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.
 */
 
/*
 * 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.
 *
 * 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 <arch.h>
#include <list.h>
#include <debug.h>
 
/**
 * asidlock protects both the asids_allocated counter
 * and the list of address spaces that were already
 * assigned ASID.
 */
SPINLOCK_INITIALIZE(asidlock);
 
static count_t asids_allocated = 0;
 
/**
 * List of address spaces with assigned ASID.
 * When the system runs short of allocable
 * ASIDS, inactive address spaces are guaranteed
 * to be at the beginning of the list.
 */
LIST_INITIALIZE(as_with_asid_head);
 
 
/** Allocate free address space identifier.
 *
 * This code depends on the fact that ASIDS_ALLOCABLE
 * is greater than number of supported CPUs.
 *
 * @return New ASID.
 */
asid_t asid_get(void)
{
    ipl_t ipl;
    asid_t asid;
    link_t *tmp;
    as_t *as;
 
    /*
     * Check if there is an unallocated ASID.
     */
   
    ipl = interrupts_disable();
    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.
         */
        tmp = as_with_asid_head.next;
        ASSERT(tmp != &as_with_asid_head);
        list_remove(tmp);
       
        as = list_get_instance(tmp, as_t, as_with_asid_link);
        spinlock_lock(&as->lock);
 
        /*
         * Steal the ASID.
         * Note that the stolen ASID is not active.
         */
        asid = as->asid;
        ASSERT(asid != ASID_INVALID);
 
        /*
         * Get the system rid of the stolen ASID.
         */
        tlb_shootdown_start(TLB_INVL_ASID, asid, 0, 0);
        tlb_shootdown_finalize();
        tlb_invalidate_asid(asid);
        as->asid = ASID_INVALID;
       
        spinlock_unlock(&as->lock);
    } else {
 
        /*
         * There is at least one unallocated ASID.
         * Find it and assign it.
         */
 
        asid = asid_find_free();
        asids_allocated++;
    }
   
    spinlock_unlock(&asidlock);
    interrupts_restore(ipl);
   
    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);
}
 
/** Install ASID.
 *
 * This function is to be executed on each address space switch.
 *
 * @param as Address space.
 */
void asid_install(as_t *as)
{
    ipl_t ipl;
   
    ipl = interrupts_disable();
    spinlock_lock(&asidlock);
    spinlock_lock(&as->lock);
   
    if (as->asid != ASID_KERNEL) {
        if (as->asid != ASID_INVALID) {
            /*
             * This address space has valid ASID.
             * Remove 'as' from the list of address spaces
             * with assigned ASID, so that it can be later
             * appended to the tail of the same list.
             * This is to prevent stealing of ASIDs from
             * recently installed address spaces.
             */
            list_remove(&as->as_with_asid_link);
        } else {
            spinlock_unlock(&as->lock);
            spinlock_unlock(&asidlock);
   
            /*
             * This address space doesn't have ASID assigned.
             * It was stolen or the address space is being
             * installed for the first time.
             * Allocate new ASID for it.
             */
            as->asid = asid_get();
            spinlock_lock(&asidlock);
            spinlock_lock(&as->lock);
        }
   
        /*
         * Now it is sure that 'as' has ASID.
         * It is therefore appended to the list
         * of address spaces from which it can
         * be stolen.
         */
        list_append(&as->as_with_asid_link, &as_with_asid_head);
    }
   
    spinlock_unlock(&as->lock);
    spinlock_unlock(&asidlock);
    interrupts_restore(ipl);
}
 

