Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [RFC PATCH v4 10/11] lib: vdso: Allow arches to override the ns shift operation | Date | Thu, 16 Jan 2020 20:57:03 +0100 |
| |
Andy Lutomirski <luto@kernel.org> writes: > On Thu, Jan 16, 2020 at 9:58 AM Christophe Leroy > > Would mul_u64_u64_shr() be a good alternative? Could we adjust it to > assume the shift is less than 32? That function exists to benefit > 32-bit arches.
We'd want mul_u64_u32_shr() for this. The rules for mult and shift are:
1 <= mult <= U32_MAX
1 <= shift <= 32
If we want to enforce a shift < 32 we need to limit that conditionally in the calculation/registration function.
Thanks,
tglx
| |