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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/pm.h>
13#include <linux/ptrace.h>
14#include <linux/slab.h>
15#include <linux/reboot.h>
16#include <linux/tick.h>
17#include <linux/uaccess.h>
18#include <linux/unistd.h>
19
20#include <asm/sysreg.h>
21#include <asm/ocd.h>
22#include <asm/syscalls.h>
23
24#include <mach/pm.h>
25
26void (*pm_power_off)(void);
27EXPORT_SYMBOL(pm_power_off);
28
29/*
30 * This file handles the architecture-dependent parts of process handling..
31 */
32
33void cpu_idle(void)
34{
35 /* endless idle loop with no priority at all */
36 while (1) {
37 tick_nohz_stop_sched_tick(1);
38 while (!need_resched())
39 cpu_idle_sleep();
40 tick_nohz_restart_sched_tick();
41 preempt_enable_no_resched();
42 schedule();
43 preempt_disable();
44 }
45}
46
47void machine_halt(void)
48{
49 /*
50 * Enter Stop mode. The 32 kHz oscillator will keep running so
51 * the RTC will keep the time properly and the system will
52 * boot quickly.
53 */
54 asm volatile("sleep 3\n\t"
55 "sub pc, -2");
56}
57
58void machine_power_off(void)
59{
60 if (pm_power_off)
61 pm_power_off();
62}
63
64void machine_restart(char *cmd)
65{
66 ocd_write(DC, (1 << OCD_DC_DBE_BIT));
67 ocd_write(DC, (1 << OCD_DC_RES_BIT));
68 while (1) ;
69}
70
71/*
72 * PC is actually discarded when returning from a system call -- the
73 * return address must be stored in LR. This function will make sure
74 * LR points to do_exit before starting the thread.
75 *
76 * Also, when returning from fork(), r12 is 0, so we must copy the
77 * argument as well.
78 *
79 * r0 : The argument to the main thread function
80 * r1 : The address of do_exit
81 * r2 : The address of the main thread function
82 */
83asmlinkage extern void kernel_thread_helper(void);
84__asm__(" .type kernel_thread_helper, @function\n"
85 "kernel_thread_helper:\n"
86 " mov r12, r0\n"
87 " mov lr, r2\n"
88 " mov pc, r1\n"
89 " .size kernel_thread_helper, . - kernel_thread_helper");
90
91int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
92{
93 struct pt_regs regs;
94
95 memset(®s, 0, sizeof(regs));
96
97 regs.r0 = (unsigned long)arg;
98 regs.r1 = (unsigned long)fn;
99 regs.r2 = (unsigned long)do_exit;
100 regs.lr = (unsigned long)kernel_thread_helper;
101 regs.pc = (unsigned long)kernel_thread_helper;
102 regs.sr = MODE_SUPERVISOR;
103
104 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
105 0, ®s, 0, NULL, NULL);
106}
107EXPORT_SYMBOL(kernel_thread);
108
109/*
110 * Free current thread data structures etc
111 */
112void exit_thread(void)
113{
114 ocd_disable(current);
115}
116
117void flush_thread(void)
118{
119 /* nothing to do */
120}
121
122void release_thread(struct task_struct *dead_task)
123{
124 /* do nothing */
125}
126
127static void dump_mem(const char *str, const char *log_lvl,
128 unsigned long bottom, unsigned long top)
129{
130 unsigned long p;
131 int i;
132
133 printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);
134
135 for (p = bottom & ~31; p < top; ) {
136 printk("%s%04lx: ", log_lvl, p & 0xffff);
137
138 for (i = 0; i < 8; i++, p += 4) {
139 unsigned int val;
140
141 if (p < bottom || p >= top)
142 printk(" ");
143 else {
144 if (__get_user(val, (unsigned int __user *)p)) {
145 printk("\n");
146 goto out;
147 }
148 printk("%08x ", val);
149 }
150 }
151 printk("\n");
152 }
153
154out:
155 return;
156}
157
158static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
159{
160 return (p > (unsigned long)tinfo)
161 && (p < (unsigned long)tinfo + THREAD_SIZE - 3);
162}
163
164#ifdef CONFIG_FRAME_POINTER
165static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
166 struct pt_regs *regs, const char *log_lvl)
167{
168 unsigned long lr, fp;
169 struct thread_info *tinfo;
170
171 if (regs)
172 fp = regs->r7;
173 else if (tsk == current)
174 asm("mov %0, r7" : "=r"(fp));
175 else
176 fp = tsk->thread.cpu_context.r7;
177
178 /*
179 * Walk the stack as long as the frame pointer (a) is within
180 * the kernel stack of the task, and (b) it doesn't move
181 * downwards.
