linux-stable/arch/s390/kernel/nospec-sysfs.c
Martin Schwidefsky 4253b0e062 s390: move spectre sysfs attribute code
The nospec-branch.c file is compiled without the gcc options to
generate expoline thunks. The return branch of the sysfs show
functions cpu_show_spectre_v1 and cpu_show_spectre_v2 is an indirect
branch as well. These need to be compiled with expolines.

Move the sysfs functions for spectre reporting to a separate file
and loose an '.' for one of the messages.

Cc: stable@vger.kernel.org # 4.16
Fixes: d424986f1d ("s390: add sysfs attributes for spectre")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-05-07 21:12:41 +02:00

21 lines
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C

// SPDX-License-Identifier: GPL-2.0
#include <linux/device.h>
#include <linux/cpu.h>
#include <asm/facility.h>
#include <asm/nospec-branch.h>
ssize_t cpu_show_spectre_v1(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "Mitigation: __user pointer sanitization\n");
}
ssize_t cpu_show_spectre_v2(struct device *dev,
struct device_attribute *attr, char *buf)
{
if (IS_ENABLED(CC_USING_EXPOLINE) && !nospec_disable)
return sprintf(buf, "Mitigation: execute trampolines\n");
if (__test_facility(82, S390_lowcore.alt_stfle_fac_list))
return sprintf(buf, "Mitigation: limited branch prediction\n");
return sprintf(buf, "Vulnerable\n");
}