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/slab.h>
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/io.h>
  28 #include <asm/syscalls.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/mmu_context.h>
  32 #include <asm/fpu.h>
  33 #include <asm/switch_to.h>
  34
  35 struct task_struct *last_task_used_math = NULL;
  36 struct pt_regs fake_swapper_regs = { 0, };
  37
  38 void show_regs(struct pt_regs *regs)
  39 {
  40         unsigned long long ah, al, bh, bl, ch, cl;
  41
  42         printk("\n");
  43
  44         ah = (regs->pc) >> 32;
  45         al = (regs->pc) & 0xffffffff;
  46         bh = (regs->regs[18]) >> 32;
  47         bl = (regs->regs[18]) & 0xffffffff;
  48         ch = (regs->regs[15]) >> 32;
  49         cl = (regs->regs[15]) & 0xffffffff;
  50         printk("PC  : %08Lx%08Lx LINK: %08Lx%08Lx SP  : %08Lx%08Lx\n",
  51                ah, al, bh, bl, ch, cl);
  52
  53         ah = (regs->sr) >> 32;
  54         al = (regs->sr) & 0xffffffff;
  55         asm volatile ("getcon   " __TEA ", %0" : "=r" (bh));
  56         asm volatile ("getcon   " __TEA ", %0" : "=r" (bl));
  57         bh = (bh) >> 32;
  58         bl = (bl) & 0xffffffff;
  59         asm volatile ("getcon   " __KCR0 ", %0" : "=r" (ch));
  60         asm volatile ("getcon   " __KCR0 ", %0" : "=r" (cl));
  61         ch = (ch) >> 32;
  62         cl = (cl) & 0xffffffff;
  63         printk("SR  : %08Lx%08Lx TEA : %08Lx%08Lx KCR0: %08Lx%08Lx\n",
  64                ah, al, bh, bl, ch, cl);
  65
  66         ah = (regs->regs[0]) >> 32;
  67         al = (regs->regs[0]) & 0xffffffff;
  68         bh = (regs->regs[1]) >> 32;
  69         bl = (regs->regs[1]) & 0xffffffff;
  70         ch = (regs->regs[2]) >> 32;
  71         cl = (regs->regs[2]) & 0xffffffff;
  72         printk("R0  : %08Lx%08Lx R1  : %08Lx%08Lx R2  : %08Lx%08Lx\n",
  73                ah, al, bh, bl, ch, cl);
  74
  75         ah = (regs->regs[3]) >> 32;
  76         al = (regs->regs[3]) & 0xffffffff;
  77         bh = (regs->regs[4]) >> 32;
  78         bl = (regs->regs[4]) & 0xffffffff;
  79         ch = (regs->regs[5]) >> 32;
  80         cl = (regs->regs[5]) & 0xffffffff;
  81         printk("R3  : %08Lx%08Lx R4  : %08Lx%08Lx R5  : %08Lx%08Lx\n",
  82                ah, al, bh, bl, ch, cl);
  83
  84         ah = (regs->regs[6]) >> 32;
  85         al = (regs->regs[6]) & 0xffffffff;
  86         bh = (regs->regs[7]) >> 32;
  87         bl = (regs->regs[7]) & 0xffffffff;
  88         ch = (regs->regs[8]) >> 32;
  89         cl = (regs->regs[8]) & 0xffffffff;
  90         printk("R6  : %08Lx%08Lx R7  : %08Lx%08Lx R8  : %08Lx%08Lx\n",
  91                ah, al, bh, bl, ch, cl);
  92
  93         ah = (regs->regs[9]) >> 32;
  94         al = (regs->regs[9]) & 0xffffffff;
  95         bh = (regs->regs[10]) >> 32;
  96         bl = (regs->regs[10]) & 0xffffffff;
  97         ch = (regs->regs[11]) >> 32;
  98         cl = (regs->regs[11]) & 0xffffffff;
  99         printk("R9  : %08Lx%08Lx R10 : %08Lx%08Lx R11 : %08Lx%08Lx\n",
 100                ah, al, bh, bl, ch, cl);
 101
 102         ah = (regs->regs[12]) >> 32;
