[PATCH] arm: end_of_stack()
[linux-2.6.git] / arch / arm / kernel / process.c
1 /*
2  *  linux/arch/arm/kernel/process.c
3  *
4  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
5  *  Original Copyright (C) 1995  Linus Torvalds
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 #include <stdarg.h>
12
13 #include <linux/config.h>
14 #include <linux/module.h>
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/mm.h>
18 #include <linux/stddef.h>
19 #include <linux/unistd.h>
20 #include <linux/ptrace.h>
21 #include <linux/slab.h>
22 #include <linux/user.h>
23 #include <linux/a.out.h>
24 #include <linux/delay.h>
25 #include <linux/reboot.h>
26 #include <linux/interrupt.h>
27 #include <linux/kallsyms.h>
28 #include <linux/init.h>
29 #include <linux/cpu.h>
30
31 #include <asm/leds.h>
32 #include <asm/processor.h>
33 #include <asm/system.h>
34 #include <asm/uaccess.h>
35 #include <asm/mach/time.h>
36
37 extern const char *processor_modes[];
38 extern void setup_mm_for_reboot(char mode);
39
40 static volatile int hlt_counter;
41
42 #include <asm/arch/system.h>
43
44 void disable_hlt(void)
45 {
46         hlt_counter++;
47 }
48
49 EXPORT_SYMBOL(disable_hlt);
50
51 void enable_hlt(void)
52 {
53         hlt_counter--;
54 }
55
56 EXPORT_SYMBOL(enable_hlt);
57
58 static int __init nohlt_setup(char *__unused)
59 {
60         hlt_counter = 1;
61         return 1;
62 }
63
64 static int __init hlt_setup(char *__unused)
65 {
66         hlt_counter = 0;
67         return 1;
68 }
69
70 __setup("nohlt", nohlt_setup);
71 __setup("hlt", hlt_setup);
72
73 /*
74  * The following aren't currently used.
75  */
76 void (*pm_idle)(void);
77 EXPORT_SYMBOL(pm_idle);
78
79 void (*pm_power_off)(void);
80 EXPORT_SYMBOL(pm_power_off);
81
82 /*
83  * This is our default idle handler.  We need to disable
84  * interrupts here to ensure we don't miss a wakeup call.
85  */
86 void default_idle(void)
87 {
88         if (hlt_counter)
89                 cpu_relax();
90         else {
91                 local_irq_disable();
92                 if (!need_resched()) {
93                         timer_dyn_reprogram();
94                         arch_idle();
95                 }
96                 local_irq_enable();
97         }
98 }
99
100 /*
101  * The idle thread.  We try to conserve power, while trying to keep
102  * overall latency low.  The architecture specific idle is passed
103  * a value to indicate the level of "idleness" of the system.
104  */
105 void cpu_idle(void)
106 {
107         local_fiq_enable();
108
109         /* endless idle loop with no priority at all */
110         while (1) {
111                 void (*idle)(void) = pm_idle;
112
113 #ifdef CONFIG_HOTPLUG_CPU
114                 if (cpu_is_offline(smp_processor_id())) {
115                         leds_event(led_idle_start);
116                         cpu_die();
117                 }
118 #endif
119
120                 if (!idle)
121                         idle = default_idle;
122                 leds_event(led_idle_start);
123                 while (!need_resched())
124                         idle();
125                 leds_event(led_idle_end);
126                 preempt_enable_no_resched();
127                 schedule();
128                 preempt_disable();
129         }
130 }
131
132 static char reboot_mode = 'h';
133
134 int __init reboot_setup(char *str)
135 {
136         reboot_mode = str[0];
137         return 1;
138 }
139
140 __setup("reboot=", reboot_setup);
141
142 void machine_halt(void)
143 {
144 }
145
146
147 void machine_power_off(void)
148 {
149         if (pm_power_off)
150                 pm_power_off();
151 }
152
153
154 void machine_restart(char * __unused)
155 {
156         /*
157          * Clean and disable cache, and turn off interrupts
158          */
159         cpu_proc_fin();
160
161         /*
162          * Tell the mm system that we are going to reboot -
163          * we may need it to insert some 1:1 mappings so that
164          * soft boot works.
165          */
166         setup_mm_for_reboot(reboot_mode);
167
168         /*
169          * Now call the architecture specific reboot code.
170          */
171         arch_reset(reboot_mode);
172
173         /*
174          * Whoops - the architecture was unable to reboot.
175          * Tell the user!
