WebSVN – HelenOS-historic – Diff – /kernel/trunk/genarch/src/mm/asid.c


/*
 * Copyright (C) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */
 
/**
 * @file    asid.c
 * @brief   ASID management.
 *
 * Modern processor architectures optimize TLB utilization
 * by using ASIDs (a.k.a. memory contexts on sparc64 and
 * region identifiers on ia64). These ASIDs help to associate
 * each TLB item with an address space, thus making
 * finer-grained TLB invalidation possible.
 *
 * Unfortunatelly, there are usually less ASIDs available than
 * there can be unique as_t structures (i.e. address spaces
 * recognized by the kernel).
 *
 * When system runs short of ASIDs, it will attempt to steal
 * ASID from an address space that has not been active for
 * a while.
 *
 * This code depends on the fact that ASIDS_ALLOCABLE
 * is greater than number of supported CPUs (i.e. the
 * amount of concurently active address spaces).
 *
 * Architectures that don't have hardware support for address
 * spaces do not compile with this file.
 */
 
#include <mm/asid.h>
#include <mm/as.h>
#include <mm/tlb.h>
#include <arch/mm/asid.h>
#include <synch/spinlock.h>
#include <synch/mutex.h>
#include <arch.h>
#include <adt/list.h>
#include <debug.h>
 
/**
 * asidlock protects the asids_allocated counter.
 */
SPINLOCK_INITIALIZE(asidlock);
 
static count_t asids_allocated = 0;
 
/** Allocate free address space identifier.
 *
 * Interrupts must be disabled and inactive_as_with_asid_lock must be held
 * prior to this call
 *
 * @return New ASID.
 */
asid_t asid_get(void)
{
    asid_t asid;
    link_t *tmp;
    as_t *as;
 
    /*
     * Check if there is an unallocated ASID.
     */
   
    spinlock_lock(&asidlock);
    if (asids_allocated == ASIDS_ALLOCABLE) {
 
        /*
         * All ASIDs are already allocated.
         * Resort to stealing.
         */
       
        /*
         * Remove the first item on the list.
         * It is guaranteed to belong to an
         * inactive address space.
         */
        ASSERT(!list_empty(&inactive_as_with_asid_head));
        tmp = inactive_as_with_asid_head.next;
        list_remove(tmp);
       
        as = list_get_instance(tmp, as_t, inactive_as_with_asid_link);
        mutex_lock_active(&as->lock);
 
        /*
         * Steal the ASID.
         * Note that the stolen ASID is not active.
         */
        asid = as->asid;
        ASSERT(asid != ASID_INVALID);
 
        /*
         * Notify the address space from wich the ASID
         * was stolen by invalidating its asid member.
         */
        as->asid = ASID_INVALID;
        mutex_unlock(&as->lock);
 
        /*
         * Get the system rid of the stolen ASID.
         */
        tlb_shootdown_start(TLB_INVL_ASID, asid, 0, 0);
        tlb_invalidate_asid(asid);
        tlb_shootdown_finalize();
    } else {
 
        /*
         * There is at least one unallocated ASID.
         * Find it and assign it.
         */
 
        asid = asid_find_free();
        asids_allocated++;
 
        /*
         * Purge the allocated rid from TLBs.
         */
        tlb_shootdown_start(TLB_INVL_ASID, asid, 0, 0);
        tlb_invalidate_asid(asid);
        tlb_shootdown_finalize();
    }
   
    spinlock_unlock(&asidlock);
   
    return asid;
}
 
/** Release address space identifier.
 *
 * This code relies on architecture
 * dependent functionality.
 *
 * @param asid ASID to be released.
 */
void asid_put(asid_t asid)
{
    ipl_t ipl;
 
    ipl = interrupts_disable();
    spinlock_lock(&asidlock);
 
    asids_allocated--;
    asid_put_arch(asid);
   
