2 * linux/arch/arm/kernel/process.c
4 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
5 * Original Copyright (C) 1995 Linus Torvalds
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.
13 #include <linux/export.h>
14 #include <linux/sched.h>
15 #include <linux/kernel.h>
17 #include <linux/stddef.h>
18 #include <linux/unistd.h>
19 #include <linux/user.h>
20 #include <linux/delay.h>
21 #include <linux/reboot.h>
22 #include <linux/interrupt.h>
23 #include <linux/kallsyms.h>
24 #include <linux/init.h>
25 #include <linux/cpu.h>
26 #include <linux/elfcore.h>
28 #include <linux/tick.h>
29 #include <linux/utsname.h>
30 #include <linux/uaccess.h>
31 #include <linux/random.h>
32 #include <linux/hw_breakpoint.h>
33 #include <linux/cpuidle.h>
35 #include <asm/cacheflush.h>
37 #include <asm/processor.h>
38 #include <asm/thread_notify.h>
39 #include <asm/stacktrace.h>
40 #include <asm/mach/time.h>
42 #ifdef CONFIG_CC_STACKPROTECTOR
43 #include <linux/stackprotector.h>
44 unsigned long __stack_chk_guard __read_mostly;
45 EXPORT_SYMBOL(__stack_chk_guard);
48 static const char *processor_modes[] = {
49 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
50 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
51 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
52 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
55 static const char *isa_modes[] = {
56 "ARM" , "Thumb" , "Jazelle", "ThumbEE"
59 extern void setup_mm_for_reboot(void);
61 static volatile int hlt_counter;
63 void disable_hlt(void)
68 EXPORT_SYMBOL(disable_hlt);
75 EXPORT_SYMBOL(enable_hlt);
77 static int __init nohlt_setup(char *__unused)
83 static int __init hlt_setup(char *__unused)
89 __setup("nohlt", nohlt_setup);
90 __setup("hlt", hlt_setup);
92 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
93 typedef void (*phys_reset_t)(unsigned long);
96 * A temporary stack to use for CPU reset. This is static so that we
97 * don't clobber it with the identity mapping. When running with this
98 * stack, any references to the current task *will not work* so you
99 * should really do as little as possible before jumping to your reset
102 static u64 soft_restart_stack[16];
104 static void __soft_restart(void *addr)
106 phys_reset_t phys_reset;
108 /* Take out a flat memory mapping. */
109 setup_mm_for_reboot();
111 /* Clean and invalidate caches */
114 /* Turn off caching */
117 /* Push out any further dirty data, and ensure cache is empty */
120 /* Switch to the identity mapping. */
121 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
122 phys_reset((unsigned long)addr);
124 /* Should never get here. */
128 void soft_restart(unsigned long addr)
130 u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
132 /* Disable interrupts first */
136 /* Disable the L2 if we're the last man standing. */
137 if (num_online_cpus() == 1)
140 /* Change to the new stack and continue with the reset. */
141 call_with_stack(__soft_restart, (void *)addr, (void *)stack);
143 /* Should never get here. */
147 static void null_restart(char mode, const char *cmd)
152 * Function pointers to optional machine specific functions
154 void (*pm_power_off)(void);
155 EXPORT_SYMBOL(pm_power_off);
157 void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
158 EXPORT_SYMBOL_GPL(arm_pm_restart);
160 static void do_nothing(void *unused)
165 * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
166 * pm_idle and update to new pm_idle value. Required while changing pm_idle
167 * handler on SMP systems.
169 * Caller must have changed pm_idle to the new value before the call. Old
170 * pm_idle value will not be used by any CPU after the return of this function.
172 void cpu_idle_wait(void)
175 /* kick all the CPUs so that they exit out of pm_idle */
176 smp_call_function(do_nothing, NULL, 1);
178 EXPORT_SYMBOL_GPL(cpu_idle_wait);
181 * This is our default idle handler.
184 void (*arm_pm_idle)(void);
186 static void default_idle(void)
195 void (*pm_idle)(void) = default_idle;
196 EXPORT_SYMBOL(pm_idle);
199 * The idle thread, has rather strange semantics for calling pm_idle,
200 * but this is what x86 does and we need to do the same, so that
201 * things like cpuidle get called in the same way. The only difference
202 * is that we always respect 'hlt_counter' to prevent low power idle.
208 /* endless idle loop with no priority at all */
210 tick_nohz_idle_enter();
212 leds_event(led_idle_start);
213 while (!need_resched()) {
214 #ifdef CONFIG_HOTPLUG_CPU
215 if (cpu_is_offline(smp_processor_id()))
220 * We need to disable interrupts here
221 * to ensure we don't miss a wakeup call.
224 #ifdef CONFIG_PL310_ERRATA_769419
230 } else if (!need_resched()) {
231 stop_critical_timings();
232 if (cpuidle_idle_call())
234 start_critical_timings();
236 * pm_idle functions must always
237 * return with IRQs enabled.
