Re: [PATCH v1 1/1] DynamicTablesPkg: Add SMBIOS String table helper library

["Girish Mahadevan" <gmahadevan@nvidia.com>]

Hello Sami,

My apologies for the late response. I had one question/comment.

Comment marked with [GM] inline.

Best Regards
Girish

On 9/12/2022 8:18 AM, Sami Mujawar wrote:
> External email: Use caution opening links or attachments
> 
> 
> The Section 6.1.3, SMBIOS specification version 3.6.0 describes the
> handling of test strings in SMBIOS tables.
> 
> Test strings are added at the end of the formatted portion of the SMBIOS
> structure and are referenced by index in the SMBIOS structure.
> 
> Therefore, introduce a SmbiosStringTableLib to simplify the publishing
> of the string set.
> 
> SmbiosStringTableLib introduces a concept of string table which records
> the references to the SMBIOS strings as they are added and returns an
> string reference which is then assigned to the string field in the
> formatted portion of the SMBIOS structure. Once all strings are added,
> the library provides an interface to get the required size for the string
> set. This allows sufficient memory to be allocated for the SMBIOS table.
> The library also provides an interface to publish the string set in
> accordance with the SMBIOS specification.
> 
> Example:
> EFI_STATUS
> BuildSmbiosType17Table () {
>    STRING_TABLE         StrTable;
>    UINT8                DevLocatorRef;
>    UINT8                BankLocatorRef;
>    SMBIOS_TABLE_TYPE17  *SmbiosRecord;
>    CHAR8                *StringSet;
>    ...
> 
>    // Initialize string table for 7 strings
>    StringTableInitialize (&StrTable, 7);
> 
>    StringTableAddString (&StrTable, "SIMM 3", &DevLocatorRef);
>    StringTableAddString (&StrTable, "Bank 0", &BankLocatorRef);
>    ...
> 
>    SmbiosRecord = AllocateZeroPool (
>                     sizeof (SMBIOS_TABLE_TYPE17) +
>                       StringTableGetStringSetSize (&StrTable)
>                     );
>    ...
>    SmbiosRecord->DeviceLocator = DevLocatorRef;
>    SmbiosRecord->BankLocator = BankLocatorRef;
>    ...
>    // get the string set area
>    StringSet = (CHAR8*)(SmbiosRecord + 1);
> 
>    // publish the string set
>    StringTablePublishStringSet (
>      &StrTable,
>      StringSet,
>      StringTableGetStringSetSize (&StrTable)
>      );
> 
>    // free string table
>    StringTableFree (&StrTable);
> 
>    return EFI_SUCCESS;
> }
> 
> Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
> Cc: Alexei Fedorov <Alexei.Fedorov@arm.com>
> Cc: Pierre Gondois <pierre.gondois@arm.com>
> Cc: Girish Mahadevan <gmahadevan@nvidia.com>
> Cc: Jeff Brasen <jbrasen@nvidia.com>
> Cc: Ashish Singhal <ashishsingha@nvidia.com>
> Cc: Nick Ramirez <nramirez@nvidia.com>
> Cc: William Watson <wwatson@nvidia.com>
> Cc: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
> ---
> The changes can be seen at:
> https://github.com/samimujawar/edk2/tree/2370_smbios_stringlib_v1
> 
>   DynamicTablesPkg/DynamicTables.dsc.inc                                        |   3 +-
>   DynamicTablesPkg/DynamicTablesPkg.dec                                         |   5 +-
>   DynamicTablesPkg/DynamicTablesPkg.dsc                                         |   3 +-
>   DynamicTablesPkg/Include/Library/SmbiosStringTableLib.h                       | 119 ++++++++++
>   DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.c   | 227 ++++++++++++++++++++
>   DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.inf |  25 +++
>   6 files changed, 379 insertions(+), 3 deletions(-)
> 
> diff --git a/DynamicTablesPkg/DynamicTables.dsc.inc b/DynamicTablesPkg/DynamicTables.dsc.inc
> index 3d4fa0c4c4b67d6770aee8705c80cc18d20c823a..d35acc1788f2ddc5e2b5fc3e4bedfd48251f7ec8 100644
> --- a/DynamicTablesPkg/DynamicTables.dsc.inc
> +++ b/DynamicTablesPkg/DynamicTables.dsc.inc
> @@ -1,7 +1,7 @@
>   ## @file
>   #  Dsc include file for Dynamic Tables Framework.
