Relocate edk2 to high memory before boot

This may allow Linux to boot more easily?

Pixel3XL/Library/Pixel3XLLib/Pixel3XLHelper.S

@@ -18,7 +18,30 @@
 .align 3
 
 ASM_FUNC(ArmPlatformPeiBootAction)
+startlabel:
+  // check if we're located at expected location
+  adr	x4, .
+  ldr	x5, =ArmPlatformPeiBootAction
+  cmp	x4, x5
+  bne	docopy
   ret
+docopy:
+  // find our start address by getting our expected offset, then subtracting it from our actual address
+  ldr	x6, =FixedPcdGet64 (PcdFdBaseAddress)
+  sub	x5, x5, x6 // x5 now holds offset of ArmPlatformPeiBootAction from start of FD base
+  sub	x4, x4, x5 // x4 now holds address of actual FD base
+  // tweak the return address
+  sub	lr, lr, x4
+  add	lr, lr, x6
+  ldr	x5, =FixedPcdGet64 (PcdFdSize)
+  // crap memcpy
+loop:
+  ldp	x2, x3, [x4], #16
+  stp	x2, x3, [x6], #16
+  subs	x5, x5, #16
+  b.ne	loop
+  ret
+.ltorg
 
 //UINTN
 //ArmPlatformIsPrimaryCore (

Pixel3XL/Library/Pixel3XLLib/Pixel3XLLib.inf

@@ -42,3 +42,5 @@
   gArmTokenSpaceGuid.PcdArmPrimaryCoreMask
   gArmTokenSpaceGuid.PcdSystemMemoryBase
   gArmTokenSpaceGuid.PcdSystemMemorySize
+  gArmTokenSpaceGuid.PcdFdBaseAddress
+  gArmTokenSpaceGuid.PcdFdSize

Pixel3XL/Pixel3XL.fdf

@@ -25,7 +25,7 @@
 ################################################################################
 
 [FD.PIXEL3XL_UEFI]
-BaseAddress   = 0x80080000|gArmTokenSpaceGuid.PcdFdBaseAddress  # The base address of the Firmware in NOR Flash.
+BaseAddress   = 0xd0000000|gArmTokenSpaceGuid.PcdFdBaseAddress  # The base address of the Firmware in NOR Flash.
 Size          = 0x00200000|gArmTokenSpaceGuid.PcdFdSize         # The size in bytes of the FLASH Device
 ErasePolarity = 1