xref: /linux/arch/sparc/kernel/process_32.c (revision bb1c928df78ee6e3665a0d013e74108cc9abf34b)
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/elfcore.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/sched/debug.h>
18 #include <linux/sched/task.h>
19 #include <linux/sched/task_stack.h>
20 #include <linux/kernel.h>
21 #include <linux/mm.h>
22 #include <linux/stddef.h>
23 #include <linux/ptrace.h>
24 #include <linux/user.h>
25 #include <linux/smp.h>
26 #include <linux/reboot.h>
27 #include <linux/delay.h>
28 #include <linux/pm.h>
29 #include <linux/slab.h>
30 #include <linux/cpu.h>
31 
32 #include <asm/auxio.h>
33 #include <asm/oplib.h>
34 #include <linux/uaccess.h>
35 #include <asm/page.h>
36 #include <asm/pgalloc.h>
37 #include <asm/pgtable.h>
38 #include <asm/delay.h>
39 #include <asm/processor.h>
40 #include <asm/psr.h>
41 #include <asm/elf.h>
42 #include <asm/prom.h>
43 #include <asm/unistd.h>
44 #include <asm/setup.h>
45 
46 #include "kernel.h"
47 
48 /*
49  * Power management idle function
50  * Set in pm platform drivers (apc.c and pmc.c)
51  */
52 void (*sparc_idle)(void);
53 
54 /*
55  * Power-off handler instantiation for pm.h compliance
56  * This is done via auxio, but could be used as a fallback
57  * handler when auxio is not present-- unused for now...
58  */
59 void (*pm_power_off)(void) = machine_power_off;
60 EXPORT_SYMBOL(pm_power_off);
61 
62 /*
63  * sysctl - toggle power-off restriction for serial console
64  * systems in machine_power_off()
65  */
66 int scons_pwroff = 1;
67 
68 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
69 
70 struct task_struct *last_task_used_math = NULL;
71 struct thread_info *current_set[NR_CPUS];
72 
73 /* Idle loop support. */
74 void arch_cpu_idle(void)
75 {
76 	if (sparc_idle)
77 		(*sparc_idle)();
78 	local_irq_enable();
79 }
80 
81 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
82 void machine_halt(void)
83 {
84 	local_irq_enable();
85 	mdelay(8);
86 	local_irq_disable();
87 	prom_halt();
88 	panic("Halt failed!");
89 }
90 
91 void machine_restart(char * cmd)
92 {
93 	char *p;
94 
95 	local_irq_enable();
96 	mdelay(8);
97 	local_irq_disable();
98 
99 	p = strchr (reboot_command, '\n');
100 	if (p) *p = 0;
101 	if (cmd)
102 		prom_reboot(cmd);
103 	if (*reboot_command)
104 		prom_reboot(reboot_command);
105 	prom_feval ("reset");
106 	panic("Reboot failed!");
107 }
108 
109 void machine_power_off(void)
110 {
111 	if (auxio_power_register &&
112 	    (strcmp(of_console_device->type, "serial") || scons_pwroff)) {
113 		u8 power_register = sbus_readb(auxio_power_register);
114 		power_register |= AUXIO_POWER_OFF;
115 		sbus_writeb(power_register, auxio_power_register);
116 	}
117 
118 	machine_halt();
119 }
120 
121 void show_regs(struct pt_regs *r)
122 {
123 	struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
124 
125 	show_regs_print_info(KERN_DEFAULT);
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)
158 		tsk = current;
159 
160 	if (tsk == current && !_ksp)
161 		__asm__ __volatile__("mov	%%fp, %0" : "=r" (_ksp));
162 
163 	task_base = (unsigned long) task_stack_page(tsk);
164 	fp = (unsigned long) _ksp;
165 	do {
166 		/* Bogus frame pointer? */
167 		if (fp < (task_base + sizeof(struct thread_info)) ||
168 		    fp >= (task_base + (PAGE_SIZE << 1)))
169 			break;
170 		rw = (struct reg_window32 *) fp;
171 		pc = rw->ins[7];
172 		printk("[%08lx : ", pc);
173 		printk("%pS ] ", (void *) pc);
174 		fp = rw->ins[6];
175 	} while (++count < 16);
176 	printk("\n");
177 }
178 
179 /*
180  * Free current thread data structures etc..
