linux-kernel - Re: [PATCH v2 1/2] ACPICA: Detect FACS in reduced hardware build

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Message-ID: <CAJZ5v0hPtvVRM=Te2oPzCvE3tOy_rXYGJwaoQOfNc71z+pmkvA@mail.gmail.com>
Date: Tue, 20 Aug 2024 16:55:40 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Jiaqing Zhao <jiaqing.zhao@...ux.intel.com>
Cc: Robert Moore <robert.moore@...el.com>, 
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>, Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org, 
	acpica-devel@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] ACPICA: Detect FACS in reduced hardware build

On Mon, Aug 12, 2024 at 7:47 AM Jiaqing Zhao
<jiaqing.zhao@...ux.intel.com> wrote:
>
> According to Section 5.2.10 of ACPI Specification, FACS is optional
> in reduced hardware model. Enable the detection for "Hardware-reduced
> ACPI support only" build (CONFIG_ACPI_REDUCED_HARDWARE_ONLY=y) also.
>
> Link: https://github.com/acpica/acpica/commit/ee53ed6b5452612bb44af542b68d605f8b2b1104
> Signed-off-by: Jiaqing Zhao <jiaqing.zhao@...ux.intel.com>
> ---
>  drivers/acpi/acpica/acglobal.h |  6 +-----
>  drivers/acpi/acpica/tbutils.c  |  5 +----
>  drivers/acpi/acpica/utxfinit.c | 24 ++++++++++++------------
>  include/acpi/acconfig.h        |  1 -
>  4 files changed, 14 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/acpi/acpica/acglobal.h b/drivers/acpi/acpica/acglobal.h
> index f4c90fc99be2..309ce8efb4f6 100644
> --- a/drivers/acpi/acpica/acglobal.h
> +++ b/drivers/acpi/acpica/acglobal.h
> @@ -29,11 +29,7 @@ ACPI_INIT_GLOBAL(u32, acpi_gbl_dsdt_index, ACPI_INVALID_TABLE_INDEX);
>  ACPI_INIT_GLOBAL(u32, acpi_gbl_facs_index, ACPI_INVALID_TABLE_INDEX);
>  ACPI_INIT_GLOBAL(u32, acpi_gbl_xfacs_index, ACPI_INVALID_TABLE_INDEX);
>  ACPI_INIT_GLOBAL(u32, acpi_gbl_fadt_index, ACPI_INVALID_TABLE_INDEX);
> -
> -#if (!ACPI_REDUCED_HARDWARE)
> -ACPI_GLOBAL(struct acpi_table_facs *, acpi_gbl_FACS);
> -
> -#endif                         /* !ACPI_REDUCED_HARDWARE */
> +ACPI_INIT_GLOBAL(struct acpi_table_facs *, acpi_gbl_FACS, NULL);
>
>  /* These addresses are calculated from the FADT Event Block addresses */
>
> diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
> index 15fa68a5ea6e..356700349b45 100644
> --- a/drivers/acpi/acpica/tbutils.c
> +++ b/drivers/acpi/acpica/tbutils.c
> @@ -18,7 +18,6 @@ ACPI_MODULE_NAME("tbutils")
>  static acpi_physical_address
>  acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size);
>
> -#if (!ACPI_REDUCED_HARDWARE)
>  /*******************************************************************************
>   *
>   * FUNCTION:    acpi_tb_initialize_facs
> @@ -37,8 +36,7 @@ acpi_status acpi_tb_initialize_facs(void)
>         struct acpi_table_facs *facs;
>
>         if (acpi_gbl_FADT.Xfacs &&
> -                  (!acpi_gbl_FADT.facs
> -                   || !acpi_gbl_use32_bit_facs_addresses)) {
> +           (!acpi_gbl_FADT.facs || !acpi_gbl_use32_bit_facs_addresses)) {
>                 (void)acpi_get_table_by_index(acpi_gbl_xfacs_index,
>                                               ACPI_CAST_INDIRECT_PTR(struct
>                                                                      acpi_table_header,

I'm not sure how this change is related to the rest of the patch.

It doesn't appear to be present in the original commit pointed to by
the Link tag.

> @@ -56,7 +54,6 @@ acpi_status acpi_tb_initialize_facs(void)
>
>         return (AE_OK);
>  }
> -#endif                         /* !ACPI_REDUCED_HARDWARE */
>
>  /*******************************************************************************
>   *
> diff --git a/drivers/acpi/acpica/utxfinit.c b/drivers/acpi/acpica/utxfinit.c
> index 1915bec2b279..70ae0afa7939 100644
> --- a/drivers/acpi/acpica/utxfinit.c
> +++ b/drivers/acpi/acpica/utxfinit.c
> @@ -120,6 +120,18 @@ acpi_status ACPI_INIT_FUNCTION acpi_enable_subsystem(u32 flags)
>          */
>         acpi_gbl_early_initialization = FALSE;
>
> +       /*
> +        * Obtain a permanent mapping for the FACS. This is required for the
> +        * Global Lock and the Firmware Waking Vector
> +        */
> +       if (!(flags & ACPI_NO_FACS_INIT)) {
> +               status = acpi_tb_initialize_facs();
> +               if (ACPI_FAILURE(status)) {
> +                       ACPI_WARNING((AE_INFO, "Could not map the FACS table"));
> +                       return_ACPI_STATUS(status);
> +               }
> +       }
> +
>  #if (!ACPI_REDUCED_HARDWARE)
>
>         /* Enable ACPI mode */
> @@ -137,18 +149,6 @@ acpi_status ACPI_INIT_FUNCTION acpi_enable_subsystem(u32 flags)
>                 }
>         }
>
> -       /*
> -        * Obtain a permanent mapping for the FACS. This is required for the
> -        * Global Lock and the Firmware Waking Vector
> -        */
> -       if (!(flags & ACPI_NO_FACS_INIT)) {
> -               status = acpi_tb_initialize_facs();
> -               if (ACPI_FAILURE(status)) {
> -                       ACPI_WARNING((AE_INFO, "Could not map the FACS table"));
> -                       return_ACPI_STATUS(status);
> -               }
> -       }
> -
>         /*
>          * Initialize ACPI Event handling (Fixed and General Purpose)
>          *
> diff --git a/include/acpi/acconfig.h b/include/acpi/acconfig.h
> index d768d9c568cf..2da5f4a6e814 100644
> --- a/include/acpi/acconfig.h
> +++ b/include/acpi/acconfig.h
> @@ -67,7 +67,6 @@
>   *      General Purpose Events (GPEs)
>   *      Global Lock
>   *      ACPI PM timer
> - *      FACS table (Waking vectors and Global Lock)
>   */
>  #ifndef ACPI_REDUCED_HARDWARE
>  #define ACPI_REDUCED_HARDWARE           FALSE
> --
> 2.43.0
>
>