/* * 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/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/switch_to.h>#include <asm/runtime_instr.h>#include "entry.h" asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); extern void kernel_thread_starter(void); /* * Free current thread data structures etc.. */void exit_thread(struct task_struct *tsk){	if (tsk == current) {		exit_thread_runtime_instr();		exit_thread_gs();	}} void flush_thread(void){} void release_thread(struct task_struct *dead_task){} void arch_release_task_struct(struct task_struct *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_tls(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);	/* 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; 	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));} /* * fill in the FPU structure for a core dump. */int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs){	save_fpu_regs();	fpregs->fpc = current->thread.fpu.fpc;	fpregs->pad = 0;	if (MACHINE_HAS_VX)		convert_vx_to_fp((freg_t *)&fpregs->fprs,				 current->thread.fpu.vxrs);	else		memcpy(&fpregs->fprs, current->thread.fpu.fprs,		       sizeof(fpregs->fprs));	return 1;}EXPORT_SYMBOL(dump_fpu); unsigned long get_wchan(struct task_struct *p){	struct stack_frame *sf, *low, *high;	unsigned long return_address;	int count; 	if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))		return 0;	low = task_stack_page(p);	high = (struct stack_frame *) task_pt_regs(p);	sf = (struct stack_frame *) p->thread.ksp;	if (sf <= low || sf > high)		return 0;	for (count = 0; count < 16; count++) {		sf = (struct stack_frame *) sf->back_chain;		if (sf <= low || sf > high)			return 0;		return_address = sf->gprs[8];		if (!in_sched_functions(return_address))			return return_address;	}	return 0;} 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;}