181  */
182 void exit_thread(struct task_struct *tsk)
183 {
184 #ifndef CONFIG_SMP
185 	if (last_task_used_math == tsk) {
186 #else
187 	if (test_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU)) {
188 #endif
189 		/* Keep process from leaving FPU in a bogon state. */
190 		put_psr(get_psr() | PSR_EF);
191 		fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
192 		       &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
193 #ifndef CONFIG_SMP
194 		last_task_used_math = NULL;
195 #else
196 		clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
197 #endif
198 	}
199 }
200 
201 void flush_thread(void)
202 {
203 	current_thread_info()->w_saved = 0;
204 
205 #ifndef CONFIG_SMP
206 	if(last_task_used_math == current) {
207 #else
208 	if (test_thread_flag(TIF_USEDFPU)) {
209 #endif
210 		/* Clean the fpu. */
211 		put_psr(get_psr() | PSR_EF);
212 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
213 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
214 #ifndef CONFIG_SMP
215 		last_task_used_math = NULL;
216 #else
217 		clear_thread_flag(TIF_USEDFPU);
218 #endif
219 	}
220 
221 	/* This task is no longer a kernel thread. */
222 	if (current->thread.flags & SPARC_FLAG_KTHREAD) {
223 		current->thread.flags &= ~SPARC_FLAG_KTHREAD;
224 
225 		/* We must fixup kregs as well. */
226 		/* XXX This was not fixed for ti for a while, worked. Unused? */
227 		current->thread.kregs = (struct pt_regs *)
228 		    (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
229 	}
230 }
231 
232 static inline struct sparc_stackf __user *
233 clone_stackframe(struct sparc_stackf __user *dst,
234 		 struct sparc_stackf __user *src)
235 {
236 	unsigned long size, fp;
237 	struct sparc_stackf *tmp;
238 	struct sparc_stackf __user *sp;
239 
240 	if (get_user(tmp, &src->fp))
241 		return NULL;
242 
243 	fp = (unsigned long) tmp;
244 	size = (fp - ((unsigned long) src));
245 	fp = (unsigned long) dst;
246 	sp = (struct sparc_stackf __user *)(fp - size);
247 
248 	/* do_fork() grabs the parent semaphore, we must release it
249 	 * temporarily so we can build the child clone stack frame
250 	 * without deadlocking.
251 	 */
252 	if (__copy_user(sp, src, size))
253 		sp = NULL;
254 	else if (put_user(fp, &sp->fp))
255 		sp = NULL;
256 
257 	return sp;
258 }
259 
260 asmlinkage int sparc_do_fork(unsigned long clone_flags,
261                              unsigned long stack_start,
262                              struct pt_regs *regs,
263                              unsigned long stack_size)
264 {
265 	unsigned long parent_tid_ptr, child_tid_ptr;
266 	unsigned long orig_i1 = regs->u_regs[UREG_I1];
267 	long ret;
268 
269 	parent_tid_ptr = regs->u_regs[UREG_I2];
270 	child_tid_ptr = regs->u_regs[UREG_I4];
271 
272 	ret = do_fork(clone_flags, stack_start, stack_size,
273 		      (int __user *) parent_tid_ptr,
274 		      (int __user *) child_tid_ptr);
275 
276 	/* If we get an error and potentially restart the system
277 	 * call, we're screwed because copy_thread() clobbered
278 	 * the parent's %o1.  So detect that case and restore it
279 	 * here.
280 	 */
281 	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
282 		regs->u_regs[UREG_I1] = orig_i1;
283 
284 	return ret;
285 }
286 
287 /* Copy a Sparc thread.  The fork() return value conventions
288  * under SunOS are nothing short of bletcherous:
289  * Parent -->  %o0 == childs  pid, %o1 == 0
290  * Child  -->  %o0 == parents pid, %o1 == 1
291  *
292  * NOTE: We have a separate fork kpsr/kwim because
293  *       the parent could change these values between
294  *       sys_fork invocation and when we reach here
295  *       if the parent should sleep while trying to
296  *       allocate the task_struct and kernel stack in
297  *       do_fork().
298  * XXX See comment above sys_vfork in sparc64. todo.
299  */
300 extern void ret_from_fork(void);
301 extern void ret_from_kernel_thread(void);
302 
303 int copy_thread(unsigned long clone_flags, unsigned long sp,
304 		unsigned long arg, struct task_struct *p)
305 {
306 	struct thread_info *ti = task_thread_info(p);
307 	struct pt_regs *childregs, *regs = current_pt_regs();
308 	char *new_stack;
309 
310 #ifndef CONFIG_SMP
311 	if(last_task_used_math == current) {
312 #else
313 	if (test_thread_flag(TIF_USEDFPU)) {
314 #endif
315 		put_psr(get_psr() | PSR_EF);
316 		fpsave(&p->thread.float_regs[0], &p->thread.fsr,
317 		       &p->thread.fpqueue[0], &p->thread.fpqdepth);
318 	}
319 
320 	/*
321 	 *  p->thread_info         new_stack   childregs stack bottom
322 	 *  !                      !           !             !
323 	 *  V                      V (stk.fr.) V  (pt_regs)  V
324 	 *  +----- - - - - - ------+===========+=============+
325 	 */
326 	new_stack = task_stack_page(p) + THREAD_SIZE;
327 	new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
328 	childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
329 
330 	/*
331 	 * A new process must start with interrupts disabled, see schedule_tail()
332 	 * and finish_task_switch(). (If we do not do it and if a timer interrupt
333 	 * hits before we unlock and attempts to take the rq->lock, we deadlock.)
334 	 *
335 	 * Thus, kpsr |= PSR_PIL.
