From fdc5584110562fecf14ca0648add1d0409ef1c87 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Wed, 9 Mar 2022 16:40:45 -0500
Subject: [PATCH] Print memory map

---
 main.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 53 insertions(+), 6 deletions(-)

diff --git a/main.c b/main.c
index 42b5b43..7ca7213 100644
--- a/main.c
+++ b/main.c
@@ -22,14 +22,14 @@ static void write_uint(uint32_t n)
     write_string(&s[11u - i]);
 }
 
-static void write_ptr(size_t n)
+static void write_hex64(size_t n)
 {
     CHAR16 hexchars[] = L"0123456789ABCDEF";
     CHAR16 s[20] = {0};
     size_t s_i = 0u;
     for (size_t i = 0u; i < 16u; i++)
     {
-        if ((i != 0u) && ((i % 4u) == 0u))
+        if (i == 8u)
         {
             s[s_i++] = L'_';
         }
@@ -38,7 +38,7 @@ static void write_ptr(size_t n)
     write_string(s);
 }
 
-static void check_handle(EFI_HANDLE handle)
+static void check_gop_handle(EFI_HANDLE handle)
 {
     EFI_HANDLE interface = NULL;
     EFI_STATUS status = g_system_table->BootServices->HandleProtocol(handle,
@@ -59,12 +59,57 @@ static void check_handle(EFI_HANDLE handle)
     }
 
     write_string(L"interface is at ");
-    write_ptr((size_t)interface);
+    write_hex64((size_t)interface);
     write_string(L"\r\n");
 
     EFI_GRAPHICS_OUTPUT_PROTOCOL * gop = (EFI_GRAPHICS_OUTPUT_PROTOCOL *)interface;
 }
 
+static void dump_memory_map(void)
+{
+    static uint8_t memory_map_buffer[16384];
+    UINTN memory_map_size = sizeof(memory_map_buffer);
+    UINTN map_key;
+    UINTN descriptor_size;
+    UINT32 descriptor_version;
+    EFI_STATUS status = g_system_table->BootServices->GetMemoryMap(&memory_map_size,
+            memory_map_buffer,
+            &map_key,
+            &descriptor_size,
+            &descriptor_version);
+    write_string(L"GetMemoryMap status = ");
+    write_uint(status);
+    write_string(L"\r\n");
+    write_string(L"  memory_map_size = ");
+    write_uint(memory_map_size);
+    write_string(L"\r\n");
+    if (!EFI_ERROR(status))
+    {
+        write_string(L"  descriptor_size = ");
+        write_uint(descriptor_size);
+        write_string(L"\r\n");
+        size_t n_descriptors = memory_map_size / descriptor_size;
+        for (size_t i = 0u; i < n_descriptors; i++)
+        {
+            EFI_MEMORY_DESCRIPTOR * descriptor = (EFI_MEMORY_DESCRIPTOR *)&memory_map_buffer[i * descriptor_size];
+            if (descriptor->Type == EfiConventionalMemory)
+            {
+                write_string(L"  ");
+                write_hex64(descriptor->PhysicalStart);
+                write_string(L" : ");
+                write_hex64(descriptor->VirtualStart);
+                write_string(L", n=");
+                write_uint(descriptor->NumberOfPages);
+                write_string(L", t=");
+                write_uint(descriptor->Type);
+                write_string(L", a=");
+                write_hex64(descriptor->Attribute);
+                write_string(L"\r\n");
+            }
+        }
+    }
+}
+
 EFI_STATUS
 efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * system_table)
 {
@@ -80,9 +125,11 @@ efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * system_table)
         return status;
 
     write_string(L"system_table is at ");
-    write_ptr((size_t)system_table);
+    write_hex64((size_t)system_table);
     write_string(L"\r\n");
 
+    dump_memory_map();
+
     EFI_HANDLE buffer[10];
     UINTN buffer_size = sizeof(buffer);
     status = system_table->BootServices->LocateHandle(ByProtocol,
@@ -99,7 +146,7 @@ efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * system_table)
 
     for (size_t i = 0u; i < buffer_size; i++)
     {
-        check_handle(buffer[i]);
+        check_gop_handle(buffer[i]);
     }
 
     write_string(L"Press any key...\r\n");