;
 284         bl = (regs->regs[45]) & 0xffffffff;
 285         ch = (regs->regs[46]) >> 32;
 286         cl = (regs->regs[46]) & 0xffffffff;
 287         printk("R44 : %08Lx%08Lx R45 : %08Lx%08Lx R46 : %08Lx%08Lx\n",
 288                ah, al, bh, bl, ch, cl);
 289
 290         ah = (regs->regs[47]) >> 32;
 291         al = (regs->regs[47]) & 0xffffffff;
 292         bh = (regs->regs[48]) >> 32;
 293         bl = (regs->regs[48]) & 0xffffffff;
 294         ch = (regs->regs[49]) >> 32;
 295         cl = (regs->regs[49]) & 0xffffffff;
 296         printk("R47 : %08Lx%08Lx R48 : %08Lx%08Lx R49 : %08Lx%08Lx\n",
 297                ah, al, bh, bl, ch, cl);
 298
 299         ah = (regs->regs[50]) >> 32;
 300         al = (regs->regs[50]) & 0xffffffff;
 301         bh = (regs->regs[51]) >> 32;
 302         bl = (regs->regs[51]) & 0xffffffff;
 303         ch = (regs->regs[52]) >> 32;
 304         cl = (regs->regs[52]) & 0xffffffff;
 305         printk("R50 : %08Lx%08Lx R51 : %08Lx%08Lx R52 : %08Lx%08Lx\n",
 306                ah, al, bh, bl, ch, cl);
 307
 308         ah = (regs->regs[53]) >> 32;
 309         al = (regs->regs[53]) & 0xffffffff;
 310         bh = (regs->regs[54]) >> 32;
 311         bl = (regs->regs[54]) & 0xffffffff;
 312         ch = (regs->regs[55]) >> 32;
 313         cl = (regs->regs[55]) & 0xffffffff;
 314         printk("R53 : %08Lx%08Lx R54 : %08Lx%08Lx R55 : %08Lx%08Lx\n",
 315                ah, al, bh, bl, ch, cl);
 316
 317         ah = (regs->regs[56]) >> 32;
 318         al = (regs->regs[56]) & 0xffffffff;
 319         bh = (regs->regs[57]) >> 32;
 320         bl = (regs->regs[57]) & 0xffffffff;
 321         ch = (regs->regs[58]) >> 32;
 322         cl = (regs->regs[58]) & 0xffffffff;
 323         printk("R56 : %08Lx%08Lx R57 : %08Lx%08Lx R58 : %08Lx%08Lx\n",
 324                ah, al, bh, bl, ch, cl);
 325
 326         ah = (regs->regs[59]) >> 32;
 327         al = (regs->regs[59]) & 0xffffffff;
 328         bh = (regs->regs[60]) >> 32;
 329         bl = (regs->regs[60]) & 0xffffffff;
 330         ch = (regs->regs[61]) >> 32;
 331         cl = (regs->regs[61]) & 0xffffffff;
 332         printk("R59 : %08Lx%08Lx R60 : %08Lx%08Lx R61 : %08Lx%08Lx\n",
 333                ah, al, bh, bl, ch, cl);
 334
 335         ah = (regs->regs[62]) >> 32;
 336         al = (regs->regs[62]) & 0xffffffff;
 337         bh = (regs->tregs[0]) >> 32;
 338         bl = (regs->tregs[0]) & 0xffffffff;
 339         ch = (regs->tregs[1]) >> 32;
 340         cl = (regs->tregs[1]) & 0xffffffff;
 341         printk("R62 : %08Lx%08Lx T0  : %08Lx%08Lx T1  : %08Lx%08Lx\n",
 342                ah, al, bh, bl, ch, cl);
 343
 344         ah = (regs->tregs[2]) >> 32;
 345         al = (regs->tregs[2]) & 0xffffffff;
 346         bh = (regs->tregs[3]) >> 32;
 347         bl = (regs->tregs[3]) & 0xffffffff;
 348         ch = (regs->tregs[4]) >> 32;
 349         cl = (regs->tregs[4]) & 0xffffffff;
 350         printk("T2  : %08Lx%08Lx T3  : %08Lx%08Lx T4  : %08Lx%08Lx\n",
 351                ah, al, bh, bl, ch, cl);
 352
 353         ah = (regs->tregs[5]) >> 32;
 354         al = (regs->tregs[5]) & 0xffffffff;
 355         bh = (regs->tregs[6]) >> 32;
 356         bl = (regs->tregs[6]) & 0xffffffff;
 357         ch = (regs->tregs[7]) >> 32;
 358         cl = (regs->tregs[7]) & 0xffffffff;
 359         printk("T5  : %08Lx%08Lx T6  : %08Lx%08Lx T7  : %08Lx%08Lx\n",
 360                ah, al, bh, bl, ch, cl);
 361
 362         /*
 363          * If we're in kernel mode, dump the stack too..