176          */
177         mdelay(1000);
178         printk("Reboot failed -- System halted\n");
179         while (1);
180 }
181
182 void __show_regs(struct pt_regs *regs)
183 {
184         unsigned long flags = condition_codes(regs);
185
186         printk("CPU: %d\n", smp_processor_id());
187         print_symbol("PC is at %s\n", instruction_pointer(regs));
188         print_symbol("LR is at %s\n", regs->ARM_lr);
189         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
190                "sp : %08lx  ip : %08lx  fp : %08lx\n",
191                 instruction_pointer(regs),
192                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
193                 regs->ARM_ip, regs->ARM_fp);
194         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
195                 regs->ARM_r10, regs->ARM_r9,
196                 regs->ARM_r8);
197         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
198                 regs->ARM_r7, regs->ARM_r6,
199                 regs->ARM_r5, regs->ARM_r4);
200         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
201                 regs->ARM_r3, regs->ARM_r2,
202                 regs->ARM_r1, regs->ARM_r0);
203         printk("Flags: %c%c%c%c",
204                 flags & PSR_N_BIT ? 'N' : 'n',
205                 flags & PSR_Z_BIT ? 'Z' : 'z',
206                 flags & PSR_C_BIT ? 'C' : 'c',
207                 flags & PSR_V_BIT ? 'V' : 'v');
208         printk("  IRQs o%s  FIQs o%s  Mode %s%s  Segment %s\n",
209                 interrupts_enabled(regs) ? "n" : "ff",
210                 fast_interrupts_enabled(regs) ? "n" : "ff",
211                 processor_modes[processor_mode(regs)],
212                 thumb_mode(regs) ? " (T)" : "",
213                 get_fs() == get_ds() ? "kernel" : "user");
214         {
215                 unsigned int ctrl, transbase, dac;
216                   __asm__ (
217                 "       mrc p15, 0, %0, c1, c0\n"
218                 "       mrc p15, 0, %1, c2, c0\n"
219                 "       mrc p15, 0, %2, c3, c0\n"
220                 : "=r" (ctrl), "=r" (transbase), "=r" (dac));
221                 printk("Control: %04X  Table: %08X  DAC: %08X\n",
222                         ctrl, transbase, dac);
223         }
224 }
225
226 void show_regs(struct pt_regs * regs)
227 {
228         printk("\n");
229         printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
230         __show_regs(regs);
231         __backtrace();
232 }
233
234 void show_fpregs(struct user_fp *regs)
235 {
236         int i;
237
238         for (i = 0; i < 8; i++) {
239                 unsigned long *p;
240                 char type;
241
242                 p = (unsigned long *)(regs->fpregs + i);
243
244                 switch (regs->ftype[i]) {
245                         case 1: type = 'f'; break;
246                         case 2: type = 'd'; break;
247                         case 3: type = 'e'; break;
248                         default: type = '?'; break;
249                 }
250                 if (regs->init_flag)
251                         type = '?';
252
253                 printk("  f%d(%c): %08lx %08lx %08lx%c",
254                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
255         }
256                         
257
258         printk("FPSR: %08lx FPCR: %08lx\n",
259                 (unsigned long)regs->fpsr,
260                 (unsigned long)regs->fpcr);
261 }
262
263 /*
264  * Task structure and kernel stack allocation.
265  */
266 static unsigned long *thread_info_head;
267 static unsigned int nr_thread_info;
268
269 #define EXTRA_TASK_STRUCT       4
270
271 struct thread_info *alloc_thread_info(struct task_struct *task)
272 {
273         struct thread_info *thread = NULL;
274
275         if (EXTRA_TASK_STRUCT) {
276                 unsigned long *p = thread_info_head;
277
278                 if (p) {
279                         thread_info_head = (unsigned long *)p[0];
280                         nr_thread_info -= 1;
281                 }
282                 thread = (struct thread_info *)p;
283         }
284
285         if (!thread)
286                 thread = (struct thread_info *)
287                            __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
288
289 #ifdef CONFIG_DEBUG_STACK_USAGE
290         /*
291          * The stack must be cleared if you want SYSRQ-T to
292          * give sensible stack usage information
293          */
294         if (thread)
295                 memzero(thread, THREAD_SIZE);
296 #endif
297         return thread;
298 }
299
300 void free_thread_info(struct thread_info *thread)
301 {
302         if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
303                 unsigned long *p = (unsigned long *)thread;
304                 p[0] = (unsigned long)thread_info_head;
305                 thread_info_head = p;
306                 nr_thread_info += 1;
307         } else
308                 free_pages((unsigned long)thread, THREAD_SIZE_ORDER);
309 }
310
311 /*
312  * Free current thread data structures etc..
