From patchwork Tue Jul 2 13:51:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1955346 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=patchwork.ozlabs.org) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4WD4JN3WRNz1xqb for ; Tue, 2 Jul 2024 23:58:44 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4WD4JN027fz7BDS for ; Tue, 2 Jul 2024 23:58:44 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=csgroup.eu (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=lists.ozlabs.org) Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4WD49l1F6Fz3g5L for ; Tue, 2 Jul 2024 23:52:58 +1000 (AEST) Received: from localhost (mailhub3.si.c-s.fr [192.168.12.233]) by localhost (Postfix) with ESMTP id 4WD48L4787z9v3s; Tue, 2 Jul 2024 15:51:46 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tD71Vn51syID; Tue, 2 Jul 2024 15:51:46 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4WD4865kqdz9v7N; Tue, 2 Jul 2024 15:51:34 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C0D818B774; Tue, 2 Jul 2024 15:51:34 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id pWxGaw-G7BNY; Tue, 2 Jul 2024 15:51:34 +0200 (CEST) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.233.12]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4D51F8B764; Tue, 2 Jul 2024 15:51:34 +0200 (CEST) From: Christophe Leroy To: Andrew Morton , Jason Gunthorpe , Peter Xu , Oscar Salvador , Michael Ellerman , Nicholas Piggin Subject: [PATCH v7 18/23] powerpc/e500: Don't pre-check write access on data TLB error Date: Tue, 2 Jul 2024 15:51:30 +0200 Message-ID: <8525518e1657d6032b7e980c1888102828d66950.1719928057.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.44.0 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1719928275; l=1564; i=christophe.leroy@csgroup.eu; s=20211009; h=from:subject:message-id; bh=lXkJFaNOZfYs39NvzB2t7aMNQd5E4EiqpUUgx2rbgYk=; b=UfaTLsrzSij3pYXiv+ejHeSoRAerQa7OpK+kFzmvGET2VlKw+SFhPJdwxpiVLp8BycMHe75De Wk++EkSYFizC/zAfHU9AfP7o7tpmfuohonnxIu+luqjMTdYqXgBexcN X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= 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: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Christophe Leroy Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Don't pre-check write access on read-only pages on data TLB error. Load the TLB anyway and take a DSI exception when it happens. This avoids reading SPRN_ESR at every data TLB error exception. Signed-off-by: Christophe Leroy --- v5: New --- arch/powerpc/kernel/head_85xx.S | 15 --------------- 1 file changed, 15 deletions(-) diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S index a305244afc9f..282e49c51deb 100644 --- a/arch/powerpc/kernel/head_85xx.S +++ b/arch/powerpc/kernel/head_85xx.S @@ -472,27 +472,12 @@ END_BTB_FLUSH_SECTION #endif 4: - /* Mask of required permission bits. Note that while we - * do copy ESR:ST to _PAGE_WRITE position as trying to write - * to an RO page is pretty common, we don't do it with - * _PAGE_DIRTY. We could do it, but it's a fairly rare - * event so I'd rather take the overhead when it happens - * rather than adding an instruction here. We should measure - * whether the whole thing is worth it in the first place - * as we could avoid loading SPRN_ESR completely in the first - * place... - * - * TODO: Is it worth doing that mfspr & rlwimi in the first - * place or can we save a couple of instructions here ? - */ - mfspr r12,SPRN_ESR #ifdef CONFIG_PTE_64BIT li r13,_PAGE_PRESENT|_PAGE_BAP_SR oris r13,r13,_PAGE_ACCESSED@h #else li r13,_PAGE_PRESENT|_PAGE_READ|_PAGE_ACCESSED #endif - rlwimi r13,r12,11,29,29 FIND_PTE andc. r13,r13,r11 /* Check permission */