[PATCH] sched: resched and cpu_idle rework
[linux-2.6.git] / arch / sh / kernel / process.c
1 /* $Id: process.c,v 1.28 2004/05/05 16:54:23 lethal Exp $
2  *
3  *  linux/arch/sh/kernel/process.c
4  *
5  *  Copyright (C) 1995  Linus Torvalds
6  *
7  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
8  */
9
10 /*
11  * This file handles the architecture-dependent parts of process handling..
12  */
13
14 #include <linux/module.h>
15 #include <linux/unistd.h>
16 #include <linux/mm.h>
17 #include <linux/elfcore.h>
18 #include <linux/slab.h>
19 #include <linux/a.out.h>
20 #include <linux/ptrace.h>
21 #include <linux/platform.h>
22 #include <linux/kallsyms.h>
23
24 #include <asm/io.h>
25 #include <asm/uaccess.h>
26 #include <asm/mmu_context.h>
27 #include <asm/elf.h>
28 #if defined(CONFIG_SH_HS7751RVOIP)
29 #include <asm/hs7751rvoip/hs7751rvoip.h>
30 #elif defined(CONFIG_SH_RTS7751R2D)
31 #include <asm/rts7751r2d/rts7751r2d.h>
32 #endif
33
34 static int hlt_counter=0;
35
36 int ubc_usercnt = 0;
37
38 #define HARD_IDLE_TIMEOUT (HZ / 3)
39
40 void disable_hlt(void)
41 {
42         hlt_counter++;
43 }
44
45 EXPORT_SYMBOL(disable_hlt);
46
47 void enable_hlt(void)
48 {
49         hlt_counter--;
50 }
51
52 EXPORT_SYMBOL(enable_hlt);
53
54 void cpu_idle(void)
55 {
56         /* endless idle loop with no priority at all */
57         while (1) {
58                 if (hlt_counter) {
59                         while (!need_resched())
60                                 cpu_relax();
61                 } else {
62                         while (!need_resched())
63                                 cpu_sleep();
64                 }
65
66                 preempt_enable_no_resched();
67                 schedule();
68                 preempt_disable();
69         }
70 }
71
72 void machine_restart(char * __unused)
73 {
74         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
75         asm volatile("ldc %0, sr\n\t"
76                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
77 }
78
79 void machine_halt(void)
80 {
81 #if defined(CONFIG_SH_HS7751RVOIP)
82         unsigned short value;
83
84         value = ctrl_inw(PA_OUTPORTR);
85         ctrl_outw((value & 0xffdf), PA_OUTPORTR);
86 #elif defined(CONFIG_SH_RTS7751R2D)
87         ctrl_outw(0x0001, PA_POWOFF);
88 #endif
89         while (1)
90                 cpu_sleep();
91 }
92
93 void machine_power_off(void)
94 {
95 #if defined(CONFIG_SH_HS7751RVOIP)
96         unsigned short value;
97
98         value = ctrl_inw(PA_OUTPORTR);
99         ctrl_outw((value & 0xffdf), PA_OUTPORTR);
100 #elif defined(CONFIG_SH_RTS7751R2D)
101         ctrl_outw(0x0001, PA_POWOFF);
102 #endif
103 }
104
105 void show_regs(struct pt_regs * regs)
106 {
107         printk("\n");
108         printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
109         print_symbol("PC is at %s\n", regs->pc);
110         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
111                regs->pc, regs->regs[15], regs->sr);
112 #ifdef CONFIG_MMU
113         printk("TEA : %08x    ", ctrl_inl(MMU_TEA));
114 #else
115         printk("                  ");
116 #endif
117         printk("%s\n", print_tainted());
118
119         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
120                regs->regs[0],regs->regs[1],
121                regs->regs[2],regs->regs[3]);
122         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
123                regs->regs[4],regs->regs[5],
124                regs->regs[6],regs->regs[7]);
125         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
126                regs->regs[8],regs->regs[9],
127                regs->regs[10],regs->regs[11]);
128         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
129                regs->regs[12],regs->regs[13],
130                regs->regs[14]);
131         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
132                regs->mach, regs->macl, regs->gbr, regs->pr);
133
134         /*
135          * If we're in kernel mode, dump the stack too..
