[edk2-devel] [PATCH v4 1/2] ShellPkg/AcpiView: Adds ACPI_PARSER bitfield parser
Sami Mujawar
sami.mujawar at arm.com
Wed Jan 19 16:44:11 UTC 2022
Hi Abdul,
Thank you for providing a patch to add this feature to Acpiview.
I have some minor feedback marked inline as [SAMI].
Regards,
Sami Mujawar
On 19/12/2021 02:44 PM, Abdul Lateef Attar wrote:
> Adds ParseAcpiBitFields() which is based on
> ParseAcpi() and capable of parsing the bit fields.
> Supports parsing of UINT8, UINT16, UINT32 and UINT64 byte data.
>
> Cc: Ray Ni <ray.ni at intel.com>
> Cc: Zhichao Gao <zhichao.gao at intel.com>
> Cc: Sami Mujawar <sami.mujawar at arm.com>
> Signed-off-by: Abdul Lateef Attar <abdattar at amd.com>
> ---
> ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h | 45 +++++
> ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c | 185 ++++++++++++++++++++
> 2 files changed, 230 insertions(+)
>
> diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
> index 5c916a4720b8..83266e8ec2d3 100644
> --- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
> @@ -2,6 +2,7 @@
> Header file for ACPI parser
>
>
>
> Copyright (c) 2016 - 2020, Arm Limited. All rights reserved.
>
> + Copyright (c) 2021, AMD Incorporated. All rights reserved.
>
> SPDX-License-Identifier: BSD-2-Clause-Patent
>
> **/
>
>
>
> @@ -251,6 +252,11 @@ typedef VOID (EFIAPI *FNPTR_FIELD_VALIDATOR)(UINT8 *Ptr, VOID *Context);
> the field data. If the field is more complex and requires additional
>
> processing for formatting and representation a print formatter function
>
> can be specified in 'PrintFormatter'.
>
> +
>
> + ParseAcpiBitFields() uses AcpiParser structure to parse the bit fields.
>
> + It considers Length as a number of bits that need to be parsed.
>
> + Also, the Offset field will be considered as starting offset of the bitfield.
>
> +
>
> The PrintFormatter function may choose to use the format string
>
> specified by 'Format' or use its own internal format string.
>
>
>
> @@ -264,10 +270,12 @@ typedef struct AcpiParser {
>
>
> /// The length of the field.
>
> /// (Byte Length column from ACPI table spec)
>
> + /// Length(in bits) of the bitfield if used with ParseAcpiBitFields().
>
> UINT32 Length;
>
>
>
> /// The offset of the field from the start of the table.
>
> /// (Byte Offset column from ACPI table spec)
>
> + /// The Bit offset of the field if used with ParseAcpiBitFields().
>
> UINT32 Offset;
>
>
>
> /// Optional Print() style format string for tracing the data. If not
>
> @@ -364,6 +372,43 @@ ParseAcpi (
> IN UINT32 ParserItems
>
> );
>
>
>
> +/**
>
> + This function is used to parse an ACPI table bitfield buffer.
>
> +
>
> + The ACPI table buffer is parsed using the ACPI table parser information
>
> + specified by a pointer to an array of ACPI_PARSER elements. This parser
>
> + function iterates through each item on the ACPI_PARSER array and logs the ACPI table bitfields.
>
> +
>
> + This function can optionally be used to parse ACPI tables and fetch specific
>
> + field values. The ItemPtr member of the ACPI_PARSER structure (where used)
>
> + is updated by this parser function to point to the selected field data
>
> + (e.g. useful for variable length nested fields).
>
> +
>
> + @param [in] Trace Trace the ACPI fields TRUE else only parse the
>
> + table.
>
> + @param [in] Indent Number of spaces to indent the output.
>
> + @param [in] AsciiName Optional pointer to an ASCII string that describes
>
> + the table being parsed.
>
> + @param [in] Ptr Pointer to the start of the buffer.
>
> + @param [in] Length Length of the buffer pointed by Ptr.
>
> + @param [in] Parser Pointer to an array of ACPI_PARSER structure that
>
> + describes the table being parsed.
>
> + @param [in] ParserItems Number of items in the ACPI_PARSER array.
>
> +
>
> + @retval Number of bits parsed.
>
> +**/
>
> +UINT32
>
> +EFIAPI
>
> +ParseAcpiBitFields (
>
> + IN BOOLEAN Trace,
>
> + IN UINT32 Indent,
>
> + IN CONST CHAR8 *AsciiName OPTIONAL,
>
> + IN UINT8 *Ptr,
>
> + IN UINT32 Length,
>
> + IN CONST ACPI_PARSER *Parser,
>
> + IN UINT32 ParserItems
>
> + );
>
> +
>
> /**
>
> This is a helper macro to pass parameters to the Parser functions.
