OcAcpiLib: Provide Base lookup for ACPI patches (#237)

.gitignore

@@ -8,6 +8,7 @@ xcuserdata
 project.xcworkspace
 *.dSYM
 Utilities/AppleEfiSignTool/AppleEfiSignTool
+Utilities/ACPIe/ACPIe
 Utilities/acdtinfo/acdtinfo
 Utilities/disklabel/disklabel
 Utilities/EfiResTool/EfiResTool

Docs/Configuration.tex

@@ -967,6 +967,27 @@ \subsection{Patch Properties}\label{acpipropspatch}
 
 \begin{enumerate}
 
+\item
+  \texttt{Base}\\
+  \textbf{Type}: \texttt{plist\ string}\\
+  \textbf{Failsafe}: Empty (Ignored)\\
+  \textbf{Description}: Selects ACPI path base for patch lookup (or immediate
+  replacement) by obtaining the offset to the provided path.
+
+  Only fully-qualified absolute paths are supported (e.g. \texttt{\textbackslash \_SB\_.PCI0.GFX0}).
+  Currently supported object types are: \texttt{Device}, \texttt{Field}, \texttt{Method}.
+
+  \emph{Note}: Use with care, not all OEM tables can be parsed. Use \texttt{ACPIe}
+  utility to debug. \texttt{ACPIe} compiled  with \texttt{DEBUG=1 make} command
+  produces helpful ACPI lookup tracing.
+
+\item
+  \texttt{BaseSkip}\\
+  \textbf{Type}: \texttt{plist\ integer}\\
+  \textbf{Failsafe}: \texttt{0} (Do not skip any occurrences)\\
+  \textbf{Description}: Number of found \texttt{Base} occurrences to skip before
+  finds and replacements are applied.
+
 \item
   \texttt{Comment}\\
   \textbf{Type}: \texttt{plist\ string}\\
@@ -992,6 +1013,9 @@ \subsection{Patch Properties}\label{acpipropspatch}
   \textbf{Failsafe}: Empty\\
   \textbf{Description}: Data to find. Must be equal to \texttt{Replace} in size if set.
 
+  \emph{Note}: Can be empty, when \texttt{Base} is specified, immediate replacement
+  after \texttt{Base} lookup happens in this case.
+
 \item
   \texttt{Limit}\\
   \textbf{Type}: \texttt{plist\ integer}\\

Docs/Sample.plist

@@ -185,6 +185,10 @@
 		<key>Patch</key>
 		<array>
 			<dict>
+				<key>Base</key>
+				<string>\_SB_.PCI0.GFX0</string>
+				<key>BaseSkip</key>
+				<integer>0</integer>
 				<key>Comment</key>
 				<string>Replace one byte sequence with another</string>
 				<key>Count</key>

Docs/SampleCustom.plist

@@ -185,6 +185,10 @@
 		<key>Patch</key>
 		<array>
 			<dict>
+				<key>Base</key>
+				<string>\_SB_.PCI0.GFX0</string>
+				<key>BaseSkip</key>
+				<integer>0</integer>
 				<key>Comment</key>
 				<string>Replace one byte sequence with another</string>
 				<key>Count</key>

Include/Acidanthera/Library/OcAcpiLib.h

@@ -124,6 +124,14 @@ typedef struct {
   //
   CONST UINT8  *ReplaceMask;
   //
+  // Fully qualified name with ACPI path (e.g. \_SB_.PCI0.GFX0).
+  //
+  CONST CHAR8  *Base;
+  //
+  // Number of Base entries to skip before using.
+  //
+  UINT32       BaseSkip;
+  //
   // Patch size.
   //
   UINT32       Size;
@@ -304,4 +312,28 @@ AcpiDumpTables (
   IN EFI_FILE_PROTOCOL  *Root
   );
 
+/**
+  Finds offset of required entry in ACPI table in case it exists.
+
+  @param[in]  Table       Pointer to start of ACPI table.
+  @param[in]  PathString  Path to entry which must be found.
+  @param[in]  Entry       Number of entry which must be found.
+  @param[out] Offset      Offset of the entry if it was found.
+  @param[out] TableLength Length of ACPI table.
+
+  @retval EFI_SUCCESS           Required entry was found.
+  @retval EFI_NOT_FOUND         Required entry was not found.
+  @retval EFI_DEVICE_ERROR      Error occured during parsing ACPI table.
+  @retval EFI_OUT_OF_RESOURCES  Nesting limit has been reached.
+  @retval EFI_INVALID_PARAMETER Got wrong path to the entry.
+**/
+EFI_STATUS
+AcpiFindEntryInMemory (
+  IN     UINT8       *Table,
+  IN     CONST CHAR8 *PathString,
+  IN     UINT8       Entry,
+     OUT UINT32      *Offset,
+  IN     UINT32      TableLength OPTIONAL
+  );
+
 #endif // OC_ACPI_LIB_H

Include/Acidanthera/Library/OcConfigurationLib.h

@@ -60,6 +60,8 @@
   _(BOOLEAN                     , Enabled          ,     , FALSE                       , ()                   ) \
   _(OC_STRING                   , Comment          ,     , OC_STRING_CONSTR ("", _, __), OC_DESTR (OC_STRING) ) \
   _(OC_DATA                     , Find             ,     , OC_EDATA_CONSTR (_, __)     , OC_DESTR (OC_DATA)   ) \
+  _(OC_STRING                   , Base             ,     , OC_STRING_CONSTR ("", _, __), OC_DESTR (OC_STRING) ) \
+  _(UINT32                      , BaseSkip         ,     , 0                           , ()                   ) \
   _(UINT32                      , Limit            ,     , 0                           , ()                   ) \
   _(OC_DATA                     , Mask             ,     , OC_EDATA_CONSTR (_, __)     , OC_DESTR (OC_DATA)   ) \
   _(OC_DATA                     , Replace          ,     , OC_EDATA_CONSTR (_, __)     , OC_DESTR (OC_DATA)   ) \