From patchwork Mon Nov 1 09:51:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: gaosong X-Patchwork-Id: 12596255 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8185AC433EF for ; Mon, 1 Nov 2021 10:06:33 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 23469610CA for ; Mon, 1 Nov 2021 10:06:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 23469610CA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:53474 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mhUCy-0003Or-QQ for qemu-devel@archiver.kernel.org; Mon, 01 Nov 2021 06:06:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54304) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mhTzn-0005wK-AC for qemu-devel@nongnu.org; Mon, 01 Nov 2021 05:52:51 -0400 Received: from mail.loongson.cn ([114.242.206.163]:51054 helo=loongson.cn) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mhTzl-0008EQ-2u for qemu-devel@nongnu.org; Mon, 01 Nov 2021 05:52:51 -0400 Received: from kvm-dev1.localdomain (unknown [10.2.5.134]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dxn2u3uH9hbKIjAA--.55994S31; Mon, 01 Nov 2021 17:52:33 +0800 (CST) From: Song Gao To: qemu-devel@nongnu.org Subject: [PATCH v8 29/29] linux-user: Add safe syscall handling for loongarch64 hosts Date: Mon, 1 Nov 2021 17:51:51 +0800 Message-Id: <1635760311-20015-30-git-send-email-gaosong@loongson.cn> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1635760311-20015-1-git-send-email-gaosong@loongson.cn> References: <1635760311-20015-1-git-send-email-gaosong@loongson.cn> X-CM-TRANSID: AQAAf9Dxn2u3uH9hbKIjAA--.55994S31 X-Coremail-Antispam: 1UD129KBjvJXoWxWr13CrWUGw13CFy3CFW3ZFb_yoWrCFWrpa s3Cw15Kr48GFn7Cr9rXw4UKFyfZr4fJF1Ykr4SvFZYyrZrJr9Yqr1qga4vyF13CrnFkFWj vF40y398uF4DWaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnUUvcSsGvfC2KfnxnUUI43ZEXa7xR_UUUUUUUUU== X-CM-SenderInfo: 5jdr20tqj6z05rqj20fqof0/ Received-SPF: pass client-ip=114.242.206.163; envelope-from=gaosong@loongson.cn; helo=loongson.cn X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham 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: , Cc: peter.maydell@linaro.org, thuth@redhat.com, chenhuacai@loongson.cn, philmd@redhat.com, i.qemu@xen0n.name, richard.henderson@linaro.org, laurent@vivier.eu, peterx@redhat.com, f4bug@amsat.org, yangxiaojuan@loongson.cn, alistair.francis@wdc.com, maobibo@loongson.cn, pbonzini@redhat.com, bmeng.cn@gmail.com, alex.bennee@linaro.org, gaosong@loongson.cn Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Base-on: <20210925173032.2434906-29-git@xen0n.name> Signed-off-by: Song Gao Signed-off-by: Xiaojuan Yang --- linux-user/host/loongarch64/hostdep.h | 23 ++++++++ linux-user/host/loongarch64/safe-syscall.inc.S | 80 ++++++++++++++++++++++++++ 2 files changed, 103 insertions(+) create mode 100644 linux-user/host/loongarch64/safe-syscall.inc.S diff --git a/linux-user/host/loongarch64/hostdep.h b/linux-user/host/loongarch64/hostdep.h index 4e55695..e3d5fa7 100644 --- a/linux-user/host/loongarch64/hostdep.h +++ b/linux-user/host/loongarch64/hostdep.h @@ -8,4 +8,27 @@ #ifndef LOONGARCH64_HOSTDEP_H #define LOONGARCH64_HOSTDEP_H +/* We have a safe-syscall.inc.S */ +#define HAVE_SAFE_SYSCALL + +#ifndef __ASSEMBLER__ + +/* These are defined by the safe-syscall.inc.S file */ +extern char safe_syscall_start[]; +extern char safe_syscall_end[]; + +/* Adjust the signal context to rewind out of safe-syscall if we're in it */ +static inline void rewind_if_in_safe_syscall(void *puc) +{ + ucontext_t *uc = puc; + unsigned long long *pcreg = &uc->uc_mcontext.__pc; + + if (*pcreg > (uintptr_t)safe_syscall_start + && *pcreg < (uintptr_t)safe_syscall_end) { + *pcreg = (uintptr_t)safe_syscall_start; + } +} + +#endif /* __ASSEMBLER__ */ + #endif diff --git a/linux-user/host/loongarch64/safe-syscall.inc.S b/linux-user/host/loongarch64/safe-syscall.inc.S new file mode 100644 index 0000000..bb53024 --- /dev/null +++ b/linux-user/host/loongarch64/safe-syscall.inc.S @@ -0,0 +1,80 @@ +/* + * safe-syscall.inc.S : host-specific assembly fragment + * to handle signals occurring at the same time as system calls. + * This is intended to be included by linux-user/safe-syscall.S + * + * Ported to LoongArch by WANG Xuerui + * + * Based on safe-syscall.inc.S code for every other architecture, + * originally written by Richard Henderson + * Copyright (C) 2018 Linaro, Inc. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + + .global safe_syscall_base + .global safe_syscall_start + .global safe_syscall_end + .type safe_syscall_base, @function + .type safe_syscall_start, @function + .type safe_syscall_end, @function + + /* + * This is the entry point for making a system call. The calling + * convention here is that of a C varargs function with the + * first argument an 'int *' to the signal_pending flag, the + * second one the system call number (as a 'long'), and all further + * arguments being syscall arguments (also 'long'). + * We return a long which is the syscall's return value, which + * may be negative-errno on failure. Conversion to the + * -1-and-errno-set convention is done by the calling wrapper. + */ +safe_syscall_base: + .cfi_startproc + /* + * The syscall calling convention is nearly the same as C: + * we enter with a0 == *signal_pending + * a1 == syscall number + * a2 ... a7 == syscall arguments + * and return the result in a0 + * and the syscall instruction needs + * a7 == syscall number + * a0 ... a5 == syscall arguments + * and returns the result in a0 + * Shuffle everything around appropriately. + */ + move $t0, $a0 /* signal_pending pointer */ + move $t1, $a1 /* syscall number */ + move $a0, $a2 /* syscall arguments */ + move $a1, $a3 + move $a2, $a4 + move $a3, $a5 + move $a4, $a6 + move $a5, $a7 + move $a7, $t1 + + /* + * This next sequence of code works in conjunction with the + * rewind_if_safe_syscall_function(). If a signal is taken + * and the interrupted PC is anywhere between 'safe_syscall_start' + * and 'safe_syscall_end' then we rewind it to 'safe_syscall_start'. + * The code sequence must therefore be able to cope with this, and + * the syscall instruction must be the final one in the sequence. + */ +safe_syscall_start: + /* If signal_pending is non-zero, don't do the call */ + ld.w $t1, $t0, 0 + bnez $t1, 0f + syscall 0 +safe_syscall_end: + /* code path for having successfully executed the syscall */ + jr $ra + +0: + /* code path when we didn't execute the syscall */ + li.w $a0, -TARGET_ERESTARTSYS + jr $ra + .cfi_endproc + + .size safe_syscall_base, .-safe_syscall_base