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);
161 * This is our default idle handler.
164 void (*arm_pm_idle)(void);
166 static void default_idle(void)
175 void (*pm_idle)(void) = default_idle;
176 EXPORT_SYMBOL(pm_idle);
179 * The idle thread, has rather strange semantics for calling pm_idle,
180 * but this is what x86 does and we need to do the same, so that
181 * things like cpuidle get called in the same way. The only difference
182 * is that we always respect 'hlt_counter' to prevent low power idle.
188 /* endless idle loop with no priority at all */
190 tick_nohz_idle_enter();
192 leds_event(led_idle_start);
193 while (!need_resched()) {
194 #ifdef CONFIG_HOTPLUG_CPU
195 if (cpu_is_offline(smp_processor_id()))
200 * We need to disable interrupts here
201 * to ensure we don't miss a wakeup call.
204 #ifdef CONFIG_PL310_ERRATA_769419
210 } else if (!need_resched()) {
211 stop_critical_timings();
212 if (cpuidle_idle_call())
214 start_critical_timings();
216 * pm_idle functions must always
217 * return with IRQs enabled.
219 WARN_ON(irqs_disabled());
223 leds_event(led_idle_end);
225 tick_nohz_idle_exit();
226 schedule_preempt_disabled();
230 static char reboot_mode = 'h';
232 int __init reboot_setup(char *str)
234 reboot_mode = str[0];
238 __setup("reboot=", reboot_setup);
240 void machine_shutdown(void)
247 void machine_halt(void)
254 void machine_power_off(void)
261 void machine_restart(char *cmd)
265 arm_pm_restart(reboot_mode, cmd);
267 /* Give a grace period for failure to restart of 1s */
270 /* Whoops - the platform was unable to reboot. Tell the user! */
271 printk("Reboot failed -- System halted\n");
276 void __show_regs(struct pt_regs *regs)
281 printk("CPU: %d %s (%s %.*s)\n",
282 raw_smp_processor_id(), print_tainted(),
283 init_utsname()->release,
284 (int)strcspn(init_utsname()->version, " "),
285 init_utsname()->version);
286 print_symbol("PC is at %s\n", instruction_pointer(regs));
287 print_symbol("LR is at %s\n", regs->ARM_lr);
288 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n"
289 "sp : %08lx ip : %08lx fp : %08lx\n",
290 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
291 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
292 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
293 regs->ARM_r10, regs->ARM_r9,
295 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
296 regs->ARM_r7, regs->ARM_r6,
297 regs->ARM_r5, regs->ARM_r4);
298 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
299 regs->ARM_r3, regs->ARM_r2,
300 regs->ARM_r1, regs->ARM_r0);
302 flags = regs->ARM_cpsr;
303 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
304 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
305 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
306 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
309 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
310 buf, interrupts_enabled(regs) ? "n" : "ff",
311 fast_interrupts_enabled(regs) ? "n" : "ff",
312 processor_modes[processor_mode(regs)],
313 isa_modes[isa_mode(regs)],
314 get_fs() == get_ds() ? "kernel" : "user");
315 #ifdef CONFIG_CPU_CP15
320 #ifdef CONFIG_CPU_CP15_MMU
322 unsigned int transbase, dac;
323 asm("mrc p15, 0, %0, c2, c0\n\t"
324 "mrc p15, 0, %1, c3, c0\n"
325 : "=r" (transbase), "=r" (dac));
326 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
330 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
332 printk("Control: %08x%s\n", ctrl, buf);
337 void show_regs(struct pt_regs * regs)
340 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
345 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
347 EXPORT_SYMBOL_GPL(thread_notify_head);
350 * Free current thread data structures etc..
