Split shared ld_so code and actual ld_so stubs.

2024-05-01 13:17:20 +02:00
parent 73952b69ed
commit 326c8a6231
8 changed files with 5 additions and 5 deletions
@@ -0,0 +1,82 @@
+#![no_std]
+#![feature(linkage)]
+
+use core::arch::global_asm;
+
+#[cfg(target_arch = "aarch64")]
+global_asm!(
+    "
+.globl _start
+_start:
+    mov x0, sp
+    and sp, x0, #0xfffffffffffffff0 //align sp
+    bl relibc_ld_so_start
+    # TODO: aarch64
+    udf #0
+"
+);
+
+#[cfg(target_arch = "x86")]
+global_asm!(
+    "
+.globl _start
+_start:
+    push esp
+    call relibc_ld_so_start
+    pop esp
+    # TODO: x86
+    ud2
+"
+);
+
+#[cfg(target_arch = "x86_64")]
+global_asm!(
+    "
+.globl _start
+_start:
+    # rsi = _start + 5
+    call 2f
+2:  pop rsi
+
+    # Save original stack and align stack to 16 bytes
+    mov rbp, rsp
+    and rsp, 0xFFFFFFFFFFFFFFF0
+
+    # Call ld_so_start(stack, entry)
+    mov rdi, rbp
+    sub rsi, 5
+    call relibc_ld_so_start
+
+    # Restore original stack, clear registers, and jump to new start function
+    mov rsp, rbp
+    xor rcx, rcx
+    xor rdx, rdx
+    xor rdi, rdi
+    xor rsi, rsi
+    xor r8, r8
+    xor r9, r9
+    xor r10, r10
+    xor r11, r11
+    fninit
+    jmp rax
+"
+);
+
+#[no_mangle]
+pub unsafe extern "C" fn main(_argc: isize, _argv: *const *const i8) -> usize {
+    // LD
+    0x1D
+}
+
+#[linkage = "weak"]
+#[no_mangle]
+extern "C" fn relibc_panic(pi: &::core::panic::PanicInfo) -> ! {
+    loop {}
+}
+
+#[panic_handler]
+#[linkage = "weak"]
+#[no_mangle]
+pub unsafe fn rust_begin_unwind(pi: &::core::panic::PanicInfo) -> ! {
+    relibc_panic(pi)
+}