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