 364          */
 365         if (!user_mode(regs)) {
 366                 void show_stack(struct task_struct *tsk, unsigned long *sp);
 367                 unsigned long sp = regs->regs[15] & 0xffffffff;
 368                 struct task_struct *tsk = get_current();
 369
 370                 tsk->thread.kregs = regs;
 371
 372                 show_stack(tsk, (unsigned long *)sp);
 373         }
 374 }
 375
 376 struct task_struct * alloc_task_struct(void)
 377 {
 378         /* Get task descriptor pages */
 379         return (struct task_struct *)
 380                 __get_free_pages(GFP_KERNEL, get_order(THREAD_SIZE));
 381 }
 382
 383 void free_task_struct(struct task_struct *p)
 384 {
 385         free_pages((unsigned long) p, get_order(THREAD_SIZE));
 386 }
 387
 388 /*
 389  * Create a kernel thread
 390  */
 391 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
 392 {
 393         do_exit(fn(arg));
 394 }
 395
 396 /*
 397  * This is the mechanism for creating a new kernel thread.
 398  *
 399  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 400  * who haven't done an "execve()") should use this: it will work within
 401  * a system call from a "real" process, but the process memory space will
 402  * not be freed until both the parent and the child have exited.
 403  */
 404 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 405 {
 406         struct pt_regs regs;
 407
 408         memset(&regs, 0, sizeof(regs));
 409         regs.regs[2] = (unsigned long)arg;
 410         regs.regs[3] = (unsigned long)fn;
 411
 412         regs.pc = (unsigned long)kernel_thread_helper;
 413         regs.sr = (1 << 30);
 414
 415         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 416                        &regs, 0, NULL, NULL);
 417 }
 418
 419 /*
 420  * Free current thread data structures etc..
 421  */
 422 void exit_thread(void)
 423 {
 424         /*
 425          * See arch/sparc/kernel/process.c for the precedent for doing
 426          * this -- RPC.
 427          *
 428          * The SH-5 FPU save/restore approach relies on
 429          * last_task_used_math pointing to a live task_struct.  When
 430          * another task tries to use the FPU for the 1st time, the FPUDIS
 431          * trap handling (see arch/sh/kernel/cpu/sh5/fpu.c) will save the
 432          * existing FPU state to the FP regs field within
 433          * last_task_used_math before re-loading the new task's FPU state
 434          * (or initialising it if the FPU has been used before).  So if
 435          * last_task_used_math is stale, and its page has already been
 436          * re-allocated for another use, the consequences are rather
 437          * grim. Unless we null it here, there is no other path through
 438          * which it would get safely nulled.