>   #
> -#  Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.<BR>
> +#  Copyright (c) 2017 - 2022, Arm Limited. All rights reserved.<BR>
>   #
>   #  SPDX-License-Identifier: BSD-2-Clause-Patent
>   #
> @@ -18,6 +18,7 @@ [LibraryClasses.common]
>     SsdtPcieSupportLib|DynamicTablesPkg/Library/Common/SsdtPcieSupportLib/SsdtPcieSupportLib.inf
>     SsdtSerialPortFixupLib|DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf
>     TableHelperLib|DynamicTablesPkg/Library/Common/TableHelperLib/TableHelperLib.inf
> +  SmbiosStringTableLib|DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.inf
> 
>   [Components.common]
>     #
> diff --git a/DynamicTablesPkg/DynamicTablesPkg.dec b/DynamicTablesPkg/DynamicTablesPkg.dec
> index cc34c2bdd6ff9b5ca508961b3d0fe85ffbb73c12..2a79cfd4edebbdff05bee66fa01a17d68252e8a7 100644
> --- a/DynamicTablesPkg/DynamicTablesPkg.dec
> +++ b/DynamicTablesPkg/DynamicTablesPkg.dec
> @@ -1,7 +1,7 @@
>   ## @file
>   # dec file for Dynamic Tables Framework.
>   #
> -# Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.<BR>
> +# Copyright (c) 2017 - 2022, Arm Limited. All rights reserved.<BR>
>   #
>   # SPDX-License-Identifier: BSD-2-Clause-Patent
>   #
> @@ -39,6 +39,9 @@ [LibraryClasses]
>     ##  @libraryclass  Defines a set of helper methods.
>     TableHelperLib|Include/Library/TableHelperLib.h
> 
> +  ##  @libraryclass  Defines a set of SMBIOS string helper methods.
> +  SmbiosStringTableLib|Include/Library/SmbiosStringTableLib.h
> +
>   [Protocols]
>     # Configuration Manager Protocol GUID
>     gEdkiiConfigurationManagerProtocolGuid = { 0xd85a4835, 0x5a82, 0x4894, { 0xac, 0x2, 0x70, 0x6f, 0x43, 0xd5, 0x97, 0x8e } }
> diff --git a/DynamicTablesPkg/DynamicTablesPkg.dsc b/DynamicTablesPkg/DynamicTablesPkg.dsc
> index 07cc837552f587fe5bf9031e0061b0234e8698d4..bd5084a9008f040acdd16200ae8cdb23455ac101 100644
> --- a/DynamicTablesPkg/DynamicTablesPkg.dsc
> +++ b/DynamicTablesPkg/DynamicTablesPkg.dsc
> @@ -2,7 +2,7 @@
>   #  Dsc file for Dynamic Tables Framework.
>   #
>   #  Copyright (c) 2019, Linaro Limited. All rights reserved.<BR>
> -#  Copyright (c) 2019 - 2021, Arm Limited. All rights reserved.<BR>
> +#  Copyright (c) 2019 - 2022, Arm Limited. All rights reserved.<BR>
>   #
>   #  SPDX-License-Identifier: BSD-2-Clause-Patent
>   #
> @@ -46,6 +46,7 @@ [Components.common]
>     DynamicTablesPkg/Library/Common/TableHelperLib/TableHelperLib.inf
>     DynamicTablesPkg/Library/FdtHwInfoParserLib/FdtHwInfoParserLib.inf
>     DynamicTablesPkg/Library/Common/DynamicPlatRepoLib/DynamicPlatRepoLib.inf
> +  DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.inf
> 
>   [BuildOptions]
>     *_*_*_CC_FLAGS = -D DISABLE_NEW_DEPRECATED_INTERFACES
> diff --git a/DynamicTablesPkg/Include/Library/SmbiosStringTableLib.h b/DynamicTablesPkg/Include/Library/SmbiosStringTableLib.h
> new file mode 100644
> index 0000000000000000000000000000000000000000..246d4d30ddf901640ea720c108e2971552ec6c96
> --- /dev/null
> +++ b/DynamicTablesPkg/Include/Library/SmbiosStringTableLib.h
> @@ -0,0 +1,119 @@
> +/** @file
> +  SMBIOS String Table Helper library.
