[PATCH v2 01/16] x86: Update the bootparam header

[Bin Meng]

Hi Andy,

On Tue, Sep 8, 2020 at 10:06 PM Andy Shevchenko
<andriy.shevchenko at linux.intel.com> wrote:
>
> On Tue, Sep 01, 2020 at 04:23:45PM +0800, Bin Meng wrote:
> > On Sun, Aug 30, 2020 at 5:42 AM Simon Glass <sjg at chromium.org> wrote:
> > >
> > > This header is missing a few of the newer features from the specification.
> > > Add these as well as a link to the spec. Also use the BIT() macros where
> > > appropriate.
>
> > > +/**
> > > + * struct setup_header - Information needed by Linux to boot
> > > + *
> > > + * See https://www.kernel.org/doc/html/latest/x86/boot.html
> >
> > Now I am confused. This kernel document says:
> >
> > Protocol 2.14 BURNT BY INCORRECT COMMIT
> > ae7e1238e68f2a472a125673ab506d49158c1889 (x86/boot: Add ACPI RSDP
> > address to setup_header) DO NOT USE!!! ASSUME SAME AS 2.13.
>
> Where did you get this "DO NOT USE!!! ASSUME SAME AS 2.13" from?

Please see:
https://www.kernel.org/doc/html/latest/x86/boot.html

Chapter "1. The Linux/x86 Boot Protocol"

Protocol 2.14 BURNT BY INCORRECT COMMIT
ae7e1238e68f2a472a125673ab506d49158c1889 (x86/boot: Add ACPI RSDP
address to setup_header) DO NOT USE!!! ASSUME SAME AS 2.13.

>
>
> > However in U-Boot there was a commit from Andy saying that:
> >
> > commit d905aa8a4277e200e11fdf6d73a7c76d0e6f34a4 (<=== U-Boot commit)
> > Author: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> > Date:   Fri Sep 13 18:42:00 2019 +0300
> >
> >     x86: zImage: Propagate acpi_rsdp_addr to kernel via boot parameters
> >
> > ...
> >
> >     after upstream got eventually the Linux kernel
> >
> >     commit e6e094e053af75cbc164e950814d3d084fb1e698
> >     Author: Juergen Gross <jgross at suse.com>
> >     Date:   Tue Nov 20 08:25:29 2018 +0100
> >
> >         x86/acpi, x86/boot: Take RSDP address from boot params if available
> >
> > So there are 2 commits in the Linux kernel that do the same thing, one
> > in boot_params, the other one in setup_header?
>
> I think this
> 384184044981 ("x86/boot: Mostly revert commit ae7e1238e68f2a ("Add ACPI RSDP address to setup_header")")
> explains what happened.

Thanks for the info.

>
> > e6e094e053af75cbc164e950814d3d084fb1e698 : x86/acpi, x86/boot: Take
> > RSDP address from boot params if available
> > ae7e1238e68f2a472a125673ab506d49158c1889 : x86/boot: Add ACPI RSDP
> > address to setup_header
> >

Regards,
Bin