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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2349DFA3740 for ; Mon, 31 Oct 2022 08:59:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229641AbiJaI7I (ORCPT ); Mon, 31 Oct 2022 04:59:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230020AbiJaI7A (ORCPT ); Mon, 31 Oct 2022 04:59:00 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCDB51D3 for ; Mon, 31 Oct 2022 01:58:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667206681; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z91eHH8pl3kslsZiDOnRRDgLPUm79K5+l5tngN5wAPg=; b=FFz5deb6V7FsAWGsUjvZ81nW5W6yGz3Zrsa7LSB8gdeq5B2Dz/Mp4spcEhC7vppdC9RY6a vVd4yxWEInGVabqiv3azaIw5x9Usup8jIHLQeLZ1kPUI3W8f0fApnudWs71G71v3iE7kJ1 URsdgmT/O9VFuX6IqTFH6BP7iaGQhIU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-422-5cSb-gPSOlGPn2x72M2L9Q-1; Mon, 31 Oct 2022 04:57:53 -0400 X-MC-Unique: 5cSb-gPSOlGPn2x72M2L9Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D38751012466; Mon, 31 Oct 2022 08:57:52 +0000 (UTC) Received: from localhost (ovpn-12-152.pek2.redhat.com [10.72.12.152]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 85CCB40C2066; Mon, 31 Oct 2022 08:57:50 +0000 (UTC) Date: Mon, 31 Oct 2022 16:57:47 +0800 From: Baoquan He To: Conor Dooley Cc: Xianting Tian , Conor Dooley , Palmer Dabbelt , paul.walmsley@sifive.com, aou@eecs.berkeley.edu, anup@brainfault.org, heiko@sntech.de, guoren@kernel.org, mick@ics.forth.gr, alexandre.ghiti@canonical.com, vgoyal@redhat.com, dyoung@redhat.com, corbet@lwn.net, bagasdotme@gmail.com, k-hagio-ab@nec.com, lijiang@redhat.com, kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, crash-utility@redhat.com, heinrich.schuchardt@canonical.com, hschauhan@nulltrace.org, yixun.lan@gmail.com Subject: Re: [PATCH V4 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support Message-ID: References: <20221019103623.7008-2-xianting.tian@linux.alibaba.com> <30621b3b-47ba-d612-cfb0-583d779691a3@linux.alibaba.com> <6af05838-fa58-8197-f3ce-ca95457077a7@linux.alibaba.com> <5df30e57-88ae-0a3b-2c1a-b962363d8670@linux.alibaba.com> <3c8beab1-3ca7-c3d7-6f31-c28a0ae008a3@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 10/26/22 at 02:47pm, Conor Dooley wrote: > On Wed, Oct 26, 2022 at 08:05:41PM +0800, Baoquan He wrote: > > Hi Xianting, > > > > On 10/26/22 at 05:44pm, Xianting Tian wrote: > > > > > > 在 2022/10/26 下午5:25, Conor Dooley 写道: > > > > On Wed, Oct 26, 2022 at 05:08:11PM +0800, Xianting Tian wrote: > > > > > Hi Palmer, Conor > > > > > > > > > > Is this version OK for you? > > > > The weird ifdef/IS_ENABLED thing was the only comment I had. It's a bit > > > > odd & I notice Baoquan brought it up too. I didn't (and won't) give you > > > > a reviewed by on these patches because I don't understand the area well > > > > enough. The general nitpickery seems to be sorted though. > > > > > > I checked the KERNEL_LINK_ADDR definition of riscv,  it is valid for > > > CONFIG_64BIT and !CONFIG_64BIT. > > > > This series looks good to me. My only minor concern is if we can make > > the arch_crash_save_vmcoreinfo() as below. I don't understand why we > > have to have the CONFIG_64BIT ifdeffery and the IS_ENABLED(CONFIG_64BIT) > > between two adjacent code blocks. Not sure if we are saying the same > > thing. > > I think we can just go and drop the IS_ENABLED(). From looking at it > last time, one bit is compileable (but not usable) for !64BIT and the > other isn't hence the IS_ENABLED(). I think it would make sense to drop > the IS_ENABLED() - I don't think we're too likely to hit some compile > testing edge cases that IS_ENABLED() would help with & only having one > makes the code look a lot less odd and a lot more intentional. I check risc-v code again, and agree we can drop the IS_ENABLED checking to export KERNEL_LINK_ADDR anyway. We can surely deduce KERNEL_LINK_ADDR in userspace e.g makedumpfile/Crash, while it seems no harm to get it from the vmcoreinfo directly. As for the difference between "#ifdef CONFIG_64BIT" and "if (IS_ENABLED(CONFIG_64BIT))", I haven't got what's the Xianting's point. Below is the IS_ENABLED definition in include/linux/kconfig.h, it's truly different than #ifdef, while the change we are discussing here is not related. /* * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm', * 0 otherwise. Note that CONFIG_FOO=y results in "#define CONFIG_FOO 1" in * autoconf.h, while CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1". */ #define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option)) > > > > > +void arch_crash_save_vmcoreinfo(void) > > +{ > > + VMCOREINFO_NUMBER(VA_BITS); > > + VMCOREINFO_NUMBER(phys_ram_base); > > + > > + vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", PAGE_OFFSET); > > + vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START); > > + vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END); > > + vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", VMEMMAP_START); > > + vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END); > > +#ifdef CONFIG_64BIT > > + vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR); > > + vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END); > > + vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR); > > +#endif > > +} > > > > > > > > Maybe we can remove IS_ENABLED(CONFIG_64BIT) > > > > > > arch/riscv/include/asm/pgtable.h > > > #define ADDRESS_SPACE_END       (UL(-1)) > > > #ifdef CONFIG_64BIT > > > /* Leave 2GB for kernel and BPF at the end of the address space */ > > > #define KERNEL_LINK_ADDR        (ADDRESS_SPACE_END - SZ_2G + 1) > > > #else > > > #define KERNEL_LINK_ADDR        PAGE_OFFSET > > > #endif > > > > > > arch/riscv/include/asm/page.h > > > #ifdef CONFIG_64BIT > > > #ifdef CONFIG_MMU > > > #define PAGE_OFFSET             kernel_map.page_offset > > > #else > > > #define PAGE_OFFSET             _AC(CONFIG_PAGE_OFFSET, UL) > > > #endif > > > /* > > >  * By default, CONFIG_PAGE_OFFSET value corresponds to SV48 address space so > > >  * define the PAGE_OFFSET value for SV39. > > >  */ > > > #define PAGE_OFFSET_L4          _AC(0xffffaf8000000000, UL) > > > #define PAGE_OFFSET_L3          _AC(0xffffffd800000000, UL) > > > #else > > > #define PAGE_OFFSET             _AC(CONFIG_PAGE_OFFSET, UL) > > > #endif /* CONFIG_64BIT */ > > > > > > > > > > > Thanks, > > > > Conor. > > > > > > > > > 在 2022/10/20 下午12:40, Xianting Tian 写道: > > > > > > 在 2022/10/20 上午11:05, Baoquan He 写道: > > > > > > > On 10/20/22 at 10:17am, Xianting Tian wrote: > > > > > > > > 在 2022/10/20 上午10:08, Baoquan He 写道: > > > > > > > > > On 10/19/22 at 06:36pm, Xianting Tian wrote: > > > > > > > > > > Add arch_crash_save_vmcoreinfo(), which exports VM > > > > > > > > > > layout(MODULES, VMALLOC, > > > > > > > > > > VMEMMAP ranges and KERNEL_LINK_ADDR), va bits and ram > > > > > > > > > > base for vmcore. > > > > > > > > > > > > > > > > > > > > Default pagetable levels and PAGE_OFFSET aren't same for > > > > > > > > > > different kernel > > > > > > > > > > version as below. For pagetable levels, it sets sv57 by > > > > > > > > > > default and falls > > > > > > > > > > back to setting sv48 at boot time if sv57 is not > > > > > > > > > > supported by the hardware. > > > > > > > > > > > > > > > > > > > > For ram base, the default value is 0x80200000 for qemu > > > > > > > > > > riscv64 env and, > > > > > > > > > > for example, is 0x200000 on the XuanTie 910 CPU. > > > > > > > > > > > > > > > > > > > >    * Linux Kernel 5.18 ~ > > > > > > > > > >    *      PGTABLE_LEVELS = 5 > > > > > > > > > >    *      PAGE_OFFSET = 0xff60000000000000 > > > > > > > > > >    * Linux Kernel 5.17 ~ > > > > > > > > > >    *      PGTABLE_LEVELS = 4 > > > > > > > > > >    *      PAGE_OFFSET = 0xffffaf8000000000 > > > > > > > > > >    * Linux Kernel 4.19 ~ > > > > > > > > > >    *      PGTABLE_LEVELS = 3 > > > > > > > > > >    *      PAGE_OFFSET = 0xffffffe000000000 > > > > > > > > > > > > > > > > > > > > Since these configurations change from time to time and > > > > > > > > > > version to version, > > > > > > > > > > it