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NetBSD/sys/uvm/pmap/pmap_tlb.c

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/* $NetBSD: pmap_tlb.c,v 1.62 2024/01/01 16:56:30 skrll Exp $ */
/*-
* Copyright (c) 2010 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas at 3am Software Foundry.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__KERNEL_RCSID(0, "$NetBSD: pmap_tlb.c,v 1.62 2024/01/01 16:56:30 skrll Exp $");
/*
* Manages address spaces in a TLB.
*
* Normally there is a 1:1 mapping between a TLB and a CPU. However, some
* implementations may share a TLB between multiple CPUs (really CPU thread
* contexts). This requires the TLB abstraction to be separated from the
* CPU abstraction. It also requires that the TLB be locked while doing
* TLB activities.
*
* For each TLB, we track the ASIDs in use in a bitmap and a list of pmaps
* that have a valid ASID.
*
* We allocate ASIDs in increasing order until we have exhausted the supply,
* then reinitialize the ASID space, and start allocating again at 1. When
* allocating from the ASID bitmap, we skip any ASID who has a corresponding
* bit set in the ASID bitmap. Eventually this causes the ASID bitmap to fill
* and, when completely filled, a reinitialization of the ASID space.
*
* To reinitialize the ASID space, the ASID bitmap is reset and then the ASIDs
* of non-kernel TLB entries get recorded in the ASID bitmap. If the entries
* in TLB consume more than half of the ASID space, all ASIDs are invalidated,
* the ASID bitmap is recleared, and the list of pmaps is emptied. Otherwise,
* (the normal case), any ASID present in the TLB (even those which are no
* longer used by a pmap) will remain active (allocated) and all other ASIDs
* will be freed. If the size of the TLB is much smaller than the ASID space,
* this algorithm completely avoids TLB invalidation.
*
* For multiprocessors, we also have to deal TLB invalidation requests from
* other CPUs, some of which are dealt with the reinitialization of the ASID
* space. Whereas above we keep the ASIDs of those pmaps which have active
* TLB entries, this type of reinitialization preserves the ASIDs of any
* "onproc" user pmap and all other ASIDs will be freed. We must do this
* since we can't change the current ASID.
*
* Each pmap has two bitmaps: pm_active and pm_onproc. Each bit in pm_active
* indicates whether that pmap has an allocated ASID for a CPU. Each bit in
* pm_onproc indicates that the pmap's ASID is in use, i.e. a CPU has it in its
* "current ASID" field, e.g. the ASID field of the COP 0 register EntryHi for
* MIPS, or the ASID field of TTBR0 for AA64. The bit number used in these
* bitmaps comes from the CPU's cpu_index(). Even though these bitmaps contain
* the bits for all CPUs, the bits that correspond to the bits belonging to
* the CPUs sharing a TLB can only be manipulated while holding that TLB's
* lock. Atomic ops must be used to update them since multiple CPUs may be
* changing different sets of bits at same time but these sets never overlap.
*
* When a change to the local TLB may require a change in the TLB's of other
* CPUs, we try to avoid sending an IPI if at all possible. For instance, if
* we are updating a PTE and that PTE previously was invalid and therefore
* couldn't support an active mapping, there's no need for an IPI since there
* can't be a TLB entry to invalidate. The other case is when we change a PTE
* to be modified we just update the local TLB. If another TLB has a stale
* entry, a TLB MOD exception will be raised and that will cause the local TLB
* to be updated.
*
* We never need to update a non-local TLB if the pmap doesn't have a valid
* ASID for that TLB. If it does have a valid ASID but isn't current "onproc"
* we simply reset its ASID for that TLB and then when it goes "onproc" it
* will allocate a new ASID and any existing TLB entries will be orphaned.
* Only in the case that pmap has an "onproc" ASID do we actually have to send
* an IPI.
*
* Once we determined we must send an IPI to shootdown a TLB, we need to send
* it to one of CPUs that share that TLB. We choose the lowest numbered CPU
* that has one of the pmap's ASID "onproc". In reality, any CPU sharing that
* TLB would do, but interrupting an active CPU seems best.
*
* A TLB might have multiple shootdowns active concurrently. The shootdown
* logic compresses these into a few cases:
* 0) nobody needs to have its TLB entries invalidated
* 1) one ASID needs to have its TLB entries invalidated
* 2) more than one ASID needs to have its TLB entries invalidated
* 3) the kernel needs to have its TLB entries invalidated
* 4) the kernel and one or more ASID need their TLB entries invalidated.
*
* And for each case we do:
* 0) nothing,
* 1) if that ASID is still "onproc", we invalidate the TLB entries for
* that single ASID. If not, just reset the pmap's ASID to invalidate
* and let it allocate a new ASID the next time it goes "onproc",
* 2) we reinitialize the ASID space (preserving any "onproc" ASIDs) and
* invalidate all non-wired non-global TLB entries,
* 3) we invalidate all of the non-wired global TLB entries,
* 4) we reinitialize the ASID space (again preserving any "onproc" ASIDs)
* invalidate all non-wired TLB entries.
*
* As you can see, shootdowns are not concerned with addresses, just address
* spaces. Since the number of TLB entries is usually quite small, this avoids
* a lot of overhead for not much gain.
