freebsd-dev/sys/vm/vm_glue.c
Konstantin Belousov ed9e8bc468 Account the size of the vslock-ed memory by the thread.
Assert that all such memory is unwired on return to usermode.

The count of the wired memory will be used to detect the copyout mode.

Tested by:	pho (as part of the larger patch)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2018-03-24 13:51:27 +00:00

598 lines
15 KiB
C

/*-
* SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* 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.
*
* from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include "opt_kstack_pages.h"
#include "opt_kstack_max_pages.h"
#include "opt_kstack_usage_prof.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/sched.h>
#include <sys/sf_buf.h>
#include <sys/shm.h>
#include <sys/vmmeter.h>
#include <sys/vmem.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/_kstack_cache.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/unistd.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
#include <machine/cpu.h>
/*
* MPSAFE
*
* WARNING! This code calls vm_map_check_protection() which only checks
* the associated vm_map_entry range. It does not determine whether the
* contents of the memory is actually readable or writable. In most cases
* just checking the vm_map_entry is sufficient within the kernel's address
* space.
*/
int
kernacc(void *addr, int len, int rw)
{
boolean_t rv;
vm_offset_t saddr, eaddr;
vm_prot_t prot;
KASSERT((rw & ~VM_PROT_ALL) == 0,
("illegal ``rw'' argument to kernacc (%x)\n", rw));
if ((vm_offset_t)addr + len > kernel_map->max_offset ||
(vm_offset_t)addr + len < (vm_offset_t)addr)
return (FALSE);
prot = rw;
saddr = trunc_page((vm_offset_t)addr);
eaddr = round_page((vm_offset_t)addr + len);
vm_map_lock_read(kernel_map);
rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
vm_map_unlock_read(kernel_map);
return (rv == TRUE);
}
/*
* MPSAFE
*
* WARNING! This code calls vm_map_check_protection() which only checks
* the associated vm_map_entry range. It does not determine whether the
* contents of the memory is actually readable or writable. vmapbuf(),
* vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be
* used in conjunction with this call.
*/
int
useracc(void *addr, int len, int rw)
{
boolean_t rv;
vm_prot_t prot;
vm_map_t map;
KASSERT((rw & ~VM_PROT_ALL) == 0,
("illegal ``rw'' argument to useracc (%x)\n", rw));
prot = rw;
map = &curproc->p_vmspace->vm_map;
if ((vm_offset_t)addr + len > vm_map_max(map) ||
(vm_offset_t)addr + len < (vm_offset_t)addr) {
return (FALSE);
}
vm_map_lock_read(map);
rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr),
round_page((vm_offset_t)addr + len), prot);
vm_map_unlock_read(map);
return (rv == TRUE);
}
int
vslock(void *addr, size_t len)
{
vm_offset_t end, last, start;
vm_size_t npages;
int error;
last = (vm_offset_t)addr + len;
start = trunc_page((vm_offset_t)addr);
end = round_page(last);
if (last < (vm_offset_t)addr || end < (vm_offset_t)addr)
return (EINVAL);
npages = atop(end - start);
if (npages > vm_page_max_wired)
return (ENOMEM);
#if 0
/*
* XXX - not yet
*
* The limit for transient usage of wired pages should be
* larger than for "permanent" wired pages (mlock()).
*
* Also, the sysctl code, which is the only present user
* of vslock(), does a hard loop on EAGAIN.
*/
if (npages + vm_wire_count() > vm_page_max_wired)
return (EAGAIN);
#endif
error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end,
VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
if (error == KERN_SUCCESS) {
curthread->td_vslock_sz += len;
return (0);
}
/*
* Return EFAULT on error to match copy{in,out}() behaviour
* rather than returning ENOMEM like mlock() would.
*/
return (EFAULT);
}
void
vsunlock(void *addr, size_t len)
{
/* Rely on the parameter sanity checks performed by vslock(). */
MPASS(curthread->td_vslock_sz >= len);
curthread->td_vslock_sz -= len;
(void)vm_map_unwire(&curproc->p_vmspace->vm_map,
trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len),
VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
}
/*
* Pin the page contained within the given object at the given offset. If the
* page is not resident, allocate and load it using the given object's pager.
* Return the pinned page if successful; otherwise, return NULL.
