From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9AA6CC433E0 for ; Thu, 6 Aug 2020 17:35:18 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 86907206B2 for ; Thu, 6 Aug 2020 17:35:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 86907206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=csgroup.eu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BMwcK6RXSzDqG8 for ; Fri, 7 Aug 2020 03:35:13 +1000 (AEST) 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=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=csgroup.eu Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4BMw9j68H3zDqNR for ; Fri, 7 Aug 2020 03:15:35 +1000 (AEST) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4BMw9Z5jNlz9vCxy; Thu, 6 Aug 2020 19:15:30 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id L3ZlJ7WF5SWB; Thu, 6 Aug 2020 19:15:30 +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 4BMw9Z4r22z9vCql; Thu, 6 Aug 2020 19:15:30 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id CCE768B816; Thu, 6 Aug 2020 19:15:32 +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 qTDg0lNOKxWO; Thu, 6 Aug 2020 19:15:32 +0200 (CEST) Received: from po17688vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 8E68E8B7FC; Thu, 6 Aug 2020 19:15:32 +0200 (CEST) Received: by po17688vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 6271665A68; Thu, 6 Aug 2020 17:15:32 +0000 (UTC) Message-Id: <5748c8f5cf0a9b3686169e2c7709107e6aaec408.1596734105.git.christophe.leroy@csgroup.eu> In-Reply-To: <7baae4086cbb9ffb08c933b065ff7d29dbc03dd6.1596734104.git.christophe.leroy@csgroup.eu> References: <7baae4086cbb9ffb08c933b065ff7d29dbc03dd6.1596734104.git.christophe.leroy@csgroup.eu> From: Christophe Leroy Subject: [PATCH v1 5/5] powerpc/fault: Perform exception fixup in do_page_fault() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , npiggin@gmail.com Date: Thu, 6 Aug 2020 17:15:32 +0000 (UTC) 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Exception fixup doesn't require the heady full regs saving, do it from do_page_fault() directly. For that, split bad_page_fault() in two parts. As bad_page_fault() can also be called from other places than handle_page_fault(), it will still perform exception fixup and fallback on __bad_page_fault(). handle_page_fault() directly calls __bad_page_fault() as the exception fixup will now be done by do_page_fault() Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/entry_32.S | 2 +- arch/powerpc/kernel/exceptions-64e.S | 2 +- arch/powerpc/kernel/exceptions-64s.S | 2 +- arch/powerpc/mm/fault.c | 33 ++++++++++++++++++++-------- 4 files changed, 27 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index f4d0af8e1136..c198786591f9 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -678,7 +678,7 @@ handle_page_fault: mr r5,r3 addi r3,r1,STACK_FRAME_OVERHEAD lwz r4,_DAR(r1) - bl bad_page_fault + bl __bad_page_fault b ret_from_except_full #ifdef CONFIG_PPC_BOOK3S_32 diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index d9ed79415100..dd9161ea5da8 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S @@ -1024,7 +1024,7 @@ storage_fault_common: mr r5,r3 addi r3,r1,STACK_FRAME_OVERHEAD ld r4,_DAR(r1) - bl bad_page_fault + bl __bad_page_fault b ret_from_except /* diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index f7d748b88705..2cb3bcfb896d 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -3254,7 +3254,7 @@ handle_page_fault: mr r5,r3 addi r3,r1,STACK_FRAME_OVERHEAD ld r4,_DAR(r1) - bl bad_page_fault + bl __bad_page_fault b interrupt_return /* We have a data breakpoint exception - handle it */ diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index edde169ba3a6..bd6e397eb84a 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -542,10 +542,20 @@ NOKPROBE_SYMBOL(__do_page_fault); int do_page_fault(struct pt_regs *regs, unsigned long address, unsigned long error_code) { + const struct exception_table_entry *entry; enum ctx_state prev_state = exception_enter(); int rc = __do_page_fault(regs, address, error_code); exception_exit(prev_state); - return rc; + if (likely(!rc)) + return 0; + + entry = search_exception_tables(regs->nip); + if (unlikely(!entry)) + return rc; + + instruction_pointer_set(regs, extable_fixup(entry)); + + return 0; } NOKPROBE_SYMBOL(do_page_fault); @@ -554,17 +564,10 @@ NOKPROBE_SYMBOL(do_page_fault); * It is called from the DSI and ISI handlers in head.S and from some * of the procedures in traps.c. */ -void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) +void __bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) { - const struct exception_table_entry *entry; int is_write = page_fault_is_write(regs->dsisr); - /* Are we prepared to handle this fault? */ - if ((entry = search_exception_tables(regs->nip)) != NULL) { - regs->nip = extable_fixup(entry); - return; - } - /* kernel has accessed a bad area */ switch (TRAP(regs)) { @@ -598,3 +601,15 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) die("Kernel access of bad area", regs, sig); } + +void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) +{ + const struct exception_table_entry *entry; + + /* Are we prepared to handle this fault? */ + entry = search_exception_tables(instruction_pointer(regs)); + if (entry) + instruction_pointer_set(regs, extable_fixup(entry)); + else + __bad_page_fault(regs, address, sig); +} -- 2.25.0