From patchwork Thu Oct 15 14:10:57 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Kagstrom X-Patchwork-Id: 36114 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id E27E5B7B76 for ; Fri, 16 Oct 2009 01:15:29 +1100 (EST) Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.69 #1 (Red Hat Linux)) id 1MyR32-0001qs-0U; Thu, 15 Oct 2009 14:11:20 +0000 Received: from ernst.netinsight.se ([194.16.221.21]) by bombadil.infradead.org with smtp (Exim 4.69 #1 (Red Hat Linux)) id 1MyR2v-0001pH-Kv for linux-mtd@lists.infradead.org; Thu, 15 Oct 2009 14:11:18 +0000 Received: from marrow.netinsight.se (unverified [10.100.3.78]) by ernst.netinsight.se (EMWAC SMTPRS 0.83) with SMTP id ; Thu, 15 Oct 2009 16:10:54 +0200 Date: Thu, 15 Oct 2009 16:10:57 +0200 From: Simon Kagstrom To: Simon Kagstrom Subject: [PATCH v8 5/5]: mtdoops: refactor as a kmsg_dumper Message-ID: <20091015161057.5b8ec8d8@marrow.netinsight.se> In-Reply-To: <20091015094815.36f5872c@marrow.netinsight.se> References: <20091015094057.7298e0d7@marrow.netinsight.se> <20091015094815.36f5872c@marrow.netinsight.se> X-Mailer: Claws Mail 3.7.3 (GTK+ 2.16.1; i486-pc-linux-gnu) Mime-Version: 1.0 X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20091015_101113_991588_09725CF6 X-CRM114-Status: GOOD ( 53.46 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.2.5 on bombadil.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- _SUMMARY_ Cc: David Woodhouse , linux-mtd , Artem Bityutskiy X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org The last messages which happens before a crash might contain interesting information about the crash. This patch reworks mtdoops using the kmsg_dumper support instead of a console, which simplifies the code and also includes the messages before the oops started. On oops callbacks, the MTD device write is scheduled in a work queue (to be able to use the regular mtd->write call), while panics call mtd->panic_write directly. Thus, if panic_on_oops is set, the oops will be written out during the panic. A parameter to specify which mtd device to use (number or name), as well as a flag, writable at runtime, to toggle wheter to dump oopses or only panics (since oopses can often be handled by regular syslog). Signed-off-by: Simon Kagstrom Reviewed-by: Anders Grafstrom --- ChangeLog: * Refactor against new version of patch 4 drivers/mtd/Kconfig | 5 +- drivers/mtd/mtdoops.c | 211 ++++++++++++++++++++----------------------------- 2 files changed, 88 insertions(+), 128 deletions(-) diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig index ecf90f5..60d6c31 100644 --- a/drivers/mtd/Kconfig +++ b/drivers/mtd/Kconfig @@ -312,8 +312,9 @@ config MTD_OOPS buffer in a flash partition where it can be read back at some later point. - To use, add console=ttyMTDx to the kernel command line, - where x is the MTD device number to use. + To use, add mtddev=name/number to the kernel command line, + where name/number is the name or number of the MTD device + to use (e.g., mtddev=7 for /dev/mtd7). source "drivers/mtd/chips/Kconfig" diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 2870a11..3af1016 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -29,18 +29,31 @@ #include #include #include -#include #include #include +#include #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00 +#define MTDOOPS_HEADER_SIZE 8 static unsigned long record_size = 4096; module_param(record_size, ulong, 0400); MODULE_PARM_DESC(record_size, "record size for MTD OOPS pages in bytes (default 4096)"); +static char mtddev[80]; +module_param_string(mtddev, mtddev, 80, 0400); +MODULE_PARM_DESC(mtddev, + "name or index number of the MTD device to use"); + +static int dump_oops = 1; +module_param(dump_oops, int, 0600); +MODULE_PARM_DESC(dump_oops, + "set to 1 to dump oopses, 0 to only dump panics (default 1)"); + static struct mtdoops_context { + struct kmsg_dumper dump; + int mtd_index; struct work_struct work_erase; struct work_struct work_write; @@ -49,14 +62,8 @@ static struct mtdoops_context { int nextpage; int nextcount; unsigned long *oops_page_used; - char *name; void *oops_buf; - - /* writecount and disabling ready are spin lock protected */ - spinlock_t writecount_lock; - int ready; - int writecount; } oops_cxt; static void mark_page_used(struct mtdoops_context *cxt, int