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clockintr: switch from callee- to caller-allocated clockintr structs

Currently, clockintr_establish() calls malloc(9) to allocate a
clockintr struct on behalf of the caller.  mpi@ says this behavior is
incompatible with dt(4).  In particular, calling malloc(9) during the
initialization of a PCB outside of dt_pcb_alloc() is (a) awkward and
(b) may conflict with future changes/optimizations to PCB allocation.

To side-step the problem, this patch changes the clockintr subsystem
to use caller-allocated clockintr structs instead of callee-allocated
structs.

clockintr_establish() is named after softintr_establish(), which uses
malloc(9) internally to create softintr objects.  The clockintr subsystem
is no longer using malloc(9), so the "establish" naming is no longer apt.
To avoid confusion, this patch also renames "clockintr_establish" to
"clockintr_bind".

Requested by mpi@.  Tweaked by mpi@.

Thread: https://marc.info/?l=openbsd-tech&m=170597126103504&w=2

ok claudio@ mlarkin@ mpi@

/*	$OpenBSD: subr_prof.c,v 1.41 2024/01/24 19:23:38 cheloha Exp $	*/
/*	$NetBSD: subr_prof.c,v 1.12 1996/04/22 01:38:50 christos Exp $	*/

/*-
 * Copyright (c) 1982, 1986, 1993
 *	The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)subr_prof.c	8.3 (Berkeley) 9/23/93
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/atomic.h>
#include <sys/clockintr.h>
#include <sys/pledge.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/syscallargs.h>
#include <sys/user.h>

uint64_t profclock_period;

#if defined(GPROF) || defined(DDBPROF)
#include <sys/malloc.h>
#include <sys/gmon.h>

#include <uvm/uvm_extern.h>

#include <machine/db_machdep.h>
#include <ddb/db_extern.h>

/*
 * Flag to prevent CPUs from executing the mcount() monitor function
 * until we're sure they are in a sane state.
 */
int gmoninit = 0;
u_int gmon_cpu_count;		/* [K] number of CPUs with profiling enabled */

extern char etext[];

void gmonclock(struct clockrequest *, void *, void *);

void
prof_init(void)
{
	CPU_INFO_ITERATOR cii;
	struct cpu_info *ci;
	struct gmonparam *p;
	u_long lowpc, highpc, textsize;
	u_long kcountsize, fromssize, tossize;
	long tolimit;
	char *cp;
	int size;

	/*
	 * Round lowpc and highpc to multiples of the density we're using
	 * so the rest of the scaling (here and in gprof) stays in ints.
	 */
	lowpc = ROUNDDOWN(KERNBASE, HISTFRACTION * sizeof(HISTCOUNTER));
	highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER));
	textsize = highpc - lowpc;
#ifdef GPROF
	printf("Profiling kernel, textsize=%ld [%lx..%lx]\n",
	    textsize, lowpc, highpc);
#endif
	kcountsize = textsize / HISTFRACTION;
	fromssize = textsize / HASHFRACTION;
	tolimit = textsize * ARCDENSITY / 100;
	if (tolimit < MINARCS)
		tolimit = MINARCS;
	else if (tolimit > MAXARCS)
		tolimit = MAXARCS;
	tossize = tolimit * sizeof(struct tostruct);
	size = sizeof(*p) + kcountsize + fromssize + tossize;

	/* Allocate and initialize one profiling buffer per CPU. */
	CPU_INFO_FOREACH(cii, ci) {
		cp = km_alloc(round_page(size), &kv_any, &kp_zero, &kd_nowait);
		if (cp == NULL) {
			printf("No memory for profiling.\n");
			return;
		}

		clockintr_bind(&ci->ci_gmonclock, ci, gmonclock, NULL);
		clockintr_stagger(&ci->ci_gmonclock, profclock_period,
		    CPU_INFO_UNIT(ci), MAXCPUS);

