linux-kernel - Re: [PATCH v2] efi: Unify dmi setup code over architectures arm/arm64, io64 and x86

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Message-ID: <CAKv+Gu9WwgYiiGp4sZOndD8znPxtg5g-qrSAvx9=zHm5x5ikSw@mail.gmail.com>
Date:   Thu, 21 Mar 2019 11:09:38 +0100
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Robert Richter <rrichter@...vell.com>
Cc:     Tony Luck <tony.luck@...el.com>, Fenghua Yu <fenghua.yu@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        "x86@...nel.org" <x86@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        Marcin Benka <mbenka@...vell.com>,
        "linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>
Subject: Re: [PATCH v2] efi: Unify dmi setup code over architectures
 arm/arm64, io64 and x86

On Thu, 21 Mar 2019 at 11:08, Robert Richter <rrichter@...vell.com> wrote:
>
> On 21.03.19 10:51:34, Ard Biesheuvel wrote:
> > On Thu, 21 Mar 2019 at 10:39, Robert Richter <rrichter@...vell.com> wrote:
> > >
> > > On 20.03.19 23:02:09, Ard Biesheuvel wrote:
> > > > On Wed, 20 Mar 2019 at 16:23, Robert Richter <rrichter@...vell.com> wrote:
> > > > >
> > > > > On 20.03.19 14:16:07, Robert Richter wrote:
> > > > > > On 20.03.19 13:05:37, Robert Richter wrote:
> > > > > > > @@ -167,6 +167,7 @@ static int __init arm_dmi_init(void)
> > > > > > >      * itself, depends on dmi_scan_machine() having been called already.
> > > > > > >      */
> > > > > > >     dmi_scan_machine();
> > > > > > > +   dmi_memdev_walk();
> > > > > > >     if (dmi_available)
> > > > > > >             dmi_set_dump_stack_arch_desc();
> > > > > > >     return 0;
> > > > > >
> > > > > > After
> > > > > >
> > > > > >  [PATCH] efi/arm: Show SMBIOS bank/device location in cper and
> > > > > >   ghes error logs
> > > > > >
> > > > > > wents in for arm/arm64, we can unify the code. See patch below.
> > > > >
> > > > > V2 with the fix in arm_dmi_init() below.
> > > > >
> > > > > -Robert
> > > > >
> > > > >
> > > > > -- >8 --
> > > > > From: Robert Richter <rrichter@...vell.com>
> > > > > Subject: [PATCH v2] efi: Unify dmi setup code over architectures arm/arm64,
> > > > >  io64 and x86
> > > > >
> > > > > All architectures (arm/arm64, io64 and x86) do the same here, so unify
> > > > > the code.
> > > > >
> > > > > Note: We do not need to call dump_stack_set_arch_desc() in case of
> > > > > !dmi_available. Both strings, dmi_ids_string and dump_stack_arch_
> > > > > desc_str are initialized zero and thus nothing would change.
> > > > >
> > > >
> > > > I don't understand the last sentence - we do not need to call
> > > > dump_stack_set_arch_desc() when !dmi_available, but we do so anyway,
> > > > right? Doesn't that wipe the arch description we set based on the DT
> > > > machine name?
> > >
> > > No, in dmi_setup() we exit early when !dmi_available. So for arm/arm64
> > > nothing changed. But for x86 and ia64 we no longer call dump_stack_
> > > set_arch_desc() in this case. This is ok since both strings,
> > > dmi_ids_string and dump_stack_arch_desc_str, are initialized zero and
> > > copying one to the other does not change anything.
> > >
> >
> > Ah, of course. Apologies for not reading more carefully.
> >
> > I'll take this patch via the EFI tree.
> >
> > It seems to me though that the previous patch makes the memdev_walk()
> > call unconditional for ARM, and this change subsequently makes it
> > dependent on dmi_available. Should we fix that?
>
> The first patch has the check in memdev_walk(). So that is looking
> good. The check is then moved to dmi_setup() in the 2nd patch.
>

OK, that works for me.

> Thanks for handling this.
>

Thanks for the contribution.