// SPDX-License-Identifier: GPL-2.0-only/* *  linux/arch/arm/kernel/process.c * *  Copyright (C) 1996-2000 Russell King - Converted to ARM. *  Original Copyright (C) 1995  Linus Torvalds */#include <linux/export.h>#include <linux/sched.h>#include <linux/sched/debug.h>#include <linux/sched/task.h>#include <linux/sched/task_stack.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/user.h>#include <linux/interrupt.h>#include <linux/init.h>#include <linux/elfcore.h>#include <linux/pm.h>#include <linux/tick.h>#include <linux/utsname.h>#include <linux/uaccess.h>#include <linux/random.h>#include <linux/hw_breakpoint.h>#include <linux/leds.h> #include <asm/processor.h>#include <asm/thread_notify.h>#include <asm/stacktrace.h>#include <asm/system_misc.h>#include <asm/mach/time.h>#include <asm/tls.h>#include <asm/vdso.h> #include "signal.h" #if defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)DEFINE_PER_CPU(struct task_struct *, __entry_task);#endif #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)#include <linux/stackprotector.h>unsigned long __stack_chk_guard __read_mostly;EXPORT_SYMBOL(__stack_chk_guard);#endif #ifndef CONFIG_CURRENT_POINTER_IN_TPIDRUROasmlinkage struct task_struct *__current;EXPORT_SYMBOL(__current);#endif static const char *processor_modes[] __maybe_unused = {  "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,  "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",  "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,  "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"}; static const char *isa_modes[] __maybe_unused = {  "ARM" , "Thumb" , "Jazelle", "ThumbEE"}; /* * This is our default idle handler. */ void (*arm_pm_idle)(void); /* * Called from the core idle loop. */ void arch_cpu_idle(void){	if (arm_pm_idle)		arm_pm_idle();	else		cpu_do_idle();	raw_local_irq_enable();} void arch_cpu_idle_prepare(void){	local_fiq_enable();} void arch_cpu_idle_enter(void){	ledtrig_cpu(CPU_LED_IDLE_START);#ifdef CONFIG_PL310_ERRATA_769419	wmb();#endif} void arch_cpu_idle_exit(void){	ledtrig_cpu(CPU_LED_IDLE_END);} void __show_regs_alloc_free(struct pt_regs *regs){	int i; 	/* check for r0 - r12 only */	for (i = 0; i < 13; i++) {		pr_alert("Register r%d information:", i);		mem_dump_obj((void *)regs->uregs[i]);	}} void __show_regs(struct pt_regs *regs){	unsigned long flags;	char buf[64];#ifndef CONFIG_CPU_V7M	unsigned int domain;#ifdef CONFIG_CPU_SW_DOMAIN_PAN	/*	 * Get the domain register for the parent context. In user	 * mode, we don't save the DACR, so lets use what it should	 * be. For other modes, we place it after the pt_regs struct.	 */	if (user_mode(regs)) {		domain = DACR_UACCESS_ENABLE;	} else {		domain = to_svc_pt_regs(regs)->dacr;	}#else	domain = get_domain();#endif#endif 	show_regs_print_info(KERN_DEFAULT); 	printk("PC is at %pS\n", (void *)instruction_pointer(regs));	printk("LR is at %pS\n", (void *)regs->ARM_lr);	printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n",	       regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);	printk("sp : %08lx  ip : %08lx  fp : %08lx\n",	       regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);	printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",		regs->ARM_r10, regs->ARM_r9,		regs->ARM_r8);	printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",		regs->ARM_r7, regs->ARM_r6,		regs->ARM_r5, regs->ARM_r4);	printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",		regs->ARM_r3, regs->ARM_r2,		regs->ARM_r1, regs->ARM_r0); 	flags = regs->ARM_cpsr;	buf[0] = flags & PSR_N_BIT ? 'N' : 'n';	buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';	buf[2] = flags & PSR_C_BIT ? 'C' : 'c';	buf[3] = flags & PSR_V_BIT ? 'V' : 'v';	buf[4] = '\0'; #ifndef CONFIG_CPU_V7M	{		const char *segment; 		if ((domain & domain_mask(DOMAIN_USER)) ==		    domain_val(DOMAIN_USER, DOMAIN_NOACCESS))			segment = "none";		else			segment = "user"; 		printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",			buf, interrupts_enabled(regs) ? "n" : "ff",			fast_interrupts_enabled(regs) ? "n" : "ff",			processor_modes[processor_mode(regs)],			isa_modes[isa_mode(regs)], segment);	}#else	printk("xPSR: %08lx\n", regs->ARM_cpsr);#endif #ifdef CONFIG_CPU_CP15	{		unsigned int ctrl; 		buf[0] = '\0';#ifdef CONFIG_CPU_CP15_MMU		{			unsigned int transbase;			asm("mrc p15, 0, %0, c2, c0\n\t"			    : "=r" (transbase));			snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",				transbase, domain);		}#endif		asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 		printk("Control: %08x%s\n", ctrl, buf);	}#endif} void show_regs(struct pt_regs * regs){	__show_regs(regs);	dump_stack();} ATOMIC_NOTIFIER_HEAD(thread_notify_head); EXPORT_SYMBOL_GPL(thread_notify_head); /* * Free current thread data structures etc.. */void exit_thread(struct task_struct *tsk){	thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));} void flush_thread(void){	struct thread_info *thread = current_thread_info();	struct task_struct *tsk = current; 	flush_ptrace_hw_breakpoint(tsk); 	memset(thread->used_cp, 