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 D3C371E2834; Fri, 4 Oct 2024 18:19:41 +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=1728065981; cv=none; b=hILjX1SKdkCDs0rFSUtXO4ZgsBXJ8aqXAvawUvzLV7LNfIqrNxn0DTRz1AZY5vt/pXQx1YUDheUcfQOKDLhZ7icTvMlbWlR+ok9yewAljhVfRDiW+2gMe+INUnhV0id5/Fe2/wmmo6Z6gDQbPUTvbS5c6R1+VJ44kUM1Jsy7rIQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728065981; c=relaxed/simple; bh=/B2Gc/EMzBDQckZ37mMVoHmmOAbe4wh83yczyv1hib4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tKi3K0Ea6us3fcb806/ilOgTCPjwaBnZW5Zbd6wg4k9AqfZZ+FJMj7bT3VVDKwuTKLws/j8hpWn7jRv7oqmJtAAli5PSlN4mGFqoUI71mq7fO99w6sNqx0XaDipTRdnLBTxk6/UKhUnA3Yn9WLsj3hSCzqWuH3q90fqyhI/uPr8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QRpR0qAH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QRpR0qAH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC948C4CECC; Fri, 4 Oct 2024 18:19:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728065981; bh=/B2Gc/EMzBDQckZ37mMVoHmmOAbe4wh83yczyv1hib4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QRpR0qAH6GYeq6glzx9ToEMJfToDw4n7+EdDkIbcHzr1A/OQgVsXzRf9AooKXMkRU TTZJJp9qwPAS2sHtJ9t7PXSpmWUZqKLPI8vzZB//wlNdmqho4LIPvZd4PtaZX1xAK/ icGetN0JwzyZn4AVy6XBJfkyAy8wCbKb5FrXEBUBwH5dOdOHNAtERiSpNJX+6NIrDT sxJQlBXnVkXIMQ9V1A/hDRegPYPqBj1XVykte4eSHwN4flwHir97fm/d8NPQYaSAHG DGTyHaUVMJNFGJUrYlcQooc7t5s7LztOwCgYPpNvS00rEqqCui0DGnC96kMryY4dwX t7hz8u2rzGpOA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jisheng Zhang , Cyril Bur , Palmer Dabbelt , Sasha Levin , paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, samitolvanen@google.com, cleger@rivosinc.com, guoren@kernel.org, namcaov@gmail.com, debug@rivosinc.com, antonb@tenstorrent.com, andy.chiu@sifive.com, linux-riscv@lists.infradead.org Subject: [PATCH AUTOSEL 6.11 38/76] riscv: avoid Imbalance in RAS Date: Fri, 4 Oct 2024 14:16:55 -0400 Message-ID: <20241004181828.3669209-38-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241004181828.3669209-1-sashal@kernel.org> References: <20241004181828.3669209-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.11.2 Content-Transfer-Encoding: 8bit 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 ac2e908d4418d..fefb8e7d957a0 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -239,8 +239,8 @@ 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) #ifdef CONFIG_IRQ_STACKS -- 2.43.0