Hello all,
Using qemu, I was trying to compare A) the direct kernel loading (using
-kernel Image option) with B) running from u-boot to load kernel Image and
met with a problem.
When I load kernel directly using "-kernel Image" method for an arm64
virtual machine, it boots ok to the shell prompt.
In this situation, I examined where the kernel Image is loaded.
The qemu program (v.6.2.0) goes through this code in hw/arm/boot.c.
if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64) && kernel_size < 0) {
kernel_size = load_aarch64_image(info->kernel_filename,
info->loader_start, &entry, as);
is_linux = 1;
if (kernel_size >= 0) {
image_low_addr = entry;
image_high_addr = image_low_addr + kernel_size;
}
Inside load_aarch64_image function, I've checked, *entry becomes 0x80200000.
The Image file is loaded by this line there :
rom_add_blob_fixed_as(filename, buffer, size, *entry, as);
The rom_add_blob_fixed_as is eventually 'rom_add_blob' function and there,
the data is copied to a 'struct Rom' with the address set as 0x80200000 and
this Rom is added to 'roms' (list of Rom).
After this, I tried to read the memory at 0x80200000 to see if this kernel
Image is there but could not find it.
I used this method to see memory at 0x80200000 :
during the machab21q_init function,
Ram_ptr = memory_region_get_ram_ptr(machine->ram); // to the virtual
address of the memory in the host machine
In the (gdb), after kernel Image is loaded at 0x80200000.
(gdb) p ram_ptr
$6 = 0x7ffee2e00000
(gdb) p ram_ptr + 0x80200000
$7 = 0x7fff63000000
(gdb) x/16x $7
0x7fff63000000: 0x00000000 0x00000000 0x00000000 0x00000000
0x7fff63000010: 0x00000000 0x00000000 0x00000000 0x00000000
0x7fff63000020: 0x00000000 0x00000000 0x00000000 0x00000000
0x7fff63000030: 0x00000000 0x00000000 0x00000000 0x00000000
No data is there!
Is this because the kernel Image was loaded in one of the 'Rom' and not in
the memory??
Can't I really load the kernel Image at 0x80200000? (actually I want to load
it at 0x80000000).
Thank you for reading and any help will be really appreciated.
Chan Kim