 103         al = (regs->regs[12]) & 0xffffffff;
 104         bh = (regs->regs[13]) >> 32;
 105         bl = (regs->regs[13]) & 0xffffffff;
 106         ch = (regs->regs[14]) >> 32;
 107         cl = (regs->regs[14]) & 0xffffffff;
 108         printk("R12 : %08Lx%08Lx R13 : %08Lx%08Lx R14 : %08Lx%08Lx\n",
 109                ah, al, bh, bl, ch, cl);
 110
 111         ah = (regs->regs[16]) >> 32;
 112         al = (regs->regs[16]) & 0xffffffff;
 113         bh = (regs->regs[17]) >> 32;
 114         bl = (regs->regs[17]) & 0xffffffff;
 115         ch = (regs->regs[19]) >> 32;
 116         cl = (regs->regs[19]) & 0xffffffff;
 117         printk("R16 : %08Lx%08Lx R17 : %08Lx%08Lx R19 : %08Lx%08Lx\n",
 118                ah, al, bh, bl, ch, cl);
 119
 120         ah = (regs->regs[20]) >> 32;
 121         al = (regs->regs[20]) & 0xffffffff;
 122         bh = (regs->regs[21]) >> 32;
 123         bl = (regs->regs[21]) & 0xffffffff;
 124         ch = (regs->regs[22]) >> 32;
 125         cl = (regs->regs[22]) & 0xffffffff;
 126         printk("R20 : %08Lx%08Lx R21 : %08Lx%08Lx R22 : %08Lx%08Lx\n",
 127                ah, al, bh, bl, ch, cl);
 128
 129         ah = (regs->regs[23]) >> 32;
 130         al = (regs->regs[23]) & 0xffffffff;
 131         bh = (regs->regs[24]) >> 32;
 132         bl = (regs->regs[24]) & 0xffffffff;
 133         ch = (regs->regs[25]) >> 32;
 134         cl = (regs->regs[25]) & 0xffffffff;
 135         printk("R23 : %08Lx%08Lx R24 : %08Lx%08Lx R25 : %08Lx%08Lx\n",
 136                ah, al, bh, bl, ch, cl);
 137
 138         ah = (regs->regs[26]) >> 32;
 139         al = (regs->regs[26]) & 0xffffffff;
 140         bh = (regs->regs[27]) >> 32;
 141         bl = (regs->regs[27]) & 0xffffffff;
 142         ch = (regs->regs[28]) >> 32;
 143         cl = (regs->regs[28]) & 0xffffffff;
 144         printk("R26 : %08Lx%08Lx R27 : %08Lx%08Lx R28 : %08Lx%08Lx\n",
 145                ah, al, bh, bl, ch, cl);
 146
 147         ah = (regs->regs[29]) >> 32;
 148         al = (regs->regs[29]) & 0xffffffff;
 149         bh = (regs->regs[30]) >> 32;
 150         bl = (regs->regs[30]) & 0xffffffff;
 151         ch = (regs->regs[31]) >> 32;
 152         cl = (regs->regs[31]) & 0xffffffff;
 153         printk("R29 : %08Lx%08Lx R30 : %08Lx%08Lx R31 : %08Lx%08Lx\n",
 154                ah, al, bh, bl, ch, cl);
 155
 156         ah = (regs->regs[32]) >> 32;
 157         al = (regs->regs[32]) & 0xffffffff;
 158         bh = (regs->regs[33]) >> 32;
 159         bl = (regs->regs[33]) & 0xffffffff;
 160         ch = (regs->regs[34]) >> 32;
 161         cl = (regs->regs[34]) & 0xffffffff;
 162         printk("R32 : %08Lx%08Lx R33 : %08Lx%08Lx R34 : %08Lx%08Lx\n",
 163                ah, al, bh, bl, ch, cl);
 164
 165         ah = (regs->regs[35]) >> 32;
 166         al = (regs->regs[35]) & 0xffffffff;
 167         bh = (regs->regs[36]) >> 32;
 168         bl = (regs->regs[36]) & 0xffffffff;
 169         ch = (regs->regs[37]) >> 32;
 170         cl = (regs->regs[37]) & 0xffffffff;
 171         printk("R35 : %08Lx%08Lx R36 : %08Lx%08Lx R37 : %08Lx%08Lx\n",
