/*- * 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 __FBSDID("$FreeBSD$"); #include "opt_vm.h" #include "opt_kstack_pages.h" #include "opt_kstack_max_pages.h" #include "opt_kstack_usage_prof.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * 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 > vm_map_max(kernel_map) || (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_user_wired) return (ENOMEM); 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 | VM_ALLOC_WIRED); 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_unwire(m, PQ_NONE); vm_page_free(m); vm_page_unlock(m); m = NULL; goto out; } vm_page_xunbusy(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_unwire(m, PQ_ACTIVE); 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); } static uma_zone_t kstack_cache; static int kstack_cache_size = 128; static int kstack_domain_iter; static int sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS) { int error, newsize; newsize = kstack_cache_size; error = sysctl_handle_int(oidp, &newsize, 0, req); if (error == 0 && req->newptr && newsize != kstack_cache_size) kstack_cache_size = uma_zone_set_maxcache(kstack_cache, newsize); return (error); } SYSCTL_PROC(_vm, OID_AUTO, kstack_cache_size, CTLTYPE_INT|CTLFLAG_RW, &kstack_cache_size, 0, sysctl_kstack_cache_size, "IU", "Maximum number of cached kernel stacks"); /* * 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. */ static vm_offset_t vm_thread_stack_create(struct domainset *ds, vm_object_t *ksobjp, int pages) { vm_page_t ma[KSTACK_MAX_PAGES]; vm_object_t ksobj; vm_offset_t ks; int i; /* * 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); } if (vm_ndomains > 1) { ksobj->domain.dr_policy = ds; ksobj->domain.dr_iter = atomic_fetchadd_int(&kstack_domain_iter, 1); } if (KSTACK_GUARD_PAGES != 0) { pmap_qremove(ks, KSTACK_GUARD_PAGES); ks += KSTACK_GUARD_PAGES * PAGE_SIZE; } /* * 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); *ksobjp = ksobj; return (ks); } static void vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages) { vm_page_t m; int i; 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_noq(m); 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); } /* * Allocate the kernel stack for a new thread. */ int vm_thread_new(struct thread *td, int pages) { vm_object_t ksobj; vm_offset_t ks; /* Bounds check */ if (pages <= 1) pages = kstack_pages; else if (pages > KSTACK_MAX_PAGES) pages = KSTACK_MAX_PAGES; ks = 0; ksobj = NULL; if (pages == kstack_pages && kstack_cache != NULL) { ks = (vm_offset_t)uma_zalloc(kstack_cache, M_NOWAIT); if (ks != 0) ksobj = PHYS_TO_VM_PAGE(pmap_kextract(ks))->object; } /* * Ensure that kstack objects can draw pages from any memory * domain. Otherwise a local memory shortage can block a process * swap-in. */ if (ks == 0) ks = vm_thread_stack_create(DOMAINSET_PREF(PCPU_GET(domain)), &ksobj, pages); if (ks == 0) return (0); td->td_kstack_obj = ksobj; td->td_kstack = ks; td->td_kstack_pages = pages; return (1); } /* * Dispose of a thread's kernel stack. */ void vm_thread_dispose(struct thread *td) { vm_object_t ksobj; vm_offset_t ks; 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) uma_zfree(kstack_cache, (void *)ks); else vm_thread_stack_dispose(ksobj, ks, pages); } static int kstack_import(void *arg, void **store, int cnt, int domain, int flags) { struct domainset *ds; vm_object_t ksobj; int i; if (domain == UMA_ANYDOMAIN) ds = DOMAINSET_RR(); else ds = DOMAINSET_PREF(domain); for (i = 0; i < cnt; i++) { store[i] = (void *)vm_thread_stack_create(ds, &ksobj, kstack_pages); if (store[i] == NULL) break; } return (i); } static void kstack_release(void *arg, void **store, int cnt) { vm_offset_t ks; int i; for (i = 0; i < cnt; i++) { ks = (vm_offset_t)store[i]; vm_thread_stack_dispose( PHYS_TO_VM_PAGE(pmap_kextract(ks))->object, ks, kstack_pages); } } static void kstack_cache_init(void *null) { kstack_cache = uma_zcache_create("kstack_cache", kstack_pages * PAGE_SIZE, NULL, NULL, NULL, NULL, kstack_import, kstack_release, NULL, UMA_ZONE_NUMA|UMA_ZONE_MINBUCKET); uma_zone_set_maxcache(kstack_cache, kstack_cache_size); } 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; struct domainset *dset; 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); } dset = td2->td_domain.dr_policy; while (vm_page_count_severe_set(&dset->ds_mask)) { vm_wait_doms(&dset->ds_mask); } 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); }