/* $OpenBSD: uvm_mmap.c,v 1.93 2013/05/30 16:29:46 tedu Exp $ */ /* $NetBSD: uvm_mmap.c,v 1.49 2001/02/18 21:19:08 chs Exp $ */ /* * Copyright (c) 1997 Charles D. Cranor and Washington University. * Copyright (c) 1991, 1993 The Regents of the University of California. * Copyright (c) 1988 University of Utah. * * All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department. * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the Charles D. Cranor, * Washington University, University of California, Berkeley and * its contributors. * 4. 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: Utah $Hdr: vm_mmap.c 1.6 91/10/21$ * @(#)vm_mmap.c 8.5 (Berkeley) 5/19/94 * from: Id: uvm_mmap.c,v 1.1.2.14 1998/01/05 21:04:26 chuck Exp */ /* * uvm_mmap.c: system call interface into VM system, plus kernel vm_mmap * function. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for __LDPGSZ */ #include #include #include #include /* * Page align addr and size, returning EINVAL on wraparound. */ #define ALIGN_ADDR(addr, size, pageoff) do { \ pageoff = (addr & PAGE_MASK); \ if (pageoff != 0) { \ if (size > SIZE_MAX - pageoff) \ return (EINVAL); /* wraparound */ \ addr -= pageoff; \ size += pageoff; \ } \ if (size != 0) { \ size = (vsize_t)round_page(size); \ if (size == 0) \ return (EINVAL); /* wraparound */ \ } \ } while (0) /* * sys_mquery: provide mapping hints to applications that do fixed mappings * * flags: 0 or MAP_FIXED (MAP_FIXED - means that we insist on this addr and * don't care about PMAP_PREFER or such) * addr: hint where we'd like to place the mapping. * size: size of the mapping * fd: fd of the file we want to map * off: offset within the file */ int sys_mquery(struct proc *p, void *v, register_t *retval) { struct sys_mquery_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(int) prot; syscallarg(int) flags; syscallarg(int) fd; syscallarg(long) pad; syscallarg(off_t) pos; } */ *uap = v; struct file *fp; struct uvm_object *uobj; voff_t uoff; int error; vaddr_t vaddr; int flags = 0; vsize_t size; vm_prot_t prot; int fd; vaddr = (vaddr_t) SCARG(uap, addr); prot = SCARG(uap, prot); size = (vsize_t) SCARG(uap, len); fd = SCARG(uap, fd); if ((prot & VM_PROT_ALL) != prot) return (EINVAL); if (SCARG(uap, flags) & MAP_FIXED) flags |= UVM_FLAG_FIXED; if (fd >= 0) { if ((error = getvnode(p->p_fd, fd, &fp)) != 0) return (error); uobj = &((struct vnode *)fp->f_data)->v_uvm.u_obj; uoff = SCARG(uap, pos); } else { fp = NULL; uobj = NULL; uoff = UVM_UNKNOWN_OFFSET; } if (vaddr == 0) vaddr = uvm_map_hint(p->p_vmspace, prot); error = uvm_map_mquery(&p->p_vmspace->vm_map, &vaddr, size, uoff, flags); if (error == 0) *retval = (register_t)(vaddr); if (fp != NULL) FRELE(fp, p); return (error); } /* * sys_mincore: determine if pages are in core or not. */ /* ARGSUSED */ int sys_mincore(struct proc *p, void *v, register_t *retval) { struct sys_mincore_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(char *) vec; } */ *uap = v; vm_page_t m; char *vec, *pgi, *pgs; struct uvm_object *uobj; struct vm_amap *amap; struct vm_anon *anon; vm_map_entry_t entry, next; vaddr_t start, end, lim; vm_map_t map; vsize_t len, npgs; int error = 0; map = &p->p_vmspace->vm_map; start = (vaddr_t)SCARG(uap, addr); len = SCARG(uap, len); vec = SCARG(uap, vec); if (start & PAGE_MASK) return (EINVAL); len = round_page(len); end = start + len; if (end <= start) return (EINVAL); npgs = len >> PAGE_SHIFT; /* * < art> Anyone trying to mincore more than 4GB of address space is * clearly insane. */ if (npgs >= (0xffffffff >> PAGE_SHIFT)) return (E2BIG); pgs = malloc(sizeof(*pgs) * npgs, M_TEMP, M_WAITOK | M_CANFAIL); if (pgs == NULL) return (ENOMEM); pgi = pgs; /* * Lock down vec, so our returned status isn't outdated by * storing the status byte for a page. */ if ((error = uvm_vslock(p, vec, npgs, VM_PROT_WRITE)) != 0) { free(pgs, M_TEMP); return (error); } vm_map_lock_read(map); if (uvm_map_lookup_entry(map, start, &entry) == FALSE) { error = ENOMEM; goto out; } for (/* nothing */; entry != NULL && entry->start < end; entry = RB_NEXT(uvm_map_addr, &map->addr, entry)) { KASSERT(!UVM_ET_ISSUBMAP(entry)); KASSERT(start >= entry->start); /* Make sure there are no holes. */ next = RB_NEXT(uvm_map_addr, &map->addr, entry); if (entry->end < end && (next == NULL || next->start > entry->end)) { error = ENOMEM; goto out; } lim = end < entry->end ? end : entry->end; /* * Special case for objects with no "real" pages. Those * are always considered resident (mapped devices). */ if (UVM_ET_ISOBJ(entry)) { KASSERT(!UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj)); if (entry->object.uvm_obj->pgops->pgo_fault != NULL) { for (/* nothing */; start < lim; start += PAGE_SIZE, pgi++) *pgi = 1; continue; } } amap = entry->aref.ar_amap; /* top layer */ uobj = entry->object.uvm_obj; /* bottom layer */ for (/* nothing */; start < lim; start += PAGE_SIZE, pgi++) { *pgi = 0; if (amap != NULL) { /* Check the top layer first. */ anon = amap_lookup(&entry->aref, start - entry->start); if (anon != NULL && anon->an_page != NULL) { /* * Anon has the page for this entry * offset. */ *pgi = 1; } } if (uobj != NULL && *pgi == 0) { /* Check the bottom layer. */ m = uvm_pagelookup(uobj, entry->offset + (start - entry->start)); if (m != NULL) { /* * Object has the page for this entry * offset. */ *pgi = 1; } } } } out: vm_map_unlock_read(map); uvm_vsunlock(p, SCARG(uap, vec), npgs); /* now the map is unlocked we can copyout without fear. */ if (error == 0) copyout(pgs, vec, npgs * sizeof(char)); free(pgs, M_TEMP); return (error); } /* * sys_mmap: mmap system call. * * => file offset and address may not be page aligned * - if MAP_FIXED, offset and address must have remainder mod PAGE_SIZE * - if address isn't page aligned the mapping starts at trunc_page(addr) * and the return value is adjusted up by the page offset. */ int sys_mmap(struct proc *p, void *v, register_t *retval) { struct sys_mmap_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(int) prot; syscallarg(int) flags; syscallarg(int) fd; syscallarg(long) pad; syscallarg(off_t) pos; } */ *uap = v; vaddr_t addr; struct vattr va; off_t pos; vsize_t size, pageoff; vm_prot_t prot, maxprot; int flags, fd; vaddr_t vm_min_address = VM_MIN_ADDRESS; struct filedesc *fdp = p->p_fd; struct file *fp = NULL; struct vnode *vp; caddr_t handle; int error; /* * first, extract syscall args from the uap. */ addr = (vaddr_t) SCARG(uap, addr); size = (vsize_t) SCARG(uap, len); prot = SCARG(uap, prot); flags = SCARG(uap, flags); fd = SCARG(uap, fd); pos = SCARG(uap, pos); /* * Fixup the old deprecated MAP_COPY into MAP_PRIVATE, and * validate the flags. */ if ((prot & VM_PROT_ALL) != prot) return (EINVAL); if ((flags & MAP_FLAGMASK) != flags) return (EINVAL); if (flags & MAP_COPY) flags = (flags & ~MAP_COPY) | MAP_PRIVATE; if ((flags & (MAP_SHARED|MAP_PRIVATE)) == (MAP_SHARED|MAP_PRIVATE)) return (EINVAL); if ((flags & (MAP_FIXED|__MAP_NOREPLACE)) == __MAP_NOREPLACE) return (EINVAL); if (size == 0) return (EINVAL); /* * align file position and save offset. adjust size. */ ALIGN_ADDR(pos, size, pageoff); /* * now check (MAP_FIXED) or get (!MAP_FIXED) the "addr" */ if (flags & MAP_FIXED) { /* adjust address by the same amount as we did the offset */ addr -= pageoff; if (addr & PAGE_MASK) return (EINVAL); /* not page aligned */ if (addr > SIZE_MAX - size) return (EINVAL); /* no wrapping! */ if (VM_MAXUSER_ADDRESS > 0 && (addr + size) > VM_MAXUSER_ADDRESS) return (EINVAL); if (vm_min_address > 0 && addr < vm_min_address) return (EINVAL); } /* * check for file mappings (i.e. not anonymous) and verify file. */ if ((flags & MAP_ANON) == 0) { if ((fp = fd_getfile(fdp, fd)) == NULL) return (EBADF); FREF(fp); if (fp->f_type != DTYPE_VNODE) { error = ENODEV; /* only mmap vnodes! */ goto out; } vp = (struct vnode *)fp->f_data; /* convert to vnode */ if (vp->v_type != VREG && vp->v_type != VCHR && vp->v_type != VBLK) { error = ENODEV; /* only REG/CHR/BLK support mmap */ goto out; } if (vp->v_type == VREG && (pos + size) < pos) { error = EINVAL; /* no offset wrapping */ goto out; } /* special case: catch SunOS style /dev/zero */ if (vp->v_type == VCHR && iszerodev(vp->v_rdev)) { flags |= MAP_ANON; FRELE(fp, p); fp = NULL; goto is_anon; } /* * Old programs may not select a specific sharing type, so * default to an appropriate one. * * XXX: how does MAP_ANON fit in the picture? */ if ((flags & (MAP_SHARED|MAP_PRIVATE)) == 0) { #if defined(DEBUG) printf("WARNING: defaulted mmap() share type to " "%s (pid %d comm %s)\n", vp->v_type == VCHR ? "MAP_SHARED" : "MAP_PRIVATE", p->p_pid, p->p_comm); #endif if (vp->v_type == VCHR) flags |= MAP_SHARED; /* for a device */ else flags |= MAP_PRIVATE; /* for a file */ } /* * MAP_PRIVATE device mappings don't make sense (and aren't * supported anyway). However, some programs rely on this, * so just change it to MAP_SHARED. */ if (vp->v_type == VCHR && (flags & MAP_PRIVATE) != 0) { flags = (flags & ~MAP_PRIVATE) | MAP_SHARED; } /* * now check protection */ maxprot = VM_PROT_EXECUTE; /* check read access */ if (fp->f_flag & FREAD) maxprot |= VM_PROT_READ; else if (prot & PROT_READ) { error = EACCES; goto out; } /* check write access, shared case first */ if (flags & MAP_SHARED) { /* * if the file is writable, only add PROT_WRITE to * maxprot if the file is not immutable, append-only. * otherwise, if we have asked for PROT_WRITE, return * EPERM. */ if (fp->f_flag & FWRITE) { if ((error = VOP_GETATTR(vp, &va, p->p_ucred, p))) goto out; if ((va.va_flags & (IMMUTABLE|APPEND)) == 0) maxprot |= VM_PROT_WRITE; else if (prot & PROT_WRITE) { error = EPERM; goto out; } } else if (prot & PROT_WRITE) { error = EACCES; goto out; } } else { /* MAP_PRIVATE mappings can always write to */ maxprot |= VM_PROT_WRITE; } /* * set handle to vnode */ handle = (caddr_t)vp; } else { /* MAP_ANON case */ /* * XXX What do we do about (MAP_SHARED|MAP_PRIVATE) == 0? */ if (fd != -1) { error = EINVAL; goto out; } is_anon: /* label for SunOS style /dev/zero */ handle = NULL; maxprot = VM_PROT_ALL; pos = 0; } if ((flags & MAP_ANON) != 0 || ((flags & MAP_PRIVATE) != 0 && (prot & PROT_WRITE) != 0)) { if (size > (p->p_rlimit[RLIMIT_DATA].rlim_cur - ptoa(p->p_vmspace->vm_dused))) { error = ENOMEM; goto out; } } /* * now let kernel internal function uvm_mmap do the work. */ error = uvm_mmap(&p->p_vmspace->vm_map, &addr, size, prot, maxprot, flags, handle, pos, p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur, p); if (error == 0) /* remember to add offset */ *retval = (register_t)(addr + pageoff); out: if (fp) FRELE(fp, p); return (error); } /* * sys_msync: the msync system call (a front-end for flush) */ int sys_msync(struct proc *p, void *v, register_t *retval) { struct sys_msync_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(int) flags; } */ *uap = v; vaddr_t addr; vsize_t size, pageoff; vm_map_t map; int flags, uvmflags; /* * extract syscall args from the uap */ addr = (vaddr_t)SCARG(uap, addr); size = (vsize_t)SCARG(uap, len); flags = SCARG(uap, flags); /* sanity check flags */ if ((flags & ~(MS_ASYNC | MS_SYNC | MS_INVALIDATE)) != 0 || (flags & (MS_ASYNC | MS_SYNC | MS_INVALIDATE)) == 0 || (flags & (MS_ASYNC | MS_SYNC)) == (MS_ASYNC | MS_SYNC)) return (EINVAL); if ((flags & (MS_ASYNC | MS_SYNC)) == 0) flags |= MS_SYNC; /* * align the address to a page boundary, and adjust the size accordingly */ ALIGN_ADDR(addr, size, pageoff); if (addr > SIZE_MAX - size) return (EINVAL); /* disallow wrap-around. */ /* * get map */ map = &p->p_vmspace->vm_map; /* * translate MS_ flags into PGO_ flags */ uvmflags = PGO_CLEANIT; if (flags & MS_INVALIDATE) uvmflags |= PGO_FREE; if (flags & MS_SYNC) uvmflags |= PGO_SYNCIO; else uvmflags |= PGO_SYNCIO; /* XXXCDC: force sync for now! */ return (uvm_map_clean(map, addr, addr+size, uvmflags)); } /* * sys_munmap: unmap a users memory */ int sys_munmap(struct proc *p, void *v, register_t *retval) { struct sys_munmap_args /* { syscallarg(void *) addr; syscallarg(size_t) len; } */ *uap = v; vaddr_t addr; vsize_t size, pageoff; vm_map_t map; vaddr_t vm_min_address = VM_MIN_ADDRESS; struct uvm_map_deadq dead_entries; /* * get syscall args... */ addr = (vaddr_t) SCARG(uap, addr); size = (vsize_t) SCARG(uap, len); /* * align the address to a page boundary, and adjust the size accordingly */ ALIGN_ADDR(addr, size, pageoff); /* * Check for illegal addresses. Watch out for address wrap... * Note that VM_*_ADDRESS are not constants due to casts (argh). */ if (addr > SIZE_MAX - size) return (EINVAL); if (VM_MAXUSER_ADDRESS > 0 && addr + size > VM_MAXUSER_ADDRESS) return (EINVAL); if (vm_min_address > 0 && addr < vm_min_address) return (EINVAL); map = &p->p_vmspace->vm_map; vm_map_lock(map); /* lock map so we can checkprot */ /* * interesting system call semantic: make sure entire range is * allocated before allowing an unmap. */ if (!uvm_map_checkprot(map, addr, addr + size, VM_PROT_NONE)) { vm_map_unlock(map); return (EINVAL); } /* * doit! */ TAILQ_INIT(&dead_entries); uvm_unmap_remove(map, addr, addr + size, &dead_entries, FALSE, TRUE); vm_map_unlock(map); /* and unlock */ uvm_unmap_detach(&dead_entries, 0); return (0); } /* * sys_mprotect: the mprotect system call */ int sys_mprotect(struct proc *p, void *v, register_t *retval) { struct sys_mprotect_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(int) prot; } */ *uap = v; vaddr_t addr; vsize_t size, pageoff; vm_prot_t prot; /* * extract syscall args from uap */ addr = (vaddr_t)SCARG(uap, addr); size = (vsize_t)SCARG(uap, len); prot = SCARG(uap, prot); if ((prot & VM_PROT_ALL) != prot) return (EINVAL); /* * align the address to a page boundary, and adjust the size accordingly */ ALIGN_ADDR(addr, size, pageoff); if (addr > SIZE_MAX - size) return (EINVAL); /* disallow wrap-around. */ return (uvm_map_protect(&p->p_vmspace->vm_map, addr, addr+size, prot, FALSE)); } /* * sys_minherit: the minherit system call */ int sys_minherit(struct proc *p, void *v, register_t *retval) { struct sys_minherit_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(int) inherit; } */ *uap = v; vaddr_t addr; vsize_t size, pageoff; vm_inherit_t inherit; addr = (vaddr_t)SCARG(uap, addr); size = (vsize_t)SCARG(uap, len); inherit = SCARG(uap, inherit); /* * align the address to a page boundary, and adjust the size accordingly */ ALIGN_ADDR(addr, size, pageoff); if (addr > SIZE_MAX - size) return (EINVAL); /* disallow wrap-around. */ return (uvm_map_inherit(&p->p_vmspace->vm_map, addr, addr+size, inherit)); } /* * sys_madvise: give advice about memory usage. */ /* ARGSUSED */ int sys_madvise(struct proc *p, void *v, register_t *retval) { struct sys_madvise_args /* { syscallarg(void *) addr; syscallarg(size_t) len; syscallarg(int) behav; } */ *uap = v; vaddr_t addr; vsize_t size, pageoff; int advice, error; addr = (vaddr_t)SCARG(uap, addr); size = (vsize_t)SCARG(uap, len); advice = SCARG(uap, behav); /* * align the address to a page boundary, and adjust the size accordingly */ ALIGN_ADDR(addr, size, pageoff); if (addr > SIZE_MAX - size) return (EINVAL); /* disallow wrap-around. */ switch (advice) { case MADV_NORMAL: case MADV_RANDOM: case MADV_SEQUENTIAL: error = uvm_map_advice(&p->p_vmspace->vm_map, addr, addr + size, advice); break; case MADV_WILLNEED: /* * Activate all these pages, pre-faulting them in if * necessary. */ /* * XXX IMPLEMENT ME. * Should invent a "weak" mode for uvm_fault() * which would only do the PGO_LOCKED pgo_get(). */ return (0); case MADV_DONTNEED: /* * Deactivate all these pages. We don't need them * any more. We don't, however, toss the data in * the pages. */ error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size, PGO_DEACTIVATE); break; case MADV_FREE: /* * These pages contain no valid data, and may be * garbage-collected. Toss all resources, including * any swap space in use. */ error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size, PGO_FREE); break; case MADV_SPACEAVAIL: /* * XXXMRG What is this? I think it's: * * Ensure that we have allocated backing-store * for these pages. * * This is going to require changes to the page daemon, * as it will free swap space allocated to pages in core. * There's also what to do for device/file/anonymous memory. */ return (EINVAL); default: return (EINVAL); } return (error); } /* * sys_mlock: memory lock */ int sys_mlock(struct proc *p, void *v, register_t *retval) { struct sys_mlock_args /* { syscallarg(const void *) addr; syscallarg(size_t) len; } */ *uap = v; vaddr_t addr; vsize_t size, pageoff; int error; /* * extract syscall args