xref: /openbmc/linux/arch/sparc/kernel/process_32.c (revision 8fdff1dc) 
1 /*  linux/arch/sparc/kernel/process.c
2  *
3  *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
4  *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
5  */
6 
7 /*
8  * This file handles the architecture-dependent parts of process handling..
9  */
10 
11 #include <stdarg.h>
12 
13 #include <linux/errno.h>
14 #include <linux/module.h>
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/mm.h>
18 #include <linux/stddef.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/smp.h>
22 #include <linux/reboot.h>
23 #include <linux/delay.h>
24 #include <linux/pm.h>
25 #include <linux/init.h>
26 #include <linux/slab.h>
27 
28 #include <asm/auxio.h>
29 #include <asm/oplib.h>
30 #include <asm/uaccess.h>
31 #include <asm/page.h>
32 #include <asm/pgalloc.h>
33 #include <asm/pgtable.h>
34 #include <asm/delay.h>
35 #include <asm/processor.h>
36 #include <asm/psr.h>
37 #include <asm/elf.h>
38 #include <asm/prom.h>
39 #include <asm/unistd.h>
40 #include <asm/setup.h>
41 
42 /*
43  * Power management idle function
44  * Set in pm platform drivers (apc.c and pmc.c)
45  */
46 void (*pm_idle)(void);
47 EXPORT_SYMBOL(pm_idle);
48 
49 /*
50  * Power-off handler instantiation for pm.h compliance
51  * This is done via auxio, but could be used as a fallback
52  * handler when auxio is not present-- unused for now...
53  */
54 void (*pm_power_off)(void) = machine_power_off;
55 EXPORT_SYMBOL(pm_power_off);
56 
57 /*
58  * sysctl - toggle power-off restriction for serial console
59  * systems in machine_power_off()
60  */
61 int scons_pwroff = 1;
62 
63 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
64 
65 struct task_struct *last_task_used_math = NULL;
66 struct thread_info *current_set[NR_CPUS];
67 
68 /*
69  * the idle loop on a Sparc... ;)
70  */
71 void cpu_idle(void)
72 {
73 	set_thread_flag(TIF_POLLING_NRFLAG);
74 
75 	/* endless idle loop with no priority at all */
76 	for (;;) {
77 		while (!need_resched()) {
78 			if (pm_idle)
79 				(*pm_idle)();
80 			else
81 				cpu_relax();
82 		}
83 		schedule_preempt_disabled();
84 	}
85 }
86 
87 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
88 void machine_halt(void)
89 {
90 	local_irq_enable();
91 	mdelay(8);
92 	local_irq_disable();
93 	prom_halt();
94 	panic("Halt failed!");
95 }
96 
97 void machine_restart(char * cmd)
98 {
99 	char *p;
100 
101 	local_irq_enable();
102 	mdelay(8);
103 	local_irq_disable();
104 
105 	p = strchr (reboot_command, '\n');
106 	if (p) *p = 0;
107 	if (cmd)
108 		prom_reboot(cmd);
109 	if (*reboot_command)
110 		prom_reboot(reboot_command);
111 	prom_feval ("reset");
112 	panic("Reboot failed!");
113 }
114 
115 void machine_power_off(void)
116 {
117 	if (auxio_power_register &&
118 	    (strcmp(of_console_device->type, "serial") || scons_pwroff))
119 		*auxio_power_register |= AUXIO_POWER_OFF;
120 	machine_halt();
121 }
122 
123 void show_regs(struct pt_regs *r)
124 {
125 	struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
126 
127         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
128 	       r->psr, r->pc, r->npc, r->y, print_tainted());
129 	printk("PC: <%pS>\n", (void *) r->pc);
130 	printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
131 	       r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
132 	       r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
133 	printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
134 	       r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
135 	       r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
136 	printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
137 
138 	printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
139 	       rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
140 	       rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
141 	printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
142 	       rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
143 	       rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
144 }
145 
146 /*
147  * The show_stack is an external API which we do not use ourselves.
148  * The oops is printed in die_if_kernel.
