FreeBSD/Linux Kernel Cross Reference
sys/mips/include/pte.h
1 /*-
2 * Copyright (c) 2004-2010 Juli Mallett <jmallett@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/10.0/sys/mips/include/pte.h 257523 2013-11-01 20:30:19Z brooks $
27 */
28
29 #ifndef _MACHINE_PTE_H_
30 #define _MACHINE_PTE_H_
31
32 #ifndef _LOCORE
33 #if defined(__mips_n64) || defined(__mips_n32) /* PHYSADDR_64_BIT */
34 typedef uint64_t pt_entry_t;
35 #else
36 typedef uint32_t pt_entry_t;
37 #endif
38 typedef pt_entry_t *pd_entry_t;
39 #endif
40
41 /*
42 * TLB and PTE management. Most things operate within the context of
43 * EntryLo0,1, and begin with TLBLO_. Things which work with EntryHi
44 * start with TLBHI_. PTE bits begin with PTE_.
45 *
46 * Note that we use the same size VM and TLB pages.
47 */
48 #define TLB_PAGE_SHIFT (PAGE_SHIFT)
49 #define TLB_PAGE_SIZE (1 << TLB_PAGE_SHIFT)
50 #define TLB_PAGE_MASK (TLB_PAGE_SIZE - 1)
51
52 /*
53 * TLB PageMask register. Has mask bits set above the default, 4K, page mask.
54 */
55 #define TLBMASK_SHIFT (13)
56 #define TLBMASK_MASK ((PAGE_MASK >> TLBMASK_SHIFT) << TLBMASK_SHIFT)
57
58 /*
59 * FreeBSD/mips page-table entries take a near-identical format to MIPS TLB
60 * entries, each consisting of two 32-bit or 64-bit values ("EntryHi" and
61 * "EntryLo"). MIPS4k and MIPS64 both define certain bits in TLB entries as
62 * reserved, and these must be zero-filled by software. We overload these
63 * bits in PTE entries to hold PTE_ flags such as RO, W, and MANAGED.
64 * However, we must mask these out when writing to TLB entries to ensure that
65 * they do not become visible to hardware -- especially on MIPS64r2 which has
66 * an extended physical memory space.
67 *
68 * When using n64 and n32, shift software-defined bits into the MIPS64r2
69 * reserved range, which runs from bit 55 ... 63. In other configurations
70 * (32-bit MIPS4k and compatible), shift them out to bits 29 ... 31.
71 *
72 * NOTE: This means that for 32-bit use of CP0, we aren't able to set the top
73 * bit of PFN to a non-zero value, as software is using it! This physical
74 * memory size limit may not be sufficiently enforced elsewhere.
75 */
76 #if defined(__mips_n64) || defined(__mips_n32) /* PHYSADDR_64_BIT */
77 #define TLBLO_SWBITS_SHIFT (55)
78 #define TLBLO_SWBITS_CLEAR_SHIFT (9)
79 #define TLBLO_PFN_MASK 0x3FFFFFFC0ULL
80 #else
81 #define TLBLO_SWBITS_SHIFT (29)
82 #define TLBLO_SWBITS_CLEAR_SHIFT (3)
83 #define TLBLO_PFN_MASK (0x1FFFFFC0)
84 #endif
85 #define TLBLO_PFN_SHIFT (6)
86 #define TLBLO_SWBITS_MASK ((pt_entry_t)0x7 << TLBLO_SWBITS_SHIFT)
87 #define TLBLO_PA_TO_PFN(pa) ((((pa) >> TLB_PAGE_SHIFT) << TLBLO_PFN_SHIFT) & TLBLO_PFN_MASK)
88 #define TLBLO_PFN_TO_PA(pfn) ((vm_paddr_t)((pfn) >> TLBLO_PFN_SHIFT) << TLB_PAGE_SHIFT)
89 #define TLBLO_PTE_TO_PFN(pte) ((pte) & TLBLO_PFN_MASK)
90 #define TLBLO_PTE_TO_PA(pte) (TLBLO_PFN_TO_PA(TLBLO_PTE_TO_PFN((pte))))
91
92 /*
93 * XXX This comment is not correct for anything more modern than R4K.
94 *
95 * VPN for EntryHi register. Upper two bits select user, supervisor,
96 * or kernel. Bits 61 to 40 copy bit 63. VPN2 is bits 39 and down to
97 * as low as 13, down to PAGE_SHIFT, to index 2 TLB pages*. From bit 12
98 * to bit 8 there is a 5-bit 0 field. Low byte is ASID.
99 *
100 * XXX This comment is not correct for FreeBSD.
101 * Note that in FreeBSD, we map 2 TLB pages is equal to 1 VM page.
