On Tue, Apr 27, 2021 at 01:47:19PM -0700, Yu-cheng Yu wrote:

From: "H.J. Lu" <redacted>

ENDBR is a special new instruction for the Indirect Branch Tracking (IBT)
component of CET.  IBT prevents attacks by ensuring that (most) indirect
branches and function calls may only land at ENDBR instructions.  Branches
that don't follow the rules will result in control flow (#CF) exceptions.

ENDBR is a noop when IBT is unsupported or disabled.  Most ENDBR
instructions are inserted automatically by the compiler, but branch
targets written in assembly must have ENDBR added manually.

Add that to __kernel_vsyscall entry point.

Signed-off-by: H.J. Lu <redacted>

Reviewed-by: Kees Cook <redacted>

-- 
Kees Cook