313  */
314 void exit_thread(void)
315 {
316 }
317
318 static void default_fp_init(union fp_state *fp)
319 {
320         memset(fp, 0, sizeof(union fp_state));
321 }
322
323 void (*fp_init)(union fp_state *) = default_fp_init;
324 EXPORT_SYMBOL(fp_init);
325
326 void flush_thread(void)
327 {
328         struct thread_info *thread = current_thread_info();
329         struct task_struct *tsk = current;
330
331         memset(thread->used_cp, 0, sizeof(thread->used_cp));
332         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
333 #if defined(CONFIG_IWMMXT)
334         iwmmxt_task_release(thread);
335 #endif
336         fp_init(&thread->fpstate);
337 #if defined(CONFIG_VFP)
338         vfp_flush_thread(&thread->vfpstate);
339 #endif
340 }
341
342 void release_thread(struct task_struct *dead_task)
343 {
344 #if defined(CONFIG_VFP)
345         vfp_release_thread(&task_thread_info(dead_task)->vfpstate);
346 #endif
347 #if defined(CONFIG_IWMMXT)
348         iwmmxt_task_release(task_thread_info(dead_task));
349 #endif
350 }
351
352 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
353
354 int
355 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
356             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
357 {
358         struct thread_info *thread = task_thread_info(p);
359         struct pt_regs *childregs = task_pt_regs(p);
360
361         *childregs = *regs;
362         childregs->ARM_r0 = 0;
363         childregs->ARM_sp = stack_start;
364
365         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
366         thread->cpu_context.sp = (unsigned long)childregs;
367         thread->cpu_context.pc = (unsigned long)ret_from_fork;
368
369         if (clone_flags & CLONE_SETTLS)
370                 thread->tp_value = regs->ARM_r3;
371
372         return 0;
373 }
374
375 /*
376  * fill in the fpe structure for a core dump...
377  */
378 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
379 {
380         struct thread_info *thread = current_thread_info();
381         int used_math = thread->used_cp[1] | thread->used_cp[2];
382
383         if (used_math)
384                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
385
386         return used_math != 0;
387 }
388 EXPORT_SYMBOL(dump_fpu);
389
390 /*
391  * fill in the user structure for a core dump..
392  */
393 void dump_thread(struct pt_regs * regs, struct user * dump)
394 {
395         struct task_struct *tsk = current;
396
397         dump->magic = CMAGIC;
398         dump->start_code = tsk->mm->start_code;
399         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
400
401         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
402         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
403         dump->u_ssize = 0;
404
405         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
406         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
407         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
408         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
409         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
410
411         if (dump->start_stack < 0x04000000)
412                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
413
414         dump->regs = *regs;
415         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
416 }
417 EXPORT_SYMBOL(dump_thread);
418
419 /*
420  * Shuffle the argument into the correct register before calling the
421  * thread function.  r1 is the thread argument, r2 is the pointer to
422  * the thread function, and r3 points to the exit function.
423  */
424 extern void kernel_thread_helper(void);
425 asm(    ".section .text\n"
426 "       .align\n"
427 "       .type   kernel_thread_helper, #function\n"
428 "kernel_thread_helper:\n"
429 "       mov     r0, r1\n"
430 "       mov     lr, r3\n"
431 "       mov     pc, r2\n"
432 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
433 "       .previous");
434
435 /*
436  * Create a kernel thread.
437  */
438 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
439 {
440         struct pt_regs regs;
441
442         memset(&regs, 0, sizeof(regs));
443
444         regs.ARM_r1 = (unsigned long)arg;
445         regs.ARM_r2 = (unsigned long)fn;
446         regs.ARM_r3 = (unsigned long)do_exit;
447         regs.ARM_pc = (unsigned long)kernel_thread_helper;
448         regs.ARM_cpsr = SVC_MODE;
449
450         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
451 }
452 EXPORT_SYMBOL(kernel_thread);
453
454 unsigned long get_wchan(struct task_struct *p)
455 {
456         unsigned long fp, lr;
457         unsigned long stack_start, stack_end;
458         int count = 0;
459         if (!p || p == current || p->state == TASK_RUNNING)
460                 return 0;
461
462         stack_start = (unsigned long)end_of_stack(p);
463         stack_end = ((unsigned long)p->thread_info) + THREAD_SIZE;
464
465         fp = thread_saved_fp(p);
466         do {
467                 if (fp < stack_start || fp > stack_end)
468                         return 0;
469                 lr = pc_pointer (((unsigned long *)fp)[-1]);
470                 if (!in_sched_functions(lr))
471                         return lr;
472                 fp = *(unsigned long *) (fp - 12);
473         } while (count ++ < 16);
474         return 0;
475 }
476 EXPORT_SYMBOL(get_wchan);