Re: [PATCH v2 1/1] x86/Documentation: Update algo in init_size description of boot protocol

[Randy Dunlap]

On 11/25/24 2:49 AM, Andy Shevchenko wrote:
> The init_size description of boot protocol has an example of the runtime
> start address for the compressed bzImage. For non-relocatable kernel
> it relies on the pref_address value (if not 0), but for relocatable case
> only pays respect to the load_addres and kernel_alignment, and it is
> inaccurate for the latter. Boot loader must consider the pref_address
> as the Linux kernel relocates to it before being decompressed as nicely
> described in the commit 43b1d3e68ee7 message.
> 
> Due to this inaccuracy some of the bootloaders (*) made a mistake in
> the calculations and if kernel image is big enough, this may lead to
> unbootable configurations.
> 
> *)
>   In particular, kexec-tools missed that and resently got a couple of
>   changes which will be part of v2.0.30 release. For the record,
>   the 43b1d3e68ee7 fixed only kernel kexec implementation and also missed
>   to update the init_size description.
> 
> While at it, make an example C-like looking as it's done elsewhere in
> the document and fix indentation as presribed by the reStructuredText
> specifications, so the syntax highliting will work properly.
> 
> Fixes: 43b1d3e68ee7 ("kexec: Allocate kernel above bzImage's pref_address")
> Fixes: d297366ba692 ("x86: document new bzImage fields")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> 
> v2: fixed the style to follow both rST and kernel conventions (Ingo, Randy)
> 
>  Documentation/arch/x86/boot.rst | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)


Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

Thanks.

-- 
~Randy