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Violators will be prosecuted; Fri, 20 Apr 2018 06:04:30 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w3K54T7s11796606; Fri, 20 Apr 2018 05:04:29 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3B6C8A4053; Fri, 20 Apr 2018 05:56:35 +0100 (BST) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 53EFFA4040; Fri, 20 Apr 2018 05:56:33 +0100 (BST) Received: from jupiter.in.ibm.com (unknown [9.109.202.29]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 20 Apr 2018 05:56:33 +0100 (BST) Subject: [PATCH v4 2/7] powerpc/fadump: Update documentation to reflect the metadata region movement. From: Mahesh J Salgaonkar To: linuxppc-dev Date: Fri, 20 Apr 2018 10:34:26 +0530 In-Reply-To: <152420062000.31037.770773018944092449.stgit@jupiter.in.ibm.com> References: <152420062000.31037.770773018944092449.stgit@jupiter.in.ibm.com> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 18042005-0020-0000-0000-00000413EE93 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18042005-0021-0000-0000-000042A83F02 Message-Id: <152420066675.31037.4888400094785392534.stgit@jupiter.in.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-04-20_01:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804200047 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ananth Narayan , kernelfans@gmail.com, "Aneesh Kumar K.V" , Hari Bathini , Nathan Fontenot , Anshuman Khandual , Srikar Dronamraju Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Mahesh Salgaonkar Metadata region that holds fadump header and ELF header is now placed at the start of reserved memory area. Update the documentation accordingly Signed-off-by: Mahesh Salgaonkar --- Documentation/powerpc/firmware-assisted-dump.txt | 33 ++++++++++++++-------- 1 file changed, 21 insertions(+), 12 deletions(-) diff --git a/Documentation/powerpc/firmware-assisted-dump.txt b/Documentation/powerpc/firmware-assisted-dump.txt index bdd344aa18d9..30b32f879219 100644 --- a/Documentation/powerpc/firmware-assisted-dump.txt +++ b/Documentation/powerpc/firmware-assisted-dump.txt @@ -115,17 +115,26 @@ be kept permanently reserved, so that it can act as a receptacle for a copy of the boot memory content in addition to CPU state and HPTE region, in the case a crash does occur. +The first kernel, during fadump registration, prepares ELF core header +that contains necessary information for the coredump of the 1st kernel +which includes its physical memory layout. This ELF header and some more +additional data is stored in the area called metadata region at the start +of the reserved memory area. The implementation maintains the compatibility +between production/capture kernels irrespective of their kernel versions. +Both combination older/newer and newer/older works fine. + o Memory Reservation during first kernel Low memory Top of memory 0 boot memory size | | | |<--Reserved dump area -->| | V V | Permanent Reservation | V - +-----------+----------/ /---+---+----+-----------+----+------+ - | | |CPU|HPTE| DUMP |ELF | | - +-----------+----------/ /---+---+----+-----------+----+------+ - | ^ - | | + +-----------+----------/ /---+----+---+----+-----------+------+ + | | |ELF |CPU|HPTE| DUMP | | + +-----------+---------/ /----+----+---+----+-----------+------+ + | ^ ^ + | | | + | metadata region | \ / ------------------------------------------- Boot memory content gets transferred to @@ -137,14 +146,14 @@ and HPTE region, in the case a crash does occur. Low memory Top of memory 0 boot memory size | - | |<------------- Reserved dump area ----------- -->| + | |<------------- Reserved dump area -------------->| V V V - +-----------+----------/ /---+---+----+-----------+----+------+ - | | |CPU|HPTE| DUMP |ELF | | - +-----------+----------/ /---+---+----+-----------+----+------+ - | | - V V - Used by second /proc/vmcore + +-----------+----------/ /---+----+----+---------------+------+ + | | |ELF |CPU|HPTE| DUMP | | + +-----------+----------/ /---+----+----+---------------+------+ + | | + V V + Used by second /proc/vmcore kernel to boot Fig. 2