136          */
137         if (!user_mode(regs)) {
138                 extern void show_task(unsigned long *sp);
139                 unsigned long sp = regs->regs[15];
140
141                 show_task((unsigned long *)sp);
142         }
143 }
144
145 /*
146  * Create a kernel thread
147  */
148
149 /*
150  * This is the mechanism for creating a new kernel thread.
151  *
152  */
153 extern void kernel_thread_helper(void);
154 __asm__(".align 5\n"
155         "kernel_thread_helper:\n\t"
156         "jsr    @r5\n\t"
157         " nop\n\t"
158         "mov.l  1f, r1\n\t"
159         "jsr    @r1\n\t"
160         " mov   r0, r4\n\t"
161         ".align 2\n\t"
162         "1:.long do_exit");
163
164 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
165 {       /* Don't use this in BL=1(cli).  Or else, CPU resets! */
166         struct pt_regs regs;
167
168         memset(&regs, 0, sizeof(regs));
169         regs.regs[4] = (unsigned long) arg;
170         regs.regs[5] = (unsigned long) fn;
171
172         regs.pc = (unsigned long) kernel_thread_helper;
173         regs.sr = (1 << 30);
174
175         /* Ok, create the new process.. */
176         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
177 }
178
179 /*
180  * Free current thread data structures etc..
181  */
182 void exit_thread(void)
183 {
184         if (current->thread.ubc_pc) {
185                 current->thread.ubc_pc = 0;
186                 ubc_usercnt -= 1;
187         }
188 }
189
190 void flush_thread(void)
191 {
192 #if defined(CONFIG_SH_FPU)
193         struct task_struct *tsk = current;
194         struct pt_regs *regs = (struct pt_regs *)
195                                 ((unsigned long)tsk->thread_info
196                                  + THREAD_SIZE - sizeof(struct pt_regs)
197                                  - sizeof(unsigned long));
198
199         /* Forget lazy FPU state */
200         clear_fpu(tsk, regs);
201         clear_used_math();
202 #endif
203 }
204
205 void release_thread(struct task_struct *dead_task)
206 {
207         /* do nothing */
208 }
209
210 /* Fill in the fpu structure for a core dump.. */
211 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
212 {
213         int fpvalid = 0;
214
215 #if defined(CONFIG_SH_FPU)
216         struct task_struct *tsk = current;
217
218         fpvalid = !!tsk_used_math(tsk);
219         if (fpvalid) {
220                 unlazy_fpu(tsk, regs);
221                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
222         }
223 #endif
224
225         return fpvalid;
226 }
227
228 /* 
229  * Capture the user space registers if the task is not running (in user space)
230  */
231 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
232 {
233         struct pt_regs ptregs;
234         
235         ptregs = *(struct pt_regs *)
236                 ((unsigned long)tsk->thread_info + THREAD_SIZE
237                  - sizeof(struct pt_regs)
238 #ifdef CONFIG_SH_DSP
239                  - sizeof(struct pt_dspregs)
240 #endif
241                  - sizeof(unsigned long));
242         elf_core_copy_regs(regs, &ptregs);
243
244         return 1;
245 }
246
247 int
248 dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *fpu)
249 {
250         int fpvalid = 0;
251
252 #if defined(CONFIG_SH_FPU)
253         fpvalid = !!tsk_used_math(tsk);
254         if (fpvalid) {
255                 struct pt_regs *regs = (struct pt_regs *)
256                                         ((unsigned long)tsk->thread_info
257                                          + THREAD_SIZE - sizeof(struct pt_regs)
258                                          - sizeof(unsigned long));
259                 unlazy_fpu(tsk, regs);
260                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
261         }
262 #endif
263
264         return fpvalid;
265 }
266
267 asmlinkage void ret_from_fork(void);
268
269 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
270                 unsigned long unused,
271                 struct task_struct *p, struct pt_regs *regs)
272 {
273         struct pt_regs *childregs;
274 #if defined(CONFIG_SH_FPU)
275         struct task_struct *tsk = current;
276
277         unlazy_fpu(tsk, regs);
278         p->thread.fpu = tsk->thread.fpu;
279         copy_to_stopped_child_used_math(p);
280 #endif
281
282         childregs = ((struct pt_regs *)
283                 (THREAD_SIZE + (unsigned long) p->thread_info)
284 #ifdef CONFIG_SH_DSP
285                 - sizeof(struct pt_dspregs)
286 #endif
287                 - sizeof(unsigned long)) - 1;
288         *childregs = *regs;
289
290         if (user_mode(regs)) {
291                 childregs->regs[15] = usp;
292         } else {
293                 childregs->regs[15] = (unsigned long)p->thread_info + THREAD_SIZE;
294         }
295         if (clone_flags & CLONE_SETTLS) {
296                 childregs->gbr = childregs->regs[0];
297         }
298         childregs->regs[0] = 0; /* Set return value for child */
299
300         p->thread.sp = (unsigned long) childregs;
301         p->thread.pc = (unsigned long) ret_from_fork;
302
303         p->thread.ubc_pc = 0;
304
305         return 0;
306 }
307
308 /*
309  * fill in the user structure for a core dump..
310  */
311 void dump_thread(struct pt_regs * regs, struct user * dump)
312 {
313         dump->magic = CMAGIC;
314         dump->start_code = current->mm->start_code;
315         dump->start_data  = current->mm->start_data;
316         dump->start_stack = regs->regs[15] & ~(PAGE_SIZE - 1);
317         dump->u_tsize = (current->mm->end_code - dump->start_code) >> PAGE_SHIFT;
318         dump->u_dsize = (current->mm->brk + (PAGE_SIZE-1) - dump->start_data) >> PAGE_SHIFT;
319         dump->u_ssize = (current->mm->start_stack - dump->start_stack +
320                          PAGE_SIZE - 1) >> PAGE_SHIFT;
321         /* Debug registers will come here. */
322
323         dump->regs = *regs;
324
325         dump->u_fpvalid = dump_fpu(regs, &dump->fpu);
326 }
327
328 /* Tracing by user break controller.  */
329 static void
330 ubc_set_tracing(int asid, unsigned long pc)
331 {
332         ctrl_outl(pc, UBC_BARA);
333
334         /* We don't have any ASID settings for the SH-2! */
335         if (cpu_data->type != CPU_SH7604)
336                 ctrl_outb(asid, UBC_BASRA);
337
338         ctrl_outl(0, UBC_BAMRA);
339
340         if (cpu_data->type == CPU_SH7729) {
341                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
342                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
343         } else {
344                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
345                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
346         }
347 }
348
349 /*
350  *      switch_to(x,y) should switch tasks from x to y.
351  *
352  */
353 struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
354 {
355 #if defined(CONFIG_SH_FPU)
356         struct pt_regs *regs = (struct pt_regs *)
357                                 ((unsigned long)prev->thread_info
358                                  + THREAD_SIZE - sizeof(struct pt_regs)
359                                  - sizeof(unsigned long));
360         unlazy_fpu(prev, regs);
361 #endif
362
363 #ifdef CONFIG_PREEMPT
364         {
365                 unsigned long flags;
366                 struct pt_regs *regs;
367
368                 local_irq_save(flags);
369                 regs = (struct pt_regs *)
370                         ((unsigned long)prev->thread_info
371                          + THREAD_SIZE - sizeof(struct pt_regs)
372 #ifdef CONFIG_SH_DSP
373                          - sizeof(struct pt_dspregs)
374 #endif
375                          - sizeof(unsigned long));
376                 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
377                         int offset = (int)regs->regs[15];
378
379                         /* Reset stack pointer: clear critical region mark */
380                         regs->regs[15] = regs->regs[1];
381                         if (regs->pc < regs->regs[0])
382                                 /* Go to rewind point */
383                                 regs->pc = regs->regs[0] + offset;
384                 }
385                 local_irq_restore(flags);
386         }
387 #endif
388
389         /*
390          * Restore the kernel mode register
391          *      k7 (r7_bank1)
392          */
393         asm volatile("ldc       %0, r7_bank"
394                      : /* no output */
395                      : "r" (next->thread_info));
396
397 #ifdef CONFIG_MMU
398         /* If no tasks are using the UBC, we're done */
