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