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Add arm_sync_icache() and arm_drain_writebuf() sysarch syscall wrappers.

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NetBSD and OpenBSD have libc wrapper functions for the ARM_SYNC_ICACHE and
ARM_DRAIN_WRITEBUF sysarch operations. This change adds compatible functions
to our library. This should make it easier for various upstream sources to
support *BSD operating systems with a single variation of cache maintence
code in tools like interpreters and JIT compilers.

I consider the argument types passed to arm_sync_icache() to be especially
unfortunate, but this is intended to match the other BSDs.

Differential Revision:	https://reviews.freebsd.org/D20906
This commit is contained in:
Ian Lepore 2019-07-13 15:34:29 +00:00
parent f7e8f5d439
commit 805eb13a60
7 changed files with 251 additions and 1 deletions
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5
lib/libc/arm/Symbol.map
View File

@ -41,6 +41,11 @@ FBSD_1.4 {
dl_unwind_find_exidx;
};
FBSD_1.6 {
arm_drain_writebuf;
arm_sync_icache;
};
FBSDprivate_1.0 {
/* PSEUDO syscalls */
_getlogin;

6
lib/libc/arm/gen/Makefile.inc
View File

@ -8,6 +8,8 @@ SRCS+= \
_setjmp.S \
alloca.S \
arm_initfini.c \
arm_drain_writebuf.c \
arm_sync_icache.c \
fabs.c \
flt_rounds.c \
getcontextx.c \
@ -18,6 +20,10 @@ SRCS+= \
signalcontext.c \
sigsetjmp.S \
MAN+= \
arm_drain_writebuf.2 \
arm_sync_icache.2 \
.if ${MACHINE_ARCH:Marmv[67]*} && (!defined(CPUTYPE) || ${CPUTYPE:M*soft*} == "")
SRCS+= \

77
lib/libc/arm/gen/arm_drain_writebuf.2 Normal file
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@ -0,0 +1,77 @@
.\" Copyright (c) 2019 Ian Lepore <ian@FreeBSD.org>
.\"
.\" 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 AUTHORS 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 AUTHORS 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.
.\"
.\" $FreeBSD$
.\"
.Dd July 10, 2019
.Dt ARM_DRAIN_WRITEBUF 2
.Os
.Sh NAME
.Nm arm_drain_writebuf
.Nd drain pending writes from cores and caches
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In machine/sysarch.h
.Ft int
.Fn arm_drain_writebuf void
.Sh DESCRIPTION
The
.Nm
system call causes all pending writes from ARM cores and caches to be
written out to main memory or memory-mapped I/O registers.
Not all hardware supports buffered writes; on such systems the
.Nm
function is a no-op.
.Pp
On ARMv5 systems, this executes a cp15 coprocessor
.Dq drain write buffer
operation.
On ARMv6 and ARMv7 systems, this executes a
.Dq DSB SY
synchronization barrier, followed by an L2 cache drain on
systems where the DSB does not include L2 automatically.
.Pp
.Nm
attempts to wait for the drain operation to complete, but cannot
guarantee the writes have reached their ultimate destination on all hardware.
For example, on an ARMv7 system,
.Nm
tells the L2 cache controller to drain its buffers, and it waits until
the controller indicates that operation is complete.
However, all the L2 controller knows is that the data was accepted for
delivery by the AXI bus.
If the ultimate destination of the write is a device on a subordinate
bus connected to the AXI bus, more buffering or other delays may occur
on that subordinate bus.
The only way to be certain a pending write has reached its
ultimate destination is to issue a read from that destination after
.Nm
returns.
.Sh RETURN VALUES
The
.Nm
system call cannot fail, and always returns 0.
.Sh AUTHORS
This man page was written by
.An Ian Lepore .

39
lib/libc/arm/gen/arm_drain_writebuf.c Normal file
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@ -0,0 +1,39 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@FreeBSD.org>
*
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <machine/sysarch.h>
#include <stddef.h>
int
arm_drain_writebuf(void)
{
sysarch(ARM_DRAIN_WRITEBUF, NULL);
return (0);
}

79
lib/libc/arm/gen/arm_sync_icache.2 Normal file
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@ -0,0 +1,79 @@
.\" Copyright (c) 2019 Ian Lepore <ian@FreeBSD.org>
.\"
.\" 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 AUTHORS 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 AUTHORS 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.
.\"
.\" $FreeBSD$
.\"
.Dd July 10, 2019
.Dt ARM_sync_icache 2
.Os
.Sh NAME
.Nm arm_sync_icache
.Nd synchronize the data and instruction caches
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In machine/sysarch.h
.Ft int
.Fn arm_sync_icache "u_int addr" "int len"
.Sh DESCRIPTION
The
.Nm
system call synchronizes the contents of any data and instructions caches
with the contents of main memory for the given range.
Use this after loading executable code or modifying existing code in memory,
before attempting to execute that code.
.Pp
The
.Va addr
and
.Va len
arguments do not need to be aligned to any particular boundary, but
cache operations will affect entire cache lines, even those which are only
partially overlapped by the given range.
.Pp
This takes one or more of the following actions, depending on the requirements
of the hardware:
.Bl -bullet
.It
Write dirty data cache lines within the range back to main memory.
.It
Invalidate existing instruction cache contents for the range.
.It
Invalidate branch prediction caches for the range.
.El
.Pp
On hardware which supports multiple synchronization points for cache
operations, the caches are maintained to the point of unification,
making the data in the range coherent amongst all cores.
.Sh RETURN VALUES
The
.Nm
system call always returns 0.
.Sh ERRORS
If a call refers to memory which the calling process does not have rights
to access, or if the
.Va len
argument is negative, a SIGSEGV signal is delivered to the calling thread.
.Sh AUTHORS
This man page was written by
.An Ian Lepore .

44
lib/libc/arm/gen/arm_sync_icache.c Normal file
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@ -0,0 +1,44 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@FreeBSD.org>
*
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <machine/sysarch.h>
#include <stddef.h>
int
arm_sync_icache(u_int addr, int len)
{
struct arm_sync_icache_args args;
args.addr = addr;
args.len = len;
sysarch(ARM_SYNC_ICACHE, &args);
return (0);
}

2
sys/sys/param.h
View File

@ -60,7 +60,7 @@
* in the range 5 to 9.
*/
#undef __FreeBSD_version
#define __FreeBSD_version 1300035 /* Master, propagated to newvers */
#define __FreeBSD_version 1300036 /* Master, propagated to newvers */
/*
* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,