xref: /openbmc/linux/arch/sh/kernel/process_32.c (revision 9ac8d3fb)
1 /*
2  * arch/sh/kernel/process.c
3  *
4  * This file handles the architecture-dependent parts of process handling..
5  *
6  *  Copyright (C) 1995  Linus Torvalds
7  *
8  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
9  *		     Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
10  *		     Copyright (C) 2002 - 2008  Paul Mundt
11  *
12  * This file is subject to the terms and conditions of the GNU General Public
13  * License.  See the file "COPYING" in the main directory of this archive
14  * for more details.
15  */
16 #include <linux/module.h>
17 #include <linux/mm.h>
18 #include <linux/elfcore.h>
19 #include <linux/pm.h>
20 #include <linux/kallsyms.h>
21 #include <linux/kexec.h>
22 #include <linux/kdebug.h>
23 #include <linux/tick.h>
24 #include <linux/reboot.h>
25 #include <linux/fs.h>
26 #include <linux/preempt.h>
27 #include <asm/uaccess.h>
28 #include <asm/mmu_context.h>
29 #include <asm/pgalloc.h>
30 #include <asm/system.h>
31 #include <asm/ubc.h>
32 #include <asm/fpu.h>
33 #include <asm/syscalls.h>
34 
35 static int hlt_counter;
36 int ubc_usercnt = 0;
37 
38 void (*pm_idle)(void);
39 void (*pm_power_off)(void);
40 EXPORT_SYMBOL(pm_power_off);
41 
42 static int __init nohlt_setup(char *__unused)
43 {
44 	hlt_counter = 1;
45 	return 1;
46 }
47 __setup("nohlt", nohlt_setup);
48 
49 static int __init hlt_setup(char *__unused)
50 {
51 	hlt_counter = 0;
52 	return 1;
53 }
54 __setup("hlt", hlt_setup);
55 
56 static void default_idle(void)
57 {
58 	if (!hlt_counter) {
59 		clear_thread_flag(TIF_POLLING_NRFLAG);
60 		smp_mb__after_clear_bit();
61 		set_bl_bit();
62 		while (!need_resched())
63 			cpu_sleep();
64 		clear_bl_bit();
65 		set_thread_flag(TIF_POLLING_NRFLAG);
66 	} else
67 		while (!need_resched())
68 			cpu_relax();
69 }
70 
71 void cpu_idle(void)
72 {
73 	set_thread_flag(TIF_POLLING_NRFLAG);
74 
75 	/* endless idle loop with no priority at all */
76 	while (1) {
77 		void (*idle)(void) = pm_idle;
78 
79 		if (!idle)
80 			idle = default_idle;
81 
82 		tick_nohz_stop_sched_tick(1);
83 		while (!need_resched())
84 			idle();
85 		tick_nohz_restart_sched_tick();
86 
87 		preempt_enable_no_resched();
88 		schedule();
89 		preempt_disable();
90 		check_pgt_cache();
91 	}
92 }
93 
94 void machine_restart(char * __unused)
95 {
96 	/* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
97 	asm volatile("ldc %0, sr\n\t"
98 		     "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
99 }
100 
101 void machine_halt(void)
102 {
103 	local_irq_disable();
104 
105 	while (1)
106 		cpu_sleep();
107 }
108 
109 void machine_power_off(void)
110 {
111 	if (pm_power_off)
112 		pm_power_off();
113 }
114 
115 void show_regs(struct pt_regs * regs)
116 {
117 	printk("\n");
118 	printk("Pid : %d, Comm: %20s\n", task_pid_nr(current), current->comm);
119 	printk("CPU : %d    %s  (%s %.*s)\n",
120 	       smp_processor_id(), print_tainted(), init_utsname()->release,
121 	       (int)strcspn(init_utsname()->version, " "),
122 	       init_utsname()->version);
123 
124 	print_symbol("PC is at %s\n", instruction_pointer(regs));
125 	print_symbol("PR is at %s\n", regs->pr);
126 
127 	printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
128 	       regs->pc, regs->regs[15], regs->sr);
129 #ifdef CONFIG_MMU
130 	printk("TEA : %08x\n", ctrl_inl(MMU_TEA));
131 #else
132 	printk("\n");
133 #endif
134 
135 	printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
136 	       regs->regs[0],regs->regs[1],
137 	       regs->regs[2],regs->regs[3]);
138 	printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
139 	       regs->regs[4],regs->regs[5],
140 	       regs->regs[6],regs->regs[7]);
141 	printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
142 	       regs->regs[8],regs->regs[9],
143 	       regs->regs[10],regs->regs[11]);
144 	printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
145 	       regs->regs[12],regs->regs[13],
146 	       regs->regs[14]);
147 	printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
148 	       regs->mach, regs->macl, regs->gbr, regs->pr);
149 
150 	show_trace(NULL, (unsigned long *)regs->regs[15], regs);
151 }
152 
153 /*
154  * Create a kernel thread
155  */
156 
157 /*
158  * This is the mechanism for creating a new kernel thread.
