use linker script

CosmosOS · Dec 3, 2023 · c2c1395 · c2c1395
1 parent 8ffeaf7
commit c2c1395
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Showing 3 changed files with 111 additions and 21 deletions.
diff --git a/source/Cosmos.Build.Tasks/Ld.cs b/source/Cosmos.Build.Tasks/Ld.cs
@@ -25,7 +25,10 @@ public class Ld : ToolTask
 
         public string DataAddress { get; set; }
 
-        public string BssAddress { get; set; }
+        public string BssAddress { get; set; }
+
+        [Required]
+        public string TargetArchitecture { get; set; }
 
         #endregion
 
@@ -131,17 +134,95 @@ protected override string GenerateCommandLineCommands()
         {
             CommandLineBuilder xBuilder = new();
 
-            xBuilder.AppendSwitchIfNotNull("-Ttext ", TextAddress);
-            xBuilder.AppendSwitchIfNotNull("-Tdata ", DataAddress);
-            xBuilder.AppendSwitchIfNotNull("-Tbss ", BssAddress);
-            xBuilder.AppendSwitchIfNotNull("-e ", Entry);
             xBuilder.AppendSwitchIfNotNull("-o ", OutputFile);
 
-            xBuilder.AppendFileNamesIfNotNull(InputFiles, " ");
-            xBuilder.AppendSwitch("-m elf_x86_64");
-
-            Log.LogMessage(MessageImportance.High, xBuilder.ToString());
-
+            xBuilder.AppendFileNamesIfNotNull(InputFiles, " ");
+
+            if (TargetArchitecture == "amd64")
+            {
+                var dir = Path.GetDirectoryName(OutputFile);
+                var path = dir + "/linker.ld";
+                xBuilder.AppendSwitch("-m elf_x86_64");
+                xBuilder.AppendSwitchIfNotNull("-T ", path);
+
+
+
+                File.WriteAllText(path, @"/* Tell the linker that we want an x86_64 ELF64 output file */
+OUTPUT_FORMAT(elf64-x86-64)
+OUTPUT_ARCH(i386:x86-64)
+ 
+/* We want the symbol _start to be our entry point */
+ENTRY(" + Entry + @")
+ 
+/* Define the program headers we want so the bootloader gives us the right */
+/* MMU permissions */
+PHDRS
+{
+    text    PT_LOAD    FLAGS((1 << 0) | (1 << 2)) ; /* Execute + Read */
+    rodata  PT_LOAD    FLAGS((1 << 2)) ;            /* Read only */
+    data    PT_LOAD    FLAGS((1 << 1) | (1 << 2)) ; /* Write + Read */
+    dynamic PT_DYNAMIC FLAGS((1 << 1) | (1 << 2)) ; /* Dynamic PHDR for relocations */
+}
+ 
+SECTIONS
+{
+    /* We wanna be placed in the topmost 2GiB of the address space, for optimisations */
+    /* and because that is what the Limine spec mandates. */
+    /* Any address in this region will do, but often 0xffffffff80000000 is chosen as */
+    /* that is the beginning of the region. */
+    . = 0xffffffff80000000;
+ 
+    .text : {
+        *(.text .text.*)
+    } :text
+ 
+    /* Move to the next memory page for .rodata */
+    . += CONSTANT(MAXPAGESIZE);
+ 
+    .rodata : {
+        *(.rodata .rodata.*)
+    } :rodata
+ 
+    /* Move to the next memory page for .data */
+    . += CONSTANT(MAXPAGESIZE);
+ 
+    .data : {
+        *(.data .data.*)
+    } :data
+ 
+    /* Dynamic section for relocations, both in its own PHDR and inside data PHDR */
+    .dynamic : {
+        *(.dynamic)
+    } :data :dynamic
+ 
+    /* NOTE: .bss needs to be the last thing mapped to :data, otherwise lots of */
+    /* unnecessary zeros will be written to the binary. */
+    /* If you need, for example, .init_array and .fini_array, those should be placed */
+    /* above this. */
+    .bss : {
+        *(.bss .bss.*)
+        *(COMMON)
+    } :data
+ 
+    /* Discard .note.* and .eh_frame since they may cause issues on some hosts. */
+    /DISCARD/ : {
+        *(.eh_frame)
+        *(.note .note.*)
+    }
+}");
+            }
+            else
+            {
+                xBuilder.AppendSwitch("-m elf_i386");
+
+                xBuilder.AppendSwitchIfNotNull("-Ttext ", TextAddress);
+                xBuilder.AppendSwitchIfNotNull("-Tdata ", DataAddress);
+                xBuilder.AppendSwitchIfNotNull("-Tbss ", BssAddress);
+                xBuilder.AppendSwitchIfNotNull("-e ", Entry);
+            }
+
+            Log.LogMessage(MessageImportance.High, xBuilder.ToString());
+
             return xBuilder.ToString();
         }
 

diff --git a/source/Cosmos.Build.Tasks/Nasm.cs b/source/Cosmos.Build.Tasks/Nasm.cs
@@ -13,10 +13,10 @@ enum OutputFormatEnum
         {
             Bin,
             ELF
-        }
-
+        }
+
         #region Task Parameters
-        
+
         [Required]
         public string InputFile { get; set; }
 
@@ -30,7 +30,10 @@ public string OutputFormat
             set => mOutputFormat = (OutputFormatEnum)Enum.Parse(typeof(OutputFormatEnum), value, true);
         }
 
-        public string OptimizationLevel { get; set; }
+        public string OptimizationLevel { get; set; }
+
+        [Required]
+        public string TargetArchitecture { get; set; }
 
         #endregion
 
@@ -99,11 +102,15 @@ protected override string GenerateCommandLineCommands()
             {
                 xBuilder.AppendSwitch("-dBIN_COMPILATION");
             }
-            xBuilder.AppendSwitch("-m amd64");
-
-            /* Apply the optimization level that the user chose */
-	    if(!String.IsNullOrWhiteSpace(OptimizationLevel) && !String.IsNullOrWhiteSpace(OptimizationLevel))
-            	xBuilder.AppendSwitch($"-O{OptimizationLevel}");
+
+            if (TargetArchitecture == "amd64")
+            {
+                xBuilder.AppendSwitch("-m amd64");
+            }
+
+            /* Apply the optimization level that the user chose */
+            if (!String.IsNullOrWhiteSpace(OptimizationLevel) && !String.IsNullOrWhiteSpace(OptimizationLevel))
+                xBuilder.AppendSwitch($"-O{OptimizationLevel}");
 
             xBuilder.AppendFileNameIfNotNull(InputFile);
 

diff --git a/source/Cosmos.Build.Tasks/build/Cosmos.Build.targets b/source/Cosmos.Build.Tasks/build/Cosmos.Build.targets
@@ -228,7 +228,8 @@
               OutputFormat="$(BinFormat)"
               ToolPath="$(NasmToolPath)"
               ToolExe="$(NasmToolExe)"
-	      OptimizationLevel="$(OptimizationLevel)"/>
+              OptimizationLevel="$(OptimizationLevel)"
+              TargetArchitecture="$(TargetArchitecture)"/>
 
     </Target>
 
@@ -255,7 +256,8 @@
             DataAddress="0x1000000"
             Entry="Kernel_Start"
             ToolPath="$(LdToolPath)"
-            ToolExe="$(LdToolExe)" />
+            ToolExe="$(LdToolExe)"
+            TargetArchitecture="$(TargetArchitecture)"/>
 
     </Target>