    spinlock_unlock(&asidlock);
    interrupts_restore(ipl);
}
 

Rev 1636	Rev 1637
1	/*	1	/*
2	* Copyright (C) 2006 Jakub Jermar	2	* Copyright (C) 2006 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/**	29	/**
30	* @file asid.c	30	* @file asid.c
31	* @brief ASID management.	31	* @brief ASID management.
32	*	32	*
33	* Modern processor architectures optimize TLB utilization	33	* Modern processor architectures optimize TLB utilization
34	* by using ASIDs (a.k.a. memory contexts on sparc64 and	34	* by using ASIDs (a.k.a. memory contexts on sparc64 and
35	* region identifiers on ia64). These ASIDs help to associate	35	* region identifiers on ia64). These ASIDs help to associate
36	* each TLB item with an address space, thus making	36	* each TLB item with an address space, thus making
37	* finer-grained TLB invalidation possible.	37	* finer-grained TLB invalidation possible.
38	*	38	*
39	* Unfortunatelly, there are usually less ASIDs available than	39	* Unfortunatelly, there are usually less ASIDs available than
40	* there can be unique as_t structures (i.e. address spaces	40	* there can be unique as_t structures (i.e. address spaces
41	* recognized by the kernel).	41	* recognized by the kernel).
42	*	42	*
43	* When system runs short of ASIDs, it will attempt to steal	43	* When system runs short of ASIDs, it will attempt to steal
44	* ASID from an address space that has not been active for	44	* ASID from an address space that has not been active for
45	* a while.	45	* a while.
46	*	46	*
47	* This code depends on the fact that ASIDS_ALLOCABLE	47	* This code depends on the fact that ASIDS_ALLOCABLE
48	* is greater than number of supported CPUs (i.e. the	48	* is greater than number of supported CPUs (i.e. the
49	* amount of concurently active address spaces).	49	* amount of concurently active address spaces).
50	*	50	*
51	* Architectures that don't have hardware support for address	51	* Architectures that don't have hardware support for address
52	* spaces do not compile with this file.	52	* spaces do not compile with this file.
53	*/	53	*/
54		54
55	#include <mm/asid.h>	55	#include <mm/asid.h>
56	#include <mm/as.h>	56	#include <mm/as.h>
57	#include <mm/tlb.h>	57	#include <mm/tlb.h>
58	#include <arch/mm/asid.h>	58	#include <arch/mm/asid.h>
59	#include <synch/spinlock.h>	59	#include <synch/spinlock.h>
60	#include <synch/mutex.h>	60	#include <synch/mutex.h>
61	#include <arch.h>	61	#include <arch.h>
62	#include <adt/list.h>	62	#include <adt/list.h>
63	#include <debug.h>	63	#include <debug.h>
64		64
65	/**	65	/**
66	* asidlock protects the asids_allocated counter.	66	* asidlock protects the asids_allocated counter.
67	*/	67	*/
68	SPINLOCK_INITIALIZE(asidlock);	68	SPINLOCK_INITIALIZE(asidlock);
69		69
70	static count_t asids_allocated = 0;	70	static count_t asids_allocated = 0;
71		71
72	/** Allocate free address space identifier.	72	/** Allocate free address space identifier.
73	*	73	*
74	* Interrupts must be disabled and as_lock must be held	74	* Interrupts must be disabled and inactive_as_with_asid_lock must be held
75	* prior to this call	75	* prior to this call
76	*	76	*
77	* @return New ASID.	77	* @return New ASID.
78	*/	78	*/
79	asid_t asid_get(void)	79	asid_t asid_get(void)
80	{	80	{
81	asid_t asid;	81	asid_t asid;
82	link_t *tmp;	82	link_t *tmp;
83	as_t *as;	83	as_t *as;
84		84
85	/*	85	/*
86	* Check if there is an unallocated ASID.	86	* Check if there is an unallocated ASID.
87	*/	87	*/
88		88
89	spinlock_lock(&asidlock);	89	spinlock_lock(&asidlock);
90	if (asids_allocated == ASIDS_ALLOCABLE) {	90	if (asids_allocated == ASIDS_ALLOCABLE) {
