diff options
| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2024-03-11 12:29:43 -0700 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2024-03-11 13:13:48 -0700 |
| commit | 8076fcde016c9c0e0660543e67bff86cb48a7c9c (patch) | |
| tree | b07933926b045b08a417655be3f4310cebdbb1a6 /arch/x86/Kconfig | |
| parent | 4e42765d1be01111df0c0275bbaf1db1acef346e (diff) | |
x86/rfds: Mitigate Register File Data Sampling (RFDS)
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>
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5edec175b9bf..637e337c332e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2614,6 +2614,17 @@ config GDS_FORCE_MITIGATION If in doubt, say N. +config MITIGATION_RFDS + bool "RFDS Mitigation" + depends on CPU_SUP_INTEL + default y + help + Enable mitigation for Register File Data Sampling (RFDS) by default. + RFDS is a hardware vulnerability which affects Intel Atom CPUs. It + allows unprivileged speculative access to stale data previously + stored in floating point, vector and integer registers. + See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> + endif config ARCH_HAS_ADD_PAGES |