[PATCH 01/17] x86/efi: Drop EFI stub .bss from .data section

Ard Biesheuvel
2023-08-18T13:45:21Z

Now that the EFI stub always zero inits its BSS section upon entry,
there is no longer a need to place the BSS symbols carried by the stub
into the .data section.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/boot/compressed/vmlinux.lds.S | 1 -
drivers/firmware/efi/libstub/Makefile | 7 -------
2 files changed, 8 deletions(-)

diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
index b22f34b8684a725b..4ff6ab1b67d9b336 100644
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -47,7 +47,6 @@ SECTIONS
_data = . ;
*(.data)
*(.data.*)
- *(.bss.efistub)
_edata = . ;
}
. = ALIGN(L1_CACHE_BYTES);
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index ae8874401a9f1490..8302ba66ef0b3d45 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -108,13 +108,6 @@ lib-y := $(patsubst %.o,%.stub.o,$(lib-y))
# https://bugs.llvm.org/show_bug.cgi?id=46480
STUBCOPY_FLAGS-y += --remove-section=.note.gnu.property

-#
-# For x86, bootloaders like systemd-boot or grub-efi do not zero-initialize the
-# .bss section, so the .bss section of the EFI stub needs to be included in the
-# .data section of the compressed kernel to ensure initialization. Rename the
-# .bss section here so it's easy to pick out in the linker script.
-#
-STUBCOPY_FLAGS-$(CONFIG_X86) += --rename-section .bss=.bss.efistub,load,alloc
STUBCOPY_RELOC-$(CONFIG_X86_32) := R_386_32
STUBCOPY_RELOC-$(CONFIG_X86_64) := R_X86_64_64

--
2.39.2