*/
static vm_page_t
vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset)
{
vm_page_t m;
vm_pindex_t pindex;
int rv;
VM_OBJECT_WLOCK(object);
pindex = OFF_TO_IDX(offset);
m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
if (m->valid != VM_PAGE_BITS_ALL) {
vm_page_xbusy(m);
rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
if (rv != VM_PAGER_OK) {
vm_page_lock(m);
vm_page_free(m);
vm_page_unlock(m);
m = NULL;
goto out;
}
vm_page_xunbusy(m);
}
vm_page_lock(m);
vm_page_hold(m);
vm_page_activate(m);
vm_page_unlock(m);
out:
VM_OBJECT_WUNLOCK(object);
return (m);
}
/*
* Return a CPU private mapping to the page at the given offset within the
* given object. The page is pinned before it is mapped.
*/
struct sf_buf *
vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset)
{
vm_page_t m;
m = vm_imgact_hold_page(object, offset);
if (m == NULL)
return (NULL);
sched_pin();
return (sf_buf_alloc(m, SFB_CPUPRIVATE));
}
/*
* Destroy the given CPU private mapping and unpin the page that it mapped.
*/
void
vm_imgact_unmap_page(struct sf_buf *sf)
{
vm_page_t m;
m = sf_buf_page(sf);
sf_buf_free(sf);
sched_unpin();
vm_page_lock(m);
vm_page_unhold(m);
vm_page_unlock(m);
}
void
vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
{
pmap_sync_icache(map->pmap, va, sz);
}
struct kstack_cache_entry *kstack_cache;
static int kstack_cache_size = 128;
static int kstacks;
static struct mtx kstack_cache_mtx;
MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF);
SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0,
"");
SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0,
"");
/*
* Create the kernel stack (including pcb for i386) for a new thread.
* This routine directly affects the fork perf for a process and
* create performance for a thread.
*/
int
vm_thread_new(struct thread *td, int pages)
{
vm_object_t ksobj;
vm_offset_t ks;
vm_page_t ma[KSTACK_MAX_PAGES];
struct kstack_cache_entry *ks_ce;
int i;
/* Bounds check */
if (pages <= 1)
pages = kstack_pages;
else if (pages > KSTACK_MAX_PAGES)
pages = KSTACK_MAX_PAGES;
if (pages == kstack_pages) {
mtx_lock(&kstack_cache_mtx);
if (kstack_cache != NULL) {
ks_ce = kstack_cache;
kstack_cache = ks_ce->next_ks_entry;
mtx_unlock(&kstack_cache_mtx);
td->td_kstack_obj = ks_ce->ksobj;
td->td_kstack = (vm_offset_t)ks_ce;
td->td_kstack_pages = kstack_pages;
return (1);
}
mtx_unlock(&kstack_cache_mtx);
}
/*
* Allocate an object for the kstack.
*/
ksobj = vm_object_allocate(OBJT_DEFAULT, pages);
/*
* Get a kernel virtual address for this thread's kstack.
*/
#if defined(__mips__)
/*
* We need to align the kstack's mapped address to fit within
* a single TLB entry.
*/
if (vmem_xalloc(kernel_arena, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE,
PAGE_SIZE * 2, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
M_BESTFIT | M_NOWAIT, &ks)) {
ks = 0;
}
#else
ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
#endif
if (ks == 0) {
printf("vm_thread_new: kstack allocation failed\n");
vm_object_deallocate(ksobj);
return (0);
}
atomic_add_int(&kstacks, 1);
if (KSTACK_GUARD_PAGES != 0) {
pmap_qremove(ks, KSTACK_GUARD_PAGES);
ks += KSTACK_GUARD_PAGES * PAGE_SIZE;
}
td->td_kstack_obj = ksobj;
td->td_kstack = ks;
/*
* Knowing the number of pages allocated is useful when you
* want to deallocate them.
*/
td->td_kstack_pages = pages;
/*
* For the length of the stack, link in a real page of ram for each
* page of stack.
*/
VM_OBJECT_WLOCK(ksobj);
(void)vm_page_grab_pages(ksobj, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY |
VM_ALLOC_WIRED, ma, pages);
for (i = 0; i < pages; i++)
ma[i]->valid = VM_PAGE_BITS_ALL;
VM_OBJECT_WUNLOCK(ksobj);
pmap_qenter(ks, ma, pages);
return (1);
}
static void
vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages)
{
vm_page_t m;
int i;
atomic_add_int(&kstacks, -1);
pmap_qremove(ks, pages);
VM_OBJECT_WLOCK(ksobj);
for (i = 0; i < pages; i++) {
m = vm_page_lookup(ksobj, i);
if (m == NULL)
panic("vm_thread_dispose: kstack already missing?");
vm_page_lock(m);
vm_page_unwire(m, PQ_NONE);
vm_page_free(m);
vm_page_unlock(m);
}
VM_OBJECT_WUNLOCK(ksobj);
vm_object_deallocate(ksobj);
kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE),
(pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
}
/*
* Dispose of a thread's kernel stack.
