thread stack handling changes. Add guard zones and allow stack

size (and guard zone size) to be set using pthread_attr.   Guard
zones are specified in bytes, but implemented in terms of a
page size.

OK Otto@

5 files changed, 156 insertions, 43 deletions

diff --git a/lib/librthread/Makefile b/lib/librthread/Makefile
index 1f488ace167..24a0fa53fdc 100644
--- a/lib/librthread/Makefile
+++ b/lib/librthread/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.6 2005/12/31 21:40:43 marc Exp $
+#	$OpenBSD: Makefile,v 1.7 2006/01/01 19:32:30 marc Exp $
 
 LIB=rthread
 WANTLINT=
@@ -7,7 +7,7 @@ CFLAGS+=-Wall -g -Werror -Wshadow
 
 .PATH: ${.CURDIR}/arch/${MACHINE_ARCH}
 SRCS= rthread.c rthread_attr.c rthread_sched.c rthread_sync.c rthread_tls.c \
-	rthread_sig.c rthread_np.c rthread_debug.c
+	rthread_sig.c rthread_np.c rthread_debug.c rthread_stack.c
 
 OBJS+= _atomic_lock.o rfork_thread.o
 
diff --git a/lib/librthread/rthread.c b/lib/librthread/rthread.c
index 71bff294202..b4d07b73903 100644
--- a/lib/librthread/rthread.c
+++ b/lib/librthread/rthread.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rthread.c,v 1.25 2005/12/31 08:51:20 otto Exp $ */
+/*	$OpenBSD: rthread.c,v 1.26 2006/01/01 19:32:30 marc Exp $ */
 /*
  * Copyright (c) 2004,2005 Ted Unangst <tedu@openbsd.org>
  * All Rights Reserved.
@@ -111,40 +111,6 @@ _rthread_init(void)
 	return (0);
 }
 
-static struct stack *
-_rthread_alloc_stack(size_t len, void *base)
-{
-	struct stack *stack;
-
-	stack = malloc(sizeof(*stack));
-	if (!stack)
-		return (NULL);
-	if (base) {
-		stack->base = base;
-	} else {
-		stack->base = mmap(NULL, len, PROT_READ | PROT_WRITE,
-		    MAP_ANON, -1, 0);
-		if (stack->base == MAP_FAILED) {
-			free(stack);
-			return (NULL);
-		}
-	}
-#ifdef MACHINE_STACK_GROWS_UP
-	stack->sp = (void *)(((size_t)stack->base + 64) & ~63);
-#else
-	stack->sp = (void *)(((size_t)stack->base + len - 16) & ~15);
-#endif
-	stack->len = len;
-	return (stack);
-}
-
-static void
-_rthread_free_stack(struct stack *stack)
-{
-	munmap(stack->base, stack->len);
-	free(stack);
-}
-
 /*
  * real pthread functions
  */
@@ -238,10 +204,15 @@ pthread_create(pthread_t *threadp, const pthread_attr_t *attr,
 	thread->arg = arg;
 	if (attr)
 		thread->attr = *(*attr);
+	else {
+		thread->attr.stack_size = RTHREAD_STACK_SIZE_DEF;
+		thread->attr.guard_size = sysconf(_SC_PAGESIZE);
+		thread->attr.stack_size -= thread->attr.guard_size;
+	}
 
 	_spinlock(&_thread_lock);
 
-	thread->stack = _rthread_alloc_stack(64 * 1024, NULL);
+	thread->stack = _rthread_alloc_stack(thread);
 	if (!thread->stack) {
 		rc = errno;
 		goto fail1;
diff --git a/lib/librthread/rthread.h b/lib/librthread/rthread.h
index 792b9259a19..9a312ef64bc 100644
--- a/lib/librthread/rthread.h
+++ b/lib/librthread/rthread.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rthread.h,v 1.14 2005/12/31 21:40:43 marc Exp $ */
+/*	$OpenBSD: rthread.h,v 1.15 2006/01/01 19:32:30 marc Exp $ */
 /*
  * Copyright (c) 2004,2005 Ted Unangst <tedu@openbsd.org>
  * All Rights Reserved.
@@ -27,9 +27,13 @@
 
 #include <sys/queue.h>
 
+#define RTHREAD_STACK_SIZE_DEF (64 * 1024)
+
 struct stack {
 	void *sp;
 	void *base;
+	void *guard;
+	size_t guardsize;
 	size_t len;
 };
 
