contiki/cpu/x86/quarkX1000.ld
Michael LeMay f85654a82f x86, galileo: Add UEFI support
This patch adds support for optionally building EFI binaries in
addition to Multiboot ELF binaries.  It includes a script,
build_uefi.sh, that downloads tool and library sources from the EDK II
project, builds the GenFw tool that is used to create UEFI binaries,
and creates a makefile that is included from the main x86 common
makefile and enables UEFI support in the Contiki build system.  If the
script is not run prior to building Contiki, then an informational
message will be displayed with instructions for running build_uefi.sh
if UEFI support is desired.  This patch also adds the path to the
auto-generated makefile to .gitignore.

This patch modifies the linker script for the Intel Quark X1000 to
account for the output file section offsets and alignment expectations
of the EDK II GenFw project.

This patch also adds a newlib patch to remove the weak symbol
attribute from floating point stdio support routines.  See
<newlib>/newlib/README for an explanation of how the newlib developers
intended for _printf_float and _scanf_float to be linked.  Newlib
declares them as weak symbols with the intention that developers would
force them to be linked only when needed using a linker command line
option.  However, some but not all Contiki programs require them, so
we cannot simply always include or exclude them.  Instead, we remove
the weak symbol attributes and rely on the linker to automatically
determine whether or not they should be linked.  This avoids an issue
in which weak symbols were undefined in the intermediate DLL generated
as part of the UEFI build process.  That resulted in the GenFw program
emitting "ERROR 3000" messages when it encountered relocations
referencing such an undefined symbol.

Finally, this patch updates README.md to both make some revisions to
account for the UART support introduced in previous patches as well as
to provide instructions for using the UEFI support.
2015-12-21 08:06:14 -02:00

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/*
* Copyright (C) 2015, 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 0x240-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 0x240-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 + 0x240;
.text ALIGN (32) :
{
KEEP(*(.multiboot))
*(.text*)
}
.rodata ALIGN (32) :
{
*(.rodata*)
}
.data ALIGN (32) :
{
*(.data*)
}
.bss ALIGN (32) :
{
*(COMMON)
*(.bss*)
}
}