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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0BE8CC433EF for ; Fri, 11 Feb 2022 11:00:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=s/solOfhD3NJsmu2ktwsYWYEEMM9JhvkhCX0QYZUmMM=; b=ZMj/L+fG/O8qmP MeELIgTR/Bzw1pgSZtkmiGGpXkR/DxOIKBCjbSoNAe+7VFZYNZtZQJX950wAvfC6wGQyzONI8SnmN GClGLoAOelQRTQTotHenjfELHaqnvnQxbT03q0bdGcpgaCc8Zjg2uFoSqLLVLdB47208S/Ta125v7 mNxq74VtGJg87ITM5cGcvT+NB30c3Ze912b2Qi68gaQsOi7PQN3tRLXxcmmP77a8xkzWOEnXAz9tc a39LDYWWIqJ/hv26amCfswWI28dz9EguukfhOwyXk9epTm/Oz/6BDXM1NDasl43NOGUO/ID4cEXAi aNXtyp/qHbJurgigOl/Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nITdl-006kn4-Ty; Fri, 11 Feb 2022 10:59:03 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nITWt-006hcj-4K for linux-arm-kernel@lists.infradead.org; Fri, 11 Feb 2022 10:51:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644576714; 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=T47+Rcwkbs9fTg1m8vFZfEqooU0yXJ4jVkI+Xz6QZGw=; b=ABCWIGMX/MVM4zs0JHF4IW0ciNm04M820pT4kEI0e6mUN0IryWzCgd71DQkAGTSWSaY8L/ iJHP16Helt2vZsEm/Bcg0PUD/3v6TEae4HkGlDSXb+0AuBH/9cLQqjRYQZeIi+PMcvfOBe 732rexC0Zr3BSfRleaYNXK/2CmLlHBM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-633-nNea0N0qMTWp2cD7rd-6Cg-1; Fri, 11 Feb 2022 05:51:50 -0500 X-MC-Unique: nNea0N0qMTWp2cD7rd-6Cg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8A9D939382; Fri, 11 Feb 2022 10:51:47 +0000 (UTC) Received: from localhost (ovpn-13-96.pek2.redhat.com [10.72.13.96]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D6D1510589C2; Fri, 11 Feb 2022 10:51:23 +0000 (UTC) Date: Fri, 11 Feb 2022 18:51:21 +0800 From: Baoquan He To: "Leizhen (ThunderTown)" Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , linux-kernel@vger.kernel.org, Dave Young , Vivek Goyal , Eric Biederman , kexec@lists.infradead.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Rob Herring , Frank Rowand , devicetree@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou , John Donnelly , Dave Kleikamp Subject: Re: [PATCH v20 3/5] arm64: kdump: reimplement crashkernel=X Message-ID: References: <20220124084708.683-1-thunder.leizhen@huawei.com> <20220124084708.683-4-thunder.leizhen@huawei.com> <6ac0c60c-78bc-9789-9f5c-659fb5fa3e9a@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <6ac0c60c-78bc-9789-9f5c-659fb5fa3e9a@huawei.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220211_025155_317681_52F87479 X-CRM114-Status: GOOD ( 31.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 02/11/22 at 06:41pm, Leizhen (ThunderTown) wrote: > > > On 2022/2/11 18:30, Baoquan He wrote: > > On 01/24/22 at 04:47pm, Zhen Lei wrote: > >> From: Chen Zhou > > ...... > >> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > >> index 6c653a2c7cff052..a5d43feac0d7d96 100644 > >> --- a/arch/arm64/mm/init.c > >> +++ b/arch/arm64/mm/init.c > >> @@ -71,6 +71,30 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init; > >> #define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit > >> #define CRASH_ADDR_HIGH_MAX MEMBLOCK_ALLOC_ACCESSIBLE > >> > >> +static int __init reserve_crashkernel_low(unsigned long long low_size) > >> +{ > >> + unsigned long long low_base; > >> + > >> + /* passed with crashkernel=0,low ? */ > >> + if (!low_size) > >> + return 0; > >> + > >> + low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX); > >> + 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%llx - 0x%llx (%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; > >> + insert_resource(&iomem_resource, &crashk_low_res); > >> + > >> + return 0; > >> +} > >> + > >> /* > >> * reserve_crashkernel() - reserves memory for crash kernel > >> * > >> @@ -81,29 +105,62 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init; > >> static void __init reserve_crashkernel(void) > >> { > >> unsigned long long crash_base, crash_size; > >> + unsigned long long crash_low_size = SZ_256M; > >> unsigned long long crash_max = CRASH_ADDR_LOW_MAX; > >> int ret; > >> + bool fixed_base; > >> + char *cmdline = boot_command_line; > >> > >> - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), > >> + /* crashkernel=X[@offset] */ > >> + ret = parse_crashkernel(cmdline, memblock_phys_mem_size(), > >> &crash_size, &crash_base); > >> - /* no crashkernel= or invalid value specified */ > >> - if (ret || !crash_size) > >> - return; > >> + if (ret || !crash_size) { > >> + unsigned long long low_size; > >> > >> + /* crashkernel=X,high */ > >> + ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base); > >> + if (ret || !crash_size) > >> + return; > >> + > >> + /* crashkernel=X,low */ > >> + ret = parse_crashkernel_low(cmdline, 0, &low_size, &crash_base); > >> + if (!ret) > >> + crash_low_size = low_size; > > > > Here, the error case is not checked and handled. But it still gets > > expeced result which is the default SZ_256M. Is this designed on > > purpose? > > Yes, we can specify only "crashkernel=X,high". > > This is mentioned in Documentation/admin-guide/kernel-parameters.txt > > crashkernel=size[KMG],low > [KNL, X86-64] range under 4G. When crashkernel=X,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 > requires at least 64M+32K low memory, also enough extra > low memory is needed to make sure DMA buffers for 32-bit > devices won't run out. Kernel would try to allocate at <--------- > least 256M below 4G automatically. <--------- Yeah, that is expected becasue no crahskernel=,low is a right usage. The 'ret' is 0 in the case. If I gave below string, it works too. "crashkernel=256M,high crashkernel=aaabbadfadfd,low" > > > > >> + > >> + crash_max = CRASH_ADDR_HIGH_MAX; > >> + } > >> + > >> + fixed_base = !!crash_base; > >> crash_size = PAGE_ALIGN(crash_size); > >> > >> /* User specifies base address explicitly. */ > >> if (crash_base) > >> crash_max = crash_base + crash_size; > >> > >> +retry: > >> crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, > >> crash_base, crash_max); > >> if (!crash_base) { > >> + /* > >> + * Attempt to fully allocate low memory failed, fall back > >> + * to high memory, the minimum required low memory will be > >> + * reserved later. > >> + */ > >> + if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) { > >> + crash_max = CRASH_ADDR_HIGH_MAX; > >> + goto retry; > >> + } > >> + > >> pr_warn("cannot allocate crashkernel (size:0x%llx)\n", > >> crash_size); > >> return; > >> } > >> > >> + if (crash_base >= SZ_4G && 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); > >> > >> @@ -112,6 +169,9 @@ static void __init reserve_crashkernel(void) > >> * map. Inform kmemleak so that it won't try to access it. > >> */ > >> kmemleak_ignore_phys(crash_base); > >> + if (crashk_low_res.end) > >> + kmemleak_ignore_phys(crashk_low_res.start); > >> + > >> crashk_res.start = crash_base; > >> crashk_res.end = crash_base + crash_size - 1; > >> insert_resource(&iomem_resource, &crashk_res); > >> -- > >> 2.25.1 > >> > > > > . > > > > -- > Regards, > Zhen Lei > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel