1// SPDX-License-Identifier: GPL-2.0
2/*  linux/arch/sparc/kernel/process.c
3 *
4 *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
5 *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
6 */
7
8/*
9 * This file handles the architecture-dependent parts of process handling..
10 */
11#include <linux/elfcore.h>
12#include <linux/errno.h>
13#include <linux/module.h>
14#include <linux/sched.h>
15#include <linux/sched/debug.h>
16#include <linux/sched/task.h>
17#include <linux/sched/task_stack.h>
18#include <linux/kernel.h>
19#include <linux/mm.h>
20#include <linux/stddef.h>
21#include <linux/ptrace.h>
22#include <linux/user.h>
23#include <linux/smp.h>
24#include <linux/reboot.h>
25#include <linux/delay.h>
26#include <linux/pm.h>
27#include <linux/slab.h>
28#include <linux/cpu.h>
29
30#include <asm/auxio.h>
31#include <asm/oplib.h>
32#include <linux/uaccess.h>
33#include <asm/page.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#include "kernel.h"
43
44/*
45 * Power management idle function
46 * Set in pm platform drivers (apc.c and pmc.c)
47 */
48void (*sparc_idle)(void);
49
50/*
51 * Power-off handler instantiation for pm.h compliance
52 * This is done via auxio, but could be used as a fallback
53 * handler when auxio is not present-- unused for now...
54 */
55void (*pm_power_off)(void) = machine_power_off;
56EXPORT_SYMBOL(pm_power_off);
57
58/*
59 * sysctl - toggle power-off restriction for serial console
60 * systems in machine_power_off()
61 */
62int scons_pwroff = 1;
63
64extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
65
66struct task_struct *last_task_used_math = NULL;
67struct thread_info *current_set[NR_CPUS];
68
69/* Idle loop support. */
70void arch_cpu_idle(void)
71{
72	if (sparc_idle)
73		(*sparc_idle)();
74}
75
76/* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
77void machine_halt(void)
78{
79	local_irq_enable();
80	mdelay(8);
81	local_irq_disable();
82	prom_halt();
83	panic("Halt failed!");
84}
85
86void machine_restart(char * cmd)
87{
88	char *p;
89
90	local_irq_enable();
91	mdelay(8);
92	local_irq_disable();
93
94	p = strchr (reboot_command, '\n');
95	if (p) *p = 0;
96	if (cmd)
97		prom_reboot(cmd);
98	if (*reboot_command)
99		prom_reboot(reboot_command);
100	prom_feval ("reset");
101	panic("Reboot failed!");
102}
103
104void machine_power_off(void)
105{
106	if (auxio_power_register &&
107	    (!of_node_is_type(of_console_device, "serial") || scons_pwroff)) {
108		u8 power_register = sbus_readb(auxio_power_register);
109		power_register |= AUXIO_POWER_OFF;
110		sbus_writeb(power_register, auxio_power_register);
111	}
112
113	machine_halt();
114}
115
116void show_regs(struct pt_regs *r)
117{
118	struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
119
120	show_regs_print_info(KERN_DEFAULT);
121
122        printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
123	       r->psr, r->pc, r->npc, r->y, print_tainted());
124	printk("PC: <%pS>\n", (void *) r->pc);
125	printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
126	       r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
127	       r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
128	printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
129	       r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
130	       r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
131	printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
132
133	printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
134	       rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
135	       rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
136	printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
137	       rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
138	       rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
139}
140
141/*
142 * The show_stack() is external API which we do not use ourselves.
143 * The oops is printed in die_if_kernel.
