ArmPkg/ArmV7Lib: add function to test for presence of MP extensions

Some MMU manipulation is dependent on the presence of the multiprocessing
extensions. So add a function that returns this information.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18895 6f19259b-4bc3-4df7-8a09-765794883524

ArmPkg/Library/ArmLib/ArmV7/ArmLibSupportV7.S

@@ -19,6 +19,7 @@
 .align 2
 
 GCC_ASM_EXPORT(ArmIsMpCore)
+GCC_ASM_EXPORT(ArmHasMpExtensions)
 GCC_ASM_EXPORT(ArmEnableAsynchronousAbort)
 GCC_ASM_EXPORT(ArmDisableAsynchronousAbort)
 GCC_ASM_EXPORT(ArmEnableIrq)
@@ -44,6 +45,12 @@ ASM_PFX(ArmIsMpCore):
   movne   R0, #0
   bx      LR
 
+ASM_PFX(ArmHasMpExtensions):
+  mrc     p15,0,R0,c0,c0,5
+  // Get Multiprocessing extension (bit31)
+  lsr     R0, R0, #31
+  bx      LR
+
 ASM_PFX(ArmEnableAsynchronousAbort):
   cpsie   a
   isb

ArmPkg/Library/ArmLib/ArmV7/ArmLibSupportV7.asm

@@ -15,6 +15,7 @@
 
 
     EXPORT  ArmIsMpCore
+    EXPORT  ArmHasMpExtensions
     EXPORT  ArmEnableAsynchronousAbort
     EXPORT  ArmDisableAsynchronousAbort
     EXPORT  ArmEnableIrq
@@ -43,6 +44,12 @@ ArmIsMpCore
   movne   R0, #0
   bx      LR
 
+ArmHasMpExtensions
+  mrc     p15,0,R0,c0,c0,5
+  // Get Multiprocessing extension (bit31)
+  lsr     R0, R0, #31
+  bx      LR
+
 ArmEnableAsynchronousAbort
   cpsie   a
   isb

ArmPkg/Library/ArmLib/ArmV7/ArmV7Lib.h

@@ -28,5 +28,11 @@ ArmReadIdMmfr0 (
   VOID
   );
 
+BOOLEAN
+EFIAPI
+ArmHasMpExtensions (
+  VOID
+  );
+
 #endif // __ARM_V7_LIB_H__