#include <linux/errno.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/smp.h>#include <linux/prctl.h>#include <linux/slab.h>#include <linux/sched.h>#include <linux/module.h>#include <linux/pm.h>#include <linux/clockchips.h>#include <linux/random.h>#include <linux/user-return-notifier.h>#include <linux/dmi.h>#include <linux/utsname.h>#include <linux/stackprotector.h>#include <linux/tick.h>#include <linux/cpuidle.h>#include <trace/events/power.h>#include <linux/hw_breakpoint.h>#include <asm/cpu.h>#include <asm/apic.h>#include <asm/syscalls.h>#include <asm/idle.h>#include <asm/uaccess.h>#include <asm/i387.h>#include <asm/fpu-internal.h>#include <asm/debugreg.h>#include <asm/nmi.h> /* * per-CPU TSS segments. Threads are completely 'soft' on Linux, * no more per-task TSS's. The TSS size is kept cacheline-aligned * so they are allowed to end up in the .data..cacheline_aligned * section. Since TSS's are completely CPU-local, we want them * on exact cacheline boundaries, to eliminate cacheline ping-pong. */DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS; #ifdef CONFIG_X86_64static DEFINE_PER_CPU(unsigned char, is_idle);static ATOMIC_NOTIFIER_HEAD(idle_notifier); void idle_notifier_register(struct notifier_block *n){	atomic_notifier_chain_register(&idle_notifier, n);}EXPORT_SYMBOL_GPL(idle_notifier_register); void idle_notifier_unregister(struct notifier_block *n){	atomic_notifier_chain_unregister(&idle_notifier, n);}EXPORT_SYMBOL_GPL(idle_notifier_unregister);#endif struct kmem_cache *task_xstate_cachep;EXPORT_SYMBOL_GPL(task_xstate_cachep); /* * this gets called so that we can store lazy state into memory and copy the * current task into the new thread. */int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src){	int ret; 	unlazy_fpu(src); 	*dst = *src;	if (fpu_allocated(&src->thread.fpu)) {		memset(&dst->thread.fpu, 0, sizeof(dst->thread.fpu));		ret = fpu_alloc(&dst->thread.fpu);		if (ret)			return ret;		fpu_copy(&dst->thread.fpu, &src->thread.fpu);	}	return 0;} void free_thread_xstate(struct task_struct *tsk){	fpu_free(&tsk->thread.fpu);} void arch_release_task_struct(struct task_struct *tsk){	free_thread_xstate(tsk);} void arch_task_cache_init(void){        task_xstate_cachep =        	kmem_cache_create("task_xstate", xstate_size,				  __alignof__(union thread_xstate),				  SLAB_PANIC | SLAB_NOTRACK, NULL);} static inline void drop_fpu(struct task_struct *tsk){	/*	 * Forget coprocessor state..	 */	tsk->fpu_counter = 0;	clear_fpu(tsk);	clear_used_math();} /* * Free current thread data structures etc.. */void exit_thread(void){	struct task_struct *me = current;	struct thread_struct *t = &me->thread;	unsigned long *bp = t->io_bitmap_ptr; 	if (bp) {		struct tss_struct *tss = &per_cpu(init_tss, get_cpu()); 		t->io_bitmap_ptr = NULL;		clear_thread_flag(TIF_IO_BITMAP);		/*		 * Careful, clear this in the TSS too:		 */		memset(tss->io_bitmap, 0xff, t->io_bitmap_max);		t->io_bitmap_max = 0;		put_cpu();		kfree(bp);	} 	drop_fpu(me);} void show_regs_common(void){	const char *vendor, *product, *board; 	vendor = dmi_get_system_info(DMI_SYS_VENDOR);	if (!vendor)		vendor = "";	product = dmi_get_system_info(DMI_PRODUCT_NAME);	if (!product)		product = ""; 	/* Board Name is optional */	board = dmi_get_system_info(DMI_BOARD_NAME); 	printk(KERN_CONT "\n");	printk(KERN_DEFAULT "Pid: %d, comm: %.20s %s %s %.