This reverts commit cdedb254ccddd9c6a8db91b3737690327e48dfe7. Vector length limiting via Kconfig is no longer required now that the default vector length can be manipulated at runtime via procfs. --- arch/arm64/Kconfig | 35 ----------------------------------- arch/arm64/mm/proc.S | 5 ----- 2 files changed, 40 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 98c0934..bced568 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -900,41 +900,6 @@ config ARM64_SVE To enable use of this extension on CPUs that implement it, say Y. -if ARM64_SVE - -config ARM64_SVE_FULL_VECTOR_LENGTH - bool "Enable full hardware vector length for userspace" - default n - help - SVE vector lengths greater than 512 bits impact the size of signal - frames and therefore the size requirements for any userspace stack - onto which a signal may be delivered. Using larger vector lengths - may therefore cause problems for some software. For this reason, the - kernel currently limits the maximum vector length for userspace - software to 512 bits by default. - - Enabling this option removes the limit, so that the full vector - length implemented by the hardware is made available to userspace. - - Be aware: in general, software that (a) does not use SVE (including - via libraries), or (b) does not handle signals, or (c) uses default - process/thread stack sizes and does not use sigaltstack(2) should be - unaffected by enabling larger vectors. Software that does not meet - these criteria or that relies on certain legacy uses of the ucontext - API may be affected however. - - This is a transitional compatibility option only and will be replaced - by a userspace ABI extension in the future. Do not assume that this - option will be available with compatible effect in future Linux - releases. - - If you are developing software that uses SVE and understand the - implications, you can consider saying Y here. - - If unsure, say N. - -endif - config ARM64_MODULE_CMODEL_LARGE bool diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index da2d602..aa96b4c 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -200,11 +200,6 @@ ENTRY(__cpu_setup) mrs_s x5, ZIDR_EL1 // SVE: Enable full vector len and x5, x5, #ZCR_EL1_LEN_MASK // initially -#ifndef CONFIG_ARM64_SVE_FULL_VECTOR_LENGTH - mov x6, #(512 / 128 - 1) // Clamp VL to 512 bits - cmp x5, x6 - csel x5, x5, x6, lo -#endif msr_s ZCR_EL1, x5 b 2f -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
