ArmPkg/ArmLib: Add ArmHasTrbe () helper function

Create a helper function to query whether ID_AA64MFR1_EL1 indicates
presence of the Trace Buffer Extension (TRBE). This feature is only
visible in AARCH64 state.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>

ArmPkg/Include/Chipset/AArch64.h

@@ -31,6 +31,9 @@
 #define AARCH64_PFR0_FP   (0xF << 16)
 #define AARCH64_PFR0_GIC  (0xF << 24)
 
+// ID_AA64DFR0 - AArch64 Debug Feature Register 0 definitions
+#define AARCH64_DFR0_TRBE  (0xFULL << 44)
+
 // SCR - Secure Configuration Register definitions
 #define SCR_NS   (1 << 0)
 #define SCR_IRQ  (1 << 1)

ArmPkg/Include/Library/ArmLib.h

@@ -780,6 +780,19 @@ EFIAPI
 ArmHasVhe (
   VOID
   );
+
+/**
+  Checks whether the CPU implements the Trace Buffer Extension.
+
+  @retval TRUE  FEAT_TRBE is implemented.
+  @retval FALSE FEAT_TRBE is not mplemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasTrbe (
+  VOID
+  );
+
 #endif // MDE_CPU_AARCH64
 
 #ifdef MDE_CPU_ARM

ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c

@@ -119,3 +119,18 @@ ArmHasVhe (
 {
   return ((ArmReadIdAA64Mmfr1 () & AARCH64_MMFR1_VH) != 0);
 }
+
+/**
+  Checks whether the CPU implements the Trace Buffer Extension.
+
+  @retval TRUE  FEAT_TRBE is implemented.
+  @retval FALSE FEAT_TRBE is not mplemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasTrbe (
+  VOID
+  )
+{
+  return ((ArmReadIdAA64Dfr0 () & AARCH64_DFR0_TRBE) != 0);
+}