 172                ah, al, bh, bl, ch, cl);
 173
 174         ah = (regs->regs[38]) >> 32;
 175         al = (regs->regs[38]) & 0xffffffff;
 176         bh = (regs->regs[39]) >> 32;
 177         bl = (regs->regs[39]) & 0xffffffff;
 178         ch = (regs->regs[40]) >> 32;
 179         cl = (regs->regs[40]) & 0xffffffff;
 180         printk("R38 : %08Lx%08Lx R39 : %08Lx%08Lx R40 : %08Lx%08Lx\n",
 181                ah, al, bh, bl, ch, cl);
 182
 183         ah = (regs->regs[41]) >> 32;
 184         al = (regs->regs[41]) & 0xffffffff;
 185         bh = (regs->regs[42]) >> 32;
 186         bl = (regs->regs[42]) & 0xffffffff;
 187         ch = (regs->regs[43]) >> 32;
 188         cl = (regs->regs[43]) & 0xffffffff;
 189         printk("R41 : %08Lx%08Lx R42 : %08Lx%08Lx R43 : %08Lx%08Lx\n",
 190                ah, al, bh, bl, ch, cl);
 191
 192         ah = (regs->regs[44]) >> 32;
 193         al = (regs->regs[44]) & 0xffffffff;
 194         bh = (regs->regs[45]) >> 32;
 195         bl = (regs->regs[45]) & 0xffffffff;
 196         ch = (regs->regs[46]) >> 32;
 197         cl = (regs->regs[46]) & 0xffffffff;
 198         printk("R44 : %08Lx%08Lx R45 : %08Lx%08Lx R46 : %08Lx%08Lx\n",
 199                ah, al, bh, bl, ch, cl);
 200
 201         ah = (regs->regs[47]) >> 32;
 202         al = (regs->regs[47]) & 0xffffffff;
 203         bh = (regs->regs[48]) >> 32;
 204         bl = (regs->regs[48]) & 0xffffffff;
 205         ch = (regs->regs[49]) >> 32;
 206         cl = (regs->regs[49]) & 0xffffffff;
 207         printk("R47 : %08Lx%08Lx R48 : %08Lx%08Lx R49 : %08Lx%08Lx\n",
 208                ah, al, bh, bl, ch, cl);
 209
 210         ah = (regs->regs[50]) >> 32;
 211         al = (regs->regs[50]) & 0xffffffff;
 212         bh = (regs->regs[51]) >> 32;
 213         bl = (regs->regs[51]) & 0xffffffff;
 214         ch = (regs->regs[52]) >> 32;
 215         cl = (regs->regs[52]) & 0xffffffff;
 216         printk("R50 : %08Lx%08Lx R51 : %08Lx%08Lx R52 : %08Lx%08Lx\n",
 217                ah, al, bh, bl, ch, cl);
 218
 219         ah = (regs->regs[53]) >> 32;
 220         al = (regs->regs[53]) & 0xffffffff;
 221         bh = (regs->regs[54]) >> 32;
 222         bl = (regs->regs[54]) & 0xffffffff;
 223         ch = (regs->regs[55]) >> 32;
 224         cl = (regs->regs[55]) & 0xffffffff;
 225         printk("R53 : %08Lx%08Lx R54 : %08Lx%08Lx R55 : %08Lx%08Lx\n",
 226                ah, al, bh, bl, ch, cl);
 227
 228         ah = (regs->regs[56]) >> 32;
 229         al = (regs->regs[56]) & 0xffffffff;
 230         bh = (regs->regs[57]) >> 32;
 231         bl = (regs->regs[57]) & 0xffffffff;
 232         ch = (regs->regs[58]) >> 32;
 233         cl = (regs->regs[58]) & 0xffffffff;
 234         printk("R56 : %08Lx%08Lx R57 : %08Lx%08Lx R58 : %08Lx%08Lx\n",
 235                ah, al, bh, bl, ch, cl);
 236
 237         ah = (regs->regs[59]) >> 32;
 238         al = (regs->regs[59]) & 0xffffffff;
 239         bh = (regs->regs[60]) >> 32;
 240         bl = (regs->regs[60]) & 0xffffffff;
 241         ch = (regs->regs[61]) >> 32;
 242         cl = (regs->regs[61]) & 0xffffffff;
