/* $OpenBSD: uvm_glue.c,v 1.47 2007/05/26 20:26:51 pedro Exp $ */ /* $NetBSD: uvm_glue.c,v 1.44 2001/02/06 19:54:44 eeh Exp $ */ /* * Copyright (c) 1997 Charles D. Cranor and Washington University. * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Charles D. Cranor, * Washington University, the 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. * * @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 * from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 chs Exp * * * 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. */ /* * uvm_glue.c: glue functions */ #include #include #include #include #include #include #ifdef SYSVSHM #include #endif #include #include #include /* * XXXCDC: do these really belong here? */ int readbuffers = 0; /* allow KGDB to read kern buffer pool */ /* XXX: see uvm_kernacc */ /* * uvm_kernacc: can the kernel access a region of memory * * - called from malloc [DIAGNOSTIC], and /dev/kmem driver (mem.c) */ boolean_t uvm_kernacc(addr, len, rw) caddr_t addr; size_t len; int rw; { boolean_t rv; vaddr_t saddr, eaddr; vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; saddr = trunc_page((vaddr_t)addr); eaddr = round_page((vaddr_t)addr + len); vm_map_lock_read(kernel_map); rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot); vm_map_unlock_read(kernel_map); return(rv); } #ifdef KGDB /* * Change protections on kernel pages from addr to addr+len * (presumably so debugger can plant a breakpoint). * * We force the protection change at the pmap level. If we were * to use vm_map_protect a change to allow writing would be lazily- * applied meaning we would still take a protection fault, something * we really don't want to do. It would also fragment the kernel * map unnecessarily. We cannot use pmap_protect since it also won't * enforce a write-enable request. Using pmap_enter is the only way * we can ensure the change takes place properly. */ void uvm_chgkprot(addr, len, rw) caddr_t addr; size_t len; int rw; { vm_prot_t prot; paddr_t pa; vaddr_t sva, eva; prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE; eva = round_page((vaddr_t)addr + len); for (sva = trunc_page((vaddr_t)addr); sva < eva; sva += PAGE_SIZE) { /* * Extract physical address for the page. * We use a cheezy hack to differentiate physical * page 0 from an invalid mapping, not that it * really matters... */ if (pmap_extract(pmap_kernel(), sva, &pa) == FALSE) panic("chgkprot: invalid page"); pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED); } pmap_update(pmap_kernel()); } #endif /* * uvm_vslock: wire user memory for I/O * * - called from physio and sys___sysctl * - XXXCDC: consider nuking this (or making it a macro?) */ int uvm_vslock(p, addr, len, access_type) struct proc *p; caddr_t addr; size_t len; vm_prot_t access_type; { vm_map_t map; vaddr_t start, end; int rv; map = &p->p_vmspace->vm_map; start = trunc_page((vaddr_t)addr); end = round_page((vaddr_t)addr + len); if (end <= start) return (EINVAL); rv = uvm_fault_wire(map, start, end, access_type); return (rv); } /* * uvm_vsunlock: unwire user memory wired by uvm_vslock() * * - called from physio and sys___sysctl * - XXXCDC: consider nuking this (or making it a macro?) */ void uvm_vsunlock(p, addr, len) struct proc *p; caddr_t addr; size_t len; { vaddr_t start, end; start = trunc_page((vaddr_t)addr); end = round_page((vaddr_t)addr + len); if (end <= start) return; uvm_fault_unwire(&p->p_vmspace->vm_map, start, end); } /* * uvm_fork: fork a virtual address space * * - the address space is copied as per parent map's inherit values * - a new "user" structure is allocated for the child process * [filled in by MD layer...] * - if specified, the child gets a new user stack described by * stack and stacksize * - NOTE: the kernel stack may be at a different location in the child * process, and thus addresses of automatic variables may be invalid * after cpu_fork returns in the child process. We do nothing here * after cpu_fork returns. * - XXXCDC: we need a way for this to return a failure value rather * than just hang */ void uvm_fork(p1, p2, shared, stack, stacksize, func, arg) struct proc *p1, *p2; boolean_t shared; void *stack; size_t stacksize; void (*func)(void *); void *arg; { struct user *up = p2->p_addr; if (shared == TRUE) { p2->p_vmspace = NULL; uvmspace_share(p1, p2); /* share vmspace */ } else p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */ #ifdef PMAP_UAREA /* Tell the pmap this is a u-area mapping */ PMAP_UAREA((vaddr_t)up); #endif /* * p_stats currently points at a field in the user struct. Copy * parts of p_stats, and zero out the rest. */ p2->p_stats = &up->u_stats; memset(&up->u_stats.pstat_startzero, 0, ((caddr_t)&up->u_stats.pstat_endzero - (caddr_t)&up->u_stats.pstat_startzero)); memcpy(&up->u_stats.pstat_startcopy, &p1->p_stats->pstat_startcopy, ((caddr_t)&up->u_stats.pstat_endcopy - (caddr_t)&up->u_stats.pstat_startcopy)); /* * cpu_fork() copy and update the pcb, and make the child ready * to run. If this is a normal user fork, the child will exit * directly to user mode via child_return() on its first time * slice and will not return here. If this is a kernel thread, * the specified entry point will be executed. */ cpu_fork(p1, p2, stack, stacksize, func, arg); } /* * uvm_exit: exit a virtual address space * * - the process passed to us is a dead (pre-zombie) process; we * are running on a different context now (the reaper). * - we must run in a separate thread because freeing the vmspace * of the dead process may block. */ void uvm_exit(struct proc *p) { uvmspace_free(p->p_vmspace); uvm_km_free(kernel_map, (vaddr_t)p->p_addr, USPACE); p->p_addr = NULL; } /* * uvm_init_limit: init per-process VM limits * * - called for process 0 and then inherited by all others. */ void uvm_init_limits(struct proc *p) { /* * Set up the initial limits on process VM. Set the maximum * resident set size to be all of (reasonably) available memory. * This causes any single, large process to start random page * replacement once it fills memory. */ p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free); } #ifdef DEBUG int enableswap = 1; int swapdebug = 0; #define SDB_FOLLOW 1 #define SDB_SWAPIN 2 #define SDB_SWAPOUT 4 #endif /* * uvm_scheduler: process zero main loop * * - if not enough memory, wake the pagedaemon and let it clear space. */ void uvm_scheduler(void) { /* * Nothing to do, back to sleep */ while (1) tsleep(&proc0, PVM, "scheduler", 0); } /* * swappable: is process "p" swappable? */ #define swappable(p) (((p)->p_flag & (P_SYSTEM | P_WEXIT)) == 0) /* * swapout_threads: find threads that can be swapped * * - called by the pagedaemon * - try and swap at least one processs * - processes that are sleeping or stopped for maxslp or more seconds * are swapped... otherwise the longest-sleeping or stopped process * is swapped, otherwise the longest resident process... */ void uvm_swapout_threads(void) { struct proc *p; struct proc *outp, *outp2; int outpri, outpri2; int didswap = 0; extern int maxslp; /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ #ifdef DEBUG if (!enableswap) return; #endif /* * outp/outpri : stop/sleep process with largest sleeptime < maxslp * outp2/outpri2: the longest resident process (its swap time) */ outp = outp2 = NULL; outpri = outpri2 = 0; LIST_FOREACH(p, &allproc, p_list) { if (!swappable(p)) continue; switch (p->p_stat) { case SRUN: if (p->p_swtime > outpri2) { outp2 = p; outpri2 = p->p_swtime; } continue; case SSLEEP: case SSTOP: if (p->p_slptime >= maxslp) { pmap_collect(p->p_vmspace->vm_map.pmap); didswap++; } else if (p->p_slptime > outpri) { outp = p; outpri = p->p_slptime; } continue; } } /* * If we didn't get rid of any real duds, toss out the next most * likely sleeping/stopped or running candidate. We only do this * if we are real low on memory since we don't gain much by doing * it. */ if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE))) { if ((p = outp) == NULL) p = outp2; #ifdef DEBUG if (swapdebug & SDB_SWAPOUT) printf("swapout_threads: no duds, try procp %p\n", p); #endif if (p) pmap_collect(p->p_vmspace->vm_map.pmap); } }