> +
> +  Copyright (c) 2022, Arm Limited. All rights reserved.<BR>
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +**/
> +
> +#ifndef SMBIOS_STRING_TABLE_H_
> +#define SMBIOS_STRING_TABLE_H_
> +
> +/** A structure representing a string in the string table.
> +*/
> +typedef struct StringElement {
> +  /// Length of the string (does not include the NULL termination)
> +  UINTN          StringLen;
> +
> +  /// Reference to the string
> +  CONST CHAR8    *String;
> +} STRING_ELEMENT;
> +
> +/** A structure representing a string table.
> +*/
> +typedef struct StringTable {
> +  /// Count of strings in the table
> +  UINT8             StrCount;
> +
> +  /// Total length of all strings in the table (does not include
> +  // the NULL termination for each string)
> +  UINTN             TotalStrLen;
> +
> +  /// Maximum string count
> +  UINT8             MaxStringElements;
> +
> +  /// Pointer to the string table elements
> +  STRING_ELEMENT    *Elements;
> +} STRING_TABLE;
> +
> +/** Add a string to the string table
> +
> +  @param [IN]   StrTable  Pointer to the string table
> +  @param [IN]   Str       Pointer to the string
> +  @param [OUT]  StrRef    Optional pointer to retrieve the string field
> +                          reference of the string in the string table
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer
> +  @return EFI_BUFFER_TOO_SMALL   Insufficient space to add string
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTableAddString (
> +  IN        STRING_TABLE *CONST  StrTable,
> +  IN  CONST CHAR8                *Str,
> +  OUT       UINT8                *StrRef      OPTIONAL
> +  );
> +
> +/** Returns the total size required to publish the strings to the SMBIOS
> +    string area.
> +
> +  @param [IN] StrTable              Pointer to the string table
> +
> +  @return Total size required to publish the strings in the SMBIOS string area.
> +**/
> +UINTN
> +EFIAPI
> +StringTableGetStringSetSize (
> +  IN  STRING_TABLE *CONST  StrTable
> +  );
> +
> +/** Iterate through the string table and publish the strings in the SMBIOS
> +    string area.
> +
> +  @param [IN] StrTable              Pointer to the string table
> +  @param [IN] SmbiosStringAreaStart Start address of the SMBIOS string area.
> +  @param [IN] SmbiosStringAreaSize  Size of the SMBIOS string area.
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer
> +  @return EFI_BUFFER_TOO_SMALL   Insufficient space to publish strings
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTablePublishStringSet (
> +  IN        STRING_TABLE  *CONST  StrTable,
> +  IN        CHAR8         *CONST  SmbiosStringAreaStart,
> +  IN  CONST UINTN                 SmbiosStringAreaSize
> +  );
> +
> +/** Initialise the string table and allocate memory for the string elements.
> +
> +  @param [IN] StrTable           Pointer to the string table
> +  @param [IN] MaxStringElements  Maximum number of strings that the string
> +                                 table can hold.
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer
> +  @return EFI_OUT_OF_RESOURCES   Failed to allocate memory for string elements
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTableInitialize (
> +  IN STRING_TABLE *CONST  StrTable,
> +  IN UINTN                MaxStringElements
> +  );
> +
> +/** Free memory allocated for the string elements in the string table.
