[PATCH v2 0/2] powerpc: kexec fixes

[PATCH v2 0/2] powerpc: kexec fixes

[Sourabh Jain]

Patch series fixes two kexec issues.

01/02: Update extra size calculation for kexec FDT to avoid kexec load
failure due to FDT_ERR_NOSPACE while including CPU nodes added post
boot and reserved memory ranges.

02/02: Fix update_cpus_node/core_64.c function to include missing device
nodes under /cpus node with device_type != "cpu".

Note: this patch series is rebased on top of the linux-next/master,
tag: next-20240509 to avoid the conflict with the below patch series:
https://lore.kernel.org/all/171509287314.62008.11812494124513471250.b4-ty@ellerman.id.au/

Changelog:
==========

v2:
  - Initialize local variable `cpu_nodes` before using it. 01/02
  - Rebased on top of linux-next/mater tag: next-20240509.

v1:
  - https://lore.kernel.org/all/20240508130558.1939304-1-sourabhjain@linux.ibm.com/


Cc: Aditya Gupta <adityag@linux.ibm.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>

Sourabh Jain (2):
  powerpc/kexec_file: fix extra size calculation for kexec FDT
  powerpc/kexec_file: fix cpus node update to FDT

 arch/powerpc/include/asm/kexec.h  |  6 ++--
 arch/powerpc/kexec/core_64.c      | 53 +++++++++++++++++++++----------
 arch/powerpc/kexec/elf_64.c       | 12 +++++--
 arch/powerpc/kexec/file_load_64.c | 53 +++++++++++++------------------
 4 files changed, 70 insertions(+), 54 deletions(-)

-- 
2.44.0

[PATCH v2 1/2] powerpc/kexec_file: fix extra size calculation for kexec FDT

[Sourabh Jain]

While setting up the FDT for kexec, CPU nodes that are added after the
system boots and reserved memory ranges are incorporated into the
initial_boot_params (base FDT).

However, they are not taken into account when determining the additional
size needed for the kexec FDT. As a result, kexec fails to load,
generating the following error:

[1116.774451] Error updating memory reserve map: FDT_ERR_NOSPACE
kexec_file_load failed: No such process

Therefore, consider the extra size for CPU nodes added post-system boot
and reserved memory ranges while preparing the kexec FDT.

While adding a new parameter to the setup_new_fdt_ppc64 function, it was
noticed that there were a couple of unused parameters, so they were
removed.

Cc: Aditya Gupta <adityag@linux.ibm.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
---

Changelog:

Since v1:
  - Initialize local variable `cpu_nodes` before using it. 01/02

---

 arch/powerpc/include/asm/kexec.h  |  6 ++--
 arch/powerpc/kexec/elf_64.c       | 12 +++++--
 arch/powerpc/kexec/file_load_64.c | 53 +++++++++++++------------------
 3 files changed, 33 insertions(+), 38 deletions(-)

diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 95a98b390d62..270ee93a0f7d 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -103,10 +103,8 @@ int load_crashdump_segments_ppc64(struct kimage *image,
 int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
 			  const void *fdt, unsigned long kernel_load_addr,
 			  unsigned long fdt_load_addr);
-unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image);
-int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
-			unsigned long initrd_load_addr,
-			unsigned long initrd_len, const char *cmdline);
+unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image, struct crash_mem *rmem);
+int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, struct crash_mem *rmem);
 #endif /* CONFIG_PPC64 */
 
 #endif /* CONFIG_KEXEC_FILE */
diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index 214c071c58ed..5d6d616404cf 100644
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c
@@ -23,6 +23,7 @@
 #include <linux/of_fdt.h>
 #include <linux/slab.h>
 #include <linux/types.h>
+#include <asm/kexec_ranges.h>
 
 static void *elf64_load(struct kimage *image, char *kernel_buf,
 			unsigned long kernel_len, char *initrd,
@@ -36,6 +37,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
 	const void *slave_code;
 	struct elfhdr ehdr;
 	char *modified_cmdline = NULL;
+	struct crash_mem *rmem = NULL;
 	struct kexec_elf_info elf_info;
 	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
 				  .buf_max = ppc64_rma_size };
@@ -102,17 +104,20 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
 		kexec_dprintk("Loaded initrd at 0x%lx\n", initrd_load_addr);
 	}
 
+	ret = get_reserved_memory_ranges(&rmem);
+	if (ret)
+		goto out;
+
 	fdt = of_kexec_alloc_and_setup_fdt(image, initrd_load_addr,
 					   initrd_len, cmdline,
-					   kexec_extra_fdt_size_ppc64(image));
+					   kexec_extra_fdt_size_ppc64(image, rmem));
 	if (!fdt) {
 		pr_err("Error setting up the new device tree.\n");
 		ret = -EINVAL;
 		goto out;
 	}
 