149  */
150 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
151 {
152 	unsigned long pc, fp;
153 	unsigned long task_base;
154 	struct reg_window32 *rw;
155 	int count = 0;
156 
157 	if (tsk != NULL)
158 		task_base = (unsigned long) task_stack_page(tsk);
159 	else
160 		task_base = (unsigned long) current_thread_info();
161 
162 	fp = (unsigned long) _ksp;
163 	do {
164 		/* Bogus frame pointer? */
165 		if (fp < (task_base + sizeof(struct thread_info)) ||
166 		    fp >= (task_base + (PAGE_SIZE << 1)))
167 			break;
168 		rw = (struct reg_window32 *) fp;
169 		pc = rw->ins[7];
170 		printk("[%08lx : ", pc);
171 		printk("%pS ] ", (void *) pc);
172 		fp = rw->ins[6];
173 	} while (++count < 16);
174 	printk("\n");
175 }
176 
177 void dump_stack(void)
178 {
179 	unsigned long *ksp;
180 
181 	__asm__ __volatile__("mov	%%fp, %0"
182 			     : "=r" (ksp));
183 	show_stack(current, ksp);
184 }
185 
186 EXPORT_SYMBOL(dump_stack);
187 
188 /*
189  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
190  */
191 unsigned long thread_saved_pc(struct task_struct *tsk)
192 {
193 	return task_thread_info(tsk)->kpc;
194 }
195 
196 /*
197  * Free current thread data structures etc..
198  */
199 void exit_thread(void)
200 {
201 #ifndef CONFIG_SMP
202 	if(last_task_used_math == current) {
203 #else
204 	if (test_thread_flag(TIF_USEDFPU)) {
205 #endif
206 		/* Keep process from leaving FPU in a bogon state. */
207 		put_psr(get_psr() | PSR_EF);
208 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
209 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
210 #ifndef CONFIG_SMP
211 		last_task_used_math = NULL;
212 #else
213 		clear_thread_flag(TIF_USEDFPU);
214 #endif
215 	}
216 }
217 
218 void flush_thread(void)
219 {
220 	current_thread_info()->w_saved = 0;
221 
222 #ifndef CONFIG_SMP
223 	if(last_task_used_math == current) {
224 #else
225 	if (test_thread_flag(TIF_USEDFPU)) {
226 #endif
227 		/* Clean the fpu. */
228 		put_psr(get_psr() | PSR_EF);
229 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
230 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
231 #ifndef CONFIG_SMP
232 		last_task_used_math = NULL;
233 #else
234 		clear_thread_flag(TIF_USEDFPU);
235 #endif
236 	}
237 
238 	/* This task is no longer a kernel thread. */
239 	if (current->thread.flags & SPARC_FLAG_KTHREAD) {
240 		current->thread.flags &= ~SPARC_FLAG_KTHREAD;
241 
242 		/* We must fixup kregs as well. */
243 		/* XXX This was not fixed for ti for a while, worked. Unused? */
244 		current->thread.kregs = (struct pt_regs *)
245 		    (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
246 	}
247 }
248 
249 static inline struct sparc_stackf __user *
250 clone_stackframe(struct sparc_stackf __user *dst,
251 		 struct sparc_stackf __user *src)
252 {
253 	unsigned long size, fp;
254 	struct sparc_stackf *tmp;
255 	struct sparc_stackf __user *sp;
256 
257 	if (get_user(tmp, &src->fp))
258 		return NULL;
259 
260 	fp = (unsigned long) tmp;
261 	size = (fp - ((unsigned long) src));
262 	fp = (unsigned long) dst;
263 	sp = (struct sparc_stackf __user *)(fp - size);
264 
265 	/* do_fork() grabs the parent semaphore, we must release it
266 	 * temporarily so we can build the child clone stack frame
267 	 * without deadlocking.
