Some applications need to save LLEXT context, e.g. when suspending,
to later restore it quickly without a full relinking. Add 2 functions
for context saving and restoring. Since these functions are likely to
change in the future, put them in llext_experimental.c, which depends
on CONFIG_LLEXT_EXPERIMENTAL and is disabled by default.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Some applications require loading extensions into the memory which does
not exist during the boot time and cannot be allocated statically. Make
the application responsible for LLEXT heap allocation. Do not allocate
LLEXT heap statically.
Signed-off-by: Alex Ivanov <alexivanov@google.com>
This patch adds support for Zstd and Zip formats to the EDK generation
process. The user can now choose between XZ, Zstd, and Zip compression
and output formats for the EDK file.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Add a new Kconfig option to make the generation of an Extension
Development Kit (EDK) for the LLEXT subsystem optional. This
allows to cleanly separate EDK-related configuration and build
steps from the rest of the Zeprhyr build system.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
The new CONFIG_LLEXT_IMPORT_ALL_GLOBALS option allows all global symbols
from extensions to be used by the main application. This is useful to
load basic extensions that have been compiled without the full Zephyr
EDK.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
This new option allows to export devices using identifiers generated
from the hash of the devicetree node path, instead of the device's
ordinal number. Identifiers generated this way are stable across
rebuilds.
Add new test cases to test this new option.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Some ARC processor configurations have separate memory for code (ICCM)
and for data (DCCM). Such configurations are unsuitable for LLEXT,
except for some quite special cases. For now, disable LLEXT and its
tests for these devices completely.
Signed-off-by: Ilya Tagunov <Ilya.Tagunov@synopsys.com>
Currently when building LLEXT for Xtensa we use the -fPIC compiler
option, but this cannot be used when using detached sections in
extensions. Add a Kconfig option to switch between the two
compilation modes and switch -fPIC off when building relocatable
(partially linked) ELF binaries.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
This commit introduces architecture-specific ELF relocations for RISC-V,
in accordance with the RISC-V PSABI specification:
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc
Also, the necessary compiler configurations for compiling LLEXT
extensions on RISC-V are added, and the llext tests are executed on
RISC-V targets.
Calling llext extensions from user threads in RISC-V is still
unsupported as of this commit.
Signed-off-by: Eric Ackermann <eric.ackermann@cispa.de>
This change adds a new configuration option, LLEXT_EXPORT_DEVICES, which
enables exporting all devices defined in the device tree to llext
extensions. When enabled, all devices are made available to extensions
via the standard DT_ / DEVICE_* macros.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Adds support for all relocation type produced by GCC
on AARCH64 platform using partial linking (-r flag) or
shared link (-fpic and -shared flag).
Signed-off-by: Adam Wojasinski <awojasinski@baylibre.com>
This patch sets the default value for LLEXT_STORAGE_WRITABLE to 'y' on
the Xtensa architecture. This is necessary because it does not currently
support the read-only mode for the LLEXT storage.
Make sure the default reflects this instead of asking the user to
manually set it.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
This commit introduces support for an alternate linking method in the
LLEXT subsystem, called "SLID" (short for Symbol Link Identifier),
enabled by the CONFIG_LLEXT_EXPORT_BUILTINS_BY_SLID Kconfig option.
SLID-based linking uses a unique identifier (integer) to identify
exported symbols, instead of using the symbol name as done currently.
This approach provides several benefits:
* linking is faster because the comparison operation to determine
whether we found the correct symbol in the export table is now an
integer compare, instead of a string compare
* binary size is reduced as symbol names can be dropped from the binary
* confidentiality is improved as a side-effect, as symbol names are no
longer present in the binary
Signed-off-by: Mathieu Choplain <mathieu.choplain@st.com>
Use an existing variable instead of re-calculating and fix swapped
space and a paranthesis.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
A new Kconfig option which generates syscall stubs assuming that
extensions will always run on userspace, thus simplifying linking
them, as there's no need for z_impl_ stubs (used for direct syscalls),
CONFIG_LLEXT_EDK_USERSPACE_ONLY.