is preferable to export them via vmcoreinfo than to > > > > > > > > > > change the crash's > > > > > > > > > > code frequently, it can simplify the development of crash tool. > > > > > > > > > > > > > > > > > > > > Signed-off-by: Xianting Tian > > > > > > > > > > --- > > > > > > > > > >    arch/riscv/kernel/Makefile     |  1 + > > > > > > > > > >    arch/riscv/kernel/crash_core.c | 23 +++++++++++++++++++++++ > > > > > > > > > >    2 files changed, 24 insertions(+) > > > > > > > > > >    create mode 100644 arch/riscv/kernel/crash_core.c > > > > > > > > > > > > > > > > > > > > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile > > > > > > > > > > index db6e4b1294ba..4cf303a779ab 100644 > > > > > > > > > > --- a/arch/riscv/kernel/Makefile > > > > > > > > > > +++ b/arch/riscv/kernel/Makefile > > > > > > > > > > @@ -81,6 +81,7 @@ obj-$(CONFIG_KGDB)        += kgdb.o > > > > > > > > > >    obj-$(CONFIG_KEXEC_CORE)    += kexec_relocate.o > > > > > > > > > > crash_save_regs.o machine_kexec.o > > > > > > > > > >    obj-$(CONFIG_KEXEC_FILE)    += elf_kexec.o machine_kexec_file.o > > > > > > > > > >    obj-$(CONFIG_CRASH_DUMP)    += crash_dump.o > > > > > > > > > > +obj-$(CONFIG_CRASH_CORE)    += crash_core.o > > > > > > > > > >    obj-$(CONFIG_JUMP_LABEL)    += jump_label.o > > > > > > > > > > diff --git a/arch/riscv/kernel/crash_core.c > > > > > > > > > > b/arch/riscv/kernel/crash_core.c > > > > > > > > > > new file mode 100644 > > > > > > > > > > index 000000000000..3e889d0ed7bd > > > > > > > > > > --- /dev/null > > > > > > > > > > +++ b/arch/riscv/kernel/crash_core.c > > > > > > > > > > @@ -0,0 +1,23 @@ > > > > > > > > > > +// SPDX-License-Identifier: GPL-2.0-only > > > > > > > > > > + > > > > > > > > > > +#include > > > > > > > > > > +#include > > > > > > > > > > + > > > > > > > > > > +void arch_crash_save_vmcoreinfo(void) > > > > > > > > > > +{ > > > > > > > > > > +    VMCOREINFO_NUMBER(VA_BITS); > > > > > > > > > > +    VMCOREINFO_NUMBER(phys_ram_base); > > > > > > > > > > + > > > > > > > > > > + > > > > > > > > > > vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", > > > > > > > > > > PAGE_OFFSET); > > > > > > > > > > + vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", > > > > > > > > > > VMALLOC_START); > > > > > > > > > > + > > > > > > > > > > vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", > > > > > > > > > > VMALLOC_END); > > > > > > > > > > + vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", > > > > > > > > > > VMEMMAP_START); > > > > > > > > > > + > > > > > > > > > > vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", > > > > > > > > > > VMEMMAP_END); > > > > > > > > > > +#ifdef CONFIG_64BIT > > > > > > > > > > + vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", > > > > > > > > > > MODULES_VADDR); > > > > > > > > > > + > > > > > > > > > > vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", > > > > > > > > > > MODULES_END); > > > > > > > > > > +#endif > > > > > > > > > > + > > > > > > > > > > +    if (IS_ENABLED(CONFIG_64BIT)) > > > > > > > > > > + > > > > > > > > > > vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", > > > > > > > > > > KERNEL_LINK_ADDR); > > > > > > > > > Wondering why you don't put KERNEL_LINK_ADDR exporting into the above > > > > > > > > > ifdeffery scope, with that you can save one line of > > > > > > > > > "IS_ENABLED(CONFIG_64BIT)". > > > > > > > > I followed the rule in print_vm_layout() of > > > > > > > > arch/riscv/mm/init.c, which used > > > > > > > > IS_ENABLED when print the value of KERNEL_LINK_ADDR. > > > > > > > > > > > > > > > I see. There's PAGE_OFFSET in the middle. Thanks. > > > > > > > > > > > > > >          print_ml("lowmem", (unsigned long)PAGE_OFFSET, > > > > > > >                  (unsigned long)high_memory) > > > > > > > > > > > > > > So now, do you think if it's necessary to have another > > > > > > > IS_ENABLED(CONFIG_64BIT) in the current arch_crash_save_vmcoreinfo()? > > > > > > For which MACRO?  I think current code for PAGE_OFFSET is OK. > > > > > > > > > > > >