Rev 727	Rev 740
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	* ASID management.	30	* ASID management.
31	*	31	*
32	* Modern processor architectures optimize TLB utilization	32	* Modern processor architectures optimize TLB utilization
33	* by using ASIDs (a.k.a. memory contexts on sparc64 and	33	* by using ASIDs (a.k.a. memory contexts on sparc64 and
34	* region identifiers on ia64). These ASIDs help to associate	34	* region identifiers on ia64). These ASIDs help to associate
35	* each TLB item with an address space, thus making	35	* each TLB item with an address space, thus making
36	* finer-grained TLB invalidation possible.	36	* finer-grained TLB invalidation possible.
37	*	37	*
38	* Unfortunatelly, there are usually less ASIDs available than	38	* Unfortunatelly, there are usually less ASIDs available than
39	* there can be unique as_t structures (i.e. address spaces	39	* there can be unique as_t structures (i.e. address spaces
40	* recognized by the kernel).	40	* recognized by the kernel).
41	*	41	*
42	* When system runs short of ASIDs, it will attempt to steal	42	* When system runs short of ASIDs, it will attempt to steal
43	* ASID from an address space that has not been active for	43	* ASID from an address space that has not been active for
44	* a while.	44	* a while.
45	*	45	*
46	* Architectures that don't have hardware support for address	46	* Architectures that don't have hardware support for address
47	* spaces do not compile with this file.	47	* spaces do not compile with this file.
48	*/	48	*/
49		49
50	#include <mm/asid.h>	50	#include <mm/asid.h>
51	#include <mm/as.h>	51	#include <mm/as.h>
52	#include <mm/tlb.h>	52	#include <mm/tlb.h>
53	#include <arch/mm/asid.h>	53	#include <arch/mm/asid.h>
54	#include <synch/spinlock.h>	54	#include <synch/spinlock.h>
55	#include <arch.h>	55	#include <arch.h>
56	#include <list.h>	56	#include <list.h>
57	#include <debug.h>	57	#include <debug.h>
58		58
59	/**	59	/**
60	* asidlock protects both the asids_allocated counter	60	* asidlock protects both the asids_allocated counter
61	* and the list of address spaces that were already	61	* and the list of address spaces that were already
62	* assigned ASID.	62	* assigned ASID.
63	*/	63	*/
64	SPINLOCK_INITIALIZE(asidlock);	64	SPINLOCK_INITIALIZE(asidlock);
65		65
66	static count_t asids_allocated = 0;	66	static count_t asids_allocated = 0;
67		67
68	/**	68	/**
69	* List of address spaces with assigned ASID.	69	* List of address spaces with assigned ASID.
70	* When the system runs short of allocable	70	* When the system runs short of allocable
71	* ASIDS, inactive address spaces are guaranteed	71	* ASIDS, inactive address spaces are guaranteed
72	* to be at the beginning of the list.	72	* to be at the beginning of the list.
73	*/	73	*/
74	LIST_INITIALIZE(as_with_asid_head);	74	LIST_INITIALIZE(as_with_asid_head);
75		75
76		76
77	/** Allocate free address space identifier.	77	/** Allocate free address space identifier.
78	*	78	*
79	* This code depends on the fact that ASIDS_ALLOCABLE	79	* This code depends on the fact that ASIDS_ALLOCABLE
80	* is greater than number of supported CPUs.	80	* is greater than number of supported CPUs.
81	*	81	*
82	* @return New ASID.	82	* @return New ASID.
83	*/	83	*/
84	asid_t asid_get(void)	84	asid_t asid_get(void)
85	{	85	{
86	ipl_t ipl;	86	ipl_t ipl;
87	asid_t asid;	87	asid_t asid;
88	link_t *tmp;	88	link_t *tmp;
89	as_t *as;	89	as_t *as;
90		90
91	/*	91	/*
92	* Check if there is an unallocated ASID.	92	* Check if there is an unallocated ASID.
93	*/	93	*/
94		94
95	ipl = interrupts_disable();	95	ipl = interrupts_disable();
96	spinlock_lock(&asidlock);	96	spinlock_lock(&asidlock);
97	if (asids_allocated == ASIDS_ALLOCABLE) {	97	if (asids_allocated == ASIDS_ALLOCABLE) {
98		98
99	/*	99	/*
100	* All ASIDs are already allocated.	100	* All ASIDs are already allocated.
101	* Resort to stealing.	101	* Resort to stealing.
102	*/	102	*/
103		103
104	/*	104	/*
105	* Remove the first item on the list.	105	* Remove the first item on the list.
106	* It is guaranteed to belong to an	106	* It is guaranteed to belong to an
107	* inactive address space.	107	* inactive address space.
108	*/	108	*/
109	tmp = as_with_asid_head.next;	109	tmp = as_with_asid_head.next;
110	ASSERT(tmp != &as_with_asid_head);	110	ASSERT(tmp != &as_with_asid_head);
111	list_remove(tmp);	111	list_remove(tmp);
112		112
113	as = list_get_instance(tmp, as_t, as_with_asid_link);	113	as = list_get_instance(tmp, as_t, as_with_asid_link);
114	spinlock_lock(&as->lock);	114	spinlock_lock(&as->lock);
115		115
116	/*	116	/*
117	* Steal the ASID.	117	* Steal the ASID.
118	* Note that the stolen ASID is not active.	118	* Note that the stolen ASID is not active.
