Implement proper .dynamic section parsing

crt0/switch_crt0.s

@@ -3,55 +3,39 @@
 
 _start:
     bl startup
-
-    .word 0x454d4f48
-    .word 0x57455242
+    .ascii "HOMEBREW"
 
 startup:
     // get aslr base
     sub  x28, x30, #4
 
     // clear .bss
-    ldr  x0, =__bss_start__
-    ldr  x1, =__bss_end__
+    adrp x0, __bss_start__
+    adrp x1, __bss_end__
+    add  x0, x0, #:lo12:__bss_start__
+    add  x1, x1, #:lo12:__bss_end__
     sub  x1, x1, x0  // calculate size
     add  x1, x1, #7  // round up to 8
     bic  x1, x1, #7
-    mov  x2, #0
-    add  x0, x0, x28 // relocate ptr
 
 bss_loop: 
-    str  x2, [x0], #8
+    str  xzr, [x0], #8
     subs x1, x1, #8
     bne  bss_loop
 
-    // relocate .got
-    ldr  x0, =__got_start__
-    ldr  x1, =__got_end__
-    sub  x1, x1, x0  // calculate size
-    add  x1, x1, #7  // round up to 8
-    bic  x1, x1, #7
-    add  x0, x0, x28 // relocate ptr
-
-got_loop: 
-    ldr  x2, [x0]
-    add  x2, x2, x28
-    str  x2, [x0], #8
-    subs x1, x1, #8
-    bne  got_loop
-
+    // process .dynamic section
     mov  x0, x28
-    ldr  x3, =initSystem
-    add  x3, x3, x28
-    blr  x3
+    adrp x1, _DYNAMIC
+    add  x1, x1, #:lo12:_DYNAMIC
+    bl   __nx_dynamic
 
+    // initialize system
+    mov  x0, x28
+    bl   __nx_init
+
+    // call entrypoint
     mov  x0, #0 // argc
     mov  x1, #0 // argv
-
-    ldr  x3, =main
-    add  x3, x3, x28
-    ldr  x2, =__nx_exit
-    add  x2, x2, x28
-    mov  x30, x2
-    br  x3
-
+    adrp x30, __nx_exit
+    add  x30, x30, #:lo12:__nx_exit
+    b    main

nx/source/system/dynamic.c

@@ -0,0 +1,37 @@
+#include <switch/types.h>
+#include <elf.h>
+
+void __nx_dynamic(uintptr_t base, const Elf64_Dyn* dyn)
+{
+	const Elf64_Rela* rela = NULL;
+	u64 relasz = 0;
+
+	for (; dyn->d_tag != DT_NULL; dyn++)
+	{
+		switch (dyn->d_tag)
+		{
+			case DT_RELA:
+				rela = (const Elf64_Rela*)(base + dyn->d_un.d_ptr);
+				break;
+			case DT_RELASZ:
+				relasz = dyn->d_un.d_val / sizeof(Elf64_Rela);
+				break;
+		}
+	}
+
+	if (rela == NULL)
+		for (;;); // Panic
+
+	for (; relasz--; rela++)
+	{
+		switch (ELF64_R_TYPE(rela->r_info))
+		{
+			case R_AARCH64_RELATIVE:
+			{
+				u64* ptr = (u64*)(base + rela->r_offset);
+				*ptr = base + rela->r_addend;
+				break;
+			}
+		}
+	}
+}

nx/source/system/sysinit.s

@@ -1,15 +1,12 @@
         .text
-	.global	initSystem
-	.type	initSystem,	%function
+	.global	__nx_init
+	.type	__nx_init, %function
 
-initSystem:
+__nx_init:
 	stp x29, x30, [sp, #-16]!
-        adr     x1, __nx_binarybase
-        str     x0, [x1]
 	bl	__libnx_init
-
 	bl	__appInit
-	bl	__nx_libc_init_array
+	bl	__libc_init_array
 	ldp x29, x30, [sp], #16
 	ret
 
@@ -17,83 +14,6 @@ initSystem:
 	.type	__nx_exit, %function
 
 __nx_exit:
-	bl	__nx_libc_fini_array
+	bl	__libc_fini_array
 	bl	__appExit
-
 	b	__libnx_exit
-
-__nx_libc_init_array:
-	stp x29, x30, [sp, #-16]!
-	stp x21, x22, [sp, #-16]!
-	stp x19, x20, [sp, #-16]!
-        adr     x3, __nx_binarybase
-        ldr     x20, [x3]
-
-        ldr     x0, =__preinit_array_start
-        ldr     x1, =__preinit_array_end
-        sub     x1, x1, x0
-        add     x21, x0, x20
-        lsr     x19, x1, #3
-        cbz     x19, __nx_libc_init_array_end0
-
-        __nx_libc_init_array_lp0:
-        ldr     x3, [x21], #8
-        sub     x19, x19, #1
-        add     x3, x3, x20
-        blr     x3
-        cbnz    x19, __nx_libc_init_array_lp0
-
-__nx_libc_init_array_end0:
-        bl      _init
-
-        ldr     x0, =__init_array_start
-        ldr     x1, =__init_array_end
-        sub     x1, x1, x0
-        add     x21, x0, x20
-        lsr     x19, x1, #3
-        cbz     x19, __nx_libc_init_array_end1
-
-        __nx_libc_init_array_lp1:
-        ldr     x3, [x21], #8
-        sub     x19, x19, #1
-        add     x3, x3, x20
-        blr     x3
-        cbnz    x19, __nx_libc_init_array_lp1
-
-__nx_libc_init_array_end1:
-	ldp x19, x20, [sp], #16
-	ldp x21, x22, [sp], #16
-	ldp x29, x30, [sp], #16
-        ret
-
-__nx_libc_fini_array:
-	stp x29, x30, [sp, #-16]!
-	stp x21, x22, [sp, #-16]!
-	stp x19, x20, [sp, #-16]!
-        adr     x3, __nx_binarybase
-        ldr     x20, [x3]
-
-        ldr     x0, =__fini_array_start
-        ldr     x1, =__fini_array_end
-        sub     x1, x1, x0
-        add     x21, x0, x20
-        lsr     x19, x1, #3
-        cbz     x19, __nx_libc_fini_array_end
-
-        __nx_libc_fini_array_lp:
-        sub     x19, x19, #1
-        ldr     x3, [x21, x19, lsl #3]
-        add     x3, x3, x20
-        blr     x3
-        cbnz    x19, __nx_libc_fini_array_lp
-
-__nx_libc_fini_array_end:
-	ldp x19, x20, [sp], #16
-	ldp x21, x22, [sp], #16
-	ldp x29, x30, [sp], #16
-        ret
-
-        .data
-__nx_binarybase:
-        .dword 0
-