Kernel: Add linker script for riscv64

Kernel/Arch/riscv64/linker.ld

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2023, Sönke Holz <sholz830@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+ENTRY(start)
+
+KERNEL_MAPPING_BASE = 0x2000000000;
+
+/* TODO: Add FLAGS to the program headers */
+PHDRS
+{
+    text PT_LOAD ;
+    data PT_LOAD ;
+    ksyms PT_LOAD ;
+    bss PT_LOAD ;
+}
+
+SECTIONS
+{
+    . = KERNEL_MAPPING_BASE;
+
+    start_of_kernel_image = .;
+
+    .text ALIGN(4K) :
+    {
+        start_of_kernel_text = .;
+        *(.text.first)
+
+        start_of_safemem_text = .;
+        KEEP(*(.text.safemem))
+        end_of_safemem_text = .;
+        start_of_safemem_atomic_text = .;
+        KEEP(*(.text.safemem.atomic))
+        end_of_safemem_atomic_text = .;
+
+        *(.text*)
+        end_of_kernel_text = .;
+    } :text
+
+    .rodata ALIGN(4K) :
+    {
+        start_heap_ctors = .;
+        *libkernel_heap.a:*(.init_array)
+        end_heap_ctors = .;
+
+        start_ctors = .;
+        *(.init_array)
+        end_ctors = .;
+
+        *(.rodata*)
+    } :data
+
+    .data ALIGN(4K) :
+    {
+        start_of_kernel_data = .;
+        *(.data*)
+        end_of_kernel_data = .;
+    } :data
+
+    .ksyms ALIGN(4K) :
+    {
+        start_of_kernel_ksyms = .;
+        *(.kernel_symbols)
+        end_of_kernel_ksyms = .;
+    } :ksyms
+
+    .bss ALIGN(4K) (NOLOAD) :
+    {
+        start_of_bss = .;
+        *(.bss)
+        end_of_bss = .;
+
+        . = ALIGN(4K);
+        *(.heap)
+    } :bss
+
+    /*
+        FIXME: 8MB is enough space for all of the tables required to identity map
+               physical memory. 8M is wasteful, so this should be properly calculated.
+    */
+
+    /* FIXME: Placeholder to satisfy linker */
+    start_of_unmap_after_init = .;
+    end_of_unmap_after_init = .;
+    start_of_ro_after_init = .;
+    end_of_ro_after_init = .;
+
+    . = ALIGN(4K);
+    page_tables_phys_start = .;
+
+    . += 8M;
+    page_tables_phys_end = .;
+
+    end_of_kernel_image = .;
+}

Kernel/CMakeLists.txt

@@ -713,7 +713,13 @@ add_dependencies(kernel_heap install_libc_headers)
 add_executable(Kernel ${SOURCES})
 add_dependencies(Kernel generate_EscapeSequenceStateMachine.h generate_version_header install_libc_headers)
 
-if (NOT "${SERENITY_ARCH}" STREQUAL "aarch64")
+if("${SERENITY_ARCH}" STREQUAL "aarch64")
+    target_link_options(Kernel PRIVATE LINKER:-T ${CMAKE_CURRENT_SOURCE_DIR}/Arch/aarch64/linker.ld -nostdlib LINKER:--no-pie)
+    set_target_properties(Kernel PROPERTIES LINK_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/Arch/aarch64/linker.ld)
+elseif("${SERENITY_ARCH}" STREQUAL "riscv64")
+    target_link_options(Kernel PRIVATE LINKER:-T ${CMAKE_CURRENT_SOURCE_DIR}/Arch/riscv64/linker.ld -nostdlib LINKER:--no-pie)
+    set_target_properties(Kernel PROPERTIES LINK_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/Arch/riscv64/linker.ld)
+elseif ("${SERENITY_ARCH}" STREQUAL "x86_64")
     add_custom_command(
         OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/linker.ld
         COMMAND "${CMAKE_CXX_COMPILER}" ${TARGET_STRING} -E -P -x c -I${CMAKE_CURRENT_SOURCE_DIR}/.. "${CMAKE_CURRENT_SOURCE_DIR}/Arch/x86_64/linker.ld" -o "${CMAKE_CURRENT_BINARY_DIR}/linker.ld"
@@ -730,9 +736,6 @@ if (NOT "${SERENITY_ARCH}" STREQUAL "aarch64")
     elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang$")
         target_compile_options(Kernel PRIVATE -mstack-alignment=8)
     endif()
-else()
-    target_link_options(Kernel PRIVATE LINKER:-T ${CMAKE_CURRENT_SOURCE_DIR}/Arch/aarch64/linker.ld -nostdlib LINKER:--no-pie)
-    set_target_properties(Kernel PROPERTIES LINK_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/Arch/aarch64/linker.ld)
 endif()
 
 if (ENABLE_KERNEL_LTO)