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=-14.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 00BC0C43469 for ; Mon, 21 Sep 2020 14:41:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA20F221EC for ; Mon, 21 Sep 2020 14:41:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699307; bh=MdUKsgIK7/XLrFbqnswTNRxhEGOstKAHiiyS57mqC18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1KU6gl5Nn1wkFw/gdK/mndtqavvJ9QvAiSeekSYeJF4rvidvOVyMrSG0Moea8L0bc DI9SuKnUWttpzPre0ZazbjqDrk7+o6CnZjTPSo+F+t98Purq3jKo1v1+HgxTFXaXdF WslIjxHyBZ9CLCQIl9fqgWINHfdPweqFtp3lm/1s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727956AbgIUOle (ORCPT ); Mon, 21 Sep 2020 10:41:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:50730 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728029AbgIUOlZ (ORCPT ); Mon, 21 Sep 2020 10:41:25 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D9AC52389F; Mon, 21 Sep 2020 14:41:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699280; bh=MdUKsgIK7/XLrFbqnswTNRxhEGOstKAHiiyS57mqC18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g4Bfoo1ZWu+aC/1H+Lk6I2oAfYGP5NGbjgFcfBqgqx9Miv58+7u9HJ8KP+YUsLAFT Sm8vnooGYhM4uLbm1UlZxvhlhZL462WaqDdCSdYffZEBdcktDq/3rLI8Lcthswa1gR UYlzF0qvYX//2MJdAbgsgFmTMw7L36uxtFT2GpJo= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Palmer Dabbelt , Guo Ren , Sasha Levin , linux-riscv@lists.infradead.org Subject: [PATCH AUTOSEL 4.19 4/9] RISC-V: Take text_mutex in ftrace_init_nop() Date: Mon, 21 Sep 2020 10:41:09 -0400 Message-Id: <20200921144114.2135773-4-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200921144114.2135773-1-sashal@kernel.org> References: <20200921144114.2135773-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 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