*/
#define __PMAP_PRIVATE
#include "opt_multiprocessor.h"
#include <sys/param.h>
#include <sys/atomic.h>
#include <sys/cpu.h>
#include <sys/kernel.h> /* for cold */
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <uvm/uvm.h>
static kmutex_t pmap_tlb0_lock __cacheline_aligned;
#define IFCONSTANT(x) (__builtin_constant_p((x)) ? (x) : 0)
#if KERNEL_PID > 31
#error "KERNEL_PID expected in range 0-31"
#endif
#define TLBINFO_ASID_MARK_UNUSED(ti, asid) \
__BITMAP_CLR((asid), &(ti)->ti_asid_bitmap)
#define TLBINFO_ASID_MARK_USED(ti, asid) \
__BITMAP_SET((asid), &(ti)->ti_asid_bitmap)
#define TLBINFO_ASID_INUSE_P(ti, asid) \
__BITMAP_ISSET((asid), &(ti)->ti_asid_bitmap)
#define TLBINFO_ASID_RESET(ti) \
do { \
__BITMAP_ZERO(&ti->ti_asid_bitmap); \
for (tlb_asid_t asid = 0; asid <= KERNEL_PID; asid++) \
TLBINFO_ASID_MARK_USED(ti, asid); \
} while (0)
#define TLBINFO_ASID_INITIAL_FREE(asid_max) \
(asid_max + 1 /* 0 */ - (1 + KERNEL_PID))
struct pmap_tlb_info pmap_tlb0_info = {
.ti_name = "tlb0",
.ti_asid_hint = KERNEL_PID + 1,
#ifdef PMAP_TLB_NUM_PIDS
.ti_asid_max = IFCONSTANT(PMAP_TLB_NUM_PIDS - 1),
.ti_asids_free = IFCONSTANT(
TLBINFO_ASID_INITIAL_FREE(PMAP_TLB_NUM_PIDS - 1)),
#endif
.ti_asid_bitmap._b[0] = __BITS(0, KERNEL_PID),
#ifdef PMAP_TLB_WIRED_UPAGES
.ti_wired = PMAP_TLB_WIRED_UPAGES,
#endif
.ti_lock = &pmap_tlb0_lock,
.ti_pais = LIST_HEAD_INITIALIZER(pmap_tlb0_info.ti_pais),
#if defined(MULTIPROCESSOR) && PMAP_TLB_MAX > 1
.ti_tlbinvop = TLBINV_NOBODY,
#endif
};
#undef IFCONSTANT
#if defined(MULTIPROCESSOR) && PMAP_TLB_MAX > 1
struct pmap_tlb_info *pmap_tlbs[PMAP_TLB_MAX] = {
[0] = &pmap_tlb0_info,
};
u_int pmap_ntlbs = 1;
#endif
#ifdef MULTIPROCESSOR
__unused static inline bool
pmap_tlb_intersecting_active_p(pmap_t pm, struct pmap_tlb_info *ti)
{
#if PMAP_TLB_MAX == 1
return !kcpuset_iszero(pm->pm_active);
#else
return kcpuset_intersecting_p(pm->pm_active, ti->ti_kcpuset);
#endif
}
static inline bool
pmap_tlb_intersecting_onproc_p(pmap_t pm, struct pmap_tlb_info *ti)
{
#if PMAP_TLB_MAX == 1
return !kcpuset_iszero(pm->pm_onproc);
#else
return kcpuset_intersecting_p(pm->pm_onproc, ti->ti_kcpuset);
#endif
}
#endif
static void
pmap_tlb_pai_check(struct pmap_tlb_info *ti, bool locked_p)
{
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, "(ti=%#jx)", (uintptr_t)ti, 0, 0, 0);
#ifdef DIAGNOSTIC
struct pmap_asid_info *pai;
if (!locked_p)
TLBINFO_LOCK(ti);
LIST_FOREACH(pai, &ti->ti_pais, pai_link) {
KASSERT(pai != NULL);
KASSERT(PAI_PMAP(pai, ti) != pmap_kernel());
KASSERT(pai->pai_asid > KERNEL_PID);
KASSERTMSG(pai->pai_asid <= ti->ti_asid_max,
"pm %p asid %#x", PAI_PMAP(pai, ti), pai->pai_asid);
KASSERTMSG(TLBINFO_ASID_INUSE_P(ti, pai->pai_asid),
"pm %p asid %u", PAI_PMAP(pai, ti), pai->pai_asid);
#ifdef MULTIPROCESSOR
KASSERT(pmap_tlb_intersecting_active_p(PAI_PMAP(pai, ti), ti));
#endif
}
if (!locked_p)
TLBINFO_UNLOCK(ti);
#endif
UVMHIST_LOG(maphist, " <-- done", 0, 0, 0, 0);
}
static void
pmap_tlb_pai_reset(struct pmap_tlb_info *ti, struct pmap_asid_info *pai,
struct pmap *pm)
{
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, "(ti=%#jx, pai=%#jx, pm=%#jx): asid %u",
(uintptr_t)ti, (uintptr_t)pai, (uintptr_t)pm, pai->pai_asid);
/*
* We must have an ASID but it must not be onproc (on a processor).
*/
KASSERT(pai->pai_asid > KERNEL_PID);
KASSERT(pai->pai_asid <= ti->ti_asid_max);
#if defined(MULTIPROCESSOR)
KASSERT(pmap_tlb_intersecting_active_p(pm, ti));
KASSERT(!pmap_tlb_intersecting_onproc_p(pm, ti));
#endif
LIST_REMOVE(pai, pai_link);
#ifdef DIAGNOSTIC
pai->pai_link.le_prev = NULL; /* tagged as unlinked */
#endif
/*
* If the platform has a cheap way to flush ASIDs then free the ASID
* back into the pool. On multiprocessor systems, we will flush the
* ASID from the TLB when it's allocated. That way we know the flush
* was always done in the correct TLB space. On uniprocessor systems,
* just do the flush now since we know that it has been used. This has
* a bit less overhead. Either way, this will mean that we will only
* need to flush all ASIDs if all ASIDs are in use and we need to
* allocate a new one.
*/
if (PMAP_TLB_FLUSH_ASID_ON_RESET) {
#ifndef MULTIPROCESSOR
UVMHIST_LOG(maphist, " ... asid %u flushed", pai->pai_asid, 0,
0, 0);
tlb_invalidate_asids(pai->pai_asid, pai->pai_asid);
#endif
if (TLBINFO_ASID_INUSE_P(ti, pai->pai_asid)) {
UVMHIST_LOG(maphist, " ... asid marked unused",
pai->pai_asid, 0, 0, 0);
TLBINFO_ASID_MARK_UNUSED(ti, pai->pai_asid);
ti->ti_asids_free++;
}
}
/*
* Note that we don't mark the ASID as not in use in the TLB's ASID
* bitmap (thus it can't be allocated until the ASID space is exhausted
* and therefore reinitialized). We don't want to flush the TLB for
* entries belonging to this ASID so we will let natural TLB entry
* replacement flush them out of the TLB. Any new entries for this
* pmap will need a new ASID allocated.
