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
12 #include <stdarg.h>
13
14 #include <linux/elfcore.h>
15 #include <linux/errno.h>
16 #include <linux/module.h>
17 #include <linux/sched.h>
18 #include <linux/sched/debug.h>
19 #include <linux/sched/task.h>
20 #include <linux/sched/task_stack.h>
21 #include <linux/kernel.h>
22 #include <linux/mm.h>
23 #include <linux/stddef.h>
24 #include <linux/ptrace.h>
25 #include <linux/user.h>
26 #include <linux/smp.h>
27 #include <linux/reboot.h>
28 #include <linux/delay.h>
29 #include <linux/pm.h>
30 #include <linux/slab.h>
31 #include <linux/cpu.h>
32
33 #include <asm/auxio.h>
34 #include <asm/oplib.h>
35 #include <linux/uaccess.h>
36 #include <asm/page.h>
37 #include <asm/delay.h>
38 #include <asm/processor.h>
39 #include <asm/psr.h>
40 #include <asm/elf.h>
41 #include <asm/prom.h>
42 #include <asm/unistd.h>
43 #include <asm/setup.h>
44
45 #include "kernel.h"
46
47 /*
48 * Power management idle function
49 * Set in pm platform drivers (apc.c and pmc.c)
50 */
51 void (*sparc_idle)(void);
52
53 /*
54 * Power-off handler instantiation for pm.h compliance
55 * This is done via auxio, but could be used as a fallback
56 * handler when auxio is not present-- unused for now...
57 */
58 void (*pm_power_off)(void) = machine_power_off;
59 EXPORT_SYMBOL(pm_power_off);
60
61 /*
62 * sysctl - toggle power-off restriction for serial console
63 * systems in machine_power_off()
64 */
65 int scons_pwroff = 1;
66
67 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
68
69 struct task_struct *last_task_used_math = NULL;
70 struct thread_info *current_set[NR_CPUS];
71
72 /* Idle loop support. */
arch_cpu_idle(void)73 void arch_cpu_idle(void)
74 {
75 if (sparc_idle)
76 (*sparc_idle)();
77 raw_local_irq_enable();
78 }
79
80 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
machine_halt(void)81 void machine_halt(void)
82 {
83 local_irq_enable();
84 mdelay(8);
85 local_irq_disable();
86 prom_halt();
87 panic("Halt failed!");
88 }
89
machine_restart(char * cmd)90 void machine_restart(char * cmd)
91 {
92 char *p;
93
94 local_irq_enable();
95 mdelay(8);
96 local_irq_disable();
97
98 p = strchr (reboot_command, '\n');
99 if (p) *p = 0;
100 if (cmd)
101 prom_reboot(cmd);
102 if (*reboot_command)
103 prom_reboot(reboot_command);
104 prom_feval ("reset");
105 panic("Reboot failed!");
106 }
107
machine_power_off(void)108 void machine_power_off(void)
109 {
110 if (auxio_power_register &&
111 (!of_node_is_type(of_console_device, "serial") || scons_pwroff)) {
112 u8 power_register = sbus_readb(auxio_power_register);
113 power_register |= AUXIO_POWER_OFF;
114 sbus_writeb(power_register, auxio_power_register);
115 }
116
117 machine_halt();
118 }
119
show_regs(struct pt_regs * r)120 void show_regs(struct pt_regs *r)
121 {
122 struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
123
124 show_regs_print_info(KERN_DEFAULT);
125
126 printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx %s\n",
127 r->psr, r->pc, r->npc, r->y, print_tainted());
128 printk("PC: <%pS>\n", (void *) r->pc);
129 printk("%%G: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
130 r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
131 r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
132 printk("%%O: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
133 r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
134 r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
135 printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
136
137 printk("%%L: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
138 rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
139 rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
140 printk("%%I: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
141 rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
142 rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
143 }
144
145 /*
146 * The show_stack() is external API which we do not use ourselves.
147 * The oops is printed in die_if_kernel.
