This commit contains a patch from Stefan Allius <allius@atecom.com> to change

how uClibc handles _init and _fini, allowing shared lib constructors and
destructors to initialize things in the correct sequence.  Stefan ported the SH
architecture.  I then ported x86, arm, and mips.  x86 and arm are working fine,
but I don't think I quite got things correct for mips.

4 files changed, 72 insertions, 49 deletions

diff --git a/libc/sysdeps/linux/arm/crt0.S b/libc/sysdeps/linux/arm/crt0.S
index 442c9e84b..dc0ec87d8 100644
--- a/libc/sysdeps/linux/arm/crt0.S
+++ b/libc/sysdeps/linux/arm/crt0.S
@@ -50,20 +50,10 @@ ARM register quick reference:
 
 .text
 	.global _start
-	.global __uClibc_main
-
 	.type   _start,%function
-	.type   __uClibc_main,%function
 
 .text
 _start:
-#if 0 /* some old code the I feel should not be here - davidm */
-	@ adjust the data segment base pointer
-	ldr r3,=__data_start
-	sub sl,sl,r3
-	mov BASEREG,sl
-#endif
-
 	/* clear the frame pointer */
 	mov     fp, #0
 
@@ -78,10 +68,11 @@ _start:
 	   we find there (hopefully the environment) in r2 */
 	add     r2, r1, r0, lsl #2
 	add     r2, r2, #4
+
 #else
 	/*
-	 * uClinux stacks look a little different to MMU stacks
-	 * for no good reason
+	 * uClinux stacks look a little different from normal
+	 * MMU-full Linux stacks (for no good reason)
 	 */
 	/* pull argc, argv and envp off the stack */
 	ldr r0,[sp, #0]
@@ -89,8 +80,19 @@ _start:
 	ldr r2,[sp, #8]
 #endif
 
+	/* Store the address of _init in r3 as an argument to main() */
+	ldr r3, =_init
+
+	/* Push _fini onto the stack as the final argument to main() */
+	stmfd sp!, {r0}
+	ldr a1, =_fini
+	stmfd sp!, {r0}
+
 	/* Ok, now run uClibc's main() -- shouldn't return */
-	bl	__uClibc_main
+	bl	__uClibc_start_main
+
+	/* Crash if somehow `exit' returns anyways.  */
+	bl abort
 
 /* Stick in a dummy reference to main(), so that if an application
  * is linking when the main() function is in a static library (.a)
diff --git a/libc/sysdeps/linux/i386/crt0.S b/libc/sysdeps/linux/i386/crt0.S
index 3623fe821..97f1fde63 100644
--- a/libc/sysdeps/linux/i386/crt0.S
+++ b/libc/sysdeps/linux/i386/crt0.S
@@ -33,11 +33,11 @@ Cambridge, MA 02139, USA.  */
 .text
 	.align 4
 
-.globl _start
-	.type	 _start,@function
+	.globl _start
+	.type _start,@function
 
 _start:
-	/* First locate the start of the environment variables */
+	/* locate the start of the environment variables */
 	popl %ecx	/* Store argc into %ecx */
 	movl %esp,%ebx  /* Store argv into ebx */
 	movl %esp,%eax  /* Store argv into eax as well*/
@@ -52,7 +52,6 @@ _start:
 	    %eax = env	    ; argv + (argc * 4) + 4
 	*/
 
-
 	/* Set up an invalid (NULL return address, NULL frame pointer)
 	   callers stack frame so anybody unrolling the stack knows where
 	   to stop */
@@ -62,20 +61,18 @@ _start:
 	pushl %ebp      /* callers %ebp (frame pointer) */
 	movl %esp,%ebp  /* mark callers stack frame as invalid */
 
-	/* Now set the environment, argc, and argv where the app can get to them */
-	pushl %eax      /* Environment pointer */
-	pushl %ebx       /* Argument pointer */
-	pushl %ecx      /* And the argument count */
+	/* Push .init and .fini arguments to __uClibc_start_main() on the stack */
+	pushl $_fini
+	pushl $_init
 
-#if 0
-	/* Make sure we are not using iBCS2 personality. (i.e. force linux).  */
-	movl $136,%eax
-	sub %ebx,%ebx
-	int $0x80
-#endif
+	/* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */ 
+	pushl %eax	/* Environment pointer */
+	pushl %ebx	/* Argument pointer */
+	pushl %ecx	/* And the argument count */
 
