// SPDX-License-Identifier: GPL-2.0/* * Author: Huacai Chen <chenhuacai@loongson.cn> * Copyright (C) 2020-2022 Loongson Technology Corporation Limited * * Derived from MIPS: * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others. * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org) * Copyright (C) 1999, 2000 Silicon Graphics, Inc. * Copyright (C) 2004 Thiemo Seufer * Copyright (C) 2013  Imagination Technologies Ltd. */#include <linux/cpu.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/entry-common.h>#include <linux/errno.h>#include <linux/sched.h>#include <linux/sched/debug.h>#include <linux/sched/task.h>#include <linux/sched/task_stack.h>#include <linux/hw_breakpoint.h>#include <linux/mm.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/export.h>#include <linux/ptrace.h>#include <linux/mman.h>#include <linux/personality.h>#include <linux/sys.h>#include <linux/completion.h>#include <linux/kallsyms.h>#include <linux/random.h>#include <linux/prctl.h>#include <linux/nmi.h> #include <asm/asm.h>#include <asm/asm-prototypes.h>#include <asm/bootinfo.h>#include <asm/cpu.h>#include <asm/elf.h>#include <asm/exec.h>#include <asm/fpu.h>#include <asm/lbt.h>#include <asm/io.h>#include <asm/irq.h>#include <asm/irq_regs.h>#include <asm/loongarch.h>#include <asm/pgtable.h>#include <asm/processor.h>#include <asm/reg.h>#include <asm/switch_to.h>#include <asm/unwind.h>#include <asm/vdso.h>#include <asm/vdso/vdso.h> #ifdef CONFIG_STACKPROTECTOR#include <linux/stackprotector.h>unsigned long __stack_chk_guard __read_mostly;EXPORT_SYMBOL(__stack_chk_guard);#endif DEFINE_PER_CPU(struct task_struct *, cpu_tasks); /* * Idle related variables and functions */ unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;EXPORT_SYMBOL(boot_option_idle_override); asmlinkage void restore_and_ret(void);asmlinkage void ret_from_fork_asm(void);asmlinkage void ret_from_kernel_thread_asm(void); void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp){	unsigned long crmd;	unsigned long prmd;	unsigned long euen; 	/* New thread loses kernel privileges. */	crmd = regs->csr_crmd & ~(PLV_MASK);	crmd |= PLV_USER;	regs->csr_crmd = crmd; 	prmd = regs->csr_prmd & ~(PLV_MASK);	prmd |= PLV_USER;	regs->csr_prmd = prmd; 	euen = regs->csr_euen & ~(CSR_EUEN_FPEN);	regs->csr_euen = euen;	lose_fpu(0);	lose_lbt(0);	current->thread.fpu.fcsr = boot_cpu_data.fpu_csr0; 	clear_thread_flag(TIF_LSX_CTX_LIVE);	clear_thread_flag(TIF_LASX_CTX_LIVE);	clear_thread_flag(TIF_LBT_CTX_LIVE);	clear_used_math();	regs->csr_era = pc;	regs->regs[3] = sp;} void flush_thread(void){	flush_ptrace_hw_breakpoint(current);} void exit_thread(struct task_struct *tsk){} int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src){	/*	 * Save any process state which is live in hardware registers to the	 * parent context prior to duplication. This prevents the new child	 * state becoming stale if the parent is preempted before copy_thread()	 * gets a chance to save the parent's live hardware registers to the	 * child context.	 */	preempt_disable(); 	if (is_fpu_owner()) {		if (is_lasx_enabled())			save_lasx(current);		else if (is_lsx_enabled())			save_lsx(current);		else			save_fp(current);	} 	preempt_enable(); 	if (IS_ENABLED(CONFIG_RANDSTRUCT)) {		memcpy(dst, src, sizeof(struct task_struct));		return 0;	} 	dst->thread.fpu.fcsr =  src->thread.fpu.fcsr; 	if (!used_math())		memcpy(dst, src, offsetof(struct task_struct, thread.fpu.fpr));	else		memcpy(dst, src, offsetof(struct task_struct, thread.lbt.scr0)); #ifdef CONFIG_CPU_HAS_LBT	memcpy(&dst->thread.lbt, &src->thread.lbt, sizeof(struct loongarch_lbt));#endif 	return 0;} asmlinkage void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev,							   struct pt_regs *regs){	schedule_tail(prev);	syscall_exit_to_user_mode(regs);} asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev,								    struct pt_regs *regs,								    int (*fn)(void *),								    void *fn_arg){	schedule_tail(prev);	fn(fn_arg);	syscall_exit_to_user_mode(regs);} /* * Copy architecture-specific thread state */int copy_thread(struct task_struct *p, const struct kernel_clone_args *args){	unsigned long childksp;	unsigned long tls = args->tls;	unsigned long usp = args->stack;	u64 clone_flags = args->flags;	struct pt_regs *childregs, *regs = current_pt_regs(); 	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE; 	/* set up new TSS. */	childregs = (struct pt_regs *) childksp - 1;	/*  Put the stack after the struct pt_regs.  */	childksp = (unsigned long) childregs;	p->thread.sched_cfa = 0;	p->thread.csr_euen = 0;	p->thread.csr_crmd = csr_read32(LOONGARCH_CSR_CRMD);	p->thread.csr_prmd = csr_read32(LOONGARCH_CSR_PRMD);	p->thread.csr_ecfg = csr_read32(LOONGARCH_CSR_ECFG);	if (unlikely(args->fn)) {		/* kernel thread */		p->thread.reg03 = childksp;		p->thread.reg23 = (unsigned long)args->fn;		p->thread.reg24 = (unsigned long)args->fn_arg;		p->thread.reg01 = (unsigned long)ret_from_kernel_thread_asm;		p->thread.sched_ra = (unsigned long)ret_from_kernel_thread_asm;		memset(childregs, 0, sizeof(struct pt_regs));		childregs->csr_euen = p->thread.csr_euen;		childregs->csr_crmd = p->thread.csr_crmd;		childregs->csr_prmd = p->thread.csr_prmd;		childregs->csr_ecfg = p->thread.csr_ecfg;		goto out;	} 	/* user thread */	*childregs = *regs;	childregs->regs[4] = 0; /* Child gets zero as return value */	if (usp)		childregs->regs[3] = usp; 	p->thread.reg03 = (unsigned long) childregs;	p->thread.reg01 = (unsigned long) ret_from_fork_asm;	p->thread.sched_ra = (unsigned long) ret_from_fork_asm; 	/*	 * New tasks lose permission to use the fpu. This accelerates context	 * switching for most programs since they don't use the fpu.	 */	childregs->csr_euen = 0; 	if (clone_flags & CLONE_SETTLS)		childregs->regs[2] = tls; out:	ptrace_hw_copy_thread(p);	clear_tsk_thread_flag(p, TIF_USEDFPU);	clear_tsk_thread_flag(p, TIF_USEDSIMD);	clear_tsk_thread_flag(p, TIF_USEDLBT);	clear_tsk_thread_flag(p, TIF_LSX_CTX_LIVE);	clear_tsk_thread_flag(p, TIF_LASX_CTX_LIVE);	clear_tsk_thread_flag(p, TIF_LBT_CTX_LIVE); 	return 0;} unsigned long __get_wchan(struct task_struct *task){	unsigned long pc = 0;	struct unwind_state state; 	if (!try_get_task_stack(task))		return 0; 	for (unwind_start(&state, task, NULL);	     !unwind_done(&state); unwind_next_frame(&state)) {		pc = unwind_get_return_address(&state);		if (!pc)			break;		if (in_sched_functions(pc))			continue;		break;	} 	put_task_stack(task); 	return pc;} bool in_irq_stack(unsigned long stack, struct stack_info *info){	unsigned long nextsp;	unsigned long