/* * 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/compiler.h>#include <linux/cpu.h>#include <linux/sched.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/module.h>#include <asm/io.h>#include <asm/processor.h>#include <asm/irq.h>#include <asm/timer.h>#include <asm/nmi.h>#include <asm/smp.h>#include <asm/switch_to.h>#include "entry.h" asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); /* * Return saved PC of a blocked thread. used in kernel/sched. * resume in entry.S does not create a new stack frame, it * just stores the registers %r6-%r15 to the frame given by * schedule. We want to return the address of the caller of * schedule, so we have to walk the backchain one time to * find the frame schedule() store its return address. */unsigned long thread_saved_pc(struct task_struct *tsk){	struct stack_frame *sf, *low, *high; 	if (!tsk || !task_stack_page(tsk))		return 0;	low = task_stack_page(tsk);	high = (struct stack_frame *) task_pt_regs(tsk);	sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);	if (sf <= low || sf > high)		return 0;	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);	if (sf <= low || sf > high)		return 0;	return sf->gprs[8];} /* * The idle loop on a S390... */static void default_idle(void){	if (cpu_is_offline(smp_processor_id()))		cpu_die();	local_irq_disable();	if (need_resched()) {		local_irq_enable();		return;	}	local_mcck_disable();	if (test_thread_flag(TIF_MCCK_PENDING)) {		local_mcck_enable();		local_irq_enable();		return;	}	/* Halt the cpu and keep track of cpu time accounting. */	vtime_stop_cpu();} void cpu_idle(void){	for (;;) {		tick_nohz_idle_enter();		rcu_idle_enter();		while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING))			default_idle();		rcu_idle_exit();		tick_nohz_idle_exit();		if (test_thread_flag(TIF_MCCK_PENDING))			s390_handle_mcck();		schedule_preempt_disabled();	}} extern void __kprobes kernel_thread_starter(void); asm(	".section .kprobes.text, \"ax\"\n"	".global kernel_thread_starter\n"	"kernel_thread_starter:\n"	"    la    2,0(10)\n"	"    basr  14,9\n"	"    la    2,0\n"	"    br    11\n"	".previous\n"); int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags){	struct pt_regs regs; 	memset(&regs, 0, sizeof(regs));	regs.psw.mask = psw_kernel_bits |		PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;	regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;	regs.gprs[9] = (unsigned long) fn;	regs.gprs[10] = (unsigned long) arg;	regs.gprs[11] = (unsigned long) do_exit;	regs.orig_gpr2 = -1; 	/* Ok, create the new process.. */	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,		       0, &regs, 0, NULL, NULL);}EXPORT_SYMBOL(kernel_thread); /* * Free current thread data structures etc.. */void exit_thread(void){} void flush_thread(void){} void release_thread(struct task_struct *dead_task){} int copy_thread(unsigned long clone_flags, unsigned long new_stackp,		unsigned long unused,		struct task_struct *p, struct pt_regs *regs){	struct thread_info *ti;	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;	/* Store access registers to kernel stack of new process. */	frame->childregs = *regs;	frame->childregs.gprs[2] = 0;	/* child returns 0 on fork. */	frame->childregs.gprs[15] = new_stackp;	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; 	/* Save access registers to new thread structure. */	save_access_regs(&p->thread.acrs[0]); #ifndef CONFIG_64BIT	/*	 * save fprs to current->thread.fp_regs to merge them with	 * the emulated registers and then copy the result to the child.	 */	save_fp_regs(&current->thread.fp_regs);	memcpy(&p->thread.fp_regs, &current->thread.fp_regs,	       sizeof(s390_fp_regs));	/* Set a new TLS ?  */	if (clone_flags & CLONE_SETTLS)		p->thread.acrs[0] = regs->gprs[6];#else /* CONFIG_64BIT */	/* Save the fpu registers to new thread structure. */	save_fp_regs(&p->thread.fp_regs);	/* Set a new TLS ?  */	if (clone_flags & CLONE_SETTLS) {		if (is_compat_task()) {			p->thread.acrs[0] = (unsigned int) regs->gprs[6];		} else {			p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);			p->thread.acrs[1] = (unsigned int) regs->gprs[6];		}	}#endif /* CONFIG_64BIT */	/* 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);	clear_tsk_thread_flag(p, TIF_PER_TRAP);	/* Initialize per thread user and system timer values */	ti = task_thread_info(p);	ti->user_timer = 0;	ti->system_timer = 0;	return 0;} SYSCALL_DEFINE0(fork){	struct pt_regs *regs = task_pt_regs(current);	return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);} SYSCALL_DEFINE4(clone, unsigned long, newsp, unsigned long, clone_flags,		int __user *, parent_tidptr, int __user *, child_tidptr){	struct pt_regs *regs = task_pt_regs(current); 	if (!newsp)		newsp = regs->gprs[15];	return do_fork(clone_flags, newsp, regs, 0,		       parent_tidptr, child_tidptr);} /* * 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. */SYSCALL_DEFINE0(vfork){	struct pt_regs *regs = task_pt_regs(current);	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,		       regs->gprs[15], regs, 0, NULL, NULL);} asmlinkage void execve_tail(void){	current->thread.fp_regs.fpc = 0;	if (MACHINE_HAS_IEEE)		asm volatile("sfpc %0,%0" : : "d" (0));} /* * sys_execve() executes a new program. */SYSCALL_DEFINE3(execve, const char __user *, name,		const char __user *const __user *, argv,		const char __user *const __user *, envp){	struct pt_regs *regs = task_pt_regs(current);	char *filename;	long rc; 	filename = getname(name);	rc = PTR_ERR(filename);	if (IS_ERR(filename))		return rc;	rc = do_execve(filename, argv, envp, regs);	if (rc)		goto out;	execve_tail();	rc = regs->gprs[2];out:	putname(filename);	return rc;} /* * fill in the FPU structure for a core dump. */int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs){#ifndef CONFIG_64BIT	/*	 * save fprs to current->thread.fp_regs to merge them with	 * the emulated registers and then copy the result to the dump.	 */	save_fp_regs(&current->thread.fp_regs);	memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));#else /* CONFIG_64BIT */	save_fp_regs(fpregs);#endif /* CONFIG_64BIT */	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 & PSW_ADDR_INSN);	if (sf <= low || sf > high)		return 0;	for (count = 0; count < 16; count++) {		sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);		if (sf <= low || sf > high)			return 0;		return_address = sf->gprs[8] & PSW_ADDR_INSN;		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){	/* 8MB for 32bit, 1GB for 64bit */	if (is_32bit_task())		return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;	else		return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;} unsigned long arch_randomize_brk(struct mm_struct *mm){	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd()); 	if (ret < mm->brk)		return mm->brk;	return ret;} unsigned long randomize_et_dyn(unsigned long base){	unsigned long ret = PAGE_ALIGN(base + brk_rnd()); 	if (!(current->flags & PF_RANDOMIZE))		return base;	if (ret < base)		return base;	return ret;}