From nobody Mon Feb 9 12:24:34 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 BFBEAC0015E for ; Wed, 26 Jul 2023 09:52:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233791AbjGZJv7 (ORCPT ); Wed, 26 Jul 2023 05:51:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233730AbjGZJvW (ORCPT ); Wed, 26 Jul 2023 05:51:22 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C016D2D5D; Wed, 26 Jul 2023 02:51:00 -0700 (PDT) Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4R9pwc1TSzztRjQ; Wed, 26 Jul 2023 17:47:44 +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 15.1.2507.27; Wed, 26 Jul 2023 17:50:58 +0800 From: Chen Jiahao To: , , , , , , , , , , , , , , , CC: Subject: [PATCH -next v9 1/2] riscv: kdump: Implement crashkernel=X,[high,low] Date: Wed, 26 Jul 2023 17:49:59 +0000 Message-ID: <20230726175000.2536220-2-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230726175000.2536220-1-chenjiahao16@huawei.com> References: <20230726175000.2536220-1-chenjiahao16@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.67.174.205] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) 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 Acked-by: Baoquan He --- 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 !=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 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 */ =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 * @@ -1308,8 +1330,12 @@ 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_end =3D (unsigned long)dma32_phys_limit; + char *cmdline =3D boot_command_line; + bool fixed_base =3D false; + bool high =3D false; =20 int ret =3D 0; =20 @@ -1325,14 +1351,36 @@ 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 (unsigned long)dma32_phys_limit; + search_end =3D memblock_end_of_DRAM(); + high =3D true; + } 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; } @@ -1345,12 +1393,37 @@ static void __init reserve_crashkernel(void) * swiotlb can work on the crash kernel. */ crash_base =3D memblock_phys_alloc_range(crash_size, PMD_SIZE, - search_start, - min(search_end, (unsigned long) SZ_4G)); + search_start, search_end); if (crash_base =3D=3D 0) { - /* Try again without restricting region to 32bit addressible memory */ + /* + * For crashkernel=3Dsize[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=3Dsize[KMG],high, if the first attempt was + * for high memory, fall back to low memory. + */ + search_start =3D memblock_start_of_DRAM(); + search_end =3D (unsigned long)dma32_phys_limit; + } else { + /* + * For crashkernel=3Dsize[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 =3D (unsigned long)dma32_phys_limit; + search_end =3D memblock_end_of_DRAM(); + crash_low_size =3D DEFAULT_CRASH_KERNEL_LOW_SIZE; + } + crash_base =3D memblock_phys_alloc_range(crash_size, PMD_SIZE, - search_start, search_end); + search_start, search_end); if (crash_base =3D=3D 0) { pr_warn("crashkernel: couldn't allocate %lldKB\n", crash_size >> 10); @@ -1358,6 +1431,12 @@ static void __init reserve_crashkernel(void) } } =20 + if ((crash_base >=3D 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); =20 --=20 2.34.1