On Thu, Jan 25, 2018 at 10:31:31AM +0000, Ard Biesheuvel wrote: > Now that all UEFI runtime service wrappers ensure that byref > arguments are moved into the UEFI marshalling buffer (which > is not part of the kernel mapping), we can proceed and unmap > the kernel while UEFI runtime service calls are in progress. > > This is done by setting the EPD1 bit and flushing the TLB of > the local CPU. This makes it independent of KPTI or whether > non-global mappings are being used. One snag with this is that it will break SPE, so I'd prefer this behaviour to be predicated on kpti so that the arm64_kernel_unmapped_at_el0() check in drivers/perf/arm_spe_pmu.c remains valid. Will -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