 	/* Ok, now run uClibc's main() -- shouldn't return */
-	call __uClibc_main
+	call __uClibc_start_main
+
 	/* Crash if somehow `exit' returns anyways.  */
 	hlt
 
diff --git a/libc/sysdeps/linux/mips/crt0.S b/libc/sysdeps/linux/mips/crt0.S
index 6770ab0b1..7ff3b253f 100644
--- a/libc/sysdeps/linux/mips/crt0.S
+++ b/libc/sysdeps/linux/mips/crt0.S
@@ -30,9 +30,22 @@ __start:
 	addu a2, a0, 1	    /* load envp */
         sll  a2, a2, 2
 	add  a2, a2, a1
+
+	/* Store the address of _init in a3 as an argument to __uClibc_start_main() */
+	la   a3, _init
+
+	/* Push _fini onto the stack as the final argument to __uClibc_start_main()
+	    I don't think I am doing this properly but it at least compiles... 
+	*/
+	la   t0, _fini
+	sw   t0,16(sp)
+	
 	/* Ok, now run uClibc's main() -- shouldn't return */
-	jal	__uClibc_main
-	hlt:    b hlt                   /* Crash if somehow it does return.  */
+	jal  __uClibc_start_main
+
+	/* Crash if somehow `exit' returns anyways.  */
+hlt:
+	b   hlt
 
 /* Stick in a dummy reference to main(), so that if an application
  * is linking when the main() function is in a static library (.a)
diff --git a/libc/sysdeps/linux/sh/crt0.S b/libc/sysdeps/linux/sh/crt0.S
index 10915d545..e74ae86c4 100644
--- a/libc/sysdeps/linux/sh/crt0.S
+++ b/libc/sysdeps/linux/sh/crt0.S
@@ -26,13 +26,6 @@
 
 	At this entry point, most registers' values are unspecified, except:
 
-   r4		Contains a function pointer to be registered with `atexit'.
-   		This is how the dynamic linker arranges to have DT_FINI
-		functions called for shared libraries that have been loaded
-		before this code runs.
-		WARNING: At that stage only static linker is supported. For
-		uCLinux we won't bother with r4.
-
    sp		The stack contains the arguments and environment:
    		0(sp)			argc
 		4(sp)			argv[0]
@@ -42,18 +35,26 @@
 		...
 					NULL
 */
+	.file "crt0.S"
 	.text
 	.globl _start
 	.type _start,@function
 	.size _start,_start_end - _start
 _start:
-	/* Clear the frame pointer since this is the outermost frame. (in delay slot) */
+	/* Clear the frame pointer since this is the outermost frame. */
 	mov #0, r14
 
 	/* Pop argc off the stack and save a pointer to argv */
 	mov.l @r15+,r4
 	mov r15, r5
 
+	/* Push the finip argument to __uClibc_start_main() onto the stack */
+	mov.l L_fini,r6
+	mov.l r6,@-r15
+
+	/* Setup the value for the initp argument */
+	mov.l L_init, r7
+
 	/*
 	 * Setup the value for the environment pointer:
 	 * r6 = (argc + 1) * 4
@@ -62,27 +63,39 @@ _start:
 	mov r4,r6
 	add #1,r6
 	shll2 r6
-	add r5,r6
 
-	/* call main */
+	/* jump to __uClibc_start_main (argc, argv, envp, app_init, app_fini) */
 	mov.l L_main, r0
 	jsr @r0
-	nop /* delay slot */
-
+	add r5, r6  /* delay slot */
 	/* We should not get here. */
 	mov.l L_abort, r0
-	jsr @r0
-	nop /* delay slot */
+	jmp @r0
+	nop
 
 _start_end:	
 	.align	2
 
+	.weak   _init
+	.type   _init,@function
+_init:
+	rts
+	nop
+
+.Lfe1:
+	.size   _init,.Lfe1-_init
+	.weak   _fini
+	.set    _fini,_init
 
 L_main:
-	.long	__uClibc_main
+	.long   __uClibc_start_main /* in libuClibc.*.so */
 
-L_abort:
-	.long	abort
+L_init:
+      .long   _init
+L_fini:
+      .long   _fini
+L_abort: 
+      .long   abort   
 
 /* Stick in a dummy reference to main(), so that if an application
  * is linking when the main() function is in a static library (.a)
@@ -90,5 +103,3 @@ L_abort:
 L_dummy_main_reference:
 	.long	main
 
-	.data
-