/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1996 Bruce D. Evans.
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifdef GUPROF
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/eventhandler.h>
#include <sys/gmon.h>
#include <sys/kernel.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <machine/clock.h>
#include <machine/timerreg.h>
#define CPUTIME_CLOCK_UNINITIALIZED 0
#define CPUTIME_CLOCK_I8254 1
#define CPUTIME_CLOCK_TSC 2
#define CPUTIME_CLOCK_I8254_SHIFT 7
int cputime_bias = 1; /* initialize for locality of reference */
static int cputime_clock = CPUTIME_CLOCK_UNINITIALIZED;
static int cputime_prof_active;
#endif /* GUPROF */
#ifdef __GNUCLIKE_ASM
__asm(" \n\
GM_STATE = 0 \n\
GMON_PROF_OFF = 3 \n\
\n\
.text \n\
.p2align 4,0x90 \n\
.globl __mcount \n\
.type __mcount,@function \n\
__mcount: \n\
# \n\
# Check that we are profiling. Do it early for speed. \n\
# \n\
cmpl $GMON_PROF_OFF,_gmonparam+GM_STATE \n\
je .mcount_exit \n\
# \n\
# __mcount is the same as [.]mcount except the caller \n\
# hasn't changed the stack except to call here, so the \n\
# caller's raddr is above our raddr. \n\
# \n\
pushq %rax \n\
pushq %rdx \n\
pushq %rcx \n\
pushq %rsi \n\
pushq %rdi \n\
pushq %r8 \n\
pushq %r9 \n\
movq 7*8+8(%rsp),%rdi \n\
jmp .got_frompc \n\
\n\
.p2align 4,0x90 \n\
.globl .mcount \n\
.mcount: \n\
cmpl $GMON_PROF_OFF,_gmonparam+GM_STATE \n\
je .mcount_exit \n\
# \n\
# The caller's stack frame has already been built, so \n\
# %rbp is the caller's frame pointer. The caller's \n\
# raddr is in the caller's frame following the caller's \n\
# caller's frame pointer. \n\
# \n\
pushq %rax \n\
pushq %rdx \n\
pushq %rcx \n\
pushq %rsi \n\
pushq %rdi \n\
pushq %r8 \n\
pushq %r9 \n\
movq 8(%rbp),%rdi \n\
.got_frompc: \n\
# \n\
# Our raddr is the caller's pc. \n\
# \n\
movq 7*8(%rsp),%rsi \n\
\n\
pushfq \n\
cli \n\
call mcount \n\
popfq \n\
popq %r9 \n\
popq %r8 \n\
popq %rdi \n\
popq %rsi \n\
popq %rcx \n\
popq %rdx \n\
popq %rax \n\
.mcount_exit: \n\
ret $0 \n\
");
#else /* !__GNUCLIKE_ASM */
#error "this file needs to be ported to your compiler"
#endif /* __GNUCLIKE_ASM */
#ifdef GUPROF
/*
* [.]mexitcount saves the return register(s), loads selfpc and calls
* mexitcount(selfpc) to do the work. Someday it should be in a machine
* dependent file together with cputime(), __mcount and [.]mcount. cputime()
* can't just be put in machdep.c because it has to be compiled without -pg.
*/
#ifdef __GNUCLIKE_ASM
__asm(" \n\
.text \n\
# \n\
# Dummy label to be seen when gprof -u hides [.]mexitcount. \n\
# \n\
.p2align 4,0x90 \n\
.globl __mexitcount \n\
.type __mexitcount,@function \n\
__mexitcount: \n\
nop \n\
\n\
GMON_PROF_HIRES = 4 \n\
\n\
.p2align 4,0x90 \n\
.globl .mexitcount \n\
.mexitcount: \n\
cmpl $GMON_PROF_HIRES,_gmonparam+GM_STATE \n\
jne .mexitcount_exit \n\
pushq %rax \n\
pushq %rdx \n\
pushq %rcx \n\
pushq %rsi \n\
pushq %rdi \n\
pushq %r8 \n\
pushq %r9 \n\
movq 7*8(%rsp),%rdi \n\
pushfq \n\
cli \n\
call mexitcount \n\
popfq \n\
popq %r9 \n\
popq %r8 \n\
popq %rdi \n\
popq %rsi \n\
popq %rcx \n\
popq %rdx \n\
popq %rax \n\
.mexitcount_exit: \n\
ret $0 \n\
");
#endif /* __GNUCLIKE_ASM */
/*
* Return the time elapsed since the last call. The units are machine-
* dependent.