*/
pai->pai_asid = 0;
#if defined(MULTIPROCESSOR)
/*
* The bits in pm_active belonging to this TLB can only be changed
* while this TLB's lock is held.
*/
#if PMAP_TLB_MAX == 1
kcpuset_zero(pm->pm_active);
#else
kcpuset_remove(pm->pm_active, ti->ti_kcpuset);
#endif
KASSERT(!pmap_tlb_intersecting_active_p(pm, ti));
#endif /* MULTIPROCESSOR */
UVMHIST_LOG(maphist, " <-- done", 0, 0, 0, 0);
}
void
pmap_tlb_info_evcnt_attach(struct pmap_tlb_info *ti)
{
#if defined(MULTIPROCESSOR) && !defined(PMAP_TLB_NO_SYNCI_EVCNT)
evcnt_attach_dynamic_nozero(&ti->ti_evcnt_synci_desired,
EVCNT_TYPE_MISC, NULL,
ti->ti_name, "icache syncs desired");
evcnt_attach_dynamic_nozero(&ti->ti_evcnt_synci_asts,
EVCNT_TYPE_MISC, &ti->ti_evcnt_synci_desired,
ti->ti_name, "icache sync asts");
evcnt_attach_dynamic_nozero(&ti->ti_evcnt_synci_all,
EVCNT_TYPE_MISC, &ti->ti_evcnt_synci_asts,
ti->ti_name, "icache full syncs");
evcnt_attach_dynamic_nozero(&ti->ti_evcnt_synci_pages,
EVCNT_TYPE_MISC, &ti->ti_evcnt_synci_asts,
ti->ti_name, "icache pages synced");
evcnt_attach_dynamic_nozero(&ti->ti_evcnt_synci_duplicate,
EVCNT_TYPE_MISC, &ti->ti_evcnt_synci_desired,
ti->ti_name, "icache dup pages skipped");
evcnt_attach_dynamic_nozero(&ti->ti_evcnt_synci_deferred,
EVCNT_TYPE_MISC, &ti->ti_evcnt_synci_desired,
ti->ti_name, "icache pages deferred");
#endif /* MULTIPROCESSOR && !PMAP_TLB_NO_SYNCI_EVCNT */
evcnt_attach_dynamic_nozero(&ti->ti_evcnt_asid_reinits,
EVCNT_TYPE_MISC, NULL,
ti->ti_name, "asid pool reinit");
}
void
pmap_tlb_info_init(struct pmap_tlb_info *ti)
{
#if defined(MULTIPROCESSOR)
#if PMAP_TLB_MAX == 1
KASSERT(ti == &pmap_tlb0_info);
#else
if (ti != &pmap_tlb0_info) {
KASSERT(pmap_ntlbs < PMAP_TLB_MAX);
KASSERT(pmap_tlbs[pmap_ntlbs] == NULL);
ti->ti_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SCHED);
TLBINFO_ASID_RESET(ti);
ti->ti_asid_hint = KERNEL_PID + 1;
ti->ti_asid_max = pmap_tlbs[0]->ti_asid_max;
ti->ti_asids_free = TLBINFO_ASID_INITIAL_FREE(ti->ti_asid_max);
ti->ti_tlbinvop = TLBINV_NOBODY;
ti->ti_victim = NULL;
kcpuset_create(&ti->ti_kcpuset, true);
ti->ti_index = pmap_ntlbs++;
ti->ti_wired = 0;
pmap_tlbs[ti->ti_index] = ti;
snprintf(ti->ti_name, sizeof(ti->ti_name), "tlb%u",
ti->ti_index);
pmap_tlb_info_evcnt_attach(ti);
KASSERT(ti->ti_asid_max < PMAP_TLB_BITMAP_LENGTH);
return;
}
#endif
#endif /* MULTIPROCESSOR */
KASSERT(ti == &pmap_tlb0_info);
KASSERT(ti->ti_lock == &pmap_tlb0_lock);
mutex_init(ti->ti_lock, MUTEX_DEFAULT, IPL_SCHED);
#if defined(MULTIPROCESSOR) && PMAP_TLB_MAX > 1
kcpuset_create(&ti->ti_kcpuset, true);
kcpuset_set(ti->ti_kcpuset, cpu_index(curcpu()));
#endif
const tlb_asid_t asid_max = pmap_md_tlb_asid_max();
if (ti->ti_asid_max == 0 || asid_max < ti->ti_asid_max) {
ti->ti_asid_max = asid_max;
ti->ti_asids_free = TLBINFO_ASID_INITIAL_FREE(ti->ti_asid_max);
}
KASSERT(__type_fit(tlb_asid_t, ti->ti_asid_max + 1));
KASSERT(ti->ti_asid_max < PMAP_TLB_BITMAP_LENGTH);
}
#if defined(MULTIPROCESSOR)
void
pmap_tlb_info_attach(struct pmap_tlb_info *ti, struct cpu_info *ci)
{
KASSERT(!CPU_IS_PRIMARY(ci));
KASSERT(ci->ci_data.cpu_idlelwp != NULL);
KASSERT(cold);
TLBINFO_LOCK(ti);
#if PMAP_TLB_MAX > 1
kcpuset_set(ti->ti_kcpuset, cpu_index(ci));
cpu_set_tlb_info(ci, ti);
#endif
/*
* Do any MD tlb info init.
*/
pmap_md_tlb_info_attach(ti, ci);
/*
* The kernel pmap uses the kcpuset_running set so it's always
* up-to-date.
