From nobody Tue Feb 10 17:08:08 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 5EA14C77B7F for ; Thu, 11 May 2023 08:51:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236267AbjEKIvr (ORCPT ); Thu, 11 May 2023 04:51:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233552AbjEKIvf (ORCPT ); Thu, 11 May 2023 04:51:35 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BEE15FF2; Thu, 11 May 2023 01:51:33 -0700 (PDT) Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4QH5CX6zpmzLnj1; Thu, 11 May 2023 16:48:40 +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; Thu, 11 May 2023 16:51:31 +0800 From: Chen Jiahao To: , , , CC: , , , , , , , , , , , Subject: [PATCH -next v5 1/2] riscv: kdump: Implement crashkernel=X,[high,low] Date: Thu, 11 May 2023 16:51:38 +0800 Message-ID: <20230511085139.1039088-2-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230511085139.1039088-1-chenjiahao16@huawei.com> References: <20230511085139.1039088-1-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 | 73 +++++++++++++++++++++++++++++++++++---- 2 files changed, 71 insertions(+), 7 deletions(-) diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 36b026057503..e0b7c1651d60 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 747e5b1ef02d..910d2e8c3c77 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -1272,6 +1272,28 @@ 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 * @@ -1283,8 +1305,11 @@ 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; =20 int ret =3D 0; =20 @@ -1300,14 +1325,34 @@ 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_end =3D memblock_end_of_DRAM(); + } 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; } @@ -1320,17 +1365,31 @@ 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 */ + if (fixed_base) { + pr_warn("crashkernel: allocating failed with given size@offset\n"); + return; + } + search_end =3D memblock_end_of_DRAM(); + + /* Try again above the region of 32bit addressible memory */ 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); 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 From nobody Tue Feb 10 17:08:08 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 E8D92C7EE25 for ; Thu, 11 May 2023 08:51:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235692AbjEKIvo (ORCPT ); Thu, 11 May 2023 04:51:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232114AbjEKIvf (ORCPT ); Thu, 11 May 2023 04:51:35 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AA305FD0; Thu, 11 May 2023 01:51:33 -0700 (PDT) Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4QH59y6TpwzpVCp; Thu, 11 May 2023 16:47:18 +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; Thu, 11 May 2023 16:51:31 +0800 From: Chen Jiahao To: , , , CC: , , , , , , , , , , , Subject: [PATCH -next v5 2/2] docs: kdump: Update the crashkernel description for riscv Date: Thu, 11 May 2023 16:51:39 +0800 Message-ID: <20230511085139.1039088-3-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230511085139.1039088-1-chenjiahao16@huawei.com> References: <20230511085139.1039088-1-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" Now "crashkernel=3D" parameter on riscv has been updated to support crashkernel=3DX,[high,low]. Through which we can reserve memory region above/within 32bit addressible DMA zone. Here update the parameter description accordingly. Signed-off-by: Chen Jiahao Reviewed-by: Guo Ren Reviewed-by: Simon Horman Reviewed-by: Zhen Lei --- Documentation/admin-guide/kernel-parameters.txt | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 9e5bab29685f..982da6bcaebd 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -866,7 +866,7 @@ memory region [offset, offset + size] for that kernel image. If '@offset' is omitted, then a suitable offset is selected automatically. - [KNL, X86-64, ARM64] Select a region under 4G first, and + [KNL, X86-64, ARM64, RISCV] Select a region under 4G first, and fall back to reserve region above 4G when '@offset' hasn't been specified. See Documentation/admin-guide/kdump/kdump.rst for further details. @@ -879,14 +879,14 @@ Documentation/admin-guide/kdump/kdump.rst for an example. =20 crashkernel=3Dsize[KMG],high - [KNL, X86-64, ARM64] range could be above 4G. Allow kernel - to allocate physical memory region from top, so could - be above 4G if system have more than 4G ram installed. - Otherwise memory region will be allocated below 4G, if - available. + [KNL, X86-64, ARM64, RISCV] range could be above 4G. + Allow kernel to allocate physical memory region from top, + so could be above 4G if system have more than 4G ram + installed. Otherwise memory region will be allocated + below 4G, if available. It will be ignored if crashkernel=3DX is specified. crashkernel=3Dsize[KMG],low - [KNL, X86-64, ARM64] range under 4G. When crashkernel=3DX,high + [KNL, X86-64, ARM64, RISCV] range under 4G. When crashkernel=3DX,high is passed, kernel could allocate physical memory region above 4G, that cause second kernel crash on system that require some amount of low memory, e.g. swiotlb @@ -897,6 +897,7 @@ size is platform dependent. --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB) --> arm64: 128MiB + --> riscv: 128MiB This one lets the user specify own low range under 4G for second kernel instead. 0: to disable low allocation. --=20 2.31.1