From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E17DDC76188 for ; Mon, 3 Apr 2023 14:35:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233590AbjDCOf3 (ORCPT ); Mon, 3 Apr 2023 10:35:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233565AbjDCOf1 (ORCPT ); Mon, 3 Apr 2023 10:35:27 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0E08EF88 for ; Mon, 3 Apr 2023 07:35:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 864B7B81CA0 for ; Mon, 3 Apr 2023 14:35:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF7DFC4339B; Mon, 3 Apr 2023 14:35:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680532523; bh=mMZl9Vi4nPwhVrUiv1pJsBG2yi9AgwwPmCWL0tI4Ka4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EHP0Chm2q5xwX9ECU+BBRhhZb+z5MkY8GwN7QOhwZJ8+y7G7udzhGIaFSbvkgtE36 fvsupKQXeYrwWgt9+Br0dOOcUPTeBEhf0oidNq7IE/CpccL318srvSH9G7Huq1HGEU uQ0gpI0dr8yoKV92MZdMeZMyUjmIZUJRvMUiXtE0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andy Chiu , Guo Ren , Palmer Dabbelt , Sasha Levin Subject: [PATCH 6.1 016/181] riscv: ftrace: Fixup panic by disabling preemption Date: Mon, 3 Apr 2023 16:07:31 +0200 Message-Id: <20230403140415.648037204@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230403140415.090615502@linuxfoundation.org> References: <20230403140415.090615502@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andy Chiu [ Upstream commit 8547649981e6631328cd64f583667501ae385531 ] In RISCV, we must use an AUIPC + JALR pair to encode an immediate, forming a jump that jumps to an address over 4K. This may cause errors if we want to enable kernel preemption and remove dependency from patching code with stop_machine(). For example, if a task was switched out on auipc. And, if we changed the ftrace function before it was switched back, then it would jump to an address that has updated 11:0 bits mixing with previous XLEN:12 part. p: patched area performed by dynamic ftrace ftrace_prologue: p| REG_S ra, -SZREG(sp) p| auipc ra, 0x? ------------> preempted ... change ftrace function ... p| jalr -?(ra) <------------- switched back p| REG_L ra, -SZREG(sp) func: xxx ret Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT") Signed-off-by: Andy Chiu Signed-off-by: Guo Ren Link: https://lore.kernel.org/r/20230112090603.1295340-2-guoren@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin --- arch/riscv/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index ae11d5647f9d4..06b9b2f60b9fb 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -278,7 +278,7 @@ config ARCH_RV64I select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL select HAVE_FUNCTION_GRAPH_TRACER - select HAVE_FUNCTION_TRACER if !XIP_KERNEL + select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION select SWIOTLB if MMU endchoice -- 2.39.2