*/
TLBINFO_UNLOCK(ti);
}
#endif /* MULTIPROCESSOR */
#ifdef DIAGNOSTIC
static size_t
pmap_tlb_asid_count(struct pmap_tlb_info *ti)
{
size_t count = 0;
for (tlb_asid_t asid = 1; asid <= ti->ti_asid_max; asid++) {
if (TLBINFO_ASID_INUSE_P(ti, asid))
count++;
}
return count;
}
#endif
static void
pmap_tlb_asid_reinitialize(struct pmap_tlb_info *ti, enum tlb_invalidate_op op)
{
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, "(ti=%#jx, op=%ju)", (uintptr_t)ti, op, 0, 0);
pmap_tlb_pai_check(ti, true);
ti->ti_evcnt_asid_reinits.ev_count++;
/*
* First, clear the ASID bitmap (except for ASID 0 which belongs
* to the kernel).
*/
ti->ti_asids_free = TLBINFO_ASID_INITIAL_FREE(ti->ti_asid_max);
ti->ti_asid_hint = KERNEL_PID + 1;
TLBINFO_ASID_RESET(ti);
switch (op) {
#if defined(MULTIPROCESSOR) && defined(PMAP_TLB_NEED_SHOOTDOWN)
case TLBINV_ALL:
tlb_invalidate_all();
break;
case TLBINV_ALLUSER:
tlb_invalidate_asids(KERNEL_PID + 1, ti->ti_asid_max);
break;
#endif /* MULTIPROCESSOR && PMAP_TLB_NEED_SHOOTDOWN */
case TLBINV_NOBODY: {
/*
* If we are just reclaiming ASIDs in the TLB, let's go find
* what ASIDs are in use in the TLB. Since this is a
* semi-expensive operation, we don't want to do it too often.
* So if more half of the ASIDs are in use, we don't have
* enough free ASIDs so invalidate the TLB entries with ASIDs
* and clear the ASID bitmap. That will force everyone to
* allocate a new ASID.
*/
#if !defined(MULTIPROCESSOR) || defined(PMAP_TLB_NEED_SHOOTDOWN)
pmap_tlb_asid_check();
const u_int asids_found = tlb_record_asids(
ti->ti_asid_bitmap._b, ti->ti_asid_max);
pmap_tlb_asid_check();
#ifdef DIAGNOSTIC
const u_int asids_count = pmap_tlb_asid_count(ti);
KASSERTMSG(asids_found == asids_count,
"found %u != count %u", asids_found, asids_count);
#endif
if (__predict_false(asids_found >= ti->ti_asid_max / 2)) {
tlb_invalidate_asids(KERNEL_PID + 1, ti->ti_asid_max);
#else /* MULTIPROCESSOR && !PMAP_TLB_NEED_SHOOTDOWN */
/*
* For those systems (PowerPC) that don't require
* cross cpu TLB shootdowns, we have to invalidate the
* entire TLB because we can't record the ASIDs in use
* on the other CPUs. This is hopefully cheaper than
* than trying to use an IPI to record all the ASIDs
* on all the CPUs (which would be a synchronization
* nightmare).
*/
tlb_invalidate_all();
#endif /* MULTIPROCESSOR && !PMAP_TLB_NEED_SHOOTDOWN */
TLBINFO_ASID_RESET(ti);
ti->ti_asids_free = TLBINFO_ASID_INITIAL_FREE(
ti->ti_asid_max);
#if !defined(MULTIPROCESSOR) || defined(PMAP_TLB_NEED_SHOOTDOWN)
} else {
ti->ti_asids_free -= asids_found;
}
#endif /* !MULTIPROCESSOR || PMAP_TLB_NEED_SHOOTDOWN */
KASSERTMSG(ti->ti_asids_free <= ti->ti_asid_max, "%u",
ti->ti_asids_free);
break;
}
default:
panic("%s: unexpected op %d", __func__, op);
}
/*
* Now go through the active ASIDs. If the ASID is on a processor or
* we aren't invalidating all ASIDs and the TLB has an entry owned by
* that ASID, mark it as in use. Otherwise release the ASID.
*/
struct pmap_asid_info *pai, *next;
for (pai = LIST_FIRST(&ti->ti_pais); pai != NULL; pai = next) {
struct pmap * const pm = PAI_PMAP(pai, ti);
next = LIST_NEXT(pai, pai_link);
KASSERT(pm != pmap_kernel());
KASSERT(pai->pai_asid > KERNEL_PID);
#if defined(MULTIPROCESSOR)
if (pmap_tlb_intersecting_onproc_p(pm, ti)) {
if (!TLBINFO_ASID_INUSE_P(ti, pai->pai_asid)) {
TLBINFO_ASID_MARK_USED(ti, pai->pai_asid);
ti->ti_asids_free--;
}
continue;
}
#endif /* MULTIPROCESSOR */
if (TLBINFO_ASID_INUSE_P(ti, pai->pai_asid)) {
KASSERT(op == TLBINV_NOBODY);
} else {
pmap_tlb_pai_reset(ti, pai, pm);
}
}
#ifdef DIAGNOSTIC
size_t free_count __diagused = ti->ti_asid_max - pmap_tlb_asid_count(ti);
KASSERTMSG(free_count == ti->ti_asids_free,
"bitmap error: %zu != %u", free_count, ti->ti_asids_free);
#endif
UVMHIST_LOG(maphist, " <-- done", 0, 0, 0, 0);
}
#if defined(MULTIPROCESSOR) && defined(PMAP_TLB_NEED_SHOOTDOWN)
#if PMAP_TLB_MAX == 1
#error shootdown not required for single TLB systems
#endif
void
pmap_tlb_shootdown_process(void)
{
struct cpu_info * const ci = curcpu();
struct pmap_tlb_info * const ti = cpu_tlb_info(ci);
UVMHIST_FUNC(__func__);
UVMHIST_CALLED(maphist);
KASSERT(cpu_intr_p());
KASSERTMSG(ci->ci_cpl >= IPL_SCHED, "%s: cpl (%d) < IPL_SCHED (%d)",
__func__, ci->ci_cpl, IPL_SCHED);
TLBINFO_LOCK(ti);
UVMHIST_LOG(maphist, "ti %#jx", (uintptr_t)ti, 0, 0, 0);
switch (ti->ti_tlbinvop) {
case TLBINV_ONE: {
/*
* We only need to invalidate one user ASID.
