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Thu, 29 Apr 2021 06:03:07 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 13T6341n23920960 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 29 Apr 2021 06:03:04 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 08A7C52054; Thu, 29 Apr 2021 06:03:04 +0000 (GMT) Received: from sjain014.ibmuc.com (unknown [9.199.60.55]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 19FA75204F; Thu, 29 Apr 2021 06:03:01 +0000 (GMT) From: Sourabh Jain To: mpe@ellerman.id.au Subject: [PATCH v7] powerpc/kexec_file: use current CPU info while setting up FDT Date: Thu, 29 Apr 2021 11:32:56 +0530 Message-Id: <20210429060256.199714-1-sourabhjain@linux.ibm.com> X-Mailer: git-send-email 2.26.3 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: QKBLoSZkQuuOPoM4haoZWd-MZKbXBatI X-Proofpoint-ORIG-GUID: QKBLoSZkQuuOPoM4haoZWd-MZKbXBatI Content-Transfer-Encoding: 8bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391, 18.0.761 definitions=2021-04-29_03:2021-04-28, 2021-04-29 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 lowpriorityscore=0 mlxlogscore=999 mlxscore=0 priorityscore=1501 impostorscore=0 clxscore=1015 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104290042 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mahesh@linux.vnet.ibm.com, Sourabh Jain , linuxppc-dev@ozlabs.org, stable@vger.kernel.org, hbathini@linux.ibm.com, bauerman@linux.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" kexec_file_load uses initial_boot_params in setting up the device-tree for the kernel to be loaded. Though initial_boot_params holds info about CPUs at the time of boot, it doesn't account for hot added CPUs. So, kexec'ing with kexec_file_load syscall would leave the kexec'ed kernel with inaccurate CPU info. Also, if kdump kernel is loaded with kexec_file_load syscall and the system crashes on a hot added CPU, capture kernel hangs failing to identify the boot CPU. Kernel panic - not syncing: sysrq triggered crash CPU: 24 PID: 6065 Comm: echo Kdump: loaded Not tainted 5.12.0-rc5upstream #54 Call Trace: [c0000000e590fac0] [c0000000007b2400] dump_stack+0xc4/0x114 (unreliable) [c0000000e590fb00] [c000000000145290] panic+0x16c/0x41c [c0000000e590fba0] [c0000000008892e0] sysrq_handle_crash+0x30/0x40 [c0000000e590fc00] [c000000000889cdc] __handle_sysrq+0xcc/0x1f0 [c0000000e590fca0] [c00000000088a538] write_sysrq_trigger+0xd8/0x178 [c0000000e590fce0] [c0000000005e9b7c] proc_reg_write+0x10c/0x1b0 [c0000000e590fd10] [c0000000004f26d0] vfs_write+0xf0/0x330 [c0000000e590fd60] [c0000000004f2aec] ksys_write+0x7c/0x140 [c0000000e590fdb0] [c000000000031ee0] system_call_exception+0x150/0x290 [c0000000e590fe10] [c00000000000ca5c] system_call_common+0xec/0x278 --- interrupt: c00 at 0x7fff905b9664 NIP: 00007fff905b9664 LR: 00007fff905320c4 CTR: 0000000000000000 REGS: c0000000e590fe80 TRAP: 0c00 Not tainted (5.12.0-rc5upstream) MSR: 800000000280f033 CR: 28000242 XER: 00000000 IRQMASK: 0 GPR00: 0000000000000004 00007ffff5fedf30 00007fff906a7300 0000000000000001 GPR04: 000001002a7355b0 0000000000000002 0000000000000001 00007ffff5fef616 GPR08: 0000000000000001 0000000000000000 0000000000000000 0000000000000000 GPR12: 0000000000000000 00007fff9073a160 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 00007fff906a4ee0 0000000000000002 0000000000000001 GPR24: 00007fff906a0898 0000000000000000 0000000000000002 000001002a7355b0 GPR28: 0000000000000002 00007fff906a1790 000001002a7355b0 0000000000000002 NIP [00007fff905b9664] 0x7fff905b9664 LR [00007fff905320c4] 0x7fff905320c4 --- interrupt: c00 To avoid this from happening, extract current CPU info from of_root device