621ccf8a97
The linker can make relocation entries of a symbol which has a value
of zero point to the undefined symbol entry. It is permitted since
when the symbol value is zero as the documentation of the relocation
entry `r_info' field states:
"If the index is STN_UNDEF, the undefined symbol index, the relocation
uses 0 as the symbol value."
The ELF binary does not really have any missing symbols. It is an
optimization as the symbol points to the undefined symbol because its
value is zero.
A typical way to hit this cbfstool limitation is to define an empty
region using the REGION macro in the linker script. Here is an
example if we assume `CONFIG_MY_REGION' is set to 0:
.car.data {
[...]
REGION(my_region, CONFIG_MY_REGION_SIZE)
[...]
}
A region is defined as follow:
#define REGION_SIZE(name) ((size_t)_##name##_size)
#define DECLARE_REGION(name) \
extern u8 _##name[]; \
extern u8 _e##name[]; \
extern u8 _##name##_size[];
So the size of the region is actually the address of the
`_##name##_size' symbol. Therefore, the `_my_region_size' symbol
address is zero and the linker can make the relocation entry of this
symbol point to the undefined symbol index.
In such a situation, cbfstool hits a segmentation fault when it
attempts to relocate the symbol in `parse_elf_to_xip_stage()'
function. We resolves this issue by making cbfstool skips relocation
entries pointing to the undefined symbol similarly to the way it skips
relocation relative to absolute symbols. A symbol which value is zero
can be considered an absolute symbol and therefore should not be
relocated.
Of course, we could argue that we could just prevent the declaration
of an empty region as illustrated in the following example:
.car.data {
[...]
#if CONFIG_MY_REGION_SIZE > 0
REGION(my_region, CONFIG_MY_REGION_SIZE)
#endif
[...]
}
However, this is not a satisfying solution because:
1. It requires to add unnecessary code in the linker script as an empty
region is a valid declaration. Such a workaround requires the code
using it to mark the region symbols as weak symbols to handle the
situation where the region is not defined.
2. There could be other situations which have yet to be uncovered which
would lead the same cbfstool crash.
3. A binary with an empty region is a valid ELF file and cbfstool
should not crash when it is asked to create an eXecute-In-Place stage
out of it.
Change-Id: I2803fd3e96e7ff7a0b22d72d50bfbce7acaeb941
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77699
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
|
||
|---|---|---|
| .. | ||
| abuild | ||
| acpi | ||
| amdfwtool | ||
| amdtools | ||
| apcb | ||
| archive | ||
| autoport | ||
| bincfg | ||
| board_status | ||
| bucts | ||
| cavium | ||
| cbfstool | ||
| cbmem | ||
| chromeos | ||
| coreboot-configurator | ||
| crossgcc | ||
| docker | ||
| dtd_parser | ||
| ectool | ||
| exynos | ||
| find_usbdebug | ||
| futility | ||
| fuzz-tests | ||
| genbuild_h | ||
| gitconfig | ||
| goswid@567a1c99b0 | ||
| ifdtool | ||
| intelmetool | ||
| intelp2m | ||
| inteltool | ||
| intelvbttool | ||
| ipqheader | ||
| kbc1126 | ||
| kconfig | ||
| lint | ||
| liveiso | ||
| mainboard | ||
| marvell | ||
| me_cleaner | ||
| mma | ||
| msrtool | ||
| mtkheader | ||
| nixshell | ||
| nvidia | ||
| nvramtool | ||
| pmh7tool | ||
| post | ||
| qemu | ||
| qualcomm | ||
| release | ||
| riscv | ||
| rockchip | ||
| sconfig | ||
| scripts | ||
| showdevicetree | ||
| spd_tools | ||
| spdtool | ||
| spkmodem_recv | ||
| superiotool | ||
| supermicro | ||
| testing | ||
| uio_usbdebug | ||
| util_readme | ||
| vboot_list | ||
| vgabios | ||
| x86 | ||
| xcompile | ||
| README.md | ||
README.md
- abuild - coreboot autobuild script builds coreboot images for all
available targets.
bash - acpi - Walk through all ACPI tables with their addresses.
bash - amdfwtool - Create AMD Firmware combination
C - amdtools Various tools for AMD processors
- update_efs_spi_speed - Change SPI speed in binary.