*/
UVMHIST_LOG(maphist, "TLBINV_ONE ti->ti_victim %#jx", (uintptr_t)ti->ti_victim, 0, 0, 0);
struct pmap_asid_info * const pai = PMAP_PAI(ti->ti_victim, ti);
KASSERT(ti->ti_victim != pmap_kernel());
if (pmap_tlb_intersecting_onproc_p(ti->ti_victim, ti)) {
UVMHIST_LOG(maphist, "... onproc asid %jd", pai->pai_asid, 0, 0, 0);
/*
* The victim is an active pmap so we will just
* invalidate its TLB entries.
*/
KASSERT(pai->pai_asid > KERNEL_PID);
pmap_tlb_asid_check();
tlb_invalidate_asids(pai->pai_asid, pai->pai_asid);
pmap_tlb_asid_check();
} else if (pai->pai_asid) {
UVMHIST_LOG(maphist, "... not active asid %jd", pai->pai_asid, 0, 0, 0);
/*
* The victim is no longer an active pmap for this TLB.
* So simply clear its ASID and when pmap_activate is
* next called for this pmap, it will allocate a new
* ASID.
*/
pmap_tlb_pai_reset(ti, pai, PAI_PMAP(pai, ti));
}
break;
}
case TLBINV_ALLUSER:
/*
* Flush all user TLB entries.
*/
pmap_tlb_asid_reinitialize(ti, TLBINV_ALLUSER);
break;
case TLBINV_ALLKERNEL:
/*
* We need to invalidate all global TLB entries.
*/
pmap_tlb_asid_check();
tlb_invalidate_globals();
pmap_tlb_asid_check();
break;
case TLBINV_ALL:
/*
* Flush all the TLB entries (user and kernel).
*/
pmap_tlb_asid_reinitialize(ti, TLBINV_ALL);
break;
case TLBINV_NOBODY:
/*
* Might be spurious or another SMT CPU sharing this TLB
* could have already done the work.
*/
break;
}
/*
* Indicate we are done with shutdown event.
*/
ti->ti_victim = NULL;
ti->ti_tlbinvop = TLBINV_NOBODY;
TLBINFO_UNLOCK(ti);
}
/*
* This state machine could be encoded into an array of integers but since all
* the values fit in 3 bits, the 5 entry "table" fits in a 16 bit value which
* can be loaded in a single instruction.
*/
#define TLBINV_MAP(op, nobody, one, alluser, allkernel, all) \
(((( (nobody) << 3 * TLBINV_NOBODY) \
| ( (one) << 3 * TLBINV_ONE) \
| ( (alluser) << 3 * TLBINV_ALLUSER) \
| ((allkernel) << 3 * TLBINV_ALLKERNEL) \
| ( (all) << 3 * TLBINV_ALL)) >> 3 * (op)) & 7)
#define TLBINV_USER_MAP(op) \
TLBINV_MAP(op, TLBINV_ONE, TLBINV_ALLUSER, TLBINV_ALLUSER, \
TLBINV_ALL, TLBINV_ALL)
#define TLBINV_KERNEL_MAP(op) \
TLBINV_MAP(op, TLBINV_ALLKERNEL, TLBINV_ALL, TLBINV_ALL, \
TLBINV_ALLKERNEL, TLBINV_ALL)
bool
pmap_tlb_shootdown_bystanders(pmap_t pm)
{
/*
* We don't need to deal with our own TLB.
*/
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, "pm %#jx", (uintptr_t)pm, 0, 0, 0);
KASSERT(kpreempt_disabled());
const struct cpu_info * const ci = curcpu();
kcpuset_t *pm_active = ci->ci_shootdowncpus;
kcpuset_copy(pm_active, pm->pm_active);
kcpuset_remove(pm_active, cpu_tlb_info(curcpu())->ti_kcpuset);
const bool kernel_p = (pm == pmap_kernel());
bool ipi_sent = false;
/*
* If pm_active gets more bits set, then it's after all our changes
* have been made so they will already be cognizant of them.
*/
for (size_t i = 0; !kcpuset_iszero(pm_active); i++) {
KASSERT(i < pmap_ntlbs);
struct pmap_tlb_info * const ti = pmap_tlbs[i];
KASSERT(tlbinfo_index(ti) == i);
UVMHIST_LOG(maphist, "ti %#jx", (uintptr_t)ti, 0, 0, 0);
/*
* Skip this TLB if there are no active mappings for it.
*/
if (!kcpuset_intersecting_p(pm_active, ti->ti_kcpuset))
continue;
struct pmap_asid_info * const pai = PMAP_PAI(pm, ti);
kcpuset_remove(pm_active, ti->ti_kcpuset);
TLBINFO_LOCK(ti);
cpuid_t j = kcpuset_ffs_intersecting(pm->pm_onproc,
ti->ti_kcpuset);
// post decrement since ffs returns bit + 1 or 0 if no bit
if (j-- > 0) {
if (kernel_p) {
ti->ti_tlbinvop =
TLBINV_KERNEL_MAP(ti->ti_tlbinvop);
ti->ti_victim = NULL;
} else {
KASSERT(pai->pai_asid);
if (__predict_false(ti->ti_victim == pm)) {
KASSERT(ti->ti_tlbinvop == TLBINV_ONE);
/*
* We still need to invalidate this one
* ASID so there's nothing to change.
