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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 E1938C433DB for ; Mon, 8 Feb 2021 16:38:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A64C264E8F for ; Mon, 8 Feb 2021 16:38:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233382AbhBHQih (ORCPT ); Mon, 8 Feb 2021 11:38:37 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:28077 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233264AbhBHPOB (ORCPT ); Mon, 8 Feb 2021 10:14:01 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DZ8bW244fzB09ZJ; Mon, 8 Feb 2021 16:10:31 +0100 (CET) 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 g9JU2CYNyksr; Mon, 8 Feb 2021 16:10:31 +0100 (CET) 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 4DZ8bW1KDfzB09ZC; Mon, 8 Feb 2021 16:10:31 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 842F08B7B3; Mon, 8 Feb 2021 16:10:36 +0100 (CET) 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 tZ8nhZkrdozL; Mon, 8 Feb 2021 16:10:36 +0100 (CET) Received: from po16121vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.103]) by messagerie.si.c-s.fr (Postfix) with ESMTP id F1E698B7B2; Mon, 8 Feb 2021 16:10:35 +0100 (CET) Received: by po16121vm.idsi0.si.c-s.fr (Postfix, from userid 0) id E2A386733E; Mon, 8 Feb 2021 15:10:35 +0000 (UTC) Message-Id: <981edfd50d4c980634b74c4bb76b765c499a87ec.1612796617.git.christophe.leroy@csgroup.eu> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v5 16/22] powerpc/syscall: Avoid stack frame in likely part of system_call_exception() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , npiggin@gmail.com, msuchanek@suse.de Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Mon, 8 Feb 2021 15:10:35 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When r3 is not modified, reload it from regs->orig_r3 to free volatile registers. This avoids a stack frame for the likely part of system_call_exception() Before the patch: c000b4d4 : c000b4d4: 7c 08 02 a6 mflr r0 c000b4d8: 94 21 ff e0 stwu r1,-32(r1) c000b4dc: 93 e1 00 1c stw r31,28(r1) c000b4e0: 90 01 00 24 stw r0,36(r1) c000b4e4: 90 6a 00 88 stw r3,136(r10) c000b4e8: 81 6a 00 84 lwz r11,132(r10) c000b4ec: 69 6b 00 02 xori r11,r11,2 c000b4f0: 55 6b ff fe rlwinm r11,r11,31,31,31 c000b4f4: 0f 0b 00 00 twnei r11,0 c000b4f8: 81 6a 00 a0 lwz r11,160(r10) c000b4fc: 55 6b 07 fe clrlwi r11,r11,31 c000b500: 0f 0b 00 00 twnei r11,0 c000b504: 7c 0c 42 e6 mftb r0 c000b508: 83 e2 00 08 lwz r31,8(r2) c000b50c: 81 82 00 28 lwz r12,40(r2) c000b510: 90 02 00 24 stw r0,36(r2) c000b514: 7d 8c f8 50 subf r12,r12,r31 c000b518: 7c 0c 02 14 add r0,r12,r0 c000b51c: 90 02 00 08 stw r0,8(r2) c000b520: 7c 10 13 a6 mtspr 80,r0 c000b524: 81 62 00 70 lwz r11,112(r2) c000b528: 71 60 86 91 andi. r0,r11,34449 c000b52c: 40 82 00 34 bne c000b560 c000b530: 2b 89 01 b6 cmplwi cr7,r9,438 c000b534: 41 9d 00 64 bgt cr7,c000b598 c000b538: 3d 40 c0 5c lis r10,-16292 c000b53c: 55 29 10 3a rlwinm r9,r9,2,0,29 c000b540: 39 4a 41 e8 addi r10,r10,16872 c000b544: 80 01 00 24 lwz r0,36(r1) c000b548: 7d 2a 48 2e lwzx r9,r10,r9 c000b54c: 7c 08 03 a6 mtlr r0 c000b550: 7d 29 03 a6 mtctr r9 c000b554: 83 e1 00 1c lwz