from uap */ addr = (vaddr_t)SCARG(uap, addr); size = (vsize_t)SCARG(uap, len); /* * align the address to a page boundary and adjust the size accordingly */ ALIGN_ADDR(addr, size, pageoff); if (addr > SIZE_MAX - size) return (EINVAL); /* disallow wrap-around. */ if (atop(size) + uvmexp.wired > uvmexp.wiredmax) return (EAGAIN); #ifdef pmap_wired_count if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) > p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur) return (EAGAIN); #else if ((error = suser(p, 0)) != 0) return (error); #endif error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, FALSE, 0); return (error == 0 ? 0 : ENOMEM); } /* * sys_munlock: unlock wired pages */ int sys_munlock(struct proc *p, void *v, register_t *retval) { struct sys_munlock_args /* { syscallarg(const void *) addr; syscallarg(size_t) len; } */ *uap = v; vaddr_t addr; vsize_t size, pageoff; int error; /* * extract syscall args from uap */ addr = (vaddr_t)SCARG(uap, addr); size = (vsize_t)SCARG(uap, len); /* * align the address to a page boundary, and adjust the size accordingly */ ALIGN_ADDR(addr, size, pageoff); if (addr > SIZE_MAX - size) return (EINVAL); /* disallow wrap-around. */ #ifndef pmap_wired_count if ((error = suser(p, 0)) != 0) return (error); #endif error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, TRUE, 0); return (error == 0 ? 0 : ENOMEM); } /* * sys_mlockall: lock all pages mapped into an address space. */ int sys_mlockall(struct proc *p, void *v, register_t *retval) { struct sys_mlockall_args /* { syscallarg(int) flags; } */ *uap = v; int error, flags; flags = SCARG(uap, flags); if (flags == 0 || (flags & ~(MCL_CURRENT|MCL_FUTURE)) != 0) return (EINVAL); #ifndef pmap_wired_count if ((error = suser(p, 0)) != 0) return (error); #endif error = uvm_map_pageable_all(&p->p_vmspace->vm_map, flags, p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur); if (error != 0 && error != ENOMEM) return (EAGAIN); return (error); } /* * sys_munlockall: unlock all pages mapped into an address space. */ int sys_munlockall(struct proc *p, void *v, register_t *retval) { (void) uvm_map_pageable_all(&p->p_vmspace->vm_map, 0, 0); return (0); } /* * uvm_mmap: internal version of mmap * * - used by sys_mmap, exec, and sysv shm * - handle is a vnode pointer or NULL for MAP_ANON (XXX: not true, * sysv shm uses "named anonymous memory") * - caller must page-align the file offset */ int uvm_mmap(vm_map_t map, vaddr_t *addr, vsize_t size, vm_prot_t prot, vm_prot_t maxprot, int flags, caddr_t handle, voff_t foff, vsize_t locklimit, struct proc *p) { struct uvm_object *uobj; struct vnode *vp; int error; int advice = UVM_ADV_NORMAL; uvm_flag_t uvmflag = 0; vsize_t align = 0; /* userland page size */ /* * check params */ if (size == 0) return(0); if (foff & PAGE_MASK) return(EINVAL); if ((prot & maxprot) != prot) return(EINVAL); /* * for non-fixed mappings, round off the suggested address. * for fixed mappings, check alignment and zap old mappings. */ if ((flags & MAP_FIXED) == 0) { *addr = round_page(*addr); /* round */ } else { if (*addr & PAGE_MASK) return(EINVAL); uvmflag |= UVM_FLAG_FIXED; if ((flags & __MAP_NOREPLACE) == 0) uvm_unmap(map, *addr, *addr + size); /* zap! */ } /* * handle anon vs. non-anon mappings. for non-anon mappings attach * to underlying