Splitting out UEFI bootloader code from kernel

Now the bootloader should be responsible for all initial setup, loading the kernel, and then handing off to the kernel with proper data in place.
2025-12-10 08:24:32 -08:00 · 2017-07-26 01:41:46 -07:00
parent 9ae583b1ec
commit d02e1d97d9
14 changed files with 242 additions and 53 deletions
--- a/src/boot/memory.c
+++ b/src/boot/memory.c
@@ -0,0 +1,100 @@
+#include <efi.h>
+#include <efilib.h>
+
+#include "memory.h"
+#include "utility.h"
+
+const UINTN PAGE_SIZE = 4096;
+
+const CHAR16 *memory_type_names[] = {
+    L"EfiReservedMemoryType",
+    L"EfiLoaderCode",
+    L"EfiLoaderData",
+    L"EfiBootServicesCode",
+    L"EfiBootServicesData",
+    L"EfiRuntimeServicesCode",
+    L"EfiRuntimeServicesData",
+    L"EfiConventionalMemory",
+    L"EfiUnusableMemory",
+    L"EfiACPIReclaimMemory",
+    L"EfiACPIMemoryNVS",
+    L"EfiMemoryMappedIO",
+    L"EfiMemoryMappedIOPortSpace",
+    L"EfiPalCode",
+    L"EfiPersistentMemory",
+};
+
+static const CHAR16 *memory_type_name(UINT32 value) {
+    if (value >= (sizeof(memory_type_names)/sizeof(CHAR16*)))
+        return L"Bad Type Value";
+    return memory_type_names[value];
+}
+
+void EFIAPI memory_update_addresses(EFI_EVENT UNUSED *event, void UNUSED *context) {
+    ST->RuntimeServices->ConvertPointer(0, (void **)&BS);
+    ST->RuntimeServices->ConvertPointer(0, (void **)&ST);
+}
+
+EFI_STATUS memory_virtualize() {
+    EFI_STATUS status;
+    EFI_EVENT event;
+
+    status = ST->BootServices->CreateEvent(EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE,
+            TPL_CALLBACK, (EFI_EVENT_NOTIFY)&memory_update_addresses, NULL, &event);
+    CHECK_EFI_STATUS_OR_RETURN(status, "Failed to create memory update event");
+
+    return status;
+}
+
+EFI_STATUS memory_get_map(EFI_MEMORY_DESCRIPTOR **buffer, UINTN *buffer_size,
+                          UINTN *key, UINTN *desc_size, UINT32 *desc_version) {
+    EFI_STATUS status;
+
+    UINTN needs_size = 0;
+    status = ST->BootServices->GetMemoryMap(&needs_size, 0, key, desc_size, desc_version);
+    if (status != EFI_BUFFER_TOO_SMALL) {
+        CHECK_EFI_STATUS_OR_RETURN(status, "Failed to load memory map");
+    }
+
+    // Give some extra buffer to account for changes.
+    *buffer_size = needs_size + 256;
+    Print(L"Trying to load memory map with size %d.\n", *buffer_size);
+    status = ST->BootServices->AllocatePool(EfiLoaderData, *buffer_size, (void**)buffer);
+    CHECK_EFI_STATUS_OR_RETURN(status, "Failed to allocate space for memory map");
+
+    status = ST->BootServices->GetMemoryMap(buffer_size, *buffer, key, desc_size, desc_version);
+    CHECK_EFI_STATUS_OR_RETURN(status, "Failed to load memory map");
+    return EFI_SUCCESS;
+}
+
+EFI_STATUS memory_dump_map() {
+    EFI_MEMORY_DESCRIPTOR *buffer;
+    UINTN buffer_size, desc_size, key;
+    UINT32 desc_version;
+
+    EFI_STATUS status = memory_get_map(&buffer, &buffer_size, &key,
+        &desc_size, &desc_version);
+    CHECK_EFI_STATUS_OR_RETURN(status, "Failed to get memory map");
+
+    const UINTN count = buffer_size / desc_size;
+
+    Print(L"Memory map:\n");
+    Print(L"\t  Descriptor Count: %d (%d bytes)\n", count, buffer_size);
+    Print(L"\t       Version Key: %d\n", key);
+    Print(L"\tDescriptor Version: %d (%d bytes)\n\n", desc_version, desc_size);
+
+    EFI_MEMORY_DESCRIPTOR *end = (EFI_MEMORY_DESCRIPTOR *)((uint8_t *)buffer + buffer_size);
+    EFI_MEMORY_DESCRIPTOR *d = buffer;
+    while (d < end) {
+        UINTN size_bytes = d->NumberOfPages * PAGE_SIZE;
+
+        Print(L"Type: %s  Attr: 0x%x\n", memory_type_name(d->Type), d->Attribute);
+        Print(L"\t Physical  %016llx - %016llx\n", d->PhysicalStart, d->PhysicalStart + size_bytes);
+        Print(L"\t  Virtual  %016llx - %016llx\n\n", d->VirtualStart, d->VirtualStart + size_bytes);
+
+        d = (EFI_MEMORY_DESCRIPTOR *)((uint8_t *)d + desc_size);
+    }
+
+    ST->BootServices->FreePool(buffer);
+    return EFI_SUCCESS;
+}