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Date:      Mon, 24 Aug 2020 12:59:55 +0000 (UTC)
From:      Emmanuel Vadot <manu@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org
Subject:   svn commit: r364671 - in stable/12/sys: compat/linuxkpi/common/include/linux compat/linuxkpi/common/src conf libkern sys
Message-ID:  <202008241259.07OCxt1i042570@repo.freebsd.org>

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Author: manu
Date: Mon Aug 24 12:59:55 2020
New Revision: 364671
URL: https://svnweb.freebsd.org/changeset/base/364671

Log:
  MFC r361247, r361343, r361418-r361419, r361422, r361449
  
  r361247:
  linuxkpi: Add irq_work.h
  
  Since handlers are call in a thread context we can simply use a workqueue
  to emulate those functions.
  The DRM code was patched to do that already, having it in linuxkpi allows us
  to not patch the upstream code.
  
  Sponsored-by: The FreeBSD Foundation
  Reviewed by:	hselasky
  Differential Revision:	https://reviews.freebsd.org/D24859
  
  r361343:
  linuxkpi: Add rcu_work functions
  
  The rcu_work function helps to queue some work after waiting for a grace
  period.
  This is needed by DRM drivers.
  
  Sponsored-by: The FreeBSD Foundation
  Reviewed by:	hselasky
  Differential Revision:	https://reviews.freebsd.org/D24942
  
  r361418:
  libkern: Add arc4random_uniform
  
  This variant get a random number up to the limit passed as the argument.
  This is simply a copy of the libc version.
  
  Sponsored-by: The FreeBSD Foundation
  Reviewed by:	cem, hselasky (previous version)
  Differential Revision:	https://reviews.freebsd.org/D24962
  
  r361419:
  linuxkpi: Add prandom_u32_max
  
  This is just a wrapper around arc4random_uniform
  Needed by DRM v5.3
  
  Sponsored-by: The FreeBSD Foundation
  Reviewed by:	cem, hselasky
  Differential Revision:	https://reviews.freebsd.org/D24961
  
  r361422:
  bbr: Use arc4random_uniform from libkern.
  
  This unbreak LINT build
  
  Reported by:	jenkins, melifaro
  
  r361449:
  linuxkpi: Add __same_type and __must_be_array macros
  
  The same_type macro simply wraps around builtin_types_compatible_p which
  exist for both GCC and CLANG, which returns 1 if both types are the same.
  The __must_be_array macros returns 1 if the argument is an array.
  
  This is needed for DRM v5.3
  
  Sponsored-by: The FreeBSD Foundation
  Reviewed by:	hselasky
  Differential Revision:	https://reviews.freebsd.org/D24953

Added:
  stable/12/sys/compat/linuxkpi/common/include/linux/irq_work.h
     - copied unchanged from r361247, head/sys/compat/linuxkpi/common/include/linux/irq_work.h
  stable/12/sys/libkern/arc4random_uniform.c
     - copied unchanged from r361419, head/sys/libkern/arc4random_uniform.c
Modified:
  stable/12/sys/compat/linuxkpi/common/include/linux/compiler.h
  stable/12/sys/compat/linuxkpi/common/include/linux/random.h
  stable/12/sys/compat/linuxkpi/common/include/linux/workqueue.h
  stable/12/sys/compat/linuxkpi/common/src/linux_work.c
  stable/12/sys/conf/files
  stable/12/sys/sys/libkern.h
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/compat/linuxkpi/common/include/linux/compiler.h
==============================================================================
--- stable/12/sys/compat/linuxkpi/common/include/linux/compiler.h	Mon Aug 24 12:59:15 2020	(r364670)
+++ stable/12/sys/compat/linuxkpi/common/include/linux/compiler.h	Mon Aug 24 12:59:55 2020	(r364671)
@@ -111,4 +111,7 @@
 
 #define	_AT(T,X)	((T)(X))
 
+#define	__same_type(a, b)	__builtin_types_compatible_p(typeof(a), typeof(b))
+#define	__must_be_array(a)	__same_type(a, &(a)[0])
+
 #endif	/* _LINUX_COMPILER_H_ */

