RE: [ACPICA PATCH] Add CXL 3.0 structures (CXIMS & RDPAS) to the CEDT table

[Dan Williams <dan.j.williams@intel.com>]

alison.schofield@ wrote:
> From: Alison Schofield <alison.schofield@intel.com>
> 
> Prologue: The CXIMS addition to ACPICA was reverted, so, while I was
> at it, decided to collect both CEDT changes in one patch for ACPICA.
> Please review here, or on ACPICA github:
> https://github.com/acpica/acpica/pull/795
> Thanks,
> Alison
> 
> 
> The CXL 3.0 Specification[1] adds two new structures to
> the CXL Early Discovery Table (CEDT). The CEDT may include
> zero or more entries of these types:
> 
> CXIMS: CXL XOR Interleave Math Structure
>        Enables the host to find a targets position in an
>        Interleave Target List when XOR Math is used.
> 
> RDPAS: RCEC Downstream Post Association Structure
>        Enables the host to locate the Downstream Port(s)
>        that report errors to a given Root Complex Event
>        Collector (RCEC).
> 
> [1]https://www.computeexpresslink.org/spec-landing
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> ---
>  source/include/actbl1.h | 34 +++++++++++++++++++++++++++++++++-
>  1 file changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/source/include/actbl1.h b/source/include/actbl1.h
> index 3de78b0d8f01..6041e8f4c289 100644
> --- a/source/include/actbl1.h
> +++ b/source/include/actbl1.h
> @@ -525,7 +525,9 @@ enum AcpiCedtType
>  {
>      ACPI_CEDT_TYPE_CHBS                 = 0,
>      ACPI_CEDT_TYPE_CFMWS                = 1,
> -    ACPI_CEDT_TYPE_RESERVED             = 2,
> +    ACPI_CEDT_TYPE_CXIMS                = 2,
> +    ACPI_CEDT_TYPE_RDPAS                = 3,
> +    ACPI_CEDT_TYPE_RESERVED             = 4,
>  };
>  
>  /* Values for version field above */
> @@ -583,6 +585,7 @@ typedef struct acpi_cedt_cfmws_target_element
>  /* Values for Interleave Arithmetic field above */
>  
>  #define ACPI_CEDT_CFMWS_ARITHMETIC_MODULO   (0)
> +#define ACPI_CEDT_CFMWS_ARITHMETIC_XOR      (1)
>  
>  /* Values for Restrictions field above */
>  
> @@ -592,6 +595,35 @@ typedef struct acpi_cedt_cfmws_target_element
>  #define ACPI_CEDT_CFMWS_RESTRICT_PMEM       (1<<3)
>  #define ACPI_CEDT_CFMWS_RESTRICT_FIXED      (1<<4)
>  
> +/* 2: CXL XOR Interleave Math Structure */
> +
> +struct acpi_cedt_cxims {
> +    ACPI_CEDT_HEADER        Header;
> +    UINT16                  Reserved1;
> +    UINT8                   Hbig;
> +    UINT8                   NrXormaps;
> +    UINT64                  XormapList[];

This might be the source of the build trouble. I thought ACPICA builds
in constrained environments with simple compilers that do not support
variable-length arrays.

For example:

typedef struct acpi_table_slit
{
    ACPI_TABLE_HEADER       Header;             /* Common ACPI table header */
    UINT64                  LocalityCount;
    UINT8                   Entry[1];           /* Real size = localities^2 */

} ACPI_TABLE_SLIT;
https://github.com/acpica/acpica/blob/master/source/include/actbl3.h#L234


However, if this is the breakage then I don't understand why:

typedef struct acpi_cedt_cfmws
{
    ACPI_CEDT_HEADER        Header;
    UINT32                  Reserved1;
    UINT64                  BaseHpa;
    UINT64                  WindowSize;
    UINT8                   InterleaveWays;
    UINT8                   InterleaveArithmetic;
    UINT16                  Reserved2;
    UINT32                  Granularity;
    UINT16                  Restrictions;
    UINT16                  QtgId;
    UINT32                  InterleaveTargets[];

} ACPI_CEDT_CFMWS;
https://github.com/acpica/acpica/blob/master/source/include/actbl1.h#L561

Gets by without complaint?

Otherwise that's all I can see as the reason why the first attempt
reported build issues.

Bob, is there a place where someone can reproduce the ACPICA build
environment to check these issues themselves going forward?