[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v8 1/2] x86/boot: Align mbi2.c stack to 16 bytes
On 09.10.2024 12:15, Frediano Ziglio wrote: > On Wed, Oct 9, 2024 at 9:20 AM Jan Beulich <jbeulich@xxxxxxxx> wrote: >> On 09.10.2024 10:04, Frediano Ziglio wrote: >>> --- a/xen/arch/x86/efi/Makefile >>> +++ b/xen/arch/x86/efi/Makefile >>> @@ -11,6 +11,8 @@ $(obj)/boot.init.o: $(obj)/buildid.o >>> $(call cc-option-add,cflags-stack-boundary,CC,-mpreferred-stack-boundary=4) >>> $(addprefix $(obj)/,$(EFIOBJ-y)): CFLAGS_stack_boundary := >>> $(cflags-stack-boundary) >>> >>> +$(obj)/mbi2.o: CFLAGS_stack_boundary := $(cflags-stack-boundary) >>> + >>> obj-y := common-stub.o stub.o >>> obj-$(XEN_BUILD_EFI) := $(filter-out %.init.o,$(EFIOBJ-y)) >>> obj-bin-$(XEN_BUILD_EFI) := $(filter %.init.o,$(EFIOBJ-y)) >> >> You're duplicating code, which is better to avoid when possible. Is there >> a reason the earlier commit didn't simply add mbi2.o to $(EFIOBJ-y)? That >> way the existing logic would have covered that file as well. And really I >> think it should have been mbi2.init.o (or else adding it into $(obj-bin-y) >> is wrong), which probably wants correcting at the same time (ISTR actually >> having requested that during an earlier review round). > > This was my first attempt, but it fails poorly, as EFIOBJ-y comes with > the addition of creating some file links that causes mbi2.c to be > overridden. I can't see $(EFIOBJ-y) affecting symlink creation. What I can see is that the variable is used in the setting of clean-files, which indeed is a problem. Still imo the solution then is to introduce another variable to substitute the uses of $(EFIOBJ-y) in arch/x86/efi/Makefile. E.g. EFIOBJ-all := $(EFIOBJ-y) mbi2.init.o > If I remember, you suggested changing to obj-bin-y. Still, maybe is > not the best place. It was added to obj-bin-y because it should be > included either if XEN_BUILD_EFI is "y" or not. No, that doesn't explain the addition to obj-bin-y; this would equally be achieved by adding to obj-y. The difference between the two variables is whether objects are to be subject to LTO. And the typical case then is that init-only objects aren't worth that extra build overhead. Hence the common pattern is (besides files with assembly sources) for *.init.o to be added to obj-bin-*. Jan
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