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