avr32: Call tick_nohz_{stop,restart}_sched_tick() in idle loop
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / avr32 / kernel / process.c
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1/*
2 * Copyright (C) 2004-2006 Atmel Corporation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8#include <linux/sched.h>
9#include <linux/module.h>
10#include <linux/kallsyms.h>
11#include <linux/fs.h>
12#include <linux/ptrace.h>
13#include <linux/reboot.h>
d45ad062 14#include <linux/tick.h>
623b0355 15#include <linux/uaccess.h>
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16#include <linux/unistd.h>
17
18#include <asm/sysreg.h>
19#include <asm/ocd.h>
20
21void (*pm_power_off)(void) = NULL;
22EXPORT_SYMBOL(pm_power_off);
23
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24extern void cpu_idle_sleep(void);
25
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26/*
27 * This file handles the architecture-dependent parts of process handling..
28 */
29
30void cpu_idle(void)
31{
32 /* endless idle loop with no priority at all */
33 while (1) {
d45ad062 34 tick_nohz_stop_sched_tick();
5f97f7f9 35 while (!need_resched())
19b7ce8b 36 cpu_idle_sleep();
d45ad062 37 tick_nohz_restart_sched_tick();
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38 preempt_enable_no_resched();
39 schedule();
40 preempt_disable();
41 }
42}
43
44void machine_halt(void)
45{
c2eb5090
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46 /*
47 * Enter Stop mode. The 32 kHz oscillator will keep running so
48 * the RTC will keep the time properly and the system will
49 * boot quickly.
50 */
51 asm volatile("sleep 3\n\t"
52 "sub pc, -2");
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53}
54
55void machine_power_off(void)
56{
57}
58
59void machine_restart(char *cmd)
60{
8dfe8f29
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61 ocd_write(DC, (1 << OCD_DC_DBE_BIT));
62 ocd_write(DC, (1 << OCD_DC_RES_BIT));
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63 while (1) ;
64}
65
66/*
67 * PC is actually discarded when returning from a system call -- the
68 * return address must be stored in LR. This function will make sure
69 * LR points to do_exit before starting the thread.
70 *
71 * Also, when returning from fork(), r12 is 0, so we must copy the
72 * argument as well.
73 *
74 * r0 : The argument to the main thread function
75 * r1 : The address of do_exit
76 * r2 : The address of the main thread function
77 */
78asmlinkage extern void kernel_thread_helper(void);
79__asm__(" .type kernel_thread_helper, @function\n"
80 "kernel_thread_helper:\n"
81 " mov r12, r0\n"
82 " mov lr, r2\n"
83 " mov pc, r1\n"
84 " .size kernel_thread_helper, . - kernel_thread_helper");
85
86int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
87{
88 struct pt_regs regs;
89
90 memset(&regs, 0, sizeof(regs));
91
92 regs.r0 = (unsigned long)arg;
93 regs.r1 = (unsigned long)fn;
94 regs.r2 = (unsigned long)do_exit;
95 regs.lr = (unsigned long)kernel_thread_helper;
96 regs.pc = (unsigned long)kernel_thread_helper;
97 regs.sr = MODE_SUPERVISOR;
98
99 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
100 0, &regs, 0, NULL, NULL);
101}
102EXPORT_SYMBOL(kernel_thread);
103
104/*
105 * Free current thread data structures etc
106 */
107void exit_thread(void)
108{
13b54a50 109 ocd_disable(current);
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110}
111
112void flush_thread(void)
113{
114 /* nothing to do */
115}
116
117void release_thread(struct task_struct *dead_task)
118{
119 /* do nothing */
120}
121
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122static void dump_mem(const char *str, const char *log_lvl,
123 unsigned long bottom, unsigned long top)
124{
125 unsigned long p;
126 int i;
127
128 printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);
129
130 for (p = bottom & ~31; p < top; ) {
131 printk("%s%04lx: ", log_lvl, p & 0xffff);
132
133 for (i = 0; i < 8; i++, p += 4) {
134 unsigned int val;
135
136 if (p < bottom || p >= top)
137 printk(" ");
138 else {
139 if (__get_user(val, (unsigned int __user *)p)) {
140 printk("\n");
141 goto out;
142 }
143 printk("%08x ", val);
144 }
145 }
146 printk("\n");
147 }
148
149out:
150 return;
151}
152
153static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
154{
155 return (p > (unsigned long)tinfo)
156 && (p < (unsigned long)tinfo + THREAD_SIZE - 3);
157}
158
159#ifdef CONFIG_FRAME_POINTER
160static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
161 struct pt_regs *regs, const char *log_lvl)
162{
163 unsigned long lr, fp;
164 struct thread_info *tinfo;
165
166 if (regs)
167 fp = regs->r7;
168 else if (tsk == current)
169 asm("mov %0, r7" : "=r"(fp));
170 else
171 fp = tsk->thread.cpu_context.r7;
172
173 /*
174 * Walk the stack as long as the frame pointer (a) is within
175 * the kernel stack of the task, and (b) it doesn't move
176 * downwards.
