Mostly a revert of commit b1def7145f ("arch: deprecate `_current`").
This commit was part of PR #80716 whose initial purpose was about providing
an architecture specific optimization for _current. The actual deprecation
was sneaked in later on without proper discussion.
The Zephyr core always used _current before and that was fine. It is quite
prevalent as well and the alternative is proving rather verbose.
Furthermore, as a concept, the "current thread" is not something that is
necessarily architecture specific. Therefore the primary abstraction
should not carry the arch_ prefix.
Hence this revert.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
The weak syscall symbols generated by gen_syscalls.py are currently
compiled in the LLEXT subsystem library, which is then linked among all
other Zephyr libraries in an unspecified order. This can cause the weak
symbols to override the actual syscall implementations, leading to
undefined behaviour.
To fix this, the currently generated file is split in two elements:
- syscall_exports_llext.c contains the EXPORT_SYMBOL directives for all
syscalls. This part can be compiled with the LLEXT library and linked
among all other Zephyr libraries, and ensures all syscalls symbols
are preserved by the linker.
- syscall_weakdefs_llext.c contains the weak definitions for all syscalls.
This file is compiled in a separate library that is linked last, so
that the weak symbols are only used if no other implementation is
available.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
`_current` is now functionally equals to `arch_curr_thread()`, remove
its usage in-tree and deprecate it instead of removing it outright,
as it has been with us since forever.
Signed-off-by: Yong Cong Sin <ycsin@meta.com>
Signed-off-by: Yong Cong Sin <yongcong.sin@gmail.com>
Some auto formatters will wrap long lines of code and insert newlines
that are part of function decls outside of arguments. This change strips
out all newlines so syscall typename regex function as expected.
Signed-off-by: Mark Inderhees <markind@meta.com>
When building an LLEXT-enabled kernel, 62b19ef65c added weak aliases
of all syscall implementation functions to a pointer to NULL, with the
assumption that LLEXT would check the required symbols at link time and
fail if any of them were found.
This check, however, is ineffective in the current implementation: the
actual address that is exported is the rather normal-looking location of
the variable containing the NULL pointer. This defeats the NULL symbol
validity checks in llext_link.c and causes the extension to crash at
runtime by jumping to a location containing a few zeroes in read-only
data memory.
This commit makes sure the alias target is actually placed at address 0
using the llext-sections.ld linker fragment, so that undefined syscall
implementations are exported as NULLs and as such properly flagged at
link time.
The test for this functionality is also updated to reflect the change.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Namespaced the generated headers with `zephyr` to prevent
potential conflict with other headers.
Introduce a temporary Kconfig `LEGACY_GENERATED_INCLUDE_PATH`
that is enabled by default. This allows the developers to
continue the use of the old include paths for the time being
until it is deprecated and eventually removed. The Kconfig will
generate a build-time warning message, similar to the
`CONFIG_TIMER_RANDOM_GENERATOR`.
Updated the includes path of in-tree sources accordingly.
Most of the changes here are scripted, check the PR for more
info.
Signed-off-by: Yong Cong Sin <ycsin@meta.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>
commit 67bb6db3f8 ("syscall: Export all emitted syscalls, enabling
them for extensions") exports all emitted syscalls, however, it does
that only for the `z_mrsh` symbols, effectively only available for
userspace. If an extension running at kernel level tries to use a
syscall, it will fail to load.
This patch fixes that by exposing the `z_impl` symbols instead. However,
this is not as straightforward as the `z_mrsh` ones. As, in their
signatures, they can basically contain any type, it's not just a matter
of emitting `EXPORT_SYMBOL(z_impl_<syscall>)`, as the compiler will
complain about the undefined types. Here, there are a few approaches.
One of them is to have the `EXPORT_SYMBOL` being generated on the same
files where the syscall is implemented - injecting it there would allow
it to access all known symbols. But changing a lot of files is
undesirable, and it was one of the nice points of first patch.
Another one would be to reconstruct - or simply use the absolute path -
for the includes where the syscalls are defined. Reconstruct the paths
seems fragile and I'm not sure using absolute paths is portable.
Finally, the approach used in this patch is to declare, on a different
generated file, all `z_impl_` symbols as `void *` - after all, only the
address (and the name) to the function is relevant to EXPORT_SYMBOL. By
living in an compilation unit that doesn't include any header which
would expose any of the syscalls, there shouldn't be any conflicts. And
to account for the possibility that a syscall is not compiled - due
being configured out via Kconfig - all those symbols are also weak
aliases to a pointer to NULL. This file is then included in
`llext_export.c` (which should naturally not include any conflicting
header).
Signed-off-by: Ederson de Souza <ederson.desouza@intel.com>
Linkable loadable extensions can only use syscalls if they are exported
via EXPORT_SYSCALL (or EXPORT_SYMBOL). Instead of enabling used syscalls
one by one, this patch exports all of them automatically via
`gen_syscalls.py`. If CONFIG_LLEXT=n, the section where the exported
symbols live is discarded, so it should be a non-op when llext is not
enabled.
This patch also removes the now redundant EXPORT_SYSCALL macro. Note
that EXPORT_SYMBOL is still useful on different situations (and is
indeed used by the code generated by `gen_syscalls.py`).
Signed-off-by: Ederson de Souza <ederson.desouza@intel.com>
The generated stubs use retval for function return value.
However, this is too generic and is going to collide with
other code. So rename those to be more specific. Note
that the double underscore is intentional to minimize
chance of being shadow variables.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
The syscall generation phase parses all header files to look
for potential syscalls, and emits all the relevant files to
enable syscalls. However, this results in all the syscall
marshalling functions being included in the final binary.
This is due to these functions being referred to inside
the dispatch list, resulting in ineffective garbage
collection during linking. Previous commits allows each
drivers and subsystems to specify which header files
containing syscalls are relevant. So this commit changes
the syscall generation to only include the syscalls needed
for the build in the syscall dispatch list and removing
various bits related to that. This allows the linker to
garbage collect unused syscall related function, and thus
reducing final binary size.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
There is no need to generate all the *_mrsh.c files for
marshalling syscall arguments when userspace is not enabled.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Disables allowing the python argparse library from automatically
shortening command line arguments, this prevents issues whereby
a new command is added and code that wrongly uses the shortened
command of an existing argument which is the same as the new
command being added will silently change script behaviour.
Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
prevent `Wundef` warnings from occurring due to
missing CONFIG_ symbols and __cplusplus.
Signed-off-by: Christoph A Schnetzler <Christoph.Schnetzler@husqvarnagroup.com>
Move scripts needed by the build system and not designed to be run
individually or standalone into the build subfolder.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
