x86/extable: Remove EX_TYPE_FAULT from MCE safe fixups

Now that the MC safe copy and FPU have been converted to use the MCE safe
fixup types remove EX_TYPE_FAULT from the list of types which MCE considers
to be safe to be recovered in kernel.

This removes the SGX exception handling of ENCLS from the #MC safe
handling, but according to the SGX wizards the current SGX implementations
cannot survive #MC on ENCLS:

  https://lore.kernel.org/r/YS+upEmTfpZub3s9@google.com

The code relies on the trap number being stored if ENCLS raised an
exception. That's still working, but it does no longer trick the MCE code
into assuming that #MC is handled correctly for ENCLS.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210908132525.445255957@linutronix.de

diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index d9b77a74f8d2e3100793a69b6bbead1c813e7c03..f60bbaff9f65ef0a15884df0e609a087bd84b8db 100644 (file)
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -277,7 +277,6 @@ static int error_context(struct mce *m, struct pt_regs *regs)
                        return IN_KERNEL;
                m->kflags |= MCE_IN_KERNEL_COPYIN;
                fallthrough;
-       case EX_TYPE_FAULT:
        case EX_TYPE_FAULT_MCE_SAFE:
        case EX_TYPE_DEFAULT_MCE_SAFE:
                m->kflags |= MCE_IN_KERNEL_RECOV;