336 	 */
337 	ti->ksp = (unsigned long) new_stack;
338 	p->thread.kregs = childregs;
339 
340 	if (unlikely(p->flags & PF_KTHREAD)) {
341 		extern int nwindows;
342 		unsigned long psr;
343 		memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
344 		p->thread.flags |= SPARC_FLAG_KTHREAD;
345 		p->thread.current_ds = KERNEL_DS;
346 		ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
347 		childregs->u_regs[UREG_G1] = sp; /* function */
348 		childregs->u_regs[UREG_G2] = arg;
349 		psr = childregs->psr = get_psr();
350 		ti->kpsr = psr | PSR_PIL;
351 		ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
352 		return 0;
353 	}
354 	memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
355 	childregs->u_regs[UREG_FP] = sp;
356 	p->thread.flags &= ~SPARC_FLAG_KTHREAD;
357 	p->thread.current_ds = USER_DS;
358 	ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
359 	ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
360 	ti->kwim = current->thread.fork_kwim;
361 
362 	if (sp != regs->u_regs[UREG_FP]) {
363 		struct sparc_stackf __user *childstack;
364 		struct sparc_stackf __user *parentstack;
365 
366 		/*
367 		 * This is a clone() call with supplied user stack.
368 		 * Set some valid stack frames to give to the child.
369 		 */
370 		childstack = (struct sparc_stackf __user *)
371 			(sp & ~0xfUL);
372 		parentstack = (struct sparc_stackf __user *)
373 			regs->u_regs[UREG_FP];
374 
375 #if 0
376 		printk("clone: parent stack:\n");
377 		show_stackframe(parentstack);
378 #endif
379 
380 		childstack = clone_stackframe(childstack, parentstack);
381 		if (!childstack)
382 			return -EFAULT;
383 
384 #if 0
385 		printk("clone: child stack:\n");
386 		show_stackframe(childstack);
387 #endif
388 
389 		childregs->u_regs[UREG_FP] = (unsigned long)childstack;
390 	}
391 
392 #ifdef CONFIG_SMP
393 	/* FPU must be disabled on SMP. */
394 	childregs->psr &= ~PSR_EF;
395 	clear_tsk_thread_flag(p, TIF_USEDFPU);
396 #endif
397 
398 	/* Set the return value for the child. */
399 	childregs->u_regs[UREG_I0] = current->pid;
400 	childregs->u_regs[UREG_I1] = 1;
401 
402 	/* Set the return value for the parent. */
403 	regs->u_regs[UREG_I1] = 0;
404 
405 	if (clone_flags & CLONE_SETTLS)
406 		childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
407 
408 	return 0;
409 }
410 
411 /*
412  * fill in the fpu structure for a core dump.
413  */
414 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
415 {
416 	if (used_math()) {
417 		memset(fpregs, 0, sizeof(*fpregs));
418 		fpregs->pr_q_entrysize = 8;
419 		return 1;
420 	}
421 #ifdef CONFIG_SMP
422 	if (test_thread_flag(TIF_USEDFPU)) {
423 		put_psr(get_psr() | PSR_EF);
424 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
425 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
426 		if (regs != NULL) {
427 			regs->psr &= ~(PSR_EF);
428 			clear_thread_flag(TIF_USEDFPU);
429 		}
430 	}
431 #else
432 	if (current == last_task_used_math) {
433 		put_psr(get_psr() | PSR_EF);
434 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
435 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
436 		if (regs != NULL) {
437 			regs->psr &= ~(PSR_EF);
438 			last_task_used_math = NULL;
439 		}
440 	}
441 #endif
442 	memcpy(&fpregs->pr_fr.pr_regs[0],
443 	       &current->thread.float_regs[0],
444 	       (sizeof(unsigned long) * 32));
445 	fpregs->pr_fsr = current->thread.fsr;
446 	fpregs->pr_qcnt = current->thread.fpqdepth;
447 	fpregs->pr_q_entrysize = 8;
448 	fpregs->pr_en = 1;
449 	if(fpregs->pr_qcnt != 0) {
450 		memcpy(&fpregs->pr_q[0],
451 		       &current->thread.fpqueue[0],
452 		       sizeof(struct fpq) * fpregs->pr_qcnt);
453 	}
454 	/* Zero out the rest. */
455 	memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
456 	       sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
457 	return 1;
458 }
459 
460 unsigned long get_wchan(struct task_struct *task)
461 {
462 	unsigned long pc, fp, bias = 0;
463 	unsigned long task_base = (unsigned long) task;
464         unsigned long ret = 0;
465 	struct reg_window32 *rw;
466 	int count = 0;
467 
468 	if (!task || task == current ||
469             task->state == TASK_RUNNING)
470 		goto out;
471 
472 	fp = task_thread_info(task)->ksp + bias;
473 	do {
474 		/* Bogus frame pointer? */
475 		if (fp < (task_base + sizeof(struct thread_info)) ||
476 		    fp >= (task_base + (2 * PAGE_SIZE)))
477 			break;
478 		rw = (struct reg_window32 *) fp;
479 		pc = rw->ins[7];
480 		if (!in_sched_functions(pc)) {
481 			ret = pc;
482 			goto out;
483 		}
484 		fp = rw->ins[6] + bias;
485 	} while (++count < 16);
486 
487 out:
488 	return ret;
489 }
490 
491