> +
> +  @param [IN] StrTable           Pointer to the string table
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer or string elements
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTableFree (
> +  IN STRING_TABLE *CONST  StrTable
> +  );
> +
> +#endif // SMBIOS_STRING_TABLE_H_
> diff --git a/DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.c b/DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..bd186f27fe1613cf819b6600e62960c003a796d6
> --- /dev/null
> +++ b/DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.c
> @@ -0,0 +1,227 @@
> +/** @file
> +  SMBIOS String Table Helper
> +
> +  Copyright (c) 2022, Arm Limited. All rights reserved.<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +  @par Reference(s):
> +  - DSP0134 - SMBIOS Specification Version 3.6.0, 2022-06-17
> +**/
> +
> +#include <Library/BaseLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/SmbiosStringTableLib.h>
> +
> +/** Add a string to the string table
> +
> +  @param [IN]   StrTable  Pointer to the string table
> +  @param [IN]   Str       Pointer to the string
> +  @param [OUT]  StrRef    Optional pointer to retrieve the string field
> +                          reference of the string in the string table
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer
> +  @return EFI_BUFFER_TOO_SMALL   Insufficient space to add string
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTableAddString (
> +  IN        STRING_TABLE *CONST  StrTable,
> +  IN  CONST CHAR8                *Str,
> +  OUT       UINT8                *StrRef      OPTIONAL
> +  )
> +{
> +  UINTN           StrLength;
> +  STRING_ELEMENT  *StrElement;
> +
> +  if ((StrTable == NULL) || (Str == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (StrTable->StrCount >= StrTable->MaxStringElements) {
> +    return EFI_BUFFER_TOO_SMALL;
> +  }
> +
> +  StrLength = AsciiStrLen (Str);
> +  if (StrLength == 0) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  // Update the string element
> +  StrElement            = &StrTable->Elements[StrTable->StrCount];
> +  StrElement->StringLen = StrLength;
> +  StrElement->String    = Str;
> +
> +  // Update String table information
> +  StrTable->TotalStrLen += StrLength;
> +  StrTable->StrCount++;
> +
> +  // Return the index of the string in the string table if requested
> +  if (StrRef != NULL) {
> +    // Note: SMBIOS string field references start at 1. So, return the
> +    // StrCount as the string refrence after it is updated.
> +    *StrRef = StrTable->StrCount;
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/** Returns the total size required to publish the strings to the SMBIOS
> +    string area.
> +
> +  @param [IN] StrTable              Pointer to the string table
> +
> +  @return Total size required to publish the strings in the SMBIOS string area.
> +**/
> +UINTN
> +EFIAPI
> +StringTableGetStringSetSize (
> +  IN  STRING_TABLE *CONST  StrTable
> +  )
> +{
> +  if (StrTable == NULL) {
> +    ASSERT (0);
> +    return 0;
> +  }
> +
> +  // See Section 6.1.3 Text strings, SMBIOS Specification Version 3.6.0
> +  // - If the formatted portion of the structure contains string-reference
> +  //   fields and all the string fields are set to 0 (no string references),
> +  //   the formatted section of the structure is followed by two null (00h)
> +  //   BYTES.
> +  // - Each string is terminated with a null (00h) BYTE
> +  // - and the set of strings is terminated with an additional null (00h) BYTE.
> +
> +  // Therefore, if string count = 0, return 2
> +  // if string count > 0, the string set size =
> +  // StrTable->TotalStrLen (total length of the strings in the string table)
> +  // + StrTable->StrCount (add string count to include '\0' for each string)
> +  // +1 (an additional '\0' is required at the end of the string set).
> +  return (StrTable->StrCount == 0) ? 2 :
> +         (StrTable->TotalStrLen + StrTable->StrCount + 1);
> +}
> +
> +/** Iterate through the string table and publish the strings in the SMBIOS
> +    string area.
> +
> +  @param [IN] StrTable              Pointer to the string table
> +  @param [IN] SmbiosStringAreaStart Start address of the SMBIOS string area.
> +  @param [IN] SmbiosStringAreaSize  Size of the SMBIOS string area.
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer
> +  @return EFI_BUFFER_TOO_SMALL   Insufficient space to publish strings
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTablePublishStringSet (
> +  IN        STRING_TABLE  *CONST  StrTable,
> +  IN        CHAR8         *CONST  SmbiosStringAreaStart,
> +  IN  CONST UINTN                 SmbiosStringAreaSize
> +  )
> +{
> +  UINT8           Index;
> +  STRING_ELEMENT  *StrElement;
> +  CHAR8           *SmbiosString;
> +  UINTN           BytesRemaining;
> +  UINTN           BytesCopied;
> +
> +  if ((StrTable == NULL) || (SmbiosStringAreaStart == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (SmbiosStringAreaSize < StringTableGetStringSetSize (StrTable)) {
> +    return EFI_BUFFER_TOO_SMALL;
> +  }
> +
> +  SmbiosString   = SmbiosStringAreaStart;
> +  BytesRemaining = SmbiosStringAreaSize;
> +
> +  if (StrTable->StrCount == 0) {
> +    // See Section 6.1.3 Text strings, SMBIOS Specification Version 3.6.0
> +    // If the formatted portion of the structure contains string-reference
> +    // fields and all the string fields are set to 0 (no string references),
> +    // the formatted section of the structure is followed by two null (00h)
> +    // BYTES.
