It is safe to do SIMD in an interrupt on PowerPC. Only disable when there is no SIMD available (and this is a static branch).
Tested and works with the WireGuard (Zinc) patch I wrote that needs this. Also improves performance of the crypto subsystem that checks this. Re-sending because this linuxppc-dev didn't seem to accept it. Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=203571 Signed-off-by: Shawn Landden <sh...@git.icu> --- arch/powerpc/include/asm/simd.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 arch/powerpc/include/asm/simd.h diff --git a/arch/powerpc/include/asm/simd.h b/arch/powerpc/include/asm/simd.h new file mode 100644 index 000000000..b3fecb95a --- /dev/null +++ b/arch/powerpc/include/asm/simd.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +#include <asm/cpu_has_feature.h> + +/* + * may_use_simd - whether it is allowable at this time to issue SIMD + * instructions or access the SIMD register file + * + * As documented in Chapter 6.2.1 Machine Status Save/Restore Registers + * of Power ISA (2.07 and 3.0), all registers are saved/restored in an interrupt. + */ +static inline bool may_use_simd(void) +{ + return !cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE); +} -- 2.21.0.1020.gf2820cf01a