contiki/cpu/x86/quarkX1000.ld
Michael LeMay 24f23588dd x86: Fix section alignment for EFI binaries
This patch fixes the section alignment specification in the linker script for
the Intel Quark X1000 SoC so that the UEFI GenFw program generates correct EFI
binaries.  See the added comment in quarkX1000.ld for details.
2016-09-08 12:13:28 -07:00

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/*
* Copyright (C) 2015-2016, Intel Corporation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
OUTPUT_FORMAT("elf32-i386")
ENTRY(start)
SECTIONS {
/*
OS-Dev Wiki says it is common for kernels to start at 1M. Addresses before that
are used by BIOS/EFI, the bootloader and memory-mapped I/O.
The UEFI GenFw program inserts a 0x220-byte offset between the image base and
the .text section. We add that same offset here to align the symbols in the
UEFI DLL with those in the final UEFI binary to make debugging easier. We also
apply 32-byte alignments to sections rather than more conventional 4K-byte
alignments to avoid symbols being shifted from the intermediate DLL to the
final UEFI image as would occur if the GenFw program shifted the .text section
from a higher, 4K-aligned offset to the 0x220-byte offset from the image base.
Such shifting may make debugging more difficult by preventing the DLL from
being a directly-useful source of symbol information. The debugging symbols
are not included in the final UEFI image. The GenFw program uses a minimum
section alignment of 32 bytes, so smaller alignment granularities may also
result in symbol perturbation.
*/
. = 1M + 0x220;
.text : ALIGN (32)
{
KEEP(*(.multiboot))
*(.boot_text)
*(.text*)
}
/*
The alignment directive must be placed after the colon so that the desired
alignment is indicated in the ELF section metadata. This metadata is used
by the UEFI GenFw program. It is necessary to avoid specifying a smaller
alignment value in the ELF metadata for some section "B" that follows some
section "A" with an ending address that is not aligned on a 32-byte boundary.
In that case, GenFw may place section "B" at a lower starting address in the
EFI binary than section "B" had in the input ELF file. This may result in
incorrect program behavior. Note that this situation is not directly visible
in the EFI binary metadata, since GenFw combines the ELF .rodata, .data, and
.bss sections into a single .data section in the EFI binary.
*/
.rodata : ALIGN (32)
{
*(.rodata*)
_sdata_kern_startup_func = .;
KEEP(*(.kern_startup_func))
_edata_kern_startup_func = .;
_sdata_shared_isr = .;
KEEP(*(.shared_isr_data*))
_edata_shared_isr = .;
}
.data : ALIGN (32)
{
*(.data*)
}
.bss : ALIGN (32)
{
*(COMMON)
*(.main_stack)
*(.bss*)
*(.gdt_bss_start)
/*
The other GDT-related sections defined in gdt.h are only used when
protection domain support is enabled. Thus, they do not need to be
included here.
*/
_ebss_gdt_addr = .;
}
_ebss_pre_dma_addr = ALIGN(32);
}