From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754610AbaHAIPd (ORCPT ); Fri, 1 Aug 2014 04:15:33 -0400 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:52446 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750851AbaHAIPa (ORCPT ); Fri, 1 Aug 2014 04:15:30 -0400 Message-ID: <53DB4C9A.8050400@linux.vnet.ibm.com> Date: Fri, 01 Aug 2014 13:45:22 +0530 From: Vasant Hegde User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Andrew Morton CC: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Linus Torvalds , Benjamin Herrenschmidt Subject: Re: [PATCH v2 1/2] printk: Add function to return log buffer address and size References: <20140731153447.27134.44225.stgit@hegdevasant.in.ibm.com> <20140731152255.37e675870dfdf77d9dbaff70@linux-foundation.org> In-Reply-To: <20140731152255.37e675870dfdf77d9dbaff70@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14080108-2000-0000-0000-000001590B6F Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/01/2014 03:52 AM, Andrew Morton wrote: > On Thu, 31 Jul 2014 21:05:48 +0530 Vasant Hegde wrote: > >> Platforms like IBM Power Systems supports service processor >> assisted dump. It provides interface to add memory region to >> be captured when system is crashed. >> >> During initialization/running we can add kernel memory region >> to be collected. >> >> Presently we don't have a way to get the log buffer base address >> and size. This patch adds support to return log buffer address >> and size. >> >> ... >> >> --- a/include/linux/printk.h >> +++ b/include/linux/printk.h >> @@ -10,6 +10,9 @@ >> extern const char linux_banner[]; >> extern const char linux_proc_banner[]; >> >> +extern void *get_log_buf_addr(void); >> +extern u32 get_log_buf_len(void); >> + >> static inline int printk_get_level(const char *buffer) >> { >> if (buffer[0] == KERN_SOH_ASCII && buffer[1]) { >> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c >> index 13e839d..4049f7b 100644 >> --- a/kernel/printk/printk.c >> +++ b/kernel/printk/printk.c >> @@ -270,6 +270,18 @@ static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); >> static char *log_buf = __log_buf; >> static u32 log_buf_len = __LOG_BUF_LEN; >> >> +/* Return log buffer address */ >> +void *get_log_buf_addr(void) >> +{ >> + return log_buf; >> +} >> + >> +/* Return log buffer size */ >> +u32 get_log_buf_len(void) >> +{ >> + return log_buf_len; >> +} >> + >> /* human readable text of the record */ >> static char *log_text(const struct printk_log *msg) >> { > Andrew, Thanks for the review.. Shall I add your Ack? > Looks OK to me, although I think log_buf_addr_get() and > log_buf_len_get() would be better names. The kernel uses some > big-endian names and some little-endian-names and some middle-endian > names. It's all rather a mess. These symbols are already big-endian > (ie: decreasing significance): > > log_buf -> addr -> get > log_buf -> len -> get Sure . Will rename function as above. > > > The world wouldn't end if we simply made log_buf and log_buf_len global > symbols. The pros and cons are all minor. > > It's probably better to make get_log_buf_addr() tell the truth and > return a char *. > > > Please include this in whatever tree carries "powerpc/powernv: > Interface to register/unregister opal dump region". Sure.. Will work with BenH. -Vasant