linux-kernel - Re: [PATCH] x86/boot: Don't add the EFI stub to targets, again

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Date: Mon, 10 Jun 2024 10:17:35 +0200
From: Ard Biesheuvel <ardb@...nel.org>
To: Benjamin Segall <bsegall@...gle.com>
Cc: linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Arvind Sankar <nivedita@...m.mit.edu>, Thomas Gleixner <tglx@...utronix.de>, 
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [PATCH] x86/boot: Don't add the EFI stub to targets, again

On Thu, 6 Jun 2024 at 23:14, Benjamin Segall <bsegall@...gle.com> wrote:
>
> This is a re-commit of the commit da05b143a308 ("x86/boot: Don't add the
> EFI stub to targets") after the tagged patch incorrectly reverted it.
>
> To summarize: vmlinux-objs-y is added to targets, with an assumption
> that they are all relative to $(obj); adding a $(objtree)/drivers/...
> path causes the build to incorrectly create a useless
> arch/x86/boot/compressed/drivers/... directory tree.
>
> Fix this just by using a different make variable for the EFI stub.
>
> Fixes: cb8bda8ad443 ("x86/boot/compressed: Rename efi_thunk_64.S to efi-mixed.S")
> Signed-off-by: Ben Segall <bsegall@...gle.com>

Oops, my bad.

Reviewed-by: Ard Biesheuvel <ardb@...nel.org>

Please add

Cc: <stable@...r.kernel.org> # v6.1+

One nit below.


> ---
>  arch/x86/boot/compressed/Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
> index 243ee86cb1b1..5245c8fedc17 100644
> --- a/arch/x86/boot/compressed/Makefile
> +++ b/arch/x86/boot/compressed/Makefile
> @@ -103,13 +103,13 @@ vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o
>  vmlinux-objs-$(CONFIG_INTEL_TDX_GUEST) += $(obj)/tdx.o $(obj)/tdcall.o $(obj)/tdx-shared.o
>  vmlinux-objs-$(CONFIG_UNACCEPTED_MEMORY) += $(obj)/mem.o
>
>  vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o
>  vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_mixed.o
> -vmlinux-objs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
> +efi-obj-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
>

I'd prefer to call this vmlinux-libs-y rather than efi-obj-y, because
static libraries and locally built objects are being treated
differently here. The other EFI related objects are added to
vmlinux-objs-y, making it entirely unintuitive why this distinction
exists.



> -$(obj)/vmlinux: $(vmlinux-objs-y) FORCE
> +$(obj)/vmlinux: $(vmlinux-objs-y) $(efi-obj-y) FORCE
>         $(call if_changed,ld)
>
>  OBJCOPYFLAGS_vmlinux.bin :=  -R .comment -S
>  $(obj)/vmlinux.bin: vmlinux FORCE
>         $(call if_changed,objcopy)
> --
> 2.45.2.505.gda0bf45e8d-goog
>