From f761d0a4453186c4e3bce719b68280673190c8b6 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sat, 26 Mar 2022 00:36:23 -0400
Subject: [PATCH] Jump to HULK from assembly

---
 src/hello/hello.d | 11 +++++++----
 src/hulk/hulk.d   |  2 +-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/hello/hello.d b/src/hello/hello.d
index d452125..7dd2f5c 100644
--- a/src/hello/hello.d
+++ b/src/hello/hello.d
@@ -11,6 +11,7 @@ import hulk.header : HulkHeader = Header;
 import hos.page_table;
 import hos.cpu;
 import hos.memory;
+import ldc.llvmasm;
 
 __gshared EFI_SYSTEM_TABLE * st;
 private __gshared BootInfo bootinfo;
@@ -376,10 +377,12 @@ private void build_page_tables(ulong max_physical_address, ulong bss_phys, ulong
 /**
  * Jump to HULK entry point.
  */
-private void jump_to_hulk()
+private void jump_to_hulk(ulong stack_end)
 {
-    void function(BootInfo *) hulk_entry_fn = cast(void function(BootInfo *))hulk_header().entry;
-    hulk_entry_fn(&bootinfo);
+    __asm(
+            "jmpq *$0",
+            "r,{rdi},{rsp}",
+            hulk_header().entry, &bootinfo, stack_end);
 }
 
 /**
@@ -431,7 +434,7 @@ extern (C) EFI_STATUS efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * st)
     bootinfo.bss_phys = bss_phys;
     bootinfo.stack_phys = stack_phys;
 
-    jump_to_hulk();
+    jump_to_hulk(stack_phys + hulk_stack_size());
 
     return EFI_SUCCESS;
 }
diff --git a/src/hulk/hulk.d b/src/hulk/hulk.d
index 13058bd..a63178f 100644
--- a/src/hulk/hulk.d
+++ b/src/hulk/hulk.d
@@ -26,7 +26,7 @@ private __gshared Header hulk_header = {
  *
  * @param bootinfo Pointer to HULK boot information structure.
  */
-extern(C) void hulk_start(ulong rdi, ulong rsi, ulong rdx, BootInfo * bootinfo)
+void hulk_start(BootInfo * bootinfo)
 {
     fb.initialize(bootinfo.fb.buffer, bootinfo.fb.width, bootinfo.fb.height, bootinfo.fb.stride);
     console.initialize();