xtensa: add support for NPTL

Changes from:
https://github.com/foss-xtensa/uClibc/commits/xtensa_nptl

Author: Chris Zankel <chris@zankel.net>
Author: Baruch Siach <baruch@tkos.co.il>

1 files changed, 55 insertions, 46 deletions

diff --git a/libc/sysdeps/linux/xtensa/clone.S b/libc/sysdeps/linux/xtensa/clone.S
index aa79aa736..34d68a875 100644
--- a/libc/sysdeps/linux/xtensa/clone.S
+++ b/libc/sysdeps/linux/xtensa/clone.S
@@ -1,34 +1,38 @@
-/* Copyright (C) 2001, 2005, 2007 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2005 Free Software Foundation, Inc.
 
    The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
 
    The GNU C Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
+   Library General Public License for more details.
 
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
 
 /* clone is even more special than fork as it mucks with stacks
-   and invokes a function in the right context after it's all over.  */
+   and invokes a function in the right context after its all over.  */
 
-#include "sysdep.h"
-#include <sys/syscall.h>
+#include <features.h>
+#include <sysdep.h>
 #define _ERRNO_H	1
 #include <bits/errno.h>
+#ifdef RESET_PID
+#include <tls.h>
+#endif
+#define __ASSEMBLY__
+#include <linux/sched.h>
 
-/* int clone (a2 = int (*fn)(void *arg),
-	      a3 = void *child_stack,
-	      a4 = int flags,
-	      a5 = void *arg,
-              a6 = pid_t *ptid,
-	      a7 = struct user_desc *tls,
-	      16(sp) = pid_t *ctid) */
+/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
+                    a2                    a3               a4        a5
+             pid_t *ptid, struct user_desc *tls, pid_t *ctid)
+                   a6               a7              16(sp)
+*/
 
         .text
 ENTRY (__clone)
@@ -39,7 +43,7 @@ ENTRY (__clone)
 
 	/* a2 and a3 are candidates for destruction by system-call return
 	   parameters.  We don't need the stack pointer after the system
-	   call.  We trust that the kernel will preserve a7, a9, and a6.  */
+	   call.  We trust that the kernel will preserve a6, a7 and a9. */
 
 	mov	a9, a5			/* save function argument */
 	mov	a5, a7
@@ -48,19 +52,18 @@ ENTRY (__clone)
 	mov	a6, a4
 	mov	a4, a8
 	l32i	a8, a1, 16		/* child_tid */
-	movi	a2, SYS_ify (clone)
-
-	/* syscall (a2 = NR_clone,
-		    a6 = clone_flags,
-		    a3 = usp,
-		    a4 = parent_tid,
-		    a5 = child_tls,
-		    a8 = child_tid) */
+	movi	a2, SYS_ify(clone)
+
+	/* syscall(NR_clone,clone_flags, usp, parent_tid, child_tls, child_tid)
+                     a2         a6        a3        a4        a5         a8
+         */
+
 	syscall
 	bltz	a2, SYSCALL_ERROR_LABEL
 	beqz	a2, .Lthread_start
 
-	/* Fall through for parent.  */
+	/* fall through for parent */
+
 .Lpseudo_end:
 	retw
 
@@ -69,32 +72,38 @@ ENTRY (__clone)
 	j	SYSCALL_ERROR_LABEL
 
 .Lthread_start:
-	/* Start child thread.  */
-	movi	a0, 0			/* terminate the stack frame */
+
+#if CLONE_THREAD != 0x00010000 || CLONE_VM != 0x00000100
+# error invalid values for CLONE_THREAD or CLONE_VM
+#endif
 
 #ifdef RESET_PID
-	/* Check and see if we need to reset the PID.  */
-	bbsi.l	a6, 16, 1f		/* CLONE_THREAD = 0x00010000 */
+	bbsi.l	a6, 16, .Lskip_restore_pid	/* CLONE_THREAD = 0x00010000 */
 	movi	a2, -1
-	bbsi.l	a6, 8, 2f		/* CLONE_VM = 0x00000100 */
-	movi	a2, SYS_ify (getpid)
+	bbsi	a6, 8, .Lgotpid			/* CLONE_VM     = 0x00000100 */
+	movi	a2, SYS_ify(getpid)
 	syscall
-2:	rur	a3, THREADPTR
-	movi	a4, PID_OFFSET
-	add	a4, a4, a3
-	s32i	a2, a4, 0
-	movi	a4, TID_OFFSET
-	add	a4, a4, a3
-	s32i	a2, a3, 0
-1:
-#endif /* RESET_PID */
-
+.Lgotpid:
+	rur	a3, threadptr
+	movi	a0, TLS_PRE_TCB_SIZE
+	sub	a3, a3, a0
+	s32i	a2, a3, PID
+	s32i	a2, a3, TID
+.Lskip_restore_pid:
+#endif
+
+	/* start child thread */
+	movi	a0, 0			/* terminate the stack frame */
 	mov	a6, a9			/* load up the 'arg' parameter */
 	callx4	a7			/* call the user's function */
 
 	/* Call _exit.  Note that any return parameter from the user's
-	   function in a6 is seen as inputs to _exit.  */
-	movi	a2, JUMPTARGET(_exit)
+	   function in a6 is seen as inputs to _exit. */
+#ifdef	PIC
+	movi	a2, _exit@PLT
+#else
+	movi	a2, _exit
+#endif
 	callx4	a2
 
 PSEUDO_END (__clone)