@@ -73,6 +77,7 @@ struct pthread_rwlockattr {
 struct pthread_attr {
 	void *stack_addr;
 	size_t stack_size;
+	size_t guard_size;
 	int detach_state;
 	int contention_scope;
 	int sched_policy;
@@ -134,10 +139,14 @@ int	_sem_post(sem_t);
 int	_sem_wakeup(sem_t);
 int	_sem_wakeall(sem_t);
 
+struct stack *_rthread_alloc_stack(pthread_t);
+void	_rthread_free_stack(struct stack *);
 void	_rthread_tls_destructors(pthread_t);
 void	_rthread_debug(int, const char *, ...)
 		__attribute__((__format__ (printf, 2, 3)));
 
+void	_thread_dump_info(void);
+
 int	_atomic_lock(register volatile _spinlock_lock_t *);
 
 /* syscalls */
diff --git a/lib/librthread/rthread_attr.c b/lib/librthread/rthread_attr.c
index 93a18346079..741c4641aff 100644
--- a/lib/librthread/rthread_attr.c
+++ b/lib/librthread/rthread_attr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rthread_attr.c,v 1.4 2005/12/31 08:51:20 otto Exp $ */
+/*	$OpenBSD: rthread_attr.c,v 1.5 2006/01/01 19:32:30 marc Exp $ */
 /*
  * Copyright (c) 2004,2005 Ted Unangst <tedu@openbsd.org>
  * All Rights Reserved.
@@ -36,6 +36,17 @@
 
 #include "rthread.h"
 
+/*
+ * Note: stack_size + guard_size == total stack used
+ *
+ * pthread_attr_init MUST be called before any other attribute function
+ * for proper operation.
+ *
+ * Every call to pthread_attr_init MUST be matched with a call to
+ * pthread_attr_destroy to avoid leaking memory.   This is an implementation
+ * requirement, not a POSIX requirement.
+ */
+
 int
 pthread_attr_init(pthread_attr_t *attrp)
 {
@@ -45,6 +56,9 @@ pthread_attr_init(pthread_attr_t *attrp)
 	if (!attr)
 		return (errno);
 	memset(attr, 0, sizeof(*attr));
+	attr->stack_size = RTHREAD_STACK_SIZE_DEF;
+	attr->guard_size = sysconf(_SC_PAGESIZE);
+	attr->stack_size -= attr->guard_size;
 	*attrp = attr;
 
 	return (0);
@@ -60,6 +74,26 @@ pthread_attr_destroy(pthread_attr_t *attrp)
 }
 
 int
+pthread_attr_getguardsize(const pthread_attr_t *attrp, size_t *guardsize)
+{
+	*guardsize = (*attrp)->guard_size;
+
+	return (0);
+}
+
+int
+pthread_attr_setguardsize(pthread_attr_t *attrp, size_t guardsize)
+{
+	if ((*attrp)->guard_size != guardsize) {
+		(*attrp)->stack_size += (*attrp)->guard_size;
+		(*attrp)->guard_size = guardsize;
+		(*attrp)->stack_size -= (*attrp)->guard_size;
+	}
+
+	return 0;
+}
+
+int
 pthread_attr_getdetachstate(const pthread_attr_t *attrp, int *detachstate)
 {
 	*detachstate = (*attrp)->detach_state;
@@ -70,6 +104,7 @@ pthread_attr_getdetachstate(const pthread_attr_t *attrp, int *detachstate)
 int
 pthread_attr_setdetachstate(pthread_attr_t *attrp, int detachstate)
 {
+	/* XXX detachstate should be validated here */
 	(*attrp)->detach_state = detachstate;
 
 	return (0);
@@ -80,7 +115,7 @@ pthread_attr_getstack(const pthread_attr_t *attrp, void **stackaddr,
     size_t *stacksize)
 {
 	*stackaddr = (*attrp)->stack_addr;
-	*stacksize = (*attrp)->stack_size;
+	*stacksize = (*attrp)->stack_size + (*attrp)->guard_size;
 
 	return (0);
 }
@@ -90,6 +125,7 @@ pthread_attr_setstack(pthread_attr_t *attrp, void *stackaddr, size_t stacksize)
 {
 	(*attrp)->stack_addr = stackaddr;
 	(*attrp)->stack_size = stacksize;
+	(*attrp)->stack_size -= (*attrp)->guard_size;
 
 	return (0);
 }
@@ -97,8 +133,8 @@ pthread_attr_setstack(pthread_attr_t *attrp, void *stackaddr, size_t stacksize)
 int
 pthread_attr_getstacksize(const pthread_attr_t *attrp, size_t *stacksize)
 {
-	*stacksize = (*attrp)->stack_size;
-
+	*stacksize = (*attrp)->stack_size + (*attrp)->guard_size;
+	
 	return (0);
 }
 