239 WARN_ON(irqs_disabled());
243 leds_event(led_idle_end);
245 tick_nohz_idle_exit();
246 schedule_preempt_disabled();
250 static char reboot_mode = 'h';
252 int __init reboot_setup(char *str)
254 reboot_mode = str[0];
258 __setup("reboot=", reboot_setup);
260 void machine_shutdown(void)
267 void machine_halt(void)
273 void machine_power_off(void)
280 void machine_restart(char *cmd)
284 arm_pm_restart(reboot_mode, cmd);
286 /* Give a grace period for failure to restart of 1s */
289 /* Whoops - the platform was unable to reboot. Tell the user! */
290 printk("Reboot failed -- System halted\n");
294 void __show_regs(struct pt_regs *regs)
299 printk("CPU: %d %s (%s %.*s)\n",
300 raw_smp_processor_id(), print_tainted(),
301 init_utsname()->release,
302 (int)strcspn(init_utsname()->version, " "),
303 init_utsname()->version);
304 print_symbol("PC is at %s\n", instruction_pointer(regs));
305 print_symbol("LR is at %s\n", regs->ARM_lr);
306 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n"
307 "sp : %08lx ip : %08lx fp : %08lx\n",
308 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
309 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
310 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
311 regs->ARM_r10, regs->ARM_r9,
313 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
314 regs->ARM_r7, regs->ARM_r6,
315 regs->ARM_r5, regs->ARM_r4);
316 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
317 regs->ARM_r3, regs->ARM_r2,
318 regs->ARM_r1, regs->ARM_r0);
320 flags = regs->ARM_cpsr;
321 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
322 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
323 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
324 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
327 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
328 buf, interrupts_enabled(regs) ? "n" : "ff",
329 fast_interrupts_enabled(regs) ? "n" : "ff",
330 processor_modes[processor_mode(regs)],
331 isa_modes[isa_mode(regs)],
332 get_fs() == get_ds() ? "kernel" : "user");
333 #ifdef CONFIG_CPU_CP15
338 #ifdef CONFIG_CPU_CP15_MMU
340 unsigned int transbase, dac;
341 asm("mrc p15, 0, %0, c2, c0\n\t"
342 "mrc p15, 0, %1, c3, c0\n"
343 : "=r" (transbase), "=r" (dac));
344 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
348 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
350 printk("Control: %08x%s\n", ctrl, buf);
355 void show_regs(struct pt_regs * regs)
358 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
363 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
365 EXPORT_SYMBOL_GPL(thread_notify_head);
368 * Free current thread data structures etc..
370 void exit_thread(void)
372 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
375 void flush_thread(void)
377 struct thread_info *thread = current_thread_info();
378 struct task_struct *tsk = current;
380 flush_ptrace_hw_breakpoint(tsk);
382 memset(thread->used_cp, 0, sizeof(thread->used_cp));
383 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
384 memset(&thread->fpstate, 0, sizeof(union fp_state));
386 thread_notify(THREAD_NOTIFY_FLUSH, thread);
389 void release_thread(struct task_struct *dead_task)
393 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
396 copy_thread(unsigned long clone_flags, unsigned long stack_start,
397 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
399 struct thread_info *thread = task_thread_info(p);
400 struct pt_regs *childregs = task_pt_regs(p);
403 childregs->ARM_r0 = 0;
404 childregs->ARM_sp = stack_start;
406 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
407 thread->cpu_context.sp = (unsigned long)childregs;
408 thread->cpu_context.pc = (unsigned long)ret_from_fork;
410 clear_ptrace_hw_breakpoint(p);
412 if (clone_flags & CLONE_SETTLS)
413 thread->tp_value = regs->ARM_r3;
415 thread_notify(THREAD_NOTIFY_COPY, thread);
421 * Fill in the task's elfregs structure for a core dump.
423 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
425 elf_core_copy_regs(elfregs, task_pt_regs(t));
430 * fill in the fpe structure for a core dump...
432 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
434 struct thread_info *thread = current_thread_info();
435 int used_math = thread->used_cp[1] | thread->used_cp[2];
438 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
440 return used_math != 0;
442 EXPORT_SYMBOL(dump_fpu);
445 * Shuffle the argument into the correct register before calling the
446 * thread function. r4 is the thread argument, r5 is the pointer to
447 * the thread function, and r6 points to the exit function.
449 extern void kernel_thread_helper(void);
450 asm( ".pushsection .text\n"
452 " .type kernel_thread_helper, #function\n"
453 "kernel_thread_helper:\n"
454 #ifdef CONFIG_TRACE_IRQFLAGS
455 " bl trace_hardirqs_on\n"
461 " .size kernel_thread_helper, . - kernel_thread_helper\n"
464 #ifdef CONFIG_ARM_UNWIND
465 extern void kernel_thread_exit(long code);
466 asm( ".pushsection .text\n"
468 " .type kernel_thread_exit, #function\n"
469 "kernel_thread_exit:\n"
475 " .size kernel_thread_exit, . - kernel_thread_exit\n"
478 #define kernel_thread_exit do_exit
482 * Create a kernel thread.
484 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
488 memset(®s, 0, sizeof(regs));
490 regs.ARM_r4 = (unsigned long)arg;
491 regs.ARM_r5 = (unsigned long)fn;
492 regs.ARM_r6 = (unsigned long)kernel_thread_exit;
493 regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
494 regs.ARM_pc = (unsigned long)kernel_thread_helper;
495 regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
497 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
499 EXPORT_SYMBOL(kernel_thread);
501 unsigned long get_wchan(struct task_struct *p)
503 struct stackframe frame;
505 if (!p || p == current || p->state == TASK_RUNNING)
508 frame.fp = thread_saved_fp(p);
509 frame.sp = thread_saved_sp(p);
510 frame.lr = 0; /* recovered from the stack */
511 frame.pc = thread_saved_pc(p);
513 int ret = unwind_frame(&frame);
516 if (!in_sched_functions(frame.pc))
518 } while (count ++ < 16);
522 unsigned long arch_randomize_brk(struct mm_struct *mm)
524 unsigned long range_end = mm->brk + 0x02000000;
525 return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
530 * The vectors page is always readable from user space for the
531 * atomic helpers and the signal restart code. Let's declare a mapping
532 * for it so it is visible through ptrace and /proc/<pid>/mem.
535 int vectors_user_mapping(void)
537 struct mm_struct *mm = current->mm;
538 return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
540 VM_MAYREAD | VM_MAYEXEC | VM_RESERVED,
544 const char *arch_vma_name(struct vm_area_struct *vma)
546 return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;