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 0684EC433F5 for ; Mon, 14 Feb 2022 07:29:21 +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=EQLJ72pHmOuLpwBJj/Yscl+6BruOpF2+l0pV9CeSsRM=; b=DZtKkoNuysj55l V2LTXskS0C4s7hSxFPkM3MiiKyMs/rotCX3Lh50SJeWNjk/XW/SLCy1C1SBF+P5udDep7wvosMEOh 9yP0bdtQCBKf4Zn4O8TC7KVIGxDir45LRRlNw5kAYg7MuxN9jklqkZCodY+AOzufzNdBe9poD0aLX yT6BUprudQjV5+MmV2mZ36GJEoFJrzAuP3OgueGAO/nsKsa+TOykjrc73g74KSrP09XjAR8Pfdjsr PgMEIq1ZBvmuz91uqGzLOG6X69QmyzmZncj4cEJ1QhJydX8GGEJ4xssRYxIg4dDt1XWtZMr23yPFB u0dk3GFGdQqsQ1DJiQtQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJVln-00DhQL-0u; Mon, 14 Feb 2022 07:27:36 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJVV0-00Db1I-LN for linux-arm-kernel@lists.infradead.org; Mon, 14 Feb 2022 07:10:18 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644822613; 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=Y5iYrmeqFTWTMK2U/eGmx/ua6zxpJzL0laPaQH0XD4c=; b=fYWJCicLOliVZOPOe7VPnmp1B7Ydl7Ra8Ar9CF3Qw7s0HvjWWbihswAZblH+qlhTbooZdb WeEZ5Xdul9JYJlgn02LdEnmEiPpzzKnZhOd9glibC5VwphaK8x4JXmBhzMY/LBH4cDosA9 HXYDxmcPY2Oe+PNkgRf7ha7Aox6ittA= 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-352-U84TX2mcNDagSzVBXsNdkg-1; Mon, 14 Feb 2022 02:10:08 -0500 X-MC-Unique: U84TX2mcNDagSzVBXsNdkg-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 7A253180833A; Mon, 14 Feb 2022 07:10:05 +0000 (UTC) Received: from localhost (ovpn-13-68.pek2.redhat.com [10.72.13.68]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AC4A2105C751; Mon, 14 Feb 2022 07:10:01 +0000 (UTC) Date: Mon, 14 Feb 2022 15:09:58 +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> <441c2917-bd86-da71-22d2-f526baf1457f@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <441c2917-bd86-da71-22d2-f526baf1457f@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-20220213_231014_861426_8C2DFF19 X-CRM114-Status: GOOD ( 34.49 ) 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 02/14/22 at 02:44pm, Leizhen (ThunderTown) wrote: > > > On 2022/2/11 18:51, Baoquan He wrote: > > 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" > > Yes, so maybe we should change the error code in __parse_crashkernel() > from "-EINVAL" to "-ENOENT" when the specified option does not exist. Good point. I also thought of this, it could be next step clean up. X86 code need this too. In crashkernel='messy code',high, it will fail to reserve. For consistency, we should fail crashkrenel='messy code',low too. > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index 256cf6db573cd09..395f4fac1773f28 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -243,9 +243,8 @@ static int __init __parse_crashkernel(char *cmdline, > *crash_base = 0; > > ck_cmdline = get_last_crashkernel(cmdline, name, suffix); > - > if (!ck_cmdline) > - return -EINVAL; > + return -ENOENT; > > ck_cmdline += strlen(name); > > > > > >> > >>> > >>>> + > >>>> + 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 > >> > > > > . > > > > -- > Regards, > Zhen Lei > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel