linux-kernel - Re: [PATCH v3 3/7] acpi/ghes: Support GPIO error source.

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Message-ID: <20240801145637.03c34fd3@foz.lan>
Date: Thu, 1 Aug 2024 14:56:37 +0200
From: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To: Igor Mammedov <imammedo@...hat.com>, Jonathan Cameron
 <Jonathan.Cameron@...wei.com>
Cc: Shiju Jose <shiju.jose@...wei.com>, "Michael S. Tsirkin"
 <mst@...hat.com>, Ani Sinha <anisinha@...hat.com>, Dongjiu Geng
 <gengdongjiu1@...il.com>, linux-kernel@...r.kernel.org,
 qemu-arm@...gnu.org, qemu-devel@...gnu.org
Subject: Re: [PATCH v3 3/7] acpi/ghes: Support GPIO error source.

Em Tue, 30 Jul 2024 10:40:28 +0200
Igor Mammedov <imammedo@...hat.com> escreveu:

> > diff --git a/include/hw/acpi/ghes.h b/include/hw/acpi/ghes.h
> > index 674f6958e905..4f1ab1a73a06 100644
> > --- a/include/hw/acpi/ghes.h
> > +++ b/include/hw/acpi/ghes.h
> > @@ -58,6 +58,7 @@ enum AcpiGhesNotifyType {
> >  
> >  enum {
> >      ACPI_HEST_SRC_ID_SEA = 0,
> > +    ACPI_HEST_SRC_ID_GPIO = 1,  
> is it defined by some spec, or just a made up number?

I don't know. Maybe Jonathan or Shiju knows better, as the original patch
came from them, but I didn't find any parts of the ACPI spec defining the
values for source ID.

Checking at build_ghes_v2() implementation, this is used on two places:

1. as GHESv2 source ID:
    /*
     * Type:
     * Generic Hardware Error Source version 2(GHESv2 - Type 10)
     */
    build_append_int_noprefix(table_data, ACPI_GHES_SOURCE_GENERIC_ERROR_V2, 2);
    /* Source Id */
    build_append_int_noprefix(table_data, source_id, 2);
    /* Related Source Id */
    build_append_int_noprefix(table_data, 0xffff, 2);

as an address offset:

    address_offset = table_data->len;
    /* Error Status Address */
    build_append_gas(table_data, AML_AS_SYSTEM_MEMORY, 0x40, 0,
                     4 /* QWord access */, 0);
    bios_linker_loader_add_pointer(linker, ACPI_BUILD_TABLE_FILE,
        address_offset + GAS_ADDR_OFFSET, sizeof(uint64_t),
        ACPI_GHES_ERRORS_FW_CFG_FILE, source_id * sizeof(uint64_t));

So, if I had to guess, I'd say that this was made up, in a way that
the size of the table will fit just two sources, starting from zero.

So, I'll change the code to just:

	enum {
            ACPI_HEST_SRC_ID_SEA = 0,
            ACPI_HEST_SRC_ID_GPIO, 
	    /* future ids go here */
	    ACPI_HEST_SRC_ID_RESERVED,
	};

To remove the false impression that this could be originated from the
spec.

Thanks,
Mauro