>
>
>
> diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
> index cb193a5ea449..94ee26f42ab9 100644
> --- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
> @@ -2,12 +2,14 @@
> ACPI parser
>
>
>
> Copyright (c) 2016 - 2021, Arm Limited. All rights reserved.
>
> + Copyright (c) 2021, AMD Incorporated. All rights reserved.
>
> SPDX-License-Identifier: BSD-2-Clause-Patent
>
> **/
>
>
>
> #include <Uefi.h>
>
> #include <Library/UefiLib.h>
>
> #include <Library/UefiBootServicesTableLib.h>
>
> +#include <Library/BaseMemoryLib.h>
>
> #include "AcpiParser.h"
>
> #include "AcpiView.h"
>
> #include "AcpiViewConfig.h"
>
> @@ -752,3 +754,186 @@ ParseAcpiHeader (
>
>
> return BytesParsed;
>
> }
>
> +
>
> +/**
>
> + This function is used to parse an ACPI table bitfield buffer.
>
> +
>
> + The ACPI table buffer is parsed using the ACPI table parser information
>
> + specified by a pointer to an array of ACPI_PARSER elements. This parser
>
> + function iterates through each item on the ACPI_PARSER array and logs the ACPI table bitfields.
>
> +
>
> + This function can optionally be used to parse ACPI tables and fetch specific
>
> + field values. The ItemPtr member of the ACPI_PARSER structure (where used)
>
> + is updated by this parser function to point to the selected field data
>
> + (e.g. useful for variable length nested fields).
>
> +
>
> + @param [in] Trace Trace the ACPI fields TRUE else only parse the
>
> + table.
>
> + @param [in] Indent Number of spaces to indent the output.
>
> + @param [in] AsciiName Optional pointer to an ASCII string that describes
>
> + the table being parsed.
>
> + @param [in] Ptr Pointer to the start of the buffer.
>
> + @param [in] Length Length in bytes of the buffer pointed by Ptr.
>
> + @param [in] Parser Pointer to an array of ACPI_PARSER structure that
>
> + describes the table being parsed.
>
> + @param [in] ParserItems Number of items in the ACPI_PARSER array.
>
> +
>
> + @retval Number of bits parsed.
>
> +**/
>
> +UINT32
>
> +EFIAPI
>
> +ParseAcpiBitFields (
>
> + IN BOOLEAN Trace,
>
> + IN UINT32 Indent,
>
> + IN CONST CHAR8 *AsciiName OPTIONAL,
>
> + IN UINT8 *Ptr,
>
> + IN UINT32 Length,
>
> + IN CONST ACPI_PARSER *Parser,
>
> + IN UINT32 ParserItems
>
> + )
>
> +{
>
> + UINT32 Index;
>
> + UINT32 Offset;
>
> + BOOLEAN HighLight;
>
> + UINTN OriginalAttribute;
>
> +
>
> + UINT64 Data;
>
> + UINT64 BitsData;
>
> +
>
> + if ((Length == 0) || (Length > 8)) {
>
> + IncrementErrorCount ();
>
> + Print (
>
> + L"\nERROR: Bitfield Length(%d) is zero or exceeding the 64 bit limit.\n",
>
> + Length
>
> + );
>
> + return 0;
>
> + }
>
> +
>
> + //
>
> + // set local variables to suppress incorrect compiler/analyzer warnings
>
> + //
>
> + OriginalAttribute = 0;
>
> + Offset = 0;
>
> +
>
> + // Increment the Indent
>
> + gIndent += Indent;
>
> +
>
> + CopyMem ((VOID *)&BitsData, (VOID *)Ptr, Length);
>
> + if (Trace && (AsciiName != NULL)) {
>
> + HighLight = GetColourHighlighting ();
>
> +
>
> + if (HighLight) {
>
> + OriginalAttribute = gST->ConOut->Mode->Attribute;
>
> + gST->ConOut->SetAttribute (
>
> + gST->ConOut,
>
> + EFI_TEXT_ATTR (
>
> + EFI_YELLOW,
>
> + ((OriginalAttribute&(BIT4|BIT5|BIT6))>>4)
>
> + )
>
> + );
>
> + }
>
> +
>
> + Print (
>
> + L"%*a%-*a :\n",
>
> + gIndent,
>
> + "",
>
> + (OUTPUT_FIELD_COLUMN_WIDTH - gIndent),
>
> + AsciiName
>
> + );
>
> + if (HighLight) {
>
> + gST->ConOut->SetAttribute (gST->ConOut, OriginalAttribute);
>
> + }
>
> + }
>
> +
>
> + for (Index = 0; Index < ParserItems; Index++) {
>
> + if ((Offset + Parser[Index].Length) > (Length * 8)) {
>
> + // For fields outside the buffer length provided, reset any pointers
>
> + // which were supposed to be updated by this function call
>
> + if (Parser[Index].ItemPtr != NULL) {
>
> + *Parser[Index].ItemPtr = NULL;
>
> + }
>
> +
>
> + // We don't parse past the end of the max length specified
>
> + continue;
>
> + }
>
> +
>
> + if (Parser[Index].Length == 0) {
>
> + // don't parse the bitfield whose length is zero
>
> + continue;
[SAMI] Is there a use-case where the bitfield length will be zero? I
think any unused bits would be represented as Reserved. Considering
this, Parser[Index].Length == 0 would mean an incorrect an incorrect
description inACPI_PARSER, right?