 243         printk("R59 : %08Lx%08Lx R60 : %08Lx%08Lx R61 : %08Lx%08Lx\n",
 244                ah, al, bh, bl, ch, cl);
 245
 246         ah = (regs->regs[62]) >> 32;
 247         al = (regs->regs[62]) & 0xffffffff;
 248         bh = (regs->tregs[0]) >> 32;
 249         bl = (regs->tregs[0]) & 0xffffffff;
 250         ch = (regs->tregs[1]) >> 32;
 251         cl = (regs->tregs[1]) & 0xffffffff;
 252         printk("R62 : %08Lx%08Lx T0  : %08Lx%08Lx T1  : %08Lx%08Lx\n",
 253                ah, al, bh, bl, ch, cl);
 254
 255         ah = (regs->tregs[2]) >> 32;
 256         al = (regs->tregs[2]) & 0xffffffff;
 257         bh = (regs->tregs[3]) >> 32;
 258         bl = (regs->tregs[3]) & 0xffffffff;
 259         ch = (regs->tregs[4]) >> 32;
 260         cl = (regs->tregs[4]) & 0xffffffff;
 261         printk("T2  : %08Lx%08Lx T3  : %08Lx%08Lx T4  : %08Lx%08Lx\n",
 262                ah, al, bh, bl, ch, cl);
 263
 264         ah = (regs->tregs[5]) >> 32;
 265         al = (regs->tregs[5]) & 0xffffffff;
 266         bh = (regs->tregs[6]) >> 32;
 267         bl = (regs->tregs[6]) & 0xffffffff;
 268         ch = (regs->tregs[7]) >> 32;
 269         cl = (regs->tregs[7]) & 0xffffffff;
 270         printk("T5  : %08Lx%08Lx T6  : %08Lx%08Lx T7  : %08Lx%08Lx\n",
 271                ah, al, bh, bl, ch, cl);
 272
 273         /*
 274          * If we're in kernel mode, dump the stack too..
 275          */
 276         if (!user_mode(regs)) {
 277                 void show_stack(struct task_struct *tsk, unsigned long *sp);
 278                 unsigned long sp = regs->regs[15] & 0xffffffff;
 279                 struct task_struct *tsk = get_current();
 280
 281                 tsk->thread.kregs = regs;
 282
 283                 show_stack(tsk, (unsigned long *)sp);
 284         }
 285 }
 286
 287 /*
 288  * Create a kernel thread
 289  */
 290 __noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
 291 {
 292         do_exit(fn(arg));
 293 }
 294
 295 /*
 296  * This is the mechanism for creating a new kernel thread.
 297  *
 298  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 299  * who haven't done an "execve()") should use this: it will work within
 300  * a system call from a "real" process, but the process memory space will
 301  * not be freed until both the parent and the child have exited.
 302  */
 303 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 304 {
 305         struct pt_regs regs;
 306
 307         memset(&regs, 0, sizeof(regs));
 308         regs.regs[2] = (unsigned long)arg;
 309         regs.regs[3] = (unsigned long)fn;
 310
 311         regs.pc = (unsigned long)kernel_thread_helper;
 312         regs.sr = (1 << 30);
 313
 314         /* Ok, create the new process.. */
 315         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 316                       &regs, 0, NULL, NULL);
 317 }
 318 EXPORT_SYMBOL(kernel_thread);
 319
 320 /*
 321  * Free current thread data structures etc..
 322  */
 323 void exit_thread(void)
 324 {
 325         /*
 326          * See arch/sparc/kernel/process.c for the precedent for doing
 327          * this -- RPC.