*/
} else {
ti->ti_tlbinvop =
TLBINV_USER_MAP(ti->ti_tlbinvop);
if (ti->ti_tlbinvop == TLBINV_ONE)
ti->ti_victim = pm;
else
ti->ti_victim = NULL;
}
}
UVMHIST_LOG(maphist, "tlbinvop %jx victim %#jx", ti->ti_tlbinvop,
(uintptr_t)ti->ti_victim, 0, 0);
TLBINFO_UNLOCK(ti);
/*
* Now we can send out the shootdown IPIs to a CPU
* that shares this TLB and is currently using this
* pmap. That CPU will process the IPI and do the
* all the work. Any other CPUs sharing that TLB
* will take advantage of that work. pm_onproc might
* change now that we have released the lock but we
* can tolerate spurious shootdowns.
*/
cpu_send_ipi(cpu_lookup(j), IPI_SHOOTDOWN);
ipi_sent = true;
continue;
}
if (!pmap_tlb_intersecting_active_p(pm, ti)) {
UVMHIST_LOG(maphist, "pm %#jx not active", (uintptr_t)pm, 0, 0, 0);
/*
* If this pmap has an ASID assigned but it's not
* currently running, nuke its ASID. Next time the
* pmap is activated, it will allocate a new ASID.
* And best of all, we avoid an IPI.
*/
KASSERT(!kernel_p);
pmap_tlb_pai_reset(ti, pai, pm);
//ti->ti_evcnt_lazy_shots.ev_count++;
}
TLBINFO_UNLOCK(ti);
}
UVMHIST_LOG(maphist, " <-- done (ipi_sent=%jd)", ipi_sent, 0, 0, 0);
return ipi_sent;
}
#endif /* MULTIPROCESSOR && PMAP_TLB_NEED_SHOOTDOWN */
int
pmap_tlb_update_addr(pmap_t pm, vaddr_t va, pt_entry_t pte, u_int flags)
{
KASSERT(kpreempt_disabled());
struct pmap_tlb_info * const ti = cpu_tlb_info(curcpu());
struct pmap_asid_info * const pai = PMAP_PAI(pm, ti);
int rv = -1;
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, " (pm=%#jx va=%#jx, pte=%#jx flags=%#jx)",
(uintptr_t)pm, va, pte_value(pte), flags);
KASSERTMSG(pte_valid_p(pte), "va %#"PRIxVADDR" %#"PRIxPTE,
va, pte_value(pte));
TLBINFO_LOCK(ti);
if (pm == pmap_kernel() || PMAP_PAI_ASIDVALID_P(pai, ti)) {
pmap_tlb_asid_check();
rv = tlb_update_addr(va, pai->pai_asid, pte,
(flags & PMAP_TLB_INSERT) != 0);
pmap_tlb_asid_check();
UVMHIST_LOG(maphist,
" %jd <-- tlb_update_addr(%#jx, %#jx, %#jx, ...)",
rv, va, pai->pai_asid, pte_value(pte));
KASSERTMSG((flags & PMAP_TLB_INSERT) == 0 || rv == 1,
"pmap %p (asid %u) va %#"PRIxVADDR" pte %#"PRIxPTE" rv %d",
pm, pai->pai_asid, va, pte_value(pte), rv);
}
#if defined(MULTIPROCESSOR) && defined(PMAP_TLB_NEED_SHOOTDOWN)
if (flags & PMAP_TLB_NEED_IPI)
pm->pm_shootdown_pending = 1;
#endif
TLBINFO_UNLOCK(ti);
UVMHIST_LOG(maphist, " <-- done (rv=%jd)", rv, 0, 0, 0);
return rv;
}
void
pmap_tlb_invalidate_addr(pmap_t pm, vaddr_t va)
{
KASSERT(kpreempt_disabled());
struct pmap_tlb_info * const ti = cpu_tlb_info(curcpu());
struct pmap_asid_info * const pai = PMAP_PAI(pm, ti);
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, " (pm=%#jx va=%#jx) ti=%#jx asid=%#jx",
(uintptr_t)pm, va, (uintptr_t)ti, pai->pai_asid);
TLBINFO_LOCK(ti);
if (pm == pmap_kernel() || PMAP_PAI_ASIDVALID_P(pai, ti)) {
pmap_tlb_asid_check();
UVMHIST_LOG(maphist, " invalidating %#jx asid %#jx",
va, pai->pai_asid, 0, 0);
tlb_invalidate_addr(va, pai->pai_asid);
pmap_tlb_asid_check();
}
#if defined(MULTIPROCESSOR) && defined(PMAP_TLB_NEED_SHOOTDOWN)
pm->pm_shootdown_pending = 1;
#endif
TLBINFO_UNLOCK(ti);
UVMHIST_LOG(maphist, " <-- done", 0, 0, 0, 0);
}
static inline void
pmap_tlb_asid_alloc(struct pmap_tlb_info *ti, pmap_t pm,
struct pmap_asid_info *pai)
{
/*
* We shouldn't have an ASID assigned, and thusly must not be onproc
* nor active.
*/
KASSERT(pm != pmap_kernel());
KASSERT(pai->pai_asid == 0);
KASSERT(pai->pai_link.le_prev == NULL);
#if defined(MULTIPROCESSOR)
KASSERT(!pmap_tlb_intersecting_onproc_p(pm, ti));
KASSERT(!pmap_tlb_intersecting_active_p(pm, ti));
#endif
KASSERT(ti->ti_asids_free > 0);
KASSERT(ti->ti_asid_hint > KERNEL_PID);
/*
* If the last ASID allocated was the maximum ASID, then the
* hint will be out of range. Reset the hint to first
* available ASID.
*/
if (PMAP_TLB_FLUSH_ASID_ON_RESET
&& ti->ti_asid_hint > ti->ti_asid_max) {
ti->ti_asid_hint = KERNEL_PID + 1;
}
KASSERTMSG(ti->ti_asid_hint <= ti->ti_asid_max, "hint %u",
ti->ti_asid_hint);
/*
* Let's see if the hinted ASID is free. If not search for
* a new one.
