FreeBSD/Linux Kernel Cross Reference
sys/powerpc/powerpc/vm_machdep.c

     /*-
      * Copyright (c) 1982, 1986 The Regents of the University of California.
      * Copyright (c) 1989, 1990 William Jolitz
      * Copyright (c) 1994 John Dyson
      * 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, and William Jolitz.
     *
     * 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 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: @(#)vm_machdep.c  7.3 (Berkeley) 5/13/91
     *      Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
     * $FreeBSD: releng/10.2/sys/powerpc/powerpc/vm_machdep.c 265952 2014-05-13 16:50:10Z ian $
     */
    /*-
     * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
     * All rights reserved.
     *
     * Author: Chris G. Demetriou
     *
     * 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/param.h>
    #include <sys/systm.h>
    #include <sys/proc.h>
    #include <sys/malloc.h>
    #include <sys/bio.h>
    #include <sys/buf.h>
    #include <sys/ktr.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/vnode.h>
    #include <sys/vmmeter.h>
    #include <sys/kernel.h>
    #include <sys/mbuf.h>
    #include <sys/sf_buf.h>
    #include <sys/sysctl.h>
    #include <sys/sysent.h>
    #include <sys/unistd.h>
    
    #include <machine/cpu.h>
    #include <machine/fpu.h>
    #include <machine/frame.h>
    #include <machine/md_var.h>
    #include <machine/pcb.h>
    
    #include <dev/ofw/openfirm.h>
    
    #include <vm/vm.h>
    #include <vm/vm_param.h>
    #include <vm/vm_kern.h>
    #include <vm/vm_page.h>
   #include <vm/vm_map.h>
   #include <vm/vm_extern.h>
   
   /*
    * On systems without a direct mapped region (e.g. PPC64),
    * we use the same code as the Book E implementation. Since
    * we need to have runtime detection of this, define some machinery
    * for sf_bufs in this case, and ignore it on systems with direct maps.
    */
   
   #ifndef NSFBUFS
   #define NSFBUFS         (512 + maxusers * 16)
   #endif
   
   static int nsfbufs;
   static int nsfbufspeak;
   static int nsfbufsused;
   
   SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufs, CTLFLAG_RDTUN, &nsfbufs, 0,
       "Maximum number of sendfile(2) sf_bufs available");
   SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufspeak, CTLFLAG_RD, &nsfbufspeak, 0,
       "Number of sendfile(2) sf_bufs at peak usage");
   SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufsused, CTLFLAG_RD, &nsfbufsused, 0,
       "Number of sendfile(2) sf_bufs in use");
   
   static void sf_buf_init(void *arg);
   SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL);
    
   LIST_HEAD(sf_head, sf_buf);
    
   /* A hash table of active sendfile(2) buffers */
   static struct sf_head *sf_buf_active;
   static u_long sf_buf_hashmask;
   
   #define SF_BUF_HASH(m)  (((m) - vm_page_array) & sf_buf_hashmask)
   
   static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
   static u_int sf_buf_alloc_want;
   
   /*
    * A lock used to synchronize access to the hash table and free list
    */
   static struct mtx sf_buf_lock;
   
   #ifdef __powerpc64__
   extern uintptr_t tocbase;
   #endif
   
   
   /*
    * Finish a fork operation, with process p2 nearly set up.
    * Copy and update the pcb, set up the stack so that the child
    * ready to run and return to user mode.
    */
   void
   cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags)
   {
           struct  trapframe *tf;
           struct  callframe *cf;
           struct  pcb *pcb;
   
           KASSERT(td1 == curthread || td1 == &thread0,
               ("cpu_fork: p1 not curproc and not proc0"));
           CTR3(KTR_PROC, "cpu_fork: called td1=%p p2=%p flags=%x",
               td1, p2, flags);
   
           if ((flags & RFPROC) == 0)
                   return;
   
           pcb = (struct pcb *)((td2->td_kstack +
               td2->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb)) & ~0x2fUL);
           td2->td_pcb = pcb;
   
           /* Copy the pcb */
           bcopy(td1->td_pcb, pcb, sizeof(struct pcb));
   
           /*
            * Create a fresh stack for the new process.
            * Copy the trap frame for the return to user mode as if from a
            * syscall.  This copies most of the user mode register values.
            */
           tf = (struct trapframe *)pcb - 1;
           bcopy(td1->td_frame, tf, sizeof(*tf));
   
           /* Set up trap frame. */
           tf->fixreg[FIRSTARG] = 0;
           tf->fixreg[FIRSTARG + 1] = 0;
           tf->cr &= ~0x10000000;
   
           td2->td_frame = tf;
   
           cf = (struct callframe *)tf - 1;
           memset(cf, 0, sizeof(struct callframe));
           #ifdef __powerpc64__
           cf->cf_toc = tocbase;
           #endif
           cf->cf_func = (register_t)fork_return;
           cf->cf_arg0 = (register_t)td2;
           cf->cf_arg1 = (register_t)tf;
   
           pcb->pcb_sp = (register_t)cf;
           KASSERT(pcb->pcb_sp % 16 == 0, ("stack misaligned"));
           #ifdef __powerpc64__
           pcb->pcb_lr = ((register_t *)fork_trampoline)[0];
           pcb->pcb_toc = ((register_t *)fork_trampoline)[1];
           #else
           pcb->pcb_lr = (register_t)fork_trampoline;
           #endif
           #ifdef AIM
           pcb->pcb_cpu.aim.usr_vsid = 0;
           #endif
   
