// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2024 Rivos Inc. */ #include <linux/cpu.h>#include <linux/device.h>#include <linux/sysfs.h> #include <asm/bugs.h>#include <asm/vendor_extensions/thead.h> static enum mitigation_state ghostwrite_state; void ghostwrite_set_vulnerable(void){	ghostwrite_state = VULNERABLE;} /* * Vendor extension alternatives will use the value set at the time of boot * alternative patching, thus this must be called before boot alternatives are * patched (and after extension probing) to be effective. * * Returns true if mitgated, false otherwise. */bool ghostwrite_enable_mitigation(void){	if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR) &&	    ghostwrite_state == VULNERABLE && !cpu_mitigations_off()) {		disable_xtheadvector();		ghostwrite_state = MITIGATED;		return true;	} 	return false;} enum mitigation_state ghostwrite_get_state(void){	return ghostwrite_state;} ssize_t cpu_show_ghostwrite(struct device *dev, struct device_attribute *attr, char *buf){	if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR)) {		switch (ghostwrite_state) {		case UNAFFECTED:			return sysfs_emit(buf, "Not affected\n");		case MITIGATED:			return sysfs_emit(buf, "Mitigation: xtheadvector disabled\n");		case VULNERABLE:			fallthrough;		default:			return sysfs_emit(buf, "Vulnerable\n");		}	} 	return sysfs_emit(buf, "Not affected\n");}