*/
if (__predict_true(TLBINFO_ASID_INUSE_P(ti, ti->ti_asid_hint))) {
const size_t nbpw = NBBY * sizeof(ti->ti_asid_bitmap._b[0]);
size_t i;
u_long bits;
for (i = 0; (bits = ~ti->ti_asid_bitmap._b[i]) == 0; i++) {
KASSERT(i < __arraycount(ti->ti_asid_bitmap._b) - 1);
}
/*
* ffs wants to find the first bit set while we want
* to find the first bit cleared.
*/
const u_int n = __builtin_ffsl(bits) - 1;
KASSERTMSG((bits << (nbpw - (n+1))) == (1ul << (nbpw-1)),
"n %u bits %#lx", n, bits);
KASSERT(n < nbpw);
ti->ti_asid_hint = n + i * nbpw;
}
KASSERT(ti->ti_asid_hint > KERNEL_PID);
KASSERT(ti->ti_asid_hint <= ti->ti_asid_max);
KASSERTMSG(PMAP_TLB_FLUSH_ASID_ON_RESET
|| TLBINFO_ASID_INUSE_P(ti, ti->ti_asid_hint - 1),
"hint %u bitmap %p", ti->ti_asid_hint, &ti->ti_asid_bitmap);
KASSERTMSG(!TLBINFO_ASID_INUSE_P(ti, ti->ti_asid_hint),
"hint %u bitmap %p", ti->ti_asid_hint, &ti->ti_asid_bitmap);
/*
* The hint contains our next ASID so take it and advance the hint.
* Mark it as used and insert the pai into the list of active asids.
* There is also one less asid free in this TLB.
*/
pai->pai_asid = ti->ti_asid_hint++;
#ifdef MULTIPROCESSOR
if (PMAP_TLB_FLUSH_ASID_ON_RESET) {
/*
* Clean the new ASID from the TLB.
*/
tlb_invalidate_asids(pai->pai_asid, pai->pai_asid);
}
#endif
TLBINFO_ASID_MARK_USED(ti, pai->pai_asid);
LIST_INSERT_HEAD(&ti->ti_pais, pai, pai_link);
ti->ti_asids_free--;
#if defined(MULTIPROCESSOR)
/*
* Mark that we now have an active ASID for all CPUs sharing this TLB.
* The bits in pm_active belonging to this TLB can only be changed
* while this TLBs lock is held.
*/
#if PMAP_TLB_MAX == 1
kcpuset_copy(pm->pm_active, kcpuset_running);
#else
kcpuset_merge(pm->pm_active, ti->ti_kcpuset);
#endif
#endif
}
/*
* Acquire a TLB address space tag (called ASID or TLBPID) and return it.
* ASID might have already been previously acquired.
*/
void
pmap_tlb_asid_acquire(pmap_t pm, struct lwp *l)
{
KASSERT(kpreempt_disabled());
struct cpu_info * const ci = l->l_cpu;
struct pmap_tlb_info * const ti = cpu_tlb_info(ci);
struct pmap_asid_info * const pai = PMAP_PAI(pm, ti);
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, "(pm=%#jx, l=%#jx, ti=%#jx)", (uintptr_t)pm,
(uintptr_t)l, (uintptr_t)ti, 0);
/*
* Kernels use a fixed ASID and thus doesn't need to acquire one.
*/
if (pm == pmap_kernel()) {
UVMHIST_LOG(maphist, " <-- done (kernel)", 0, 0, 0, 0);
return;
}
TLBINFO_LOCK(ti);
KASSERT(pai->pai_asid <= KERNEL_PID || pai->pai_link.le_prev != NULL);
KASSERT(pai->pai_asid > KERNEL_PID || pai->pai_link.le_prev == NULL);
pmap_tlb_pai_check(ti, true);
if (__predict_false(!tlbinfo_asids_p(ti))) {
#if defined(MULTIPROCESSOR)
/*
* Mark that we are active for all CPUs sharing this TLB.
* The bits in pm_active belonging to this TLB can only
* be changed while this TLBs lock is held.
*/
#if PMAP_TLB_MAX == 1
kcpuset_copy(pm->pm_active, kcpuset_running);
#else
kcpuset_merge(pm->pm_active, ti->ti_kcpuset);
#endif
#endif
} else if (__predict_false(!PMAP_PAI_ASIDVALID_P(pai, ti))) {
/*
* If we've run out ASIDs, reinitialize the ASID space.
*/
if (__predict_false(tlbinfo_noasids_p(ti))) {
KASSERT(l == curlwp);
UVMHIST_LOG(maphist, " asid reinit", 0, 0, 0, 0);
pmap_tlb_asid_reinitialize(ti, TLBINV_NOBODY);
KASSERT(!tlbinfo_noasids_p(ti));
}
/*
* Get an ASID.
*/
pmap_tlb_asid_alloc(ti, pm, pai);
UVMHIST_LOG(maphist, "allocated asid %#jx", pai->pai_asid,
0, 0, 0);
}
pmap_tlb_pai_check(ti, true);
#if defined(MULTIPROCESSOR)
KASSERT(kcpuset_isset(pm->pm_active, cpu_index(ci)));
#endif
if (l == curlwp) {
#if defined(MULTIPROCESSOR)
/*
* The bits in pm_onproc belonging to this TLB can only
* be changed while this TLBs lock is held unless atomic
* operations are used.
*/
KASSERT(pm != pmap_kernel());
kcpuset_atomic_set(pm->pm_onproc, cpu_index(ci));
#endif
ci->ci_pmap_asid_cur = pai->pai_asid;
UVMHIST_LOG(maphist, "setting asid to %#jx", pai->pai_asid,
0, 0, 0);
tlb_set_asid(pai->pai_asid, pm);
pmap_tlb_asid_check();
} else {
printf("%s: l (%p) != curlwp %p\n", __func__, l, curlwp);
}
TLBINFO_UNLOCK(ti);
UVMHIST_LOG(maphist, " <-- done", 0, 0, 0, 0);
}
void
pmap_tlb_asid_deactivate(pmap_t pm)
{
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, "pm %#jx", (uintptr_t)pm, 0, 0, 0);
KASSERT(kpreempt_disabled());
#if defined(MULTIPROCESSOR)
/*
* The kernel pmap is aways onproc and active and must never have
* those bits cleared. If pmap_remove_all was called, it has already
* deactivated the pmap and thusly onproc will be 0 so there's nothing
* to do.
