powerpc/kexec: make the update_cpus_node() function public

JIRA: https://issues.redhat.com/browse/RHEL-101851

commit 0857bef
Author: Sourabh Jain <sourabhjain@linux.ibm.com>
Date:   Tue Mar 26 11:24:11 2024 +0530

    powerpc/kexec: make the update_cpus_node() function public

    Move the update_cpus_node() from kexec/{file_load_64.c => core_64.c}
    to allow other kexec components to use it.

    Later in the series, this function is used for in-kernel updates
    to the kdump image during CPU/memory hotplug or online/offline events for
    both kexec_load and kexec_file_load syscalls.

    No functional changes are intended.

    Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
    Acked-by: Hari Bathini <hbathini@linux.ibm.com>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://msgid.link/20240326055413.186534-5-sourabhjain@linux.ibm.com

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

Author: Mamatha Inamdar

arch/powerpc/include/asm/kexec.h

@@ -184,6 +184,10 @@ static inline void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 
 #endif /* CONFIG_CRASH_DUMP */
 
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_DUMP)
+int update_cpus_node(void *fdt);
+#endif
+
 #ifdef CONFIG_PPC_BOOK3S_64
 #include <asm/book3s/64/kexec.h>
 #endif

arch/powerpc/kexec/core_64.c

@@ -17,6 +17,7 @@
 #include <linux/cpu.h>
 #include <linux/hardirq.h>
 #include <linux/of.h>
+#include <linux/libfdt.h>
 
 #include <asm/page.h>
 #include <asm/current.h>
@@ -32,6 +33,7 @@
 #include <asm/asm-prototypes.h>
 #include <asm/svm.h>
 #include <asm/ultravisor.h>
+#include <asm/crashdump-ppc64.h>
 
 int machine_kexec_prepare(struct kimage *image)
 {
@@ -430,3 +432,92 @@ static int __init export_htab_values(void)
 }
 late_initcall(export_htab_values);
 #endif /* CONFIG_PPC_64S_HASH_MMU */
+
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_DUMP)
+/**
+ * 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.
+ */
+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;
+}
+#endif /* CONFIG_KEXEC_FILE || CONFIG_CRASH_DUMP */

arch/powerpc/kexec/file_load_64.c

@@ -835,93 +835,6 @@ unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
 	return extra_size + kdump_extra_fdt_size_ppc64(image);
 }
 
-/**
- * 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;
-}
-
 static int copy_property(void *fdt, int node_offset, const struct device_node *dn,
 			 const char *propname)
 {