Messages in this thread Patch in this message | | | From | Alexander Shishkin <> | Subject | [PATCH v3 10/12] x86/vsyscall: Document the fact that vsyscall=emulate disables LASS | Date | Fri, 9 Jun 2023 21:36:30 +0300 |
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Since EMULATE mode of vsyscall disables LASS, because fixing the LASS violations during the EMULATE mode would need complex instruction decoding, document this fact in kernel-parameters.txt.
Cc: Andy Lutomirski <luto@kernel.org> Suggested-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> --- Documentation/admin-guide/kernel-parameters.txt | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9e5bab29685f..efed9193107e 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6850,7 +6850,9 @@ emulate Vsyscalls turn into traps and are emulated reasonably safely. The vsyscall page is - readable. + readable. This also disables the LASS + feature to allow userspace to poke around + the vsyscall page. xonly [default] Vsyscalls turn into traps and are emulated reasonably safely. The vsyscall -- 2.39.2
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