"TLS-lite": add kernel support for a per-thread userspace pointer,

for pointing to the thread-control-block.  Support for mapping this
to the correct hardware register can be added as it's finished;
start with support for amd64, sparc, and sparc64.  Includes syscalls
for getting and setting it (for a portable __errno implementation) as
well as creating a new thread with an initial value for it.

discussed with miod@, kettenis@, deraadt@; committing to get the syscalls
in with the impending libc bump and do further refinements in tree

11 files changed, 317 insertions, 12 deletions

diff --git a/sys/arch/amd64/include/proc.h b/sys/arch/amd64/include/proc.h
index b56cdb7e50f..733c93ea5cc 100644
--- a/sys/arch/amd64/include/proc.h
+++ b/sys/arch/amd64/include/proc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.6 2011/03/23 16:54:34 pirofti Exp $	*/
+/*	$OpenBSD: proc.h,v 1.7 2011/10/15 23:35:29 guenther Exp $	*/
 /*	$NetBSD: proc.h,v 1.1 2003/04/26 18:39:46 fvdl Exp $	*/
 
 /*
@@ -35,11 +35,10 @@
 #ifndef _MACHINE_PROC_H_
 #define _MACHINE_PROC_H_
 
-#include <machine/frame.h>
-
 /*
  * Machine-dependent part of the proc structure for amd64.
  */
+struct trapframe;
 struct mdproc {
 	struct	trapframe *md_regs;	/* registers on current frame */
 	int	md_flags;
@@ -49,5 +48,8 @@ struct mdproc {
 /* md_flags */
 #define	MDP_USEDFPU	0x0001	/* has used the FPU */
 #define MDP_IRET	0x0002	/* return via iret, not sysret */
+				/* (iret can restore r11 and rcx) */
+
+#define __HAVE_MD_TCB
 
 #endif /* _MACHINE_PROC_H_ */
diff --git a/sys/arch/amd64/include/tcb.h b/sys/arch/amd64/include/tcb.h
new file mode 100644
index 00000000000..f6a0ed87a7f
--- /dev/null
+++ b/sys/arch/amd64/include/tcb.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2011 Philip Guenther <guenther@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _MACHINE_TCB_H_
+#define _MACHINE_TCB_H_
+
+#ifdef _KERNEL
+
+#include <machine/pcb.h>
+
+#define TCB_GET(p)		\
+	((void *)((struct pcb *)(p)->p_addr)->pcb_fsbase)
+#define TCB_SET(p, addr)	\
+	(((struct pcb *)(p)->p_addr)->pcb_fsbase = (u_int64_t)(addr))
+
+#else /* _KERNEL */
+
+#include <stddef.h>		/* for offsetof */
+
+/* ELF TLS ABI calls for big TCB, with static TLS data at negative offsets */
+#define TLS_VARIANT	2
+
+/* Read a slot from the TCB */
+static inline void *
+__amd64_read_tcb(long offset)
+{
+	void	*val;
+	__asm__ ("movq %%fs:(%1),%0" : "=r" (val) : "r" (offset));
+	return val;
+}
+
+/* Get a pointer to the TCB itself */
+#define TCB_GET()		__amd64_read_tcb(0)
+
+/* Get the value of a specific member in the TCB */
+#define TCB_GET_MEMBER(member)	\
+	__amd64_read_tcb(offsetof(struct thread_control_block, member))
+
+/* Setting the TCB pointer can only be done via syscall, so no TCB_SET() */
+
+#endif /* _KERNEL */
+
+#endif /* _MACHINE_TCB_H_ */
diff --git a/sys/arch/sparc/include/proc.h b/sys/arch/sparc/include/proc.h
index 419d945ac75..d8d5f867904 100644
--- a/sys/arch/sparc/include/proc.h
+++ b/sys/arch/sparc/include/proc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.4 2010/11/27 19:41:45 miod Exp $	*/
+/*	$OpenBSD: proc.h,v 1.5 2011/10/15 23:35:29 guenther Exp $	*/
 /*	$NetBSD: proc.h,v 1.3 1996/09/26 18:51:17 christos Exp $ */
 
