[PATCH] smbios: arm64: Allow table to be written at a fixed addr

[Heinrich Schuchardt]

Am 25. Oktober 2023 01:28:10 MESZ schrieb Simon Glass <sjg at chromium.org>:
>Hi Tom,
>
>On Tue, 24 Oct 2023 at 15:34, Tom Rini <trini at konsulko.com> wrote:
>>
>> On Mon, Oct 23, 2023 at 05:31:19PM +0200, Mark Kettenis wrote:
>> > > From: Simon Glass <sjg at chromium.org>
>> > > Date: Mon, 23 Oct 2023 00:04:14 -0700
>> > >
>> > > Hi Caleb,
>> > >
>> > > On Sat, 21 Oct 2023 at 01:43, Caleb Connolly <caleb.connolly at linaro.org> wrote:
>> > > >
>> > > > Hi Simon,
>> > > >
>> > > > On 21/10/2023 01:45, Simon Glass wrote:
>> > > > > U-Boot typically sets up its malloc() pool near the top of memory. On
>> > > > > ARM64 systems this can result in an SMBIOS table above 4GB which is
>> > > > > not supported by SMBIOSv2.
>> [snip]
>> > There is absolutely no guarantee that arm64 machines have memory below
>> > 4GB.  Examples of SoCs that have no memory below 4GB are AMD's Opteron
>> > A1100 SoC and all the recent Apple SoCs.
>>
>> So one thing to resolve here is where does that requirement about the
>> SMBIOS table needing to be below 4GB come from (standards wise), and in
>> turn is that obeyed by consumers like say Linux or OpenBSD? Answering my
>> own question, maybe in part, https://www.dmtf.org/standards/smbios reads
>> to me like there's a v3 and maybe we should be doing what we need to
>> support / identify as that, if it doesn't have that restriction?
>
>Yes that was my previous patch. However 1) we apparently don't want to
>use SMBIOS3 and 2) my patch had some sort of bug so that it wasn't
>read correctly.
>
>So my next version is going to be along the lines of what was discussed here.
>
>Of course, we cannot solve Mark's problem with SMBIOS2, but I suppose
>that is obvious. Anyway, those platforms probably don't need SMBIOS.

You are heading in the wrong direction. We need SMBIOS 3. SMBIOS 2 is only a fallback for outdated tools.

Upcoming mainline RISC-V platforms will also have memory starting above 4GiB.

Best regards

Heinrich

>
>Regards,
>Simon