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linux/arch/x86/boot/compressed/vmlinux.lds.S
Ard Biesheuvel 3e3eabe26d x86/boot: Increase section and file alignment to 4k/512
Align x86 with other EFI architectures, and increase the section
alignment to the EFI page size (4k), so that firmware is able to honour
the section permission attributes and map code read-only and data
non-executable.

There are a number of requirements that have to be taken into account:
- the sign tools get cranky when there are gaps between sections in the
  file view of the image
- the virtual offset of each section must be aligned to the image's
  section alignment
- the file offset *and size* of each section must be aligned to the
  image's file alignment
- the image size must be aligned to the section alignment
- each section's virtual offset must be greater than or equal to the
  size of the headers.

In order to meet all these requirements, while avoiding the need for
lots of padding to accommodate the .compat section, the latter is placed
at an arbitrary offset towards the end of the image, but aligned to the
minimum file alignment (512 bytes). The space before the .text section
is therefore distributed between the PE header, the .setup section and
the .compat section, leaving no gaps in the file coverage, making the
signing tools happy.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230915171623.655440-18-ardb@google.com
2023-09-17 19:48:44 +02:00

120 lines
2.1 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
#include <asm-generic/vmlinux.lds.h>
OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT)
#undef i386
#include <asm/cache.h>
#include <asm/page_types.h>
#ifdef CONFIG_X86_64
OUTPUT_ARCH(i386:x86-64)
ENTRY(startup_64)
#else
OUTPUT_ARCH(i386)
ENTRY(startup_32)
#endif
SECTIONS
{
/* Be careful parts of head_64.S assume startup_32 is at
* address 0.
*/
. = 0;
.head.text : {
_head = . ;
HEAD_TEXT
_ehead = . ;
}
.rodata..compressed : {
*(.rodata..compressed)
}
.text : {
_text = .; /* Text */
*(.text)
*(.text.*)
*(.noinstr.text)
_etext = . ;
}
.rodata : {
_rodata = . ;
*(.rodata) /* read-only data */
*(.rodata.*)
_erodata = . ;
}
.data : ALIGN(0x1000) {
_data = . ;
*(.data)
*(.data.*)
/* Add 4 bytes of extra space for a CRC-32 checksum */
. = ALIGN(. + 4, 0x200);
_edata = . ;
}
. = ALIGN(L1_CACHE_BYTES);
.bss : {
_bss = . ;
*(.bss)
*(.bss.*)
*(COMMON)
. = ALIGN(8); /* For convenience during zeroing */
_ebss = .;
}
#ifdef CONFIG_X86_64
. = ALIGN(PAGE_SIZE);
.pgtable : {
_pgtable = . ;
*(.pgtable)
_epgtable = . ;
}
#endif
. = ALIGN(PAGE_SIZE); /* keep ZO size page aligned */
_end = .;
STABS_DEBUG
DWARF_DEBUG
ELF_DETAILS
DISCARDS
/DISCARD/ : {
*(.dynamic) *(.dynsym) *(.dynstr) *(.dynbss)
*(.hash) *(.gnu.hash)
*(.note.*)
}
.got.plt (INFO) : {
*(.got.plt)
}
ASSERT(SIZEOF(.got.plt) == 0 ||
#ifdef CONFIG_X86_64
SIZEOF(.got.plt) == 0x18,
#else
SIZEOF(.got.plt) == 0xc,
#endif
"Unexpected GOT/PLT entries detected!")
/*
* Sections that should stay zero sized, which is safer to
* explicitly check instead of blindly discarding.
*/
.got : {
*(.got)
}
ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!")
.plt : {
*(.plt) *(.plt.*)
}
ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")
.rel.dyn : {
*(.rel.*) *(.rel_*)
}
ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!")
.rela.dyn : {
*(.rela.*) *(.rela_*)
}
ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!")
}