 /*
@@ -48,3 +48,5 @@ struct mdproc {
 	struct	trapframe *md_tf;	/* trap/syscall registers */
 	struct	fpstate *md_fpstate;	/* fpu state, if any; always resident */
 };
+
+#define	__HAVE_MD_TCB
diff --git a/sys/arch/sparc/include/tcb.h b/sys/arch/sparc/include/tcb.h
new file mode 100644
index 00000000000..b445918b925
--- /dev/null
+++ b/sys/arch/sparc/include/tcb.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2011 Philip Guenther <guenther@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _MACHINE_TCB_H_
+#define _MACHINE_TCB_H_
+
+#ifdef _KERNEL
+
+#include <machine/reg.h>
+
+/*
+ * In userspace, register %g7 contains the address of the thread's TCB
+ */
+#define TCB_GET(p)		\
+	((void *)(p)->p_md.md_tf->tf_global[7])
+#define TCB_SET(p, addr)	\
+	((p)->p_md.md_tf->tf_global[7] = (int)(addr))
+
+#else /* _KERNEL */
+
+/* ELF TLS ABI calls for big TCB, with static TLS data at negative offsets */
+#define TLS_VARIANT	2
+
+#if 0	/* XXX perhaps use the gcc global register extension? */
+struct thread_control_block;
+__register__ struct thread_control_block *__tcb __asm__ ("%g7");
+#define TCB_GET()		(__tcb)
+#define TCB_GET_MEMBER(member)	((void *)(__tcb->member))
+#define TCB_SET(tcb)		((__tcb) = (tcb))
+
+#else
+
+#include <stddef.h>		/* for offsetof */
+
+/* Get a pointer to the TCB itself */
+static inline void *
+__sparc_get_tcb(void)
+{
+	void *val;
+	__asm__ ("mov %%g7, %0" : "=r" (val));
+	return val;
+}
+#define TCB_GET()		__sparc_get_tcb()
+
+/* Get the value of a specific member in the TCB */
+static inline void *
+__sparc_get_tcb(int offset)
+{
+	void	*val;
+	__asm__ ("ld [%%g7 + %1], %0" : "=r" (val) : "r" (offset));
+	return val;
+}
+#define TCB_GET_MEMBER(member)	\
+	__sparc_get_tcb(offsetof(struct thread_control_block, member))
+
+#define TCB_SET(tcb)	(__asm __volatile("mov %0, %%g7" : : "r" (tcb)))
+
+#endif /* 0 */
+
+#endif /* _KERNEL */
+
+#endif /* _MACHINE_TCB_H_ */
diff --git a/sys/arch/sparc64/include/proc.h b/sys/arch/sparc64/include/proc.h
index 0559c74bcc9..6ae7daa48d7 100644
--- a/sys/arch/sparc64/include/proc.h
+++ b/sys/arch/sparc64/include/proc.h
@@ -48,3 +48,5 @@ struct mdproc {
 	struct	fpstate64 *md_fpstate;	/* fpu state, if any; always resident */
 	__volatile int md_astpending;
 };
+
+#define	__HAVE_MD_TCB
diff --git a/sys/arch/sparc64/include/tcb.h b/sys/arch/sparc64/include/tcb.h
new file mode 100644
index 00000000000..6dedb858c05
--- /dev/null
+++ b/sys/arch/sparc64/include/tcb.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2011 Philip Guenther <guenther@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _MACHINE_TCB_H_
+#define _MACHINE_TCB_H_
+
+#ifdef _KERNEL
+
+#include <machine/reg.h>
+
+/*
+ * In userspace, register %g7 contains the address of the thread's TCB
+ */
+#define TCB_GET(p)		\
+	((void *)(p)->p_md.md_tf->tf_global[7])
+#define TCB_SET(p, addr)	\
+	((p)->p_md.md_tf->tf_global[7] = (int64_t)(addr))
+
+#else /* _KERNEL */
+
+/* ELF TLS ABI calls for big TCB, with static TLS data at negative offsets */
+#define TLS_VARIANT	2
+
+#if 0	/* XXX perhaps use the gcc global register extension? */
+struct thread_control_block;
+__register__ struct thread_control_block *__tcb __asm__ ("%g7");
+#define TCB_GET()		(__tcb)
+#define TCB_GET_MEMBER(member)	((void *)(__tcb->member))
+#define TCB_SET(tcb)		((__tcb) = (tcb))
+
+#else
+
+#include <stddef.h>		/* for offsetof */
+
+/* Get a pointer to the TCB itself */
+static inline void *
+__sparc64_get_tcb(void)
+{
+	void *val;
+	__asm__ ("mov %%g7, %0" : "=r" (val));
+	return val;
+}
+#define TCB_GET()		__sparc64_get_tcb()
+
+/* Get the value of a specific member in the TCB */
+static inline void *
+__sparc64_get_tcb(int offset)
+{
+	void	*val;
+	__asm__ ("ldx [%%g7 + %1], %0" : "=r" (val) : "r" (offset));
+	return val;
+}
+#define TCB_GET_MEMBER(member)	\
+	__sparc64_get_tcb(offsetof(struct thread_control_block, member))
+
+#define TCB_SET(tcb)	(__asm __volatile("mov %0, %%g7" : : "r" (tcb)))
+
+#endif /* 0 */
+
+#endif /* _KERNEL */
+
+#endif /* _MACHINE_TCB_H_ */
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 59334cfdd03..39c2249638b 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_fork.c,v 1.128 2011/07/07 18:00:33 guenther Exp $	*/
+/*	$OpenBSD: kern_fork.c,v 1.129 2011/10/15 23:35:29 guenther Exp $	*/
 /*	$NetBSD: kern_fork.c,v 1.29 1996/02/09 18:59:34 christos Exp $	*/
 