148 */
show_stack(struct task_struct * tsk,unsigned long * _ksp,const char * loglvl)149 void show_stack(struct task_struct *tsk, unsigned long *_ksp, const char *loglvl)
150 {
151 unsigned long pc, fp;
152 unsigned long task_base;
153 struct reg_window32 *rw;
154 int count = 0;
155
156 if (!tsk)
157 tsk = current;
158
159 if (tsk == current && !_ksp)
160 __asm__ __volatile__("mov %%fp, %0" : "=r" (_ksp));
161
162 task_base = (unsigned long) task_stack_page(tsk);
163 fp = (unsigned long) _ksp;
164 do {
165 /* Bogus frame pointer? */
166 if (fp < (task_base + sizeof(struct thread_info)) ||
167 fp >= (task_base + (PAGE_SIZE << 1)))
168 break;
169 rw = (struct reg_window32 *) fp;
170 pc = rw->ins[7];
171 printk("%s[%08lx : ", loglvl, pc);
172 printk("%s%pS ] ", loglvl, (void *) pc);
173 fp = rw->ins[6];
174 } while (++count < 16);
175 printk("%s\n", loglvl);
176 }
177
178 /*
179 * Free current thread data structures etc..
180 */
exit_thread(struct task_struct * tsk)181 void exit_thread(struct task_struct *tsk)
182 {
183 #ifndef CONFIG_SMP
184 if (last_task_used_math == tsk) {
185 #else
186 if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {
187 #endif
188 /* Keep process from leaving FPU in a bogon state. */
189 put_psr(get_psr() | PSR_EF);
190 fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
191 &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
192 #ifndef CONFIG_SMP
193 last_task_used_math = NULL;
194 #else
195 clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
196 #endif
197 }
198 }
199
200 void flush_thread(void)
201 {
202 current_thread_info()->w_saved = 0;
203
204 #ifndef CONFIG_SMP
205 if(last_task_used_math == current) {
206 #else
207 if (test_thread_flag(TIF_USEDFPU)) {
208 #endif
209 /* Clean the fpu. */
210 put_psr(get_psr() | PSR_EF);
211 fpsave(¤t->thread.float_regs[0], ¤t->thread.fsr,
212 ¤t->thread.fpqueue[0], ¤t->thread.fpqdepth);
213 #ifndef CONFIG_SMP
214 last_task_used_math = NULL;
215 #else
216 clear_thread_flag(TIF_USEDFPU);
217 #endif
218 }
219 }
220
221 static inline struct sparc_stackf __user *
222 clone_stackframe(struct sparc_stackf __user *dst,
223 struct sparc_stackf __user *src)
224 {
225 unsigned long size, fp;
226 struct sparc_stackf *tmp;
227 struct sparc_stackf __user *sp;
228
229 if (get_user(tmp, &src->fp))
230 return NULL;
231
232 fp = (unsigned long) tmp;
233 size = (fp - ((unsigned long) src));
234 fp = (unsigned long) dst;
235 sp = (struct sparc_stackf __user *)(fp - size);
236
237 /* do_fork() grabs the parent semaphore, we must release it
238 * temporarily so we can build the child clone stack frame
239 * without deadlocking.
240 */
241 if (__copy_user(sp, src, size))
242 sp = NULL;
243 else if (put_user(fp, &sp->fp))
244 sp = NULL;
245
246 return sp;
247 }
248
249 /* Copy a Sparc thread. The fork() return value conventions
250 * under SunOS are nothing short of bletcherous:
251 * Parent --> %o0 == childs pid, %o1 == 0
252 * Child --> %o0 == parents pid, %o1 == 1
253 *
254 * NOTE: We have a separate fork kpsr/kwim because
255 * the parent could change these values between
256 * sys_fork invocation and when we reach here
257 * if the parent should sleep while trying to
258 * allocate the task_struct and kernel stack in
259 * do_fork().
260 * XXX See comment above sys_vfork in sparc64. todo.
