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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9ACDDC41513 for ; Wed, 26 Jul 2023 10:25:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233257AbjGZKZw (ORCPT ); Wed, 26 Jul 2023 06:25:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231317AbjGZKZt (ORCPT ); Wed, 26 Jul 2023 06:25:49 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFB2D211C for ; Wed, 26 Jul 2023 03:25:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690367104; 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: in-reply-to:in-reply-to:references:references; bh=36DJPnF7Pxv/d3UEUTkuVMdzn88ssz77HYYWsSAh9Ic=; b=IAmYAp8uaytcJBPeG7FmnuvHMVW7ejjvNHu0cjOJb3aqhTUgV5hlNWvJ20xafXdKwGwzEY maShbzt4jJYGJ5lro3PXVG6g/2aMv8zCRPyA9t7FOAD184eABGHG7eYivg+pX630bTxDFt XvsBGiEo3GLb1eEtnLfDELHGBQayIRg= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-223-VUxOp_ZdMMuuLuv-n4j8Yg-1; Wed, 26 Jul 2023 06:24:59 -0400 X-MC-Unique: VUxOp_ZdMMuuLuv-n4j8Yg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B84991C31C46; Wed, 26 Jul 2023 10:24:58 +0000 (UTC) Received: from localhost (ovpn-12-99.pek2.redhat.com [10.72.12.99]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AC8E62166B25; Wed, 26 Jul 2023 10:24:57 +0000 (UTC) Date: Wed, 26 Jul 2023 18:24:53 +0800 From: Baoquan He To: Chen Jiahao Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, kexec@lists.infradead.org, linux-doc@vger.kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, conor.dooley@microchip.com, guoren@kernel.org, heiko@sntech.de, bjorn@rivosinc.com, alex@ghiti.fr, akpm@linux-foundation.org, atishp@rivosinc.com, thunder.leizhen@huawei.com, horms@kernel.org Subject: Re: [PATCH -next v9 1/2] riscv: kdump: Implement crashkernel=X,[high,low] Message-ID: References: <20230726175000.2536220-1-chenjiahao16@huawei.com> <20230726175000.2536220-2-chenjiahao16@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230726175000.2536220-2-chenjiahao16@huawei.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26/23 at 05:49pm, Chen Jiahao wrote: > On riscv, the current crash kernel allocation logic is trying to > allocate within 32bit addressible memory region by default, if > failed, try to allocate without 4G restriction. > > In need of saving DMA zone memory while allocating a relatively large > crash kernel region, allocating the reserved memory top down in > high memory, without overlapping the DMA zone, is a mature solution. > Here introduce the parameter option crashkernel=X,[high,low]. > > One can reserve the crash kernel from high memory above DMA zone range > by explicitly passing "crashkernel=X,high"; or reserve a memory range > below 4G with "crashkernel=X,low". LGTM, Acked-by: Baoquan He > > Signed-off-by: Chen Jiahao > Acked-by: Guo Ren > --- > arch/riscv/kernel/setup.c | 5 +++ > arch/riscv/mm/init.c | 93 ++++++++++++++++++++++++++++++++++++--- > 2 files changed, 91 insertions(+), 7 deletions(-) > > diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c > index 971fe776e2f8..376f5d49ce85 100644 > --- a/arch/riscv/kernel/setup.c > +++ b/arch/riscv/kernel/setup.c > @@ -178,6 +178,11 @@ static void __init init_resources(void) > if (ret < 0) > goto error; > } > + if (crashk_low_res.start != crashk_low_res.end) { > + ret = add_resource(&iomem_resource, &crashk_low_res); > + if (ret < 0) > + goto error; > + } > #endif > > #ifdef CONFIG_CRASH_DUMP > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 70fb31960b63..156e09a1ceee 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -1297,6 +1297,28 @@ static inline void setup_vm_final(void) > } > #endif /* CONFIG_MMU */ > > +/* Reserve 128M low memory by default for swiotlb buffer */ > +#define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20) > + > +static int __init reserve_crashkernel_low(unsigned long long low_size) > +{ > + unsigned long long low_base; > + > + low_base = memblock_phys_alloc_range(low_size, PMD_SIZE, 0, dma32_phys_limit); > + if (!low_base) { > + pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size); > + return -ENOMEM; > + } > + > + pr_info("crashkernel low memory reserved: 0x%016llx - 0x%016llx (%lld MB)\n", > + low_base, low_base + low_size, low_size >> 20); > + > + crashk_low_res.start = low_base; > + crashk_low_res.end = low_base + low_size - 1; > + > + return 0; > +} > + > /* > * reserve_crashkernel() - reserves memory for crash kernel > * > @@ -1308,8 +1330,12 @@ static void __init reserve_crashkernel(void) > { > unsigned long long crash_base = 0; > unsigned long long crash_size = 0; > + unsigned long long crash_low_size = 0; > unsigned long search_start = memblock_start_of_DRAM(); > - unsigned long search_end = memblock_end_of_DRAM(); > + unsigned long search_end = (unsigned long)dma32_phys_limit; > + char *cmdline = boot_command_line; > + bool fixed_base = false; > + bool high = false; > > int ret = 0; > > @@ -1325,14 +1351,36 @@ static void __init reserve_crashkernel(void) > return; > } > > - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), > + ret = parse_crashkernel(cmdline, memblock_phys_mem_size(), > &crash_size, &crash_base); > - if (ret || !crash_size) > + if (ret == -ENOENT) { > + /* Fallback to crashkernel=X,[high,low] */ > + ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base); > + if (ret || !crash_size) > + return; > + > + /* > + * crashkernel=Y,low is valid only when crashkernel=X,high > + * is passed. > + */ > + ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base); > + if (ret == -ENOENT) > + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; > + else if (ret) > + return; > + > + search_start = (unsigned long)dma32_phys_limit; > + search_end = memblock_end_of_DRAM(); > + high = true; > + } else if (ret || !crash_size) { > + /* Invalid argument value specified */ > return; > + } > > crash_size = PAGE_ALIGN(crash_size); > > if (crash_base) { > + fixed_base = true; > search_start = crash_base; > search_end = crash_base + crash_size; > } > @@ -1345,12 +1393,37 @@ static void __init reserve_crashkernel(void) > * swiotlb can work on the crash kernel. > */ > crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE, > - search_start, > - min(search_end, (unsigned long) SZ_4G)); > + search_start, search_end); > if (crash_base == 0) { > - /* Try again without restricting region to 32bit addressible memory */ > + /* > + * For crashkernel=size[KMG]@offset[KMG], print out failure > + * message if can't reserve the specified region. > + */ > + if (fixed_base) { > + pr_warn("crashkernel: allocating failed with given size@offset\n"); > + return; > + } > + > + if (high) { > + /* > + * For crashkernel=size[KMG],high, if the first attempt was > + * for high memory, fall back to low memory. > + */ > + search_start = memblock_start_of_DRAM(); > + search_end = (unsigned long)dma32_phys_limit; > + } else { > + /* > + * For crashkernel=size[KMG], if the first attempt was for > + * low memory, fall back to high memory, the minimum required > + * low memory will be reserved later. > + */ > + search_start = (unsigned long)dma32_phys_limit; > + search_end = memblock_end_of_DRAM(); > + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; > + } > + > crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE, > - search_start, search_end); > + search_start, search_end); > if (crash_base == 0) { > pr_warn("crashkernel: couldn't allocate %lldKB\n", > crash_size >> 10); > @@ -1358,6 +1431,12 @@ static void __init reserve_crashkernel(void) > } > } > > + if ((crash_base >= dma32_phys_limit) && crash_low_size && > + reserve_crashkernel_low(crash_low_size)) { > + memblock_phys_free(crash_base, crash_size); > + return; > + } > + > pr_info("crashkernel: reserved 0x%016llx - 0x%016llx (%lld MB)\n", > crash_base, crash_base + crash_size, crash_size >> 20); > > -- > 2.34.1 >