From patchwork Mon Sep 13 13:11:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 510528 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 48C50C433FE for ; Mon, 13 Sep 2021 14:21:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 336CE60555 for ; Mon, 13 Sep 2021 14:21:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344471AbhIMOW6 (ORCPT ); Mon, 13 Sep 2021 10:22:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:39370 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346164AbhIMOUq (ORCPT ); Mon, 13 Sep 2021 10:20:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7813860F58; Mon, 13 Sep 2021 13:46:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631540810; bh=UFRJs25GAxMiG7B0qj1s1sKyWGAdP0VM+21PtaJwPdQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pNCR2/SKr3toZrVnnDFy7yi7nkpWreenr8gi7N8qNsAQk8cLdh4H17y6Xw6CbbVQc Uu3TzioHZ1cwoxX/EoIV0AD4rzIkWSzCkU1Gjx/nvE0lk0KWbe/i3PIu1AkHJkDGzU G/oytNdtI6Gr2CYwVUgfyivWmNgI776QjhPXT3ok= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Oberparleiter , Heiko Carstens , Sasha Levin Subject: [PATCH 5.14 044/334] s390/debug: keep debug data on resize Date: Mon, 13 Sep 2021 15:11:38 +0200 Message-Id: <20210913131114.928470722@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131113.390368911@linuxfoundation.org> References: <20210913131113.390368911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Peter Oberparleiter [ Upstream commit 1204777867e8486a88dbb4793fe256b31ea05eeb ] Any previously recorded s390dbf debug data is reset when a debug area is resized using the 'pages' sysfs attribute. This can make live-debugging unnecessarily complex. Fix this by copying existing debug data to the newly allocated debug area when resizing. Signed-off-by: Peter Oberparleiter Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- arch/s390/kernel/debug.c | 74 ++++++++++++++++++++++++++++------------ 1 file changed, 53 insertions(+), 21 deletions(-) diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c index 09b6c6402f9b..0dbe48f550ff 100644 --- a/arch/s390/kernel/debug.c +++ b/arch/s390/kernel/debug.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -92,6 +93,8 @@ static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view, char *out_buf, const char *in_buf); static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view, char *out_buf, debug_sprintf_entry_t *curr_event); +static void debug_areas_swap(debug_info_t *a, debug_info_t *b); +static void debug_events_append(debug_info_t *dest, debug_info_t *src); /* globals */ @@ -726,35 +729,28 @@ EXPORT_SYMBOL(debug_unregister); */ static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area) { - debug_entry_t ***new_areas; + debug_info_t *new_id; unsigned long flags; - int rc = 0; if (!id || (nr_areas <= 0) || (pages_per_area < 0)) return -EINVAL; - if (pages_per_area > 0) { - new_areas = debug_areas_alloc(pages_per_area, nr_areas); - if (!new_areas) { - pr_info("Allocating memory for %i pages failed\n", - pages_per_area); - rc = -ENOMEM; - goto out; - } - } else { - new_areas = NULL; + + new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size, + id->level, ALL_AREAS); + if (!new_id) { + pr_info("Allocating memory for %i pages failed\n", + pages_per_area); + return -ENOMEM; } + spin_lock_irqsave(&id->lock, flags); - debug_areas_free(id); - id->areas = new_areas; - id->nr_areas = nr_areas; - id->pages_per_area = pages_per_area; - id->active_area = 0; - memset(id->active_entries, 0, sizeof(int)*id->nr_areas); - memset(id->active_pages, 0, sizeof(int)*id->nr_areas); + debug_events_append(new_id, id); + debug_areas_swap(new_id, id); + debug_info_free(new_id); spin_unlock_irqrestore(&id->lock, flags); pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area); -out: - return rc; + + return 0; } /** @@ -821,6 +817,42 @@ static inline debug_entry_t *get_active_entry(debug_info_t *id) id->active_entries[id->active_area]); } +/* Swap debug areas of a and b. */ +static void debug_areas_swap(debug_info_t *a, debug_info_t *b) +{ + swap(a->nr_areas, b->nr_areas); + swap(a->pages_per_area, b->pages_per_area); + swap(a->areas, b->areas); + swap(a->active_area, b->active_area); + swap(a->active_pages, b->active_pages); + swap(a->active_entries, b->active_entries); +} + +/* Append all debug events in active area from source to destination log. */ +static void debug_events_append(debug_info_t *dest, debug_info_t *src) +{ + debug_entry_t *from, *to, *last; + + if (!src->areas || !dest->areas) + return; + + /* Loop over all entries in src, starting with oldest. */ + from = get_active_entry(src); + last = from; + do { + if (from->clock != 0LL) { + to = get_active_entry(dest); + memset(to, 0, dest->entry_size); + memcpy(to, from, min(src->entry_size, + dest->entry_size)); + proceed_active_entry(dest); + } + + proceed_active_entry(src); + from = get_active_entry(src); + } while (from != last); +} + /* * debug_finish_entry: * - set timestamp, caller address, cpu number etc.