Re: [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx
From: Mark Brown <broonie@kernel.org>
Date: 2021-03-19 17:00:01
Also in:
kvm, kvmarm
On Fri, Mar 19, 2021 at 04:51:46PM +0000, Marc Zyngier wrote:
On 2021-03-19 16:42, Mark Brown wrote:
quoted
Do compilers actually do much better with this than with a static inline like the other functions in this header? Seems like something they should be figuring out.
It's not about performance or anything of the sort: in most cases where we end-up using this, it is on the back of an exception. So performance is the least of our worries.
However, the "reg" parameter to read/write_sysreg_s() cannot be a variable, because it is directly fed to the assembler. If you want to use functions, you need to specialise them per register. At this point, I'm pretty happy with a #define.
Ah, that makes sense - it was more of a "that's weird" than "that's actually a problem", hence the Reviwed-by.