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| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2024-03-11 22:29:43 +0300 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2024-03-15 17:48:22 +0300 |
| commit | 77018fb9efe50cf24e61275ee09253cf1fbb6854 (patch) | |
| tree | 215f6218366f411d29b09c665f3303eb92837889 /include/linux/cpu.h | |
| parent | ddfd38558acc5b3891fd197372fedb76372da740 (diff) | |
| download | linux-77018fb9efe50cf24e61275ee09253cf1fbb6854.tar.xz | |
x86/rfds: Mitigate Register File Data Sampling (RFDS)
commit 8076fcde016c9c0e0660543e67bff86cb48a7c9c upstream.
RFDS is a CPU vulnerability that may allow userspace to infer kernel
stale data previously used in floating point registers, vector registers
and integer registers. RFDS only affects certain Intel Atom processors.
Intel released a microcode update that uses VERW instruction to clear
the affected CPU buffers. Unlike MDS, none of the affected cores support
SMT.
Add RFDS bug infrastructure and enable the VERW based mitigation by
default, that clears the affected buffers just before exiting to
userspace. Also add sysfs reporting and cmdline parameter
"reg_file_data_sampling" to control the mitigation.
For details see:
Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/cpu.h')
| -rw-r--r-- | include/linux/cpu.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h index eb768a866fe3..59dd421a8e35 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -75,6 +75,8 @@ extern ssize_t cpu_show_spec_rstack_overflow(struct device *dev, struct device_attribute *attr, char *buf); extern ssize_t cpu_show_gds(struct device *dev, struct device_attribute *attr, char *buf); +extern ssize_t cpu_show_reg_file_data_sampling(struct device *dev, + struct device_attribute *attr, char *buf); extern __printf(4, 5) struct device *cpu_device_create(struct device *parent, void *drvdata, |