From patchwork Mon Nov 22 10:41:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: WANG Xuerui X-Patchwork-Id: 12631653 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 66F99C433F5 for ; Mon, 22 Nov 2021 11:07:20 +0000 (UTC) Received: from localhost ([::1]:37506 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mp7AN-0008W9-Iv for qemu-devel@archiver.kernel.org; Mon, 22 Nov 2021 06:07:19 -0500 Received: from eggs.gnu.org ([209.51.188.92]:53008) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mp6nM-000233-GY for qemu-devel@nongnu.org; Mon, 22 Nov 2021 05:43:33 -0500 Received: from mail.xen0n.name ([115.28.160.31]:40912 helo=mailbox.box.xen0n.name) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mp6nH-0007jD-IK for qemu-devel@nongnu.org; Mon, 22 Nov 2021 05:43:30 -0500 Received: from ld50.lan (unknown [101.88.31.179]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by mailbox.box.xen0n.name (Postfix) with ESMTPSA id B0F4D60B05; Mon, 22 Nov 2021 18:42:56 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=xen0n.name; s=mail; t=1637577777; bh=Y3nJxiz3rtVGiB2s1Z3MmbsHG1ZNEXNrDVtvdvw1MQ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cjuj9WJHTWEQqf0rmzKYo229LzvOjSOacUxmQSVOrZhGUuhM+rgNxiZUhsJ2eNWKl rFJSdUpCSt0jTiZkJXxHLAtkTGVKxjGdLvN5kQCGooKSFyeU0OSzR84fXhXqfAeXub n6V0rk912eKHIK1WipzFEyO9fRfqeouqWNPoVlRU= From: WANG Xuerui To: qemu-devel@nongnu.org Subject: [PATCH v7 28/31] linux-user: Add safe syscall handling for loongarch64 hosts Date: Mon, 22 Nov 2021 18:41:58 +0800 Message-Id: <20211122104201.112695-29-git@xen0n.name> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211122104201.112695-1-git@xen0n.name> References: <20211122104201.112695-1-git@xen0n.name> MIME-Version: 1.0 Received-SPF: pass client-ip=115.28.160.31; envelope-from=git@xen0n.name; helo=mailbox.box.xen0n.name X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=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 , XiaoJuan Yang , Richard Henderson , =?utf-8?q?Philippe_Mathie?= =?utf-8?q?u-Daud=C3=A9?= , Laurent Vivier , WANG Xuerui , =?utf-8?q?Alex_Benn=C3=A9e?= , Song Gao Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Signed-off-by: WANG Xuerui Reviewed-by: Richard Henderson --- linux-user/host/loongarch64/hostdep.h | 34 ++++++++ .../host/loongarch64/safe-syscall.inc.S | 80 +++++++++++++++++++ 2 files changed, 114 insertions(+) create mode 100644 linux-user/host/loongarch64/hostdep.h 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 new file mode 100644 index 0000000000..e3d5fa703f --- /dev/null +++ b/linux-user/host/loongarch64/hostdep.h @@ -0,0 +1,34 @@ +/* + * hostdep.h : things which are dependent on the host architecture + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#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 0000000000..bb530248b3 --- /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