From patchwork Mon Oct 18 19:08:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 12567791 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22A39C433F5 for ; Mon, 18 Oct 2021 19:11:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B7736128B for ; Mon, 18 Oct 2021 19:11:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232759AbhJRTNX (ORCPT ); Mon, 18 Oct 2021 15:13:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:38510 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231890AbhJRTNW (ORCPT ); Mon, 18 Oct 2021 15:13:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A4CCE60ED3; Mon, 18 Oct 2021 19:11:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634584271; bh=MsTED/mKGInbKff7tMbBmrASFeZ5+Ym+qIYJfb6ihGM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rxlXNa3UBFL/eh2PsjfkwyRrGr0s181t/iAgOac41w7ftjoWfjp7PbHzebIW4KQdo nqST0sM9kGlKgqGjqFr4Dn+KWSyLb7l6cBMwBExMZk6gxIH0u3/9lOQq53tA9w3Ont Pr0Ebi//Q+ulCozIjOuzRQYfz3aVzzLzniEl7A/Wnu6i/dRCIurM/NSeS0bS4TFRVP svNwN8zUGqLcaAuya3Yd7un/4kEQ6PCfPXUGN9O6FhnVUgpJR9Sydt/KDtQt+LNLne UMPZX25FVoisszESVNE/Wovtwbhw8DGi+i9j4XkqjEnV1eRoY4Tkrgo0HOIEkKto6d pHvVGfemOrpWA== From: Mark Brown To: Catalin Marinas , Will Deacon , Shuah Khan , Shuah Khan Cc: Alan Hayward , Luis Machado , Salil Akerkar , Basant Kumar Dwivedi , Szabolcs Nagy , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, Mark Brown Subject: [PATCH v2 24/42] arm64/sme: Implement SVCR context switching Date: Mon, 18 Oct 2021 20:08:40 +0100 Message-Id: <20211018190858.2119209-25-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211018190858.2119209-1-broonie@kernel.org> References: <20211018190858.2119209-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3708; h=from:subject; bh=MsTED/mKGInbKff7tMbBmrASFeZ5+Ym+qIYJfb6ihGM=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBhbcY6MFf7qQRz+Zh0BYQYI6GeroeSFuZtmbcSyqvA a8KIYw6JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYW3GOgAKCRAk1otyXVSH0LffB/ 4kMQKh2xa47bT/yED0KityGQ8dxqEzugq31d9Foq5+WOJgjdgFUSUerBnIVZdJptSMN61cf5vPf4+Q yaAvAN9PHDUTdiXclcoCdEZLPpBeEnZKtnVE5GxevDUaz+L/IPuVU0gp/MM4TfNLnhbO9mLNvxYaLc Gmlu1GrtCEk+jGasbaIzCc9Q/8N5+MY805EsQA9l2lt4UOICB+JU5IJytuHXy230VjiE2bDbTQmPAL w+LEscX/VErHDoOSXC42HynuGfCNTYVsIDwF0nMJt6QXjDgjfvvoD0/a3ZlPHLVq4+oot+qZMJ9mTT C+WVhRraehHePbvt0QZnkmYU3ZoAzC X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org In SME the use of both streaming SVE mode and ZA are tracked through PSTATE.SM and PSTATE.ZA, visible through the system register SVCR. In order to context switch the floating point state for SME we need to context switch the contents of this register as part of context switching the floating point state. Since changing the vector length exits streaming SVE mode and disables ZA we also make sure we update SVCR appropriately when setting vector length, and similarly ensure that new threads have streaming SVE mode and ZA disabled. Signed-off-by: Mark Brown --- arch/arm64/include/asm/processor.h | 1 + arch/arm64/include/asm/thread_info.h | 1 + arch/arm64/kernel/fpsimd.c | 11 +++++++++++ arch/arm64/kernel/process.c | 2 ++ 4 files changed, 15 insertions(+) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 51eca2513cb5..3c235e165725 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -168,6 +168,7 @@ struct thread_struct { u64 mte_ctrl; #endif u64 sctlr_user; + u64 svcr; u64 tpidr2_el0; }; diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 5c4355204f4a..03cb88f63317 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -81,6 +81,7 @@ int arch_dup_task_struct(struct task_struct *dst, #define TIF_SVE_VL_INHERIT 24 /* Inherit SVE vl_onexec across exec */ #define TIF_SSBD 25 /* Wants SSB mitigation */ #define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */ +#define TIF_SME 27 /* SME in use */ #define TIF_SME_VL_INHERIT 28 /* Inherit SME vl_onexec across exec */ #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index a619ce38eddc..c43bf252482f 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -355,6 +355,9 @@ static void task_fpsimd_load(void) WARN_ON(!system_supports_fpsimd()); WARN_ON(!have_cpu_fpsimd_context()); + if (IS_ENABLED(CONFIG_ARM64_SME) && test_thread_flag(TIF_SME)) + write_sysreg_s(current->thread.svcr, SYS_SVCR_EL0); + if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) { sve_set_vq(sve_vq_from_vl(task_get_sve_vl(current)) - 1); sve_load_state(sve_pffr(¤t->thread), @@ -380,6 +383,10 @@ static void fpsimd_save(void) if (test_thread_flag(TIF_FOREIGN_FPSTATE)) return; + if (IS_ENABLED(CONFIG_ARM64_SME) && + test_thread_flag(TIF_SME)) + current->thread.svcr = read_sysreg_s(SYS_SVCR_EL0); + if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) { if (WARN_ON(sve_get_vl() != last->sve_vl)) { @@ -734,6 +741,10 @@ int vec_set_vector_length(struct task_struct *task, enum vec_type type, if (test_and_clear_tsk_thread_flag(task, TIF_SVE)) sve_to_fpsimd(task); + if (system_supports_sme() && type == ARM64_VEC_SME) + task->thread.svcr &= ~(SYS_SVCR_EL0_SM_MASK | + SYS_SVCR_EL0_ZA_MASK); + if (task == current) put_cpu_fpsimd_context(); diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 3f4279ad68bc..4dd35619ece6 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -309,6 +309,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) dst->thread.sve_state = NULL; clear_tsk_thread_flag(dst, TIF_SVE); + dst->thread.svcr = 0; + /* clear any pending asynchronous tag fault raised by the parent */ clear_tsk_thread_flag(dst, TIF_MTE_ASYNC_FAULT);