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0f672809f9
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 <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/231591d9122d282402d8f53175134f8db5b3bc73.1452561752.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>