// SPDX-License-Identifier: GPL-2.0/* * This file handles the architecture dependent parts of process handling. * *    Copyright IBM Corp. 1999, 2009 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, *		 Hartmut Penner <hp@de.ibm.com>, *		 Denis Joseph Barrow, */ #include <linux/elf-randomize.h>#include <linux/compiler.h>#include <linux/cpu.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/elfcore.h>#include <linux/smp.h>#include <linux/slab.h>#include <linux/interrupt.h>#include <linux/tick.h>#include <linux/personality.h>#include <linux/syscalls.h>#include <linux/compat.h>#include <linux/kprobes.h>#include <linux/random.h>#include <linux/export.h>#include <linux/init_task.h>#include <asm/cpu_mf.h>#include <asm/io.h>#include <asm/processor.h>#include <asm/vtimer.h>#include <asm/exec.h>#include <asm/irq.h>#include <asm/nmi.h>#include <asm/smp.h>#include <asm/stacktrace.h>#include <asm/switch_to.h>#include <asm/runtime_instr.h>#include <asm/unwind.h>#include "entry.h" asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); extern void kernel_thread_starter(void); void flush_thread(void){} void arch_setup_new_exec(void){	if (S390_lowcore.current_pid != current->pid) {		S390_lowcore.current_pid = current->pid;		if (test_facility(40))			lpp(&S390_lowcore.lpp);	}} void arch_release_task_struct(struct task_struct *tsk){	runtime_instr_release(tsk);	guarded_storage_release(tsk);} int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src){	/*	 * Save the floating-point or vector register state of the current	 * task and set the CIF_FPU flag to lazy restore the FPU register	 * state when returning to user space.	 */	save_fpu_regs(); 	memcpy(dst, src, arch_task_struct_size);	dst->thread.fpu.regs = dst->thread.fpu.fprs;	return 0;} int copy_thread(unsigned long clone_flags, unsigned long new_stackp,		unsigned long arg, struct task_struct *p, unsigned long tls){	struct fake_frame	{		struct stack_frame sf;		struct pt_regs childregs;	} *frame; 	frame = container_of(task_pt_regs(p), struct fake_frame, childregs);	p->thread.ksp = (unsigned long) frame;	/* Save access registers to new thread structure. */	save_access_regs(&p->thread.acrs[0]);	/* start new process with ar4 pointing to the correct address space */	p->thread.mm_segment = get_fs();	/* Don't copy debug registers */	memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));	memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));	clear_tsk_thread_flag(p, TIF_SINGLE_STEP);	p->thread.per_flags = 0;	/* Initialize per thread user and system timer values */	p->thread.user_timer = 0;	p->thread.guest_timer = 0;	p->thread.system_timer = 0;	p->thread.hardirq_timer = 0;	p->thread.softirq_timer = 0;	p->thread.last_break = 1; 	frame->sf.back_chain = 0;	/* new return point is ret_from_fork */	frame->sf.gprs[8] = (unsigned long) ret_from_fork;	/* fake return stack for resume(), don't go back to schedule */	frame->sf.gprs[9] = (unsigned long) frame; 	/* Store access registers to kernel stack of new process. */	if (unlikely(p->flags & PF_KTHREAD)) {		/* kernel thread */		memset(&frame->childregs, 0, sizeof(struct pt_regs));		frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |				PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;		frame->childregs.psw.addr =				(unsigned long) kernel_thread_starter;		frame->childregs.gprs[9] = new_stackp; /* function */		frame->childregs.gprs[10] = arg;		frame->childregs.gprs[11] = (unsigned long) do_exit;		frame->childregs.orig_gpr2 = -1; 		return 0;	}	frame->childregs = *current_pt_regs();	frame->childregs.gprs[2] = 0;	/* child returns 0 on fork. */	frame->childregs.flags = 0;	if (new_stackp)		frame->childregs.gprs[15] = new_stackp; 	/* Don't copy runtime instrumentation info */	p->thread.ri_cb = NULL;	frame->childregs.psw.mask &= ~PSW_MASK_RI;	/* Don't copy guarded storage control block */	p->thread.gs_cb = NULL;	p->thread.gs_bc_cb = NULL; 	/* Set a new TLS ?  */	if (clone_flags & CLONE_SETTLS) {		if (is_compat_task()) {			p->thread.acrs[0] = (unsigned int)tls;		} else {			p->thread.acrs[0] = (unsigned int)(tls >> 32);			p->thread.acrs[1] = (unsigned int)tls;		}	}	return 0;} asmlinkage void execve_tail(void){	current->thread.fpu.fpc = 0;	asm volatile("sfpc %0" : : "d" (0));} unsigned long get_wchan(struct task_struct *p){	struct unwind_state state;	unsigned long ip = 0; 	if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))		return 0; 	if (!try_get_task_stack(p))		return 0; 	unwind_for_each_frame(&state, p, NULL, 0) {		if (state.stack_info.type != STACK_TYPE_TASK) {			ip = 0;			break;		} 		ip = unwind_get_return_address(&state);		if (!ip)			break; 		if (!in_sched_functions(ip))			break;	} 	put_task_stack(p);	return ip;} unsigned long arch_align_stack(unsigned long sp){	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)		sp -= get_random_int() & ~PAGE_MASK;	return sp & ~0xf;} static inline unsigned long brk_rnd(void){	return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;} unsigned long arch_randomize_brk(struct mm_struct *mm){	unsigned long ret; 	ret = PAGE_ALIGN(mm->brk + brk_rnd());	return (ret > mm->brk) ? ret : mm->brk;} void set_fs_fixup(void){	struct pt_regs *regs = current_pt_regs();	static bool warned; 	set_fs(USER_DS);	if (warned)		return;	WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);	show_registers(regs);	warned = true;}