From patchwork Sat May 18 16:04:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shawn Landden X-Patchwork-Id: 1101421 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 455qlK41Mzz9s9y for ; Sun, 19 May 2019 02:06:05 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=git.icu Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 455qlK39S2zDqPg for ; Sun, 19 May 2019 02:06:05 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=git.icu (client-ip=163.172.180.134; helo=git.icu; envelope-from=shawn@git.icu; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=git.icu Received: from git.icu (git.icu [163.172.180.134]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 455qk01vryzDqLg for ; Sun, 19 May 2019 02:04:55 +1000 (AEST) Received: from localhost.localdomain (minicloud.parqtec.unicamp.br [143.106.167.126]) by git.icu (Postfix) with ESMTPSA id C3D2A220850; Sat, 18 May 2019 16:04:47 +0000 (UTC) From: Shawn Landden To: Subject: [RESEND v4 PATCH 1/2] [PowerPC] Add simd.h implementation Date: Sat, 18 May 2019 13:04:40 -0300 Message-Id: <20190518160441.25008-1-shawn@git.icu> X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a In-Reply-To: <20190515013725.2198-1-shawn@git.icu> References: <20190515013725.2198-1-shawn@git.icu> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Mackerras , Shawn Landden , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Based off the x86 one. WireGuard really wants to be able to do SIMD in interrupts, so it can accelerate its in-bound path. v4: allow using the may_use_simd symbol even when it always returns false (via include guards) Signed-off-by: Shawn Landden --- arch/powerpc/include/asm/simd.h | 17 +++++++++++++++++ arch/powerpc/kernel/process.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 47 insertions(+) create mode 100644 arch/powerpc/include/asm/simd.h diff --git a/arch/powerpc/include/asm/simd.h b/arch/powerpc/include/asm/simd.h new file mode 100644 index 000000000..2fe26f258 --- /dev/null +++ b/arch/powerpc/include/asm/simd.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +/* + * may_use_simd - whether it is allowable at this time to issue SIMD + * instructions or access the SIMD register file + * + * It's always ok in process context (ie "not interrupt") + * but it is sometimes ok even from an irq. + */ +#ifdef CONFIG_PPC_FPU +extern bool may_use_simd(void); +#else +static inline bool may_use_simd(void) +{ + return false; +} +#endif diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index dd9e0d538..ef534831f 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -345,6 +345,36 @@ static int restore_altivec(struct task_struct *tsk) } return 0; } + +/* + * Were we in user mode when we were + * interrupted? + * + * Doing kernel_altivec/vsx_begin/end() is ok if we are running + * in an interrupt context from user mode - we'll just + * save the FPU state as required. + */ +static bool interrupted_user_mode(void) +{ + struct pt_regs *regs = get_irq_regs(); + + return regs && user_mode(regs); +} + +/* + * Can we use FPU in kernel mode with the + * whole "kernel_fpu/altivec/vsx_begin/end()" sequence? + * + * It's always ok in process context (ie "not interrupt") + * but it is sometimes ok even from an irq. + */ +bool may_use_simd(void) +{ + return !in_interrupt() || + interrupted_user_mode(); +} +EXPORT_SYMBOL(may_use_simd); + #else #define loadvec(thr) 0 static inline int restore_altivec(struct task_struct *tsk) { return 0; }