399         if (ubc_usercnt == 0)
400                 /* If no tasks are using the UBC, we're done */;
401         else if (next->thread.ubc_pc && next->mm) {
402                 ubc_set_tracing(next->mm->context & MMU_CONTEXT_ASID_MASK,
403                                 next->thread.ubc_pc);
404         } else {
405                 ctrl_outw(0, UBC_BBRA);
406                 ctrl_outw(0, UBC_BBRB);
407         }
408 #endif
409
410         return prev;
411 }
412
413 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
414                         unsigned long r6, unsigned long r7,
415                         struct pt_regs regs)
416 {
417 #ifdef CONFIG_MMU
418         return do_fork(SIGCHLD, regs.regs[15], &regs, 0, NULL, NULL);
419 #else
420         /* fork almost works, enough to trick you into looking elsewhere :-( */
421         return -EINVAL;
422 #endif
423 }
424
425 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
426                          unsigned long parent_tidptr,
427                          unsigned long child_tidptr,
428                          struct pt_regs regs)
429 {
430         if (!newsp)
431                 newsp = regs.regs[15];
432         return do_fork(clone_flags, newsp, &regs, 0,
433                         (int __user *)parent_tidptr, (int __user *)child_tidptr);
434 }
435
436 /*
437  * This is trivial, and on the face of it looks like it
438  * could equally well be done in user mode.
439  *
440  * Not so, for quite unobvious reasons - register pressure.
441  * In user mode vfork() cannot have a stack frame, and if
442  * done by calling the "clone()" system call directly, you
443  * do not have enough call-clobbered registers to hold all
444  * the information you need.
445  */
446 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
447                          unsigned long r6, unsigned long r7,
448                          struct pt_regs regs)
449 {
450         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.regs[15], &regs,
451                        0, NULL, NULL);
452 }
453
454 /*
455  * sys_execve() executes a new program.
456  */
457 asmlinkage int sys_execve(char *ufilename, char **uargv,
458                           char **uenvp, unsigned long r7,
459                           struct pt_regs regs)
460 {
461         int error;
462         char *filename;
463
464         filename = getname((char __user *)ufilename);
465         error = PTR_ERR(filename);
466         if (IS_ERR(filename))
467                 goto out;
468
469         error = do_execve(filename,
470                           (char __user * __user *)uargv,
471                           (char __user * __user *)uenvp,
472                           &regs);
473         if (error == 0) {
474                 task_lock(current);
475                 current->ptrace &= ~PT_DTRACE;
476                 task_unlock(current);
477         }
478         putname(filename);
479 out:
480         return error;
481 }
482
483 unsigned long get_wchan(struct task_struct *p)
484 {
485         unsigned long schedule_frame;
486         unsigned long pc;
487
488         if (!p || p == current || p->state == TASK_RUNNING)
489                 return 0;
490
491         /*
492          * The same comment as on the Alpha applies here, too ...
493          */
494         pc = thread_saved_pc(p);
495         if (in_sched_functions(pc)) {
496                 schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
497                 return (unsigned long)((unsigned long *)schedule_frame)[1];
498         }
499         return pc;
500 }
501
502 asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
503                                  unsigned long r6, unsigned long r7,
504                                  struct pt_regs regs)
505 {
506         /* Clear tracing.  */
507         ctrl_outw(0, UBC_BBRA);
508         ctrl_outw(0, UBC_BBRB);
509         current->thread.ubc_pc = 0;
510         ubc_usercnt -= 1;
511
512         force_sig(SIGTRAP, current);
513 }
514
515 asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
516                                           unsigned long r6, unsigned long r7,
517                                           struct pt_regs regs)
518 {
519         regs.pc -= 2;
520         force_sig(SIGTRAP, current);
521 }