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From: Ard Biesheuvel <ardb@google.com>
To: linux-efi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
	Evgeniy Baskov <baskov@ispras.ru>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Jones <pjones@redhat.com>,
	Matthew Garrett <mjg59@srcf.ucam.org>,
	Gerd Hoffmann <kraxel@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH v2 01/15] x86/efi: Drop EFI stub .bss from .data section
Date: Tue, 12 Sep 2023 09:00:52 +0000	[thread overview]
Message-ID: <20230912090051.4014114-18-ardb@google.com> (raw)
In-Reply-To: <20230912090051.4014114-17-ardb@google.com>

From: Ard Biesheuvel <ardb@kernel.org>

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 b22f34b8684a..4ff6ab1b67d9 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 a1157c2a7170..ef4c12f0877b 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
 
-- 
2.42.0.283.g2d96d420d3-goog


  reply	other threads:[~2023-09-12  9:02 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-12  9:00 [PATCH v2 00/15] x86/boot: Rework PE header generation Ard Biesheuvel
2023-09-12  9:00 ` Ard Biesheuvel [this message]
2023-09-12  9:00 ` [PATCH v2 02/15] x86/efi: Disregard setup header of loaded image Ard Biesheuvel
2023-09-12  9:00 ` [PATCH v2 03/15] x86/efi: Drop alignment flags from PE section headers Ard Biesheuvel
2023-09-12  9:00 ` [PATCH v2 04/15] x86/boot: Remove the 'bugger off' message Ard Biesheuvel
2023-09-12  9:00 ` [PATCH v2 05/15] x86/boot: Omit compression buffer from PE/COFF image memory footprint Ard Biesheuvel
2023-09-12  9:00 ` [PATCH v2 06/15] x86/boot: Drop redundant code setting the root device Ard Biesheuvel
2023-09-12  9:00 ` [PATCH v2 07/15] x86/boot: Grab kernel_info offset from zoffset header directly Ard Biesheuvel
2023-09-12  9:00 ` [PATCH v2 08/15] x86/boot: Drop references to startup_64 Ard Biesheuvel
2023-09-15  9:15   ` Ingo Molnar
2023-09-15 13:48     ` Ard Biesheuvel
2023-09-15 15:40       ` Ingo Molnar
2023-09-15 15:45         ` Ingo Molnar
2023-09-15 15:48           ` Ard Biesheuvel
2023-09-12  9:01 ` [PATCH v2 09/15] x86/boot: Set EFI handover offset directly in header asm Ard Biesheuvel
2023-09-12  9:01 ` [PATCH v2 10/15] x86/boot: Define setup size in linker script Ard Biesheuvel
2023-09-12  9:01 ` [PATCH v2 11/15] x86/boot: Derive file size from _edata symbol Ard Biesheuvel
2023-09-12  9:01 ` [PATCH v2 12/15] x86/boot: Construct PE/COFF .text section from assembler Ard Biesheuvel
2023-09-12  9:01 ` [PATCH v2 13/15] x86/boot: Drop PE/COFF .reloc section Ard Biesheuvel
2023-09-12  9:01 ` [PATCH v2 14/15] x86/boot: Split off PE/COFF .data section Ard Biesheuvel
2023-09-12  9:01 ` [PATCH v2 15/15] x86/boot: Increase section and file alignment to 4k/512 Ard Biesheuvel
2023-09-15  9:22 ` [PATCH v2 00/15] x86/boot: Rework PE header generation Ingo Molnar
2023-09-15 11:30   ` Ingo Molnar
2023-09-15 13:21     ` Ard Biesheuvel
2023-09-15 13:28       ` Ard Biesheuvel
2023-09-16  9:10         ` Ingo Molnar
2023-09-16 19:14           ` Ard Biesheuvel
2023-09-17 17:50             ` Ingo Molnar
2023-10-03  2:02 ` Jan Hendrik Farr
2023-10-23 11:22   ` Ard Biesheuvel
2023-10-23 17:35     ` Jan Hendrik Farr
2023-10-24  8:21       ` Dave Young
2023-10-24  8:31         ` Dave Young

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