// SPDX-License-Identifier: GPL-2.0-or-later #include <linux/capability.h>#include <linux/cpu.h>#include <linux/init.h>#include <linux/prctl.h>#include <linux/sched.h> #include <asm/cpu_has_feature.h>#include <asm/cputable.h>#include <asm/processor.h>#include <asm/reg.h> static int __init init_task_dexcr(void){	if (!early_cpu_has_feature(CPU_FTR_ARCH_31))		return 0; 	current->thread.dexcr_onexec = mfspr(SPRN_DEXCR); 	return 0;}early_initcall(init_task_dexcr) /* Allow thread local configuration of these by default */#define DEXCR_PRCTL_EDITABLE ( \	DEXCR_PR_IBRTPD | \	DEXCR_PR_SRAPD | \	DEXCR_PR_NPHIE) static int prctl_to_aspect(unsigned long which, unsigned int *aspect){	switch (which) {	case PR_PPC_DEXCR_SBHE:		*aspect = DEXCR_PR_SBHE;		break;	case PR_PPC_DEXCR_IBRTPD:		*aspect = DEXCR_PR_IBRTPD;		break;	case PR_PPC_DEXCR_SRAPD:		*aspect = DEXCR_PR_SRAPD;		break;	case PR_PPC_DEXCR_NPHIE:		*aspect = DEXCR_PR_NPHIE;		break;	default:		return -ENODEV;	} 	return 0;} int get_dexcr_prctl(struct task_struct *task, unsigned long which){	unsigned int aspect;	int ret; 	ret = prctl_to_aspect(which, &aspect);	if (ret)		return ret; 	if (aspect & DEXCR_PRCTL_EDITABLE)		ret |= PR_PPC_DEXCR_CTRL_EDITABLE; 	if (aspect & mfspr(SPRN_DEXCR))		ret |= PR_PPC_DEXCR_CTRL_SET;	else		ret |= PR_PPC_DEXCR_CTRL_CLEAR; 	if (aspect & task->thread.dexcr_onexec)		ret |= PR_PPC_DEXCR_CTRL_SET_ONEXEC;	else		ret |= PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC; 	return ret;} int set_dexcr_prctl(struct task_struct *task, unsigned long which, unsigned long ctrl){	unsigned long dexcr;	unsigned int aspect;	int err = 0; 	err = prctl_to_aspect(which, &aspect);	if (err)		return err; 	if (!(aspect & DEXCR_PRCTL_EDITABLE))		return -EPERM; 	if (ctrl & ~PR_PPC_DEXCR_CTRL_MASK)		return -EINVAL; 	if (ctrl & PR_PPC_DEXCR_CTRL_SET && ctrl & PR_PPC_DEXCR_CTRL_CLEAR)		return -EINVAL; 	if (ctrl & PR_PPC_DEXCR_CTRL_SET_ONEXEC && ctrl & PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC)		return -EINVAL; 	/*	 * We do not want an unprivileged process being able to disable	 * a setuid process's hash check instructions	 */	if (aspect == DEXCR_PR_NPHIE &&	    ctrl & PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC &&	    !capable(CAP_SYS_ADMIN))		return -EPERM; 	dexcr = mfspr(SPRN_DEXCR); 	if (ctrl & PR_PPC_DEXCR_CTRL_SET)		dexcr |= aspect;	else if (ctrl & PR_PPC_DEXCR_CTRL_CLEAR)		dexcr &= ~aspect; 	if (ctrl & PR_PPC_DEXCR_CTRL_SET_ONEXEC)		task->thread.dexcr_onexec |= aspect;	else if (ctrl & PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC)		task->thread.dexcr_onexec &= ~aspect; 	mtspr(SPRN_DEXCR, dexcr); 	return 0;}