Commit 932bed41 authored by Sourabh Jain's avatar Sourabh Jain Committed by Michael Ellerman
Browse files

powerpc/kexec_file: fix cpus node update to FDT 



While updating the cpus node, commit 40c75399 ("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: 40c75399 ("powerpc/kexec_file: Use current CPU info while setting up FDT")
Signed-off-by: default avatarSourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240510102235.2269496-3-sourabhjain@linux.ibm.com
parent 0d3ff067

arch/powerpc/kexec/core_64.c

+37 −16
Original line number Diff line number Diff line
@@ -456,9 +456,15 @@ 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;
@@ -469,30 +475,44 @@ 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,
@@ -506,6 +526,7 @@ int update_cpus_node(void *fdt) 
			goto out;

	}

out:

	of_node_put(cpus_node);

	of_node_put(dn);

	return ret;

}