268 	 */
269 	if (__copy_user(sp, src, size))
270 		sp = NULL;
271 	else if (put_user(fp, &sp->fp))
272 		sp = NULL;
273 
274 	return sp;
275 }
276 
277 asmlinkage int sparc_do_fork(unsigned long clone_flags,
278                              unsigned long stack_start,
279                              struct pt_regs *regs,
280                              unsigned long stack_size)
281 {
282 	unsigned long parent_tid_ptr, child_tid_ptr;
283 	unsigned long orig_i1 = regs->u_regs[UREG_I1];
284 	long ret;
285 
286 	parent_tid_ptr = regs->u_regs[UREG_I2];
287 	child_tid_ptr = regs->u_regs[UREG_I4];
288 
289 	ret = do_fork(clone_flags, stack_start, stack_size,
290 		      (int __user *) parent_tid_ptr,
291 		      (int __user *) child_tid_ptr);
292 
293 	/* If we get an error and potentially restart the system
294 	 * call, we're screwed because copy_thread() clobbered
295 	 * the parent's %o1.  So detect that case and restore it
296 	 * here.
297 	 */
298 	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
299 		regs->u_regs[UREG_I1] = orig_i1;
300 
301 	return ret;
302 }
303 
304 /* Copy a Sparc thread.  The fork() return value conventions
305  * under SunOS are nothing short of bletcherous:
306  * Parent -->  %o0 == childs  pid, %o1 == 0
307  * Child  -->  %o0 == parents pid, %o1 == 1
308  *
309  * NOTE: We have a separate fork kpsr/kwim because
310  *       the parent could change these values between
311  *       sys_fork invocation and when we reach here
312  *       if the parent should sleep while trying to
313  *       allocate the task_struct and kernel stack in
314  *       do_fork().
315  * XXX See comment above sys_vfork in sparc64. todo.
316  */
317 extern void ret_from_fork(void);
318 extern void ret_from_kernel_thread(void);
319 
320 int copy_thread(unsigned long clone_flags, unsigned long sp,
321 		unsigned long arg, struct task_struct *p)
322 {
323 	struct thread_info *ti = task_thread_info(p);
324 	struct pt_regs *childregs, *regs = current_pt_regs();
325 	char *new_stack;
326 
327 #ifndef CONFIG_SMP
328 	if(last_task_used_math == current) {
329 #else
330 	if (test_thread_flag(TIF_USEDFPU)) {
331 #endif
332 		put_psr(get_psr() | PSR_EF);
333 		fpsave(&p->thread.float_regs[0], &p->thread.fsr,
334 		       &p->thread.fpqueue[0], &p->thread.fpqdepth);
335 	}
336 
337 	/*
338 	 *  p->thread_info         new_stack   childregs stack bottom
339 	 *  !                      !           !             !
340 	 *  V                      V (stk.fr.) V  (pt_regs)  V
341 	 *  +----- - - - - - ------+===========+=============+
342 	 */
343 	new_stack = task_stack_page(p) + THREAD_SIZE;
344 	new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
345 	childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
346 
347 	/*
348 	 * A new process must start with interrupts closed in 2.5,
349 	 * because this is how Mingo's scheduler works (see schedule_tail
350 	 * and finish_arch_switch). If we do not do it, a timer interrupt hits
351 	 * before we unlock, attempts to re-take the rq->lock, and then we die.
352 	 * Thus, kpsr|=PSR_PIL.
353 	 */
354 	ti->ksp = (unsigned long) new_stack;
355 	p->thread.kregs = childregs;
356 
357 	if (unlikely(p->flags & PF_KTHREAD)) {
358 		extern int nwindows;
359 		unsigned long psr;
360 		memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
361 		p->thread.flags |= SPARC_FLAG_KTHREAD;
362 		p->thread.current_ds = KERNEL_DS;
363 		ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
364 		childregs->u_regs[UREG_G1] = sp; /* function */
365 		childregs->u_regs[UREG_G2] = arg;
366 		psr = childregs->psr = get_psr();
367 		ti->kpsr = psr | PSR_PIL;
368 		ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
369 		return 0;
370 	}
371 	memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
372 	childregs->u_regs[UREG_FP] = sp;
373 	p->thread.flags &= ~SPARC_FLAG_KTHREAD;
374 	p->thread.current_ds = USER_DS;
375 	ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
376 	ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
377 	ti->kwim = current->thread.fork_kwim;
378 
379 	if (sp != regs->u_regs[UREG_FP]) {
380 		struct sparc_stackf __user *childstack;
381 		struct sparc_stackf __user *parentstack;
382 
383 		/*
384 		 * This is a clone() call with supplied user stack.