Bash - Tools to compare extended K8 memory settings.
- k8-compare-pci-space.pl - Shows differences between values
in PCI space and the default value.
Perl - k8-interpret-extended-memory-settings.pl - Shows
differences between memory controller values and the default value.
Perl - k8-read-mem-settings.sh - Makes data files understood by
the k8-interpret-extended-memory-settings script.
Bash - parse-bkdg.pl - Make bkdg.data file used by above scripts.
Perl - example_input - Sample input for the above scripts.
Text
- update_efs_spi_speed - Change SPI speed in binary.
- apcb - AMD PSP Control Block tools
- apcb_edit.py - This tool allows patching an existing APCB
binary with specific SPDs and GPIO selection pins.
Python3 - apcb_v3_edit.py - This tool allows patching an existing
APCB v3 binary with up to 16 specific SPDs.
Python3
- apcb_edit.py - This tool allows patching an existing APCB
binary with specific SPDs and GPIO selection pins.
- archive - Concatenate files and create an archive
C - autoport - Automated porting coreboot to Sandy Bridge/Ivy Bridge
platforms
Go - bincfg - Compiler/Decompiler for data blobs with specs
LexYacc - board_status - Tools to collect logs and upload them to the board
status repository
BashGo - bucts - A tool to manipulate the BUC.TS bit on Intel targets.
C - cavium - Devicetree_convert Tool to convert a DTB to a static C
file
Python - cbfstool
- cbfstool - For manipulating CBFS file
C - fmaptool - Converts plaintext fmd files into fmap blobs
C - rmodtool - Creates rmodules
C - ifwitool - For manipulating IFWI
C
- cbfstool - For manipulating CBFS file
- cbmem - CBMEM parser to read e.g. timestamps and console log
C - chromeos - These scripts can be used to access ChromeOS
resources, for example to extract System Agent reference code and other
blobs (e.g. mrc.bin, refcode, VGA option roms) from a ChromeOS recovery
image.
C - crossgcc - A cross toolchain builder for -elf toolchains (ie. no
libc support)
Bash - docker - Dockerfiles for coreboot-sdk, coreboot-jenkins-node,
coreboot.org-status and docs.coreboot.org
Make - dtd_parser - DTD structure parser
Python2 - ectool - Dumps the RAM of a laptop's Embedded/Environmental
Controller (EC).
C - exynos - Computes and fills Exynos ROM checksum (for BL1 or BL2).
Python3 - find_usbdebug - Help find USB debug ports
Bash - futility - Firmware utility for signing ChromeOS images
Make - fuzz-tests - Create test cases that crash the jpeg code.
C - genbuild_h - Generate build system definitions
Shell - gitconfig - Initialize git repository submodules install git
hooks
Bash - ifdtool - Extract and dump Intel Firmware Descriptor information
C - intelmetool - Dump interesting things about Management Engine
even if hidden
C - intelp2m - convert the configuration DW0/1 registers value from
an inteltool dump to coreboot macros.
go - inteltool - Provides information about the Intel CPU/chipset
hardware configuration (register contents, MSRs, etc).
C - intelvbttool - Parse VBT from VGA BIOS
C - ipqheader
- createxbl.py - Concatenates XBL segments into one ELF image
Python - ipqheader.py - Returns a packed MBN header image with the
specified base and size
Python - mbncat.py - Generate ipq8064 uber SBL
Python - mbn_tools.py - Contains all MBN Utilities for image
generation
Python
- createxbl.py - Concatenates XBL segments into one ELF image
- kbc1126 - Tools used to dump the two blobs from the factory
firmware of many HP laptops with 8051-based SMSC KBC1098/KBC1126
embedded controller and insert them to the firmware image.
C - kconfig - Build system
Make - lint - Source linter and linting rules
Shell - nixos - A script and NixOS configuration files to create an ISO
image for testing purposes and for working on firmware.
