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 }
75
76 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
machine_halt(void)77 void machine_halt(void)
78 {
79 local_irq_enable();
80 mdelay(8);
81 local_irq_disable();
82 prom_halt();
83 panic("Halt failed!");
84 }
85
machine_restart(char * cmd)86 void 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
machine_power_off(void)104 void 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
show_regs(struct pt_regs * r)116 void 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 */
show_stack(struct task_struct * tsk,unsigned long * _ksp,const char * loglvl)145 void 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 */
exit_thread(struct task_struct * tsk)177 void 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
196 void 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(¤t->thread.float_regs[0], ¤t->thread.fsr,
208 ¤t->thread.fpqueue[0], ¤t->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
217 static inline struct sparc_stackf __user *
218 clone_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 */
258 extern void ret_from_fork(void);
259 extern void ret_from_kernel_thread(void);
260
261 int 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
367 unsigned 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
390 out:
391 return ret;
392 }
393
394