Re: [Xen-devel] [PATCH v8 13/13] x86: add multiboot2 protocol support for relocatable images

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 29.09.16 at 00:51, <daniel.kiper@xxxxxxxxxx> wrote:
> @@ -384,6 +391,15 @@ __start:
>          cmp     %edi,MB2_fixed_total_size(%ebx)
>          jbe     trampoline_bios_setup
>  
> +        /* Get Xen image load base address from Multiboot2 information. */
> +        cmpl    $MULTIBOOT2_TAG_TYPE_LOAD_BASE_ADDR,MB2_tag_type(%ecx)
> +        jne     1f
> +
> +        mov     MB2_load_base_addr(%ecx),%esi
> +        sub     $XEN_IMG_OFFSET,%esi
> +        jmp     9f
> +
> +1:
>          /* Get mem_lower from Multiboot2 information. */
>          cmpl    $MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO,MB2_tag_type(%ecx)
>          cmove   MB2_mem_lower(%ecx),%edx

This demonstrates the downsides of using numeric labels for other
than branching across a few instructions: Without digging out where
(and which) other patch places that label, it is impossible to judge
whether this is correct now. If the label had been a suitably named
.L one, this would be much less of a problem (and much easier to
look for in the other patches).

Jan


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