Nathan Chancellor eb13a1ff27 random: vDSO: avoid call to memset() when zeroing reserved parameter ... After a recent change in LLVM [1], builds with the random vDSO implementation, such as PowerPC and RISC-V, fail when checking the vDSO: arch/powerpc/kernel/vdso/vdso32.so.dbg: dynamic relocations are not supported arch/riscv/kernel/vdso/vdso.so.dbg: dynamic relocations are not supported memset() is now generated when zeroing params->reserved for some builds because LLVM has an optimization (now run in more instances) that can recognize at compile time when it is assigning a static value to a contiguous area of memory and turn that into a call to memset(). Both clang and GCC assume memset() is always available [2]. Clang has an internal fiddly hook, -max-store-memset, which we can set to a high number, to disable generating out of line memset calls [3]. Similarly, GCC has -finline-stringops=memset to do the same [4], should this issue ever hit future version of GCC. While these options wouldn't make sense for normal kernel code, it is fine for the extremely limited and intentionally compact vDSO code. Link: 90cebef141 [1] Link: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Standards.html#index-ffreestanding [2] Link: b28eeb28be [3] Link: https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-finline-stringops [4] Closes: https://github.com/ClangBuiltLinux/linux/issues/2183 Cc: stable@vger.kernel.org # v6.12+ Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>		2026-10-02 12:12:13 +02:00
..
.gitignore	RISC-V: Fix the VDSO symbol generaton for binutils-2.35+	2020-11-06 00:03:48 -08:00
flush_icache.S	arch/riscv: compile vdso with landing pad and shadow stack note	2026-01-29 02:38:40 -07:00
gen_vdso_offsets.sh	arch/riscv: add dual vdso creation logic and select vdso based on hw	2026-01-29 02:38:40 -07:00
getcpu.S	arch/riscv: compile vdso with landing pad and shadow stack note	2026-01-29 02:38:40 -07:00
getrandom.c	RISC-V: vDSO: Wire up getrandom() vDSO implementation	2025-06-05 14:03:09 -07:00
hwprobe.c	Revert "riscv: hwprobe: Fix stale vDSO data for late-initialized keys at boot"	2026-08-07 19:24:30 -06:00
Makefile	random: vDSO: avoid call to memset() when zeroing reserved parameter	2026-10-02 12:12:13 +02:00
note.S	riscv: Add build salt to the vDSO	2026-06-25 12:05:05 -06:00
rt_sigreturn.S	arch/riscv: vdso: remove CFI landing pad from rt_sigreturn	2026-07-14 19:34:38 -06:00
sys_hwprobe.S	arch/riscv: compile vdso with landing pad and shadow stack note	2026-01-29 02:38:40 -07:00
vdso.lds.S	riscv: vdso: Add symbols for the alternative section boundaries	2026-08-07 19:24:33 -06:00
vdso.S	riscv: compat: vdso: Add COMPAT_VDSO base code implementation	2022-04-26 13:36:53 -07:00
vgetrandom-chacha.S	arch/riscv: compile vdso with landing pad and shadow stack note	2026-01-29 02:38:40 -07:00
vgettimeofday.c	arch: vdso: consolidate gettime prototypes	2023-11-23 11:32:32 +01:00