From 296650c8ac4f18e886dd2a606152c00adf527219 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 28 Aug 2025 12:22:19 +0200 Subject: [PATCH] x86/boot: Check startup code for absence of absolute relocations Invoke objtool on each startup code object individually to check for the absence of absolute relocations. This is needed because this code will be invoked from the 1:1 mapping of memory before those absolute virtual addresses (which are derived from the kernel virtual base address provided to the linker and possibly shifted at boot) are mapped. Only objects built under arch/x86/boot/startup/ have this restriction, and once they have been incorporated into vmlinux.o, this distinction is difficult to make. So force the invocation of objtool for each object file individually, even if objtool is deferred to vmlinux.o for the rest of the build. In the latter case, only pass --noabs and nothing else; otherwise, append it to the existing objtool command line. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/20250828102202.1849035-40-ardb+git@google.com --- arch/x86/boot/startup/Makefile | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/boot/startup/Makefile b/arch/x86/boot/startup/Makefile index b514f7e81332a..32737f4ab5a80 100644 --- a/arch/x86/boot/startup/Makefile +++ b/arch/x86/boot/startup/Makefile @@ -19,6 +19,7 @@ KCOV_INSTRUMENT := n obj-$(CONFIG_X86_64) += gdt_idt.o map_kernel.o obj-$(CONFIG_AMD_MEM_ENCRYPT) += sme.o sev-startup.o +pi-objs := $(patsubst %.o,$(obj)/%.o,$(obj-y)) lib-$(CONFIG_X86_64) += la57toggle.o lib-$(CONFIG_EFI_MIXED) += efi-mixed.o @@ -28,3 +29,10 @@ lib-$(CONFIG_EFI_MIXED) += efi-mixed.o # to be linked into the decompressor or the EFI stub but not vmlinux # $(patsubst %.o,$(obj)/%.o,$(lib-y)): OBJECT_FILES_NON_STANDARD := y + +# +# Invoke objtool for each object individually to check for absolute +# relocations, even if other objtool actions are being deferred. +# +$(pi-objs): objtool-enabled = 1 +$(pi-objs): objtool-args = $(if $(delay-objtool),,$(objtool-args-y)) --noabs -- 2.47.3