> Date: Sun, 31 May 2020 00:25:00 -0400
> From: George Koehler <kern...@gmail.com>
>
> On Sat, 30 May 2020 19:21:30 +0300
> Paul Irofti <p...@irofti.net> wrote:
>
> > Here is an updated diff with no libc bump. Please use this one for
> > further testing.
>
> Your diff does amd64.
> Here is a diff to add macppc. Apply after your diff.
>
> I have only tested clock_gettime(2) with CLOCK_REALTIME,
> by doing loops in Ruby like, $ ruby27 -e '10000.times{p Time.now}'
> The time increased steadily, and ktrace showed only a few system calls
> to clock_gettime(2).
>
> I copied ppc_mftb() from /sys/arch/powerpc/powerpc/cpu.h and renamed
> it to tc_get_timecount_md(), because #include <machine/cpu.h> doesn't
> provide ppc_mftb() if not _KERNEL. It would be better to edit the
> kernel headers to give ppc_mftb() if _LIBC, but I haven't done that.
>
> I changed __amd64 to __amd64__ because I didn't find __powerpc. I'm
> not sure, but one might move the list of arches to dlfcn/Makefile.inc
> and do -DTIMEKEEP, like how thread/Makefile.inc does -DFUTEX. One
> might drop the tc_get_timecount function pointer and just always call
> the function #ifdef TIMEKEEP.
>
> PowerPC Mac OS X had a userland gettimeofday(2) using the cpu's
> timebase and a "common page" from the kernel. Their common page also
> had executable code for gettimeofday, memcpy, pthread_self, and a few
> other functions. --George
Oh, and on the diff itself:
> Index: lib/libc/arch/powerpc/gen/Makefile.inc
> ===================================================================
> RCS file: /cvs/src/lib/libc/arch/powerpc/gen/Makefile.inc,v
> retrieving revision 1.14
> diff -u -p -r1.14 Makefile.inc
> --- lib/libc/arch/powerpc/gen/Makefile.inc 12 Apr 2012 16:14:09 -0000
> 1.14
> +++ lib/libc/arch/powerpc/gen/Makefile.inc 31 May 2020 03:20:58 -0000
> @@ -3,3 +3,4 @@ SRCS+= fabs.c
> SRCS+= fpgetmask.c fpsetmask.c
> SRCS+= fpgetround.c fpsetround.c
> SRCS+= fpgetsticky.c fpsetsticky.c
> +SRCS+= usertc.c
> --- /dev/null Sat May 30 23:21:20 2020
> +++ lib/libc/arch/powerpc/gen/usertc.c Sat May 30 19:37:59 2020
> @@ -0,0 +1,44 @@
> +/* $OpenBSD$ */
> +/*
> + * Copyright (C) 1995, 1996 Wolfgang Solfrank.
> + * Copyright (C) 1995, 1996 TooLs GmbH.
> + * 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.
> + * 3. All advertising materials mentioning features or use of this software
> + * must display the following acknowledgement:
> + * This product includes software developed by TooLs GmbH.
> + * 4. The name of TooLs GmbH may not be used to endorse or promote products
> + * derived from this software without specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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/types.h>
> +
> +uint64_t
> +tc_get_timecount_md(void)
> +{
> + u_long scratch;
> + u_int64_t tb;
> +
> + __asm volatile ("1: mftbu %0; mftb %L0; mftbu %1;"
> + " cmpw 0,%0,%1; bne 1b" : "=r"(tb), "=r"(scratch));
> + return tb;
> +}
Would be good not to mux uint64_t and u_int64_t in the same bit of
code. I'd use uint64_t and replace u_long with uint32_t.
> --- lib/libc/dlfcn/init.c.before Sat May 30 23:26:35 2020
> +++ lib/libc/dlfcn/init.c Sat May 30 18:00:45 2020
> @@ -70,7 +70,7 @@
>
> /* provide definitions for these */
> const dl_cb *_dl_cb __relro = NULL;
> -#if defined(__amd64)
> +#if defined(__amd64__) || defined(__powerpc__)
> uint64_t (*const tc_get_timecount)(void) = tc_get_timecount_md;
> #else
> uint64_t (*const tc_get_timecount)(void) = NULL;
> --- sys/arch/macppc/macppc/clock.c.before Sat May 30 23:28:00 2020
> +++ sys/arch/macppc/macppc/clock.c Sat May 30 20:35:47 2020
> @@ -57,7 +57,7 @@
> static int32_t ticks_per_intr;
>
> static struct timecounter tb_timecounter = {
> - tb_get_timecount, NULL, 0x7fffffff, 0, "tb", 0, NULL, 0
> + tb_get_timecount, NULL, 0x7fffffff, 0, "tb", 0, NULL, 1
> };
>
> /* calibrate the timecounter frequency for the listed models */
>