Copied: stable/12/sys/compat/linuxkpi/common/include/linux/irq_work.h (from r361247, head/sys/compat/linuxkpi/common/include/linux/irq_work.h)
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ stable/12/sys/compat/linuxkpi/common/include/linux/irq_work.h	Mon Aug 24 12:59:55 2020	(r364671, copy of r361247, head/sys/compat/linuxkpi/common/include/linux/irq_work.h)
@@ -0,0 +1,52 @@
+/*-
+ * Copyright (c) 2020 The FreeBSD Foundation
+ *
+ * This software was developed by Emmanuel Vadot under sponsorship
+ * from the FreeBSD Foundation.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef __LINUX_IRQ_WORK_H__
+#define	__LINUX_IRQ_WORK_H__
+
+#include <linux/workqueue.h>
+
+struct irq_work {
+	struct work_struct work;
+};
+
+static inline void
+init_irq_work(struct irq_work *irqw, void (*func)(struct irq_work *))
+{
+	INIT_WORK(&irqw->work, (work_func_t)func);
+}
+
+static inline void
+irq_work_queue(struct irq_work *irqw)
+{
+	schedule_work(&irqw->work);
+}
+
+#endif /* __LINUX_IRQ_WORK_H__ */

Modified: stable/12/sys/compat/linuxkpi/common/include/linux/random.h
==============================================================================
--- stable/12/sys/compat/linuxkpi/common/include/linux/random.h	Mon Aug 24 12:59:15 2020	(r364670)
+++ stable/12/sys/compat/linuxkpi/common/include/linux/random.h	Mon Aug 24 12:59:55 2020	(r364671)
@@ -63,4 +63,10 @@ get_random_long(void)
 	return (val);
 }
 
+static inline u32
+prandom_u32_max(u32 max)
+{
+	return (arc4random_uniform(max));
+}
+
 #endif /* _LINUX_RANDOM_H_ */

Modified: stable/12/sys/compat/linuxkpi/common/include/linux/workqueue.h
==============================================================================
--- stable/12/sys/compat/linuxkpi/common/include/linux/workqueue.h	Mon Aug 24 12:59:15 2020	(r364670)
+++ stable/12/sys/compat/linuxkpi/common/include/linux/workqueue.h	Mon Aug 24 12:59:55 2020	(r364671)
@@ -72,6 +72,13 @@ struct work_struct {
 	atomic_t state;
 };
 
+struct rcu_work {
+	struct work_struct work;
+	struct rcu_head rcu;
+
+	struct workqueue_struct *wq;
+};
+
 #define	DECLARE_WORK(name, fn)						\
 	struct work_struct name;					\
 	static void name##_init(void *arg)				\
@@ -111,6 +118,9 @@ do {									\
 	TASK_INIT(&(work)->work_task, 0, linux_work_fn, (work));	\
 } while (0)
 
+#define INIT_RCU_WORK(_work, _fn) \
+	INIT_WORK(&(_work)->work, (_fn))
+
 #define	INIT_WORK_ONSTACK(work, fn) \
 	INIT_WORK(work, fn)
 
@@ -191,6 +201,12 @@ do {									\
 #define	flush_work(work) \
 	linux_flush_work(work)
 
+#define	queue_rcu_work(wq, rwork) \
+	linux_queue_rcu_work(wq, rwork)
+
+#define	flush_rcu_work(rwork) \
+	linux_flush_rcu_work(rwork)
+
 #define	flush_delayed_work(dwork) \
 	linux_flush_delayed_work(dwork)
 
@@ -236,5 +252,7 @@ extern bool linux_flush_delayed_work(struct delayed_wo
 extern bool linux_work_pending(struct work_struct *);
 extern bool linux_work_busy(struct work_struct *);
 extern struct work_struct *linux_current_work(void);
+extern bool linux_queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
+extern bool linux_flush_rcu_work(struct rcu_work *rwork);
 
 #endif					/* _LINUX_WORKQUEUE_H_ */

Modified: stable/12/sys/compat/linuxkpi/common/src/linux_work.c
==============================================================================
--- stable/12/sys/compat/linuxkpi/common/src/linux_work.c	Mon Aug 24 12:59:15 2020	(r364670)
+++ stable/12/sys/compat/linuxkpi/common/src/linux_work.c	Mon Aug 24 12:59:55 2020	(r364671)
@@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$");
 #include <linux/wait.h>
 #include <linux/compat.h>
 #include <linux/spinlock.h>
+#include <linux/rcupdate.h>
 
