Re: [PATCH v2 RESEND 05/18] x86, ACPICA: Split acpi_boot_table_init() into two parts.

[Rafael J. Wysocki]

On Friday, August 02, 2013 05:14:24 PM Tang Chen wrote:
> In ACPI, SRAT(System Resource Affinity Table) contains NUMA info.
> The memory affinities in SRAT record every memory range in the
> system, and also, flags specifying if the memory range is
> hotpluggable.
> (Please refer to ACPI spec 5.0 5.2.16)
> 
> memblock starts to work at very early time, and SRAT has not been
> parsed. So we don't know which memory is hotpluggable. In order
> to use memblock to reserve hotpluggable memory, we need to obtain
> SRAT memory affinity info earlier.
> 
> In the current acpi_boot_table_init(), it does the following:
> 1. Parse RSDT, so that we can find all the tables.
> 2. Initialize acpi_gbl_root_table_list, an array of acpi table
>    descriptors used to store each table's address, length, signature,
>    and so on.
> 3. Check if there is any table in initrd intending to override
>    tables from firmware. If so, override the firmware tables.
> 4. Initialize all the data in acpi_gbl_root_table_list.
> 
> In order to parse SRAT at early time, we need to do similar job as
> step 1 and 2 above earlier to obtain SRAT. It will be very convenient
> if we have acpi_gbl_root_table_list initialized. We can use address
> and signature to find SRAT.
> 
> Since step 1 and 2 allocates no memory, it is OK to do these two
> steps earlier.
> 
> But step 3 will check acpi initrd table override, not just SRAT,
> but also all the other tables. So it is better to keep it untouched.
> 
> This patch splits acpi_boot_table_init() into two steps:
> 1. Parse RSDT, which cannot be overrided, and initialize
>    acpi_gbl_root_table_list. (step 1 + 2 above)
> 2. Install all ACPI tables into acpi_gbl_root_table_list.
>    (step 3 + 4 above)
> 
> In later patches, we will do step 1 + 2 earlier.

Please note that Linux is not the only user of the code you're modifying, so
you need to make it possible to use the existing functions.

In particular, acpi_tb_parse_root_table() can't be modified the way you did it,
because that would require all of the users of ACPICA to be modified.

> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> Reviewed-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
> ---
>  drivers/acpi/acpica/tbutils.c |   25 ++++++++++++++++++++++---
>  drivers/acpi/tables.c         |    2 ++
>  include/acpi/acpixf.h         |    2 ++
>  3 files changed, 26 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
> index bffdfc7..e3621cf 100644
> --- a/drivers/acpi/acpica/tbutils.c
> +++ b/drivers/acpi/acpica/tbutils.c
> @@ -577,9 +577,30 @@ acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
>  	 */
>  	acpi_os_unmap_memory(table, length);
>  
> +	return_ACPI_STATUS(AE_OK);
> +}
> +
> +/*******************************************************************************
> + *
> + * FUNCTION:    acpi_tb_install_root_table
> + *
> + * DESCRIPTION: This function installs all the ACPI tables in RSDT into
> + *              acpi_gbl_root_table_list.
> + *
> + ******************************************************************************/
> +
> +void __init
> +acpi_tb_install_root_table()
> +{
> +	int i;
> +
>  	/*
>  	 * Complete the initialization of the root table array by examining
> -	 * the header of each table
> +	 * the header of each table.
> +	 *
> +	 * First two entries in the table array are reserved for the DSDT
> +	 * and FACS, which are not actually present in the RSDT/XSDT - they
> +	 * come from the FADT.
>  	 */
>  	for (i = 2; i < acpi_gbl_root_table_list.current_table_count; i++) {
>  		acpi_tb_install_table(acpi_gbl_root_table_list.tables[i].
> @@ -593,6 +614,4 @@ acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
>  			acpi_tb_parse_fadt(i);
>  		}
>  	}
> -
> -	return_ACPI_STATUS(AE_OK);
>  }
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index d67a1fe..8860e79 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -353,6 +353,8 @@ int __init acpi_table_init(void)
>  	if (ACPI_FAILURE(status))
>  		return 1;
>  
> +	acpi_tb_install_root_table();
> +
>  	check_multiple_madt();
>  	return 0;
>  }
> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
> index 22d497e..e9c9b88 100644
> --- a/include/acpi/acpixf.h
> +++ b/include/acpi/acpixf.h
> @@ -118,6 +118,8 @@ acpi_status
>  acpi_initialize_tables(struct acpi_table_desc *initial_storage,
>  		       u32 initial_table_count, u8 allow_resize);
>  
> +void acpi_tb_install_root_table(void);
> +
>  acpi_status __init acpi_initialize_subsystem(void);
>  
>  acpi_status acpi_enable_subsystem(u32 flags);
> 

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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