vm object. */ if (flags & MAP_ANON) { if ((flags & MAP_FIXED) == 0 && size >= __LDPGSZ) align = __LDPGSZ; foff = UVM_UNKNOWN_OFFSET; uobj = NULL; if ((flags & MAP_SHARED) == 0) /* XXX: defer amap create */ uvmflag |= UVM_FLAG_COPYONW; else /* shared: create amap now */ uvmflag |= UVM_FLAG_OVERLAY; } else { vp = (struct vnode *) handle; /* get vnode */ if (vp->v_type != VCHR) { uobj = uvn_attach((void *) vp, (flags & MAP_SHARED) ? maxprot : (maxprot & ~VM_PROT_WRITE)); #ifndef UBC /* * XXXCDC: hack from old code * don't allow vnodes which have been mapped * shared-writeable to persist [forces them to be * flushed out when last reference goes]. * XXXCDC: interesting side effect: avoids a bug. * note that in WRITE [ufs_readwrite.c] that we * allocate buffer, uncache, and then do the write. * the problem with this is that if the uncache causes * VM data to be flushed to the same area of the file * we are writing to... in that case we've got the * buffer locked and our process goes to sleep forever. * * XXXCDC: checking maxprot protects us from the * "persistbug" program but this is not a long term * solution. * * XXXCDC: we don't bother calling uncache with the vp * VOP_LOCKed since we know that we are already * holding a valid reference to the uvn (from the * uvn_attach above), and thus it is impossible for * the uncache to kill the uvn and trigger I/O. */ if (flags & MAP_SHARED) { if ((prot & VM_PROT_WRITE) || (maxprot & VM_PROT_WRITE)) { uvm_vnp_uncache(vp); } } #else /* XXX for now, attach doesn't gain a ref */ vref(vp); #endif } else { uobj = udv_attach((void *) &vp->v_rdev, (flags & MAP_SHARED) ? maxprot : (maxprot & ~VM_PROT_WRITE), foff, size); /* * XXX Some devices don't like to be mapped with * XXX PROT_EXEC, but we don't really have a * XXX better way of handling this, right now */ if (uobj == NULL && (prot & PROT_EXEC) == 0) { maxprot &= ~VM_PROT_EXECUTE; uobj = udv_attach((void *) &vp->v_rdev, (flags & MAP_SHARED) ? maxprot : (maxprot & ~VM_PROT_WRITE), foff, size); } advice = UVM_ADV_RANDOM; } if (uobj == NULL) return((vp->v_type == VREG) ? ENOMEM : EINVAL); if ((flags & MAP_SHARED) == 0) uvmflag |= UVM_FLAG_COPYONW; } /* * set up mapping flags */ uvmflag = UVM_MAPFLAG(prot, maxprot, (flags & MAP_SHARED) ? UVM_INH_SHARE : UVM_INH_COPY, advice, uvmflag); error = uvm_map(map, addr, size, uobj, foff, align, uvmflag); if (error == 0) { /* * POSIX 1003.1b -- if our address space was configured * to lock all future mappings, wire the one we just made. */ if (prot == VM_PROT_NONE) { /* * No more work to do in this case. */ return (0); } vm_map_lock(map); if (map->flags & VM_MAP_WIREFUTURE) { if ((atop(size) + uvmexp.wired) > uvmexp.wiredmax #ifdef pmap_wired_count || (locklimit != 0 && (size + ptoa(pmap_wired_count(vm_map_pmap(map)))) > locklimit) #endif ) { error = ENOMEM; vm_map_unlock(map); /* unmap the region! */ uvm_unmap(map, *addr, *addr + size); goto bad; } /* * uvm_map_pageable() always returns the map * unlocked. */ error = uvm_map_pageable(map, *addr, *addr + size, FALSE, UVM_LK_ENTER); if (error != 0) { /* unmap the region! */ uvm_unmap(map, *addr, *addr + size); goto bad; } return (0); } vm_map_unlock(map); return (0); } /* * errors: first detach from the uobj, if any. */ if (uobj) uobj->pgops->pgo_detach(uobj); bad: return (error); }