node and use it for setting up the fdt in kexec_file_load case. Fixes: 6ecd0163d360 ("powerpc/kexec_file: Add appropriate regions for memory reserve map") Signed-off-by: Sourabh Jain Reviewed-by: Hari Bathini Cc: --- arch/powerpc/kexec/file_load_64.c | 92 +++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) --- Changelog: v1 -> v5 - https://lists.ozlabs.org/pipermail/linuxppc-dev/2021-April/227950.html v5 -> v6 - use exiting macro (for_each_property_of_node) to loop through all properties of a node. - removed devtree_lock while accessing the node properties. - function name update, add_node_prop to add_node_props. v6 -> v7 - decrement the cpus_node refcount. --- diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c index 02b9e4d0dc40..a8a7cb71086b 100644 --- a/arch/powerpc/kexec/file_load_64.c +++ b/arch/powerpc/kexec/file_load_64.c @@ -960,6 +960,93 @@ unsigned int kexec_fdt_totalsize_ppc64(struct kimage *image) return fdt_size; } +/** + * add_node_props - Reads node properties from device node structure and add + * them to fdt. + * @fdt: Flattened device tree of the kernel + * @node_offset: offset of the node to add a property at + * @dn: device node pointer + * + * Returns 0 on success, negative errno on error. + */ +static int add_node_props(void *fdt, int node_offset, const struct device_node *dn) +{ + int ret = 0; + struct property *pp; + + if (!dn) + return -EINVAL; + + for_each_property_of_node(dn, pp) { + ret = fdt_setprop(fdt, node_offset, pp->name, pp->value, pp->length); + if (ret < 0) { + pr_err("Unable to add %s property: %s\n", pp->name, fdt_strerror(ret)); + return ret; + } + } + return ret; +} + +/** + * update_cpus_node - Update cpus node of flattened device tree using of_root + * device node. + * @fdt: Flattened device tree of the kernel. + * + * Returns 0 on success, negative errno on error. + */ +static int update_cpus_node(void *fdt) +{ + struct device_node *cpus_node, *dn; + int cpus_offset, cpus_subnode_offset, ret = 0; + + cpus_offset = fdt_path_offset(fdt, "/cpus"); + if (cpus_offset < 0 && cpus_offset != -FDT_ERR_NOTFOUND) { + pr_err("Malformed device tree: error reading /cpus node: %s\n", + fdt_strerror(cpus_offset)); + return cpus_offset; + } + + if (cpus_offset > 0) { + ret = fdt_del_node(fdt, cpus_offset); + if (ret < 0) { + pr_err("Error deleting /cpus node: %s\n", fdt_strerror(ret)); + return -EINVAL; + } + } + + /* Add cpus node to fdt */ + cpus_offset = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), "cpus"); + if (cpus_offset < 0) { + pr_err("Error creating /cpus node: %s\n", fdt_strerror(cpus_offset)); + return -EINVAL; + } + + /* Add cpus node properties */ + cpus_node = of_find_node_by_path("/cpus"); + ret = add_node_props(fdt, cpus_offset, cpus_node); + of_node_put(cpus_node); + if (ret < 0) + return ret; + + /* Loop through all subnodes of cpus and add them to fdt */ + for_each_node_by_type(dn, "cpu") { + cpus_subnode_offset = fdt_add_subnode(fdt, cpus_offset, dn->full_name); + if (cpus_subnode_offset < 0) { + pr_err("Unable to add %s subnode: %s\n", dn->full_name, + fdt_strerror(cpus_subnode_offset)); + ret = cpus_subnode_offset; + goto out; + } + + ret = add_node_props(fdt, cpus_subnode_offset, dn); + if (ret < 0) + goto out; + } +out: + of_node_put(dn); + return ret; +} + /** * setup_new_fdt_ppc64 - Update the flattend device-tree of the kernel * being loaded. @@ -1020,6 +1107,11 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, } } + /* Update cpus nodes information to account hotplug CPUs. */ + ret = update_cpus_node(fdt); + if (ret < 0) + goto out; + /* Update memory reserve map */ ret = get_reserved_memory_ranges(&rmem); if (ret) -- 2.26.3