Merge patch series "riscv: kexec_file: Support loading Image binary file"

Björn Töpel <bjorn@kernel.org> says:

From: Björn Töpel <bjorn@rivosinc.com>

Hi!

For over a year ago, Daniel and I was testing the V2 of Song's series.
I also promised to take the V2, that had been sitting on the lists for
too long, to rebase it on a new kernel, and re-test it.

One year later, here's the V3! ;-)

There are no changes from V2 other, than some simple checkpatch
cleanups.

Song's original cover:
  | This series makes the kexec_file_load() syscall support to load
  | Image binary file. At the same time, corresponding support for
  | kexec-tools had been pushed to my repo[2].
  |
  | Now, we can leverage that kexec-tools and this series to use the
  | kexec_load() or kexec_file_load() syscall to boot both vmlinux and
  | Image file, as seen in these combo tests:
  |
  | ```
  | 1. kexec -l vmlinux
  | 2. kexec -l Image
  | 3. kexec -s -l vmlinux
  | 4. kexec -s -l Image
  | ```

Notably, kexec-tools has still not made it upstream. I've prepared a
branch on my GH [3], that I indend to post ASAP. That branch is a
collection of fixes/features, including Song's userland Image loading.

The V2 is here [2], and V1 [1].

I've tested the kexec-file/Image on qemu-rv64, with following
combinations:
 * ACPI/UEFI
 * DT/UEFI
 * DT

both "regular" kexec (-s + -e), and crashkernels (-p).

Note that there are two purgatory patches that has to be present (part
of -rc1, so all good):
  commit 28093cf ("riscv/kexec_file: Handle R_RISCV_64 in purgatory relocator")
  commit 3f70231 ("riscv/purgatory: 4B align purgatory_start")

[1] https://lore.kernel.org/linux-riscv/20230914020044.1397356-1-songshuaishuai@tinylab.org/
[2] https://lore.kernel.org/linux-riscv/20231016092006.3347632-1-songshuaishuai@tinylab.org/
[3] https://github.com/bjoto/kexec-tools/tree/rv-on-master

* patches from https://lore.kernel.org/r/20250409193004.643839-1-bjorn@kernel.org:
  riscv: kexec_file: Support loading Image binary file
  riscv: kexec_file: Split the loading of kernel and others

Link: https://lore.kernel.org/r/20250409193004.643839-1-bjorn@kernel.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

Author: palmer-dabbelt

arch/riscv/include/asm/image.h

@@ -30,6 +30,8 @@
 			      RISCV_HEADER_VERSION_MINOR)
 
 #ifndef __ASSEMBLY__
+#define riscv_image_flag_field(flags, field)\
+			       (((flags) >> field##_SHIFT) & field##_MASK)
 /**
  * struct riscv_image_header - riscv kernel image header
  * @code0:		Executable code

arch/riscv/include/asm/kexec.h

@@ -56,6 +56,7 @@ extern riscv_kexec_method riscv_kexec_norelocate;
 
 #ifdef CONFIG_KEXEC_FILE
 extern const struct kexec_file_ops elf_kexec_ops;
+extern const struct kexec_file_ops image_kexec_ops;
 
 struct purgatory_info;
 int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
@@ -67,6 +68,11 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 struct kimage;
 int arch_kimage_file_post_load_cleanup(struct kimage *image);
 #define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup
+
+int load_extra_segments(struct kimage *image, unsigned long kernel_start,
+			unsigned long kernel_len, char *initrd,
+			unsigned long initrd_len, char *cmdline,
+			unsigned long cmdline_len);
 #endif
 
 #endif

arch/riscv/kernel/Makefile

@@ -107,7 +107,7 @@ obj-$(CONFIG_HOTPLUG_CPU)	+= cpu-hotplug.o
 obj-$(CONFIG_PARAVIRT)		+= paravirt.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_KEXEC_CORE)	+= kexec_relocate.o crash_save_regs.o machine_kexec.o
-obj-$(CONFIG_KEXEC_FILE)	+= elf_kexec.o machine_kexec_file.o
+obj-$(CONFIG_KEXEC_FILE)	+= kexec_elf.o kexec_image.o machine_kexec_file.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o