begin = (unsigned long)this_cpu_read(irq_stack);	unsigned long end = begin + IRQ_STACK_START; 	if (stack < begin || stack >= end)		return false; 	nextsp = *(unsigned long *)end;	if (nextsp & (SZREG - 1))		return false; 	info->begin = begin;	info->end = end;	info->next_sp = nextsp;	info->type = STACK_TYPE_IRQ; 	return true;} bool in_task_stack(unsigned long stack, struct task_struct *task,			struct stack_info *info){	unsigned long begin = (unsigned long)task_stack_page(task);	unsigned long end = begin + THREAD_SIZE; 	if (stack < begin || stack >= end)		return false; 	info->begin = begin;	info->end = end;	info->next_sp = 0;	info->type = STACK_TYPE_TASK; 	return true;} int get_stack_info(unsigned long stack, struct task_struct *task,		   struct stack_info *info){	task = task ? : current; 	if (!stack || stack & (SZREG - 1))		goto unknown; 	if (in_task_stack(stack, task, info))		return 0; 	if (task != current)		goto unknown; 	if (in_irq_stack(stack, info))		return 0; unknown:	info->type = STACK_TYPE_UNKNOWN;	return -EINVAL;} unsigned long stack_top(void){	unsigned long top = TASK_SIZE & PAGE_MASK; 	if (current->thread.vdso) {		/* Space for the VDSO & data page */		top -= PAGE_ALIGN(current->thread.vdso->size);		top -= VVAR_SIZE; 		/* Space to randomize the VDSO base */		if (current->flags & PF_RANDOMIZE)			top -= VDSO_RANDOMIZE_SIZE;	} 	return top;} /* * Don't forget that the stack pointer must be aligned on a 8 bytes * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. */unsigned long arch_align_stack(unsigned long sp){	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)		sp -= get_random_u32_below(PAGE_SIZE); 	return sp & STACK_ALIGN;} static DEFINE_PER_CPU(call_single_data_t, backtrace_csd);static struct cpumask backtrace_csd_busy; static void handle_backtrace(void *info){	nmi_cpu_backtrace(get_irq_regs());	cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);} static void raise_backtrace(cpumask_t *mask){	call_single_data_t *csd;	int cpu; 	for_each_cpu(cpu, mask) {		/*		 * If we previously sent an IPI to the target CPU & it hasn't		 * cleared its bit in the busy cpumask then it didn't handle		 * our previous IPI & it's not safe for us to reuse the		 * call_single_data_t.		 */		if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {			pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",				cpu);			continue;		} 		csd = &per_cpu(backtrace_csd, cpu);		csd->func = handle_backtrace;		smp_call_function_single_async(cpu, csd);	}} void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu){	nmi_trigger_cpumask_backtrace(mask, exclude_cpu, raise_backtrace);} #ifdef CONFIG_32BITvoid loongarch_dump_regs32(u32 *uregs, const struct pt_regs *regs)#elsevoid loongarch_dump_regs64(u64 *uregs, const struct pt_regs *regs)#endif{	unsigned int i; 	for (i = LOONGARCH_EF_R1; i <= LOONGARCH_EF_R31; i++) {		uregs[i] = regs->regs[i - LOONGARCH_EF_R0];	} 	uregs[LOONGARCH_EF_ORIG_A0] = regs->orig_a0;	uregs[LOONGARCH_EF_CSR_ERA] = regs->csr_era;	uregs[LOONGARCH_EF_CSR_BADV] = regs->csr_badvaddr;	uregs[LOONGARCH_EF_CSR_CRMD] = regs->csr_crmd;	uregs[LOONGARCH_EF_CSR_PRMD] = regs->csr_prmd;	uregs[LOONGARCH_EF_CSR_EUEN] = regs->csr_euen;	uregs[LOONGARCH_EF_CSR_ECFG] = regs->csr_ecfg;	uregs[LOONGARCH_EF_CSR_ESTAT] = regs->csr_estat;}