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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A5A0C43331 for ; Mon, 11 Nov 2019 18:14:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 16B04206C3 for ; Mon, 11 Nov 2019 18:14:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726951AbfKKSOo (ORCPT ); Mon, 11 Nov 2019 13:14:44 -0500 Received: from ale.deltatee.com ([207.54.116.67]:42876 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726763AbfKKSOn (ORCPT ); Mon, 11 Nov 2019 13:14:43 -0500 Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.89) (envelope-from ) id 1iUECv-00018v-1q; Mon, 11 Nov 2019 11:14:33 -0700 To: Yash Shah , "Paul Walmsley ( Sifive)" , "linux-riscv@lists.infradead.org" , "linux-kernel@vger.kernel.org" Cc: "palmer@dabbelt.com" , "aou@eecs.berkeley.edu" , "Anup.Patel@wdc.com" , "rppt@linux.ibm.com" , "ren_guo@c-sky.com" , "bmeng.cn@gmail.com" , "tglx@linutronix.de" , Sachin Ghadi References: <1573450015-16475-1-git-send-email-yash.shah@sifive.com> From: Logan Gunthorpe Message-ID: <91f35033-ffc8-cd2e-36f7-c6f4f25be36b@deltatee.com> Date: Mon, 11 Nov 2019 11:14:30 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <1573450015-16475-1-git-send-email-yash.shah@sifive.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: sachin.ghadi@sifive.com, tglx@linutronix.de, bmeng.cn@gmail.com, ren_guo@c-sky.com, rppt@linux.ibm.com, Anup.Patel@wdc.com, aou@eecs.berkeley.edu, palmer@dabbelt.com, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, paul.walmsley@sifive.com, yash.shah@sifive.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH] RISC-V: Add address map dumper X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-11-10 10:27 p.m., Yash Shah wrote: > Add support for dumping the kernel address space layout to the console. > User can enable CONFIG_DEBUG_VM_LAYOUT to dump the virtual memory region > into dmesg buffer during boot-up. Cool, I'd find this useful. Though, is there any reason we don't do this more generally for all architectures? > Signed-off-by: Yash Shah > --- > This patch is based on Linux 5.4-rc6 and tested on SiFive HiFive Unleashed > board. > --- > arch/riscv/Kconfig.debug | 9 +++++++++ > arch/riscv/mm/init.c | 30 ++++++++++++++++++++++++++++++ > 2 files changed, 39 insertions(+) > > diff --git a/arch/riscv/Kconfig.debug b/arch/riscv/Kconfig.debug > index e69de29..cdedfd3 100644 > --- a/arch/riscv/Kconfig.debug > +++ b/arch/riscv/Kconfig.debug > @@ -0,0 +1,9 @@ > +config DEBUG_VM_LAYOUT > + bool "Print virtual memory layout on boot up" > + depends on DEBUG_KERNEL > + help > + Say Y here if you want to dump the kernel virtual memory layout to > + dmesg log on boot up. This information is only useful for kernel > + developers who are working in architecture specific areas of the > + kernel. It is probably not a good idea to enable this feature in a > + production kernel. > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 79cfb35..fcb8144 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -55,6 +55,36 @@ void __init mem_init(void) > memblock_free_all(); > > mem_init_print_info(NULL); > +#ifdef CONFIG_DEBUG_VM_LAYOUT Generally, it's best to avoid #ifdefs inside functions, it's even counter-indicated in the style guide[1]. > +#define MLK(b, t) b, t, (((t) - (b)) >> 10) > +#define MLM(b, t) b, t, (((t) - (b)) >> 20) > +#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K) I personally find these inline defines rather ugly. Maybe it would be better to have a helper function that prints a single line. Also seems like MLK and MLK_ROUNDUP could be the same assuming the entries in MLK are aligned... > + > + pr_notice("Virtual kernel memory layout:\n" > + " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" > + " vmemmap : 0x%08lx - 0x%08lx (%4ld MB)\n" > + " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" > + " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" > + " .init : 0x%px - 0x%px (%4td kB)\n" > + " .text : 0x%px - 0x%px (%4td kB)\n" > + " .data : 0x%px - 0x%px (%4td kB)\n" > + " .bss : 0x%px - 0x%px (%4td kB)\n", > + > + MLK(FIXADDR_START, FIXADDR_TOP), > + MLM(VMEMMAP_START, VMEMMAP_END), > + MLM(VMALLOC_START, VMALLOC_END), > + MLM(PAGE_OFFSET, (unsigned long)high_memory), > + > + MLK_ROUNDUP(__init_begin, __init_end), > + MLK_ROUNDUP(_text, _etext), > + MLK_ROUNDUP(_sdata, _edata), > + MLK_ROUNDUP(__bss_start, __bss_stop)); > + > +#undef MLK > +#undef MLM > +#undef MLK_ROUNDUP > +#endif > } > > #ifdef CONFIG_BLK_DEV_INITRD Thanks, Logan [1] https://www.kernel.org/doc/html/latest/process/coding-style.html#conditional-compilation