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e242bbbb6d
The syscall wrappers use the "a0" register for two different register variables, both the first argument and the return value. Here the "ret" variable is used as both input and output while the argument register is only used as input. Clang treats the conflicting input parameters as an undefined behaviour and optimizes away the argument assignment. The code seems to work by chance for the most part today but that may change in the future. Specifically clock_gettime_fallback() fails with clockids from 16 to 23, as implemented by the upcoming auxiliary clocks. Switch the "ret" register variable to a pure output, similar to the other architectures' vDSO code. This works in both clang and GCC. Link: https://lore.kernel.org/lkml/20250602102825-42aa84f0-23f1-4d10-89fc-e8bbaffd291a@linutronix.de/ Link: https://lore.kernel.org/lkml/20250519082042.742926976@linutronix.de/ Fixes:c6b99bed6b("LoongArch: Add VDSO and VSYSCALL support") Fixes:18efd0b10e("LoongArch: vDSO: Wire up getrandom() vDSO implementation") Cc: stable@vger.kernel.org Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Yanteng Si <si.yanteng@linux.dev> Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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 reStructuredText 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.