@@ -106,6 +142,10 @@ int
 pthread_attr_setstacksize(pthread_attr_t *attrp, size_t stacksize)
 {
 	(*attrp)->stack_size = stacksize;
+	if ((*attrp)->stack_size > (*attrp)->guard_size)
+		(*attrp)->stack_size -= (*attrp)->guard_size;
+	else
+		(*attrp)->stack_size = 0;
 
 	return (0);
 }
@@ -137,6 +177,7 @@ pthread_attr_getscope(const pthread_attr_t *attrp, int *contentionscope)
 int
 pthread_attr_setscope(pthread_attr_t *attrp, int contentionscope)
 {
+	/* XXX contentionscope should be validated here */
 	(*attrp)->contention_scope = contentionscope;
 
 	return (0);
diff --git a/lib/librthread/rthread_stack.c b/lib/librthread/rthread_stack.c
new file mode 100644
index 00000000000..05a1f6158ea
--- /dev/null
+++ b/lib/librthread/rthread_stack.c
@@ -0,0 +1,92 @@
+/* $OpenBSD: rthread_stack.c,v 1.1 2006/01/01 19:32:30 marc Exp $ */
+/* $snafu: rthread_stack.c,v 1.12 2005/01/11 02:45:28 marc Exp $ */
+
+/* PUBLIC DOMAIN: No Rights Reserved. Marco S Hyman <marc@snafu.org> */
+
+#include <sys/types.h>
+#include <sys/mman.h>
+
+#include <machine/param.h>
+#include <machine/spinlock.h>
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "rthread.h"
+
+struct stack *
+_rthread_alloc_stack(pthread_t thread)
+{
+	struct stack *stack;
+	caddr_t base;
+	caddr_t guard;
+	caddr_t start = NULL;
+	size_t pgsz;
+	size_t size;
+
+	/* guard pages are forced to a multiple of the page size */
+	pgsz = sysconf(_SC_PAGESIZE);
+	if (pgsz == (size_t)-1)
+		return NULL;
+
+	/* figure out the actual requested size, including guard size */
+	size = thread->attr.stack_size + thread->attr.guard_size;
+	size += pgsz - 1;
+	size &= ~(pgsz - 1);
+
+	/*
+	 * Allocate some stack space unless and address was provided.
+	 * A provided address is ASSUMED to be correct with respect to
+	 * alignment constraints.
+	 */
+	if (size > thread->attr.guard_size) {
+		if (thread->attr.stack_addr)
+			base = thread->attr.stack_addr;
+		else {
+			base = mmap(NULL, size, PROT_READ | PROT_WRITE,
+				    MAP_ANON, -1, 0);
+			if (base == MAP_FAILED)
+				return (NULL);
+		}
+		/* memory protect the guard region */
+
+#ifdef MACHINE_STACK_GROWS_UP
+		guard = base + size - thread->attr.guard_size;
+		start = base;
+#else
+		guard = base;
+		start = base + size;
+#endif
+		if (mprotect(guard, thread->attr.guard_size, PROT_NONE) == -1) {
+			munmap(base, size);
+			return (NULL);
+		}
+
+		/* wrap up the info in a struct stack and return it */
+		stack = malloc(sizeof(*stack));
+		if (!stack) {
+			mprotect(guard, thread->attr.guard_size,
+				 PROT_EXEC | PROT_READ | PROT_WRITE);
+			munmap(base, size);
+			return (NULL);
+		}
+		stack->sp = start;
+		stack->base = base;
+		stack->guard = guard;
+		stack->guardsize = thread->attr.guard_size;
+		stack->len = size;
+		return (stack);
+	}
+	return (NULL);
+}
+
+void
+_rthread_free_stack(struct stack *stack)
+{
+	mprotect(stack->guard, stack->guardsize,
+		 PROT_EXEC | PROT_READ | PROT_WRITE);
+	munmap(stack->base, stack->len);
+	free(stack);
+}
+