		p = (struct gmonparam *)cp;
		cp += sizeof(*p);
		p->tos = (struct tostruct *)cp;
		cp += tossize;
		p->kcount = (u_short *)cp;
		cp += kcountsize;
		p->froms = (u_short *)cp;

		p->state = GMON_PROF_OFF;
		p->lowpc = lowpc;
		p->highpc = highpc;
		p->textsize = textsize;
		p->hashfraction = HASHFRACTION;
		p->kcountsize = kcountsize;
		p->fromssize = fromssize;
		p->tolimit = tolimit;
		p->tossize = tossize;

		ci->ci_gmon = p;
	}
}

int
prof_state_toggle(struct cpu_info *ci, int oldstate)
{
	struct gmonparam *gp = ci->ci_gmon;
	int error = 0;

	KERNEL_ASSERT_LOCKED();

	if (gp->state == oldstate)
		return (0);

	switch (gp->state) {
	case GMON_PROF_ON:
#if !defined(GPROF)
		/*
		 * If this is not a profiling kernel, we need to patch
		 * all symbols that can be instrumented.
		 */
		error = db_prof_enable();
#endif
		if (error == 0) {
			if (++gmon_cpu_count == 1)
				startprofclock(&process0);
			clockintr_advance(&ci->ci_gmonclock, profclock_period);
		}
		break;
	default:
		error = EINVAL;
		gp->state = GMON_PROF_OFF;
		/* FALLTHROUGH */
	case GMON_PROF_OFF:
		clockintr_cancel(&ci->ci_gmonclock);
		if (--gmon_cpu_count == 0)
			stopprofclock(&process0);
#if !defined(GPROF)
		db_prof_disable();
#endif
		break;
	}

	return (error);
}

/*
 * Return kernel profiling information.
 */
int
sysctl_doprof(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
    size_t newlen)
{
	CPU_INFO_ITERATOR cii;
	struct cpu_info *ci;
	struct gmonparam *gp = NULL;
	int error, cpuid, op, state;

	/* all sysctl names at this level are name and field */
	if (namelen != 2)
		return (ENOTDIR);		/* overloaded */

	op = name[0];
	cpuid = name[1];

	CPU_INFO_FOREACH(cii, ci) {
		if (cpuid == CPU_INFO_UNIT(ci)) {
			gp = ci->ci_gmon;
			break;
		}
	}

	if (gp == NULL)
		return (EOPNOTSUPP);

	/* Assume that if we're here it is safe to execute profiling. */
	gmoninit = 1;

	switch (op) {
	case GPROF_STATE:
		state = gp->state;
		error = sysctl_int(oldp, oldlenp, newp, newlen, &gp->state);
		if (error)
			return (error);
		return prof_state_toggle(ci, state);
	case GPROF_COUNT:
		return (sysctl_struct(oldp, oldlenp, newp, newlen,
		    gp->kcount, gp->kcountsize));
	case GPROF_FROMS:
		return (sysctl_struct(oldp, oldlenp, newp, newlen,
		    gp->froms, gp->fromssize));
	case GPROF_TOS:
		return (sysctl_struct(oldp, oldlenp, newp, newlen,
		    gp->tos, gp->tossize));
	case GPROF_GMONPARAM:
		return (sysctl_rdstruct(oldp, oldlenp, newp, gp, sizeof *gp));
	default:
		return (EOPNOTSUPP);
	}
	/* NOTREACHED */
}

void
gmonclock(struct clockrequest *cr, void *cf, void *arg)
{
	uint64_t count;
	struct clockframe *frame = cf;
	struct gmonparam *g = curcpu()->ci_gmon;
	u_long i;

	count = clockrequest_advance(cr, profclock_period);
	if (count > ULONG_MAX)
		count = ULONG_MAX;

	/*
	 * Kernel statistics are just like addupc_intr(), only easier.
	 */
	if (!CLKF_USERMODE(frame) && g != NULL && g->state == GMON_PROF_ON) {
		i = CLKF_PC(frame) - g->lowpc;
		if (i < g->textsize) {
			i /= HISTFRACTION * sizeof(*g->kcount);
			g->kcount[i] += (u_long)count;
		}
	}
}