*/
void
vm_thread_dispose(struct thread *td)
{
vm_object_t ksobj;
vm_offset_t ks;
struct kstack_cache_entry *ks_ce;
int pages;
pages = td->td_kstack_pages;
ksobj = td->td_kstack_obj;
ks = td->td_kstack;
td->td_kstack = 0;
td->td_kstack_pages = 0;
if (pages == kstack_pages && kstacks <= kstack_cache_size) {
ks_ce = (struct kstack_cache_entry *)ks;
ks_ce->ksobj = ksobj;
mtx_lock(&kstack_cache_mtx);
ks_ce->next_ks_entry = kstack_cache;
kstack_cache = ks_ce;
mtx_unlock(&kstack_cache_mtx);
return;
}
vm_thread_stack_dispose(ksobj, ks, pages);
}
static void
vm_thread_stack_lowmem(void *nulll)
{
struct kstack_cache_entry *ks_ce, *ks_ce1;
mtx_lock(&kstack_cache_mtx);
ks_ce = kstack_cache;
kstack_cache = NULL;
mtx_unlock(&kstack_cache_mtx);
while (ks_ce != NULL) {
ks_ce1 = ks_ce;
ks_ce = ks_ce->next_ks_entry;
vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1,
kstack_pages);
}
}
static void
kstack_cache_init(void *nulll)
{
EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL,
EVENTHANDLER_PRI_ANY);
}
SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL);
#ifdef KSTACK_USAGE_PROF
/*
* Track maximum stack used by a thread in kernel.
*/
static int max_kstack_used;
SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD,
&max_kstack_used, 0,
"Maxiumum stack depth used by a thread in kernel");
void
intr_prof_stack_use(struct thread *td, struct trapframe *frame)
{
vm_offset_t stack_top;
vm_offset_t current;
int used, prev_used;
/*
* Testing for interrupted kernel mode isn't strictly
* needed. It optimizes the execution, since interrupts from
* usermode will have only the trap frame on the stack.
*/
if (TRAPF_USERMODE(frame))
return;
stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
current = (vm_offset_t)(uintptr_t)&stack_top;
/*
* Try to detect if interrupt is using kernel thread stack.
* Hardware could use a dedicated stack for interrupt handling.
*/
if (stack_top <= current || current < td->td_kstack)
return;
used = stack_top - current;
for (;;) {
prev_used = max_kstack_used;
if (prev_used >= used)
break;
if (atomic_cmpset_int(&max_kstack_used, prev_used, used))
break;
}
}
#endif /* KSTACK_USAGE_PROF */
/*
* Implement fork's actions on an address space.
* Here we arrange for the address space to be copied or referenced,
* allocate a user struct (pcb and kernel stack), then call the
* machine-dependent layer to fill those in and make the new process
* ready to run. The new process is set up so that it returns directly
* to user mode to avoid stack copying and relocation problems.
*/
int
vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2,
struct vmspace *vm2, int flags)
{
struct proc *p1 = td->td_proc;
int error;
if ((flags & RFPROC) == 0) {
/*
* Divorce the memory, if it is shared, essentially
* this changes shared memory amongst threads, into
* COW locally.
*/
if ((flags & RFMEM) == 0) {
if (p1->p_vmspace->vm_refcnt > 1) {
error = vmspace_unshare(p1);
if (error)
return (error);
}
}
cpu_fork(td, p2, td2, flags);
return (0);
}
if (flags & RFMEM) {
p2->p_vmspace = p1->p_vmspace;
atomic_add_int(&p1->p_vmspace->vm_refcnt, 1);
}
while (vm_page_count_severe()) {
vm_wait_severe();
}
if ((flags & RFMEM) == 0) {
p2->p_vmspace = vm2;
if (p1->p_vmspace->vm_shm)
shmfork(p1, p2);
}
/*
* cpu_fork will copy and update the pcb, set up the kernel stack,
* and make the child ready to run.
*/
cpu_fork(td, p2, td2, flags);
return (0);
}
/*
* Called after process has been wait(2)'ed upon and is being reaped.
* The idea is to reclaim resources that we could not reclaim while
* the process was still executing.
*/
void
vm_waitproc(p)
struct proc *p;
{
vmspace_exitfree(p); /* and clean-out the vmspace */
}
void
kick_proc0(void)
{
wakeup(&proc0);
}