From patchwork Sat Nov 28 08:18:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huang Pei X-Patchwork-Id: 1407474 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=8.43.85.97; helo=sourceware.org; envelope-from=libc-alpha-bounces@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=loongson.cn Received: from sourceware.org (unknown [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4Cjktj0YPkz9s1l for ; Sat, 28 Nov 2020 19:19:41 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 5F5BE3851C2F; Sat, 28 Nov 2020 08:19:38 +0000 (GMT) X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by sourceware.org (Postfix) with ESMTP id 7A8803851C2F for ; Sat, 28 Nov 2020 08:19:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 7A8803851C2F Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=huangpei@loongson.cn Received: from localhost.localdomain (unknown [182.149.161.68]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9AxetHVB8Jf7NEXAA--.15226S5; Sat, 28 Nov 2020 16:18:38 +0800 (CST) From: Huang Pei To: Joseph Myers Subject: [PATCH 3/3] mips: remove register spill Date: Sat, 28 Nov 2020 16:18:17 +0800 Message-Id: <20201128081817.15463-4-huangpei@loongson.cn> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201128081817.15463-1-huangpei@loongson.cn> References: <20201128081817.15463-1-huangpei@loongson.cn> X-CM-TRANSID: AQAAf9AxetHVB8Jf7NEXAA--.15226S5 X-Coremail-Antispam: 1UD129KBjvJXoW7Ar4fWw4rAr43tryUKF48JFb_yoW8WF17pr 1fu3WUGrWrJryrCrnxur1UG3Z5Jwn2yr15Zr9I9F4YkrW5ur1rK39IvFyfGFy3tryfGF48 ZF1vgrn0grW5Za7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBv14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1l84 ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AKxVW8Jr0_Cr1U M2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjx v20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1l F7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkIecxEwVAFwVW8ZwCF04 k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18 MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr4 1lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1l IxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4 A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUFXdbUUUUU= X-CM-SenderInfo: xkxd0whshlqz5rrqw2lrqou0/ X-Spam-Status: No, score=-11.4 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Huacai Chen , Chenghua Xu , libc-alpha Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Before Linux/MIPS 2.6.36, kernel expected setting syscall number(aka "li v0, #sys_number") right precedes "syscall", so the kernel syscall restart sequence can use CP0 EPC - 4 to restart the syscall, because kernel DID NOT save v0 during syscall handling. Linux 2.6.36 canceled this restriction. See sysdeps/unix/sysv/linux/mips/{mips32/sysdep.h,mips64/sysdep.h,sysdep.h} Since glibc-2.24 the minimum kernel version is 3.2(much higer than 2.6.36), I think it is OK to remove the ugly register spill in syscall.S just because of the old convention Signed-off-by: Huang Pei --- sysdeps/unix/sysv/linux/mips/mips64/syscall.S | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) diff --git a/sysdeps/unix/sysv/linux/mips/mips64/syscall.S b/sysdeps/unix/sysv/linux/mips/mips64/syscall.S index aab1f389aa..089524a40b 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/syscall.S +++ b/sysdeps/unix/sysv/linux/mips/mips64/syscall.S @@ -27,14 +27,9 @@ .text NESTED (syscall, SZREG, ra) - .mask 0x00010000, -2 * SZREG + .mask 0x00000000, 0 .fmask 0x00000000, 0 - PTR_ADDIU sp, -2 * SZREG - cfi_adjust_cfa_offset (2 * SZREG) - REG_S s0, (sp) - cfi_rel_offset (s0, 0) - - move s0, a0 + move v0, a0 move a0, a1 /* shift arg1 - arg7. */ move a1, a2 move a2, a3 @@ -43,13 +38,8 @@ NESTED (syscall, SZREG, ra) move a5, a6 move a6, a7 - move v0, s0 /* Syscall number -> v0 */ syscall /* Do the system call. */ - REG_L s0, (sp) - cfi_restore (s0) - PTR_ADDIU sp, 2 * SZREG - cfi_adjust_cfa_offset (-2 * 2 * SZREG) bne a3, zero, L(error) ret