In the current implementation, the LLEXT linker will only apply
relocations targeting a given symbol if it has a specfic symbol type.
This is overzealous and causes issues on some platforms, as some symbols
that need to be relocated are skipped due to being of a "bad" type.
Ignore the symbol type when performing relocation to solve this problem,
but also add checks to ensure we don't attempt to relocate symbols with
an invalid section index. If such a relocation is found, return an error
instead of ignoring the relocation entry to ensure that it is impossible
to execute code from a (partially) unrelocated LLEXT.
Also remove all hacks added to circumvent this issue:
* qemu_cortex_r5 exclusion from test cases
* unnecessary exclusion of some flags when building with LLEXT EDK
Fixes#72832.
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>
When building partially linked / relocatable objects no ELF segments
are created and it becomes more difficult to predict which sections
the compiler will build and use. In this case a .data.rel.local
section is created by the compiler and it is needed to link .rodata
strings in a twister test. We can handle arbitrary sections at run-
time if .peek() is supported. If it isn't we need to allocate and
copy the section. For now we simply error out in such cases. Fixing
that would represent a larger change and can be done incrementally.
This also fixes the relocation calculation to point to the correct
symbol address instead of the memory location, where it's currently
residing, because that can be a temporary buffer as is the case with
SOF.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
These relocations are needed e.g. when an LLEXT is built from
multiple files and they share data objects.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Returned values are copies, so trying to "const" return values cannot
have any effect.
Fixes the following compiler warning:
```
llext.h:165: warning: type qualifiers ignored on function return type
```
Fixes commit 41e0a4a371 ("llext: Linkable loadable extensions")
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
Adds support for all relocation type produced by GCC
on ARM platform using partial linking (-r flag) or
shared link (-fpic and -shared flag).
Signed-off-by: Cedric Lescop <cedric.lescop@se.com>
Some toolchains cannot create shared objects for Xtensa, with them we
have to use relocatable objects. Add support for them to llext.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
In addition to flushing the dcache, to ensure that the new code is
actually read by the CPU when loading an extension, the icache must
be invalidated as well.
Without this, some tests are failing in hardware because the CPU is
executing stale code from its instruction cache.
Fixes#70906 on arduino_giga_r1/stm32h747xx/m7.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
The opval argument of arch_elf_relocate() was modified by
adding the value stored at opaddr before passing it to
arch_elf_relocate(). This presumed that the addend would
always be stored as a raw value at opaddr, which is not the
case for all relocation types.
This PR modifies opval to be the absolute address of opval,
and moves the addition of the addend from llext_link_plt()
to the implementation of arch_elf_relocate().
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
Fixes commit a9a82d557c ("llext: use elf_rela_t instead of elf_rel_t")
Also switch sign of (unused?) `r_addend` to unsigned.
https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.reloc.html
Issue found thanks to the following warnings when compiling in 64bits:
```
/__w/zephyr/zephyr/include/zephyr/llext/elf.h:349:29: error:
right shift count >= width of type [-Werror=shift-count-overflow]
349 | #define ELF64_R_SYM(i) ((i) >> 32)
```
The name `elf64_word` was admittedly confusing.
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
Note `elf64_addr` and friends are defined as uint64_t which is defined
as `long long unsigned` which is for some reason different from
`size_t`. So they all require a cast.
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
Sets up memory partitions and allows for the partitions to be added to a
memory domain after loading an extension. This allows for applying
memory protection attributes to all of the needed memory regions an
extension requires to execute code correctly.
Currently only works when usermode is enabled as otherwise memory
protection APIs are unavailable.
Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
clangd like to automatically add include directives, this one slipped by
and made its way in the tree. Remove it.
Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
The only difference in the two enums are some entries related to
relocation sections. However, these entries are not used in the
code, so they can be safely removed, along with the mapping function.
Use LLEXT_MEM_* to avoid confusion with low-level "section" names.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
The arch_* functions are architecture-specific and may not be defined in
all targets. Use the global alias defined in the Cache API instead.
Fixes#66382.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
On architectures that have separate data and instruction caches, such as
the Cortex-M7, it is required to flush the reloc changes to the actual RAM
storage before trying to execute any code from the newly loaded llext.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
It is not safe to assume that on entry to llext_load, *ext contains
either NULL or a previous reference to the same ext being loaded. For
example, the shell sample was passing an uninitialized value.