261 */
262 extern void ret_from_fork(void);
263 extern void ret_from_kernel_thread(void);
264
265 int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
266 struct task_struct *p, unsigned long tls)
267 {
268 struct thread_info *ti = task_thread_info(p);
269 struct pt_regs *childregs, *regs = current_pt_regs();
270 char *new_stack;
271
272 #ifndef CONFIG_SMP
273 if(last_task_used_math == current) {
274 #else
275 if (test_thread_flag(TIF_USEDFPU)) {
276 #endif
277 put_psr(get_psr() | PSR_EF);
278 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
279 &p->thread.fpqueue[0], &p->thread.fpqdepth);
280 }
281
282 /*
283 * p->thread_info new_stack childregs stack bottom
284 * ! ! ! !
285 * V V (stk.fr.) V (pt_regs) V
286 * +----- - - - - - ------+===========+=============+
287 */
288 new_stack = task_stack_page(p) + THREAD_SIZE;
289 new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
290 childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
291
292 /*
293 * A new process must start with interrupts disabled, see schedule_tail()
294 * and finish_task_switch(). (If we do not do it and if a timer interrupt
295 * hits before we unlock and attempts to take the rq->lock, we deadlock.)
296 *
297 * Thus, kpsr |= PSR_PIL.
298 */
299 ti->ksp = (unsigned long) new_stack;
300 p->thread.kregs = childregs;
301
302 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
303 extern int nwindows;
304 unsigned long psr;
305 memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
306 p->thread.current_ds = KERNEL_DS;
307 ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
308 childregs->u_regs[UREG_G1] = sp; /* function */
309 childregs->u_regs[UREG_G2] = arg;
310 psr = childregs->psr = get_psr();
311 ti->kpsr = psr | PSR_PIL;
312 ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
313 return 0;
314 }
315 memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
316 childregs->u_regs[UREG_FP] = sp;
317 p->thread.current_ds = USER_DS;
318 ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
319 ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
320 ti->kwim = current->thread.fork_kwim;
321
322 if (sp != regs->u_regs[UREG_FP]) {
323 struct sparc_stackf __user *childstack;
324 struct sparc_stackf __user *parentstack;
325
326 /*
327 * This is a clone() call with supplied user stack.
328 * Set some valid stack frames to give to the child.
329 */
330 childstack = (struct sparc_stackf __user *)
331 (sp & ~0xfUL);
332 parentstack = (struct sparc_stackf __user *)
333 regs->u_regs[UREG_FP];
334
335 #if 0
336 printk("clone: parent stack:\n");
337 show_stackframe(parentstack);
338 #endif
339
340 childstack = clone_stackframe(childstack, parentstack);
341 if (!childstack)
342 return -EFAULT;
343
344 #if 0
345 printk("clone: child stack:\n");
346 show_stackframe(childstack);
347 #endif
348
349 childregs->u_regs[UREG_FP] = (unsigned long)childstack;
350 }
351
352 #ifdef CONFIG_SMP
353 /* FPU must be disabled on SMP. */
354 childregs->psr &= ~PSR_EF;
355 clear_tsk_thread_flag(p, TIF_USEDFPU);
356 #endif
357
358 /* Set the return value for the child. */
359 childregs->u_regs[UREG_I0] = current->pid;
360 childregs->u_regs[UREG_I1] = 1;
361
362 /* Set the return value for the parent. */
363 regs->u_regs[UREG_I1] = 0;
364
365 if (clone_flags & CLONE_SETTLS)
366 childregs->u_regs[UREG_G7] = tls;
367
368 return 0;
369 }
370
371 unsigned long get_wchan(struct task_struct *task)
372 {
373 unsigned long pc, fp, bias = 0;
374 unsigned long task_base = (unsigned long) task;
375 unsigned long ret = 0;
376 struct reg_window32 *rw;
377 int count = 0;
378
379 if (!task || task == current ||
380 task->state == TASK_RUNNING)
381 goto out;
382
383 fp = task_thread_info(task)->ksp + bias;
384 do {
385 /* Bogus frame pointer? */
386 if (fp < (task_base + sizeof(struct thread_info)) ||
387 fp >= (task_base + (2 * PAGE_SIZE)))
388 break;
389 rw = (struct reg_window32 *) fp;
390 pc = rw->ins[7];
391 if (!in_sched_functions(pc)) {
392 ret = pc;
393 goto out;
394 }
395 fp = rw->ins[6] + bias;
396 } while (++count < 16);
397
398 out:
399 return ret;
400 }
401
402