182 */
183 tinfo = task_thread_info(tsk);
184 printk("%sCall trace:\n", log_lvl);
185 while (valid_stack_ptr(tinfo, fp)) {
186 unsigned long new_fp;
187
188 lr = *(unsigned long *)fp;
189#ifdef CONFIG_KALLSYMS
190 printk("%s [<%08lx>] ", log_lvl, lr);
191#else
192 printk(" [<%08lx>] ", lr);
193#endif
194 print_symbol("%s\n", lr);
195
196 new_fp = *(unsigned long *)(fp + 4);
197 if (new_fp <= fp)
198 break;
199 fp = new_fp;
200 }
201 printk("\n");
202}
203#else
204static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
205 struct pt_regs *regs, const char *log_lvl)
206{
207 unsigned long addr;
208
209 printk("%sCall trace:\n", log_lvl);
210
211 while (!kstack_end(sp)) {
212 addr = *sp++;
213 if (kernel_text_address(addr)) {
214#ifdef CONFIG_KALLSYMS
215 printk("%s [<%08lx>] ", log_lvl, addr);
216#else
217 printk(" [<%08lx>] ", addr);
218#endif
219 print_symbol("%s\n", addr);
220 }
221 }
222 printk("\n");
223}
224#endif
225
226void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
227 struct pt_regs *regs, const char *log_lvl)
228{
229 struct thread_info *tinfo;
230
231 if (sp == 0) {
232 if (tsk)
233 sp = tsk->thread.cpu_context.ksp;
234 else
235 sp = (unsigned long)&tinfo;
236 }
237 if (!tsk)
238 tsk = current;
239
240 tinfo = task_thread_info(tsk);
241
242 if (valid_stack_ptr(tinfo, sp)) {
243 dump_mem("Stack: ", log_lvl, sp,
244 THREAD_SIZE + (unsigned long)tinfo);
245 show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
246 }
247}
248
249void show_stack(struct task_struct *tsk, unsigned long *stack)
250{
251 show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
252}
253
254void dump_stack(void)
255{
256 unsigned long stack;
257
258 show_trace_log_lvl(current, &stack, NULL, "");
259}
260EXPORT_SYMBOL(dump_stack);
261
262static const char *cpu_modes[] = {
263 "Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
264 "Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
265};
266
267void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
268{
269 unsigned long sp = regs->sp;
270 unsigned long lr = regs->lr;
271 unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
272
273 if (!user_mode(regs)) {
274 sp = (unsigned long)regs + FRAME_SIZE_FULL;
275
276 printk("%s", log_lvl);
277 print_symbol("PC is at %s\n", instruction_pointer(regs));
278 printk("%s", log_lvl);
279 print_symbol("LR is at %s\n", lr);
280 }
281
282 printk("%spc : [<%08lx>] lr : [<%08lx>] %s\n"
283 "%ssp : %08lx r12: %08lx r11: %08lx\n",
284 log_lvl, instruction_pointer(regs), lr, print_tainted(),
285 log_lvl, sp, regs->r12, regs->r11);
286 printk("%sr10: %08lx r9 : %08lx r8 : %08lx\n",
287 log_lvl, regs->r10, regs->r9, regs->r8);
288 printk("%sr7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
289 log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
290 printk("%sr3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
291 log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
292 printk("%sFlags: %c%c%c%c%c\n", log_lvl,
293 regs->sr & SR_Q ? 'Q' : 'q',
294 regs->sr & SR_V ? 'V' : 'v',
295 regs->sr & SR_N ? 'N' : 'n',
296 regs->sr & SR_Z ? 'Z' : 'z',
297 regs->sr & SR_C ? 'C' : 'c');
298 printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
299 regs->sr & SR_H ? 'H' : 'h',
300 regs->sr & SR_J ? 'J' : 'j',
301 regs->sr & SR_DM ? 'M' : 'm',
302 regs->sr & SR_D ? 'D' : 'd',
303 regs->sr & SR_EM ? 'E' : 'e',
304 regs->sr & SR_I3M ? '3' : '.',
305 regs->sr & SR_I2M ? '2' : '.',
306 regs->sr & SR_I1M ? '1' : '.',
307 regs->sr & SR_I0M ? '0' : '.',
308 regs->sr & SR_GM ? 'G' : 'g');
309 printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
310 printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
