Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx> writes: > On 08/05/2018 13:04, Punit Agrawal wrote: >> Hi Laurent, >> >> Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx> writes: >> >>> Set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT which turns on the >>> Speculative Page Fault handler when building for 64bit. >>> >>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >>> Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx> >>> --- >>> arch/x86/Kconfig | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >>> index d8983df5a2bc..ebdeb48e4a4a 100644 >>> --- a/arch/x86/Kconfig >>> +++ b/arch/x86/Kconfig >>> @@ -30,6 +30,7 @@ config X86_64 >>> select MODULES_USE_ELF_RELA >>> select X86_DEV_DMA_OPS >>> select ARCH_HAS_SYSCALL_WRAPPER >>> + select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT >> >> I'd suggest merging this patch with the one making changes to the >> architectural fault handler towards the end of the series. >> >> The Kconfig change is closely tied to the architectural support for SPF >> and makes sense to be in a single patch. >> >> If there's a good reason to keep them as separate patches, please move >> the architecture Kconfig changes after the patch adding fault handler >> changes. >> >> It's better to enable the feature once the core infrastructure is merged >> rather than at the beginning of the series to avoid potential bad >> fallout from incomplete functionality during bisection. > > Indeed bisection was the reason why Andrew asked me to push the configuration > enablement on top of the series (https://lkml.org/lkml/2017/10/10/1229). The config options have gone through another round of splitting (between core and architecture) since that comment. I agree that it still makes sense to define the core config - CONFIG_SPECULATIVE_PAGE_FAULT early on. Just to clarify, my suggestion was to only move the architecture configs further down. > > I also think it would be better to have the architecture enablement in on patch > but that would mean that the code will not be build when bisecting without the > latest patch adding the per architecture code. I don't see that as a problem. But if I'm in the minority, I am OK with leaving things as they are as well. Thanks, Punit
