/* *  arch/s390/kernel/process.c * *  S390 version *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), *               Hartmut Penner (hp@de.ibm.com), *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com), * *  Derived from "arch/i386/kernel/process.c" *    Copyright (C) 1995, Linus Torvalds */ /* * This file handles the architecture-dependent parts of process handling.. */ #include <linux/compiler.h>#include <linux/cpu.h>#include <linux/errno.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/smp.h>#include <linux/smp_lock.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/ptrace.h>#include <linux/slab.h>#include <linux/vmalloc.h>#include <linux/user.h>#include <linux/a.out.h>#include <linux/interrupt.h>#include <linux/delay.h>#include <linux/reboot.h>#include <linux/init.h>#include <linux/module.h>#include <linux/notifier.h> #include <asm/uaccess.h>#include <asm/pgtable.h>#include <asm/system.h>#include <asm/io.h>#include <asm/processor.h>#include <asm/irq.h>#include <asm/timer.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];} /* * Need to know about CPUs going idle? */static ATOMIC_NOTIFIER_HEAD(idle_chain); int register_idle_notifier(struct notifier_block *nb){	return atomic_notifier_chain_register(&idle_chain, nb);}EXPORT_SYMBOL(register_idle_notifier); int unregister_idle_notifier(struct notifier_block *nb){	return atomic_notifier_chain_unregister(&idle_chain, nb);}EXPORT_SYMBOL(unregister_idle_notifier); void do_monitor_call(struct pt_regs *regs, long interruption_code){	/* disable monitor call class 0 */	__ctl_clear_bit(8, 15); 	atomic_notifier_call_chain(&idle_chain, CPU_NOT_IDLE,			    (void *)(long) smp_processor_id());} extern void s390_handle_mcck(void);/* * The idle loop on a S390... */static void default_idle(void){	int cpu, rc; 	/* CPU is going idle. */	cpu = smp_processor_id(); 	local_irq_disable();	if (need_resched()) {		local_irq_enable();		return;	} 	rc = atomic_notifier_call_chain(&idle_chain,			CPU_IDLE, (void *)(long) cpu);	if (rc != NOTIFY_OK && rc != NOTIFY_DONE)		BUG();	if (rc != NOTIFY_OK) {		local_irq_enable();		return;	} 	/* enable monitor call class 0 */	__ctl_set_bit(8, 15); #ifdef CONFIG_HOTPLUG_CPU	if (cpu_is_offline(cpu)) {		preempt_enable_no_resched();		cpu_die();	}#endif 	local_mcck_disable();	if (test_thread_flag(TIF_MCCK_PENDING)) {		local_mcck_enable();		local_irq_enable();		s390_handle_mcck();		return;	} 	trace_hardirqs_on();	/* Wait for external, I/O or machine check interrupt. */	__load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |			PSW_MASK_IO | PSW_MASK_EXT);} void cpu_idle(void){	for (;;) {		while (!need_resched())			default_idle(); 		preempt_enable_no_resched();		schedule();		preempt_disable();	}} void show_regs(struct pt_regs *regs){	struct task_struct *tsk = current;         printk("CPU:    %d    %s\n", task_thread_info(tsk)->cpu, print_tainted());        printk("Process %s (pid: %d, task: %p, ksp: %p)\n",	       current->comm, current->pid, (void *) tsk,	       (void *) tsk->thread.ksp); 	show_registers(regs);	/* Show stack backtrace if pt_regs is from kernel mode */	if (!(regs->psw.mask & PSW_MASK_PSTATE))		show_trace(NULL, (unsigned long *) regs->gprs[15]);} extern void kernel_thread_starter(void); asm(	".align 4\n"	"kernel_thread_starter:\n"	"    la    2,0(10)\n"	"    basr  14,9\n"	"    la    2,0\n"	"    br    11\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_IO | PSW_MASK_EXT;	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);} /* * Free current thread data structures etc.. */void exit_thread(void){} void flush_thread(void){	clear_used_math();	clear_tsk_thread_flag(current, TIF_USEDFPU);} void release_thread(struct task_struct *dead_task){} int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,	unsigned long unused,        struct task_struct * p, struct pt_regs * regs){        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));        p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;	/* 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);        p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;	/* Set a new TLS ?  */	if (clone_flags & CLONE_SETTLS) {		if (test_thread_flag(TIF_31BIT)) {			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_info,0,sizeof(p->thread.per_info));         return 0;} asmlinkage long sys_fork(struct pt_regs regs){	return do_fork(SIGCHLD, regs.gprs[15], &regs, 0, NULL, NULL);} asmlinkage long sys_clone(struct pt_regs regs){        unsigned long clone_flags;        unsigned long newsp;	int __user *parent_tidptr, *child_tidptr;         clone_flags = regs.gprs[3];        newsp = regs.orig_gpr2;	parent_tidptr = (int __user *) regs.gprs[4];	child_tidptr = (int __user *) regs.gprs[5];        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. */asmlinkage long sys_vfork(struct pt_regs regs){	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,		       regs.gprs[15], &regs, 0, NULL, NULL);} /* * sys_execve() executes a new program. */asmlinkage long sys_execve(struct pt_regs regs){        int error;        char * filename;         filename = getname((char __user *) regs.orig_gpr2);        error = PTR_ERR(filename);        if (IS_ERR(filename))                goto out;        error = do_execve(filename, (char __user * __user *) regs.gprs[3],			  (char __user * __user *) regs.gprs[4], &regs);	if (error == 0) {		task_lock(current);		current->ptrace &= ~PT_DTRACE;		task_unlock(current);		current->thread.fp_regs.fpc = 0;		if (MACHINE_HAS_IEEE)			asm volatile("sfpc %0,%0" : : "d" (0));	}        putname(filename);out:        return error;}  /* * 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;} 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;}