From patchwork Wed Feb 22 16:12:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jiaxun Yang X-Patchwork-Id: 13149328 X-Patchwork-Delegate: bpf@iogearbox.net 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 818F2C6FA99 for ; Wed, 22 Feb 2023 16:12:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232103AbjBVQMi (ORCPT ); Wed, 22 Feb 2023 11:12:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232127AbjBVQMd (ORCPT ); Wed, 22 Feb 2023 11:12:33 -0500 Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5FB33D092; Wed, 22 Feb 2023 08:12:32 -0800 (PST) Received: from compute2.internal (compute2.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id 6123F5C00CD; Wed, 22 Feb 2023 11:12:32 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute2.internal (MEProxy); Wed, 22 Feb 2023 11:12:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=flygoat.com; h= cc:cc:content-transfer-encoding:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:sender :subject:subject:to:to; s=fm2; t=1677082352; x=1677168752; bh=6P LncvDNe/nJ55qRYE4c+4zrSl5PSlFbdt4C/GIEcco=; b=aH62uEIk63UXx1CdBP MrPiynszOEQQKeSVOgh5rzwrdmLksq7nprALqTARhAJH/9s8y/k4b0BmWrRclpCC NSnuqUDJNkKazc5qxkxCbKgymEjhkO0d2oL7kaN9RfwVvh8I1ml00OS6g+6PFvJp GDU+fLCa2xe0fJfsBSrLFTJg3fjEDJApuf6DStjP0ejIBduwKKC0c7JMgVuFC2xP TRqUHBXfH0eDGu6IfYzSvOzpjnLduVEfl7EGf9NdjAQcUssJGhOkOuOjtF2jxnMr lYXbJ94TSbPZ2DQUwItMBNiNyl7wNwplAEPcP2xU1U8V4RoLAHo5yeC6gKP7YuCL JvHQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm1; t=1677082352; x=1677168752; bh=6PLncvDNe/nJ5 5qRYE4c+4zrSl5PSlFbdt4C/GIEcco=; b=ldnB4JNPTsZqfVuigS5UjTIMcrR4l GO5rL+RdG2I/uelk/zPpR+JWaVISGYsq3yzmFOZw5wDYNkMhX8Q8FX1UuDE7Pz+b iYd0WsVeAp19f6UDfv22mS/UL+hVw9Od+OLECQTFKW3z1YyeM8livcxh+ILvl/B8 Y8hbJphQjpi4I5KcIIirX9yXv185tYjOsXZ0L8AzZmgbPIBQVsiX4aE9zFqZp+aD sF4KZweYmyZ41RaayPcyNpxieX7mTWCHuKgQcL+n+qVdzp8qw7zH3QiOaY76aENy kZdeOZoGG/EewPeqKEK1PENt1KqgPxVGg1OTz1ms+rkJ6hk99Ir9fxozw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvhedrudejledgkeegucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefhvfevufffkffojghfggfgsedtke ertdertddtnecuhfhrohhmpeflihgrgihunhcujggrnhhguceojhhirgiguhhnrdihrghn ghesfhhlhihgohgrthdrtghomheqnecuggftrfgrthhtvghrnhepfeeludefheegvdeuvd dvgeekgfdvtdettdelieeihfegtedugeekhfdvhfejfedtnecuvehluhhsthgvrhfuihii vgeptdenucfrrghrrghmpehmrghilhhfrhhomhepjhhirgiguhhnrdihrghnghesfhhlhi hgohgrthdrtghomh X-ME-Proxy: Feedback-ID: ifd894703:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 22 Feb 2023 11:12:30 -0500 (EST) From: Jiaxun Yang To: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org, tsbogend@alpha.franken.de, johan.almbladh@anyfinetworks.com, paulburton@kernel.org, bpf@vger.kernel.org, Jiaxun Yang Subject: [PATCH 2/2] MIPS: ebpf jit: Implement R4000 workarounds Date: Wed, 22 Feb 2023 16:12:22 +0000 Message-Id: <20230222161222.11879-3-jiaxun.yang@flygoat.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) In-Reply-To: <20230222161222.11879-1-jiaxun.yang@flygoat.com> References: <20230222161222.11879-1-jiaxun.yang@flygoat.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net For R4000 erratas around multiplication and division instructions, as our use of those instructions are always followed by mflo/mfhi instructions, the only issue we need care is "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0" Errata 28: "A double-word or a variable shift may give an incorrect result if executed while an integer multiplication is in progress." We just emit a mfhi $0 to ensure the operation is completed after every multiplication instruction accorading to workaround suggestion in the document. Signed-off-by: Jiaxun Yang Reviewed-by: Philippe Mathieu-Daudé Acked-by: Johan Almbladh --- arch/mips/Kconfig | 4 +--- arch/mips/net/bpf_jit_comp32.c | 4 ++++ arch/mips/net/bpf_jit_comp64.c | 3 +++ 3 files changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index df0910e3895c..5ea07c833c5b 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -63,9 +63,7 @@ config MIPS select HAVE_DEBUG_STACKOVERFLOW select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE - select HAVE_EBPF_JIT if !CPU_MICROMIPS && \ - !CPU_R4000_WORKAROUNDS && \ - !CPU_R4400_WORKAROUNDS + select HAVE_EBPF_JIT if !CPU_MICROMIPS select HAVE_EXIT_THREAD select HAVE_FAST_GUP select HAVE_FTRACE_MCOUNT_RECORD diff --git a/arch/mips/net/bpf_jit_comp32.c b/arch/mips/net/bpf_jit_comp32.c index ace5db3fbd17..fee334544d2f 100644 --- a/arch/mips/net/bpf_jit_comp32.c +++ b/arch/mips/net/bpf_jit_comp32.c @@ -446,6 +446,9 @@ static void emit_mul_i64(struct jit_context *ctx, const u8 dst[], s32 imm) } else { emit(ctx, multu, hi(dst), src); emit(ctx, mflo, hi(dst)); + /* Ensure multiplication is completed */ + if (IS_ENABLED(CONFIG_CPU_R4000_WORKAROUNDS)) + emit(ctx, mfhi, MIPS_R_ZERO); } /* hi(dst) = hi(dst) - lo(dst) */ @@ -504,6 +507,7 @@ static void emit_mul_r64(struct jit_context *ctx, } else { emit(ctx, multu, lo(dst), lo(src)); emit(ctx, mflo, lo(dst)); + /* No need for workaround because we have this mfhi */ emit(ctx, mfhi, tmp); } diff --git a/arch/mips/net/bpf_jit_comp64.c b/arch/mips/net/bpf_jit_comp64.c index 0e7c1bdcf914..5f5a93f997bc 100644 --- a/arch/mips/net/bpf_jit_comp64.c +++ b/arch/mips/net/bpf_jit_comp64.c @@ -228,6 +228,9 @@ static void emit_alu_r64(struct jit_context *ctx, u8 dst, u8 src, u8 op) } else { emit(ctx, dmultu, dst, src); emit(ctx, mflo, dst); + /* Ensure multiplication is completed */ + if (IS_ENABLED(CONFIG_CPU_R4000_WORKAROUNDS)) + emit(ctx, mfhi, MIPS_R_ZERO); } break; /* dst = dst / src */