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2025-06-27LoongArch: vDSO: Correctly use asm parameters in syscall wrappersThomas Weißschuh
commit e242bbbb6d7ac7556aa1e358294dc7e3c82cc902 upstream. 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: c6b99bed6b8f ("LoongArch: Add VDSO and VSYSCALL support") Fixes: 18efd0b10e0f ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-13LoongArch: vDSO: Wire up getrandom() vDSO implementationXi Ruoyao
Hook up the generic vDSO implementation to the LoongArch vDSO data page by providing the required __arch_chacha20_blocks_nostack, __arch_get_k_vdso_rng_data, and getrandom_syscall implementations. Also wire up the selftests. Signed-off-by: Xi Ruoyao <xry111@xry111.site> Acked-by: Huacai Chen <chenhuacai@kernel.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2023-06-29LoongArch: Add support to clone a time namespaceTiezhu Yang
We can see that "Time namespaces are not supported" on LoongArch: (1) clone3 test # cd tools/testing/selftests/clone3 && make && ./clone3 ... # Time namespaces are not supported ok 18 # SKIP Skipping clone3() with CLONE_NEWTIME # Totals: pass:17 fail:0 xfail:0 xpass:0 skip:1 error:0 (2) timens test # cd tools/testing/selftests/timens && make && ./timens ... 1..0 # SKIP Time namespaces are not supported On LoongArch the current kernel does not support CONFIG_TIME_NS which depends on GENERIC_VDSO_TIME_NS, select GENERIC_VDSO_TIME_NS to enable CONFIG_TIME_NS to build kernel/time/namespace.c. Additionally, it needs to define some arch-dependent functions for the timens, such as __arch_get_timens_vdso_data(), arch_get_vdso_data() and vdso_join_timens(). At the same time, modify the layout of vvar to use one page size for generic vdso data, expand another page size for timens vdso data and assign LOONGARCH_VDSO_DATA_SIZE (maybe exceeds a page size if expand in the future) for loongarch vdso data, at last add the callback function vvar_fault() and modify stack_top(). With this patch under CONFIG_TIME_NS: (1) clone3 test # cd tools/testing/selftests/clone3 && make && ./clone3 ... ok 18 [739] Result (0) matches expectation (0) # Totals: pass:18 fail:0 xfail:0 xpass:0 skip:0 error:0 (2) timens test # cd tools/testing/selftests/timens && make && ./timens ... # Totals: pass:10 fail:0 xfail:0 xpass:0 skip:0 error:0 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-08-12LoongArch: Add vDSO syscall __vdso_getcpu()Huacai Chen
We test 20 million times of getcpu(), the real syscall version take 25 seconds, while the vsyscall version take only 2.4 seconds. Signed-off-by: Rui Wang <wangrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-06-03LoongArch: Add VDSO and VSYSCALL supportHuacai Chen
Add VDSO and VSYSCALL support (sigreturn, gettimeofday and its friends) for LoongArch. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>