159  *
160  */
161 extern void kernel_thread_helper(void);
162 __asm__(".align 5\n"
163 	"kernel_thread_helper:\n\t"
164 	"jsr	@r5\n\t"
165 	" nop\n\t"
166 	"mov.l	1f, r1\n\t"
167 	"jsr	@r1\n\t"
168 	" mov	r0, r4\n\t"
169 	".align 2\n\t"
170 	"1:.long do_exit");
171 
172 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
173 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
174 {
175 	struct pt_regs regs;
176 	int pid;
177 
178 	memset(&regs, 0, sizeof(regs));
179 	regs.regs[4] = (unsigned long)arg;
180 	regs.regs[5] = (unsigned long)fn;
181 
182 	regs.pc = (unsigned long)kernel_thread_helper;
183 	regs.sr = (1 << 30);
184 
185 	/* Ok, create the new process.. */
186 	pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
187 		      &regs, 0, NULL, NULL);
188 
189 	trace_mark(kernel_arch_kthread_create, "pid %d fn %p", pid, fn);
190 
191 	return pid;
192 }
193 
194 /*
195  * Free current thread data structures etc..
196  */
197 void exit_thread(void)
198 {
199 	if (current->thread.ubc_pc) {
200 		current->thread.ubc_pc = 0;
201 		ubc_usercnt -= 1;
202 	}
203 }
204 
205 void flush_thread(void)
206 {
207 #if defined(CONFIG_SH_FPU)
208 	struct task_struct *tsk = current;
209 	/* Forget lazy FPU state */
210 	clear_fpu(tsk, task_pt_regs(tsk));
211 	clear_used_math();
212 #endif
213 }
214 
215 void release_thread(struct task_struct *dead_task)
216 {
217 	/* do nothing */
218 }
219 
220 /* Fill in the fpu structure for a core dump.. */
221 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
222 {
223 	int fpvalid = 0;
224 
225 #if defined(CONFIG_SH_FPU)
226 	struct task_struct *tsk = current;
227 
228 	fpvalid = !!tsk_used_math(tsk);
229 	if (fpvalid)
230 		fpvalid = !fpregs_get(tsk, NULL, 0,
231 				      sizeof(struct user_fpu_struct),
232 				      fpu, NULL);
233 #endif
234 
235 	return fpvalid;
236 }
237 
238 asmlinkage void ret_from_fork(void);
239 
240 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
241 		unsigned long unused,
242 		struct task_struct *p, struct pt_regs *regs)
243 {
244 	struct thread_info *ti = task_thread_info(p);
245 	struct pt_regs *childregs;
246 #if defined(CONFIG_SH_FPU)
247 	struct task_struct *tsk = current;
248 
249 	unlazy_fpu(tsk, regs);
250 	p->thread.fpu = tsk->thread.fpu;
251 	copy_to_stopped_child_used_math(p);
252 #endif
253 
254 	childregs = task_pt_regs(p);
255 	*childregs = *regs;
256 
257 	if (user_mode(regs)) {
258 		childregs->regs[15] = usp;
259 		ti->addr_limit = USER_DS;
260 	} else {
261 		childregs->regs[15] = (unsigned long)childregs;
262 		ti->addr_limit = KERNEL_DS;
263 	}
264 
265 	if (clone_flags & CLONE_SETTLS)
266 		childregs->gbr = childregs->regs[0];
267 
268 	childregs->regs[0] = 0; /* Set return value for child */
269 
270 	p->thread.sp = (unsigned long) childregs;
271 	p->thread.pc = (unsigned long) ret_from_fork;
272 
273 	p->thread.ubc_pc = 0;
274 
275 	return 0;
276 }
277 
278 /* Tracing by user break controller.  */
279 static void ubc_set_tracing(int asid, unsigned long pc)
280 {
281 #if defined(CONFIG_CPU_SH4A)
282 	unsigned long val;
283 
284 	val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
285 	val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
286 
287 	ctrl_outl(val, UBC_CBR0);
288 	ctrl_outl(pc,  UBC_CAR0);
289 	ctrl_outl(0x0, UBC_CAMR0);
290 	ctrl_outl(0x0, UBC_CBCR);
291 
292 	val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
293 	ctrl_outl(val, UBC_CRR0);
294 
295 	/* Read UBC register that we wrote last, for checking update */
296 	val = ctrl_inl(UBC_CRR0);
297 
298 #else	/* CONFIG_CPU_SH4A */
299 	ctrl_outl(pc, UBC_BARA);
300 
301 #ifdef CONFIG_MMU
302 	ctrl_outb(asid, UBC_BASRA);
303 #endif
304 
305 	ctrl_outl(0, UBC_BAMRA);
306 
307 	if (current_cpu_data.type == CPU_SH7729 ||
308 	    current_cpu_data.type == CPU_SH7710 ||
309 	    current_cpu_data.type == CPU_SH7712) {
310 		ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
311 		ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
312 	} else {
313 		ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
314 		ctrl_outw(BRCR_PCBA, UBC_BRCR);
315 	}
316 #endif	/* CONFIG_CPU_SH4A */
317 }
318 
319 /*
320  *	switch_to(x,y) should switch tasks from x to y.
