From patchwork Thu May 19 13:59:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 12855125 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A047BC433EF for ; Thu, 19 May 2022 14:07:37 +0000 (UTC) Received: from localhost ([::1]:49232 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nrgoS-0003bY-P0 for qemu-devel@archiver.kernel.org; Thu, 19 May 2022 10:07:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41110) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nrgga-0002Bp-GY; Thu, 19 May 2022 09:59:28 -0400 Received: from mail-pj1-x1031.google.com ([2607:f8b0:4864:20::1031]:40921) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nrggV-0001Yw-PU; Thu, 19 May 2022 09:59:28 -0400 Received: by mail-pj1-x1031.google.com with SMTP id nr2-20020a17090b240200b001df2b1bfc40so8863756pjb.5; Thu, 19 May 2022 06:59:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Wbk3Tw473kMoNfK7VGBxPHBOaju8kfs9PwAcUJMVe7Q=; b=YYhyBW9Jd1pG5irwXYTRgNx72WGUUUe+CtPZO9Fz+2g+g2TikIQ3z/ITgvrlYtcuar m15iGHs4lMEtJqUznNJAn6z/lL/CtNs1hSlLZlgVwq4/N/RvT+CID8ozzYv94/yZy6H2 3ws1B8AUEs//f7gACMS1X3obqhypyBVlmV0RdRUy/kEv+b8pBc8yi8nLh6y7kxSqAZyl 3o+hBcblocKEDa1ZdsanborFEzbTGKYE9VlqN44g31YABmU4iM/G3tft8KXnCLb3ZDPt aHPQ1hOqYAaYUthkFRMFCYFHHj+aa81w/v0Y0weflChiWz1l7obN+hvSoJmw9/6OdrmX Y7PQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Wbk3Tw473kMoNfK7VGBxPHBOaju8kfs9PwAcUJMVe7Q=; b=3aXJt6oF5CudvAsXac76A0Yl/l25earjwlWUutvHZn5UMgiIPEHNKrBWCSZ+c/3avy bFqdJMpl9U++1fj3x+p+rmNVC9VXcmyLZDhHT4o0UFa/7KrDYRf1dE2r3Ir3uen1UAXJ 2QZeQD/CbGUQJYOCbRBhwWBek3JRgecRGMr7+Si0xsVJn76fxq02HG4npTxyaxpJghkP TGniOfZqtJ9J4tDiO0RFMpzgJwPw2N0RWGNkefweqSsXv/7sZJlZ6cpc+zkz/2sqSH2t 5yaV3oWKIp6jpWcxz9F6BbtQmo5R5EODtTK6PcZI6eHUzkwiQRNZqNUhvKeUOewdVdav bf0A== X-Gm-Message-State: AOAM5323GX8MB8OAfGsqlF1yGJrZA6G3m0MVWJBToYNc2nD8FXSAb3oP XMVWyUyq7wLCLYzSxKbviR4T4ohUrEy1uw== X-Google-Smtp-Source: ABdhPJyrvZ54UvMr527Zo7DSwwxwQ3N/U0/q6j5EK8PVaLoHV2Xo3f7F6f4Q6wNOz/KJdYeohU01Vw== X-Received: by 2002:a17:90a:d505:b0:1df:7d0e:a03c with SMTP id t5-20020a17090ad50500b001df7d0ea03cmr6095287pju.170.1652968761850; Thu, 19 May 2022 06:59:21 -0700 (PDT) Received: from bobo.ibm.com ([118.208.131.68]) by smtp.gmail.com with ESMTPSA id l8-20020a17090b078800b001d9927ef1desm5603817pjz.34.2022.05.19.06.59.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 May 2022 06:59:21 -0700 (PDT) From: Nicholas Piggin To: qemu-ppc@nongnu.org Cc: Nicholas Piggin , qemu-devel@nongnu.org, Richard Henderson Subject: [PATCH 1/4] target/ppc: Fix eieio memory ordering semantics Date: Thu, 19 May 2022 23:59:05 +1000 Message-Id: <20220519135908.21282-2-npiggin@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220519135908.21282-1-npiggin@gmail.com> References: <20220519135908.21282-1-npiggin@gmail.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::1031; envelope-from=npiggin@gmail.com; helo=mail-pj1-x1031.google.com X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The generated eieio memory ordering semantics do not match the instruction definition in the architecture. Add a big comment to explain this strange instruction and correct the memory ordering behaviour. Signed-off: Nicholas Piggin Reviewed-by: Richard Henderson --- target/ppc/translate.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/target/ppc/translate.c b/target/ppc/translate.c index fa34f81c30..eb42f7e459 100644 --- a/target/ppc/translate.c +++ b/target/ppc/translate.c @@ -3513,7 +3513,32 @@ static void gen_stswx(DisasContext *ctx) /* eieio */ static void gen_eieio(DisasContext *ctx) { - TCGBar bar = TCG_MO_LD_ST; + TCGBar bar = TCG_MO_ALL; + + /* + * eieio has complex semanitcs. It provides memory ordering between + * operations in the set: + * - loads from CI memory. + * - stores to CI memory. + * - stores to WT memory. + * + * It separately also orders memory for operations in the set: + * - stores to cacheble memory. + * + * It also serializes instructions: + * - dcbt and dcbst. + * + * It separately serializes: + * - tlbie and tlbsync. + * + * And separately serializes: + * - slbieg, slbiag, and slbsync. + * + * The end result is that CI memory ordering requires TCG_MO_ALL + * and it is not possible to special-case more relaxed ordering for + * cacheable accesses. TCG_BAR_SC is required to provide this + * serialization. + */ /* * POWER9 has a eieio instruction variant using bit 6 as a hint to