 328          *
 329          * The SH-5 FPU save/restore approach relies on
 330          * last_task_used_math pointing to a live task_struct.  When
 331          * another task tries to use the FPU for the 1st time, the FPUDIS
 332          * trap handling (see arch/sh/kernel/cpu/sh5/fpu.c) will save the
 333          * existing FPU state to the FP regs field within
 334          * last_task_used_math before re-loading the new task's FPU state
 335          * (or initialising it if the FPU has been used before).  So if
 336          * last_task_used_math is stale, and its page has already been
 337          * re-allocated for another use, the consequences are rather
 338          * grim. Unless we null it here, there is no other path through
 339          * which it would get safely nulled.
 340          */
 341 #ifdef CONFIG_SH_FPU
 342         if (last_task_used_math == current) {
 343                 last_task_used_math = NULL;
 344         }
 345 #endif
 346 }
 347
 348 void flush_thread(void)
 349 {
 350
 351         /* Called by fs/exec.c (setup_new_exec) to remove traces of a
 352          * previously running executable. */
 353 #ifdef CONFIG_SH_FPU
 354         if (last_task_used_math == current) {
 355                 last_task_used_math = NULL;
 356         }
 357         /* Force FPU state to be reinitialised after exec */
 358         clear_used_math();
 359 #endif
 360
 361         /* if we are a kernel thread, about to change to user thread,
 362          * update kreg
 363          */
 364         if(current->thread.kregs==&fake_swapper_regs) {
 365           current->thread.kregs =
 366              ((struct pt_regs *)(THREAD_SIZE + (unsigned long) current) - 1);
 367           current->thread.uregs = current->thread.kregs;
 368         }
 369 }
 370
 371 void release_thread(struct task_struct *dead_task)
 372 {
 373         /* do nothing */
 374 }
 375
 376 /* Fill in the fpu structure for a core dump.. */
 377 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 378 {
 379 #ifdef CONFIG_SH_FPU
 380         int fpvalid;
 381         struct task_struct *tsk = current;
 382
 383         fpvalid = !!tsk_used_math(tsk);
 384         if (fpvalid) {
 385                 if (current == last_task_used_math) {
 386                         enable_fpu();
 387                         save_fpu(tsk);
 388                         disable_fpu();
 389                         last_task_used_math = 0;
 390                         regs->sr |= SR_FD;
 391                 }
 392
 393                 memcpy(fpu, &tsk->thread.xstate->hardfpu, sizeof(*fpu));
 394         }
 395
 396         return fpvalid;
 397 #else
 398         return 0; /* Task didn't use the fpu at all. */
 399 #endif
 400 }
 401 EXPORT_SYMBOL(dump_fpu);
 402
 403 asmlinkage void ret_from_fork(void);
 404
 405 int copy_thread(unsigned long clone_flags, unsigned long usp,
 406                 unsigned long unused,
 407                 struct task_struct *p, struct pt_regs *regs)
 408 {
 409         struct pt_regs *childregs;
 410
 411 #ifdef CONFIG_SH_FPU
 412         if(last_task_used_math == current) {
 413                 enable_fpu();
 414                 save_fpu(current);
 415                 disable_fpu();
 416                 last_task_used_math = NULL;
 417                 regs->sr |= SR_FD;
 418         }
 419 #endif
 420         /* Copy from sh version */
 421         childregs = (struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1;
 422
 423         *childregs = *regs;
 424
 425         /*
 426          * Sign extend the edited stack.
 427          * Note that thread.pc and thread.pc will stay
 428          * 32-bit wide and context switch must take care
 429          * of NEFF sign extension.