*/
int
cputime()
{
u_int count;
int delta;
u_char high, low;
static u_int prev_count;
if (cputime_clock == CPUTIME_CLOCK_TSC) {
/*
* Scale the TSC a little to make cputime()'s frequency
* fit in an int, assuming that the TSC frequency fits
* in a u_int. Use a fixed scale since dynamic scaling
* would be slower and we can't really use the low bit
* of precision.
*/
count = (u_int)rdtsc() & ~1u;
delta = (int)(count - prev_count) >> 1;
prev_count = count;
return (delta);
}
/*
* Read the current value of the 8254 timer counter 0.
*/
outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
low = inb(TIMER_CNTR0);
high = inb(TIMER_CNTR0);
count = ((high << 8) | low) << CPUTIME_CLOCK_I8254_SHIFT;
/*
* The timer counts down from TIMER_CNTR0_MAX to 0 and then resets.
* While profiling is enabled, this routine is called at least twice
* per timer reset (for mcounting and mexitcounting hardclock()),
* so at most one reset has occurred since the last call, and one
* has occurred iff the current count is larger than the previous
* count. This allows counter underflow to be detected faster
* than in microtime().
*/
delta = prev_count - count;
prev_count = count;
if ((int) delta <= 0)
return (delta + (i8254_max_count << CPUTIME_CLOCK_I8254_SHIFT));
return (delta);
}
static int
sysctl_machdep_cputime_clock(SYSCTL_HANDLER_ARGS)
{
int clock;
int error;
clock = cputime_clock;
error = sysctl_handle_opaque(oidp, &clock, sizeof clock, req);
if (error == 0 && req->newptr != NULL) {
if (clock < 0 || clock > CPUTIME_CLOCK_TSC)
return (EINVAL);
cputime_clock = clock;
}
return (error);
}
SYSCTL_PROC(_machdep, OID_AUTO, cputime_clock, CTLTYPE_INT | CTLFLAG_RW,
0, sizeof(u_int), sysctl_machdep_cputime_clock, "I", "");
/*
* The start and stop routines need not be here since we turn off profiling
* before calling them. They are here for convenience.
*/
void
startguprof(gp)
struct gmonparam *gp;
{
uint64_t freq;
freq = atomic_load_acq_64(&tsc_freq);
if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
if (freq != 0 && mp_ncpus == 1)
cputime_clock = CPUTIME_CLOCK_TSC;
else
cputime_clock = CPUTIME_CLOCK_I8254;
}
if (cputime_clock == CPUTIME_CLOCK_TSC) {
gp->profrate = freq >> 1;
cputime_prof_active = 1;
} else
gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
cputime_bias = 0;
cputime();
}
void
stopguprof(gp)
struct gmonparam *gp;
{
if (cputime_clock == CPUTIME_CLOCK_TSC)
cputime_prof_active = 0;
}
/* If the cpu frequency changed while profiling, report a warning. */
static void
tsc_freq_changed(void *arg, const struct cf_level *level, int status)
{
/*
* If there was an error during the transition or
* TSC is P-state invariant, don't do anything.
*/
if (status != 0 || tsc_is_invariant)
return;
if (cputime_prof_active && cputime_clock == CPUTIME_CLOCK_TSC)
printf("warning: cpu freq changed while profiling active\n");
}
EVENTHANDLER_DEFINE(cpufreq_post_change, tsc_freq_changed, NULL,
EVENTHANDLER_PRI_ANY);
#endif /* GUPROF */
