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