 /*
@@ -65,12 +65,17 @@
 #include <uvm/uvm_extern.h>
 #include <uvm/uvm_map.h>
 
+#ifdef __HAVE_MD_TCB
+# include <machine/tcb.h>
+#endif
+
 int	nprocs = 1;		/* process 0 */
 int	randompid;		/* when set to 1, pid's go random */
 pid_t	lastpid;
 struct	forkstat forkstat;
 
 void fork_return(void *);
+void tfork_child_return(void *);
 int pidtaken(pid_t);
 
 void process_new(struct proc *, struct proc *);
@@ -148,6 +153,39 @@ sys_rfork(struct proc *p, void *v, register_t *retval)
 	return (fork1(p, SIGCHLD, flags, NULL, 0, NULL, NULL, retval, NULL));
 }
 
+int
+sys___tfork(struct proc *p, void *v, register_t *retval)
+{
+	struct sys___tfork_args /* {
+		syscallarg(struct __tfork) *param;
+	} */ *uap = v;
+	struct __tfork param;
+	int flags;
+	int error;
+
+	if ((error = copyin(SCARG(uap, param), &param, sizeof(param))))
+		return (error);
+
+	/* XXX will supersede rfork at some point... */
+	if (param.tf_flags != 0)
+		return (EINVAL);
+
+	flags = FORK_TFORK | FORK_THREAD | FORK_SIGHAND | FORK_SHAREVM
+	    | FORK_NOZOMBIE | FORK_SHAREFILES;
+
+	return (fork1(p, 0, flags, NULL, param.tf_tid, tfork_child_return,
+	    param.tf_tcb, retval, NULL));
+}
+
+void
+tfork_child_return(void *arg)
+{
+	struct proc *p = curproc;
+
+	TCB_SET(p, arg);
+	child_return(p);
+}
+
 /*
  * Allocate and initialize a new process.
  */
@@ -196,7 +234,7 @@ process_new(struct proc *newproc, struct proc *parentproc)
 struct timeval fork_tfmrate = { 10, 0 };
 
 int
-fork1(struct proc *p1, int exitsig, int flags, void *stack, size_t stacksize,
+fork1(struct proc *p1, int exitsig, int flags, void *stack, pid_t *tidptr,
     void (*func)(void *), void *arg, register_t *retval,
     struct proc **rnewprocp)
 {
@@ -364,7 +402,7 @@ fork1(struct proc *p1, int exitsig, int flags, void *stack, size_t stacksize,
 	 * different path later.
 	 */
 	uvm_fork(p1, p2, ((flags & FORK_SHAREVM) ? TRUE : FALSE), stack,
-	    stacksize, func ? func : child_return, arg ? arg : p2);
+	    0, func ? func : child_return, arg ? arg : p2);
 
 	timeout_set(&p2->p_stats->p_virt_to, virttimer_trampoline, p2);
 	timeout_set(&p2->p_stats->p_prof_to, proftimer_trampoline, p2);
@@ -377,6 +415,10 @@ fork1(struct proc *p1, int exitsig, int flags, void *stack, size_t stacksize,
 	} else if (flags & FORK_VFORK) {
 		forkstat.cntvfork++;
 		forkstat.sizvfork += vm->vm_dsize + vm->vm_ssize;
+#if 0
+	} else if (flags & FORK_TFORK) {
+		forkstat.cnttfork++;
+#endif
 	} else if (flags & FORK_RFORK) {
 		forkstat.cntrfork++;
 		forkstat.sizrfork += vm->vm_dsize + vm->vm_ssize;
@@ -425,6 +467,13 @@ fork1(struct proc *p1, int exitsig, int flags, void *stack, size_t stacksize,
 		systrace_fork(p1, p2, newstrp);
 #endif
 
+	if (tidptr != NULL) {
+		pid_t	pid = p2->p_pid + THREAD_PID_OFFSET;
+
+		if (copyout(&pid, tidptr, sizeof(pid)))
+			psignal(p1, SIGSEGV);
+	}
+
 	/*
 	 * Make child runnable, set start time, and add to run queue.
 	 */
diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c
index 1a0f724db41..e936e44970e 100644
--- a/sys/kern/kern_prot.c
+++ b/sys/kern/kern_prot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_prot.c,v 1.50 2011/07/25 20:32:06 tedu Exp $	*/
+/*	$OpenBSD: kern_prot.c,v 1.51 2011/10/15 23:35:29 guenther Exp $	*/
 /*	$NetBSD: kern_prot.c,v 1.33 1996/02/09 18:59:42 christos Exp $	*/
 
