From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp04.in.ibm.com (e28smtp04.in.ibm.com [122.248.162.4]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 7A06A1A0805 for ; Fri, 1 Aug 2014 18:15:35 +1000 (EST) Received: from /spool/local by e28smtp04.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 1 Aug 2014 13:45:29 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 1BFDAE001A for ; Fri, 1 Aug 2014 13:47:14 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s718FECA6160580 for ; Fri, 1 Aug 2014 13:45:15 +0530 Received: from d28av04.in.ibm.com (localhost [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s718FNYK028043 for ; Fri, 1 Aug 2014 13:45:23 +0530 Message-ID: <53DB4C9A.8050400@linux.vnet.ibm.com> Date: Fri, 01 Aug 2014 13:45:22 +0530 From: Vasant Hegde MIME-Version: 1.0 To: Andrew Morton 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 Cc: Linus Torvalds , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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