This is a note to let you know that I've just added the patch titled
x86/boot: Derive file size from _edata symbol
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-derive-file-size-from-_edata-symbol.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 aeb92067f6ae994b541d7f9752fe54ed3d108bcc Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
Date: Fri, 15 Sep 2023 17:16:28 +0000
Subject: x86/boot: Derive file size from _edata symbol
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
commit aeb92067f6ae994b541d7f9752fe54ed3d108bcc upstream.
Tweak the linker script so that the value of _edata represents the
decompressor binary's file size rounded up to the appropriate alignment.
This removes the need to calculate it in the build tool, and will make
it easier to refer to the file size from the header directly in
subsequent changes to the PE header layout.
While adding _edata to the sed regex that parses the compressed
vmlinux's symbol list, tweak the regex a bit for conciseness.
This change has no impact on the resulting bzImage binary when
configured with CONFIG_EFI_STUB=y.
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230915171623.655440-14-ardb@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/boot/Makefile | 2 +-
arch/x86/boot/compressed/vmlinux.lds.S | 3 +++
arch/x86/boot/header.S | 2 +-
arch/x86/boot/tools/build.c | 30 +++++++-----------------------
4 files changed, 12 insertions(+), 25 deletions(-)
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -89,7 +89,7 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vm
SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))
-sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi32_stub_entry\|efi64_stub_entry\|efi_pe_entry\|efi32_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|z_.*\)$$/\#define ZO_\2 0x\1/p'
+sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi.._stub_entry\|efi\(32\)\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_edata\|z_.*\)$$/\#define ZO_\2 0x\1/p'
quiet_cmd_zoffset = ZOFFSET $@
cmd_zoffset = $(NM) $< | sed -n $(sed-zoffset) > $@
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -47,6 +47,9 @@ SECTIONS
_data = . ;
*(.data)
*(.data.*)
+
+ /* Add 4 bytes of extra space for a CRC-32 checksum */
+ . = ALIGN(. + 4, 0x20);
_edata = . ;
}
. = ALIGN(L1_CACHE_BYTES);
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -233,7 +233,7 @@ sentinel: .byte 0xff, 0xff /* Use
hdr:
.byte setup_sects - 1
root_flags: .word ROOT_RDONLY
-syssize: .long 0 /* Filled in by build.c */
+syssize: .long ZO__edata / 16
ram_size: .word 0 /* Obsolete */
vid_mode: .word SVGA_MODE
root_dev: .word 0 /* Default to major/minor 0/0 */
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -52,6 +52,7 @@ u8 buf[SETUP_SECT_MAX*512];
static unsigned long efi_pe_entry;
static unsigned long efi32_pe_entry;
+static unsigned long _edata;
static unsigned long _end;
/*----------------------------------------------------------------------*/
@@ -308,6 +309,7 @@ static void parse_zoffset(char *fname)
while (p && *p) {
PARSE_ZOFS(p, efi_pe_entry);
PARSE_ZOFS(p, efi32_pe_entry);
+ PARSE_ZOFS(p, _edata);
PARSE_ZOFS(p, _end);
p = strchr(p, '\n');
@@ -320,7 +322,6 @@ int main(int argc, char ** argv)
{
unsigned int i, sz, setup_sectors;
int c;
- u32 sys_size;
struct stat sb;
FILE *file, *dest;
int fd;
@@ -368,24 +369,14 @@ int main(int argc, char ** argv)
die("Unable to open `%s': %m", argv[2]);
if (fstat(fd, &sb))
die("Unable to stat `%s': %m", argv[2]);
- sz = sb.st_size;
+ if (_edata != sb.st_size)
+ die("Unexpected file size `%s': %u != %u", argv[2], _edata,
+ sb.st_size);
+ sz = _edata - 4;
kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
if (kernel == MAP_FAILED)
die("Unable to mmap '%s': %m", argv[2]);
- /* Number of 16-byte paragraphs, including space for a 4-byte CRC */
- sys_size = (sz + 15 + 4) / 16;
-#ifdef CONFIG_EFI_STUB
- /*
- * COFF requires minimum 32-byte alignment of sections, and
- * adding a signature is problematic without that alignment.
- */
- sys_size = (sys_size + 1) & ~1;
-#endif
-
- /* Patch the setup code with the appropriate size parameters */
- put_unaligned_le32(sys_size, &buf[0x1f4]);
-
- update_pecoff_text(setup_sectors * 512, i + (sys_size * 16));
+ update_pecoff_text(setup_sectors * 512, i + _edata);
crc = partial_crc32(buf, i, crc);
@@ -397,13 +388,6 @@ int main(int argc, char ** argv)
if (fwrite(kernel, 1, sz, dest) != sz)
die("Writing kernel failed");
- /* Add padding leaving 4 bytes for the checksum */
- while (sz++ < (sys_size*16) - 4) {
- crc = partial_crc32_one('\0', crc);
- if (fwrite("\0", 1, 1, dest) != 1)
- die("Writing padding failed");
- }
-
/* Write the CRC */
put_unaligned_le32(crc, buf);
if (fwrite(buf, 1, 4, dest) != 4)
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
