process_32.c revision a43cb95d547a061ed5bf1acb28e0f5fd575e26c1 
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 */
46void (*sparc_idle)(void);
47
48/*
49 * Power-off handler instantiation for pm.h compliance
50 * This is done via auxio, but could be used as a fallback
51 * handler when auxio is not present-- unused for now...
52 */
53void (*pm_power_off)(void) = machine_power_off;
54EXPORT_SYMBOL(pm_power_off);
55
56/*
57 * sysctl - toggle power-off restriction for serial console
58 * systems in machine_power_off()
59 */
60int scons_pwroff = 1;
61
62extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
63
64struct task_struct *last_task_used_math = NULL;
65struct thread_info *current_set[NR_CPUS];
66
67/* Idle loop support. */
68void arch_cpu_idle(void)
69{
70	if (sparc_idle)
71		(*sparc_idle)();
72	local_irq_enable();
73}
74
75/* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
76void machine_halt(void)
77{
78	local_irq_enable();
79	mdelay(8);
80	local_irq_disable();
81	prom_halt();
82	panic("Halt failed!");
83}
84
85void machine_restart(char * cmd)
86{
87	char *p;
88
89	local_irq_enable();
90	mdelay(8);
91	local_irq_disable();
92
93	p = strchr (reboot_command, '\n');
94	if (p) *p = 0;
95	if (cmd)
96		prom_reboot(cmd);
97	if (*reboot_command)
98		prom_reboot(reboot_command);
99	prom_feval ("reset");
100	panic("Reboot failed!");
101}
102
103void machine_power_off(void)
104{
105	if (auxio_power_register &&
106	    (strcmp(of_console_device->type, "serial") || scons_pwroff))
107		*auxio_power_register |= AUXIO_POWER_OFF;
108	machine_halt();
109}
110
111void show_regs(struct pt_regs *r)
112{
113	struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
114
115	show_regs_print_info(KERN_DEFAULT);
116
117        printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
118	       r->psr, r->pc, r->npc, r->y, print_tainted());
119	printk("PC: <%pS>\n", (void *) r->pc);
120	printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
121	       r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
122	       r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
123	printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
124	       r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
125	       r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
126	printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
127
128	printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
129	       rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
130	       rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
131	printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
132	       rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
133	       rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
134}
135
136/*
137 * The show_stack is an external API which we do not use ourselves.
138 * The oops is printed in die_if_kernel.
139 */
140void show_stack(struct task_struct *tsk, unsigned long *_ksp)
141{
142	unsigned long pc, fp;
143	unsigned long task_base;
144	struct reg_window32 *rw;
145	int count = 0;
146
147	if (!tsk)
148		tsk = current;
149
150	if (tsk == current && !_ksp)
151		__asm__ __volatile__("mov	%%fp, %0" : "=r" (_ksp));
152
153	task_base = (unsigned long) task_stack_page(tsk);
154	fp = (unsigned long) _ksp;
155	do {
156		/* Bogus frame pointer? */
157		if (fp < (task_base + sizeof(struct thread_info)) ||
158		    fp >= (task_base + (PAGE_SIZE << 1)))
159			break;
160		rw = (struct reg_window32 *) fp;
161		pc = rw->ins[7];
162		printk("[%08lx : ", pc);
163		printk("%pS ] ", (void *) pc);
164		fp = rw->ins[6];
165	} while (++count < 16);
166	printk("\n");
167}
168
169/*
170 * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
171 */
172unsigned long thread_saved_pc(struct task_struct *tsk)
173{
174	return task_thread_info(tsk)->kpc;
175}
176
177/*
178 * Free current thread data structures etc..
