X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=ArmVirtPkg%2FPrePi%2FAArch64%2FModuleEntryPoint.S;h=3296aedfe9aac671cc304e94a3f0aa087c111f5c;hp=7a9c0c3787cc2b4512e48df31c3cbd2a9fff7df2;hb=832709565e76a3f068848964a9c1dac4fa5d21f2;hpb=888559acf98ae954af0418c1f72bc603aa9b9e88

diff --git a/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S b/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
index 7a9c0c3787..3296aedfe9 100644
--- a/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
+++ b/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
@@ -49,8 +49,7 @@ ASM_FUNC(_ModuleEntryPoint)
   b     .Lreloc_loop
 .Lreloc_done:
 
-  // Do early platform specific actions
-  bl    ASM_PFX(ArmPlatformPeiBootAction)
+  bl    ASM_PFX(DiscoverDramFromDt)
 
   // Get ID of this CPU in Multicore system
   bl    ASM_PFX(ArmReadMpidr)
@@ -140,3 +139,77 @@ _GetStackBase:
 
 _NeverReturn:
   b _NeverReturn
+
+// VOID
+// DiscoverDramFromDt (
+//   VOID   *DeviceTreeBaseAddress,   // passed by loader in x0
+//   VOID   *ImageBase                // passed by FDF trampoline in x1
+//   );
+ASM_PFX(DiscoverDramFromDt):
+  //
+  // If we are booting from RAM using the Linux kernel boot protocol, x0 will
+  // point to the DTB image in memory. Otherwise, use the default value defined
+  // by the platform.
+  //
+  cbnz  x0, 0f
+  ldr   x0, PcdGet64 (PcdDeviceTreeInitialBaseAddress)
+
+0:mov   x29, x30            // preserve LR
+  mov   x28, x0             // preserve DTB pointer
+  mov   x27, x1             // preserve base of image pointer
+
+  //
+  // The base of the runtime image has been preserved in x1. Check whether
+  // the expected magic number can be found in the header.
+  //
+  ldr   w8, .LArm64LinuxMagic
+  ldr   w9, [x1, #0x38]
+  cmp   w8, w9
+  bne   .Lout
+
+  //
+  //
+  // OK, so far so good. We have confirmed that we likely have a DTB and are
+  // booting via the arm64 Linux boot protocol. Update the base-of-image PCD
+  // to the actual relocated value, and add the shift of PcdFdBaseAddress to
+  // PcdFvBaseAddress as well
+  //
+  adr   x8, PcdGet64 (PcdFdBaseAddress)
+  adr   x9, PcdGet64 (PcdFvBaseAddress)
+  ldr   x6, [x8]
+  ldr   x7, [x9]
+  sub   x7, x7, x6
+  add   x7, x7, x1
+  str   x1, [x8]
+  str   x7, [x9]
+
+  //
+  // Discover the memory size and offset from the DTB, and record in the
+  // respective PCDs. This will also return false if a corrupt DTB is
+  // encountered. Since we are calling a C function, use the window at the
+  // beginning of the FD image as a temp stack.
+  //
+  adr   x1, PcdGet64 (PcdSystemMemoryBase)
+  adr   x2, PcdGet64 (PcdSystemMemorySize)
+  mov   sp, x7
+  bl    FindMemnode
+  cbz   x0, .Lout
+
+  //
+  // Copy the DTB to the slack space right after the 64 byte arm64/Linux style
+  // image header at the base of this image (defined in the FDF), and record the
+  // pointer in PcdDeviceTreeInitialBaseAddress.
+  //
+  adr   x8, PcdGet64 (PcdDeviceTreeInitialBaseAddress)
+  add   x27, x27, #0x40
+  str   x27, [x8]
+
+  mov   x0, x27
+  mov   x1, x28
+  bl    CopyFdt
+
+.Lout:
+  ret    x29
+
+.LArm64LinuxMagic:
+  .byte   0x41, 0x52, 0x4d, 0x64