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 X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF699C4727F for ; Tue, 29 Sep 2020 11:36:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 911BA23B8A for ; Tue, 29 Sep 2020 11:36:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379397; bh=MdUKsgIK7/XLrFbqnswTNRxhEGOstKAHiiyS57mqC18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Y5gxdF3WE6GgQ37fsXnD65cNTMEL7zggeq7rBwwVkD9VS3Qvh6xxQD7UQMez0zCvq S+uW/pEDGIRhS6mmvp9e+D5JXbwXytifBENaxUUOkJv1AB4jXR2kE2NYczBxfKJ420 ovt0uk72VR4A54qnewZQq+DcJmrZhqH/3imjsXUk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728602AbgI2Lgg (ORCPT ); Tue, 29 Sep 2020 07:36:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:49162 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729907AbgI2Lft (ORCPT ); Tue, 29 Sep 2020 07:35:49 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 29CF223D97; Tue, 29 Sep 2020 11:30:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379052; bh=MdUKsgIK7/XLrFbqnswTNRxhEGOstKAHiiyS57mqC18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rL4HUvE+oHC1Qa8Ho9hiUVI4x6ayjGMyYkytoBr9InuNb/VrPWYnnVz0wlNOmZkOz u9zTXEuQf7ve6+rUrK6wwYDKp6w44nXnZVQoRoY9GBUnk9nXcLQR3SrgzBEqHl7eKm CfwimOwAZ+3AIGXOX+1F0TBJZLTfPV3z3Zqwb1Ok= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Palmer Dabbelt , Guo Ren , Sasha Levin Subject: [PATCH 4.19 209/245] RISC-V: Take text_mutex in ftrace_init_nop() Date: Tue, 29 Sep 2020 13:01:00 +0200 Message-Id: <20200929105957.146781978@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105946.978650816@linuxfoundation.org> References: <20200929105946.978650816@linuxfoundation.org> User-Agent: quilt/0.66 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: Palmer Dabbelt [ Upstream commit 66d18dbda8469a944dfec6c49d26d5946efba218 ] Without this we get lockdep failures. They're spurious failures as SMP isn't up when ftrace_init_nop() is called. As far as I can tell the easiest fix is to just take the lock, which also seems like the safest fix. Signed-off-by: Palmer Dabbelt Acked-by: Guo Ren Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin --- arch/riscv/include/asm/ftrace.h | 7 +++++++ arch/riscv/kernel/ftrace.c | 19 +++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index c6dcc5291f972..02fbc175142e2 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -63,4 +63,11 @@ do { \ * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here. */ #define MCOUNT_INSN_SIZE 8 + +#ifndef __ASSEMBLY__ +struct dyn_ftrace; +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); +#define ftrace_init_nop ftrace_init_nop +#endif + #endif diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index 6d39f64e4dce4..fa8530f05ed4f 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -88,6 +88,25 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, return __ftrace_modify_call(rec->ip, addr, false); } + +/* + * This is called early on, and isn't wrapped by + * ftrace_arch_code_modify_{prepare,post_process}() and therefor doesn't hold + * text_mutex, which triggers a lockdep failure. SMP isn't running so we could + * just directly poke the text, but it's simpler to just take the lock + * ourselves. + */ +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) +{ + int out; + + ftrace_arch_code_modify_prepare(); + out = ftrace_make_nop(mod, rec, MCOUNT_ADDR); + ftrace_arch_code_modify_post_process(); + + return out; +} + int ftrace_update_ftrace_func(ftrace_func_t func) { int ret = __ftrace_modify_call((unsigned long)&ftrace_call, -- 2.25.1