selftests/x86: Disable the ldt_gdt_64 test for now

ldt_gdt.c relies on cross-cpu invalidation of SS to do one of
its tests.  On 32-bit builds, this works fine, but on 64-bit
builds, it only works if the kernel has proper SS sigcontext
handling for 64-bit user programs.

Since the SS fixes are currently reverted, restrict the test
case to 32 bits for now.

In principle, I could change the test to use a different segment
register, but it would be messy: CS can't point to the LDT for
64-bit code, and the other registers don't result in immediate
faults because they aren't reloaded on kernel -> user
transitions.

When we fix sigcontext (in 4.6?), we can revert this.

Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/231591d9122d282402d8f53175134f8db5b3bc73.1452561752.git.luto@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions