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[src/trunk]: src/sys Eliminate per-hook duplication of common code as suggest...
details: https://anonhg.NetBSD.org/src/rev/6e20fa74bf14
branches: trunk
changeset: 967519:6e20fa74bf14
user: pgoyette <pgoyette%NetBSD.org@localhost>
date: Thu Dec 12 22:55:20 2019 +0000
description:
Eliminate per-hook duplication of common code as suggested by
(and with major contributions from) riastradh@
Welcome to 9.99.23
diffstat:
sys/kern/files.kern | 3 +-
sys/kern/init_main.c | 6 +-
sys/kern/kern_module.c | 14 +--
sys/kern/kern_module_hook.c | 132 ++++++++++++++++++++++++++++
sys/rump/librump/rumpkern/Makefile.rumpkern | 3 +-
sys/sys/module_hook.h | 96 ++++---------------
sys/sys/param.h | 4 +-
7 files changed, 165 insertions(+), 93 deletions(-)
diffs (truncated from 406 to 300 lines):
diff -r bbc28b1f0050 -r 6e20fa74bf14 sys/kern/files.kern
--- a/sys/kern/files.kern Thu Dec 12 20:14:21 2019 +0000
+++ b/sys/kern/files.kern Thu Dec 12 22:55:20 2019 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: files.kern,v 1.38 2019/11/20 19:37:53 pgoyette Exp $
+# $NetBSD: files.kern,v 1.39 2019/12/12 22:55:20 pgoyette Exp $
#
# kernel sources
@@ -54,6 +54,7 @@
file kern/kern_lwp.c kern
file kern/kern_malloc.c kern
file kern/kern_module.c kern
+file kern/kern_module_hook.c kern
file kern/kern_module_vfs.c kern
file kern/kern_mutex.c kern
file kern/kern_mutex_obj.c kern
diff -r bbc28b1f0050 -r 6e20fa74bf14 sys/kern/init_main.c
--- a/sys/kern/init_main.c Thu Dec 12 20:14:21 2019 +0000
+++ b/sys/kern/init_main.c Thu Dec 12 22:55:20 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: init_main.c,v 1.508 2019/12/02 23:22:43 ad Exp $ */
+/* $NetBSD: init_main.c,v 1.509 2019/12/12 22:55:20 pgoyette Exp $ */
/*-
* Copyright (c) 2008, 2009, 2019 The NetBSD Foundation, Inc.
@@ -97,7 +97,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.508 2019/12/02 23:22:43 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.509 2019/12/12 22:55:20 pgoyette Exp $");
#include "opt_ddb.h"
#include "opt_inet.h"
@@ -170,6 +170,7 @@
#include <sys/disk.h>
#include <sys/msgbuf.h>
#include <sys/module.h>
+#include <sys/module_hook.h>
#include <sys/event.h>
#include <sys/lockf.h>
#include <sys/once.h>
@@ -354,6 +355,7 @@
/* Start module system. */
module_init();
+ module_hook_init();
/*
* Initialize the kernel authorization subsystem and start the
diff -r bbc28b1f0050 -r 6e20fa74bf14 sys/kern/kern_module.c
--- a/sys/kern/kern_module.c Thu Dec 12 20:14:21 2019 +0000
+++ b/sys/kern/kern_module.c Thu Dec 12 22:55:20 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_module.c,v 1.140 2019/12/12 16:36:25 pgoyette Exp $ */
+/* $NetBSD: kern_module.c,v 1.141 2019/12/12 22:55:20 pgoyette Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.140 2019/12/12 16:36:25 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.141 2019/12/12 22:55:20 pgoyette Exp $");
#define _MODULE_INTERNAL
@@ -128,12 +128,6 @@
static void module_callback_load(struct module *);
static void module_callback_unload(struct module *);
-/* Locking/synchronization stuff for module hooks */
-
-kmutex_t module_hook_mtx;
-kcondvar_t module_hook_cv;
-pserialize_t module_hook_psz;
-
#define MODULE_CLASS_MATCH(mi, modclass) \
((modclass) == MODULE_CLASS_ANY || (modclass) == (mi)->mi_class)
@@ -451,10 +445,6 @@
module_netbsd = module_newmodule(MODULE_SOURCE_KERNEL);
module_netbsd->mod_refcnt = 1;
module_netbsd->mod_info = &module_netbsd_modinfo;
-
- mutex_init(&module_hook_mtx, MUTEX_DEFAULT, IPL_NONE);
- cv_init(&module_hook_cv, "mod_hook");
- module_hook_psz = pserialize_create();
}
/*
diff -r bbc28b1f0050 -r 6e20fa74bf14 sys/kern/kern_module_hook.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/kern/kern_module_hook.c Thu Dec 12 22:55:20 2019 +0000
@@ -0,0 +1,132 @@
+/* $NetBSD: kern_module_hook.c,v 1.1 2019/12/12 22:55:20 pgoyette Exp $ */
+
+/*-
+ * Copyright (c) 2019 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Kernel module support.
+ */
+
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: kern_module_hook.c,v 1.1 2019/12/12 22:55:20 pgoyette Exp $");
+
+#include <sys/param.h>
+#include <sys/module_hook.h>
+#include <sys/mutex.h>
+#include <sys/condvar.h>
+#include <sys/pserialize.h>
+
+#include <uvm/uvm_extern.h>
+
+/* Locking/synchronization stuff for module hooks */
+
+static struct {
+ kmutex_t mtx;
+ kcondvar_t cv;
+ pserialize_t psz;
+} module_hook __cacheline_aligned;
+
+/*
+ * We use pserialize_perform() to issue a memory barrier on the current
+ * CPU and on all other CPUs so that all prior memory operations on the
+ * current CPU globally happen before all subsequent memory operations
+ * on the current CPU, as perceived by any other CPU.
