Rob Herring [off-list ref] writes:

On Thu, Feb 4, 2021 at 10:42 AM Lakshmi Ramasubramanian
[off-list ref] wrote:

...

quoted

diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index d0e459bb2f05..51d2d8eb6c1b 100644
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c

@@ -19,6 +19,7 @@
 #include <linux/kexec.h>
 #include <linux/libfdt.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/slab.h>
 #include <linux/types.h>

@@ -32,7 +33,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
        unsigned int fdt_size;
        unsigned long kernel_load_addr;
        unsigned long initrd_load_addr = 0, fdt_load_addr;
-       void *fdt;
+       void *fdt = NULL;
        const void *slave_code;
        struct elfhdr ehdr;
        char *modified_cmdline = NULL;

@@ -103,18 +104,12 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
        }

        fdt_size = fdt_totalsize(initial_boot_params) * 2;
-       fdt = kmalloc(fdt_size, GFP_KERNEL);
+       fdt = of_alloc_and_init_fdt(fdt_size);
        if (!fdt) {
                pr_err("Not enough memory for the device tree.\n");
                ret = -ENOMEM;
                goto out;
        }
-       ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
-       if (ret < 0) {
-               pr_err("Error setting up the new device tree.\n");
-               ret = -EINVAL;
-               goto out;
-       }

        ret = setup_new_fdt_ppc64(image, fdt, initrd_load_addr,

The first thing this function does is call setup_new_fdt() which first
calls of_kexec_setup_new_fdt(). (Note, I really don't understand the
PPC code split. It looks like there's a 32-bit and 64-bit split, but
32-bit looks broken to me. Nothing ever calls setup_new_fdt() except
setup_new_fdt_ppc64()).

I think that's because 32-bit doesn't support kexec_file_load().

cheers