 439          */
 440 #ifdef CONFIG_SH_FPU
 441         if (last_task_used_math == current) {
 442                 last_task_used_math = NULL;
 443         }
 444 #endif
 445 }
 446
 447 void flush_thread(void)
 448 {
 449
 450         /* Called by fs/exec.c (flush_old_exec) to remove traces of a
 451          * previously running executable. */
 452 #ifdef CONFIG_SH_FPU
 453         if (last_task_used_math == current) {
 454                 last_task_used_math = NULL;
 455         }
 456         /* Force FPU state to be reinitialised after exec */
 457         clear_used_math();
 458 #endif
 459
 460         /* if we are a kernel thread, about to change to user thread,
 461          * update kreg
 462          */
 463         if(current->thread.kregs==&fake_swapper_regs) {
 464           current->thread.kregs =
 465              ((struct pt_regs *)(THREAD_SIZE + (unsigned long) current) - 1);
 466           current->thread.uregs = current->thread.kregs;
 467         }
 468 }
 469
 470 void release_thread(struct task_struct *dead_task)
 471 {
 472         /* do nothing */
 473 }
 474
 475 /* Fill in the fpu structure for a core dump.. */
 476 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 477 {
 478 #ifdef CONFIG_SH_FPU
 479         int fpvalid;
 480         struct task_struct *tsk = current;
 481
 482         fpvalid = !!tsk_used_math(tsk);
 483         if (fpvalid) {
 484                 if (current == last_task_used_math) {
 485                         enable_fpu();
 486                         save_fpu(tsk, regs);
 487                         disable_fpu();
 488                         last_task_used_math = 0;
 489                         regs->sr |= SR_FD;
 490                 }
 491
 492                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 493         }
 494
 495         return fpvalid;
 496 #else
 497         return 0; /* Task didn't use the fpu at all. */
 498 #endif
 499 }
 500
 501 asmlinkage void ret_from_fork(void);
 502
 503 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 504                 unsigned long unused,
 505                 struct task_struct *p, struct pt_regs *regs)
 506 {
 507         struct pt_regs *childregs;
 508         unsigned long long se;                  /* Sign extension */
 509
 510 #ifdef CONFIG_SH_FPU
 511         if(last_task_used_math == current) {
 512                 enable_fpu();
 513                 save_fpu(current, regs);
 514                 disable_fpu();
 515                 last_task_used_math = NULL;
 516                 regs->sr |= SR_FD;
 517         }
 518 #endif
 519         /* Copy from sh version */
 520         childregs = (struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1;
 521
 522         *childregs = *regs;
 523
 524         if (user_mode(regs)) {
 525                 childregs->regs[15] = usp;
 526                 p->thread.uregs = childregs;
 527         } else {
 528                 childregs->regs[15] = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 529         }
 530
 531         childregs->regs[9] = 0; /* Set return value for child */
 532         childregs->sr |= SR_FD; /* Invalidate FPU flag */
 533
 534         p->thread.sp = (unsigned long) childregs;
 535         p->thread.pc = (unsigned long) ret_from_fork;
 536
 537         /*
 538          * Sign extend the edited stack.
 539          * Note that thread.pc and thread.pc will stay
 540          * 32-bit wide and context switch must take care
 541          * of NEFF sign extension.
 542          */
 543
 544         se = childregs->regs[15];
 545         se = (se & NEFF_SIGN) ? (se | NEFF_MASK) : se;
 546         childregs->regs[15] = se;
 547
 548         return 0;
 549 }
 550
 551 asmlinkage int sys_fork(unsigned long r2, unsigned long r3,
 552                         unsigned long r4, unsigned long r5,
 553                         unsigned long r6, unsigned long r7,
 554                         struct pt_regs *pregs)
 555 {
 556         return do_fork(SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
 557 }
 558
 559 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 560                          unsigned long r4, unsigned long r5,
 561                          unsigned long r6, unsigned long r7,
 562                          struct pt_regs *pregs)
 563 {
 564         if (!newsp)
 565                 newsp = pregs->regs[15];
 566         return do_fork(clone_flags, newsp, pregs, 0, 0, 0);
 567 }
 568
 569 /*
 570  * This is trivial, and on the face of it looks like it
 571  * could equally well be done in user mode.
 572  *
 573  * Not so, for quite unobvious reasons - register pressure.
 574  * In user mode vfork() cannot have a stack frame, and if
 575  * done by calling the "clone()" system call directly, you
 576  * do not have enough call-clobbered registers to hold all
 577  * the information you need.
 578  */
 579 asmlinkage int sys_vfork(unsigned long r2, unsigned long r3,
 580                          unsigned long r4, unsigned long r5,
 581                          unsigned long r6, unsigned long r7,
 582                          struct pt_regs *pregs)
 583 {
 584         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
 585 }
 586
 587 /*
 588  * sys_execve() executes a new program.
