// SPDX-License-Identifier: GPL-2.0/*  linux/arch/sparc/kernel/process.c * *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net) *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be) */ /* * This file handles the architecture-dependent parts of process handling.. */#include <linux/elfcore.h>#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/stddef.h>#include <linux/ptrace.h>#include <linux/user.h>#include <linux/smp.h>#include <linux/reboot.h>#include <linux/delay.h>#include <linux/pm.h>#include <linux/slab.h>#include <linux/cpu.h> #include <asm/auxio.h>#include <asm/oplib.h>#include <linux/uaccess.h>#include <asm/page.h>#include <asm/delay.h>#include <asm/processor.h>#include <asm/psr.h>#include <asm/elf.h>#include <asm/prom.h>#include <asm/unistd.h>#include <asm/setup.h> #include "kernel.h" /*  * Power management idle function  * Set in pm platform drivers (apc.c and pmc.c) */void (*sparc_idle)(void); /*  * Power-off handler instantiation for pm.h compliance * This is done via auxio, but could be used as a fallback * handler when auxio is not present-- unused for now... */void (*pm_power_off)(void) = machine_power_off;EXPORT_SYMBOL(pm_power_off); /* * sysctl - toggle power-off restriction for serial console  * systems in machine_power_off() */int scons_pwroff = 1; extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *); struct task_struct *last_task_used_math = NULL;struct thread_info *current_set[NR_CPUS]; /* Idle loop support. */void arch_cpu_idle(void){	if (sparc_idle)		(*sparc_idle)();} /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */void machine_halt(void){	local_irq_enable();	mdelay(8);	local_irq_disable();	prom_halt();	panic("Halt failed!");} void machine_restart(char * cmd){	char *p;		local_irq_enable();	mdelay(8);	local_irq_disable(); 	p = strchr (reboot_command, '\n');	if (p) *p = 0;	if (cmd)		prom_reboot(cmd);	if (*reboot_command)		prom_reboot(reboot_command);	prom_feval ("reset");	panic("Reboot failed!");} void machine_power_off(void){	if (auxio_power_register &&	    (!of_node_is_type(of_console_device, "serial") || scons_pwroff)) {		u8 power_register = sbus_readb(auxio_power_register);		power_register |= AUXIO_POWER_OFF;		sbus_writeb(power_register, auxio_power_register);	} 	machine_halt();} void show_regs(struct pt_regs *r){	struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14]; 	show_regs_print_info(KERN_DEFAULT);         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",	       r->psr, r->pc, r->npc, r->y, print_tainted());	printk("PC: <%pS>\n", (void *) r->pc);	printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",	       r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],	       r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);	printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",	       r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],	       r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);	printk("RPC: <%pS>\n", (void *) r->u_regs[15]); 	printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",	       rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],	       rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);	printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",	       rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],	       rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);} /* * The show_stack() is external API which we do not use ourselves. * The oops is printed in die_if_kernel. */void show_stack(struct task_struct *tsk, unsigned long *_ksp, const char *loglvl){	unsigned long pc, fp;	unsigned long task_base;	struct reg_window32 *rw;	int count = 0; 	if (!tsk)		tsk = current; 	if (tsk == current && !_ksp)		__asm__ __volatile__("mov	%%fp, %0" : "=r" (_ksp)); 	task_base = (unsigned long) task_stack_page(tsk);	fp = (unsigned long) _ksp;	do {		/* Bogus frame pointer? */		if (fp < (task_base + sizeof(struct thread_info)) ||		    fp >= (task_base + (PAGE_SIZE << 1)))			break;		rw = (struct reg_window32 *) fp;		pc = rw->ins[7];		printk("%s[%08lx : ", loglvl, pc);		printk("%s%pS ] ", loglvl, (void *) pc);		fp = rw->ins[6];	} while (++count < 16);	printk("%s\n", loglvl);} /* * Free current thread data structures etc.. */void exit_thread(struct task_struct *tsk){#ifndef CONFIG_SMP	if (last_task_used_math == tsk) {#else	if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {#endif		/* Keep process from leaving FPU in a bogon state. */		put_psr(get_psr() | PSR_EF);		fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,		       &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);#ifndef CONFIG_SMP		last_task_used_math = NULL;#else		clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);#endif	}} void flush_thread(void){	current_thread_info()->w_saved = 0; #ifndef CONFIG_SMP	if(last_task_used_math == current) {#else	if (test_thread_flag(TIF_USEDFPU)) {#endif		/* Clean the fpu. */		put_psr(get_psr() | PSR_EF);		fpsave(&current->thread.float_regs[0], &current->thread.fsr,		       &current->thread.fpqueue[0], &current->thread.fpqdepth);#ifndef CONFIG_SMP		last_task_used_math = NULL;#else		clear_thread_flag(TIF_USEDFPU);#endif	}} static inline struct sparc_stackf __user *clone_stackframe(struct sparc_stackf __user *dst,		 struct sparc_stackf __user *src){	unsigned long size, fp;	struct sparc_stackf *tmp;	struct sparc_stackf __user *sp; 	if (get_user(tmp, &src->fp))		return NULL; 	fp = (unsigned long) tmp;	size = (fp - ((unsigned long) src));	fp = (unsigned long) dst;	sp = (struct sparc_stackf __user *)(fp - size);  	/* do_fork() grabs the parent semaphore, we must release it	 * temporarily so we can build the child clone stack frame	 * without deadlocking.	 */	if (__copy_user(sp, src, size))		sp = NULL;	else if (put_user(fp, &sp->fp))		sp = NULL; 	return sp;} /* Copy a Sparc thread.  The fork() return value conventions * under SunOS are nothing short of bletcherous: * Parent -->  %o0 == childs  pid, %o1 == 0 * Child  -->  %o0 == parents pid, %o1 == 1 * * clone3() - Uses regular kernel return value conventions * * NOTE: We have a separate fork kpsr/kwim because *       the parent could change these values between *       sys_fork invocation and when we reach here *       if the parent should sleep while trying to *       allocate the task_struct and kernel stack in *       do_fork(). * XXX See comment above sys_vfork in sparc64. todo. */extern void ret_from_fork(void);extern void ret_from_kernel_thread(void); int copy_thread(struct task_struct *p, const struct kernel_clone_args *args){	u64 clone_flags = args->flags;	unsigned long tls = args->tls;	struct thread_info *ti = task_thread_info(p);	struct pt_regs *childregs, *regs = current_pt_regs();	char *new_stack;	unsigned long sp = args->stack ? args->stack : regs->u_regs[UREG_FP]; #ifndef CONFIG_SMP	if(last_task_used_math == current) {#else	if (test_thread_flag(TIF_USEDFPU)) {#endif		put_psr(get_psr() | PSR_EF);		fpsave(&p->thread.float_regs[0], &p->thread.fsr,		       &p->thread.fpqueue[0], &p->thread.fpqdepth);	} 	/*	 *  p->thread_info         new_stack   childregs stack bottom	 *  !                      !           !             !	 *  V                      V (stk.fr.) V  (pt_regs)  V	 *  +----- - - - - - ------+===========+=============+	 */	new_stack = task_stack_page(p) + THREAD_SIZE;	new_stack -= STACKFRAME_SZ + TRACEREG_SZ;	childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ); 	/*	 * A new process must start with interrupts disabled, see schedule_tail()	 * and finish_task_switch(). (If we do not do it and if a timer interrupt	 * hits before we unlock and attempts to take the rq->lock, we deadlock.)	 *	 * Thus, kpsr |= PSR_PIL.	 */	ti->ksp = (unsigned long) new_stack;	p->thread.kregs = childregs; 	if (unlikely(args->fn)) {		extern int nwindows;		unsigned long psr;		memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);		ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);		childregs->u_regs[UREG_G1] = (unsigned long) args->fn;		childregs->u_regs[UREG_G2] = (unsigned long) args->fn_arg;		psr = childregs->psr = get_psr();		ti->kpsr = psr | PSR_PIL;		ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);		return 0;	}	memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);	childregs->u_regs[UREG_FP] = sp;	ti->kpc = (((unsigned long) ret_from_fork) - 0x8);	ti->kpsr = current->thread.fork_kpsr | PSR_PIL;	ti->kwim = current->thread.fork_kwim; 	if (sp != regs->u_regs[UREG_FP]) {		struct sparc_stackf __user *childstack;		struct sparc_stackf __user *parentstack; 		/*		 * This is a clone() call with supplied user stack.		 * Set some valid stack frames to give to the child.		 */		childstack = (struct sparc_stackf __user *)			(sp & ~0xfUL);		parentstack = (struct sparc_stackf __user *)			regs->u_regs[UREG_FP]; #if 0		printk("clone: parent stack:\n");		show_stackframe(parentstack);#endif 		childstack = clone_stackframe(childstack, parentstack);		if (!childstack)			return -EFAULT; #if 0		printk("clone: child stack:\n");		show_stackframe(childstack);#endif 		childregs->u_regs[UREG_FP] = (unsigned long)childstack;	} #ifdef CONFIG_SMP	/* FPU must be disabled on SMP. */	childregs->psr &= ~PSR_EF;	clear_tsk_thread_flag(p, TIF_USEDFPU);#endif	/* Handle return value conventions */	if (regs->u_regs[UREG_G1] == __NR_clone3) {		/* clone3() - use regular kernel return value convention */ 		/* Set the return value for the child. */		childregs->u_regs[UREG_I0] = 0;	} else {		/* clone()/fork() - use SunOS return value convention */ 		/* Set the return value for the child. */		childregs->u_regs[UREG_I0] = current->pid;		childregs->u_regs[UREG_I1] = 1; 		/* Set the return value for the parent. */		regs->u_regs[UREG_I1] = 0;	} 	if (clone_flags & CLONE_SETTLS)		childregs->u_regs[UREG_G7] = tls; 	return 0;} unsigned long __get_wchan(struct task_struct *task){	unsigned long pc, fp, bias = 0;	unsigned long task_base = (unsigned long) task;        unsigned long ret = 0;	struct reg_window32 *rw;	int count = 0; 	fp = task_thread_info(task)->ksp + bias;	do {		/* Bogus frame pointer? */		if (fp < (task_base + sizeof(struct thread_info)) ||		    fp >= (task_base + (2 * PAGE_SIZE)))			break;		rw = (struct reg_window32 *) fp;		pc = rw->ins[7];		if (!in_sched_functions(pc)) {			ret = pc;			goto out;		}		fp = rw->ins[6] + bias;	} while (++count < 16); out:	return ret;}