91		91
92	/*	92	/*
93	* All ASIDs are already allocated.	93	* All ASIDs are already allocated.
94	* Resort to stealing.	94	* Resort to stealing.
95	*/	95	*/
96		96
97	/*	97	/*
98	* Remove the first item on the list.	98	* Remove the first item on the list.
99	* It is guaranteed to belong to an	99	* It is guaranteed to belong to an
100	* inactive address space.	100	* inactive address space.
101	*/	101	*/
102	ASSERT(!list_empty(&inactive_as_with_asid_head));	102	ASSERT(!list_empty(&inactive_as_with_asid_head));
103	tmp = inactive_as_with_asid_head.next;	103	tmp = inactive_as_with_asid_head.next;
104	list_remove(tmp);	104	list_remove(tmp);
105		105
106	as = list_get_instance(tmp, as_t, inactive_as_with_asid_link);	106	as = list_get_instance(tmp, as_t, inactive_as_with_asid_link);
107	mutex_lock_active(&as->lock);	107	mutex_lock_active(&as->lock);
108		108
109	/*	109	/*
110	* Steal the ASID.	110	* Steal the ASID.
111	* Note that the stolen ASID is not active.	111	* Note that the stolen ASID is not active.
112	*/	112	*/
113	asid = as->asid;	113	asid = as->asid;
114	ASSERT(asid != ASID_INVALID);	114	ASSERT(asid != ASID_INVALID);
115		115
116	/*	116	/*
117	* Notify the address space from wich the ASID	117	* Notify the address space from wich the ASID
118	* was stolen by invalidating its asid member.	118	* was stolen by invalidating its asid member.
119	*/	119	*/
120	as->asid = ASID_INVALID;	120	as->asid = ASID_INVALID;
121	mutex_unlock(&as->lock);	121	mutex_unlock(&as->lock);
122		122
123	/*	123	/*
124	* Get the system rid of the stolen ASID.	124	* Get the system rid of the stolen ASID.
125	*/	125	*/
126	tlb_shootdown_start(TLB_INVL_ASID, asid, 0, 0);	126	tlb_shootdown_start(TLB_INVL_ASID, asid, 0, 0);
127	tlb_invalidate_asid(asid);	127	tlb_invalidate_asid(asid);
128	tlb_shootdown_finalize();	128	tlb_shootdown_finalize();
129	} else {	129	} else {
130		130
131	/*	131	/*
132	* There is at least one unallocated ASID.	132	* There is at least one unallocated ASID.
133	* Find it and assign it.	133	* Find it and assign it.
134	*/	134	*/
135		135
136	asid = asid_find_free();	136	asid = asid_find_free();
137	asids_allocated++;	137	asids_allocated++;
138		138
139	/*	139	/*
140	* Purge the allocated rid from TLBs.	140	* Purge the allocated rid from TLBs.
141	*/	141	*/
142	tlb_shootdown_start(TLB_INVL_ASID, asid, 0, 0);	142	tlb_shootdown_start(TLB_INVL_ASID, asid, 0, 0);
143	tlb_invalidate_asid(asid);	143	tlb_invalidate_asid(asid);
144	tlb_shootdown_finalize();	144	tlb_shootdown_finalize();
145	}	145	}
146		146
147	spinlock_unlock(&asidlock);	147	spinlock_unlock(&asidlock);
148		148
149	return asid;	149	return asid;
150	}	150	}
151		151
152	/** Release address space identifier.	152	/** Release address space identifier.
153	*	153	*
154	* This code relies on architecture	154	* This code relies on architecture
155	* dependent functionality.	155	* dependent functionality.
156	*	156	*
157	* @param asid ASID to be released.	157	* @param asid ASID to be released.
158	*/	158	*/
159	void asid_put(asid_t asid)	159	void asid_put(asid_t asid)
160	{	160	{
161	ipl_t ipl;	161	ipl_t ipl;
162		162
163	ipl = interrupts_disable();	163	ipl = interrupts_disable();
164	spinlock_lock(&asidlock);	164	spinlock_lock(&asidlock);
165		165
166	asids_allocated--;	166	asids_allocated--;
167	asid_put_arch(asid);	167	asid_put_arch(asid);
168		168
169	spinlock_unlock(&asidlock);	169	spinlock_unlock(&asidlock);
170	interrupts_restore(ipl);	170	interrupts_restore(ipl);
171	}	171	}
172		172

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/genarch/src/mm/asid.c – Rev 1636 → 1637