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/leds.h>
34 #include <linux/reboot.h>
36 #include <asm/cacheflush.h>
37 #include <asm/idmap.h>
38 #include <asm/processor.h>
39 #include <asm/thread_notify.h>
40 #include <asm/stacktrace.h>
41 #include <asm/system_misc.h>
42 #include <asm/mach/time.h>
45 #ifdef CONFIG_CC_STACKPROTECTOR
46 #include <linux/stackprotector.h>
47 unsigned long __stack_chk_guard __read_mostly;
48 EXPORT_SYMBOL(__stack_chk_guard);
51 static const char *processor_modes[] __maybe_unused = {
52 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
53 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
54 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
55 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
58 static const char *isa_modes[] __maybe_unused = {
59 "ARM" , "Thumb" , "Jazelle", "ThumbEE"
62 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
63 typedef void (*phys_reset_t)(unsigned long);
66 * A temporary stack to use for CPU reset. This is static so that we
67 * don't clobber it with the identity mapping. When running with this
68 * stack, any references to the current task *will not work* so you
69 * should really do as little as possible before jumping to your reset
72 static u64 soft_restart_stack[16];
74 static void __soft_restart(void *addr)
76 phys_reset_t phys_reset;
78 /* Take out a flat memory mapping. */
79 setup_mm_for_reboot();
81 /* Clean and invalidate caches */
84 /* Turn off caching */
87 /* Push out any further dirty data, and ensure cache is empty */
90 /* Switch to the identity mapping. */
91 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
92 phys_reset((unsigned long)addr);
94 /* Should never get here. */
98 void soft_restart(unsigned long addr)
100 u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
102 /* Disable interrupts first */
103 raw_local_irq_disable();
106 /* Disable the L2 if we're the last man standing. */
107 if (num_online_cpus() == 1)
110 /* Change to the new stack and continue with the reset. */
111 call_with_stack(__soft_restart, (void *)addr, (void *)stack);
113 /* Should never get here. */
117 static void null_restart(enum reboot_mode reboot_mode, const char *cmd)
122 * Function pointers to optional machine specific functions
124 void (*pm_power_off)(void);
125 EXPORT_SYMBOL(pm_power_off);
127 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd) = null_restart;
128 EXPORT_SYMBOL_GPL(arm_pm_restart);
131 * This is our default idle handler.
134 void (*arm_pm_idle)(void);
137 * Called from the core idle loop.
140 void arch_cpu_idle(void)
149 void arch_cpu_idle_prepare(void)
154 void arch_cpu_idle_enter(void)
156 ledtrig_cpu(CPU_LED_IDLE_START);
157 #ifdef CONFIG_PL310_ERRATA_769419
162 void arch_cpu_idle_exit(void)
164 ledtrig_cpu(CPU_LED_IDLE_END);
167 #ifdef CONFIG_HOTPLUG_CPU
168 void arch_cpu_idle_dead(void)
175 * Called by kexec, immediately prior to machine_kexec().
177 * This must completely disable all secondary CPUs; simply causing those CPUs
178 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
179 * kexec'd kernel to use any and all RAM as it sees fit, without having to
180 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
181 * functionality embodied in disable_nonboot_cpus() to achieve this.
183 void machine_shutdown(void)
185 disable_nonboot_cpus();
189 * Halting simply requires that the secondary CPUs stop performing any
190 * activity (executing tasks, handling interrupts). smp_send_stop()
193 void machine_halt(void)
203 * Power-off simply requires that the secondary CPUs stop performing any
204 * activity (executing tasks, handling interrupts). smp_send_stop()
205 * achieves this. When the system power is turned off, it will take all CPUs
208 void machine_power_off(void)
218 * Restart requires that the secondary CPUs stop performing any activity
219 * while the primary CPU resets the system. Systems with a single CPU can
220 * use soft_restart() as their machine descriptor's .restart hook, since that
221 * will cause the only available CPU to reset. Systems with multiple CPUs must
222 * provide a HW restart implementation, to ensure that all CPUs reset at once.
223 * This is required so that any code running after reset on the primary CPU
224 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
225 * executing pre-reset code, and using RAM that the primary CPU's code wishes
226 * to use. Implementing such co-ordination would be essentially impossible.
228 void machine_restart(char *cmd)
233 arm_pm_restart(reboot_mode, cmd);
235 /* Give a grace period for failure to restart of 1s */
238 /* Whoops - the platform was unable to reboot. Tell the user! */
239 printk("Reboot failed -- System halted\n");
244 void __show_regs(struct pt_regs *regs)
249 show_regs_print_info(KERN_DEFAULT);
251 print_symbol("PC is at %s\n", instruction_pointer(regs));
252 print_symbol("LR is at %s\n", regs->ARM_lr);
253 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n"
254 "sp : %08lx ip : %08lx fp : %08lx\n",
255 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
256 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
257 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
258 regs->ARM_r10, regs->ARM_r9,
260 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
261 regs->ARM_r7, regs->ARM_r6,
262 regs->ARM_r5, regs->ARM_r4);
263 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
264 regs->ARM_r3, regs->ARM_r2,
265 regs->ARM_r1, regs->ARM_r0);
267 flags = regs->ARM_cpsr;
268 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
269 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
270 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
271 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
274 #ifndef CONFIG_CPU_V7M
275 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
276 buf, interrupts_enabled(regs) ? "n" : "ff",
277 fast_interrupts_enabled(regs) ? "n" : "ff",
278 processor_modes[processor_mode(regs)],
279 isa_modes[isa_mode(regs)],
280 get_fs() == get_ds() ? "kernel" : "user");
282 printk("xPSR: %08lx\n", regs->ARM_cpsr);
285 #ifdef CONFIG_CPU_CP15
290 #ifdef CONFIG_CPU_CP15_MMU
292 unsigned int transbase, dac;
293 asm("mrc p15, 0, %0, c2, c0\n\t"
294 "mrc p15, 0, %1, c3, c0\n"
295 : "=r" (transbase), "=r" (dac));
296 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
300 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
302 printk("Control: %08x%s\n", ctrl, buf);
307 void show_regs(struct pt_regs * regs)
313 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
315 EXPORT_SYMBOL_GPL(thread_notify_head);
318 * Free current thread data structures etc..
