[klibc] [PATCH] Re: klibc barfs on m68k syscall interface

[Thorsten Glaser]

tag 334917 = patch
thanks

Hi,

I’ve fixed the m68k syscall of klibc and made it able to use
six-argument syscalls like mmap2. However, I could not yet
fully test it (only mostly; opendir() specifically fails) due
to: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47533

@m68k porters: Please have a look at the gcc bug as well.

@klibc: Please apply the patch, it’s better than what we have,
and (@packagers) with a binNMU it can be fixed once gcc works.

bye,
//mirabilos
-- 
22:20⎜<asarch> The crazy that persists in his craziness becomes a master
22:21⎜<asarch> And the distance between the craziness and geniality is
only measured by the success                       22:21⎜<mksh> it’s a
very thin line anyway… with some, you don’t know which side they’re on
-------------- next part --------------
diff -Nru klibc-1.5.21/debian/changelog klibc-1.5.21/debian/changelog
--- klibc-1.5.21/debian/changelog	2011-01-29 12:48:07.000000000 +0100
+++ klibc-1.5.21/debian/changelog	2011-01-29 15:48:04.000000000 +0100
@@ -1,3 +1,10 @@
+klibc (1.5.21-1+tg.2) unstable; urgency=low
+
+  * debian/patches/fix-m68k-syscalls: rewrite m68k syscall ABI
+    to fix it (Closes: #334917) and support 6-argument syscalls.
+
+ -- Thorsten Glaser <tg at mirbsd.de>  Sat, 29 Jan 2011 15:48:02 +0100
+
 klibc (1.5.21-1+tg.1) unstable; urgency=low
 
   * debian/patches/add-{arc4random,mkstemp}: add a minimalistic
diff -Nru klibc-1.5.21/debian/patches/fix-m68k-syscalls klibc-1.5.21/debian/patches/fix-m68k-syscalls
--- klibc-1.5.21/debian/patches/fix-m68k-syscalls	1970-01-01 01:00:00.000000000 +0100
+++ klibc-1.5.21/debian/patches/fix-m68k-syscalls	2011-01-29 15:47:18.000000000 +0100
@@ -0,0 +1,99 @@
+* Fix #334917 by rewriting the syscall API
+* Document this has been tested
+
+Index: klibc-1.5.21/usr/klibc/arch/m68k/syscall.S
+===================================================================
+--- klibc-1.5.21.orig/usr/klibc/arch/m68k/syscall.S	2011-01-29 13:28:39.000000000 +0100
++++ klibc-1.5.21/usr/klibc/arch/m68k/syscall.S	2011-01-29 15:47:09.000000000 +0100
+@@ -11,17 +11,47 @@
+ 	.globl	__syscall_common
+ 	.type	__syscall_common, @function
+ __syscall_common:
+-	movem.l %d2-%d6, -(%sp)	/* 5 registers saved */
+-	movem.l	24(%sp), %d1-%d6
++#if 0
++	/* debugging: define "int32_t last_syscall;" in your code... */
++	move.l	%d0, (last_syscall)	/* to see which is actually run */
++#endif
++	/*
++	 * According to eglibc, separate moves are faster than movem;
++	 * speed is important and this code is not duplicated anyway,
++	 * so we do the same here. We use %a1 as scratch register for
++	 * saving; syscall arguments are to be in %d1 to %d5 and %a0.
++	 */
++	move.l	24(%sp), %a0		/* orig.sp+24: arg 6 */
++	move.l	%d5, -(%sp)		/* push d5 (callee saved) */
++	move.l	24(%sp), %d5		/* orig.sp+20: arg 5 */
++	move.l	%d4, -(%sp)		/* push d4 (callee saved) */
++	move.l	24(%sp), %d4		/* orig.sp+16: arg 4 */
++	move.l	%d3, -(%sp)		/* push d3 (callee saved) */
++	move.l	24(%sp), %d3		/* orig.sp+12: arg 3 */
++	move.l	%d2, %a1		/* save d2 (callee saved) in a1 */
++	move.l	20(%sp), %d2		/* orig.sp+8:  arg 2 */
++	move.l	16(%sp), %d1		/* orig.sp+4:  arg 1 */
+ 	trap	#0
+-	cmpi.l	#-4095, %d0
+-	blt.l	1f
++	move.l	%a1, %d2		/* restore d2 from a1 (scratch) */
++	move.l	(%sp)+, %d3		/* pop d3..d5, see above */
++	move.l	(%sp)+, %d4
++	move.l	(%sp)+, %d5
++
++	/* syscall is done, result in %d0, registers are restored */
++	.globl	__syscall_checkandout
++__syscall_checkandout:
++	/* now check for error */
++	cmp.l	#-4095, %d0
++	bcs.l	1f			/* jmp short if _not_ error */
++
++	/* prepare for error return */
+ 	neg.l	%d0
+ 	move.l	%d0, (errno)
+-	moveq	#-1, %d0
+-1:
+-	movea.l	%d0, %a0	/* Redundant return */
+-	movem.l (%sp)+, %d2-%d6 /* Restore registers */
++	move.l	#-1, %d0
++	/* fallthrough to common return path */
++
++1:	/* copy return value to %a0 for syscalls returning pointers */
++	move.l	%d0, %a0
+ 	rts
+ 
+ 	.size	__syscall_common,.-__syscall_common
+Index: klibc-1.5.21/usr/klibc/README.klibc
+===================================================================
+--- klibc-1.5.21.orig/usr/klibc/README.klibc	2011-01-29 14:49:53.000000000 +0100
++++ klibc-1.5.21/usr/klibc/README.klibc	2011-01-29 14:53:57.000000000 +0100
+@@ -44,7 +44,7 @@
+    i386:	 Working
+    ia64:	 Working static, shared untested
+    m32r:	 Untested
+-   m68k:	 Untested
++   m68k:	 Working
+    m68knommu:	 Not yet ported
+    mips:	 Working
+    mips64:	 Not yet ported
+Index: klibc-1.5.21/usr/klibc/arch/m68k/vfork.S
+===================================================================
+--- klibc-1.5.21.orig/usr/klibc/arch/m68k/vfork.S	2011-01-29 14:47:11.000000000 +0100
++++ klibc-1.5.21/usr/klibc/arch/m68k/vfork.S	2011-01-29 15:28:51.000000000 +0100
+@@ -15,14 +15,9 @@
+ 	move.l	(%sp)+, %d1		/* Return address */
+ 	move.l	# __NR_vfork, %d0
+ 	trap	#0
+-	move.l	%d1, -(%sp)
+-	cmpi.l	#-4095, %d0
+-	blt.l	1f
+-	neg.l	%d0
+-	move.l	%d0, (errno)
+-	moveq	#-1, %d0
+-1:
+-	movea.l	%d0, %a0
+-	rts
++	move.l	%d1, -(%sp)		/* restore stack */
++
++	/* common code from syscall.S */
++	bra	__syscall_checkandout
+ 
+ 	.size	vfork, .-vfork
diff -Nru klibc-1.5.21/debian/patches/series klibc-1.5.21/debian/patches/series
--- klibc-1.5.21/debian/patches/series	2011-01-29 12:48:07.000000000 +0100
+++ klibc-1.5.21/debian/patches/series	2011-01-29 13:28:34.000000000 +0100
@@ -4,3 +4,4 @@
 debian-changes-1.5.21-1
 add-arc4random
 add-mkstemp
+fix-m68k-syscalls