*/
if (pm != pmap_kernel() && !kcpuset_iszero(pm->pm_onproc)) {
struct cpu_info * const ci = curcpu();
KASSERT(!cpu_intr_p());
KASSERTMSG(kcpuset_isset(pm->pm_onproc, cpu_index(ci)),
"%s: pmap %p onproc %p doesn't include cpu %d (%p)",
__func__, pm, pm->pm_onproc, cpu_index(ci), ci);
/*
* The bits in pm_onproc that belong to this TLB can
* be changed while this TLBs lock is not held as long
* as we use atomic ops.
*/
kcpuset_atomic_clear(pm->pm_onproc, cpu_index(ci));
}
#endif
curcpu()->ci_pmap_asid_cur = KERNEL_PID;
tlb_set_asid(KERNEL_PID, pmap_kernel());
pmap_tlb_pai_check(cpu_tlb_info(curcpu()), false);
#if defined(DEBUG)
pmap_tlb_asid_check();
#endif
UVMHIST_LOG(maphist, " <-- done (pm=%#jx)", (uintptr_t)pm, 0, 0, 0);
}
void
pmap_tlb_asid_release_all(struct pmap *pm)
{
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(maphist, "(pm=%#jx)", (uintptr_t)pm, 0, 0, 0);
KASSERT(pm != pmap_kernel());
#if defined(MULTIPROCESSOR)
//KASSERT(!kcpuset_iszero(pm->pm_onproc)); // XXX
struct cpu_info * const ci __diagused = curcpu();
KASSERT(!kcpuset_isotherset(pm->pm_onproc, cpu_index(ci)));
#if PMAP_TLB_MAX > 1
for (u_int i = 0; !kcpuset_iszero(pm->pm_active); i++) {
KASSERT(i < pmap_ntlbs);
struct pmap_tlb_info * const ti = pmap_tlbs[i];
#else
struct pmap_tlb_info * const ti = &pmap_tlb0_info;
#endif
struct pmap_asid_info * const pai = PMAP_PAI(pm, ti);
TLBINFO_LOCK(ti);
if (PMAP_PAI_ASIDVALID_P(pai, ti)) {
/*
* This pmap should not be in use by any other cpu so
* we can just reset and be happy.
*/
if (ti->ti_victim == pm)
ti->ti_victim = NULL;
if (__predict_true(tlbinfo_asids_p(ti)))
pmap_tlb_pai_reset(ti, pai, pm);
}
KASSERT(pai->pai_link.le_prev == NULL);
TLBINFO_UNLOCK(ti);
#if PMAP_TLB_MAX > 1
}
#endif
#ifdef DIAGNOSTIC
for (size_t i = 0; i < (PMAP_TLB_MAX > 1 ? pmap_ntlbs : 1); i++) {
KASSERTMSG(pm->pm_pai[i].pai_asid == 0,
"pm %p i %zu asid %u",
pm, i, pm->pm_pai[i].pai_asid);
}
#endif
#else
/*
* Handle the case of an UP kernel which only has, at most, one TLB.
* If the pmap has an ASID allocated, free it.
*/
struct pmap_tlb_info * const ti = &pmap_tlb0_info;
struct pmap_asid_info * const pai = PMAP_PAI(pm, ti);
TLBINFO_LOCK(ti);
if (pai->pai_asid > KERNEL_PID) {
if (curcpu()->ci_pmap_asid_cur == pai->pai_asid) {
tlb_invalidate_asids(pai->pai_asid, pai->pai_asid);
} else {
pmap_tlb_pai_reset(ti, pai, pm);
}
}
TLBINFO_UNLOCK(ti);
#endif /* MULTIPROCESSOR */
UVMHIST_LOG(maphist, " <-- done", 0, 0, 0, 0);
}
void
pmap_tlb_asid_check(void)
{
UVMHIST_FUNC(__func__);
UVMHIST_CALLED(maphist);
#ifdef DEBUG
kpreempt_disable();
const tlb_asid_t asid __debugused = tlb_get_asid();
UVMHIST_LOG(maphist, " asid %u vs pmap_cur_asid %u", asid,
curcpu()->ci_pmap_asid_cur, 0, 0);
KDASSERTMSG(asid == curcpu()->ci_pmap_asid_cur,
"%s: asid (%#x) != current asid (%#x)",
__func__, asid, curcpu()->ci_pmap_asid_cur);
kpreempt_enable();
#endif
UVMHIST_LOG(maphist, " <-- done", 0, 0, 0, 0);
}
#ifdef DEBUG
void
pmap_tlb_check(pmap_t pm, bool (*func)(void *, vaddr_t, tlb_asid_t, pt_entry_t))
{
struct pmap_tlb_info * const ti = cpu_tlb_info(curcpu());
struct pmap_asid_info * const pai = PMAP_PAI(pm, ti);
TLBINFO_LOCK(ti);
if (pm == pmap_kernel() || pai->pai_asid > KERNEL_PID)
tlb_walk(pm, func);
TLBINFO_UNLOCK(ti);
}
#endif /* DEBUG */
#ifdef DDB
void
pmap_db_tlb_print(struct pmap *pm,
void (*pr)(const char *, ...) __printflike(1, 2))
{
#if !defined(MULTIPROCESSOR) || PMAP_TLB_MAX == 1
pr(" asid %5u\n", pm->pm_pai[0].pai_asid);
#else
for (size_t i = 0; i < (PMAP_TLB_MAX > 1 ? pmap_ntlbs : 1); i++) {
pr(" tlb %zu asid %5u\n", i, pm->pm_pai[i].pai_asid);
}
#endif
}
#endif /* DDB */
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