// SPDX-License-Identifier: GPL-2.0-or-later/* * 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 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/sched/debug.h>#include <linux/sched/task.h>#include <linux/sched/task_stack.h>#include <linux/kernel.h>#include <linux/export.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 <linux/reboot.h> #include <linux/uaccess.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(char *cmd){	do_kernel_restart(cmd); 	/* Give a grace period for failure to restart of 1s */	mdelay(1000); 	/* Whoops - the platform was unable to reboot. Tell the user! */	pr_emerg("Reboot failed -- System halted\n");	while (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");} /* * Send the doze signal to the cpu if available. * Make sure, that all interrupts are enabled */void arch_cpu_idle(void){	raw_local_irq_enable();	if (mfspr(SPR_UPR) & SPR_UPR_PMP)		mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);} void (*pm_power_off) (void) = machine_power_off;EXPORT_SYMBOL(pm_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); 	show_regs_print_info(KERN_DEFAULT);	/* __PHX__ cleanup this mess */	show_registers(regs);} 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); /* * copy_thread * @clone_flags: flags * @usp: user stack pointer or fn for kernel thread * @arg: arg to fn for kernel thread; always NULL for userspace thread * @p: the newly created task * @tls: the Thread Local Storage pointer for the new process * * At the top of a newly initialized kernel stack are two stacked pt_reg * structures.  The first (topmost) is the userspace context of the thread. * The second is the kernelspace context of the thread. * * A kernel thread will not be returning to userspace, so the topmost pt_regs * struct can be uninitialized; it _does_ need to exist, though, because * a kernel thread can become a userspace thread by doing a kernel_execve, in * which case the topmost context will be initialized and used for 'returning' * to userspace. * * The second pt_reg struct needs to be initialized to 'return' to * ret_from_fork.  A kernel thread will need to set r20 to the address of * a function to call into (with arg in r22); userspace threads need to set * r20 to NULL in which case ret_from_fork will just continue a return to * userspace. * * A kernel thread 'fn' may return; this is effectively what happens when * kernel_execve is called.  In that case, the userspace pt_regs must have * been initialized (which kernel_execve takes care of, see start_thread * below); ret_from_fork will then continue its execution causing the * 'kernel thread' to return to userspace as a userspace thread. */ intcopy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,	    struct task_struct *p, unsigned long tls){	struct pt_regs *userregs;	struct pt_regs *kregs;	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;	unsigned long top_of_kernel_stack; 	top_of_kernel_stack = sp; 	/* Locate userspace context on stack... */	sp -= STACK_FRAME_OVERHEAD;	/* redzone */	sp -= sizeof(struct pt_regs);	userregs = (struct pt_regs *) sp; 	/* ...and kernel context */	sp -= STACK_FRAME_OVERHEAD;	/* redzone */	sp -= sizeof(struct pt_regs);	kregs = (struct pt_regs *)sp; 	if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {		memset(kregs, 0, sizeof(struct pt_regs));		kregs->gpr[20] = usp; /* fn, kernel thread */		kregs->gpr[22] = arg;	} else {		*userregs = *current_pt_regs(); 		if (usp)			userregs->sp = usp; 		/*		 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer.		 */		if (clone_flags & CLONE_SETTLS)			userregs->gpr[10] = tls; 		userregs->gpr[11] = 0;	/* Result from fork() */ 		kregs->gpr[20] = 0;	/* Userspace thread */	} 	/*	 * _switch wants the kernel stack page in pt_regs->sp so that it	 * can restore it to thread_info->ksp... see _switch for details.	 */	kregs->sp = top_of_kernel_stack;	kregs->gpr[9] = (unsigned long)ret_from_fork; 	task_thread_info(p)->ksp = (unsigned long)kregs; 	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 = mfspr(SPR_SR) & ~SPR_SR_SM; 	memset(regs, 0, sizeof(struct pt_regs)); 	regs->pc = pc;	regs->sr = sr;	regs->sp = sp;} extern struct thread_info *_switch(struct thread_info *old_ti,				   struct thread_info *new_ti);extern int lwa_flag; 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; 	lwa_flag = 0; 	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;} unsigned long get_wchan(struct task_struct *p){	/* TODO */ 	return 0;}