Add a kernel ELF module and load it in a new process.

Don't yet jump to userspace.

zion/loader/elf_loader.cpp

@@ -0,0 +1,74 @@
+#include "loader/elf_loader.h"
+
+#include "debug/debug.h"
+#include "memory/paging_util.h"
+
+namespace {
+
+typedef struct {
+  char ident[16];
+  uint16_t type;
+  uint16_t machine;
+  uint32_t version;
+  uint64_t entry;
+  uint64_t phoff;
+  uint64_t shoff;
+  uint32_t flags;
+  uint16_t ehsize;
+  uint16_t phentsize;
+  uint16_t phnum;
+  uint16_t shentsize;
+  uint16_t shnum;
+  uint16_t shstrndx;
+} Elf64Header;
+
+typedef struct {
+  uint32_t name;
+  uint32_t type;
+  uint64_t flags;
+  uint64_t addr;
+  uint64_t offset;
+  uint64_t size;
+  uint32_t link;
+  uint32_t info;
+  uint64_t addralign;
+  uint64_t entsize;
+} Elf64SectionHeader;
+
+typedef struct {
+  uint32_t type;
+  uint32_t flags;
+  uint64_t offset;
+  uint64_t vaddr;
+  uint64_t paddr;
+  uint64_t filesz;
+  uint64_t memsz;
+  uint64_t align;
+} Elf64ProgramHeader;
+
+void badmemcpy(uint64_t base, uint64_t offset, uint64_t dest) {
+  uint8_t* ptr = reinterpret_cast<uint8_t*>(base);
+  uint8_t* dest_ptr = reinterpret_cast<uint8_t*>(dest);
+  for (uint64_t i = 0; i < offset; i++) {
+    dest_ptr[i] = ptr[i];
+  }
+}
+
+}  // namespace
+
+void LoadElfProgram(uint64_t base, uint64_t offset) {
+  Elf64Header* header = reinterpret_cast<Elf64Header*>(base);
+  dbgln("phoff: %u phnum: %u", header->phoff, header->phnum);
+  Elf64ProgramHeader* programs =
+      reinterpret_cast<Elf64ProgramHeader*>(base + header->phoff);
+  for (uint64_t i = 0; i < header->phnum; i++) {
+    Elf64ProgramHeader& program = programs[i];
+    dbgln(
+        "prog: type: %u, flags: %u, offset: %u\n  vaddr: %m, paddr: %m\n  "
+        "filesz: %u, memsz: %u, align: %u",
+        program.type, program.flags, program.offset, program.vaddr,
+        program.paddr, program.filesz, program.memsz, program.align);
+    EnsureResident(program.vaddr, program.memsz);
+    badmemcpy(base + program.offset, program.filesz, program.vaddr);
+  }
+}

zion/loader/elf_loader.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <stdint.h>
+
+void LoadElfProgram(uint64_t base, uint64_t length);

zion/loader/init_loader.cpp

@@ -0,0 +1,30 @@
+#include "loader/init_loader.h"
+
+#include "boot/boot_info.h"
+#include "debug/debug.h"
+#include "loader/elf_loader.h"
+#include "scheduler/process.h"
+#include "scheduler/scheduler.h"
+
+namespace {
+
+const limine_file& GetInitProgram() {
+  const limine_module_response& resp = boot::GetModules();
+  dbgln("Dumping modules");
+  for (uint64_t i = 0; i < resp.module_count; i++) {
+    const limine_file& file = *resp.modules[i];
+    dbgln("%s,%m,%x", file.path, file.address, file.size);
+    // TODO eventually compare this file path.
+    return file;
+  }
+  panic("No init program found");
+}
+
+}  // namespace
+
+void LoadInitProgram() {
+  const limine_file& init_prog = GetInitProgram();
+
+  sched::InsertProcess(
+      new Process(reinterpret_cast<uint64_t>(init_prog.address)));
+}

zion/loader/init_loader.h

@@ -0,0 +1,3 @@
+#pragma once
+
+void LoadInitProgram();