From patchwork Tue Jun 25 03:17:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alastair D'Silva X-Patchwork-Id: 11014551 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D5E3713AF for ; Tue, 25 Jun 2019 03:20:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C73EA1FE8E for ; Tue, 25 Jun 2019 03:20:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BAEB7200DF; Tue, 25 Jun 2019 03:20:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 27C201FE8E for ; Tue, 25 Jun 2019 03:20:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728706AbfFYDTg (ORCPT ); Mon, 24 Jun 2019 23:19:36 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:19772 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727998AbfFYDTf (ORCPT ); Mon, 24 Jun 2019 23:19:35 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5P36gZG122197 for ; Mon, 24 Jun 2019 23:19:34 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tb9sabrmr-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 24 Jun 2019 23:19:33 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 25 Jun 2019 04:19:22 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5P3JLgJ49283266 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 Jun 2019 03:19:21 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1A2BEA404D; Tue, 25 Jun 2019 03:19:21 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7725CA4040; Tue, 25 Jun 2019 03:19:20 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 25 Jun 2019 03:19:20 +0000 (GMT) Received: from adsilva.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 4705BA02A1; Tue, 25 Jun 2019 13:19:19 +1000 (AEST) From: "Alastair D'Silva" To: alastair@d-silva.org Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , Dan Carpenter , Karsten Keil , Jassi Brar , Tom Lendacky , "David S. Miller" , Jose Abreu , Kalle Valo , Stanislaw Gruszka , Benson Leung , Enric Balletbo i Serra , "James E.J. Bottomley" , "Martin K. Petersen" , Greg Kroah-Hartman , Alexander Viro , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , David Laight , Andrew Morton , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fbdev@vger.kernel.org, devel@driverdev.osuosl.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v4 3/7] lib/hexdump.c: Optionally suppress lines of repeated bytes Date: Tue, 25 Jun 2019 13:17:22 +1000 X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190625031726.12173-1-alastair@au1.ibm.com> References: <20190625031726.12173-1-alastair@au1.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 19062503-0016-0000-0000-0000028C0D9A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19062503-0017-0000-0000-000032E97D2F Message-Id: <20190625031726.12173-4-alastair@au1.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-25_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906250024 Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Alastair D'Silva Some buffers may only be partially filled with useful data, while the rest is padded (typically with 0x00 or 0xff). This patch introduces a flag to allow the supression of lines of repeated bytes, which are replaced with '** Skipped %u bytes of value 0x%x **' An inline wrapper function is provided for backwards compatibility with existing code, which maintains the original behaviour. Signed-off-by: Alastair D'Silva --- include/linux/printk.h | 26 +++++++++--- lib/hexdump.c | 91 ++++++++++++++++++++++++++++++++++++------ 2 files changed, 100 insertions(+), 17 deletions(-) diff --git a/include/linux/printk.h b/include/linux/printk.h index cefd374c47b1..c0416d0eb9e2 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -7,6 +7,7 @@ #include #include #include +#include extern const char linux_banner[]; extern const char linux_proc_banner[]; @@ -481,13 +482,18 @@ enum { DUMP_PREFIX_ADDRESS, DUMP_PREFIX_OFFSET }; + extern int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize, char *linebuf, size_t linebuflen, bool ascii); + +#define HEXDUMP_ASCII BIT(0) +#define HEXDUMP_SUPPRESS_REPEATED BIT(1) + #ifdef CONFIG_PRINTK -extern void print_hex_dump(const char *level, const char *prefix_str, +extern void print_hex_dump_ext(const char *level, const char *prefix_str, int prefix_type, int rowsize, int groupsize, - const void *buf, size_t len, bool ascii); + const void *buf, size_t len, u32 flags); #if defined(CONFIG_DYNAMIC_DEBUG) #define print_hex_dump_bytes(prefix_str, prefix_type, buf, len) \ dynamic_hex_dump(prefix_str, prefix_type, 16, 1, buf, len, true) @@ -496,18 +502,28 @@ extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type, const void *buf, size_t len); #endif /* defined(CONFIG_DYNAMIC_DEBUG) */ #else -static inline void print_hex_dump(const char *level, const char *prefix_str, +static inline void print_hex_dump_ext(const char *level, const char *prefix_str, int prefix_type, int rowsize, int groupsize, - const void *buf, size_t len, bool ascii) + const