Bash - mainboard - mainboard specific scripts
- google - Directory for google mainboard specific scripts
- marvell - Add U-Boot boot loader for Marvell ARMADA38X
C - me_cleaner - Tool for
partial deblobbing of Intel ME/TXE firmware images
Python - mma - Memory Margin Analysis automation tests
Bash - msrtool - Dumps chipset-specific MSR registers.
C - mtkheader - Generate MediaTek bootload header.
Python3 - nvidia - nvidia blob parsers
- nvramtool - Reads and writes coreboot parameters and displaying
information from the coreboot table in CMOS/NVRAM.
C - pmh7tool - Dumps, reads and writes PMH7 registers on Lenovo
ThinkPads. PMH7 is used for switching on and off the power of some
devices on the board such as dGPU.
C - post - Userspace utility that can be used to test POST cards.
C - qemu - Makefile & comprehensive default config for QEMU Q35
emulation
Make - qualcomm - CMM script to debug Qualcomm coreboot environments.
CMM - release - Generate coreboot release
Bash - riscv
- make-spike-elf.sh - Converts a flat file into an ELF, that
can be passed to SPIKE, the RISC-V reference emulator.
Bash - sifive-gpt.py - Wraps the bootblock in a GPT partition for
SiFive's bootrom.
Python3
- make-spike-elf.sh - Converts a flat file into an ELF, that
can be passed to SPIKE, the RISC-V reference emulator.
- rockchip - Generate Rockchip idblock bootloader.
Python3 - sconfig - coreboot device tree compiler
LexYacc - scripts
- config - Manipulate options in a .config file from the
command line
Bash - cross-repo-cherrypick - Pull in patches from another tree
from a gerrit repository.
Shell - decode_spd.sh - Decodes Serial Presence Detect (SPD) files
into various human readable formats.
Bash - dts-to-fmd.sh -Converts a depthcharge fmap.dts into an
fmaptool compatible .fmd format
Bash - find-unused-kconfig-symbols.sh - Points out Kconfig
variables that may be unused. There are some false positives, but it
serves as a starting point
Shell - gerrit-rebase - Applies all commits that from-branch has
over to-branch, based on a common ancestor and gerrit meta-data
Bash - get_maintainer.pl - Print selected MAINTAINERS information
for the files modified in a patch or for a file
Perl - maintainers.go - Build subsystem Maintainers
Go - no-fsf-addresses.sh - Removes various FSF addresses from
license headers
Shell - parse-maintainers.pl - Script to alphabetize MAINTAINERS
file
Perl - rm_unused_code - Remove all code not used for a platform
from the local git repository for auditing or release
Bash - show_platforms.sh - Makes a list of platforms in the tree.
Does not show variants.
Shell - ucode_h_to_bin.sh - Microcode conversion tool
Bash - update_submodules - Check all submodules for updates
Bash
- config - Manipulate options in a .config file from the
command line
- showdevicetree - Compile and dump the device tree
C - spdtool - Dumps SPD ROMs from a given blob to separate files
using known patterns and reserved bits. Useful for analysing firmware
that holds SPDs on boards that have soldered down DRAM.
python - spkmodem_recv - Decode spkmodem signals
C - superiotool - A user-space utility to detect Super I/O of a
mainboard and provide detailed information about the register contents
of the Super I/O.
C - supermicro - Tools for supermicro platforms
- smcbiosinfo - Generates SMC biosinfo for BMC BIOS updates
C
- smcbiosinfo - Generates SMC biosinfo for BMC BIOS updates
- testing - coreboot test targets
Make - uio_usbdebug - Debug coreboot's usbdebug driver inside a running
operating system (only Linux at this time).
C - util_readme - Creates README.md of description files in
./utilsubdirectoriesBash - vboot_list - Tools to generate a list of vboot enabled devices to
the documentation
Bash - vgabios - emulated vga driver for qemu
C - x86 - Generates 32-bit PAE page tables based on a CSV input file.
Go - xcompile - Cross compile setup
Bash