179 */
180void exit_thread(void)
181{
182#ifndef CONFIG_SMP
183	if(last_task_used_math == current) {
184#else
185	if (test_thread_flag(TIF_USEDFPU)) {
186#endif
187		/* Keep process from leaving FPU in a bogon state. */
188		put_psr(get_psr() | PSR_EF);
189		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
190		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
191#ifndef CONFIG_SMP
192		last_task_used_math = NULL;
193#else
194		clear_thread_flag(TIF_USEDFPU);
195#endif
196	}
197}
198
199void flush_thread(void)
200{
201	current_thread_info()->w_saved = 0;
202
203#ifndef CONFIG_SMP
204	if(last_task_used_math == current) {
205#else
206	if (test_thread_flag(TIF_USEDFPU)) {
207#endif
208		/* Clean the fpu. */
209		put_psr(get_psr() | PSR_EF);
210		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
211		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
212#ifndef CONFIG_SMP
213		last_task_used_math = NULL;
214#else
215		clear_thread_flag(TIF_USEDFPU);
216#endif
217	}
218
219	/* This task is no longer a kernel thread. */
220	if (current->thread.flags & SPARC_FLAG_KTHREAD) {
221		current->thread.flags &= ~SPARC_FLAG_KTHREAD;
222
223		/* We must fixup kregs as well. */
224		/* XXX This was not fixed for ti for a while, worked. Unused? */
225		current->thread.kregs = (struct pt_regs *)
226		    (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
227	}
228}
229
230static inline struct sparc_stackf __user *
231clone_stackframe(struct sparc_stackf __user *dst,
232		 struct sparc_stackf __user *src)
233{
234	unsigned long size, fp;
235	struct sparc_stackf *tmp;
236	struct sparc_stackf __user *sp;
237
238	if (get_user(tmp, &src->fp))
239		return NULL;
240
241	fp = (unsigned long) tmp;
242	size = (fp - ((unsigned long) src));
243	fp = (unsigned long) dst;
244	sp = (struct sparc_stackf __user *)(fp - size);
245
246	/* do_fork() grabs the parent semaphore, we must release it
247	 * temporarily so we can build the child clone stack frame
248	 * without deadlocking.
249	 */
250	if (__copy_user(sp, src, size))
251		sp = NULL;
252	else if (put_user(fp, &sp->fp))
253		sp = NULL;
254
255	return sp;
256}
257
258asmlinkage int sparc_do_fork(unsigned long clone_flags,
259                             unsigned long stack_start,
260                             struct pt_regs *regs,
261                             unsigned long stack_size)
262{
263	unsigned long parent_tid_ptr, child_tid_ptr;
264	unsigned long orig_i1 = regs->u_regs[UREG_I1];
265	long ret;
266
267	parent_tid_ptr = regs->u_regs[UREG_I2];
268	child_tid_ptr = regs->u_regs[UREG_I4];
269
270	ret = do_fork(clone_flags, stack_start, stack_size,
271		      (int __user *) parent_tid_ptr,
272		      (int __user *) child_tid_ptr);
273
274	/* If we get an error and potentially restart the system
275	 * call, we're screwed because copy_thread() clobbered
276	 * the parent's %o1.  So detect that case and restore it
277	 * here.
278	 */
279	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
280		regs->u_regs[UREG_I1] = orig_i1;
281
282	return ret;
283}
284
285/* Copy a Sparc thread.  The fork() return value conventions
286 * under SunOS are nothing short of bletcherous:
287 * Parent -->  %o0 == childs  pid, %o1 == 0
288 * Child  -->  %o0 == parents pid, %o1 == 1
289 *
290 * NOTE: We have a separate fork kpsr/kwim because
291 *       the parent could change these values between
292 *       sys_fork invocation and when we reach here
293 *       if the parent should sleep while trying to
294 *       allocate the task_struct and kernel stack in
295 *       do_fork().
296 * XXX See comment above sys_vfork in sparc64. todo.
297 */
298extern void ret_from_fork(void);
299extern void ret_from_kernel_thread(void);
300
301int copy_thread(unsigned long clone_flags, unsigned long sp,
302		unsigned long arg, struct task_struct *p)
303{
304	struct thread_info *ti = task_thread_info(p);
305	struct pt_regs *childregs, *regs = current_pt_regs();
306	char *new_stack;
307
308#ifndef CONFIG_SMP
309	if(last_task_used_math == current) {
310#else
311	if (test_thread_flag(TIF_USEDFPU)) {
312#endif
313		put_psr(get_psr() | PSR_EF);
314		fpsave(&p->thread.float_regs[0], &p->thread.fsr,
315		       &p->thread.fpqueue[0], &p->thread.fpqdepth);
316	}
317
318	/*
319	 *  p->thread_info         new_stack   childregs stack bottom
320	 *  !                      !           !             !
321	 *  V                      V (stk.fr.) V  (pt_regs)  V
322	 *  +----- - - - - - ------+===========+=============+
323	 */
324	new_stack = task_stack_page(p) + THREAD_SIZE;
325	new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
326	childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
327
328	/*
329	 * A new process must start with interrupts closed in 2.5,
330	 * because this is how Mingo's scheduler works (see schedule_tail
331	 * and finish_arch_switch). If we do not do it, a timer interrupt hits
332	 * before we unlock, attempts to re-take the rq->lock, and then we die.
333	 * Thus, kpsr|=PSR_PIL.