144 */
145void show_stack(struct task_struct *tsk, unsigned long *_ksp, const char *loglvl)
146{
147	unsigned long pc, fp;
148	unsigned long task_base;
149	struct reg_window32 *rw;
150	int count = 0;
151
152	if (!tsk)
153		tsk = current;
154
155	if (tsk == current && !_ksp)
156		__asm__ __volatile__("mov	%%fp, %0" : "=r" (_ksp));
157
158	task_base = (unsigned long) task_stack_page(tsk);
159	fp = (unsigned long) _ksp;
160	do {
161		/* Bogus frame pointer? */
162		if (fp < (task_base + sizeof(struct thread_info)) ||
163		    fp >= (task_base + (PAGE_SIZE << 1)))
164			break;
165		rw = (struct reg_window32 *) fp;
166		pc = rw->ins[7];
167		printk("%s[%08lx : ", loglvl, pc);
168		printk("%s%pS ] ", loglvl, (void *) pc);
169		fp = rw->ins[6];
170	} while (++count < 16);
171	printk("%s\n", loglvl);
172}
173
174/*
175 * Free current thread data structures etc..
176 */
177void exit_thread(struct task_struct *tsk)
178{
179#ifndef CONFIG_SMP
180	if (last_task_used_math == tsk) {
181#else
182	if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {
183#endif
184		/* Keep process from leaving FPU in a bogon state. */
185		put_psr(get_psr() | PSR_EF);
186		fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
187		       &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
188#ifndef CONFIG_SMP
189		last_task_used_math = NULL;
190#else
191		clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
192#endif
193	}
194}
195
196void flush_thread(void)
197{
198	current_thread_info()->w_saved = 0;
199
200#ifndef CONFIG_SMP
201	if(last_task_used_math == current) {
202#else
203	if (test_thread_flag(TIF_USEDFPU)) {
204#endif
205		/* Clean the fpu. */
206		put_psr(get_psr() | PSR_EF);
207		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
208		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
209#ifndef CONFIG_SMP
210		last_task_used_math = NULL;
211#else
212		clear_thread_flag(TIF_USEDFPU);
213#endif
214	}
215}
216
217static inline struct sparc_stackf __user *
218clone_stackframe(struct sparc_stackf __user *dst,
219		 struct sparc_stackf __user *src)
220{
221	unsigned long size, fp;
222	struct sparc_stackf *tmp;
223	struct sparc_stackf __user *sp;
224
225	if (get_user(tmp, &src->fp))
226		return NULL;
227
228	fp = (unsigned long) tmp;
229	size = (fp - ((unsigned long) src));
230	fp = (unsigned long) dst;
231	sp = (struct sparc_stackf __user *)(fp - size);
232
233	/* do_fork() grabs the parent semaphore, we must release it
234	 * temporarily so we can build the child clone stack frame
235	 * without deadlocking.
236	 */
237	if (__copy_user(sp, src, size))
238		sp = NULL;
239	else if (put_user(fp, &sp->fp))
240		sp = NULL;
241
242	return sp;
243}
244
245/* Copy a Sparc thread.  The fork() return value conventions
246 * under SunOS are nothing short of bletcherous:
247 * Parent -->  %o0 == childs  pid, %o1 == 0
248 * Child  -->  %o0 == parents pid, %o1 == 1
249 *
250 * NOTE: We have a separate fork kpsr/kwim because
251 *       the parent could change these values between
252 *       sys_fork invocation and when we reach here
253 *       if the parent should sleep while trying to
254 *       allocate the task_struct and kernel stack in
255 *       do_fork().
256 * XXX See comment above sys_vfork in sparc64. todo.
257 */
258extern void ret_from_fork(void);
259extern void ret_from_kernel_thread(void);
260
261int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
262{
263	unsigned long clone_flags = args->flags;
264	unsigned long sp = args->stack;
265	unsigned long tls = args->tls;
266	struct thread_info *ti = task_thread_info(p);
267	struct pt_regs *childregs, *regs = current_pt_regs();
268	char *new_stack;
269
270#ifndef CONFIG_SMP
271	if(last_task_used_math == current) {
272#else
273	if (test_thread_flag(TIF_USEDFPU)) {
274#endif
275		put_psr(get_psr() | PSR_EF);
276		fpsave(&p->thread.float_regs[0], &p->thread.fsr,
277		       &p->thread.fpqueue[0], &p->thread.fpqdepth);
278	}
279
280	/*
281	 *  p->thread_info         new_stack   childregs stack bottom
282	 *  !                      !           !             !