385 		 * Set some valid stack frames to give to the child.
386 		 */
387 		childstack = (struct sparc_stackf __user *)
388 			(sp & ~0xfUL);
389 		parentstack = (struct sparc_stackf __user *)
390 			regs->u_regs[UREG_FP];
391 
392 #if 0
393 		printk("clone: parent stack:\n");
394 		show_stackframe(parentstack);
395 #endif
396 
397 		childstack = clone_stackframe(childstack, parentstack);
398 		if (!childstack)
399 			return -EFAULT;
400 
401 #if 0
402 		printk("clone: child stack:\n");
403 		show_stackframe(childstack);
404 #endif
405 
406 		childregs->u_regs[UREG_FP] = (unsigned long)childstack;
407 	}
408 
409 #ifdef CONFIG_SMP
410 	/* FPU must be disabled on SMP. */
411 	childregs->psr &= ~PSR_EF;
412 	clear_tsk_thread_flag(p, TIF_USEDFPU);
413 #endif
414 
415 	/* Set the return value for the child. */
416 	childregs->u_regs[UREG_I0] = current->pid;
417 	childregs->u_regs[UREG_I1] = 1;
418 
419 	/* Set the return value for the parent. */
420 	regs->u_regs[UREG_I1] = 0;
421 
422 	if (clone_flags & CLONE_SETTLS)
423 		childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
424 
425 	return 0;
426 }
427 
428 /*
429  * fill in the fpu structure for a core dump.
430  */
431 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
432 {
433 	if (used_math()) {
434 		memset(fpregs, 0, sizeof(*fpregs));
435 		fpregs->pr_q_entrysize = 8;
436 		return 1;
437 	}
438 #ifdef CONFIG_SMP
439 	if (test_thread_flag(TIF_USEDFPU)) {
440 		put_psr(get_psr() | PSR_EF);
441 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
442 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
443 		if (regs != NULL) {
444 			regs->psr &= ~(PSR_EF);
445 			clear_thread_flag(TIF_USEDFPU);
446 		}
447 	}
448 #else
449 	if (current == last_task_used_math) {
450 		put_psr(get_psr() | PSR_EF);
451 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
452 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
453 		if (regs != NULL) {
454 			regs->psr &= ~(PSR_EF);
455 			last_task_used_math = NULL;
456 		}
457 	}
458 #endif
459 	memcpy(&fpregs->pr_fr.pr_regs[0],
460 	       &current->thread.float_regs[0],
461 	       (sizeof(unsigned long) * 32));
462 	fpregs->pr_fsr = current->thread.fsr;
463 	fpregs->pr_qcnt = current->thread.fpqdepth;
464 	fpregs->pr_q_entrysize = 8;
465 	fpregs->pr_en = 1;
466 	if(fpregs->pr_qcnt != 0) {
467 		memcpy(&fpregs->pr_q[0],
468 		       &current->thread.fpqueue[0],
469 		       sizeof(struct fpq) * fpregs->pr_qcnt);
470 	}
471 	/* Zero out the rest. */
472 	memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
473 	       sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
474 	return 1;
475 }
476 
477 unsigned long get_wchan(struct task_struct *task)
478 {
479 	unsigned long pc, fp, bias = 0;
480 	unsigned long task_base = (unsigned long) task;
481         unsigned long ret = 0;
482 	struct reg_window32 *rw;
483 	int count = 0;
484 
485 	if (!task || task == current ||
486             task->state == TASK_RUNNING)
487 		goto out;
488 
489 	fp = task_thread_info(task)->ksp + bias;
490 	do {
491 		/* Bogus frame pointer? */
492 		if (fp < (task_base + sizeof(struct thread_info)) ||
493 		    fp >= (task_base + (2 * PAGE_SIZE)))
494 			break;
495 		rw = (struct reg_window32 *) fp;
496 		pc = rw->ins[7];
497 		if (!in_sched_functions(pc)) {
498 			ret = pc;
499 			goto out;
500 		}
501 		fp = rw->ins[6] + bias;
502 	} while (++count < 16);
503 
504 out:
505 	return ret;
506 }
507 
508