352 void exit_thread(void)
354 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
357 void flush_thread(void)
359 struct thread_info *thread = current_thread_info();
360 struct task_struct *tsk = current;
362 flush_ptrace_hw_breakpoint(tsk);
364 memset(thread->used_cp, 0, sizeof(thread->used_cp));
365 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
366 memset(&thread->fpstate, 0, sizeof(union fp_state));
368 thread_notify(THREAD_NOTIFY_FLUSH, thread);
371 void release_thread(struct task_struct *dead_task)
375 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
378 copy_thread(unsigned long clone_flags, unsigned long stack_start,
379 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
381 struct thread_info *thread = task_thread_info(p);
382 struct pt_regs *childregs = task_pt_regs(p);
385 childregs->ARM_r0 = 0;
386 childregs->ARM_sp = stack_start;
388 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
389 thread->cpu_context.sp = (unsigned long)childregs;
390 thread->cpu_context.pc = (unsigned long)ret_from_fork;
392 clear_ptrace_hw_breakpoint(p);
394 if (clone_flags & CLONE_SETTLS)
395 thread->tp_value = regs->ARM_r3;
397 thread_notify(THREAD_NOTIFY_COPY, thread);
403 * Fill in the task's elfregs structure for a core dump.
405 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
407 elf_core_copy_regs(elfregs, task_pt_regs(t));
412 * fill in the fpe structure for a core dump...
414 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
416 struct thread_info *thread = current_thread_info();
417 int used_math = thread->used_cp[1] | thread->used_cp[2];
420 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
422 return used_math != 0;
424 EXPORT_SYMBOL(dump_fpu);
427 * Shuffle the argument into the correct register before calling the
428 * thread function. r4 is the thread argument, r5 is the pointer to
429 * the thread function, and r6 points to the exit function.
431 extern void kernel_thread_helper(void);
432 asm( ".pushsection .text\n"
434 " .type kernel_thread_helper, #function\n"
435 "kernel_thread_helper:\n"
436 #ifdef CONFIG_TRACE_IRQFLAGS
437 " bl trace_hardirqs_on\n"
443 " .size kernel_thread_helper, . - kernel_thread_helper\n"
446 #ifdef CONFIG_ARM_UNWIND
447 extern void kernel_thread_exit(long code);
448 asm( ".pushsection .text\n"
450 " .type kernel_thread_exit, #function\n"
451 "kernel_thread_exit:\n"
457 " .size kernel_thread_exit, . - kernel_thread_exit\n"
460 #define kernel_thread_exit do_exit
464 * Create a kernel thread.
466 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
470 memset(®s, 0, sizeof(regs));
472 regs.ARM_r4 = (unsigned long)arg;
473 regs.ARM_r5 = (unsigned long)fn;
474 regs.ARM_r6 = (unsigned long)kernel_thread_exit;
475 regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
476 regs.ARM_pc = (unsigned long)kernel_thread_helper;
477 regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
479 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
481 EXPORT_SYMBOL(kernel_thread);
483 unsigned long get_wchan(struct task_struct *p)
485 struct stackframe frame;
487 if (!p || p == current || p->state == TASK_RUNNING)
490 frame.fp = thread_saved_fp(p);
491 frame.sp = thread_saved_sp(p);
492 frame.lr = 0; /* recovered from the stack */
493 frame.pc = thread_saved_pc(p);
495 int ret = unwind_frame(&frame);
498 if (!in_sched_functions(frame.pc))
500 } while (count ++ < 16);
504 unsigned long arch_randomize_brk(struct mm_struct *mm)
506 unsigned long range_end = mm->brk + 0x02000000;
507 return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
512 * The vectors page is always readable from user space for the
513 * atomic helpers and the signal restart code. Insert it into the
514 * gate_vma so that it is visible through ptrace and /proc/<pid>/mem.
516 static struct vm_area_struct gate_vma;
518 static int __init gate_vma_init(void)
520 gate_vma.vm_start = 0xffff0000;
521 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
522 gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
523 gate_vma.vm_flags = VM_READ | VM_EXEC |
524 VM_MAYREAD | VM_MAYEXEC;
527 arch_initcall(gate_vma_init);
529 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
534 int in_gate_area(struct mm_struct *mm, unsigned long addr)
536 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
539 int in_gate_area_no_mm(unsigned long addr)
541 return in_gate_area(NULL, addr);
544 const char *arch_vma_name(struct vm_area_struct *vma)
546 return (vma == &gate_vma) ? "[vectors]" : NULL;