From nobody Wed Feb 11 18:27:19 2026 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 DF841C77B73 for ; Mon, 10 Apr 2023 13:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229777AbjDJNGN (ORCPT ); Mon, 10 Apr 2023 09:06:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229718AbjDJNGK (ORCPT ); Mon, 10 Apr 2023 09:06:10 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE8CF4488; Mon, 10 Apr 2023 06:06:07 -0700 (PDT) Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.54]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4Pw8Jk729bz17Rw5; Mon, 10 Apr 2023 21:02:30 +0800 (CST) Received: from huawei.com (10.67.174.205) by dggpemm500016.china.huawei.com (7.185.36.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Mon, 10 Apr 2023 21:06:02 +0800 From: Chen Jiahao To: , , , CC: , , , , , , , , , , , Subject: [PATCH -next v4 1/2] riscv: kdump: Implement crashkernel=X,[high,low] Date: Mon, 10 Apr 2023 21:05:52 +0800 Message-ID: <20230410130553.3226347-2-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230410130553.3226347-1-chenjiahao16@huawei.com> References: <20230410130553.3226347-1-chenjiahao16@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.67.174.205] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500016.china.huawei.com (7.185.36.25) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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=3DX,[high,low]. One can reserve the crash kernel from high memory above DMA zone range by explicitly passing "crashkernel=3DX,high"; or reserve a memory range below 4G with "crashkernel=3DX,low". Signed-off-by: Chen Jiahao Acked-by: Guo Ren Reviewed-by: Zhen Lei Reviewed-by: Simon Horman --- arch/riscv/kernel/setup.c | 5 +++ arch/riscv/mm/init.c | 71 ++++++++++++++++++++++++++++++++++++--- 2 files changed, 71 insertions(+), 5 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 !=3D crashk_low_res.end) { + ret =3D add_resource(&iomem_resource, &crashk_low_res); + if (ret < 0) + goto error; + } #endif =20 #ifdef CONFIG_CRASH_DUMP diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 478d6763a01a..70f6cb281ed1 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 */ =20 +/* 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 =3D 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_si= ze); + 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 =3D low_base; + crashk_low_res.end =3D low_base + low_size - 1; + + return 0; +} + /* * reserve_crashkernel() - reserves memory for crash kernel * @@ -1163,8 +1185,12 @@ static void __init reserve_crashkernel(void) { unsigned long long crash_base =3D 0; unsigned long long crash_size =3D 0; + unsigned long long crash_low_size =3D 0; unsigned long search_start =3D memblock_start_of_DRAM(); unsigned long search_end =3D memblock_end_of_DRAM(); + unsigned long search_low_max =3D (unsigned long)dma32_phys_limit; + char *cmdline =3D boot_command_line; + bool fixed_base =3D false; =20 int ret =3D 0; =20 @@ -1180,14 +1206,34 @@ static void __init reserve_crashkernel(void) return; } =20 - ret =3D parse_crashkernel(boot_command_line, memblock_phys_mem_size(), + ret =3D parse_crashkernel(cmdline, memblock_phys_mem_size(), &crash_size, &crash_base); - if (ret || !crash_size) + if (ret =3D=3D -ENOENT) { + /* Fallback to crashkernel=3DX,[high,low] */ + ret =3D parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base); + if (ret || !crash_size) + return; + + /* + * crashkernel=3DY,low is valid only when crashkernel=3DX,high + * is passed. + */ + ret =3D parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base); + if (ret =3D=3D -ENOENT) + crash_low_size =3D DEFAULT_CRASH_KERNEL_LOW_SIZE; + else if (ret) + return; + + search_start =3D search_low_max; + } else if (ret || !crash_size) { + /* Invalid argument value specified */ return; + } =20 crash_size =3D PAGE_ALIGN(crash_size); =20 if (crash_base) { + fixed_base =3D true; search_start =3D crash_base; search_end =3D crash_base + crash_size; } @@ -1201,16 +1247,31 @@ static void __init reserve_crashkernel(void) */ crash_base =3D memblock_phys_alloc_range(crash_size, PMD_SIZE, search_start, - min(search_end, (unsigned long) SZ_4G)); + min(search_end, search_low_max)); if (crash_base =3D=3D 0) { - /* Try again without restricting region to 32bit addressible memory */ + if (fixed_base) { + pr_warn("crashkernel: allocating failed with given size@offset\n"); + return; + } + + /* Try again above the region of 32bit addressible memory */ crash_base =3D memblock_phys_alloc_range(crash_size, PMD_SIZE, - search_start, search_end); + max(search_start, search_low_max), + search_end); if (crash_base =3D=3D 0) { pr_warn("crashkernel: couldn't allocate %lldKB\n", crash_size >> 10); return; } + + if (!crash_low_size) + crash_low_size =3D 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; } =20 pr_info("crashkernel: reserved 0x%016llx - 0x%016llx (%lld MB)\n", --=20 2.31.1