177 */
178 tinfo = task_thread_info(tsk);
179 printk("%sCall trace:\n", log_lvl);
180 while (valid_stack_ptr(tinfo, fp)) {
181 unsigned long new_fp;
182
183 lr = *(unsigned long *)fp;
184#ifdef CONFIG_KALLSYMS
185 printk("%s [<%08lx>] ", log_lvl, lr);
186#else
187 printk(" [<%08lx>] ", lr);
188#endif
189 print_symbol("%s\n", lr);
190
191 new_fp = *(unsigned long *)(fp + 4);
192 if (new_fp <= fp)
193 break;
194 fp = new_fp;
195 }
196 printk("\n");
197}
198#else
199static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
200 struct pt_regs *regs, const char *log_lvl)
201{
202 unsigned long addr;
203
204 printk("%sCall trace:\n", log_lvl);
205
206 while (!kstack_end(sp)) {
207 addr = *sp++;
208 if (kernel_text_address(addr)) {
209#ifdef CONFIG_KALLSYMS
210 printk("%s [<%08lx>] ", log_lvl, addr);
211#else
212 printk(" [<%08lx>] ", addr);
213#endif
214 print_symbol("%s\n", addr);
215 }
216 }
217 printk("\n");
218}
219#endif
220
221void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
222 struct pt_regs *regs, const char *log_lvl)
223{
224 struct thread_info *tinfo;
225
226 if (sp == 0) {
227 if (tsk)
228 sp = tsk->thread.cpu_context.ksp;
229 else
230 sp = (unsigned long)&tinfo;
231 }
232 if (!tsk)
233 tsk = current;
234
235 tinfo = task_thread_info(tsk);
236
237 if (valid_stack_ptr(tinfo, sp)) {
238 dump_mem("Stack: ", log_lvl, sp,
239 THREAD_SIZE + (unsigned long)tinfo);
240 show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
241 }
242}
243
244void show_stack(struct task_struct *tsk, unsigned long *stack)
245{
246 show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
247}
248
249void dump_stack(void)
250{
251 unsigned long stack;
252
253 show_trace_log_lvl(current, &stack, NULL, "");
254}
255EXPORT_SYMBOL(dump_stack);
256
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257static const char *cpu_modes[] = {
258 "Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
259 "Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
260};
261
623b0355 262void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
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263{
264 unsigned long sp = regs->sp;
265 unsigned long lr = regs->lr;
266 unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
267
623b0355 268 if (!user_mode(regs)) {
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269 sp = (unsigned long)regs + FRAME_SIZE_FULL;
270
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271 printk("%s", log_lvl);
272 print_symbol("PC is at %s\n", instruction_pointer(regs));
273 printk("%s", log_lvl);
274 print_symbol("LR is at %s\n", lr);
275 }
276
277 printk("%spc : [<%08lx>] lr : [<%08lx>] %s\n"
278 "%ssp : %08lx r12: %08lx r11: %08lx\n",
279 log_lvl, instruction_pointer(regs), lr, print_tainted(),
280 log_lvl, sp, regs->r12, regs->r11);
281 printk("%sr10: %08lx r9 : %08lx r8 : %08lx\n",
282 log_lvl, regs->r10, regs->r9, regs->r8);
283 printk("%sr7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
284 log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
285 printk("%sr3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
286 log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
287 printk("%sFlags: %c%c%c%c%c\n", log_lvl,
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288 regs->sr & SR_Q ? 'Q' : 'q',
289 regs->sr & SR_V ? 'V' : 'v',
290 regs->sr & SR_N ? 'N' : 'n',
291 regs->sr & SR_Z ? 'Z' : 'z',
292 regs->sr & SR_C ? 'C' : 'c');
df679771 293 printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
5f97f7f9 294 regs->sr & SR_H ? 'H' : 'h',
5f97f7f9 295 regs->sr & SR_J ? 'J' : 'j',
df679771
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296 regs->sr & SR_DM ? 'M' : 'm',
297 regs->sr & SR_D ? 'D' : 'd',
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298 regs->sr & SR_EM ? 'E' : 'e',
299 regs->sr & SR_I3M ? '3' : '.',
300 regs->sr & SR_I2M ? '2' : '.',
301 regs->sr & SR_I1M ? '1' : '.',
302 regs->sr & SR_I0M ? '0' : '.',
303 regs->sr & SR_GM ? 'G' : 'g');
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304 printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
305 printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
