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/module.h>
14 #include <linux/sched.h>
15 #include <linux/kernel.h>
16 #include <linux/mm.h>
17 #include <linux/stddef.h>
18 #include <linux/unistd.h>
19 #include <linux/slab.h>
20 #include <linux/user.h>
21 #include <linux/delay.h>
22 #include <linux/reboot.h>
23 #include <linux/interrupt.h>
24 #include <linux/kallsyms.h>
25 #include <linux/init.h>
26 #include <linux/cpu.h>
27 #include <linux/elfcore.h>
28 #include <linux/pm.h>
29 #include <linux/tick.h>
30 #include <linux/utsname.h>
31 #include <linux/uaccess.h>
32
33 #include <asm/leds.h>
34 #include <asm/processor.h>
35 #include <asm/system.h>
36 #include <asm/thread_notify.h>
37 #include <asm/stacktrace.h>
38 #include <asm/mach/time.h>
39
40 static const char *processor_modes[] = {
41 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
42 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
43 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
44 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
45 };
46
47 static const char *isa_modes[] = {
48 "ARM" , "Thumb" , "Jazelle", "ThumbEE"
49 };
50
51 extern void setup_mm_for_reboot(char mode);
52
53 static volatile int hlt_counter;
54
55 #include <mach/system.h>
56
57 void disable_hlt(void)
58 {
59 hlt_counter++;
60 }
61
62 EXPORT_SYMBOL(disable_hlt);
63
64 void enable_hlt(void)
65 {
66 hlt_counter--;
67 }
68
69 EXPORT_SYMBOL(enable_hlt);
70
71 static int __init nohlt_setup(char *__unused)
72 {
73 hlt_counter = 1;
74 return 1;
75 }
76
77 static int __init hlt_setup(char *__unused)
78 {
79 hlt_counter = 0;
80 return 1;
81 }
82
83 __setup("nohlt", nohlt_setup);
84 __setup("hlt", hlt_setup);
85
86 void arm_machine_restart(char mode, const char *cmd)
87 {
88 /*
89 * Clean and disable cache, and turn off interrupts
90 */
91 cpu_proc_fin();
92
93 /*
94 * Tell the mm system that we are going to reboot -
95 * we may need it to insert some 1:1 mappings so that
96 * soft boot works.
97 */
98 setup_mm_for_reboot(mode);
99
100 /*
101 * Now call the architecture specific reboot code.
102 */
103 arch_reset(mode, cmd);
104
105 /*
106 * Whoops - the architecture was unable to reboot.
107 * Tell the user!
108 */
109 mdelay(1000);
110 printk("Reboot failed -- System halted\n");
111 while (1);
112 }
113
114 /*
115 * Function pointers to optional machine specific functions
116 */
117 void (*pm_power_off)(void);
118 EXPORT_SYMBOL(pm_power_off);
119
120 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
121 EXPORT_SYMBOL_GPL(arm_pm_restart);
122
123
124 /*
125 * This is our default idle handler. We need to disable
126 * interrupts here to ensure we don't miss a wakeup call.
127 */
128 static void default_idle(void)
129 {
130 if (!need_resched())
131 arch_idle();
132 local_irq_enable();
133 }
134
135 void (*pm_idle)(void) = default_idle;
136 EXPORT_SYMBOL(pm_idle);
137
138 /*
139 * The idle thread, has rather strange semantics for calling pm_idle,
140 * but this is what x86 does and we need to do the same, so that
141 * things like cpuidle get called in the same way. The only difference
142 * is that we always respect 'hlt_counter' to prevent low power idle.
143 */
144 void cpu_idle(void)
145 {
146 local_fiq_enable();
147
148 /* endless idle loop with no priority at all */
149 while (1) {
150 tick_nohz_stop_sched_tick(1);
151 leds_event(led_idle_start);
152 while (!need_resched()) {
153 #ifdef CONFIG_HOTPLUG_CPU
154 if (cpu_is_offline(smp_processor_id()))
155 cpu_die();
156 #endif
157
158 local_irq_disable();
159 if (hlt_counter) {
160 local_irq_enable();
161 cpu_relax();
162 } else {
163 stop_critical_timings();
164 pm_idle();
165 start_critical_timings();
166 /*
167 * This will eventually be removed - pm_idle
168 * functions should always return with IRQs
169 * enabled.