102 */
103 #define TLBHI_ASID_MASK (0xff)
104 #if defined(__mips_n64)
105 #define TLBHI_R_SHIFT 62
106 #define TLBHI_R_USER (0x00UL << TLBHI_R_SHIFT)
107 #define TLBHI_R_SUPERVISOR (0x01UL << TLBHI_R_SHIFT)
108 #define TLBHI_R_KERNEL (0x03UL << TLBHI_R_SHIFT)
109 #define TLBHI_R_MASK (0x03UL << TLBHI_R_SHIFT)
110 #define TLBHI_VA_R(va) ((va) & TLBHI_R_MASK)
111 #define TLBHI_FILL_SHIFT 40
112 #define TLBHI_VPN2_SHIFT (TLB_PAGE_SHIFT + 1)
113 #define TLBHI_VPN2_MASK (((~((1UL << TLBHI_VPN2_SHIFT) - 1)) << (63 - TLBHI_FILL_SHIFT)) >> (63 - TLBHI_FILL_SHIFT))
114 #define TLBHI_VA_TO_VPN2(va) ((va) & TLBHI_VPN2_MASK)
115 #define TLBHI_ENTRY(va, asid) ((TLBHI_VA_R((va))) /* Region. */ | \
116 (TLBHI_VA_TO_VPN2((va))) /* VPN2. */ | \
117 ((asid) & TLBHI_ASID_MASK))
118 #else /* !defined(__mips_n64) */
119 #define TLBHI_PAGE_MASK (2 * PAGE_SIZE - 1)
120 #define TLBHI_ENTRY(va, asid) (((va) & ~TLBHI_PAGE_MASK) | ((asid) & TLBHI_ASID_MASK))
121 #endif /* defined(__mips_n64) */
122
123 /*
124 * TLB flags managed in hardware:
125 * C: Cache attribute.
126 * D: Dirty bit. This means a page is writable. It is not
127 * set at first, and a write is trapped, and the dirty
128 * bit is set. See also PTE_RO.
129 * V: Valid bit. Obvious, isn't it?
130 * G: Global bit. This means that this mapping is present
131 * in EVERY address space, and to ignore the ASID when
132 * it is matched.
133 */
134 #define PTE_C(attr) ((attr & 0x07) << 3)
135 #define PTE_C_UNCACHED (PTE_C(MIPS_CCA_UNCACHED))
136 #define PTE_C_CACHE (PTE_C(MIPS_CCA_CACHED))
137 #define PTE_D 0x04
138 #define PTE_V 0x02
139 #define PTE_G 0x01
140
141 /*
142 * VM flags managed in software:
143 * RO: Read only. Never set PTE_D on this page, and don't
144 * listen to requests to write to it.
145 * W: Wired. ???
146 * MANAGED:Managed. This PTE maps a managed page.
147 *
148 * These bits should not be written into the TLB, so must first be masked out
149 * explicitly in C, or using CLEAR_PTE_SWBITS() in assembly.
150 */
151 #define PTE_RO ((pt_entry_t)0x01 << TLBLO_SWBITS_SHIFT)
152 #define PTE_W ((pt_entry_t)0x02 << TLBLO_SWBITS_SHIFT)
153 #define PTE_MANAGED ((pt_entry_t)0x04 << TLBLO_SWBITS_SHIFT)
154
155 /*
156 * PTE management functions for bits defined above.
157 */
158 #define pte_clear(pte, bit) (*(pte) &= ~(bit))
159 #define pte_set(pte, bit) (*(pte) |= (bit))
160 #define pte_test(pte, bit) ((*(pte) & (bit)) == (bit))
161
162 /* Assembly support for PTE access*/
163 #ifdef LOCORE
164 #if defined(__mips_n64) || defined(__mips_n32) /* PHYSADDR_64_BIT */
165 #define PTESHIFT 3
166 #define PTE2MASK 0xff0 /* for the 2-page lo0/lo1 */
167 #define PTEMASK 0xff8
168 #define PTESIZE 8
169 #define PTE_L ld
170 #define PTE_MTC0 dmtc0
171 #define CLEAR_PTE_SWBITS(pr)
172 #else
173 #define PTESHIFT 2
174 #define PTE2MASK 0xff8 /* for the 2-page lo0/lo1 */
175 #define PTEMASK 0xffc
176 #define PTESIZE 4
177 #define PTE_L lw
178 #define PTE_MTC0 mtc0
179 #define CLEAR_PTE_SWBITS(r) LONG_SLL r, TLBLO_SWBITS_CLEAR_SHIFT; LONG_SRL r, TLBLO_SWBITS_CLEAR_SHIFT /* remove swbits */
180 #endif /* defined(__mips_n64) || defined(__mips_n32) */
181
182 #if defined(__mips_n64)
183 #define PTRSHIFT 3
184 #define PDEPTRMASK 0xff8
185 #else
186 #define PTRSHIFT 2
187 #define PDEPTRMASK 0xffc
188 #endif
189
190 #endif /* LOCORE */
191 #endif /* !_MACHINE_PTE_H_ */
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