* Andy Lutomirski luto@kernel.org wrote:
This tests that the vsyscall entries do what they're expected to do. It also confirms that attempts to read the vsyscall page behave as expected.
If changes are made to the vsyscall code or its memory map handling, running this test in all three of vsyscall=none, vsyscall=emulate, and vsyscall=native are helpful.
(Because it's easy, this also compares the vsyscall results to their vDSO equivalents.)
Cc: stable@vger.kernel.org Signed-off-by: Andy Lutomirski luto@kernel.org
Note to KAISER backporters: please test this under all three vsyscall modes. Also, in the emulate and native modes, make sure that test_vsyscall_64 agrees with the command line or config option as to which mode you're in. It's quite easy to mess up the kernel such that native mode accidentally emulates or vice versa.
Greg, etc: please backport this to all your Meltdown-patched kernels. It'll help make sure the patches didn't regress vsyscalls.
I've added this to tip:x86/pti, that way it will end up in the linear backport range of commits.
Thanks,
Ingo