[PATCH v5] arm64: smccc: Support SMCCC v1.3 SVE register saving hint

[Will Deacon]

On Tue, Jun 01, 2021 at 07:20:58PM +0100, Will Deacon wrote:
> On Tue, 1 Jun 2021 14:04:19 +0100, Mark Brown wrote:
> > SMCCC v1.2 requires that all SVE state be preserved over SMC calls which
> > introduces substantial overhead in the common case where there is no SVE
> > state in the registers. To avoid this SMCCC v1.3 introduces a flag which
> > allows the caller to say that there is no state that needs to be preserved
> > in the registers. Make use of this flag, setting it if the SMCCC version
> > indicates support for it and the TIF_ flags indicate that there is no live
> > SVE state in the registers, this avoids placing any constraints on when
> > SMCCC calls can be done or triggering extra saving and reloading of SVE
> > register state in the kernel.
> > 
> > [...]
> 
> Applied to arm64 (for-next/smccc), thanks!
> 
> [1/1] arm64: smccc: Support SMCCC v1.3 SVE register saving hint
>       https://git.kernel.org/arm64/c/0a284a999fed

Bah, this doesn't build with allmodconfig:

WARNING: modpost: EXPORT symbol "__smccc_sve_check" [vmlinux] version generation failed, symbol will not be versioned.
aarch64-linux-gnu-ld: arch/arm64/kernel/smccc-call.o: relocation R_AARCH64_ABS32 against `__crc___smccc_sve_check' can not be used when making a shared object
make: *** [Makefile:1191: vmlinux] Error 1

/me drops the patch again

Will