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pmap_pvt.c revision 1.3 
      1 /*	$NetBSD: pmap_pvt.c,v 1.3 2016/02/07 18:41:25 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __RCSID("$NetBSD: pmap_pvt.c,v 1.3 2016/02/07 18:41:25 riastradh Exp $");
     34 
     35 #include <sys/kmem.h>
     36 #include <sys/pserialize.h>
     37 
     38 #include <uvm/uvm.h>
     39 #include <uvm/pmap/pmap_pvt.h>
     40 
     41 /*
     42  * unmanaged pv-tracked ranges
     43  *
     44  * This is a linear list for now because the only user are the DRM
     45  * graphics drivers, with a single tracked range per device, for the
     46  * graphics aperture, so there are expected to be few of them.
     47  *
     48  * This is used only after the VM system is initialized well enough
     49  * that we can use kmem_alloc.
     50  */
     51 
     52 struct pv_track {
     53 	paddr_t			pvt_start;
     54 	psize_t			pvt_size;
     55 	struct pv_track		*pvt_next;
     56 	struct pmap_page	pvt_pages[];
     57 };
     58 
     59 static struct {
     60 	kmutex_t	lock;
     61 	pserialize_t	psz;
     62 	struct pv_track	*list;
     63 } pv_unmanaged __cacheline_aligned;
     64 
     65 void
     66 pmap_pv_init(void)
     67 {
     68 
     69 	mutex_init(&pv_unmanaged.lock, MUTEX_DEFAULT, IPL_NONE);
     70 	pv_unmanaged.psz = pserialize_create();
     71 	pv_unmanaged.list = NULL;
     72 }
     73 
     74 void
     75 pmap_pv_track(paddr_t start, psize_t size)
     76 {
     77 	struct pv_track *pvt;
     78 	size_t npages;
     79 
     80 	KASSERT(start == trunc_page(start));
     81 	KASSERT(size == trunc_page(size));
     82 
     83 	/* We may sleep for allocation.  */
     84 	ASSERT_SLEEPABLE();
     85 
     86 	npages = size >> PAGE_SHIFT;
     87 	pvt = kmem_zalloc(offsetof(struct pv_track, pvt_pages[npages]),
     88 	    KM_SLEEP);
     89 	pvt->pvt_start = start;
     90 	pvt->pvt_size = size;
     91 
     92 	mutex_enter(&pv_unmanaged.lock);
     93 	pvt->pvt_next = pv_unmanaged.list;
     94 	membar_producer();
     95 	pv_unmanaged.list = pvt;
     96 	mutex_exit(&pv_unmanaged.lock);
     97 }
     98 
     99 void
    100 pmap_pv_untrack(paddr_t start, psize_t size)
    101 {
    102 	struct pv_track **pvtp, *pvt;
    103 	size_t npages;
    104 
    105 	KASSERT(start == trunc_page(start));
    106 	KASSERT(size == trunc_page(size));
    107 
    108 	/* We may sleep for pserialize_perform.  */
    109 	ASSERT_SLEEPABLE();
    110 
    111 	mutex_enter(&pv_unmanaged.lock);
    112 	for (pvtp = &pv_unmanaged.list;
    113 	     (pvt = *pvtp) != NULL;
    114 	     pvtp = &pvt->pvt_next) {
    115 		if (pvt->pvt_start != start)
    116 			continue;
    117 		if (pvt->pvt_size != size)
    118 			panic("pmap_pv_untrack: pv-tracking at 0x%"PRIxPADDR
    119 			    ": 0x%"PRIxPSIZE" bytes, not 0x%"PRIxPSIZE" bytes",
    120 			    pvt->pvt_start, pvt->pvt_size, size);
    121 		*pvtp = pvt->pvt_next;
    122 		pserialize_perform(pv_unmanaged.psz);
    123 		pvt->pvt_next = NULL;
    124 		goto out;
    125 	}
    126 	panic("pmap_pv_untrack: pages not pv-tracked at 0x%"PRIxPADDR
    127 	    " (0x%"PRIxPSIZE" bytes)",
    128 	    start, size);
    129 out:	mutex_exit(&pv_unmanaged.lock);
    130 
    131 	npages = size >> PAGE_SHIFT;
    132 	kmem_free(pvt, offsetof(struct pv_track, pvt_pages[npages]));
    133 }
    134 
    135 struct pmap_page *
    136 pmap_pv_tracked(paddr_t pa)
    137 {
    138 	struct pv_track *pvt;
    139 	size_t pgno;
    140 	int s;
    141 
    142 	KASSERT(pa == trunc_page(pa));
    143 
    144 	s = pserialize_read_enter();
    145 	for (pvt = pv_unmanaged.list; pvt != NULL; pvt = pvt->pvt_next) {
    146 		membar_datadep_consumer();
    147 		if ((pvt->pvt_start <= pa) &&
    148 		    ((pa - pvt->pvt_start) < pvt->pvt_size))
    149 			break;
    150 	}
    151 	pserialize_read_exit(s);
    152 
    153 	if (pvt == NULL)
    154 		return NULL;
    155 	KASSERT(pvt->pvt_start <= pa);
    156 	KASSERT((pa - pvt->pvt_start) < pvt->pvt_size);
    157 	pgno = (pa - pvt->pvt_start) >> PAGE_SHIFT;
    158 	return &pvt->pvt_pages[pgno];
    159 }
    160 
    161