From patchwork Tue Nov 14 09:16:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 13455012 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 210BEC072A2 for ; Tue, 14 Nov 2023 09:17:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZnMt4A1tOL0jhHbSMaTehsGi+SFz1fmsLlsjyVwZE7o=; b=lefUDMHJ0vZUaK GaeAUmoNzVTIM337lPzrXCfToiTCNtKwKfgWyFUadlKY5VJfrITuT0QaJQS4aV4V6v7lecqcy+1xj VYsvU1f5tAS561APQlmCrF13xU2We5/PsjsmqQz3mX6QTG7qw5UYZOnoswISCTC1bt4D5qy2wtau+ J7FiaA6bnnEa1zY0NUjf5TAzvtcYesUim5xD2lVfFRzKQg//SlJVlzK8dIa1X6uj9KvA9f2T8/QU8 38zmo0u8hBVGJ8njlK4DsGQWx4bbMYvP1yXnVt8aFrzPEO9sxM1rpuBkV1oOVn5txGu7miJEFVFHb bKztTHLImykkckICmwPw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r2pXu-00FUB7-1K; Tue, 14 Nov 2023 09:17:22 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1r2pXr-00FU8q-2v for linux-riscv@lists.infradead.org; Tue, 14 Nov 2023 09:17:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1699953439; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FCQMK3tvMnlcAutGAmjADx8NXWTNg1Te+2YY/zMRKiU=; b=UOXWY2Wb5epXuiGqQH9cxn/kj6gjrvbmGwh+n0F1HXq6gqlZg9fJ0i9tkL2u0Bah+USKB5 /ytg2GeEM4neBQFyJvFHoptZD9YkpHjhWvxr4UMK/fB7VaYj5Oi/7nBGF27FmjTkcoN2zJ 0NjYFIF6gRIEVY99tkj9g9ZMv5p0ZjA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-155-AtEvHmVsOLW5Ae-g10RPxA-1; Tue, 14 Nov 2023 04:17:15 -0500 X-MC-Unique: AtEvHmVsOLW5Ae-g10RPxA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EB275101A53B; Tue, 14 Nov 2023 09:17:14 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.112.231]) by smtp.corp.redhat.com (Postfix) with ESMTP id E3A2D2166B26; Tue, 14 Nov 2023 09:17:10 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org, x86@kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, akpm@linux-foundation.org, ebiederm@xmission.com, takahiro.akashi@linaro.org, Baoquan He Subject: [PATCH 2/2] kexec_file: Load kernel at top of system RAM if required Date: Tue, 14 Nov 2023 17:16:58 +0800 Message-ID: <20231114091658.228030-3-bhe@redhat.com> In-Reply-To: <20231114091658.228030-1-bhe@redhat.com> References: <20231114091658.228030-1-bhe@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231114_011720_021355_E171EE0B X-CRM114-Status: GOOD ( 10.34 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Kexec_load interface has been doing top down searching and loading kernel/initrd/purgtory etc to prepare for kexec reboot. In that way, the benefits are that it avoids to consume and fragment limited low memory which satisfy DMA buffer allocation and big chunk of continuous memory during system init; and avoids to stir with BIOS/FW reserved or occupied areas, or corner case handling/work around/quirk occupied areas when doing system init. By the way, the top-down searching and loading of kexec-ed kernel is done in user space utility code. For kexec_file loading, even if kexec_buf.top_down is 'true', it's simply ignored. It calls walk_system_ram_res() directly to go through all resources of System RAM bottom up, to find an available memory region, then call locate_mem_hole_callback() to allocate memory in that found memory region from top to down. This is not expected and inconsistent with kexec_load. Here check if kexec_buf.top_down is 'true' in kexec_walk_resources(), if yes, call the newly added walk_system_ram_res_rev() to find memory region of system RAM from top to down to load kernel/initrd etc. Signed-off-by: Baoquan He --- kernel/kexec_file.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index f9a419cd22d4..ba3ef30921b8 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -592,6 +592,8 @@ static int kexec_walk_resources(struct kexec_buf *kbuf, IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, crashk_res.start, crashk_res.end, kbuf, func); + else if (kbuf->top_down) + return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func); else return walk_system_ram_res(0, ULONG_MAX, kbuf, func); }