306 log_lvl, current->comm, current->pid, current,
307 task_thread_info(current));
308}
309
310void show_regs(struct pt_regs *regs)
311{
312 unsigned long sp = regs->sp;
313
314 if (!user_mode(regs))
315 sp = (unsigned long)regs + FRAME_SIZE_FULL;
5f97f7f9 316
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317 show_regs_log_lvl(regs, "");
318 show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
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319}
320EXPORT_SYMBOL(show_regs);
321
322/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
323int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
324{
325 /* Not valid */
326 return 0;
327}
328
329asmlinkage void ret_from_fork(void);
330
331int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
332 unsigned long unused,
333 struct task_struct *p, struct pt_regs *regs)
334{
335 struct pt_regs *childregs;
336
c9f4f06d 337 childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
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338 *childregs = *regs;
339
340 if (user_mode(regs))
341 childregs->sp = usp;
342 else
c9f4f06d 343 childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
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344
345 childregs->r12 = 0; /* Set return value for child */
346
347 p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
348 p->thread.cpu_context.ksp = (unsigned long)childregs;
349 p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
350
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351 if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
352 ocd_enable(p);
353
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354 return 0;
355}
356
357/* r12-r8 are dummy parameters to force the compiler to use the stack */
358asmlinkage int sys_fork(struct pt_regs *regs)
359{
360 return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
361}
362
363asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
364 unsigned long parent_tidptr,
365 unsigned long child_tidptr, struct pt_regs *regs)
366{
367 if (!newsp)
368 newsp = regs->sp;
369 return do_fork(clone_flags, newsp, regs, 0,
370 (int __user *)parent_tidptr,
371 (int __user *)child_tidptr);
372}
373
374asmlinkage int sys_vfork(struct pt_regs *regs)
375{
376 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
377 0, NULL, NULL);
378}
379
380asmlinkage int sys_execve(char __user *ufilename, char __user *__user *uargv,
381 char __user *__user *uenvp, struct pt_regs *regs)
382{
383 int error;
384 char *filename;
385
386 filename = getname(ufilename);
387 error = PTR_ERR(filename);
388 if (IS_ERR(filename))
389 goto out;
390
391 error = do_execve(filename, uargv, uenvp, regs);
392 if (error == 0)
393 current->ptrace &= ~PT_DTRACE;
394 putname(filename);
395
396out:
397 return error;
398}
399
400
401/*
402 * This function is supposed to answer the question "who called
403 * schedule()?"
404 */
405unsigned long get_wchan(struct task_struct *p)
406{
407 unsigned long pc;
408 unsigned long stack_page;
409
410 if (!p || p == current || p->state == TASK_RUNNING)
411 return 0;
412
c9f4f06d 413 stack_page = (unsigned long)task_stack_page(p);
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414 BUG_ON(!stack_page);
415
416 /*
417 * The stored value of PC is either the address right after
418 * the call to __switch_to() or ret_from_fork.
419 */
420 pc = thread_saved_pc(p);
421 if (in_sched_functions(pc)) {
422#ifdef CONFIG_FRAME_POINTER
423 unsigned long fp = p->thread.cpu_context.r7;
424 BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
425 pc = *(unsigned long *)fp;
426#else
427 /*
428 * We depend on the frame size of schedule here, which
429 * is actually quite ugly. It might be possible to
430 * determine the frame size automatically at build
431 * time by doing this:
432 * - compile sched.c
433 * - disassemble the resulting sched.o
434 * - look for 'sub sp,??' shortly after '<schedule>:'
435 */
436 unsigned long sp = p->thread.cpu_context.ksp + 16;
437 BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
438 pc = *(unsigned long *)sp;
439#endif
440 }
441
442 return pc;
443}