From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 763F21AAE02; Mon, 14 Oct 2024 14:40:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728916845; cv=none; b=ETfknoDyB6+gN1MA98oOrBvyiLv7mVtrNYuIZSNgzrCamNn6uBZfKFq6ORpJT2Dz5z5XOiGzJdCQFRBfacOxlicoaKaqw02cufFPeVFOMqsq8ej+kKXtKEldun2Rez7Df7twr/Ogyqh97BRVyb45E7vExEjUwrNLZIurytrxox0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728916845; c=relaxed/simple; bh=x08vG0fTSPW1ZqUObQmiKfH9Rxh46tF6HLgVPccN3w8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eNKMN/BO3QflWuARUiHuqrtEvutGu2bbuElShoXKGJ+u98DCqK1vKhCUvmC9w4nT7/haJTvVHTuWVyBIRMGfOvka9YzX2nQ+vBuLzsvQlg9X8qYnyw2q81RYKv1quu7KlGgE/v788Y4A6LlT7GiAL425JzjY8sYSowpv+GH30JQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iRAslA6V; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="iRAslA6V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 692E4C4CEC3; Mon, 14 Oct 2024 14:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728916845; bh=x08vG0fTSPW1ZqUObQmiKfH9Rxh46tF6HLgVPccN3w8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iRAslA6Vv4mk8B0ZZRa6CBzq65vVevkj5bs/A/Ren1JiXi9zinHWnyshXgyhFwMsx F6C/puiqI8VjrR3xk75ySpxbT04C54yJTGqGRAVyh3Rg1zTRWHAENQRj/Be9zF2Y0Z k1/QX2HhHQbhp1LAZKV1D/R69TfFyRLiqfbFWKuM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jisheng Zhang , Cyril Bur , Palmer Dabbelt , Sasha Levin Subject: [PATCH 6.6 081/213] riscv: avoid Imbalance in RAS Date: Mon, 14 Oct 2024 16:19:47 +0200 Message-ID: <20241014141046.140595341@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241014141042.954319779@linuxfoundation.org> References: <20241014141042.954319779@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jisheng Zhang [ Upstream commit 8f1534e7440382d118c3d655d3a6014128b2086d ] Inspired by[1], modify the code to remove the code of modifying ra to avoid imbalance RAS (return address stack) which may lead to incorret predictions on return. Link: https://lore.kernel.org/linux-riscv/20240607061335.2197383-1-cyrilbur@tenstorrent.com/ [1] Signed-off-by: Jisheng Zhang Reviewed-by: Cyril Bur Link: https://lore.kernel.org/r/20240720170659.1522-1-jszhang@kernel.org Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin --- arch/riscv/kernel/entry.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index ed7baf2cf7e87..1f90fee24a8ba 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -219,8 +219,8 @@ SYM_CODE_START(ret_from_fork) jalr s0 1: move a0, sp /* pt_regs */ - la ra, ret_from_exception - tail syscall_exit_to_user_mode + call syscall_exit_to_user_mode + j ret_from_exception SYM_CODE_END(ret_from_fork) /* -- 2.43.0