[Kernel] Only copy a pointer to the IDT table to avoid OOB write

Author: codyd51

docs/todo.md

@@ -312,3 +312,11 @@ Read a config/max_cpus.txt to decide when to stop booting APs
 Read a config/resolution.txt to decide the resolution selected by the bootloader
 
 Auto install LLD link? Or llvm with brew? Need lld-link for the UEFI build
+
+// TODO(PT): It'd be nice to have some kind of font API that allowed anyone to retrieve a reference to a 
+// font from any point, instead of needing to pass references all the way through the control flow. 
+// Maybe there's an in-process font store that caches scanlines, etc, and fetches fonts from the FS. 
+// The 'fetch from FS' has a platform-specific implementation. To facilitate this (as the paths will be 
+// different on each OS), we could have an enum to model the possible font options, with an escape hatch 
+// 'get from this path' variant, which could perhaps hold different values depending on the OS. 
+

kernel/kernel/smp.c

@@ -56,8 +56,11 @@ void smp_init(void) {
 
     // Copy the IDT pointer
     idt_pointer_t* current_idt = kernel_idt_pointer();
+    // Crash because current_idt->table_size == 0xfff, and copying to 0x9400 causes it to write outside the AP bootstrap data page
+    printf("Current IDT %p size %p dest %p\n", current_idt, current_idt->table_size, AP_BOOTSTRAP_PARAM_IDT);
     // It's fine to copy the high-memory IDT as the bootstrap will enable paging before loading it
-    memcpy((void*)PMA_TO_VMA(AP_BOOTSTRAP_PARAM_IDT), current_idt, sizeof(idt_pointer_t) + current_idt->table_size);
+    //memcpy((void*)PMA_TO_VMA(AP_BOOTSTRAP_PARAM_IDT), current_idt, sizeof(idt_pointer_t) + current_idt->table_size);
+    memcpy((void*)PMA_TO_VMA(AP_BOOTSTRAP_PARAM_IDT), current_idt, sizeof(idt_pointer_t*));
 
     // Copy the C entry point
     uintptr_t ap_c_entry_point_addr = (uintptr_t)&ap_c_entry;