ddfd7ca99e
[ Upstream commit 8192a1b3807510d0ed5be1f8988c08f8d41cced9 ] Gcc recently implemented an optimization [1] for loading symbols without explicit alignment, aligning with the IBM Z ELF ABI. This ABI mandates symbols to reside on a 2-byte boundary, enabling the use of the larl instruction. However, kernel linker scripts may still generate unaligned symbols. To address this, a new -munaligned-symbols option has been introduced [2] in recent gcc versions. [1] https://gcc.gnu.org/pipermail/gcc-patches/2023-June/622872.html [2] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/625986.html However, when -munaligned-symbols is used in vdso code, it leads to the following compilation error: `.data.rel.ro.local' referenced in section `.text' of arch/s390/kernel/vdso64/vdso64_generic.o: defined in discarded section `.data.rel.ro.local' of arch/s390/kernel/vdso64/vdso64_generic.o vdso linker script discards .data section to make it lightweight. However, -munaligned-symbols in vdso object files references literal pool and accesses _vdso_data. Hence, compile vdso code without -munaligned-symbols. This means in the future, vdso code should deal with alignment of newly introduced unaligned linker symbols. Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Link: https://lore.kernel.org/r/20240219132734.22881-2-sumanthk@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Stable-dep-of: 10f705253651 ("s390/vdso: Generate unwind information for C modules") Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.