 /*
@@ -54,6 +54,10 @@
 #include <sys/mount.h>
 #include <sys/syscallargs.h>
 
+#ifdef	__HAVE_MD_TCB
+# include <machine/tcb.h>
+#endif
+
 /* ARGSUSED */
 int
 sys_getpid(struct proc *p, void *v, register_t *retval)
@@ -890,3 +894,27 @@ proc_cansugid(struct proc *p)
 	/* Allow. */
 	return (1);
 }
+
+/*
+ * Set address of the proc's thread-control-block
+ */
+int
+sys___set_tcb(struct proc *p, void *v, register_t *retval)
+{
+	struct sys___set_tcb_args /* {
+		syscallarg(void *) tcb;
+	} */ *uap = v;
+
+	TCB_SET(p, SCARG(uap, tcb));
+	return (0);
+}
+
+/*
+ * Get address of the proc's thread-control-block
+ */
+int
+sys___get_tcb(struct proc *p, void *v, register_t *retval)
+{
+	*retval = (register_t)TCB_GET(p);
+	return (0);
+}
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index cd4a7899bcb..c8011d97d42 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -1,4 +1,4 @@
-;	$OpenBSD: syscalls.master,v 1.118 2011/07/18 00:16:54 matthew Exp $
+;	$OpenBSD: syscalls.master,v 1.119 2011/10/15 23:35:29 guenther Exp $
 ;	$NetBSD: syscalls.master,v 1.32 1996/04/23 10:24:21 mycroft Exp $
 
 ;	@(#)syscalls.master	8.2 (Berkeley) 1/13/94
@@ -574,3 +574,6 @@
 			    const struct timespec *times, int flag); }
 327	STD		{ int sys_futimens(int fd, \
 			    const struct timespec *times); }
+328	STD		{ int sys___tfork(struct __tfork *param); }
+329	STD NOLOCK	{ void sys___set_tcb(void *tcb); }
+330	STD NOLOCK	{ void *sys___get_tcb(void); }
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 3a4aa490181..bc2a43962d8 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.143 2011/09/20 10:07:37 deraadt Exp $	*/
+/*	$OpenBSD: proc.h,v 1.144 2011/10/15 23:35:29 guenther Exp $	*/
 /*	$NetBSD: proc.h,v 1.44 1996/04/22 01:23:21 christos Exp $	*/
 
 /*-
@@ -235,6 +235,11 @@ struct proc {
 	long 	p_thrslpid;	/* for thrsleep syscall */
 	int	p_sigwait;	/* signal handled by sigwait() */
 
+#ifndef	__HAVE_MD_TCB
+	void	*p_tcb;		/* user-space thread-control-block address */
+# define TCB_SET(p, addr)	((p)->p_tcb = (addr))
+# define TCB_GET(p)		((p)->p_tcb)
+#endif
 
 	/* scheduling */
 	u_int	p_estcpu;	 /* Time averaged value of p_cpticks. */
@@ -425,6 +430,7 @@ struct uidinfo *uid_find(uid_t);
 #define FORK_CLEANFILES	0x00000020
 #define FORK_NOZOMBIE	0x00000040
 #define FORK_SHAREVM	0x00000080
+#define FORK_TFORK	0x00000100
 #define FORK_SIGHAND	0x00000200
 #define FORK_PTRACE	0x00000400
 #define FORK_THREAD	0x00000800
@@ -483,7 +489,7 @@ void	reaper(void);
 void	exit1(struct proc *, int, int);
 void	exit2(struct proc *);
 void	cpu_exit(struct proc *);
-int	fork1(struct proc *, int, int, void *, size_t, void (*)(void *),
+int	fork1(struct proc *, int, int, void *, pid_t *, void (*)(void *),
 	    void *, register_t *, struct proc **);
 int	groupmember(gid_t, struct ucred *);
 
diff --git a/sys/sys/unistd.h b/sys/sys/unistd.h
index 7a5b3ede8af..52b8545c6a6 100644
--- a/sys/sys/unistd.h
+++ b/sys/sys/unistd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: unistd.h,v 1.18 2010/10/28 02:05:59 deraadt Exp $	*/
+/*	$OpenBSD: unistd.h,v 1.19 2011/10/15 23:35:29 guenther Exp $	*/
 /*	$NetBSD: unistd.h,v 1.10 1994/06/29 06:46:06 cgd Exp $	*/
 
 /*
@@ -72,6 +72,13 @@
 #define	L_SET		SEEK_SET
 #define	L_INCR		SEEK_CUR
 #define	L_XTND		SEEK_END
+
+/* the parameters argument passed to the __tfork() syscall */
+struct __tfork {
+	void	*tf_tcb;
+	pid_t	*tf_tid;
+	int	tf_flags;
+};
 #endif
 
 /* configurable pathname variables */