321  *
322  */
323 struct task_struct *__switch_to(struct task_struct *prev,
324 				struct task_struct *next)
325 {
326 #if defined(CONFIG_SH_FPU)
327 	unlazy_fpu(prev, task_pt_regs(prev));
328 #endif
329 
330 #ifdef CONFIG_MMU
331 	/*
332 	 * Restore the kernel mode register
333 	 *	k7 (r7_bank1)
334 	 */
335 	asm volatile("ldc	%0, r7_bank"
336 		     : /* no output */
337 		     : "r" (task_thread_info(next)));
338 #endif
339 
340 	/* If no tasks are using the UBC, we're done */
341 	if (ubc_usercnt == 0)
342 		/* If no tasks are using the UBC, we're done */;
343 	else if (next->thread.ubc_pc && next->mm) {
344 		int asid = 0;
345 #ifdef CONFIG_MMU
346 		asid |= cpu_asid(smp_processor_id(), next->mm);
347 #endif
348 		ubc_set_tracing(asid, next->thread.ubc_pc);
349 	} else {
350 #if defined(CONFIG_CPU_SH4A)
351 		ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
352 		ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
353 #else
354 		ctrl_outw(0, UBC_BBRA);
355 		ctrl_outw(0, UBC_BBRB);
356 #endif
357 	}
358 
359 	return prev;
360 }
361 
362 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
363 			unsigned long r6, unsigned long r7,
364 			struct pt_regs __regs)
365 {
366 #ifdef CONFIG_MMU
367 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
368 	return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
369 #else
370 	/* fork almost works, enough to trick you into looking elsewhere :-( */
371 	return -EINVAL;
372 #endif
373 }
374 
375 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
376 			 unsigned long parent_tidptr,
377 			 unsigned long child_tidptr,
378 			 struct pt_regs __regs)
379 {
380 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
381 	if (!newsp)
382 		newsp = regs->regs[15];
383 	return do_fork(clone_flags, newsp, regs, 0,
384 			(int __user *)parent_tidptr,
385 			(int __user *)child_tidptr);
386 }
387 
388 /*
389  * This is trivial, and on the face of it looks like it
390  * could equally well be done in user mode.
391  *
392  * Not so, for quite unobvious reasons - register pressure.
393  * In user mode vfork() cannot have a stack frame, and if
394  * done by calling the "clone()" system call directly, you
395  * do not have enough call-clobbered registers to hold all
396  * the information you need.
397  */
398 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
399 			 unsigned long r6, unsigned long r7,
400 			 struct pt_regs __regs)
401 {
402 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
403 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
404 		       0, NULL, NULL);
405 }
406 
407 /*
408  * sys_execve() executes a new program.
409  */
410 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
411 			  char __user * __user *uenvp, unsigned long r7,
412 			  struct pt_regs __regs)
413 {
414 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
415 	int error;
416 	char *filename;
417 
418 	filename = getname(ufilename);
419 	error = PTR_ERR(filename);
420 	if (IS_ERR(filename))
421 		goto out;
422 
423 	error = do_execve(filename, uargv, uenvp, regs);
424 	if (error == 0) {
425 		task_lock(current);
426 		current->ptrace &= ~PT_DTRACE;
427 		task_unlock(current);
428 	}
429 	putname(filename);
430 out:
431 	return error;
432 }
433 
434 unsigned long get_wchan(struct task_struct *p)
435 {
436 	unsigned long pc;
437 
438 	if (!p || p == current || p->state == TASK_RUNNING)
439 		return 0;
440 
441 	/*
442 	 * The same comment as on the Alpha applies here, too ...
443 	 */
444 	pc = thread_saved_pc(p);
445 
446 #ifdef CONFIG_FRAME_POINTER
447 	if (in_sched_functions(pc)) {
448 		unsigned long schedule_frame = (unsigned long)p->thread.sp;
449 		return ((unsigned long *)schedule_frame)[21];
450 	}
451 #endif
452 
453 	return pc;
454 }
455 
456 asmlinkage void break_point_trap(void)
457 {
458 	/* Clear tracing.  */
459 #if defined(CONFIG_CPU_SH4A)
460 	ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
461 	ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
462 #else
463 	ctrl_outw(0, UBC_BBRA);
464 	ctrl_outw(0, UBC_BBRB);
465 #endif
466 	current->thread.ubc_pc = 0;
467 	ubc_usercnt -= 1;
468 
469 	force_sig(SIGTRAP, current);
470 }
471