x86_64: implement robust C++ global initialization

Implement a comprehensive mechanism to ensure correct C++ runtime
initialization before the kernel main function is called. This replaces
the previous, incomplete reliance on an `_init` function.

The new design robustly handles both legacy `.ctors` and modern
`.init_array` initialization schemes used by the GNU toolchain. A single
C++ function, `invoke_global_constructors`, now iterates through both
arrays of function pointers to ensure all types of global initializers
are executed.

1 files changed, 9 insertions, 31 deletions

diff --git a/arch/x86_64/scripts/kernel.ld b/arch/x86_64/scripts/kernel.ld
index 6ba8b80..064b8d7 100644
--- a/arch/x86_64/scripts/kernel.ld
+++ b/arch/x86_64/scripts/kernel.ld
@@ -68,33 +68,11 @@ SECTIONS
   . = ALIGN(4K);
   . += TEACHOS_VMA;
 
-  .init ALIGN(4K) : AT(ADDR(.init) - TEACHOS_VMA)
-  {
-    /* 
-     * Make sure that the crt code is wrapped around the compiler generated
-     * initialization code.
-     */
-    KEEP(*crti.s.o*(.init))
-    KEEP(*(EXCLUDE_FILE (*crti.s.o* *crtn.s.o*) .init))
-    KEEP(*crtn.s.o*(.init))
-  } :text
-
-  .fini ALIGN(4K) : AT(ADDR (.fini) - TEACHOS_VMA)
-  {
-    /* 
-     * Make sure that the crt code is wrapped around the compiler generated
-     * finalizer code.
-     */
-    KEEP(*crti.s.o*(.fini))
-    KEEP(*(EXCLUDE_FILE (*crti.s.o* *crtn.s.o*) .fini))
-    KEEP(*crtn.s.o*(.fini))
-  }
-
   .stl_text ALIGN(4K) : AT(ADDR (.stl_text) - TEACHOS_VMA)
   {
     *(.stl_text .stl_text*)
     KEEP(*libstdc++.a:*(.text .text.*))
-  }
+  } :text
 
   .text ALIGN(4K) : AT(ADDR (.text) - TEACHOS_VMA)
   {
@@ -114,18 +92,18 @@ SECTIONS
 
   .ctors ALIGN(4K) : AT (ADDR (.ctors) - TEACHOS_VMA)
   {
-    KEEP(*crtbegin.o(.ctors))
-    KEEP(*(EXCLUDE_FILE (*crtend.o) .ctors))
+    __ctors_start = .;
     KEEP(*(SORT(.ctors.*)))
-    KEEP(*crtend.o(.ctors))
+    KEEP(*(.ctors))
+    __ctors_end = .;
   } :data
 
-  .dtors ALIGN(4K) : AT (ADDR (.dtors) - TEACHOS_VMA)
+  .init_array ALIGN(4K) : AT (ADDR (.init_array) - TEACHOS_VMA)
   {
-    KEEP(*crtbegin.o(.dtors))
-    KEEP(*(EXCLUDE_FILE (*crtend.o) .dtors))
-    KEEP(*(SORT(.dtors.*)))
-    KEEP(*crtend.o(.dtors))
+    __init_array_start = .;
+    KEEP(*(SORT_BY_INIT_PRIORITY(.init_array.*)))
+    KEEP(*(.init_array))
+    __init_array_end = .;
   }
 
   .bss ALIGN(4K) : AT (ADDR (.bss) - TEACHOS_VMA)