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=unavailable 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 6B161C4727F for ; Tue, 29 Sep 2020 11:53:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28ADA206CA for ; Tue, 29 Sep 2020 11:53:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601380420; bh=qBx7cPjzZCuHyLGD9yeEbvIMCmbuJNrA95mv/2qo/iE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AQVqElbAySedsobRR4DKmrMTaBUYWvMHQ+NJvMbaQL+PR+cy8nhRtMOcWGnRUeim9 W1VetQkGbqbSVSUKOxtWvmhh5jdF9mvpnrAUs7MiVBRKOu7os1qcRkosiw9p0VIQE8 AccfFJj1z+6odW+8PrH1JW4JiNIe+Qc760RW/euY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731444AbgI2Lxi (ORCPT ); Tue, 29 Sep 2020 07:53:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:47384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731044AbgI2Lq7 (ORCPT ); Tue, 29 Sep 2020 07:46:59 -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 97B7A2074A; Tue, 29 Sep 2020 11:46:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601380007; bh=qBx7cPjzZCuHyLGD9yeEbvIMCmbuJNrA95mv/2qo/iE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nDUwWsha1/KX7gUkhQeAu2lzFYMIgeDWZTw5KdmvVpuCRqrqpndKAKuNjmPWilBk9 3/MEcvbr9EDrJ46yoB6PP1VPqALAPE0MI+eQebvdGu0JvTMWUSUfwkGRPKv46qwCG+ dYVnQrpr+AdWDPwhn/xCWY7NgenRMqngBIgipbNM= 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 5.8 07/99] RISC-V: Take text_mutex in ftrace_init_nop() Date: Tue, 29 Sep 2020 13:00:50 +0200 Message-Id: <20200929105930.079643749@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105929.719230296@linuxfoundation.org> References: <20200929105929.719230296@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: linux-kernel@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 ace8a6e2d11d3..845002cc2e571 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -66,6 +66,13 @@ 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 #endif /* _ASM_RISCV_FTRACE_H */ diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index 2ff63d0cbb500..99e12faa54986 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -97,6 +97,25 @@ 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