ArmPlatformPkg/Sec: clean up FP enabling code

UEFI defines that FP support is required on AArch64, whereas many
platforms enable it anyway on Arm. But when it's enabled, C code can
generate instructions targeting FP registers, so:

- move ArmEnableVFP call to asm
- make it unconditional on AArch64

Signed-off-by: Leif Lindholm <leif.lindholm@oss.qualcomm.com>

ArmPlatformPkg/PeilessSec/AArch64/ArchPeilessSec.c

@@ -18,11 +18,6 @@ ArchInitialize (
   VOID
   )
 {
-  // Enable Floating Point
-  if (FixedPcdGet32 (PcdVFPEnabled)) {
-    ArmEnableVFP ();
-  }
-
   if (ArmReadCurrentEL () == AARCH64_EL2) {
     // Trap General Exceptions. All exceptions that would be routed to EL1 are routed to EL2
     ArmWriteHcr (ARM_HCR_TGE);

ArmPlatformPkg/PeilessSec/AArch64/ModuleEntryPoint.S

@@ -11,6 +11,10 @@ ASM_FUNC(_ModuleEntryPoint)
   // Do early platform specific actions
   bl    ASM_PFX(ArmPlatformPeiBootAction)
 
+  // Enable Floating Point. This needs to be done before entering C code, which
+  // may use FP/SIMD registers.
+  bl    ArmEnableVFP
+
 // Check if we can install the stack at the top of the System Memory or if we need
 // to install the stacks at the bottom of the Firmware Device (case the FD is located
 // at the top of the DRAM)

ArmPlatformPkg/PeilessSec/Arm/ArchPeilessSec.c

@@ -18,8 +18,4 @@ ArchInitialize (
 {
   // Enable program flow prediction, if supported.
   ArmEnableBranchPrediction ();
-
-  if (FixedPcdGet32 (PcdVFPEnabled)) {
-    ArmEnableVFP ();
-  }
 }

ArmPlatformPkg/PeilessSec/Arm/ModuleEntryPoint.S

@@ -13,6 +13,12 @@ ASM_FUNC(_ModuleEntryPoint)
   // Do early platform specific actions
   bl    ASM_PFX(ArmPlatformPeiBootAction)
 
+#if (FixedPcdGet32 (PcdVFPEnabled))
+  // Enable Floating Point. This needs to be done before entering C code, which
+  // may use FP/SIMD registers.
+  bl    ArmEnableVFP
+#endif
+
 // Check if we can install the stack at the top of the System Memory or if we need
 // to install the stacks at the bottom of the Firmware Device (case the FD is located
 // at the top of the DRAM)

ArmPlatformPkg/PeilessSec/PeilessSec.inf

@@ -70,9 +70,11 @@
   gArmTokenSpaceGuid.PcdFdSize
   gArmTokenSpaceGuid.PcdFvBaseAddress
   gArmTokenSpaceGuid.PcdFvSize
-  gArmTokenSpaceGuid.PcdVFPEnabled
   gEmbeddedTokenSpaceGuid.PcdPrePiCpuIoSize
 
+[FixedPcd.ARM]
+  gArmTokenSpaceGuid.PcdVFPEnabled
+
 [Pcd]
   gArmTokenSpaceGuid.PcdSystemMemoryBase
   gArmTokenSpaceGuid.PcdSystemMemorySize

ArmPlatformPkg/Sec/Arm/ModuleEntryPoint.S

@@ -11,6 +11,12 @@ ASM_FUNC(_ModuleEntryPoint)
   // Do early platform specific actions
   bl    ASM_PFX(ArmPlatformPeiBootAction)
 
+#if (FixedPcdGet32 (PcdVFPEnabled))
+  // Enable Floating Point. This needs to be done before entering C code, which
+  // may use FP/SIMD registers.
+  bl    ArmEnableVFP
+#endif
+
   // Get the top of the primary stacks (and the base of the secondary stacks)
   MOV32 (r1, FixedPcdGet64(PcdCPUCoresStackBase) + FixedPcdGet32(PcdCPUCorePrimaryStackSize))
 

ArmPlatformPkg/Sec/Sec.c

@@ -223,11 +223,6 @@ CEntryPoint (
   ASSERT (((UINTN)PeiVectorTable & ARM_VECTOR_TABLE_ALIGNMENT) == 0);
   ArmWriteVBar ((UINTN)PeiVectorTable);
 
-  // Enable Floating Point
-  if (FixedPcdGet32 (PcdVFPEnabled)) {
-    ArmEnableVFP ();
-  }
-
   // Invoke "ProcessLibraryConstructorList" to have all library constructors
   // called.
   ProcessLibraryConstructorList ();

ArmPlatformPkg/Sec/Sec.inf

@@ -58,9 +58,11 @@
 [FixedPcd]
   gArmTokenSpaceGuid.PcdFvBaseAddress
   gArmTokenSpaceGuid.PcdFvSize
-  gArmTokenSpaceGuid.PcdVFPEnabled
 
   gArmPlatformTokenSpaceGuid.PcdCPUCoresStackBase
   gArmPlatformTokenSpaceGuid.PcdCPUCorePrimaryStackSize
 
   gEfiMdeModulePkgTokenSpaceGuid.PcdInitValueInTempStack
+
+[FixedPcd.ARM]
+  gArmTokenSpaceGuid.PcdVFPEnabled