If so, the default case for the switch statement below would print
"ERROR: %a: CANNOT PARSE THIS FIELD, Field Length". Can you check this,
please?
[/SAMI]
> + }
>
> +
>
> + if (GetConsistencyChecking () &&
>
> + (Offset != Parser[Index].Offset))
>
> + {
>
> + IncrementErrorCount ();
>
> + Print (
>
> + L"\nERROR: %a: Offset Mismatch for %s\n"
>
> + L"CurrentOffset = %d FieldOffset = %d\n",
>
> + AsciiName,
>
> + Parser[Index].NameStr,
>
> + Offset,
>
> + Parser[Index].Offset
>
> + );
>
> + }
>
> +
>
> + // extract Bitfield data for the current item
>
> + Data = (BitsData >> Parser[Index].Offset) & ~(~0ULL << Parser[Index].Length);
>
> +
>
> + if (Trace) {
>
> + // if there is a Formatter function let the function handle
>
> + // the printing else if a Format is specified in the table use
>
> + // the Format for printing
>
> + PrintFieldName (2, Parser[Index].NameStr);
>
> + if (Parser[Index].PrintFormatter != NULL) {
>
> + Parser[Index].PrintFormatter (Parser[Index].Format, (UINT8 *)&Data);
>
> + } else if (Parser[Index].Format != NULL) {
>
> + // convert bit length to byte length
>
> + switch ((Parser[Index].Length + 7) >> 3) {
>
> + // print the data depends on byte size
>
> + case 1:
>
> + DumpUint8 (Parser[Index].Format, (UINT8 *)&Data);
>
> + break;
>
> + case 2:
>
> + DumpUint16 (Parser[Index].Format, (UINT8 *)&Data);
>
> + break;
>
> + case 3:
>
> + case 4:
>
> + DumpUint32 (Parser[Index].Format, (UINT8 *)&Data);
>
> + break;
>
> + case 5:
>
> + case 6:
>
> + case 7:
>
> + case 8:
>
> + DumpUint64 (Parser[Index].Format, (UINT8 *)&Data);
>
> + break;
>
> + default:
>
> + Print (
>
> + L"\nERROR: %a: CANNOT PARSE THIS FIELD, Field Length = %d\n",
>
> + AsciiName,
>
> + Parser[Index].Length
>
> + );
>
> + } // switch
>
> + }
>
> +
>
> + // Validating only makes sense if we are tracing
>
> + // the parsed table entries, to report by table name.
>
> + if (GetConsistencyChecking () &&
>
> + (Parser[Index].FieldValidator != NULL))
>
> + {
>
> + Parser[Index].FieldValidator ((UINT8 *)&Data, Parser[Index].Context);
>
> + }
>
> +
>
> + Print (L"\n");
>
> + } // if (Trace)
>
> +
>
> + if (Parser[Index].ItemPtr != NULL) {
>
> + *Parser[Index].ItemPtr = (VOID *)(UINT8 *)&Data;
[SAMI] ACPI_PARSER.ItemPtr is used to get a reference to the field data
in the original ACPI table data.
In the current case, Parser[Index].ItemPtr is being set to a local
variable (i.e. Data). I don't think this is what we want. I think it
would be better to not supportACPI_PARSER.ItemPtr for BitFields.
I would recommend adding a comment to clarify that ItemPtr is not
supported for BitFields in this function, as well as the documentation
for ACPI_PARSER structure.
[/SAMI]
>
> + }
>
> +
>
> + Offset += Parser[Index].Length;
>
> + } // for
>
> +
>
> + // Decrement the Indent
>
> + gIndent -= Indent;
>
> + return Offset;
>
> +}
>
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