+ *
+ * pserialize_perform() might be rather heavy-weight here, but it only
+ * happens during module loading, and it allows MODULE_HOOK_CALL() to
+ * work without any other memory barriers.
+ */
+
+void
+module_hook_set(bool *hooked, struct localcount *lc)
+{
+
+ KASSERT(kernconfig_is_held());
+ KASSERT(!*hooked);
+
+ localcount_init(lc);
+
+ /* Wait until setup has been witnessed by all CPUs. */
+ pserialize_perform(module_hook.psz);
+
+ /* Let others use it */
+ atomic_store_relaxed(hooked, true);
+}
+
+void
+module_hook_unset(bool *hooked, struct localcount *lc)
+{
+
+ KASSERT(kernconfig_is_held());
+ KASSERT(*hooked);
+
+ /* Get exclusive with pserialize and localcount. */
+ mutex_enter(&module_hook.mtx);
+
+ /* Prevent new calls to module_hook_tryenter(). */
+ atomic_store_relaxed(hooked, false);
+
+ /* Wait for existing calls to module_hook_tryenter(). */
+ pserialize_perform(module_hook.psz);
+
+ /* Wait for module_hook_exit. */
+ localcount_drain(lc, &module_hook.cv, &module_hook.mtx);
+
+ /* All done! */
+ mutex_exit(&module_hook.mtx);
+ localcount_fini(lc);
+}
+
+bool
+module_hook_tryenter(bool *hooked, struct localcount *lc)
+{
+ bool call_hook;
+ int s;
+
+ s = pserialize_read_enter();
+ call_hook = atomic_load_relaxed(hooked);
+ if (call_hook)
+ localcount_acquire(lc);
+ pserialize_read_exit(s);
+
+ return call_hook;
+}
+
+void
+module_hook_exit(struct localcount *lc)
+{
+
+ localcount_release(lc, &module_hook.cv, &module_hook.mtx);
+}
+
+void
+module_hook_init(void)
+{
+
+ mutex_init(&module_hook.mtx, MUTEX_DEFAULT, IPL_NONE);
+ cv_init(&module_hook.cv, "mod_hook");
+ module_hook.psz = pserialize_create();
+}
diff -r bbc28b1f0050 -r 6e20fa74bf14 sys/rump/librump/rumpkern/Makefile.rumpkern
--- a/sys/rump/librump/rumpkern/Makefile.rumpkern Thu Dec 12 20:14:21 2019 +0000
+++ b/sys/rump/librump/rumpkern/Makefile.rumpkern Thu Dec 12 22:55:20 2019 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile.rumpkern,v 1.177 2019/10/13 07:28:14 mrg Exp $
+# $NetBSD: Makefile.rumpkern,v 1.178 2019/12/12 22:55:20 pgoyette Exp $
#
IOCONFDIR:= ${.PARSEDIR}
@@ -75,6 +75,7 @@
kern_ksyms.c \
kern_malloc.c \
kern_module.c \
+ kern_module_hook.c \
kern_mutex_obj.c \
kern_ntptime.c \
kern_proc.c \
diff -r bbc28b1f0050 -r 6e20fa74bf14 sys/sys/module_hook.h
--- a/sys/sys/module_hook.h Thu Dec 12 20:14:21 2019 +0000
+++ b/sys/sys/module_hook.h Thu Dec 12 22:55:20 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: module_hook.h,v 1.5 2019/12/12 02:15:43 pgoyette Exp $ */
+/* $NetBSD: module_hook.h,v 1.6 2019/12/12 22:55:20 pgoyette Exp $ */
/*-
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -33,11 +33,14 @@
#define _SYS_MODULE_HOOK_H
#include <sys/param.h> /* for COHERENCY_UNIT, for __cacheline_aligned */
-#include <sys/mutex.h>
#include <sys/localcount.h>
-#include <sys/condvar.h>
-#include <sys/pserialize.h>
-#include <sys/atomic.h>
+#include <sys/stdbool.h>
+
+void module_hook_init(void);
+void module_hook_set(bool *, struct localcount *);
+void module_hook_unset(bool *, struct localcount *);
+bool module_hook_tryenter(bool *, struct localcount *);
+void module_hook_exit(struct localcount *);
/*
* Macros for creating MP-safe vectored function calls, where
@@ -48,14 +51,10 @@
#define MODULE_HOOK(hook, type, args) \
extern struct hook ## _t { \
struct localcount lc; \
- bool hooked; \
type (*f)args; \
+ bool hooked; \
} hook __cacheline_aligned;
-extern kmutex_t module_hook_mtx;
-extern kcondvar_t module_hook_cv;
-extern pserialize_t module_hook_psz;
-
/*
* We use pserialize_perform() to issue a memory barrier on the current
* CPU and on all other CPUs so that all prior memory operations on the
@@ -69,85 +68,32 @@
#define MODULE_HOOK_SET(hook, func) \
do { \
- \
- KASSERT(kernconfig_is_held()); \
- KASSERT(!hook.hooked); \
- \
- localcount_init(&hook.lc); \
- hook.f = func; \
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