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 68CB9C6FD18 for ; Wed, 29 Mar 2023 11:20:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229775AbjC2LUe (ORCPT ); Wed, 29 Mar 2023 07:20:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229531AbjC2LUc (ORCPT ); Wed, 29 Mar 2023 07:20:32 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E2974214 for ; Wed, 29 Mar 2023 04:19:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680088780; 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; 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charset=us-ascii Content-Disposition: inline In-Reply-To: <20230328115150.2700016-2-chenjiahao16@huawei.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 03/28/23 at 07:51pm, 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". > > Signed-off-by: Chen Jiahao > --- > arch/riscv/kernel/setup.c | 5 ++++ > arch/riscv/mm/init.c | 63 ++++++++++++++++++++++++++++++++++++--- > 2 files changed, 64 insertions(+), 4 deletions(-) > > diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c > index 5d3184cbf518..ea84e5047c23 100644 > --- a/arch/riscv/kernel/setup.c > +++ b/arch/riscv/kernel/setup.c > @@ -176,6 +176,11 @@ 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 478d6763a01a..b7708cc467fa 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -1152,6 +1152,28 @@ 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 > * > @@ -1163,6 +1185,7 @@ 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(); > > @@ -1182,8 +1205,30 @@ static void __init reserve_crashkernel(void) > > ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), > &crash_size, &crash_base); > - if (ret || !crash_size) > + if (ret == -ENOENT) { > + /* > + * crashkernel=X,[high,low] can be specified or not, but > + * invalid value is not allowed. > + */ > + ret = parse_crashkernel_high(boot_command_line, 0, &crash_size, &crash_base); I would add a local variable to assign boot_command_line to it just like arm64 does. Then these lines could be shorter. char *cmdline = boot_command_line; > + if (ret || !crash_size) > + return; > + > + /* > + * crashkernel=Y,low is valid only when crashkernel=X,high > + * is passed and high memory is reserved successful. > + */ > + ret = parse_crashkernel_low(boot_command_line, 0, &crash_low_size, &crash_base); > + if (ret == -ENOENT) > + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; > + else if (ret) > + return; > + > + search_start = dma32_phys_limit; > + } else if (ret || !crash_size) { > + /* Invalid argument value specified */ > return; > + } > > crash_size = PAGE_ALIGN(crash_size); > > @@ -1201,16 +1246,26 @@ static void __init reserve_crashkernel(void) > */ > crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE, > search_start, > - min(search_end, (unsigned long) SZ_4G)); > + min(search_end, (unsigned long)dma32_phys_limit)); > if (crash_base == 0) { The above conditional check isn't right. If crashkernel=size@offset specified, the reservation failure won't trigger retry. This seems to be originally introduced by old commit, while this need be fixed firstly. > - /* Try again without restricting region to 32bit addressible memory */ > + /* Try again above the region of 32bit addressible memory */ > crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE, > - search_start, search_end); > + max(search_start, (unsigned long)dma32_phys_limit), > + search_end); > if (crash_base == 0) { > pr_warn("crashkernel: couldn't allocate %lldKB\n", > crash_size >> 10); > return; > } > + > + if (!crash_low_size) > + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; > + } > + > + if ((crash_base > dma32_phys_limit - crash_low_size) && > + 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", > -- > 2.31.1 >