[PATCH rtems-libbsd 3/7] sys/kern: Add lockmgr support
Sebastian Huber
sebastian.huber at embedded-brains.de
Wed Jul 28 06:23:10 UTC 2021
On 27/07/2021 10:58, chrisj at rtems.org wrote:
> From: Chris Johns <chrisj at rtems.org>
>
> - See `man lockmgr`
>
> - Implement the lock_object and move the RTEMS mutex to that object
>
> - Add debug support to track the locks with gdb
>
> Update #4475
> ---
> freebsd/sys/sys/_lock.h | 10 +-
> freebsd/sys/sys/_lockmgr.h | 6 +
> freebsd/sys/sys/_mutex.h | 5 -
> freebsd/sys/sys/_rwlock.h | 5 -
> freebsd/sys/sys/_sx.h | 5 -
> rtemsbsd/include/machine/_kernel_lock.h | 2 +-
> rtemsbsd/include/machine/rtems-bsd-mutex.h | 8 +-
> .../include/machine/rtems-bsd-muteximpl.h | 87 ++-
> rtemsbsd/include/machine/rtems-bsd-thread.h | 1 +
> rtemsbsd/rtems/rtems-kernel-epoch.c | 2 +-
> rtemsbsd/rtems/rtems-kernel-jail.c | 10 +-
> rtemsbsd/rtems/rtems-kernel-lockmgr.c | 578 ++++++++++++++++++
> rtemsbsd/rtems/rtems-kernel-mutex.c | 21 +-
> rtemsbsd/rtems/rtems-kernel-muteximpl.c | 5 +-
> rtemsbsd/rtems/rtems-kernel-rwlock.c | 28 +-
> rtemsbsd/rtems/rtems-kernel-sx.c | 34 +-
> 16 files changed, 724 insertions(+), 83 deletions(-)
> create mode 100644 rtemsbsd/rtems/rtems-kernel-lockmgr.c
>
> diff --git a/freebsd/sys/sys/_lock.h b/freebsd/sys/sys/_lock.h
> index ae10254c..9e3388d5 100644
> --- a/freebsd/sys/sys/_lock.h
> +++ b/freebsd/sys/sys/_lock.h
> @@ -32,15 +32,19 @@
>
> #ifndef _SYS__LOCK_H_
> #define _SYS__LOCK_H_
> +#ifdef __rtems__
> +#include <machine/rtems-bsd-mutex.h>
> +#endif /* __rtems__ */
>
> struct lock_object {
> -#ifndef __rtems__
> const char *lo_name; /* Individual lock name. */
> u_int lo_flags;
> u_int lo_data; /* General class specific data. */
> +#ifndef __rtems__
> struct witness *lo_witness; /* Data for witness. */
> -#else /* __rtems__ */
> - unsigned int lo_flags;
> +#endif /* __rtems__ */
> +#ifdef __rtems__
> + rtems_bsd_mutex lo_mtx;
> #endif /* __rtems__ */
> };
This change increases the size by 40% from 20 bytes to 28 bytes. Why do
we need the lo_name? The thread queues have already a name. For what do
we need lo_data?
[...]