170 */
171 WARN_ON(irqs_disabled());
172 local_irq_enable();
173 }
174 }
175 leds_event(led_idle_end);
176 tick_nohz_restart_sched_tick();
177 preempt_enable_no_resched();
178 schedule();
179 preempt_disable();
180 }
181 }
182
183 static char reboot_mode = 'h';
184
185 int __init reboot_setup(char *str)
186 {
187 reboot_mode = str[0];
188 return 1;
189 }
190
191 __setup("reboot=", reboot_setup);
192
193 void machine_halt(void)
194 {
195 }
196
197
198 void machine_power_off(void)
199 {
200 if (pm_power_off)
201 pm_power_off();
202 }
203
204 void machine_restart(char *cmd)
205 {
206 arm_pm_restart(reboot_mode, cmd);
207 }
208
209 void __show_regs(struct pt_regs *regs)
210 {
211 unsigned long flags;
212 char buf[64];
213
214 printk("CPU: %d %s (%s %.*s)\n",
215 smp_processor_id(), print_tainted(), init_utsname()->release,
216 (int)strcspn(init_utsname()->version, " "),
217 init_utsname()->version);
218 print_symbol("PC is at %s\n", instruction_pointer(regs));
219 print_symbol("LR is at %s\n", regs->ARM_lr);
220 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n"
221 "sp : %08lx ip : %08lx fp : %08lx\n",
222 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
223 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
224 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
225 regs->ARM_r10, regs->ARM_r9,
226 regs->ARM_r8);
227 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
228 regs->ARM_r7, regs->ARM_r6,
229 regs->ARM_r5, regs->ARM_r4);
230 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
231 regs->ARM_r3, regs->ARM_r2,
232 regs->ARM_r1, regs->ARM_r0);
233
234 flags = regs->ARM_cpsr;
235 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
236 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
237 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
238 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
239 buf[4] = '\0';
240
241 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
242 buf, interrupts_enabled(regs) ? "n" : "ff",
243 fast_interrupts_enabled(regs) ? "n" : "ff",
244 processor_modes[processor_mode(regs)],
245 isa_modes[isa_mode(regs)],
246 get_fs() == get_ds() ? "kernel" : "user");
247 #ifdef CONFIG_CPU_CP15
248 {
249 unsigned int ctrl;
250
251 buf[0] = '\0';
252 #ifdef CONFIG_CPU_CP15_MMU
253 {
254 unsigned int transbase, dac;
255 asm("mrc p15, 0, %0, c2, c0\n\t"
256 "mrc p15, 0, %1, c3, c0\n"
257 : "=r" (transbase), "=r" (dac));
258 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
259 transbase, dac);
260 }
261 #endif
262 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
263
264 printk("Control: %08x%s\n", ctrl, buf);
265 }
266 #endif
267 }
268
269 void show_regs(struct pt_regs * regs)
270 {
271 printk("\n");
272 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
273 __show_regs(regs);
274 __backtrace();
275 }
276
277 /*
278 * Free current thread data structures etc..
279 */
280 void exit_thread(void)
281 {
282 }
283
284 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
285
286 EXPORT_SYMBOL_GPL(thread_notify_head);
287
288 void flush_thread(void)
289 {
290 struct thread_info *thread = current_thread_info();
291 struct task_struct *tsk = current;
292
293 memset(thread->used_cp, 0, sizeof(thread->used_cp));
294 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
295 memset(&thread->fpstate, 0, sizeof(union fp_state));
296
297 thread_notify(THREAD_NOTIFY_FLUSH, thread);
298 }
299
300 void release_thread(struct task_struct *dead_task)
301 {
302 struct thread_info *thread = task_thread_info(dead_task);
303
304 thread_notify(THREAD_NOTIFY_RELEASE, thread);
305 }
306
307 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
308
309 int
310 copy_thread(unsigned long clone_flags, unsigned long stack_start,
311 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
312 {
313 struct thread_info *thread = task_thread_info(p);
314 struct pt_regs *childregs = task_pt_regs(p);
315
316 *childregs = *regs;
317 childregs->ARM_r0 = 0;
318 childregs->ARM_sp = stack_start;
319
320 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
321 thread->cpu_context.sp = (unsigned long)childregs;
322 thread->cpu_context.pc = (unsigned long)ret_from_fork;
323
324 if (clone_flags & CLONE_SETTLS)
325 thread->tp_value = regs->ARM_r3;
326
327 return 0;
328 }
329
330 /*
331 * fill in the fpe structure for a core dump...
332 */
333 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
334 {
335 struct thread_info *thread = current_thread_info();
336 int used_math = thread->used_cp[1] | thread->used_cp[2];
337
338 if (used_math)
339 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
340
341 return used_math != 0;
342 }
343 EXPORT_SYMBOL(dump_fpu);
344
345 /*
346 * Shuffle the argument into the correct register before calling the
347 * thread function. r1 is the thread argument, r2 is the pointer to
348 * the thread function, and r3 points to the exit function.
349 */
350 extern void kernel_thread_helper(void);
351 asm( ".section .text\n"
352 " .align\n"
353 " .type kernel_thread_helper, #function\n"
354 "kernel_thread_helper:\n"
355 " mov r0, r1\n"
356 " mov lr, r3\n"
357 " mov pc, r2\n"
358 " .size kernel_thread_helper, . - kernel_thread_helper\n"
359 " .previous");
360
361 #ifdef CONFIG_ARM_UNWIND
362 extern void kernel_thread_exit(long code);
363 asm( ".section .text\n"
364 " .align\n"
365 " .type kernel_thread_exit, #function\n"
366 "kernel_thread_exit:\n"
367 " .fnstart\n"
368 " .cantunwind\n"
369 " bl do_exit\n"
370 " nop\n"
371 " .fnend\n"
372 " .size kernel_thread_exit, . - kernel_thread_exit\n"
373 " .previous");
374 #else
375 #define kernel_thread_exit do_exit
376 #endif
377
378 /*
379 * Create a kernel thread.
380 */
381 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
382 {
383 struct pt_regs regs;
384
385 memset(®s, 0, sizeof(regs));
386
387 regs.ARM_r1 = (unsigned long)arg;
388 regs.ARM_r2 = (unsigned long)fn;
389 regs.ARM_r3 = (unsigned long)kernel_thread_exit;
390 regs.ARM_pc = (unsigned long)kernel_thread_helper;
391 regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE;
392
393 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
394 }
395 EXPORT_SYMBOL(kernel_thread);
396
397 unsigned long get_wchan(struct task_struct *p)
398 {
399 struct stackframe frame;
400 int count = 0;
401 if (!p || p == current || p->state == TASK_RUNNING)
402 return 0;
403
404 frame.fp = thread_saved_fp(p);
405 frame.sp = thread_saved_sp(p);
406 frame.lr = 0; /* recovered from the stack */
407 frame.pc = thread_saved_pc(p);
408 do {
409 int ret = unwind_frame(&frame);
410 if (ret < 0)
411 return 0;
412 if (!in_sched_functions(frame.pc))
413 return frame.pc;
414 } while (count ++ < 16);
415 return 0;
416 }
417
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