Factor common userland and baremetal C functions

This allows add.c to run unmodified on both!

For that to work, use int main on baremetal, and pass the return value to
the final exit.

baremetal/add.c

@@ -1,6 +1,6 @@
 #include <common.h>
 
-void main(void) {
+int main(void) {
 	int i, j, k;
 	i = 1;
     /* test-gdb-op1 */
@@ -9,5 +9,5 @@ void main(void) {
 	k = i + j;
     /* test-gdb-result */
 	if (k != 3)
-		assert_fail();
+		common_assert_fail();
 }

baremetal/arch/aarch64/add.S

@@ -7,6 +7,6 @@ main:
     /* test-gdb-result */
     cmp x1, #3
     beq 1f
-    bl assert_fail
+    bl common_assert_fail
 1:
     ret

baremetal/arch/aarch64/fadd.S

@@ -12,7 +12,7 @@ main:
     fmov d3, #4.0
     fcmp d2, d3
     beq 1f
-    bl assert_fail
+    bl common_assert_fail
 1:
 
     /* Now in 32-bit. */
@@ -26,7 +26,7 @@ main:
     fmov s3, #4.0
     fcmp s2, s3
     beq 1f
-    bl assert_fail
+    bl common_assert_fail
 1:
 
     /* Higher registers. */
@@ -40,6 +40,6 @@ main:
     /* test-gdb-d31 */
     fcmp d30, d31
     beq 1f
-    bl assert_fail
+    bl common_assert_fail
 1:
     ret

baremetal/arch/arm/add.S

@@ -7,6 +7,6 @@ main:
     /* test-gdb-result */
     cmp r1, #3
     beq 1f
-    bl assert_fail
+    bl common_assert_fail
 1:
     bx lr

baremetal/exit.c

@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-void main(void) {
+int main(void) {
 	exit(0);
 }
 

baremetal/interactive/assert_fail.c

@@ -1,6 +1,6 @@
 #include <common.h>
 
-void main(void) {
-	assert_fail();
+int main(void) {
+	common_assert_fail();
 }
 

baremetal/interactive/exit1.c

@@ -1,6 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-void main(void) {
+int main(void) {
 	exit(1);
 }

baremetal/interactive/hello.c

@@ -1,5 +1,6 @@
 #include <stdio.h>
 
-void main(void) {
+int main(void) {
 	puts("hello");
+	return 0;
 }

baremetal/interactive/prompt.c

@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-void main(void) {
+int main(void) {
     char c;
     char *ptr = NULL;
     size_t alloc_size = 1;
@@ -19,4 +19,3 @@ void main(void) {
         }
     }
 }
-

baremetal/interactive/return1.c

@@ -0,0 +1 @@
+int main(void) { return 1; }

baremetal/lib/aarch64.S

@@ -8,5 +8,4 @@ mystart:
     ldr x0, =stack_top
     mov sp, x0
     bl main
-    mov x0, #0
     bl exit

baremetal/lib/arm.S

@@ -2,5 +2,4 @@
 mystart:
     ldr sp, =stack_top
     bl main
-    mov r0, #0
     bl exit

baremetal/lib/common.h

@@ -1,4 +0,0 @@
-#ifndef COMMON_H
-#define COMMON_H
-void assert_fail();
-#endif

baremetal/lib/syscalls.c

@@ -86,8 +86,3 @@ void _exit(int status) {
 #endif
 #endif
 }
-
-void assert_fail() {
-	puts("lkmc_test_fail");
-	exit(1);
-}

baremetal/return.c

@@ -1 +1 @@
-void main(void) {}
+int main(void) { return 0; }