r31,28(r1) c000b558: 38 21 00 20 addi r1,r1,32 c000b55c: 4e 80 04 20 bctr After the patch: c000b4d4 : c000b4d4: 81 6a 00 84 lwz r11,132(r10) c000b4d8: 90 6a 00 88 stw r3,136(r10) c000b4dc: 69 6b 00 02 xori r11,r11,2 c000b4e0: 55 6b ff fe rlwinm r11,r11,31,31,31 c000b4e4: 0f 0b 00 00 twnei r11,0 c000b4e8: 80 6a 00 a0 lwz r3,160(r10) c000b4ec: 54 63 07 fe clrlwi r3,r3,31 c000b4f0: 0f 03 00 00 twnei r3,0 c000b4f4: 7d 6c 42 e6 mftb r11 c000b4f8: 81 82 00 08 lwz r12,8(r2) c000b4fc: 80 02 00 28 lwz r0,40(r2) c000b500: 91 62 00 24 stw r11,36(r2) c000b504: 7c 00 60 50 subf r0,r0,r12 c000b508: 7d 60 5a 14 add r11,r0,r11 c000b50c: 91 62 00 08 stw r11,8(r2) c000b510: 7c 10 13 a6 mtspr 80,r0 c000b514: 80 62 00 70 lwz r3,112(r2) c000b518: 70 6b 86 91 andi. r11,r3,34449 c000b51c: 40 82 00 28 bne c000b544 c000b520: 2b 89 01 b6 cmplwi cr7,r9,438 c000b524: 41 9d 00 84 bgt cr7,c000b5a8 c000b528: 80 6a 00 88 lwz r3,136(r10) c000b52c: 3d 40 c0 5c lis r10,-16292 c000b530: 55 29 10 3a rlwinm r9,r9,2,0,29 c000b534: 39 4a 41 e4 addi r10,r10,16868 c000b538: 7d 2a 48 2e lwzx r9,r10,r9 c000b53c: 7d 29 03 a6 mtctr r9 c000b540: 4e 80 04 20 bctr Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/interrupt.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index 107ec39f05cb..205902052112 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -117,6 +117,9 @@ notrace long system_call_exception(long r3, long r4, long r5, return regs->gpr[3]; } return -ENOSYS; + } else { + /* Restore r3 from orig_gpr3 to free up a volatile reg */ + r3 = regs->orig_gpr3; } /* May be faster to do array_index_nospec? */ -- 2.25.0 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 87C95C433E0 for ; Mon, 8 Feb 2021 15:48:05 +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 9FDE664DAF for ; Mon, 8 Feb 2021 15:48:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9FDE664DAF 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 4DZ9Qp4qrPzDvWZ for ; Tue, 9 Feb 2021 02:48:02 +1100 (AEDT) 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=) 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 4DZ8bg4sqNzDr2l for ; Tue, 9 Feb 2021 02:10:39 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DZ8bW244fzB09ZJ; Mon, 8 Feb 2021 16:10:31 +0100 (CET) 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 g9JU2CYNyksr; Mon, 8 Feb 2021 16:10:31 +0100 (CET) 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 4DZ8bW1KDfzB09ZC; Mon, 8 Feb 2021 16:10:31 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 842F08B7B3; Mon, 8 Feb 2021 16:10:36 +0100 (CET) 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 tZ8nhZkrdozL; Mon, 8 Feb 2021 16:10:36 +0100 (CET) Received: from po16121vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.103]) by messagerie.si.c-s.fr (Postfix) with ESMTP id F1E698B7B2; Mon, 8 Feb 2021 16:10:35 +0100 (CET) Received: by po16121vm.idsi0.si.c-s.fr (Postfix, from userid 0) id E2A386733E; Mon, 8 Feb 2021 15:10:35 +0000 (UTC) Message-Id: <981edfd50d4c980634b74c4bb76b765c499a87ec.1612796617.git.christophe.leroy@csgroup.eu> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v5 16/22] powerpc/syscall: Avoid stack frame in likely part of