0, sizeof(thread->used_cp));	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));	memset(&thread->fpstate, 0, sizeof(union fp_state)); 	flush_tls(); 	thread_notify(THREAD_NOTIFY_FLUSH, thread);} void release_thread(struct task_struct *dead_task){} asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); int copy_thread(struct task_struct *p, const struct kernel_clone_args *args){	unsigned long clone_flags = args->flags;	unsigned long stack_start = args->stack;	unsigned long tls = args->tls;	struct thread_info *thread = task_thread_info(p);	struct pt_regs *childregs = task_pt_regs(p); 	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); #ifdef CONFIG_CPU_USE_DOMAINS	/*	 * Copy the initial value of the domain access control register	 * from the current thread: thread->addr_limit will have been	 * copied from the current thread via setup_thread_stack() in	 * kernel/fork.c	 */	thread->cpu_domain = get_domain();#endif 	if (likely(!args->fn)) {		*childregs = *current_pt_regs();		childregs->ARM_r0 = 0;		if (stack_start)			childregs->ARM_sp = stack_start;	} else {		memset(childregs, 0, sizeof(struct pt_regs));		thread->cpu_context.r4 = (unsigned long)args->fn_arg;		thread->cpu_context.r5 = (unsigned long)args->fn;		childregs->ARM_cpsr = SVC_MODE;	}	thread->cpu_context.pc = (unsigned long)ret_from_fork;	thread->cpu_context.sp = (unsigned long)childregs; 	clear_ptrace_hw_breakpoint(p); 	if (clone_flags & CLONE_SETTLS)		thread->tp_value[0] = tls;	thread->tp_value[1] = get_tpuser(); 	thread_notify(THREAD_NOTIFY_COPY, thread); 	return 0;} unsigned long __get_wchan(struct task_struct *p){	struct stackframe frame;	unsigned long stack_page;	int count = 0; 	frame.fp = thread_saved_fp(p);	frame.sp = thread_saved_sp(p);	frame.lr = 0;			/* recovered from the stack */	frame.pc = thread_saved_pc(p);	stack_page = (unsigned long)task_stack_page(p);	do {		if (frame.sp < stack_page ||		    frame.sp >= stack_page + THREAD_SIZE ||		    unwind_frame(&frame) < 0)			return 0;		if (!in_sched_functions(frame.pc))			return frame.pc;	} while (count ++ < 16);	return 0;} #ifdef CONFIG_MMU#ifdef CONFIG_KUSER_HELPERS/* * The vectors page is always readable from user space for the * atomic helpers. Insert it into the gate_vma so that it is visible * through ptrace and /proc/<pid>/mem. */static struct vm_area_struct gate_vma; static int __init gate_vma_init(void){	vma_init(&gate_vma, NULL);	gate_vma.vm_page_prot = PAGE_READONLY_EXEC;	gate_vma.vm_start = 0xffff0000;	gate_vma.vm_end	= 0xffff0000 + PAGE_SIZE;	gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;	return 0;}arch_initcall(gate_vma_init); struct vm_area_struct *get_gate_vma(struct mm_struct *mm){	return &gate_vma;} int in_gate_area(struct mm_struct *mm, unsigned long addr){	return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);} int in_gate_area_no_mm(unsigned long addr){	return in_gate_area(NULL, addr);}#define is_gate_vma(vma)	((vma) == &gate_vma)#else#define is_gate_vma(vma)	0#endif const char *arch_vma_name(struct vm_area_struct *vma){	return is_gate_vma(vma) ? "[vectors]" : NULL;} /* If possible, provide a placement hint at a random offset from the * stack for the sigpage and vdso pages. */static unsigned long sigpage_addr(const struct mm_struct *mm,				  unsigned int npages){	unsigned long offset;	unsigned long first;	unsigned long last;	unsigned long addr;	unsigned int slots; 	first = PAGE_ALIGN(mm->start_stack); 	last = TASK_SIZE - (npages << PAGE_SHIFT); 	/* No room after stack? */	if (first > last)		return 0; 	/* Just enough room? */	if (first == last)		return first; 	slots = ((last - first) >> PAGE_SHIFT) + 1; 	offset = get_random_int() % slots; 	addr = first + (offset << PAGE_SHIFT); 	return addr;} static struct page *signal_page;extern struct page *get_signal_page(void); static int sigpage_mremap(const struct vm_special_mapping *sm,		struct vm_area_struct *new_vma){	current->mm->context.sigpage = new_vma->vm_start;	return 0;} static const struct vm_special_mapping sigpage_mapping = {	.name = "[sigpage]",	.pages = &signal_page,	.mremap = sigpage_mremap,}; int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp){	struct mm_struct *mm = current->mm;	struct vm_area_struct *vma;	unsigned long npages;	unsigned long addr;	unsigned long hint;	int ret = 0; 	if (!signal_page)		signal_page = get_signal_page();	if (!signal_page)		return -ENOMEM; 	npages = 1; /* for sigpage */	npages += vdso_total_pages; 	if (mmap_write_lock_killable(mm))		return -EINTR;	hint = sigpage_addr(mm, npages);	addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);	if (IS_ERR_VALUE(addr)) {		ret = addr;		goto up_fail;	} 	vma = _install_special_mapping(mm, addr, PAGE_SIZE,		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,		&sigpage_mapping); 	if (IS_ERR(vma)) {		ret = PTR_ERR(vma);		goto up_fail;	} 	mm->context.sigpage = addr; 	/* Unlike the sigpage, failure to install the vdso is unlikely	 * to be fatal to the process, so no error check needed	 * here.	 */	arm_install_vdso(mm, addr + PAGE_SIZE);  up_fail:	mmap_write_unlock(mm);	return ret;}#endif