 589  */
 590 asmlinkage int sys_execve(char *ufilename, char **uargv,
 591                           char **uenvp, unsigned long r5,
 592                           unsigned long r6, unsigned long r7,
 593                           struct pt_regs *pregs)
 594 {
 595         int error;
 596         char *filename;
 597
 598         lock_kernel();
 599         filename = getname((char __user *)ufilename);
 600         error = PTR_ERR(filename);
 601         if (IS_ERR(filename))
 602                 goto out;
 603
 604         error = do_execve(filename,
 605                           (char __user * __user *)uargv,
 606                           (char __user * __user *)uenvp,
 607                           pregs);
 608         if (error == 0) {
 609                 task_lock(current);
 610                 current->ptrace &= ~PT_DTRACE;
 611                 task_unlock(current);
 612         }
 613         putname(filename);
 614 out:
 615         unlock_kernel();
 616         return error;
 617 }
 618
 619 /*
 620  * These bracket the sleeping functions..
 621  */
 622 extern void interruptible_sleep_on(wait_queue_head_t *q);
 623
 624 #define mid_sched       ((unsigned long) interruptible_sleep_on)
 625
 626 #ifdef CONFIG_FRAME_POINTER
 627 static int in_sh64_switch_to(unsigned long pc)
 628 {
 629         extern char __sh64_switch_to_end;
 630         /* For a sleeping task, the PC is somewhere in the middle of the function,
 631            so we don't have to worry about masking the LSB off */
 632         return (pc >= (unsigned long) sh64_switch_to) &&
 633                (pc < (unsigned long) &__sh64_switch_to_end);
 634 }
 635 #endif
 636
 637 unsigned long get_wchan(struct task_struct *p)
 638 {
 639         unsigned long pc;
 640
 641         if (!p || p == current || p->state == TASK_RUNNING)
 642                 return 0;
 643
 644         /*
 645          * The same comment as on the Alpha applies here, too ...
 646          */
 647         pc = thread_saved_pc(p);
 648
 649 #ifdef CONFIG_FRAME_POINTER
 650         if (in_sh64_switch_to(pc)) {
 651                 unsigned long schedule_fp;
 652                 unsigned long sh64_switch_to_fp;
 653                 unsigned long schedule_caller_pc;
 654
 655                 sh64_switch_to_fp = (long) p->thread.sp;
 656                 /* r14 is saved at offset 4 in the sh64_switch_to frame */
 657                 schedule_fp = *(unsigned long *) (long)(sh64_switch_to_fp + 4);
 658
 659                 /* and the caller of 'schedule' is (currently!) saved at offset 24
 660                    in the frame of schedule (from disasm) */
 661                 schedule_caller_pc = *(unsigned long *) (long)(schedule_fp + 24);
 662                 return schedule_caller_pc;
 663         }
 664 #endif
 665         return pc;
 666 }
 667
 668 /* Provide a /proc/asids file that lists out the
 669    ASIDs currently associated with the processes.  (If the DM.PC register is
 670    examined through the debug link, this shows ASID + PC.  To make use of this,
 671    the PID->ASID relationship needs to be known.  This is primarily for
 672    debugging.)
 673    */
 674
 675 #if defined(CONFIG_SH64_PROC_ASIDS)
 676 static int
 677 asids_proc_info(char *buf, char **start, off_t fpos, int length, int *eof, void *data)
 678 {
 679         int len=0;
 680         struct task_struct *p;
 681         read_lock(&tasklist_lock);
 682         for_each_process(p) {
 683                 int pid = p->pid;
 684
 685                 if (!pid)
 686                         continue;
 687                 if (p->mm)
 688                         len += sprintf(buf+len, "%5d : %02lx\n", pid,
 689                                        asid_cache(smp_processor_id()));
 690                 else
 691                         len += sprintf(buf+len, "%5d : (none)\n", pid);
 692         }
 693         read_unlock(&tasklist_lock);
 694         *eof = 1;
 695         return len;
 696 }
 697
 698 static int __init register_proc_asids(void)
 699 {
 700         create_proc_read_entry("asids", 0, NULL, asids_proc_info, NULL);
 701         return 0;
 702 }
 703 __initcall(register_proc_asids);
 704 #endif