#endif /* GPROF || DDBPROF */

/*
 * Profiling system call.
 *
 * The scale factor is a fixed point number with 16 bits of fraction, so that
 * 1.0 is represented as 0x10000.  A scale factor of 0 turns off profiling.
 */
int
sys_profil(struct proc *p, void *v, register_t *retval)
{
	struct sys_profil_args /* {
		syscallarg(caddr_t) samples;
		syscallarg(size_t) size;
		syscallarg(u_long) offset;
		syscallarg(u_int) scale;
	} */ *uap = v;
	struct process *pr = p->p_p;
	struct uprof *upp;
	int error, s;

	error = pledge_profil(p, SCARG(uap, scale));
	if (error)
		return error;

	if (SCARG(uap, scale) > (1 << 16))
		return (EINVAL);
	if (SCARG(uap, scale) == 0) {
		stopprofclock(pr);
		need_resched(curcpu());
		return (0);
	}
	upp = &pr->ps_prof;

	/* Block profile interrupts while changing state. */
	s = splstatclock();
	upp->pr_off = SCARG(uap, offset);
	upp->pr_scale = SCARG(uap, scale);
	upp->pr_base = (caddr_t)SCARG(uap, samples);
	upp->pr_size = SCARG(uap, size);
	startprofclock(pr);
	splx(s);
	need_resched(curcpu());

	return (0);
}

void
profclock(struct clockrequest *cr, void *cf, void *arg)
{
	uint64_t count;
	struct clockframe *frame = cf;
	struct proc *p = curproc;

	count = clockrequest_advance(cr, profclock_period);
	if (count > ULONG_MAX)
		count = ULONG_MAX;

	if (CLKF_USERMODE(frame)) {
		if (ISSET(p->p_p->ps_flags, PS_PROFIL))
			addupc_intr(p, CLKF_PC(frame), (u_long)count);
	} else {
		if (p != NULL && ISSET(p->p_p->ps_flags, PS_PROFIL))
			addupc_intr(p, PROC_PC(p), (u_long)count);
	}
}

/*
 * Scale is a fixed-point number with the binary point 16 bits
 * into the value, and is <= 1.0.  pc is at most 32 bits, so the
 * intermediate result is at most 48 bits.
 */
#define	PC_TO_INDEX(pc, prof) \
	((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
	    (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)

/*
 * Collect user-level profiling statistics; called on a profiling tick,
 * when a process is running in user-mode.  This routine may be called
 * from an interrupt context. Schedule an AST that will vector us to
 * trap() with a context in which copyin and copyout will work.
 * Trap will then call addupc_task().
 */
void
addupc_intr(struct proc *p, u_long pc, u_long nticks)
{
	struct uprof *prof;

	prof = &p->p_p->ps_prof;
	if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size)
		return;			/* out of range; ignore */

	p->p_prof_addr = pc;
	p->p_prof_ticks += nticks;
	atomic_setbits_int(&p->p_flag, P_OWEUPC);
	need_proftick(p);
}


/*
 * Much like before, but we can afford to take faults here.  If the
 * update fails, we simply turn off profiling.
 */
void
addupc_task(struct proc *p, u_long pc, u_int nticks)
{
	struct process *pr = p->p_p;
	struct uprof *prof;
	caddr_t addr;
	u_int i;
	u_short v;

	/* Testing PS_PROFIL may be unnecessary, but is certainly safe. */
	if ((pr->ps_flags & PS_PROFIL) == 0 || nticks == 0)
		return;

	prof = &pr->ps_prof;
	if (pc < prof->pr_off ||
	    (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
		return;

	addr = prof->pr_base + i;
	if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) {
		v += nticks;
		if (copyout((caddr_t)&v, addr, sizeof(v)) == 0)
			return;
	}
	stopprofclock(pr);
}