> +    *SmbiosString++ = '\0';
> +  } else {
> +    for (Index = 0; Index < StrTable->StrCount; Index++) {
> +      StrElement = &StrTable->Elements[Index];
> +      AsciiStrCpyS (SmbiosString, BytesRemaining, StrElement->String);
> +
> +      // See Section 6.1.3 Text strings, SMBIOS Specification Version 3.6.0
> +      // - Each string is terminated with a null (00h) BYTE
> +      // Bytes Copied = String length + 1 for the string NULL terminator.
> +      BytesCopied     = StrElement->StringLen + 1;
> +      BytesRemaining -= BytesCopied;
> +      SmbiosString   += BytesCopied;
> +    }
> +  }
> +
> +  // See Section 6.1.3 Text strings, SMBIOS Specification Version 3.6.0
> +  // - the set of strings is terminated with an additional null (00h) BYTE.
> +  *SmbiosString = '\0';
[GM] Shouldn't you advance the SmbiosString pointer by one more ? After 
the loop isn't SmbiosString going to be at the NULL char of the last 
string ? And we're trying to add one more NULL character ?
Should it be:
SmbiosString++;
*SmbiosString = '\0';


> +  return EFI_SUCCESS;
> +}
> +
> +/** Initialise the string table and allocate memory for the string elements.
> +
> +  @param [IN] StrTable           Pointer to the string table
> +  @param [IN] MaxStringElements  Maximum number of strings that the string
> +                                 table can hold.
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer
> +  @return EFI_OUT_OF_RESOURCES   Failed to allocate memory for string elements
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTableInitialize (
> +  IN STRING_TABLE *CONST  StrTable,
> +  IN UINTN                MaxStringElements
> +  )
> +{
> +  STRING_ELEMENT  *Elements;
> +
> +  if ((StrTable == NULL) || (MaxStringElements > MAX_UINT8)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  ZeroMem (StrTable, sizeof (STRING_TABLE));
> +
> +  Elements = (STRING_ELEMENT *)AllocateZeroPool (
> +                                 sizeof (STRING_ELEMENT) * MaxStringElements
> +                                 );
> +  if (Elements == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  StrTable->Elements          = Elements;
> +  StrTable->MaxStringElements = (UINT8)MaxStringElements;
> +  return EFI_SUCCESS;
> +}
> +
> +/** Free memory allocated for the string elements in the string table.
> +
> +  @param [IN] StrTable           Pointer to the string table
> +
> +  @return EFI_SUCCESS            Success
> +  @return EFI_INVALID_PARAMETER  Invalid string table pointer or string elements
> +**/
> +EFI_STATUS
> +EFIAPI
> +StringTableFree (
> +  IN STRING_TABLE *CONST  StrTable
> +  )
> +{
> +  if ((StrTable == NULL) || (StrTable->Elements == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  FreePool (StrTable->Elements);
> +  ZeroMem (StrTable, sizeof (STRING_TABLE));
> +  return EFI_SUCCESS;
> +}
> diff --git a/DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.inf b/DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.inf
> new file mode 100644
> index 0000000000000000000000000000000000000000..88624c50e3f3e930074222b6d686f75485538b26
> --- /dev/null
> +++ b/DynamicTablesPkg/Library/Common/SmbiosStringTableLib/SmbiosStringTableLib.inf
> @@ -0,0 +1,25 @@
> +## @file
> +#  SMBIOS String Table Helper library.
> +#
> +#  Copyright (c) 2022, Arm Limited. All rights reserved.
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +##
> +
> +[Defines]
> +  INF_VERSION    = 0x0001001B
> +  BASE_NAME      = SmbiosStringTableLib
> +  FILE_GUID      = 8C570DD8-531E-473F-85C6-9252746DBAC1
> +  VERSION_STRING = 1.0
> +  MODULE_TYPE    = DXE_DRIVER
> +  LIBRARY_CLASS  = SmbiosStringTableLib
> +
> +[Sources]
> +  SmbiosStringTableLib.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  DynamicTablesPkg/DynamicTablesPkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> --
> 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
>