This is a note to let you know that I've just added the patch titled
x86/boot: Define setup size in linker script
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-boot-define-setup-size-in-linker-script.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 093ab258e3fb1d1d3afdfd4a69403d44ce90e360 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
Date: Fri, 15 Sep 2023 17:16:27 +0000
Subject: x86/boot: Define setup size in linker script
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
commit 093ab258e3fb1d1d3afdfd4a69403d44ce90e360 upstream.
The setup block contains the real mode startup code that is used when
booting from a legacy BIOS, along with the boot_params/setup_data that
is used by legacy x86 bootloaders to pass the command line and initial
ramdisk parameters, among other things.
The setup block also contains the PE/COFF header of the entire combined
image, which includes the compressed kernel image, the decompressor and
the EFI stub.
This PE header describes the layout of the executable image in memory,
and currently, the fact that the setup block precedes it makes it rather
fiddly to get the right values into the right place in the final image.
Let's make things a bit easier by defining the setup_size in the linker
script so it can be referenced from the asm code directly, rather than
having to rely on the build tool to calculate it. For the time being,
add 64 bytes of fixed padding for the .reloc and .compat sections - this
will be removed in a subsequent patch after the PE/COFF header has been
reorganized.
This change has no impact on the resulting bzImage binary when
configured with CONFIG_EFI_MIXED=y.
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230915171623.655440-13-ardb@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/boot/header.S | 2 +-
arch/x86/boot/setup.ld | 4 ++++
arch/x86/boot/tools/build.c | 6 ------
3 files changed, 5 insertions(+), 7 deletions(-)
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -231,7 +231,7 @@ sentinel: .byte 0xff, 0xff /* Use
.globl hdr
hdr:
-setup_sects: .byte 0 /* Filled in by build.c */
+ .byte setup_sects - 1
root_flags: .word ROOT_RDONLY
syssize: .long 0 /* Filled in by build.c */
ram_size: .word 0 /* Obsolete */
--- a/arch/x86/boot/setup.ld
+++ b/arch/x86/boot/setup.ld
@@ -39,6 +39,10 @@ SECTIONS
.signature : {
setup_sig = .;
LONG(0x5a5aaa55)
+
+ /* Reserve some extra space for the reloc and compat sections */
+ setup_size = ALIGN(ABSOLUTE(.) + 64, 512);
+ setup_sects = ABSOLUTE(setup_size / 512);
}
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -48,12 +48,7 @@ typedef unsigned int u32;
u8 buf[SETUP_SECT_MAX*512];
#define PECOFF_RELOC_RESERVE 0x20
-
-#ifdef CONFIG_EFI_MIXED
#define PECOFF_COMPAT_RESERVE 0x20
-#else
-#define PECOFF_COMPAT_RESERVE 0x0
-#endif
static unsigned long efi_pe_entry;
static unsigned long efi32_pe_entry;
@@ -388,7 +383,6 @@ int main(int argc, char ** argv)
#endif
/* Patch the setup code with the appropriate size parameters */
- buf[0x1f1] = setup_sectors-1;
put_unaligned_le32(sys_size, &buf[0x1f4]);
update_pecoff_text(setup_sectors * 512, i + (sys_size * 16));
Patches currently in stable-queue which might be from ardb@xxxxxxxxxx are
queue-6.6/x86-boot-increase-section-and-file-alignment-to-4k-512.patch
queue-6.6/x86-boot-derive-file-size-from-_edata-symbol.patch
queue-6.6/x86-boot-construct-pe-coff-.text-section-from-assembler.patch
queue-6.6/x86-boot-split-off-pe-coff-.data-section.patch
queue-6.6/kallsyms-ignore-armv4-thunks-along-with-others.patch
queue-6.6/x86-efi-drop-alignment-flags-from-pe-section-headers.patch
queue-6.6/x86-boot-drop-references-to-startup_64.patch
queue-6.6/x86-efistub-use-1-1-file-memory-mapping-for-pe-coff-.compat-section.patch
queue-6.6/x86-boot-drop-pe-coff-.reloc-section.patch
queue-6.6/x86-boot-set-efi-handover-offset-directly-in-header-asm.patch
queue-6.6/x86-efi-drop-efi-stub-.bss-from-.data-section.patch
queue-6.6/x86-efi-disregard-setup-header-of-loaded-image.patch
queue-6.6/x86-boot-grab-kernel_info-offset-from-zoffset-header-directly.patch
queue-6.6/x86-boot-drop-redundant-code-setting-the-root-device.patch
queue-6.6/x86-boot-remove-the-bugger-off-message.patch
queue-6.6/x86-boot-omit-compression-buffer-from-pe-coff-image-memory-footprint.patch
queue-6.6/x86-boot-define-setup-size-in-linker-script.patch
