// SPDX-License-Identifier: GPL-2.0-only/* *  Port on Texas Instruments TMS320C6x architecture * *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com) */#include <linux/module.h>#include <linux/unistd.h>#include <linux/ptrace.h>#include <linux/init_task.h>#include <linux/tick.h>#include <linux/mqueue.h>#include <linux/syscalls.h>#include <linux/reboot.h>#include <linux/sched/task.h>#include <linux/sched/task_stack.h> #include <asm/syscalls.h> /* hooks for board specific support */void	(*c6x_restart)(void);void	(*c6x_halt)(void); extern asmlinkage void ret_from_fork(void);extern asmlinkage void ret_from_kernel_thread(void); /* * power off function, if any */void (*pm_power_off)(void);EXPORT_SYMBOL(pm_power_off); void arch_cpu_idle(void){	unsigned long tmp; 	/*	 * Put local_irq_enable and idle in same execute packet	 * to make them atomic and avoid race to idle with	 * interrupts enabled.	 */	asm volatile ("   mvc .s2 CSR,%0\n"		      "   or  .d2 1,%0,%0\n"		      "   mvc .s2 %0,CSR\n"		      "|| idle\n"		      : "=b"(tmp));} static void halt_loop(void){	printk(KERN_EMERG "System Halted, OK to turn off power\n");	local_irq_disable();	while (1)		asm volatile("idle\n");} void machine_restart(char *__unused){	if (c6x_restart)		c6x_restart();	halt_loop();} void machine_halt(void){	if (c6x_halt)		c6x_halt();	halt_loop();} void machine_power_off(void){	if (pm_power_off)		pm_power_off();	halt_loop();} void flush_thread(void){} /* * Do necessary setup to start up a newly executed thread. */void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp){	/*	 * The binfmt loader will setup a "full" stack, but the C6X	 * operates an "empty" stack. So we adjust the usp so that	 * argc doesn't get destroyed if an interrupt is taken before	 * it is read from the stack.	 *	 * NB: Library startup code needs to match this.	 */	usp -= 8; 	regs->pc  = pc;	regs->sp  = usp;	regs->tsr |= 0x40; /* set user mode */	current->thread.usp = usp;} /* * Copy a new thread context in its stack. */int copy_thread(unsigned long clone_flags, unsigned long usp,		unsigned long ustk_size, struct task_struct *p,		unsigned long tls){	struct pt_regs *childregs; 	childregs = task_pt_regs(p); 	if (unlikely(p->flags & PF_KTHREAD)) {		/* case of  __kernel_thread: we return to supervisor space */		memset(childregs, 0, sizeof(struct pt_regs));		childregs->sp = (unsigned long)(childregs + 1);		p->thread.pc = (unsigned long) ret_from_kernel_thread;		childregs->a0 = usp;		/* function */		childregs->a1 = ustk_size;	/* argument */	} else {		/* Otherwise use the given stack */		*childregs = *current_pt_regs();		if (usp)			childregs->sp = usp;		p->thread.pc = (unsigned long) ret_from_fork;	} 	/* Set usp/ksp */	p->thread.usp = childregs->sp;	thread_saved_ksp(p) = (unsigned long)childregs - 8;	p->thread.wchan	= p->thread.pc;#ifdef __DSBT__	{		unsigned long dp; 		asm volatile ("mv .S2 b14,%0\n" : "=b"(dp)); 		thread_saved_dp(p) = dp;		if (usp == -1)			childregs->dp = dp;	}#endif	return 0;} unsigned long get_wchan(struct task_struct *p){	return p->thread.wchan;}