           /* Setup to release spin count in fork_exit(). */
           td2->td_md.md_spinlock_count = 1;
           td2->td_md.md_saved_msr = PSL_KERNSET;
   
           /*
            * Now cpu_switch() can schedule the new process.
            */
   }
   
   /*
    * Intercept the return address from a freshly forked process that has NOT
    * been scheduled yet.
    *
    * This is needed to make kernel threads stay in kernel mode.
    */
   void
   cpu_set_fork_handler(struct thread *td, void (*func)(void *), void *arg)
   {
           struct callframe *cf;
   
           CTR4(KTR_PROC, "%s called with td=%p func=%p arg=%p",
               __func__, td, func, arg);
   
           cf = (struct callframe *)td->td_pcb->pcb_sp;
   
           cf->cf_func = (register_t)func;
           cf->cf_arg0 = (register_t)arg;
   }
   
   void
   cpu_exit(struct thread *td)
   {
   
   }
   
   /*
    * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
    */
   static void
   sf_buf_init(void *arg)
   {
           struct sf_buf *sf_bufs;
           vm_offset_t sf_base;
           int i;
   
           /* Don't bother on systems with a direct map */
           if (hw_direct_map)
                   return;
   
           nsfbufs = NSFBUFS;
           TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
   
           sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
           TAILQ_INIT(&sf_buf_freelist);
           sf_base = kva_alloc(nsfbufs * PAGE_SIZE);
           sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
               M_NOWAIT | M_ZERO);
   
           for (i = 0; i < nsfbufs; i++) {
                   sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
                   TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
           }
           sf_buf_alloc_want = 0;
           mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
   }
   
   /*
    * Get an sf_buf from the freelist. Will block if none are available.
    */
   struct sf_buf *
   sf_buf_alloc(struct vm_page *m, int flags)
   {
           struct sf_head *hash_list;
           struct sf_buf *sf;
           int error;
   
           if (hw_direct_map) {
                   /* Shortcut the direct mapped case */
                   return ((struct sf_buf *)m);
           }
   
           hash_list = &sf_buf_active[SF_BUF_HASH(m)];
           mtx_lock(&sf_buf_lock);
           LIST_FOREACH(sf, hash_list, list_entry) {
                   if (sf->m == m) {
                           sf->ref_count++;
                           if (sf->ref_count == 1) {
                                   TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
                                   nsfbufsused++;
                                   nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
                           }
                           goto done;
                   }
           }
   
           while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
                   if (flags & SFB_NOWAIT)
                           goto done;
   
                   sf_buf_alloc_want++;
                   SFSTAT_INC(sf_allocwait);
                   error = msleep(&sf_buf_freelist, &sf_buf_lock,
                       (flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
                   sf_buf_alloc_want--;
   
                   /*
                    * If we got a signal, don't risk going back to sleep.
                    */
                   if (error)
                           goto done;
           }
   
           TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
           if (sf->m != NULL)
                   LIST_REMOVE(sf, list_entry);
   
           LIST_INSERT_HEAD(hash_list, sf, list_entry);
           sf->ref_count = 1;
           sf->m = m;
           nsfbufsused++;
           nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
           pmap_qenter(sf->kva, &sf->m, 1);
   done:
           mtx_unlock(&sf_buf_lock);
           return (sf);
   }
   
   /*
    * Detach mapped page and release resources back to the system.
    *
    * Remove a reference from the given sf_buf, adding it to the free
    * list when its reference count reaches zero. A freed sf_buf still,
    * however, retains its virtual-to-physical mapping until it is
    * recycled or reactivated by sf_buf_alloc(9).
    */
   void
   sf_buf_free(struct sf_buf *sf)
   {
           if (hw_direct_map)
                   return;
   
           mtx_lock(&sf_buf_lock);
           sf->ref_count--;
           if (sf->ref_count == 0) {
                   TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
                   nsfbufsused--;
   
                   if (sf_buf_alloc_want > 0)
                           wakeup(&sf_buf_freelist);
           }
           mtx_unlock(&sf_buf_lock);
   }
   
   /*
    * Software interrupt handler for queued VM system processing.
    */
   void
   swi_vm(void *dummy)
   {
   
           if (busdma_swi_pending != 0)
                   busdma_swi();
   }
   
   /*
    * Tell whether this address is in some physical memory region.
    * Currently used by the kernel coredump code in order to avoid
    * dumping the ``ISA memory hole'' which could cause indefinite hangs,
    * or other unpredictable behaviour.
    */
   int
   is_physical_memory(vm_offset_t addr)
   {
   
           /*
            * stuff other tests for known memory-mapped devices (PCI?)
            * here
            */
           return (1);
   }
   
   /*
    * CPU threading functions related to the VM layer. These could be used
    * to map the SLB bits required for the kernel stack instead of forcing a
    * fixed-size KVA.
    */
   
   void
   cpu_thread_swapin(struct thread *td)
   {
   
   }
   
   void
   cpu_thread_swapout(struct thread *td)
   {
   
   }
   

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