ch1:First instruction in kernel

.cargo/config.toml

@@ -1,2 +1,7 @@
 [build]
-target = "riscv64gc-unknown-none-elf"
+target = "riscv64gc-unknown-none-elf"
+
+[target.riscv64gc-unknown-none-elf]
+rustflags = [
+    "-Clink-arg=-Tsrc/linker.ld", "-Cforce-frame-pointers=yes"
+]

src/entry.asm

@@ -0,0 +1,4 @@
+    .section .text.entry
+    .globl _start
+_start:
+    li x1, 100

src/linker.ld

@@ -0,0 +1,48 @@
+OUTPUT_ARCH(riscv)
+ENTRY(_start)
+BASE_ADDRESS = 0x80200000;
+
+SECTIONS
+{
+    . = BASE_ADDRESS;
+    skernel = .;
+
+    stext = .;
+    .text : {
+        *(.text.entry)
+        *(.text .text.*)
+    }
+
+    . = ALIGN(4K);
+    etext = .;
+    srodata = .;
+    .rodata : {
+        *(.data .rodata.*)
+        *(.srodata .srodata.*)
+    }
+
+    . = ALIGN(4K);
+    erodata = .;
+    sdata = .;
+    .data : {
+        *(.data .data.*)
+        *(.sdata .sdata.*)
+    }
+
+    . = ALIGN(4K);
+    edata = .;
+    .bss : {
+        *(.bss.stack)
+        sbss = .;
+        *(.bss .bss.*)
+        *(.sbss .sbss.*)
+    }
+
+    . = ALIGN(4K);
+    ebss = .;
+    ekernel = .;
+     
+    /DISCARD/ : {
+        *(.eh_frame)
+    }
+}

src/main.rs

@@ -2,3 +2,6 @@
 #![no_main]
 
 mod lang_items;
+
+use core::arch::global_asm;
+global_asm!(include_str!("entry.asm"));