 430          */
 431         if (user_mode(regs)) {
 432                 childregs->regs[15] = neff_sign_extend(usp);
 433                 p->thread.uregs = childregs;
 434         } else {
 435                 childregs->regs[15] =
 436                         neff_sign_extend((unsigned long)task_stack_page(p) +
 437                                          THREAD_SIZE);
 438         }
 439
 440         childregs->regs[9] = 0; /* Set return value for child */
 441         childregs->sr |= SR_FD; /* Invalidate FPU flag */
 442
 443         p->thread.sp = (unsigned long) childregs;
 444         p->thread.pc = (unsigned long) ret_from_fork;
 445
 446         return 0;
 447 }
 448
 449 asmlinkage int sys_fork(unsigned long r2, unsigned long r3,
 450                         unsigned long r4, unsigned long r5,
 451                         unsigned long r6, unsigned long r7,
 452                         struct pt_regs *pregs)
 453 {
 454         return do_fork(SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
 455 }
 456
 457 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 458                          unsigned long r4, unsigned long r5,
 459                          unsigned long r6, unsigned long r7,
 460                          struct pt_regs *pregs)
 461 {
 462         if (!newsp)
 463                 newsp = pregs->regs[15];
 464         return do_fork(clone_flags, newsp, pregs, 0, 0, 0);
 465 }
 466
 467 /*
 468  * This is trivial, and on the face of it looks like it
 469  * could equally well be done in user mode.
 470  *
 471  * Not so, for quite unobvious reasons - register pressure.
 472  * In user mode vfork() cannot have a stack frame, and if
 473  * done by calling the "clone()" system call directly, you
 474  * do not have enough call-clobbered registers to hold all
 475  * the information you need.
 476  */
 477 asmlinkage int sys_vfork(unsigned long r2, unsigned long r3,
 478                          unsigned long r4, unsigned long r5,
 479                          unsigned long r6, unsigned long r7,
 480                          struct pt_regs *pregs)
 481 {
 482         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
 483 }
 484
 485 /*
 486  * sys_execve() executes a new program.
 487  */
 488 asmlinkage int sys_execve(const char *ufilename, char **uargv,
 489                           char **uenvp, unsigned long r5,
 490                           unsigned long r6, unsigned long r7,
 491                           struct pt_regs *pregs)
 492 {
 493         int error;
 494         char *filename;
 495
 496         filename = getname((char __user *)ufilename);
 497         error = PTR_ERR(filename);
 498         if (IS_ERR(filename))
 499                 goto out;
 500
 501         error = do_execve(filename,
 502                           (const char __user *const __user *)uargv,
 503                           (const char __user *const __user *)uenvp,
 504                           pregs);
 505         putname(filename);
 506 out:
 507         return error;
 508 }
 509
 510 #ifdef CONFIG_FRAME_POINTER
 511 static int in_sh64_switch_to(unsigned long pc)
 512 {
 513         extern char __sh64_switch_to_end;
 514         /* For a sleeping task, the PC is somewhere in the middle of the function,
 515            so we don't have to worry about masking the LSB off */
 516         return (pc >= (unsigned long) sh64_switch_to) &&
 517                (pc < (unsigned long) &__sh64_switch_to_end);
 518 }
 519 #endif
 520
 521 unsigned long get_wchan(struct task_struct *p)
 522 {
 523         unsigned long pc;
 524
 525         if (!p || p == current || p->state == TASK_RUNNING)
 526                 return 0;
 527
 528         /*
 529          * The same comment as on the Alpha applies here, too ...
 530          */
 531         pc = thread_saved_pc(p);
 532
 533 #ifdef CONFIG_FRAME_POINTER
 534         if (in_sh64_switch_to(pc)) {
 535                 unsigned long schedule_fp;
 536                 unsigned long sh64_switch_to_fp;
 537                 unsigned long schedule_caller_pc;
 538
 539                 sh64_switch_to_fp = (long) p->thread.sp;
 540                 /* r14 is saved at offset 4 in the sh64_switch_to frame */
 541                 schedule_fp = *(unsigned long *) (long)(sh64_switch_to_fp + 4);
 542
 543                 /* and the caller of 'schedule' is (currently!) saved at offset 24
 544                    in the frame of schedule (from disasm) */
 545                 schedule_caller_pc = *(unsigned long *) (long)(schedule_fp + 24);
 546                 return schedule_caller_pc;
 547         }
 548 #endif
 549         return pc;
 550 }