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| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2024-01-24 04:55:21 +0100 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2024-10-22 00:05:43 +0200 |
| commit | 3267cb6d3a174ff83d6287dcd5b0047bbd912452 (patch) | |
| tree | 3012a2225e382fbad6c7bfe628288acde710f9d8 /arch/x86/Kconfig | |
| parent | x86/apic: Always explicitly disarm TSC-deadline timer (diff) | |
| download | linux-3267cb6d3a174ff83d6287dcd5b0047bbd912452.tar.xz linux-3267cb6d3a174ff83d6287dcd5b0047bbd912452.zip | |
x86/lam: Disable ADDRESS_MASKING in most cases
Linear Address Masking (LAM) has a weakness related to transient
execution as described in the SLAM paper[1]. Unless Linear Address
Space Separation (LASS) is enabled this weakness may be exploitable.
Until kernel adds support for LASS[2], only allow LAM for COMPILE_TEST,
or when speculation mitigations have been disabled at compile time,
otherwise keep LAM disabled.
There are no processors in market that support LAM yet, so currently
nobody is affected by this issue.
[1] SLAM: https://download.vusec.net/papers/slam_sp24.pdf
[2] LASS: https://lore.kernel.org/lkml/20230609183632.48706-1-alexander.shishkin@linux.intel.com/
[ dhansen: update SPECULATION_MITIGATIONS -> CPU_MITIGATIONS ]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/5373262886f2783f054256babdf5a98545dc986b.1706068222.git.pawan.kumar.gupta%40linux.intel.com
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2852fcd82cbd..16354dfa6d96 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2257,6 +2257,7 @@ config RANDOMIZE_MEMORY_PHYSICAL_PADDING config ADDRESS_MASKING bool "Linear Address Masking support" depends on X86_64 + depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS help Linear Address Masking (LAM) modifies the checking that is applied to 64-bit linear addresses, allowing software to use of the |