page) @@ -108,7 +115,7 @@ static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset) remove_wait_queue(&wait_q, &wait); printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", (unsigned long long)erase.addr, - (unsigned long long)erase.len, mtd->name); + (unsigned long long)erase.len, mtddev); return ret; } @@ -138,7 +145,6 @@ static void mtdoops_inc_counter(struct mtdoops_context *cxt) printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", cxt->nextpage, cxt->nextcount); - cxt->ready = 1; } /* Scheduled work - when we can't proceed without erasing a block */ @@ -187,7 +193,6 @@ badblock: if (ret >= 0) { printk(KERN_DEBUG "mtdoops: ready %d, %d\n", cxt->nextpage, cxt->nextcount); - cxt->ready = 1; return; } @@ -205,11 +210,13 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic) { struct mtd_info *mtd = cxt->mtd; size_t retlen; + u32 *hdr; int ret; - if (cxt->writecount < record_size) - memset(cxt->oops_buf + cxt->writecount, 0xff, - record_size - cxt->writecount); + /* Add mtdoops header to the buffer */ + hdr = cxt->oops_buf; + hdr[0] = cxt->nextcount; + hdr[1] = MTDOOPS_KERNMSG_MAGIC; if (panic) ret = mtd->panic_write(mtd, cxt->nextpage * record_size, @@ -218,17 +225,15 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic) ret = mtd->write(mtd, cxt->nextpage * record_size, record_size, &retlen, cxt->oops_buf); - cxt->writecount = 0; - if (retlen != record_size || ret < 0) printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", cxt->nextpage * record_size, retlen, record_size, ret); mark_page_used(cxt, cxt->nextpage); + memset(cxt->oops_buf, 0xff, record_size); mtdoops_inc_counter(cxt); } - static void mtdoops_workfunc_write(struct work_struct *work) { struct mtdoops_context *cxt = @@ -247,10 +252,13 @@ static void find_next_position(struct mtdoops_context *cxt) for (page = 0; page < cxt->oops_pages; page++) { /* Assume the page is used */ mark_page_used(cxt, page); - ret = mtd->read(mtd, page * record_size, 8, &retlen, (u_char *) &count[0]); - if (retlen != 8 || (ret < 0 && ret != -EUCLEAN)) { - printk(KERN_ERR "mtdoops: read failure at %ld (%td of 8 read), err %d\n", - page * record_size, retlen, ret); + ret = mtd->read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, + &retlen, (u_char *) &count[0]); + if (retlen != MTDOOPS_HEADER_SIZE || + (ret < 0 && ret != -EUCLEAN)) { + printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", + page * record_size, retlen, + MTDOOPS_HEADER_SIZE, ret); continue; } @@ -287,7 +295,6 @@ static void find_next_position(struct mtdoops_context *cxt) } else { printk(KERN_DEBUG "mtdoops: ready %d, %d (clean)\n", cxt->nextpage, cxt->nextcount); - cxt->ready = 1; } return; } @@ -298,6 +305,42 @@ static void find_next_position(struct mtdoops_context *cxt) mtdoops_inc_counter(cxt); } +static void mtdoops_do_dump(struct kmsg_dumper *dumper, + enum kmsg_dump_reason reason, const char *s1, unsigned long l1, + const char *s2, unsigned long l2) +{ + struct mtdoops_context *cxt = container_of(dumper, + struct mtdoops_context, dump); + unsigned long s1_start, s2_start; + unsigned long l1_cpy, l2_cpy; + char *dst; + + /* Only dump oopses if dump_oops is set */ + if (reason == KMSG_DUMP_OOPS && !dump_oops) + return; + + dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */ + l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE); + l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy); + + s2_start = l2 - l2_cpy; + s1_start = l1 - l1_cpy; + + memcpy(dst, s1 + s1_start, l1_cpy); + memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); + + /* Panics must be written immediately */ + if (reason == KMSG_DUMP_PANIC) { + if (!cxt->mtd->panic_write) + printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); + else + mtdoops_write(cxt, 1); + return; + } + + /* For other cases, schedule work to write it "nicely" */ + schedule_work(&cxt->work_write); +} static void mtdoops_notify_add(struct mtd_info *mtd) { @@ -306,7 +349,7 @@ static void mtdoops_notify_add(struct mtd_info *mtd) do_div(mtdoops_pages, record_size); - if (cxt->name && !strcmp(mtd->name, cxt->name)) + if (!strcmp(mtd->name, mtddev)) cxt->mtd_index = mtd->index; if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) @@ -339,6 +382,8 @@ static void mtdoops_notify_add(struct mtd_info *mtd) find_next_position(cxt); + cxt->dump.dump = mtdoops_do_dump; + kmsg_dump_register(&cxt->dump); printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); } @@ -349,116 +394,27 @@ static void mtdoops_notify_remove(struct mtd_info *mtd) if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) return; + kmsg_dump_unregister(&cxt->dump); cxt->mtd = NULL; flush_scheduled_work(); } -static void mtdoops_console_sync(void) -{ - struct mtdoops_context *cxt = &oops_cxt; - struct mtd_info *mtd = cxt->mtd; - unsigned long flags; - - if (!cxt->ready || !mtd || cxt->writecount == 0) - return; - - /* - * Once ready is 0 and we've held the lock no further writes to the - * buffer will happen - */ - spin_lock_irqsave(&cxt->writecount_lock, flags); - if (!cxt->ready) { - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - return; - } - cxt->ready = 0; - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - - if (mtd->panic_write && (in_interrupt() || panic_on_oops)) - /* Interrupt context, we're going to panic so try and log */ - mtdoops_write(cxt, 1); - else - schedule_work(&cxt->work_write); -} - -static void -mtdoops_console_write(struct console *co, const char *s, unsigned int count) -{ - struct mtdoops_context *cxt = co->data; - struct mtd_info *mtd = cxt->mtd; - unsigned long flags; - - if (!oops_in_progress) { - mtdoops_console_sync(); - return; - } - - if (!cxt->ready || !mtd) - return; - - /* Locking on writecount ensures sequential writes to the buffer */ - spin_lock_irqsave(&cxt->writecount_lock, flags); - - /* Check ready status didn't change whilst waiting for the lock */ - if (!cxt->ready) { - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - return; - } - - if (cxt->writecount == 0) { - u32 *stamp = cxt->oops_buf; - *stamp++ = cxt->nextcount; - *stamp = MTDOOPS_KERNMSG_MAGIC; - cxt->writecount = 8; - } - - if (count + cxt->writecount > record_size) - count = record_size - cxt->writecount; - - memcpy(cxt->oops_buf + cxt->writecount, s, count); - cxt->writecount += count; - - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - - if (cxt->writecount == record_size) - mtdoops_console_sync(); -} - -static int __init mtdoops_console_setup(struct console *co, char *options) -{ - struct mtdoops_context *cxt = co->data; - - if (cxt->mtd_index != -1 || cxt->name) - return -EBUSY; - if (options) { - cxt->name = kstrdup(options, GFP_KERNEL); - return 0; - } - if (co->index == -1) - return -EINVAL; - - cxt->mtd_index = co->index; - return 0; -} static struct mtd_notifier mtdoops_notifier = { .add = mtdoops_notify_add, .remove = mtdoops_notify_remove, }; -static struct console mtdoops_console = { - .name = "ttyMTD", - .write = mtdoops_console_write, - .setup = mtdoops_console_setup, - .unblank = mtdoops_console_sync, - .index = -1, - .data = &oops_cxt, -}; - -static int __init mtdoops_console_init(void) +static int __init mtdoops_init(void) { struct mtdoops_context *cxt = &oops_cxt; + int mtd_index; + char *endp; + if (strlen(mtddev) == 0) { + printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); + return -EINVAL; + } if ((record_size & 4095) != 0) { printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); return -EINVAL; @@ -467,36 +423,39 @@ static int __init mtdoops_console_init(void) printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); return -EINVAL; } + + /* Setup the MTD device to use */ cxt->mtd_index = -1; + mtd_index = simple_strtoul(mtddev, &endp, 0); + if (endp != mtddev) + cxt->mtd_index = mtd_index; + cxt->oops_buf = vmalloc(record_size); if (!cxt->oops_buf) { printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); return -ENOMEM; } + memset(cxt->oops_buf, 0xff, record_size); - spin_lock_init(&cxt->writecount_lock); INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); - register_console(&mtdoops_console); register_mtd_user(&mtdoops_notifier); return 0; } -static void __exit mtdoops_console_exit(void) +static void __exit mtdoops_exit(void) { struct mtdoops_context *cxt = &oops_cxt; unregister_mtd_user(&mtdoops_notifier); - unregister_console(&mtdoops_console); - kfree(cxt->name); vfree(cxt->oops_buf); vfree(cxt->oops_page_used); } -subsys_initcall(mtdoops_console_init); -module_exit(mtdoops_console_exit); +module_init(mtdoops_init); +module_exit(mtdoops_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Richard Purdie ");