From patchwork Wed Oct 27 18:44:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 12587821 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 6DCCAC433EF for ; Wed, 27 Oct 2021 18:51:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FA126103C for ; Wed, 27 Oct 2021 18:51:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243586AbhJ0SyN (ORCPT ); Wed, 27 Oct 2021 14:54:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:33640 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240445AbhJ0SyM (ORCPT ); Wed, 27 Oct 2021 14:54:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B022B610C8; Wed, 27 Oct 2021 18:51:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635360707; bh=xZLlC1q99EwXMUJBADXxGM/i8bzqpIz0Zg3di6U+rpQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cMepY/3c0JzMcbeP41jh6q4egO8SQLxGVG6xpbWmN+FbQ7VtcL5wZzUfRwVfCl6PD g+DatSWOvczkjN0B+ENCYu5GYFm8FfPfx+WknKorfkWfT7ortm7wUyXAkrCjK8ZuMo QMDWRybm/MU7deFe+jBZJpYlVwtyImIzCAL0+fktti855NtsenghOgOfEVoKcw51NG SSF14dWftEGrmRwC8wPeuowUT7khxhONeNaRn+Ha4VF1KEUklSyNnlXsRyiIxy/K6t O0MNyBFuZo530WgadPWE3ku6ADnZIIEexxYNb5gJoJ7wzmgNjBgb/4h8rDTX/oLMtv yJC+zbFqgcH0g== 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 v5 19/38] arm64/sme: Implement SVCR context switching Date: Wed, 27 Oct 2021 19:44:05 +0100 Message-Id: <20211027184424.166237-20-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211027184424.166237-1-broonie@kernel.org> References: <20211027184424.166237-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3708; h=from:subject; bh=xZLlC1q99EwXMUJBADXxGM/i8bzqpIz0Zg3di6U+rpQ=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBheZ31Idi3hrnKS94NlwPXznM5UHTI5wVCixiKNwI4 VgRe1RWJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYXmd9QAKCRAk1otyXVSH0D65B/ wO4hqCBSjlhn9Q+xbfN6dMiAlz+UAqxUr119QWrKnQEqGmGoLSR+Xz49J5uw7WfTsAvwJcGBrqw6JA bFdFRKOC6/Vh6UJgAN1SHO/k1+QEIH9Wce7/WJQ2R4Ev8A7XmjNexdzjLy10zlz7cqI888vzOBU0Ur vbfPArlcHaY5bcQUaLpDFrcDkfpGILdrcG+dOM1lepPARuE/mZqqAqS1KJGrBdLst0S5omj+DjV7V4 nqQpkdE0SAVpuWKskSJbzeh4fU1ckg7hJ66Rwpge92lyKYBFE5YqJqlhXzhTvV2bjzRwMHTVQrSXXY PTLfDEMy31ncfSGOdNmFr2DxD4JCEy 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 0af82c518979..d6e6bec6b490 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)) { @@ -731,6 +738,10 @@ 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);