system_call_exception() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , npiggin@gmail.com, msuchanek@suse.de Date: Mon, 8 Feb 2021 15:10:35 +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" When r3 is not modified, reload it from regs->orig_r3 to free volatile registers. This avoids a stack frame for the likely part of system_call_exception() Before the patch: c000b4d4 : c000b4d4: 7c 08 02 a6 mflr r0 c000b4d8: 94 21 ff e0 stwu r1,-32(r1) c000b4dc: 93 e1 00 1c stw r31,28(r1) c000b4e0: 90 01 00 24 stw r0,36(r1) c000b4e4: 90 6a 00 88 stw r3,136(r10) c000b4e8: 81 6a 00 84 lwz r11,132(r10) c000b4ec: 69 6b 00 02 xori r11,r11,2 c000b4f0: 55 6b ff fe rlwinm r11,r11,31,31,31 c000b4f4: 0f 0b 00 00 twnei r11,0 c000b4f8: 81 6a 00 a0 lwz r11,160(r10) c000b4fc: 55 6b 07 fe clrlwi r11,r11,31 c000b500: 0f 0b 00 00 twnei r11,0 c000b504: 7c 0c 42 e6 mftb r0 c000b508: 83 e2 00 08 lwz r31,8(r2) c000b50c: 81 82 00 28 lwz r12,40(r2) c000b510: 90 02 00 24 stw r0,36(r2) c000b514: 7d 8c f8 50 subf r12,r12,r31 c000b518: 7c 0c 02 14 add r0,r12,r0 c000b51c: 90 02 00 08 stw r0,8(r2) c000b520: 7c 10 13 a6 mtspr 80,r0 c000b524: 81 62 00 70 lwz r11,112(r2) c000b528: 71 60 86 91 andi. r0,r11,34449 c000b52c: 40 82 00 34 bne c000b560 c000b530: 2b 89 01 b6 cmplwi cr7,r9,438 c000b534: 41 9d 00 64 bgt cr7,c000b598 c000b538: 3d 40 c0 5c lis r10,-16292 c000b53c: 55 29 10 3a rlwinm r9,r9,2,0,29 c000b540: 39 4a 41 e8 addi r10,r10,16872 c000b544: 80 01 00 24 lwz r0,36(r1) c000b548: 7d 2a 48 2e lwzx r9,r10,r9 c000b54c: 7c 08 03 a6 mtlr r0 c000b550: 7d 29 03 a6 mtctr r9 c000b554: 83 e1 00 1c lwz r31,28(r1) c000b558: 38 21 00 20 addi r1,r1,32 c000b55c: 4e 80 04 20 bctr After the patch: c000b4d4 : c000b4d4: 81 6a 00 84 lwz r11,132(r10) c000b4d8: 90 6a 00 88 stw r3,136(r10) c000b4dc: 69 6b 00 02 xori r11,r11,2 c000b4e0: 55 6b ff fe rlwinm r11,r11,31,31,31 c000b4e4: 0f 0b 00 00 twnei r11,0 c000b4e8: 80 6a 00 a0 lwz r3,160(r10) c000b4ec: 54 63 07 fe clrlwi r3,r3,31 c000b4f0: 0f 03 00 00 twnei r3,0 c000b4f4: 7d 6c 42 e6 mftb r11 c000b4f8: 81 82 00 08 lwz r12,8(r2) c000b4fc: 80 02 00 28 lwz r0,40(r2) c000b500: 91 62 00 24 stw r11,36(r2) c000b504: 7c 00 60 50 subf r0,r0,r12 c000b508: 7d 60 5a 14 add r11,r0,r11 c000b50c: 91 62 00 08 stw r11,8(r2) c000b510: 7c 10 13 a6 mtspr 80,r0 c000b514: 80 62 00 70 lwz r3,112(r2) c000b518: 70 6b 86 91 andi. r11,r3,34449 c000b51c: 40 82 00 28 bne c000b544 c000b520: 2b 89 01 b6 cmplwi cr7,r9,438 c000b524: 41 9d 00 84 bgt cr7,c000b5a8 c000b528: 80 6a 00 88 lwz r3,136(r10) c000b52c: 3d 40 c0 5c lis r10,-16292 c000b530: 55 29 10 3a rlwinm r9,r9,2,0,29 c000b534: 39 4a 41 e4 addi r10,r10,16868 c000b538: 7d 2a 48 2e lwzx r9,r10,r9 c000b53c: 7d 29 03 a6 mtctr r9 c000b540: 4e 80 04 20 bctr Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/interrupt.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index 107ec39f05cb..205902052112 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -117,6 +117,9 @@ notrace long system_call_exception(long r3, long r4, long r5, return regs->gpr[3]; } return -ENOSYS; + } else { + /* Restore r3 from orig_gpr3 to free up a volatile reg */ + r3 = regs->orig_gpr3; } /* May be faster to do array_index_nospec? */ -- 2.25.0