334	 */
335	ti->ksp = (unsigned long) new_stack;
336	p->thread.kregs = childregs;
337
338	if (unlikely(p->flags & PF_KTHREAD)) {
339		extern int nwindows;
340		unsigned long psr;
341		memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
342		p->thread.flags |= SPARC_FLAG_KTHREAD;
343		p->thread.current_ds = KERNEL_DS;
344		ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
345		childregs->u_regs[UREG_G1] = sp; /* function */
346		childregs->u_regs[UREG_G2] = arg;
347		psr = childregs->psr = get_psr();
348		ti->kpsr = psr | PSR_PIL;
349		ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
350		return 0;
351	}
352	memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
353	childregs->u_regs[UREG_FP] = sp;
354	p->thread.flags &= ~SPARC_FLAG_KTHREAD;
355	p->thread.current_ds = USER_DS;
356	ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
357	ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
358	ti->kwim = current->thread.fork_kwim;
359
360	if (sp != regs->u_regs[UREG_FP]) {
361		struct sparc_stackf __user *childstack;
362		struct sparc_stackf __user *parentstack;
363
364		/*
365		 * This is a clone() call with supplied user stack.
366		 * Set some valid stack frames to give to the child.
367		 */
368		childstack = (struct sparc_stackf __user *)
369			(sp & ~0xfUL);
370		parentstack = (struct sparc_stackf __user *)
371			regs->u_regs[UREG_FP];
372
373#if 0
374		printk("clone: parent stack:\n");
375		show_stackframe(parentstack);
376#endif
377
378		childstack = clone_stackframe(childstack, parentstack);
379		if (!childstack)
380			return -EFAULT;
381
382#if 0
383		printk("clone: child stack:\n");
384		show_stackframe(childstack);
385#endif
386
387		childregs->u_regs[UREG_FP] = (unsigned long)childstack;
388	}
389
390#ifdef CONFIG_SMP
391	/* FPU must be disabled on SMP. */
392	childregs->psr &= ~PSR_EF;
393	clear_tsk_thread_flag(p, TIF_USEDFPU);
394#endif
395
396	/* Set the return value for the child. */
397	childregs->u_regs[UREG_I0] = current->pid;
398	childregs->u_regs[UREG_I1] = 1;
399
400	/* Set the return value for the parent. */
401	regs->u_regs[UREG_I1] = 0;
402
403	if (clone_flags & CLONE_SETTLS)
404		childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
405
406	return 0;
407}
408
409/*
410 * fill in the fpu structure for a core dump.
411 */
412int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
413{
414	if (used_math()) {
415		memset(fpregs, 0, sizeof(*fpregs));
416		fpregs->pr_q_entrysize = 8;
417		return 1;
418	}
419#ifdef CONFIG_SMP
420	if (test_thread_flag(TIF_USEDFPU)) {
421		put_psr(get_psr() | PSR_EF);
422		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
423		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
424		if (regs != NULL) {
425			regs->psr &= ~(PSR_EF);
426			clear_thread_flag(TIF_USEDFPU);
427		}
428	}
429#else
430	if (current == last_task_used_math) {
431		put_psr(get_psr() | PSR_EF);
432		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
433		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
434		if (regs != NULL) {
435			regs->psr &= ~(PSR_EF);
436			last_task_used_math = NULL;
437		}
438	}
439#endif
440	memcpy(&fpregs->pr_fr.pr_regs[0],
441	       &current->thread.float_regs[0],
442	       (sizeof(unsigned long) * 32));
443	fpregs->pr_fsr = current->thread.fsr;
444	fpregs->pr_qcnt = current->thread.fpqdepth;
445	fpregs->pr_q_entrysize = 8;
446	fpregs->pr_en = 1;
447	if(fpregs->pr_qcnt != 0) {
448		memcpy(&fpregs->pr_q[0],
449		       &current->thread.fpqueue[0],
450		       sizeof(struct fpq) * fpregs->pr_qcnt);
451	}
452	/* Zero out the rest. */
453	memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
454	       sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
455	return 1;
456}
457
458unsigned long get_wchan(struct task_struct *task)
459{
460	unsigned long pc, fp, bias = 0;
461	unsigned long task_base = (unsigned long) task;
462        unsigned long ret = 0;
463	struct reg_window32 *rw;
464	int count = 0;
465
466	if (!task || task == current ||
467            task->state == TASK_RUNNING)
468		goto out;
469
470	fp = task_thread_info(task)->ksp + bias;
471	do {
472		/* Bogus frame pointer? */
473		if (fp < (task_base + sizeof(struct thread_info)) ||
474		    fp >= (task_base + (2 * PAGE_SIZE)))
475			break;
476		rw = (struct reg_window32 *) fp;
477		pc = rw->ins[7];
478		if (!in_sched_functions(pc)) {
479			ret = pc;
480			goto out;
481		}
482		fp = rw->ins[6] + bias;
483	} while (++count < 16);
484
485out:
486	return ret;
487}
488
489