*s",		current->pid, current->comm, print_tainted(),		init_utsname()->release,		(int)strcspn(init_utsname()->version, " "),		init_utsname()->version);	printk(KERN_CONT " %s %s", vendor, product);	if (board)		printk(KERN_CONT "/%s", board);	printk(KERN_CONT "\n");} void flush_thread(void){	struct task_struct *tsk = current; 	flush_ptrace_hw_breakpoint(tsk);	memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));	drop_fpu(tsk);} static void hard_disable_TSC(void){	write_cr4(read_cr4() | X86_CR4_TSD);} void disable_TSC(void){	preempt_disable();	if (!test_and_set_thread_flag(TIF_NOTSC))		/*		 * Must flip the CPU state synchronously with		 * TIF_NOTSC in the current running context.		 */		hard_disable_TSC();	preempt_enable();} static void hard_enable_TSC(void){	write_cr4(read_cr4() & ~X86_CR4_TSD);} static void enable_TSC(void){	preempt_disable();	if (test_and_clear_thread_flag(TIF_NOTSC))		/*		 * Must flip the CPU state synchronously with		 * TIF_NOTSC in the current running context.		 */		hard_enable_TSC();	preempt_enable();} int get_tsc_mode(unsigned long adr){	unsigned int val; 	if (test_thread_flag(TIF_NOTSC))		val = PR_TSC_SIGSEGV;	else		val = PR_TSC_ENABLE; 	return put_user(val, (unsigned int __user *)adr);} int set_tsc_mode(unsigned int val){	if (val == PR_TSC_SIGSEGV)		disable_TSC();	else if (val == PR_TSC_ENABLE)		enable_TSC();	else		return -EINVAL; 	return 0;} void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,		      struct tss_struct *tss){	struct thread_struct *prev, *next; 	prev = &prev_p->thread;	next = &next_p->thread; 	if (test_tsk_thread_flag(prev_p, TIF_BLOCKSTEP) ^	    test_tsk_thread_flag(next_p, TIF_BLOCKSTEP)) {		unsigned long debugctl = get_debugctlmsr(); 		debugctl &= ~DEBUGCTLMSR_BTF;		if (test_tsk_thread_flag(next_p, TIF_BLOCKSTEP))			debugctl |= DEBUGCTLMSR_BTF; 		update_debugctlmsr(debugctl);	} 	if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^	    test_tsk_thread_flag(next_p, TIF_NOTSC)) {		/* prev and next are different */		if (test_tsk_thread_flag(next_p, TIF_NOTSC))			hard_disable_TSC();		else			hard_enable_TSC();	} 	if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {		/*		 * Copy the relevant range of the IO bitmap.		 * Normally this is 128 bytes or less:		 */		memcpy(tss->io_bitmap, next->io_bitmap_ptr,		       max(prev->io_bitmap_max, next->io_bitmap_max));	} else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {		/*		 * Clear any possible leftover bits:		 */		memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);	}	propagate_user_return_notify(prev_p, next_p);} int sys_fork(struct pt_regs *regs){	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);} /* * This is trivial, and on the face of it looks like it * could equally well be done in user mode. * * Not so, for quite unobvious reasons - register pressure. * In user mode vfork() cannot have a stack frame, and if * done by calling the "clone()" system call directly, you * do not have enough call-clobbered registers to hold all * the information you need. */int sys_vfork(struct pt_regs *regs){	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,		       NULL, NULL);} longsys_clone(unsigned long clone_flags, unsigned long newsp,	  void __user *parent_tid, void __user *child_tid, struct pt_regs *regs){	if (!newsp)		newsp = regs->sp;	return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);} /* * This gets run with %si containing the * function to call, and %di containing * the "args". */extern void kernel_thread_helper(void); /* * Create a kernel thread */int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags){	struct pt_regs regs; 	memset(&regs, 0, sizeof(regs)); 	regs.si = (unsigned long) fn;	regs.di = (unsigned long) arg; #ifdef CONFIG_X86_32	regs.ds = __USER_DS;	regs.es = __USER_DS;	regs.fs = __KERNEL_PERCPU;	regs.gs = __KERNEL_STACK_CANARY;#else	regs.ss = __KERNEL_DS;#endif 	regs.orig_ax = -1;	regs.ip = (unsigned long) kernel_thread_helper;	regs.cs = __KERNEL_CS | get_kernel_rpl();	regs.flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1; 	/* Ok, create the new process.. */	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);}EXPORT_SYMBOL(kernel_thread); /* * sys_execve() executes a new program. */long sys_execve(const char __user *name,		const char __user *const __user *argv,		const char __user *const __user *envp, struct pt_regs *regs){	long error;	char *filename; 	filename = getname(name);	error = PTR_ERR(filename);	if (IS_ERR(filename))		return error;	error = do_execve(filename, argv, envp, regs); #ifdef CONFIG_X86_32	if (error == 0) {		/* Make sure we don't return using sysenter.. */                set_thread_flag(TIF_IRET);        }#endif 	putname(filename);	return error;} /* * Idle related variables and functions */unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;EXPORT_SYMBOL(boot_option_idle_override); /* * Powermanagement idle function, if any.. */void (*pm_idle)(void);#ifdef CONFIG_APM_MODULEEXPORT_SYMBOL(pm_idle);#endif static inline int hlt_use_halt(void){	return 1;} #ifndef CONFIG_SMPstatic inline void play_dead(void){	BUG();}#endif #ifdef CONFIG_X86_64void enter_idle(void){	this_cpu_write(is_idle, 1);	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);} static void __exit_idle(void){	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)		return;	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);} /* Called from interrupts to signify idle end */void exit_idle(void){	/* idle loop has pid 0 */	if (current->pid)		return;	__exit_idle();}#endif /* * The idle thread. There's no useful work to be * done, so just try to conserve power and have a * low exit latency (ie sit in a loop waiting for * somebody to say that they'd like to reschedule) */void cpu_idle(void){	/*	 * If we're the non-boot CPU, nothing set the stack canary up	 * for us.  CPU0 already has it initialized but no harm in	 * doing it again.  This is a good place for updating it, as	 * we wont ever return from this function (so the invalid	 * canaries already on the stack wont ever trigger).	 */	boot_init_stack_canary();	current_thread_info()->status |= TS_POLLING; 	while (1) {		tick_nohz_idle_enter(); 		while (!need_resched()) {			rmb(); 			if (cpu_is_offline(smp_processor_id()))				play_dead(); 			/*			 * Idle routines should keep interrupts disabled			 * from here on, until they go to idle.			 * Otherwise, idle callbacks can misfire.			 */			local_touch_nmi();			local_irq_disable(); 			enter_idle(); 			/* Don't trace irqs off for idle */			stop_critical_timings(); 			/* enter_idle() needs rcu for notifiers */			rcu_idle_enter(); 			if (cpuidle_idle_call())				pm_idle(); 			rcu_idle_exit();			start_critical_timings(); 			/* In many cases the interrupt that ended idle			   has already called exit_idle. But some idle			   loops can be woken up without interrupt. */			__exit_idle();		} 		tick_nohz_idle_exit();		preempt_enable_no_resched();		schedule();		preempt_disable();	}} /* * We use this if we don't have any better * idle routine.. */void default_idle(void){	if (hlt_use_halt()) {		trace_power_start_rcuidle(POWER_CSTATE, 1, smp_processor_id());		trace_cpu_idle_rcuidle(1, smp_processor_id());		current_thread_info()->status &= ~TS_POLLING;		/*		 * TS_POLLING-cleared state must be visible before we		 * test NEED_RESCHED:		 */		smp_mb(); 		if (!need_resched())			safe_halt();	/* enables interrupts racelessly */		else			local_irq_enable();		current_thread_info()->status |= TS_POLLING;		trace_power_end_rcuidle(smp_processor_id());		trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());

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