// SPDX-License-Identifier: GPL-2.0/* *  linux/arch/m68k/kernel/process.c * *  Copyright (C) 1995  Hamish Macdonald * *  68060 fixes by Jesper Skov */ /* * This file handles the architecture-dependent parts of process handling.. */ #include <linux/errno.h>#include <linux/module.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/slab.h>#include <linux/fs.h>#include <linux/smp.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/ptrace.h>#include <linux/user.h>#include <linux/reboot.h>#include <linux/init_task.h>#include <linux/mqueue.h>#include <linux/rcupdate.h>#include <linux/syscalls.h>#include <linux/uaccess.h>#include <linux/elfcore.h> #include <asm/traps.h>#include <asm/machdep.h>#include <asm/setup.h> #include "process.h" asmlinkage void ret_from_fork(void);asmlinkage void ret_from_kernel_thread(void); void arch_cpu_idle(void){#if defined(MACH_ATARI_ONLY)	/* block out HSYNC on the atari (falcon) */	__asm__("stop #0x2200" : : : "cc");#else	__asm__("stop #0x2000" : : : "cc");#endif} void machine_restart(char * __unused){	if (mach_reset)		mach_reset();	for (;;);} void machine_halt(void){	if (mach_halt)		mach_halt();	for (;;);} void machine_power_off(void){	do_kernel_power_off();	for (;;);} void (*pm_power_off)(void);EXPORT_SYMBOL(pm_power_off); void show_regs(struct pt_regs * regs){	pr_info("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",		regs->format, regs->vector, regs->pc, regs->sr,		print_tainted());	pr_info("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",		regs->orig_d0, regs->d0, regs->a2, regs->a1);	pr_info("A0: %08lx  D5: %08lx  D4: %08lx\n", regs->a0, regs->d5,		regs->d4);	pr_info("D3: %08lx  D2: %08lx  D1: %08lx\n", regs->d3, regs->d2,		regs->d1);	if (!(regs->sr & PS_S))		pr_info("USP: %08lx\n", rdusp());} void flush_thread(void){	current->thread.fc = USER_DATA;#ifdef CONFIG_FPU	if (!FPU_IS_EMU) {		unsigned long zero = 0;		asm volatile("frestore %0": :"m" (zero));	}#endif} /* * Why not generic sys_clone, you ask?  m68k passes all arguments on stack. * And we need all registers saved, which means a bunch of stuff pushed * on top of pt_regs, which means that sys_clone() arguments would be * buried.  We could, of course, copy them, but it's too costly for no * good reason - generic clone() would have to copy them *again* for * kernel_clone() anyway.  So in this case it's actually better to pass pt_regs * * and extract arguments for kernel_clone() from there.  Eventually we might * go for calling kernel_clone() directly from the wrapper, but only after we * are finished with kernel_clone() prototype conversion. */asmlinkage int m68k_clone(struct pt_regs *regs){	/* regs will be equal to current_pt_regs() */	struct kernel_clone_args args = {		.flags		= (u32)(regs->d1) & ~CSIGNAL,		.pidfd		= (int __user *)regs->d3,		.child_tid	= (int __user *)regs->d4,		.parent_tid	= (int __user *)regs->d3,		.exit_signal	= regs->d1 & CSIGNAL,		.stack		= regs->d2,		.tls		= regs->d5,	}; 	return kernel_clone(&args);} /* * Because extra registers are saved on the stack after the sys_clone3() * arguments, this C wrapper extracts them from pt_regs * and then calls the * generic sys_clone3() implementation. */asmlinkage int m68k_clone3(struct pt_regs *regs){	return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);} int copy_thread(struct task_struct *p, const struct kernel_clone_args *args){	u64 clone_flags = args->flags;	unsigned long usp = args->stack;	unsigned long tls = args->tls;	struct fork_frame {		struct switch_stack sw;		struct pt_regs regs;	} *frame; 	frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1; 	p->thread.ksp = (unsigned long)frame;	p->thread.esp0 = (unsigned long)&frame->regs; 	/*	 * Must save the current SFC/DFC value, NOT the value when	 * the parent was last descheduled - RGH  10-08-96	 */	p->thread.fc = USER_DATA; 	if (unlikely(args->fn)) {		/* kernel thread */		memset(frame, 0, sizeof(struct fork_frame));		frame->regs.sr = PS_S;		frame->sw.a3 = (unsigned long)args->fn;		frame->sw.d7 = (unsigned long)args->fn_arg;		frame->sw.retpc = (unsigned long)ret_from_kernel_thread;		p->thread.usp = 0;		return 0;	}	memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),		sizeof(struct fork_frame));	frame->regs.d0 = 0;	frame->sw.retpc = (unsigned long)ret_from_fork;	p->thread.usp = usp ?: rdusp(); 	if (clone_flags & CLONE_SETTLS)		task_thread_info(p)->tp_value = tls; #ifdef CONFIG_FPU	if (!FPU_IS_EMU) {		/* Copy the current fpu state */		asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory"); 		if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {			if (CPU_IS_COLDFIRE) {				asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"					      "fmovel %/fpiar,%1\n\t"					      "fmovel %/fpcr,%2\n\t"					      "fmovel %/fpsr,%3"					      :					      : "m" (p->thread.fp[0]),						"m" (p->thread.fpcntl[0]),						"m" (p->thread.fpcntl[1]),						"m" (p->thread.fpcntl[2])					      : "memory");			} else {				asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"					      "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"					      :					      : "m" (p->thread.fp[0]),						"m" (p->thread.fpcntl[0])					      : "memory");			}		} 		/* Restore the state in case the fpu was busy */		asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));	}#endif /* CONFIG_FPU */ 	return 0;} /* Fill in the fpu structure for a core dump.  */int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu){	if (FPU_IS_EMU) {		int i; 		memcpy(fpu->fpcntl, current->thread.fpcntl, 12);		memcpy(fpu->fpregs, current->thread.fp, 96);		/* Convert internal fpu reg representation		 * into long double format		 */		for (i = 0; i < 24; i += 3)			fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |			                 ((fpu->fpregs[i] & 0x0000ffff) << 16);		return 1;	} 	if (IS_ENABLED(CONFIG_FPU)) {		char fpustate[216]; 		/* First dump the fpu context to avoid protocol violation.  */		asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");		if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])			return 0; 		if (CPU_IS_COLDFIRE) {			asm volatile ("fmovel %/fpiar,%0\n\t"				      "fmovel %/fpcr,%1\n\t"				      "fmovel %/fpsr,%2\n\t"				      "fmovemd %/fp0-%/fp7,%3"				      :				      : "m" (fpu->fpcntl[0]),					"m" (fpu->fpcntl[1]),					"m" (fpu->fpcntl[2]),					"m" (fpu->fpregs[0])				      : "memory");		} else {			asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"				      :				      : "m" (fpu->fpcntl[0])				      : "memory");			asm volatile ("fmovemx %/fp0-%/fp7,%0"				      :				      : "m" (fpu->fpregs[0])				      : "memory");		}	} 	return 1;} unsigned long __get_wchan(struct task_struct *p){	unsigned long fp, pc;	unsigned long stack_page;	int count = 0; 	stack_page = (unsigned long)task_stack_page(p);	fp = ((struct switch_stack *)p->thread.ksp)->a6;	do {		if (fp < stack_page+sizeof(struct thread_info) ||		    fp >= 8184+stack_page)			return 0;		pc = ((unsigned long *)fp)[1];		if (!in_sched_functions(pc))			return pc;		fp = *(unsigned long *) fp;	} while (count++ < 16);	return 0;}