 #include <sys/kernel.h>
 
@@ -153,6 +154,53 @@ linux_queue_work_on(int cpu __unused, struct workqueue
 	default:
 		return (false);		/* already on a queue */
 	}
+}
+
+/*
+ * Callback func for linux_queue_rcu_work
+ */
+static void
+rcu_work_func(struct rcu_head *rcu)
+{
+	struct rcu_work *rwork;
+
+	rwork = container_of(rcu, struct rcu_work, rcu);
+	linux_queue_work_on(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
+}
+
+/*
+ * This function queue a work after a grace period
+ * If the work was already pending it returns false,
+ * if not it calls call_rcu and returns true.
+ */
+bool
+linux_queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
+{
+
+	if (!linux_work_pending(&rwork->work)) {
+		rwork->wq = wq;
+		linux_call_rcu(RCU_TYPE_REGULAR, &rwork->rcu, rcu_work_func);
+		return (true);
+	}
+	return (false);
+}
+
+/*
+ * This function waits for the last execution of a work and then
+ * flush the work.
+ * It returns true if the work was pending and we waited, it returns
+ * false otherwise.
+ */
+bool
+linux_flush_rcu_work(struct rcu_work *rwork)
+{
+
+	if (linux_work_pending(&rwork->work)) {
+		linux_rcu_barrier(RCU_TYPE_REGULAR);
+		linux_flush_work(&rwork->work);
+		return (true);
+	}
+	return (linux_flush_work(&rwork->work));
 }
 
 /*

Modified: stable/12/sys/conf/files
==============================================================================
--- stable/12/sys/conf/files	Mon Aug 24 12:59:15 2020	(r364670)
+++ stable/12/sys/conf/files	Mon Aug 24 12:59:55 2020	(r364671)
@@ -4071,6 +4071,7 @@ kgssapi/gsstest.c		optional kgssapi_debug
 # the file should be moved to conf/files.<arch> from here.
 #
 libkern/arc4random.c		standard
+libkern/arc4random_uniform.c	standard
 crypto/chacha20/chacha.c	standard
 libkern/asprintf.c		standard
 libkern/bcd.c			standard

Copied: stable/12/sys/libkern/arc4random_uniform.c (from r361419, head/sys/libkern/arc4random_uniform.c)
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ stable/12/sys/libkern/arc4random_uniform.c	Mon Aug 24 12:59:55 2020	(r364671, copy of r361419, head/sys/libkern/arc4random_uniform.c)
@@ -0,0 +1,58 @@
+/*	$OpenBSD: arc4random_uniform.c,v 1.3 2019/01/20 02:59:07 bcook Exp $	*/
+
+/*
+ * Copyright (c) 2008, Damien Miller <djm@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.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/types.h>
+#include <sys/libkern.h>
+
+/*
+ * Calculate a uniformly distributed random number less than upper_bound
+ * avoiding "modulo bias".
+ *
+ * Uniformity is achieved by generating new random numbers until the one
+ * returned is outside the range [0, 2**32 % upper_bound).  This
+ * guarantees the selected random number will be inside
+ * [2**32 % upper_bound, 2**32) which maps back to [0, upper_bound)
+ * after reduction modulo upper_bound.
+ */
+uint32_t
+arc4random_uniform(uint32_t upper_bound)
+{
+	uint32_t r, min;
+
+	if (upper_bound < 2)
+		return 0;
+
+	/* 2**32 % x == (2**32 - x) % x */
+	min = -upper_bound % upper_bound;
+
+	/*
+	 * This could theoretically loop forever but each retry has
+	 * p > 0.5 (worst case, usually far better) of selecting a
+	 * number inside the range we need, so it should rarely need
+	 * to re-roll.
+	 */
+	for (;;) {
+		r = arc4random();
+		if (r >= min)
+			break;
+	}
+
+	return r % upper_bound;
+}

Modified: stable/12/sys/sys/libkern.h
==============================================================================
--- stable/12/sys/sys/libkern.h	Mon Aug 24 12:59:15 2020	(r364670)
+++ stable/12/sys/sys/libkern.h	Mon Aug 24 12:59:55 2020	(r364671)
@@ -127,6 +127,7 @@ extern int arc4rand_iniseed_state;
 struct malloc_type;
 uint32_t arc4random(void);
 void	 arc4random_buf(void *, size_t);
+uint32_t arc4random_uniform(uint32_t);
 void	 arc4rand(void *, u_int, int);
 int	 timingsafe_bcmp(const void *, const void *, size_t);
 void	*bsearch(const void *, const void *, size_t,



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