> diff --git a/rtemsbsd/include/machine/rtems-bsd-muteximpl.h b/rtemsbsd/include/machine/rtems-bsd-muteximpl.h
> index b362e524..2e180b97 100644
> --- a/rtemsbsd/include/machine/rtems-bsd-muteximpl.h
> +++ b/rtemsbsd/include/machine/rtems-bsd-muteximpl.h
> @@ -50,6 +50,8 @@
>
> #include <inttypes.h>
>
> +#include <rtems/thread.h>
> +#include <rtems/score/thread.h>
> #include <rtems/score/threadimpl.h>
> #include <rtems/score/threadqimpl.h>
>
> @@ -60,17 +62,48 @@ extern "C" {
> #define RTEMS_BSD_MUTEX_TQ_OPERATIONS \
> &_Thread_queue_Operations_priority_inherit
>
> +#if RTEMS_DEBUG
> +/*
> + * Resource tracking. In GDB you can:
> + *
> + * define mutex-owned
> + * set $m = $arg0
> + * set $c = 0
> + * while $m != 0
> + * set $c = $c + 1
> + * if $m->queue.Queue.owner != 0
> + * printf "%08x %-40s\n", $m->queue.Queue.owner, $m->queue.Queue.name
> + * end
> + * set $m = $m->mutex_list.tqe_next
> + * end
> + * printf "Total: %d\n", $c
> + * end
> + *
> + * (gdb) mutex-owned _bsd_bsd_mutexlist->tqh_first
> + */
> +extern TAILQ_HEAD(bsd_mutex_list, rtems_bsd_mutex) bsd_mutexlist;
> +extern rtems_mutex bsd_mutexlist_lock;
> +#endif /* RTEMS_DEBUG */
Global symbols should be prefixed with rtems_bsd or _bsd, but not bsd.
[...]
> diff --git a/rtemsbsd/rtems/rtems-kernel-lockmgr.c b/rtemsbsd/rtems/rtems-kernel-lockmgr.c
> new file mode 100644
> index 00000000..36e7a82f
> --- /dev/null
> +++ b/rtemsbsd/rtems/rtems-kernel-lockmgr.c
> @@ -0,0 +1,578 @@
> +/**
> + * @file
> + *
> + * @ingroup rtems_bsd_rtems
> + *
> + * @brief TODO.
> + */
> +
> +/*
> + * Copyright (c) 2020 Chris Johns. 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 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.
> + */
> +
> +#include <machine/rtems-bsd-kernel-space.h>
> +#include <machine/rtems-bsd-muteximpl.h>
> +#include <machine/rtems-bsd-thread.h>
> +
> +#include <sys/param.h>
> +#include <sys/types.h>
> +#include <sys/systm.h>
> +#include <sys/lock.h>
> +#include <sys/lockmgr.h>
> +#include <sys/mutex.h>
> +#include <sys/proc.h>
> +#include <sys/conf.h>
> +
> +#ifdef DEBUG_LOCKS
> +#define STACK_PRINT(lk) printf("caller: %p\n", (lk)->lk_stack)
> +#define STACK_SAVE(lk) (lk)->lk_stack = __builtin_return_address(0)
> +#define STACK_ZERO(lk) (lk)->lk_stack = NULL
> +#else
> +#define STACK_PRINT(lk)
> +#define STACK_SAVE(lk)
> +#define STACK_ZERO(lk)
> +#endif
> +
> +static void assert_lockmgr(const struct lock_object *lock, int how);
> +static void lock_lockmgr(struct lock_object *lock, uintptr_t how);
> +static uintptr_t unlock_lockmgr(struct lock_object *lock);
> +
> +#define lockmgr_xlocked(lk) \
> + rtems_bsd_mutex_owned(RTEMS_DECONST(struct lock_object*, &lk->lock_object))
> +#define lockmgr_disowned(lk) \
> + !rtems_bsd_mutex_owned(RTEMS_DECONST(struct lock_object*, &lk->lock_object))
> +
> +struct lock_class lock_class_lockmgr = {
> + .lc_name = "lockmgr",
> + .lc_flags = LC_RECURSABLE | LC_SLEEPABLE | LC_SLEEPLOCK | LC_UPGRADABLE,
> + .lc_assert = assert_lockmgr,
> +#ifdef DDB
> + .lc_ddb_show = db_show_lockmgr,
> +#endif
> + .lc_lock = lock_lockmgr,
> + .lc_unlock = unlock_lockmgr,
> +#ifdef KDTRACE_HOOKS
> + .lc_owner = owner_lockmgr,
> +#endif
> +};
> +
> +static void
> +assert_lockmgr(const struct lock_object *lock, int what)
> +{
> + panic("lockmgr locks do not support assertions");
> +}
This is neither the RTEMS style nor the FreeBSD style. At some point in
time it would be really nice to have a clang-format for RTEMS-specific code.
[...]
--
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