283	 *  V                      V (stk.fr.) V  (pt_regs)  V
284	 *  +----- - - - - - ------+===========+=============+
285	 */
286	new_stack = task_stack_page(p) + THREAD_SIZE;
287	new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
288	childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
289
290	/*
291	 * A new process must start with interrupts disabled, see schedule_tail()
292	 * and finish_task_switch(). (If we do not do it and if a timer interrupt
293	 * hits before we unlock and attempts to take the rq->lock, we deadlock.)
294	 *
295	 * Thus, kpsr |= PSR_PIL.
296	 */
297	ti->ksp = (unsigned long) new_stack;
298	p->thread.kregs = childregs;
299
300	if (unlikely(args->fn)) {
301		extern int nwindows;
302		unsigned long psr;
303		memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
304		ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
305		childregs->u_regs[UREG_G1] = (unsigned long) args->fn;
306		childregs->u_regs[UREG_G2] = (unsigned long) args->fn_arg;
307		psr = childregs->psr = get_psr();
308		ti->kpsr = psr | PSR_PIL;
309		ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
310		return 0;
311	}
312	memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
313	childregs->u_regs[UREG_FP] = sp;
314	ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
315	ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
316	ti->kwim = current->thread.fork_kwim;
317
318	if (sp != regs->u_regs[UREG_FP]) {
319		struct sparc_stackf __user *childstack;
320		struct sparc_stackf __user *parentstack;
321
322		/*
323		 * This is a clone() call with supplied user stack.
324		 * Set some valid stack frames to give to the child.
325		 */
326		childstack = (struct sparc_stackf __user *)
327			(sp & ~0xfUL);
328		parentstack = (struct sparc_stackf __user *)
329			regs->u_regs[UREG_FP];
330
331#if 0
332		printk("clone: parent stack:\n");
333		show_stackframe(parentstack);
334#endif
335
336		childstack = clone_stackframe(childstack, parentstack);
337		if (!childstack)
338			return -EFAULT;
339
340#if 0
341		printk("clone: child stack:\n");
342		show_stackframe(childstack);
343#endif
344
345		childregs->u_regs[UREG_FP] = (unsigned long)childstack;
346	}
347
348#ifdef CONFIG_SMP
349	/* FPU must be disabled on SMP. */
350	childregs->psr &= ~PSR_EF;
351	clear_tsk_thread_flag(p, TIF_USEDFPU);
352#endif
353
354	/* Set the return value for the child. */
355	childregs->u_regs[UREG_I0] = current->pid;
356	childregs->u_regs[UREG_I1] = 1;
357
358	/* Set the return value for the parent. */
359	regs->u_regs[UREG_I1] = 0;
360
361	if (clone_flags & CLONE_SETTLS)
362		childregs->u_regs[UREG_G7] = tls;
363
364	return 0;
365}
366
367unsigned long __get_wchan(struct task_struct *task)
368{
369	unsigned long pc, fp, bias = 0;
370	unsigned long task_base = (unsigned long) task;
371        unsigned long ret = 0;
372	struct reg_window32 *rw;
373	int count = 0;
374
375	fp = task_thread_info(task)->ksp + bias;
376	do {
377		/* Bogus frame pointer? */
378		if (fp < (task_base + sizeof(struct thread_info)) ||
379		    fp >= (task_base + (2 * PAGE_SIZE)))
380			break;
381		rw = (struct reg_window32 *) fp;
382		pc = rw->ins[7];
383		if (!in_sched_functions(pc)) {
384			ret = pc;
385			goto out;
386		}
387		fp = rw->ins[6] + bias;
388	} while (++count < 16);
389
390out:
391	return ret;
392}
393
394