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Re: [Qemu-devel] [PATCH v2 4/4] hw/arm/boot: enable DTB support when boo
From: |
Ard Biesheuvel |
Subject: |
Re: [Qemu-devel] [PATCH v2 4/4] hw/arm/boot: enable DTB support when booting ELF images |
Date: |
Wed, 10 Sep 2014 13:28:03 +0200 |
On 10 September 2014 13:21, Peter Maydell <address@hidden> wrote:
> On 10 September 2014 11:59, Ard Biesheuvel <address@hidden> wrote:
>> 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 <address@hidden>
>> ---
>> 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);
>> + }
>> + }
>
> The conditional means we won't try to load the DTB even if the
> ELF file fit into the address space entirely below loader_start,
> which doesn't look right.
>
Ah right, I though loader_start was the start of usable RAM
What about assigning elf_high_addr as well, and changing the test to
if ((elf_low_addr > info->loader_start
|| elf_high_addr < info_loader_start)
&& load_dtb(info->loader_start, info,
(elf_high_addr < info_loader_start) ? 0 : elf_low_addr) < 0) {