311 log_lvl, current->comm, current->pid, current,
312 task_thread_info(current));
313}
314
315void show_regs(struct pt_regs *regs)
316{
317 unsigned long sp = regs->sp;
318
319 if (!user_mode(regs))
320 sp = (unsigned long)regs + FRAME_SIZE_FULL;
321
322 show_regs_log_lvl(regs, "");
323 show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
324}
325EXPORT_SYMBOL(show_regs);
326
327/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
328int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
329{
330 /* Not valid */
331 return 0;
332}
333
334asmlinkage void ret_from_fork(void);
335
336int copy_thread(unsigned long clone_flags, unsigned long usp,
337 unsigned long unused,
338 struct task_struct *p, struct pt_regs *regs)
339{
340 struct pt_regs *childregs;
341
342 childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
343 *childregs = *regs;
344
345 if (user_mode(regs))
346 childregs->sp = usp;
347 else
348 childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
349
350 childregs->r12 = 0; /* Set return value for child */
351
352 p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
353 p->thread.cpu_context.ksp = (unsigned long)childregs;
354 p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
355
356 clear_tsk_thread_flag(p, TIF_DEBUG);
357 if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
358 ocd_enable(p);
359
360 return 0;
361}
362
363/* r12-r8 are dummy parameters to force the compiler to use the stack */
364asmlinkage int sys_fork(struct pt_regs *regs)
365{
366 return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
367}
368
369asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
370 void __user *parent_tidptr, void __user *child_tidptr,
371 struct pt_regs *regs)
372{
373 if (!newsp)
374 newsp = regs->sp;
375 return do_fork(clone_flags, newsp, regs, 0, parent_tidptr,
376 child_tidptr);
377}
378
379asmlinkage int sys_vfork(struct pt_regs *regs)
380{
381 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
382 0, NULL, NULL);
383}
384
385asmlinkage int sys_execve(const char __user *ufilename,
386 const char __user *const __user *uargv,
387 const char __user *const __user *uenvp,
388 struct pt_regs *regs)
389{
390 int error;
391 char *filename;
392
393 filename = getname(ufilename);
394 error = PTR_ERR(filename);
395 if (IS_ERR(filename))
396 goto out;
397
398 error = do_execve(filename, uargv, uenvp, regs);
399 putname(filename);
400
401out:
402 return error;
403}
404
405
406/*
407 * This function is supposed to answer the question "who called
408 * schedule()?"
409 */
410unsigned long get_wchan(struct task_struct *p)
411{
412 unsigned long pc;
413 unsigned long stack_page;
414
415 if (!p || p == current || p->state == TASK_RUNNING)
416 return 0;
417
418 stack_page = (unsigned long)task_stack_page(p);
419 BUG_ON(!stack_page);
420
421 /*
422 * The stored value of PC is either the address right after
423 * the call to __switch_to() or ret_from_fork.
424 */
425 pc = thread_saved_pc(p);
426 if (in_sched_functions(pc)) {
427#ifdef CONFIG_FRAME_POINTER
428 unsigned long fp = p->thread.cpu_context.r7;
429 BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
430 pc = *(unsigned long *)fp;
431#else
432 /*
433 * We depend on the frame size of schedule here, which
434 * is actually quite ugly. It might be possible to
435 * determine the frame size automatically at build
436 * time by doing this:
437 * - compile sched.c
438 * - disassemble the resulting sched.o
439 * - look for 'sub sp,??' shortly after '<schedule>:'
440 */
441 unsigned long sp = p->thread.cpu_context.ksp + 16;
442 BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
443 pc = *(unsigned long *)sp;
444#endif
445 }
446
447 return pc;
448}