[Qemu-devel] [PATCH v2 4/4] hw/arm/boot: enable DTB support when booting ELF images

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

Add support for loading DTB images when booting ELF images using
-kernel. If there are no conflicts with the placement of the ELF
segments, the DTB image is loaded at the base of RAM.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 hw/arm/boot.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 1f73614d8843..3878cbd97aad 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -464,7 +464,7 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
     int kernel_size;
     int initrd_size;
     int is_linux = 0;
-    uint64_t elf_entry;
+    uint64_t elf_entry, elf_low_addr;
     int elf_machine;
     hwaddr entry, kernel_load_offset;
     int big_endian;
@@ -531,7 +531,19 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
 
     /* Assume that raw images are linux kernels, and ELF images are not.  */
     kernel_size = load_elf(info->kernel_filename, NULL, NULL, &elf_entry,
-                           NULL, NULL, big_endian, elf_machine, 1);
+                           &elf_low_addr, NULL, big_endian, elf_machine, 1);
+    if (kernel_size > 0 && have_dtb(info)) {
+        /* If there is still some room left between the base of RAM and the
+         * low end of the ELF image we just loaded, try and put the DTB at the
+         * base of RAM like we do for bootloaders. Just ignore the potential 0
+         * return value of load_dtb() which indicates that the dtb didn't fit,
+         * in that case we just proceed without it.
+         */
+        if (elf_low_addr > info->loader_start &&
+            load_dtb(info->loader_start, info, elf_low_addr) < 0) {
+            exit(1);
+        }
+    }
     entry = elf_entry;
     if (kernel_size < 0) {
         kernel_size = load_uimage(info->kernel_filename, &entry, NULL,
-- 
1.8.3.2