/* * OpenRISC process.c * * Linux architectural port borrowing liberally from similar works of * others.  All original copyrights apply as per the original source * declaration. * * Modifications for the OpenRISC architecture: * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> * *      This program is free software; you can redistribute it and/or *      modify it under the terms of the GNU General Public License *      as published by the Free Software Foundation; either version *      2 of the License, or (at your option) any later version. * * This file handles the architecture-dependent parts of process handling... */ #define __KERNEL_SYSCALLS__#include <stdarg.h> #include <linux/errno.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/mm.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/ptrace.h>#include <linux/slab.h>#include <linux/elfcore.h>#include <linux/interrupt.h>#include <linux/delay.h>#include <linux/init_task.h>#include <linux/mqueue.h>#include <linux/fs.h> #include <asm/uaccess.h>#include <asm/pgtable.h>#include <asm/system.h>#include <asm/io.h>#include <asm/processor.h>#include <asm/spr_defs.h> #include <linux/smp.h> /* * Pointer to Current thread info structure. * * Used at user space -> kernel transitions. */struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, }; void machine_restart(void){	printk(KERN_INFO "*** MACHINE RESTART ***\n");	__asm__("l.nop 1");} /* * Similar to machine_power_off, but don't shut off power.  Add code * here to freeze the system for e.g. post-mortem debug purpose when * possible.  This halt has nothing to do with the idle halt. */void machine_halt(void){	printk(KERN_INFO "*** MACHINE HALT ***\n");	__asm__("l.nop 1");} /* If or when software power-off is implemented, add code here.  */void machine_power_off(void){	printk(KERN_INFO "*** MACHINE POWER OFF ***\n");	__asm__("l.nop 1");} void (*pm_power_off) (void) = machine_power_off; /* * When a process does an "exec", machine state like FPU and debug * registers need to be reset.  This is a hook function for that. * Currently we don't have any such state to reset, so this is empty. */void flush_thread(void){} void show_regs(struct pt_regs *regs){	extern void show_registers(struct pt_regs *regs); 	/* __PHX__ cleanup this mess */	show_registers(regs);} unsigned long thread_saved_pc(struct task_struct *t){	return (unsigned long)user_regs(t->stack)->pc;} void release_thread(struct task_struct *dead_task){} /* * Copy the thread-specific (arch specific) info from the current * process to the new one p */extern asmlinkage void ret_from_fork(void); intcopy_thread(unsigned long clone_flags, unsigned long usp,	    unsigned long unused, struct task_struct *p, struct pt_regs *regs){	struct pt_regs *childregs;	struct pt_regs *kregs;	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;	struct thread_info *ti;	unsigned long top_of_kernel_stack; 	top_of_kernel_stack = sp; 	p->set_child_tid = p->clear_child_tid = NULL; 	/* Copy registers */	/* redzone */	sp -= STACK_FRAME_OVERHEAD;	sp -= sizeof(struct pt_regs);	childregs = (struct pt_regs *)sp; 	/* Copy parent registers */	*childregs = *regs; 	if ((childregs->sr & SPR_SR_SM) == 1) {		/* for kernel thread, set `current_thread_info'		 * and stackptr in new task		 */		childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;		childregs->gpr[10] = (unsigned long)task_thread_info(p);	} else {		childregs->sp = usp;	} 	childregs->gpr[11] = 0;	/* Result from fork() */ 	/*	 * The way this works is that at some point in the future	 * some task will call _switch to switch to the new task.	 * That will pop off the stack frame created below and start	 * the new task running at ret_from_fork.  The new task will	 * do some house keeping and then return from the fork or clone	 * system call, using the stack frame created above.	 */	/* redzone */	sp -= STACK_FRAME_OVERHEAD;	sp -= sizeof(struct pt_regs);	kregs = (struct pt_regs *)sp; 	ti = task_thread_info(p);	ti->ksp = sp; 	/* kregs->sp must store the location of the 'pre-switch' kernel stack	 * pointer... for a newly forked process, this is simply the top of	 * the kernel stack.	 */	kregs->sp = top_of_kernel_stack;	kregs->gpr[3] = (unsigned long)current;	/* arg to schedule_tail */	kregs->gpr[10] = (unsigned long)task_thread_info(p);	kregs->gpr[9] = (unsigned long)ret_from_fork; 	return 0;} /* * Set up a thread for executing a new program */void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp){	unsigned long sr = regs->sr & ~SPR_SR_SM; 	set_fs(USER_DS);	memset(regs->gpr, 0, sizeof(regs->gpr)); 	regs->pc = pc;	regs->sr = sr;	regs->sp = sp; /*	printk("start thread, ksp = %lx\n", current_thread_info()->ksp);*/} /* Fill in the fpu structure for a core dump.  */int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu){	/* TODO */	return 0;} extern struct thread_info *_switch(struct thread_info *old_ti,				   struct thread_info *new_ti); struct task_struct *__switch_to(struct task_struct *old,				struct task_struct *new){	struct task_struct *last;	struct thread_info *new_ti, *old_ti;	unsigned long flags; 	local_irq_save(flags); 	/* current_set is an array of saved current pointers	 * (one for each cpu). we need them at user->kernel transition,	 * while we save them at kernel->user transition	 */	new_ti = new->stack;	old_ti = old->stack; 	current_thread_info_set[smp_processor_id()] = new_ti;	last = (_switch(old_ti, new_ti))->task; 	local_irq_restore(flags); 	return last;} /* * Write out registers in core dump format, as defined by the * struct user_regs_struct */void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs){	dest[0] = 0; /* r0 */	memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));	dest[32] = regs->pc;	dest[33] = regs->sr;	dest[34] = 0;	dest[35] = 0;} extern void _kernel_thread_helper(void); void __noreturn kernel_thread_helper(int (*fn) (void *), void *arg){	do_exit(fn(arg));} /* * Create a kernel thread. */int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags){	struct pt_regs regs; 	memset(&regs, 0, sizeof(regs)); 	regs.gpr[20] = (unsigned long)fn;	regs.gpr[22] = (unsigned long)arg;	regs.sr = mfspr(SPR_SR);	regs.pc = (unsigned long)_kernel_thread_helper; 	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,		       0, &regs, 0, NULL, NULL);} /* * sys_execve() executes a new program. */asmlinkage long _sys_execve(const char __user *name,			    const char __user * const __user *argv,			    const char __user * const __user *envp,			    struct pt_regs *regs){	int error;	char *filename; 	filename = getname(name);	error = PTR_ERR(filename); 	if (IS_ERR(filename))		goto out; 	error = do_execve(filename, argv, envp, regs);	putname(filename); out:	return error;} unsigned long get_wchan(struct task_struct *p){	/* TODO */ 	return 0;} int kernel_execve(const char *filename, char *const argv[], char *const envp[]){	register long __res asm("r11") = __NR_execve;	register long __a asm("r3") = (long)(filename);	register long __b asm("r4") = (long)(argv);	register long __c asm("r5") = (long)(envp);	__asm__ volatile ("l.sys 1"			  : "=r" (__res), "=r"(__a), "=r"(__b), "=r"(__c)			  : "0"(__res), "1"(__a), "2"(__b), "3"(__c)			  : "r6", "r7", "r8", "r12", "r13", "r15",			    "r17", "r19", "r21", "r23", "r25", "r27",			    "r29", "r31");	__asm__ volatile ("l.nop");	return __res;}