This is a note to let you know that I've just added the patch titled
powerpc/kexec_file: fix cpus node update to FDT
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-kexec_file-fix-cpus-node-update-to-fdt.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 383f31654bdad933173a7b183dbc8596a7fef422
Author: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
Date: Fri May 10 15:52:35 2024 +0530
powerpc/kexec_file: fix cpus node update to FDT
[ 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@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20240510102235.2269496-3-sourabhjain@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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;
}