void *buf, size_t len, u32 flags) { } static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type, const void *buf, size_t len) { } - #endif +static __always_inline void print_hex_dump(const char *level, + const char *prefix_str, + int prefix_type, int rowsize, + int groupsize, const void *buf, + size_t len, bool ascii) +{ + print_hex_dump_ext(level, prefix_str, prefix_type, rowsize, groupsize, + buf, len, ascii ? HEXDUMP_ASCII : 0); +} + + #if defined(CONFIG_DYNAMIC_DEBUG) #define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \ groupsize, buf, len, ascii) \ diff --git a/lib/hexdump.c b/lib/hexdump.c index 870c8cbff1e1..61dc625c32f5 100644 --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -212,8 +212,44 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize, EXPORT_SYMBOL(hex_dump_to_buffer); #ifdef CONFIG_PRINTK + +/** + * buf_is_all - Check if a buffer contains only a single byte value + * @buf: pointer to the buffer + * @len: the size of the buffer in bytes + * @val: outputs the value if if the bytes are identical + */ +static bool buf_is_all(const u8 *buf, size_t len, u8 *val_out) +{ + size_t i; + u8 val; + + if (len <= 1) + return false; + + val = buf[0]; + + for (i = 1; i < len; i++) { + if (buf[i] != val) + return false; + } + + *val_out = val; + return true; +} + +static void announce_skipped(const char *level, const char *prefix_str, + u8 val, size_t count) +{ + if (count == 0) + return; + + printk("%s%s ** Skipped %lu bytes of value 0x%x **\n", + level, prefix_str, count, val); +} + /** - * print_hex_dump - print a text hex dump to syslog for a binary blob of data + * print_hex_dump_ext - dump a binary blob of data to syslog in hexadecimal * @level: kernel log level (e.g. KERN_DEBUG) * @prefix_str: string to prefix each line with; * caller supplies trailing spaces for alignment if desired @@ -224,6 +260,10 @@ EXPORT_SYMBOL(hex_dump_to_buffer); * @buf: data blob to dump * @len: number of bytes in the @buf * @ascii: include ASCII after the hex output + * @flags: A bitwise OR of the following flags: + * HEXDUMP_ASCII: include ASCII after the hex output + * HEXDUMP_SUPPRESS_REPEATED: suppress repeated lines of identical + * bytes * * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump * to the kernel log at the specified kernel log level, with an optional @@ -234,22 +274,25 @@ EXPORT_SYMBOL(hex_dump_to_buffer); * (optionally) ASCII output. * * E.g.: - * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS, - * 16, 1, frame->data, frame->len, true); + * print_hex_dump_ext(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS, + * 16, 1, frame->data, frame->len, HEXDUMP_ASCII); * * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode: * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode: * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~. */ -void print_hex_dump(const char *level, const char *prefix_str, int prefix_type, - int rowsize, int groupsize, - const void *buf, size_t len, bool ascii) +void print_hex_dump_ext(const char *level, const char *prefix_str, + int prefix_type, int rowsize, int groupsize, + const void *buf, size_t len, u32 flags) { const u8 *ptr = buf; - int i, linelen, remaining = len; + int i, remaining = len; unsigned char *linebuf; unsigned int linebuf_len; + u8 skipped_val = 0; + size_t skipped = 0; + if (rowsize % groupsize) rowsize -= rowsize % groupsize; @@ -267,11 +310,35 @@ void print_hex_dump(const char *level, const char *prefix_str, int prefix_type, } for (i = 0; i < len; i += rowsize) { - linelen = min(remaining, rowsize); + int linelen = min(remaining, rowsize); remaining -= rowsize; + if (flags & HEXDUMP_SUPPRESS_REPEATED) { + u8 new_val; + + if (buf_is_all(ptr + i, linelen, &new_val)) { + if (new_val == skipped_val) { + skipped += linelen; + continue; + } else { + announce_skipped(level, prefix_str, + skipped_val, skipped); + skipped_val = new_val; + skipped = linelen; + continue; + } + } + } + + if (skipped) { + announce_skipped(level, prefix_str, skipped_val, + skipped); + skipped = 0; + } + hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize, - linebuf, linebuf_len, ascii); + linebuf, linebuf_len, + flags & HEXDUMP_ASCII); switch (prefix_type) { case DUMP_PREFIX_ADDRESS: @@ -289,7 +356,7 @@ void print_hex_dump(const char *level, const char *prefix_str, int prefix_type, kfree(linebuf); } -EXPORT_SYMBOL(print_hex_dump); +EXPORT_SYMBOL(print_hex_dump_ext); #if !defined(CONFIG_DYNAMIC_DEBUG) /** @@ -307,8 +374,8 @@ EXPORT_SYMBOL(print_hex_dump); void print_hex_dump_bytes(const char *prefix_str, int prefix_type, const void *buf, size_t len) { - print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1, - buf, len, true); + print_hex_dump_ext(KERN_DEBUG, prefix_str, prefix_type, 16, 1, + buf, len, HEXDUMP_ASCII); } EXPORT_SYMBOL(print_hex_dump_bytes); #endif /* !defined(CONFIG_DYNAMIC_DEBUG) */