61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright (C) 2024 Rivos Inc.
|
|
*/
|
|
|
|
#include <linux/cpu.h>
|
|
#include <linux/device.h>
|
|
#include <linux/sprintf.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 sprintf(buf, "Not affected\n");
|
|
case MITIGATED:
|
|
return sprintf(buf, "Mitigation: xtheadvector disabled\n");
|
|
case VULNERABLE:
|
|
fallthrough;
|
|
default:
|
|
return sprintf(buf, "Vulnerable\n");
|
|
}
|
|
} else {
|
|
return sprintf(buf, "Not affected\n");
|
|
}
|
|
}
|