While defining __ZEPHYR_USER__ could have the same effect for optmised
builds, people building extensions on debug environments - thus
non-optimised - would suffer, as they'd need to somehow make the stubs
available (by either exporting the symbol or implementing dummy stubs).
Signed-off-by: Ederson de Souza <ederson.desouza@intel.com>
Loadable extensions need access to Zephyr (and Zephyr application)
includes and some CFLAGS to be properly built. This patch adds a new
target, `llext-edk`, which generates a tar file with those includes and
flags that can be loaded from cmake and make files.
A Zephyr application willing to expose some API to extensions it loads
only need to add the include directories describing such APIs to the
Zephyr ones via zephyr_include_directories() CMake call.
A new Kconfig option, CONFIG_LLEXT_EDK_NAME allows one to control some
aspects of the generated file, which enables some customization - think
of an application called ACME, willing to have a ACME_EXTENSION_KIT or
something.
All EDK Kconfig options are behind CONFIG_LLEXT_EDK, which doesn't
depend on LLEXT directly - so that EDK features can be leveraged by
downstream variations of loadable extensions.
Also, each arch may need different compiler flags for extensions: those
are handled by the `LLEXT_CFLAGS` cmake flag. An example is set for GCC
ARM.
Finally, EDK throughout this patch means Extension Development Kit,
which is a bad name, but at least doesn't conflict with SDK.
Signed-off-by: Ederson de Souza <ederson.desouza@intel.com>
Dynamic code execution applications not using LLEXT for "extension"
loading are subject to the same linker optimization symbol resolution
issue described in commit 321e395 (in summary, libkernel.a syscalls
not used directly by the application result in weak symbol resolution
of their z_mrsh_ wrapper).
To support usecases where an application is using alternative methods
to load and execute code calling syscalls (likely from userspace) or
is using a mechanism where the linker may not be aware, the configuration
option has been decoupled from CONFIG_LLEXT (who is now a selector) to
KERNEL_WHOLE_ARCHIVE.
Signed-off-by: Daniel Apperloo <daniel.apperloo@intel.com>
This commit adds support for building relocatable (partially linked)
ELF files as the binary object type for the llext subsystem.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Add a new Kconfig option to select the binary object type for the llext
subsystem. This will allow to fully decouple the architecture type from
the kind of binary object that is expected by the loader.
The defaults have been chosen to match the current behavior of the ARM
and Xtensa architectures, but developers can now more easily experiment
with other object types.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Targets that have a data cache must enable CACHE_MANAGEMENT to allow the
llext API to flush it when loading an extension. This patch forces the
flag to be enabled when the target has a data cache.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
When using the LLEXT buffer loader we now avoid copying extensions
from storage to allocated memory by pointing directly into the stored
image. We then also perform linking and relocation in that memory,
which modifies its contents. However, this is impossible if that
storage is read-only. Add a Kconfig flag to distinguish between
writable and read-only storage types. Also use that flag to decide,
whether the extension image in test_llext_simple.c should be defined
as const or not.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The maximum size of an extension accept by the shell
was previously a define and is now made configurable through Kconfig.
Signed-off-by: Kai Meinhard <meinhard@gessler.de>
Adds the linkable loadable extensions (llext) subsystem which provides
functionality for reading, parsing, and linking ELF encoded executable
code into a managed extension to the running elf base image.
A loader interface, and default buffer loader implementation,
make available to the llext subsystem the elf data. A simple management
API provide the ability to load and unload extensions as needed. A shell
interface for extension loading and unloading makes it easy to try.
Adds initial support for armv7 thumb built elfs with very specific
compiler flags.
Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
Co-authored-by: Chen Peng1 <peng1.chen@intel.com>
Co-authored-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
