linux-kernel - [tip: x86/boot] x86/efi: Drop EFI stub .bss from .data section

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Date:   Fri, 15 Sep 2023 09:37:49 -0000
From:   "tip-bot2 for Ard Biesheuvel" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Ard Biesheuvel <ardb@...nel.org>, Ingo Molnar <mingo@...nel.org>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/boot] x86/efi: Drop EFI stub .bss from .data section

The following commit has been merged into the x86/boot branch of tip:

Commit-ID:     5f51c5d0e905608ba7be126737f7c84a793ae1aa
Gitweb:        https://git.kernel.org/tip/5f51c5d0e905608ba7be126737f7c84a793ae1aa
Author:        Ard Biesheuvel <ardb@...nel.org>
AuthorDate:    Tue, 12 Sep 2023 09:00:52 
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Fri, 15 Sep 2023 11:18:40 +02:00

x86/efi: Drop EFI stub .bss from .data section

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@...nel.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20230912090051.4014114-18-ardb@google.com
---
 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 b22f34b..4ff6ab1 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 a1157c2..ef4c12f 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