[PATCH 1/3] multiboot2: Correct MBI size calculation

[Simon Horman]

On Fri, Sep 10, 2021 at 07:48:58PM -0700, Zhaofeng Li wrote:
> tag_load_base_addr is dependent on rel_tag, and tag_framebuffer was
> not accounted for.
> 
> Signed-off-by: Zhaofeng Li <hello at zhaofeng.li>
> ---
>  kexec/arch/i386/kexec-mb2-x86.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/kexec/arch/i386/kexec-mb2-x86.c b/kexec/arch/i386/kexec-mb2-x86.c
> index b4996bc..c10c0ef 100644
> --- a/kexec/arch/i386/kexec-mb2-x86.c
> +++ b/kexec/arch/i386/kexec-mb2-x86.c
> @@ -115,17 +115,24 @@ void multiboot2_x86_usage(void)
>  static size_t
>  multiboot2_get_mbi_size(int ranges, int cmdline_size, int modcount, int modcmd_size)
>  {
> -	return (2 * sizeof (uint32_t) + sizeof (struct multiboot_tag)
> -		+ sizeof (struct multiboot_tag)
> +	size_t mbi_size = (2 * sizeof (uint32_t) /* u32 total_size, u32 reserved */

nit: as this is multi-line, please declare  mbi_size and then use it.

	size_t mbi_size;

	mbi_size = ...

>  		+ ALIGN_UP (sizeof (struct multiboot_tag_basic_meminfo), MULTIBOOT_TAG_ALIGN)
>  		+ ALIGN_UP ((sizeof (struct multiboot_tag_mmap)
>  			+ ranges * sizeof (struct multiboot_mmap_entry)), MULTIBOOT_TAG_ALIGN)
> -		+ ALIGN_UP (sizeof (struct multiboot_tag_load_base_addr), MULTIBOOT_TAG_ALIGN)
>  		+ (sizeof (struct multiboot_tag_string)
>  			+ ALIGN_UP (cmdline_size, MULTIBOOT_TAG_ALIGN))
>  		+ (sizeof (struct multiboot_tag_string)
>  			+ ALIGN_UP (strlen(BOOTLOADER " " BOOTLOADER_VERSION) + 1, MULTIBOOT_TAG_ALIGN))
> -		+ (modcount * sizeof (struct multiboot_tag_module) + modcmd_size));
> +		+ (modcount * sizeof (struct multiboot_tag_module) + modcmd_size))
> +		+ sizeof (struct multiboot_tag); /* end tag */
> +
> +	if (mhi.rel_tag) mbi_size +=
> +		  ALIGN_UP (sizeof (struct multiboot_tag_load_base_addr), MULTIBOOT_TAG_ALIGN);

nit: please use the following coding style:

	if (mhi.rel_tag)
		mbi_size += ALIGN_UP (sizeof (struct multiboot_tag_load_base_addr), MULTIBOOT_TAG_ALIGN);

> +
> +	if (mhi.fb_tag) mbi_size +=
> +		  ALIGN_UP (sizeof (struct multiboot_tag_framebuffer), MULTIBOOT_TAG_ALIGN);
> +
> +	return mbi_size;
>  }
>  
>  static void multiboot2_read_header_tags(void)