320 void exit_thread(void)
322 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
325 void flush_thread(void)
327 struct thread_info *thread = current_thread_info();
328 struct task_struct *tsk = current;
330 flush_ptrace_hw_breakpoint(tsk);
332 memset(thread->used_cp, 0, sizeof(thread->used_cp));
333 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
334 memset(&thread->fpstate, 0, sizeof(union fp_state));
338 thread_notify(THREAD_NOTIFY_FLUSH, thread);
341 void release_thread(struct task_struct *dead_task)
345 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
348 copy_thread(unsigned long clone_flags, unsigned long stack_start,
349 unsigned long stk_sz, struct task_struct *p)
351 struct thread_info *thread = task_thread_info(p);
352 struct pt_regs *childregs = task_pt_regs(p);
354 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
356 if (likely(!(p->flags & PF_KTHREAD))) {
357 *childregs = *current_pt_regs();
358 childregs->ARM_r0 = 0;
360 childregs->ARM_sp = stack_start;
362 memset(childregs, 0, sizeof(struct pt_regs));
363 thread->cpu_context.r4 = stk_sz;
364 thread->cpu_context.r5 = stack_start;
365 childregs->ARM_cpsr = SVC_MODE;
367 thread->cpu_context.pc = (unsigned long)ret_from_fork;
368 thread->cpu_context.sp = (unsigned long)childregs;
370 clear_ptrace_hw_breakpoint(p);
372 if (clone_flags & CLONE_SETTLS)
373 thread->tp_value[0] = childregs->ARM_r3;
374 thread->tp_value[1] = get_tpuser();
376 thread_notify(THREAD_NOTIFY_COPY, thread);
382 * Fill in the task's elfregs structure for a core dump.
384 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
386 elf_core_copy_regs(elfregs, task_pt_regs(t));
391 * fill in the fpe structure for a core dump...
393 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
395 struct thread_info *thread = current_thread_info();
396 int used_math = thread->used_cp[1] | thread->used_cp[2];
399 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
401 return used_math != 0;
403 EXPORT_SYMBOL(dump_fpu);
405 unsigned long get_wchan(struct task_struct *p)
407 struct stackframe frame;
408 unsigned long stack_page;
410 if (!p || p == current || p->state == TASK_RUNNING)
413 frame.fp = thread_saved_fp(p);
414 frame.sp = thread_saved_sp(p);
415 frame.lr = 0; /* recovered from the stack */
416 frame.pc = thread_saved_pc(p);
417 stack_page = (unsigned long)task_stack_page(p);
419 if (frame.sp < stack_page ||
420 frame.sp >= stack_page + THREAD_SIZE ||
421 unwind_frame(&frame) < 0)
423 if (!in_sched_functions(frame.pc))
425 } while (count ++ < 16);
429 unsigned long arch_randomize_brk(struct mm_struct *mm)
431 unsigned long range_end = mm->brk + 0x02000000;
432 return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
436 #ifdef CONFIG_KUSER_HELPERS
438 * The vectors page is always readable from user space for the
439 * atomic helpers. Insert it into the gate_vma so that it is visible
440 * through ptrace and /proc/<pid>/mem.
442 static struct vm_area_struct gate_vma = {
443 .vm_start = 0xffff0000,
444 .vm_end = 0xffff0000 + PAGE_SIZE,
445 .vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
448 static int __init gate_vma_init(void)
450 gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
453 arch_initcall(gate_vma_init);
455 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
460 int in_gate_area(struct mm_struct *mm, unsigned long addr)
462 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
465 int in_gate_area_no_mm(unsigned long addr)
467 return in_gate_area(NULL, addr);
469 #define is_gate_vma(vma) ((vma) == &gate_vma)
471 #define is_gate_vma(vma) 0
474 const char *arch_vma_name(struct vm_area_struct *vma)
476 return is_gate_vma(vma) ? "[vectors]" : NULL;
479 /* If possible, provide a placement hint at a random offset from the
480 * stack for the signal page.
482 static unsigned long sigpage_addr(const struct mm_struct *mm,
485 unsigned long offset;
491 first = PAGE_ALIGN(mm->start_stack);
493 last = TASK_SIZE - (npages << PAGE_SHIFT);
495 /* No room after stack? */
499 /* Just enough room? */
503 slots = ((last - first) >> PAGE_SHIFT) + 1;
505 offset = get_random_int() % slots;
507 addr = first + (offset << PAGE_SHIFT);
512 static struct page *signal_page;
513 extern struct page *get_signal_page(void);
515 static const struct vm_special_mapping sigpage_mapping = {
517 .pages = &signal_page,
520 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
522 struct mm_struct *mm = current->mm;
523 struct vm_area_struct *vma;
529 signal_page = get_signal_page();
533 down_write(&mm->mmap_sem);
534 hint = sigpage_addr(mm, 1);
535 addr = get_unmapped_area(NULL, hint, PAGE_SIZE, 0, 0);
536 if (IS_ERR_VALUE(addr)) {
541 vma = _install_special_mapping(mm, addr, PAGE_SIZE,
542 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
550 mm->context.sigpage = addr;
553 up_write(&mm->mmap_sem);