-	ret = setup_new_fdt_ppc64(image, fdt, initrd_load_addr,
-				  initrd_len, cmdline);
+	ret = setup_new_fdt_ppc64(image, fdt, rmem);
 	if (ret)
 		goto out_free_fdt;
 
@@ -146,6 +151,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
 out_free_fdt:
 	kvfree(fdt);
 out:
+	kfree(rmem);
 	kfree(modified_cmdline);
 	kexec_free_elf_info(&elf_info);
 
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index 925a69ad2468..413c76de283d 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -803,10 +803,9 @@ static unsigned int cpu_node_size(void)
 	return size;
 }
 
-static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image)
+static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image, unsigned int cpu_nodes)
 {
-	unsigned int cpu_nodes, extra_size = 0;
-	struct device_node *dn;
+	unsigned int extra_size = 0;
 	u64 usm_entries;
 #ifdef CONFIG_CRASH_HOTPLUG
 	unsigned int possible_cpu_nodes;
@@ -826,18 +825,6 @@ static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image)
 		extra_size += (unsigned int)(usm_entries * sizeof(u64));
 	}
 
-	/*
-	 * Get the number of CPU nodes in the current DT. This allows to
-	 * reserve places for CPU nodes added since the boot time.
-	 */
-	cpu_nodes = 0;
-	for_each_node_by_type(dn, "cpu") {
-		cpu_nodes++;
-	}
-
-	if (cpu_nodes > boot_cpu_node_count)
-		extra_size += (cpu_nodes - boot_cpu_node_count) * cpu_node_size();
-
 #ifdef CONFIG_CRASH_HOTPLUG
 	/*
 	 * Make sure enough space is reserved to accommodate possible CPU nodes
@@ -861,16 +848,30 @@ static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image)
  *
  * Returns the estimated extra size needed for kexec/kdump kernel FDT.
  */
-unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
+unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image, struct crash_mem *rmem)
 {
-	unsigned int extra_size = 0;
+	struct device_node *dn;
+	unsigned int cpu_nodes = 0, extra_size = 0;
 
 	// Budget some space for the password blob. There's already extra space
 	// for the key name
 	if (plpks_is_available())
 		extra_size += (unsigned int)plpks_get_passwordlen();
 
-	return extra_size + kdump_extra_fdt_size_ppc64(image);
+	/* Get the number of CPU nodes in the current device tree */
+	for_each_node_by_type(dn, "cpu") {
+		cpu_nodes++;
+	}
+
+	/* Consider extra space for CPU nodes added since the boot time */
+	if (cpu_nodes > boot_cpu_node_count)
+		extra_size += (cpu_nodes - boot_cpu_node_count) * cpu_node_size();
+
+	/* Consider extra space for reserved memory ranges if any */
+	if (rmem->nr_ranges > 0)
+		extra_size += sizeof(struct fdt_reserve_entry) * rmem->nr_ranges;
+
+	return extra_size + kdump_extra_fdt_size_ppc64(image, cpu_nodes);
 }
 
 static int copy_property(void *fdt, int node_offset, const struct device_node *dn,
@@ -924,18 +925,13 @@ static int update_pci_dma_nodes(void *fdt, const char *dmapropname)
  *                       being loaded.
  * @image:               kexec image being loaded.
  * @fdt:                 Flattened device tree for the next kernel.
- * @initrd_load_addr:    Address where the next initrd will be loaded.
- * @initrd_len:          Size of the next initrd, or 0 if there will be none.
- * @cmdline:             Command line for the next kernel, or NULL if there will
- *                       be none.
+ * @rmem:                Reserved memory ranges.
  *
  * Returns 0 on success, negative errno on error.
  */
-int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
-			unsigned long initrd_load_addr,
-			unsigned long initrd_len, const char *cmdline)
+int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, struct crash_mem *rmem)
 {
-	struct crash_mem *umem = NULL, *rmem = NULL;
+	struct crash_mem *umem = NULL;
 	int i, nr_ranges, ret;
 
 #ifdef CONFIG_CRASH_DUMP
@@ -991,10 +987,6 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
 		goto out;
 
 	/* Update memory reserve map */
-	ret = get_reserved_memory_ranges(&rmem);
-	if (ret)
-		goto out;
-
 	nr_ranges = rmem ? rmem->nr_ranges : 0;
 	for (i = 0; i < nr_ranges; i++) {
 		u64 base, size;
@@ -1014,7 +1006,6 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
 		ret = plpks_populate_fdt(fdt);
 
 out:
-	kfree(rmem);
 	kfree(umem);
 	return ret;
 }
-- 
2.44.0

[PATCH v2 2/2] powerpc/kexec_file: fix cpus node update to FDT

[Sourabh Jain]

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")
Cc: Aditya Gupta <adityag@linux.ibm.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
---

* No changes in v2.

---

 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 85050be08a23..2e625c2cb6b9 100644
--- a/arch/powerpc/kexec/core_64.c
+++ b/arch/powerpc/kexec/core_64.c
@@ -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;
 }
-- 
2.44.0