119	*/	119	*/
120	asid = as->asid;	120	asid = as->asid;
121	ASSERT(asid != ASID_INVALID);	121	ASSERT(asid != ASID_INVALID);
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_shootdown_finalize();	127	tlb_shootdown_finalize();
-		128	tlb_invalidate_asid(asid);
128	as->asid = ASID_INVALID;	129	as->asid = ASID_INVALID;
129		130
130	spinlock_unlock(&as->lock);	131	spinlock_unlock(&as->lock);
131	} else {	132	} else {
132		133
133	/*	134	/*
134	* There is at least one unallocated ASID.	135	* There is at least one unallocated ASID.
135	* Find it and assign it.	136	* Find it and assign it.
136	*/	137	*/
137		138
138	asid = asid_find_free();	139	asid = asid_find_free();
139	asids_allocated++;	140	asids_allocated++;
140	}	141	}
141		142
142	spinlock_unlock(&asidlock);	143	spinlock_unlock(&asidlock);
143	interrupts_restore(ipl);	144	interrupts_restore(ipl);
144		145
145	return asid;	146	return asid;
146	}	147	}
147		148
148	/** Release address space identifier.	149	/** Release address space identifier.
149	*	150	*
150	* This code relies on architecture	151	* This code relies on architecture
151	* dependent functionality.	152	* dependent functionality.
152	*	153	*
153	* @param asid ASID to be released.	154	* @param asid ASID to be released.
154	*/	155	*/
155	void asid_put(asid_t asid)	156	void asid_put(asid_t asid)
156	{	157	{
157	ipl_t ipl;	158	ipl_t ipl;
158		159
159	ipl = interrupts_disable();	160	ipl = interrupts_disable();
160	spinlock_lock(&asidlock);	161	spinlock_lock(&asidlock);
161		162
162	asids_allocated--;	163	asids_allocated--;
163	asid_put_arch(asid);	164	asid_put_arch(asid);
164		165
165	spinlock_unlock(&asidlock);	166	spinlock_unlock(&asidlock);
166	interrupts_restore(ipl);	167	interrupts_restore(ipl);
167	}	168	}
168		169
169	/** Install ASID.	170	/** Install ASID.
170	*	171	*
171	* This function is to be executed on each address space switch.	172	* This function is to be executed on each address space switch.
172	*	173	*
173	* @param as Address space.	174	* @param as Address space.
174	*/	175	*/
175	void asid_install(as_t *as)	176	void asid_install(as_t *as)
176	{	177	{
177	ipl_t ipl;	178	ipl_t ipl;
178		179
179	ipl = interrupts_disable();	180	ipl = interrupts_disable();
180	spinlock_lock(&asidlock);	181	spinlock_lock(&asidlock);
181	spinlock_lock(&as->lock);	182	spinlock_lock(&as->lock);
182		183
183	if (as->asid != ASID_KERNEL) {	184	if (as->asid != ASID_KERNEL) {
184	if (as->asid != ASID_INVALID) {	185	if (as->asid != ASID_INVALID) {
185	/*	186	/*
186	* This address space has valid ASID.	187	* This address space has valid ASID.
187	* Remove 'as' from the list of address spaces	188	* Remove 'as' from the list of address spaces
188	* with assigned ASID, so that it can be later	189	* with assigned ASID, so that it can be later
189	* appended to the tail of the same list.	190	* appended to the tail of the same list.
190	* This is to prevent stealing of ASIDs from	191	* This is to prevent stealing of ASIDs from
191	* recently installed address spaces.	192	* recently installed address spaces.
192	*/	193	*/
193	list_remove(&as->as_with_asid_link);	194	list_remove(&as->as_with_asid_link);
194	} else {	195	} else {
195	spinlock_unlock(&as->lock);	196	spinlock_unlock(&as->lock);
196	spinlock_unlock(&asidlock);	197	spinlock_unlock(&asidlock);
197		198
198	/*	199	/*
199	* This address space doesn't have ASID assigned.	200	* This address space doesn't have ASID assigned.
200	* It was stolen or the address space is being	201	* It was stolen or the address space is being
201	* installed for the first time.	202	* installed for the first time.
202	* Allocate new ASID for it.	203	* Allocate new ASID for it.
203	*/	204	*/
204	as->asid = asid_get();	205	as->asid = asid_get();
205	spinlock_lock(&asidlock);	206	spinlock_lock(&asidlock);
206	spinlock_lock(&as->lock);	207	spinlock_lock(&as->lock);
207	}	208	}
208		209
209	/*	210	/*
210	* Now it is sure that 'as' has ASID.	211	* Now it is sure that 'as' has ASID.
211	* It is therefore appended to the list	212	* It is therefore appended to the list
212	* of address spaces from which it can	213	* of address spaces from which it can
213	* be stolen.	214	* be stolen.
214	*/	215	*/
215	list_append(&as->as_with_asid_link, &as_with_asid_head);	216	list_append(&as->as_with_asid_link, &as_with_asid_head);
216	}	217	}
217		218
218	spinlock_unlock(&as->lock);	219	spinlock_unlock(&as->lock);
219	spinlock_unlock(&asidlock);	220	spinlock_unlock(&asidlock);
220	interrupts_restore(ipl);	221	interrupts_restore(ipl);
221	}	222	}
222		223

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/genarch/src/mm/asid.c – Rev 727 → 740