Initialize *ext from a search of the llext by name. If NULL, it is the
first instance of this llext (and on load error, it stays that way). If
not NULL, increment use count and return.
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>
a new llext object is completely initialised with zeros after
allocation, no need to additionally set members of an embedded into
it array to NULL.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
llext_list() is an exported function that returns a pointer to the
llext internal extension list. That list should only be accessible
directly inside llext, while holding a lock. Remove the function.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The llext list should be internal to llext.c, remove its scanning
from shell.c, export a function for that instead.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Use an element size explicitly when calculating the array size and
use the calculated size for memset().
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Extensions should be able to selectively export their global symbols.
Add a LL_EXTENSION_SYMBOL() macro for that. Change the present
.sym_tab to be a temporary symbol table of all global symbols in an
extensions, used only during linking for internal purposes. Add a new
.exp_tab symbol table to store symbols, exported by an extension
permanently.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
If a function fails it should release all the resources it has
managed to acquire. Fix llext_load() to free memory that it has
allocated in case of an error.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Extend the llext_load() / llext_unload() API to let it be called
repeatedly for the same extension to increment or decrement its
reference counter respectively. We use a mutex to protect the counter
and make both llext_load() and llext_unload() return the use-count to
let the caller identify when the first loading and the last unloading
took place.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Loadable modules can contain global (not "static") functions, even if
they aren't exported for use by other modules, e.g. when a module is
built from multiple .c files. Such functions are then also included
in link tables and have to be re-linked.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
llext_seek(), llext_read() and llext_peek() are needed outside of the
extension code too, move them to a header.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Some applications can decide to link their loadable objects for
exactly the same addresses, where they will be loaded. In those cases
local relocations aren't needed any more and can in fact break the
object if applied while the object is in a temporary storage. Add a
parameter to skip such local relocations.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Applications can use custom ELF sections for their own purposes, add
a function for finding them.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Add support for relocating local symbols, as specified in the
.rela.dyn section.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Add support for linking PIC shared object, which only require
linking, using their PLT and GOT lists and don't need any relocation
otherwise.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Symbopl tables of ELF objects of type ET_REL contain offsets instead
of addresses as for ET_DYN.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
A common pattern is used throughout llext.c:
ext->mem[ldr->sect_map[sym.st_shndx]]
where ldr->sect_map[sym.st_shndx] actually contains indices from
enum llext_section but ext->mem[] is indexed, using enum llext_mem
values. Fix this by changing ldr->sect_map[] to actually contain
enum llext_mem values.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The symbol count in struct llext_loader is redundant, we already have
one in struct llext_symtable, accessible via struct llext. Remove the
redundant copy.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Simplify llext_copy_symbols() by using a local variable to store a
pointer.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
str_cnt in llext_find_tables() is actually used to count sections,
rename it to better match that usage.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Use .sh_entsize instead of sizeof(elf_rel_t) to make code suitable
for both REL and RELA types.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Several cosmetic changes with no change in functionality:
The pos variable in multiple functions is used as a loop variable -
it's initialised before the loop starts and then it's incremented for
each loop iteration. Move it to the loop header for readability.
"return ret" is clearer than "goto out" where the "out" label does
nothing but "out: return ret" because one sees immediately that the
function is terminated at that location with no further actions
without the need to check the "out" label.
k_heap_free(heap, NULL) is valid, no need to check the address to be
freed for NULL.
Object counters can be simple (unsigned) integers, no need to make
them size_t or elf_word.
"return 0" is simpler than "return ret" because it shows the return
value immediately without the need to check what it can be at that
location.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Try to use llext_peek() for section pointers. If it's supported and
succeeds we don't need to allocate buffers.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The only way so far to access extension images is via a memory
buffer. Since this, supposedly, will also be a rather common method,
it makes sense to add a method to access extension data quickly by
obtaining a pointer instead of copying data into local buffers. Add a
llext_peek() method for that.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
elf_rela_t contains elf_rel_t exactly and contains an additional
field at the end. Therefore pointers of that type can be used for
both types, making the code generic.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The module linking API can be used for shared objects with no
architecture-specific relocation code. Add a weak function for such
cases.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
