6.1-stable review patch. If anyone has any objections, please let me know.
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From: Sourabh Jain sourabhjain@linux.ibm.com
[ Upstream commit 932bed41217059638c78a75411b7893b121d2162 ]
While updating the cpus node, commit 40c753993e3a ("powerpc/kexec_file: Use current CPU info while setting up FDT") first deletes all subnodes under the /cpus node. However, while adding sub-nodes back, it missed adding cpus subnodes whose device_type != "cpu", such as l2-cache*, l3-cache*, ibm,powerpc-cpu-features.
Fix this by only deleting cpus sub-nodes of device_type == "cpus" and then adding all available nodes with device_type == "cpu".
Fixes: 40c753993e3a ("powerpc/kexec_file: Use current CPU info while setting up FDT") Signed-off-by: Sourabh Jain sourabhjain@linux.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://msgid.link/20240510102235.2269496-3-sourabhjain@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kexec/core_64.c | 53 +++++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c index 8a33de499316e..653b3c8c6a530 100644 --- a/arch/powerpc/kexec/core_64.c +++ b/arch/powerpc/kexec/core_64.c @@ -468,9 +468,15 @@ static int add_node_props(void *fdt, int node_offset, const struct device_node * * @fdt: Flattened device tree of the kernel. * * Returns 0 on success, negative errno on error. + * + * Note: expecting no subnodes under /cpus/<node> with device_type == "cpu". + * If this changes, update this function to include them. */ int update_cpus_node(void *fdt) { + int prev_node_offset; + const char *device_type; + const struct fdt_property *prop; struct device_node *cpus_node, *dn; int cpus_offset, cpus_subnode_offset, ret = 0;
@@ -481,30 +487,44 @@ int update_cpus_node(void *fdt) return cpus_offset; }
- if (cpus_offset > 0) { - ret = fdt_del_node(fdt, cpus_offset); + prev_node_offset = cpus_offset; + /* Delete sub-nodes of /cpus node with device_type == "cpu" */ + for (cpus_subnode_offset = fdt_first_subnode(fdt, cpus_offset); cpus_subnode_offset >= 0;) { + /* Ignore nodes that do not have a device_type property or device_type != "cpu" */ + prop = fdt_get_property(fdt, cpus_subnode_offset, "device_type", NULL); + if (!prop || strcmp(prop->data, "cpu")) { + prev_node_offset = cpus_subnode_offset; + goto next_node; + } + + ret = fdt_del_node(fdt, cpus_subnode_offset); if (ret < 0) { - pr_err("Error deleting /cpus node: %s\n", fdt_strerror(ret)); - return -EINVAL; + pr_err("Failed to delete a cpus sub-node: %s\n", fdt_strerror(ret)); + return ret; } +next_node: + if (prev_node_offset == cpus_offset) + cpus_subnode_offset = fdt_first_subnode(fdt, cpus_offset); + else + cpus_subnode_offset = fdt_next_subnode(fdt, prev_node_offset); }
- /* 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)); + cpus_node = of_find_node_by_path("/cpus"); + /* Fail here to avoid kexec/kdump kernel boot hung */ + if (!cpus_node) { + pr_err("No /cpus node found\n"); 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; + /* Add all /cpus sub-nodes of device_type == "cpu" to FDT */ + for_each_child_of_node(cpus_node, dn) { + /* Ignore device nodes that do not have a device_type property + * or device_type != "cpu". + */ + device_type = of_get_property(dn, "device_type", NULL); + if (!device_type || strcmp(device_type, "cpu")) + continue;
- /* 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, @@ -518,6 +538,7 @@ int update_cpus_node(void *fdt) goto out; } out: + of_node_put(cpus_node); of_node_put(dn); return ret; }