Re: [PATCH v5] arm64: smccc: Support SMCCC v1.3 SVE register saving hint
From: Will Deacon <will@kernel.org>
Date: 2021-06-01 18:33:40
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:quoted
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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel