pte.h revision 1.1.2.2
1 1.1.2.2 bouyer /* $NetBSD: pte.h,v 1.1.2.2 2001/04/21 17:54:53 bouyer Exp $ */ 2 1.1.2.2 bouyer 3 1.1.2.2 bouyer /*- 4 1.1.2.2 bouyer * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 1.1.2.2 bouyer * All rights reserved. 6 1.1.2.2 bouyer * 7 1.1.2.2 bouyer * Redistribution and use in source and binary forms, with or without 8 1.1.2.2 bouyer * modification, are permitted provided that the following conditions 9 1.1.2.2 bouyer * are met: 10 1.1.2.2 bouyer * 1. Redistributions of source code must retain the above copyright 11 1.1.2.2 bouyer * notice, this list of conditions and the following disclaimer. 12 1.1.2.2 bouyer * 2. Redistributions in binary form must reproduce the above copyright 13 1.1.2.2 bouyer * notice, this list of conditions and the following disclaimer in the 14 1.1.2.2 bouyer * documentation and/or other materials provided with the distribution. 15 1.1.2.2 bouyer * 3. All advertising materials mentioning features or use of this software 16 1.1.2.2 bouyer * must display the following acknowledgement: 17 1.1.2.2 bouyer * This product includes software developed by the NetBSD 18 1.1.2.2 bouyer * Foundation, Inc. and its contributors. 19 1.1.2.2 bouyer * 4. Neither the name of The NetBSD Foundation nor the names of its 20 1.1.2.2 bouyer * contributors may be used to endorse or promote products derived 21 1.1.2.2 bouyer * from this software without specific prior written permission. 22 1.1.2.2 bouyer * 23 1.1.2.2 bouyer * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 24 1.1.2.2 bouyer * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 1.1.2.2 bouyer * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 1.1.2.2 bouyer * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 27 1.1.2.2 bouyer * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 1.1.2.2 bouyer * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 1.1.2.2 bouyer * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 1.1.2.2 bouyer * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 1.1.2.2 bouyer * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 1.1.2.2 bouyer * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 1.1.2.2 bouyer * POSSIBILITY OF SUCH DAMAGE. 34 1.1.2.2 bouyer */ 35 1.1.2.2 bouyer 36 1.1.2.2 bouyer #ifndef _MACHINE_PTE_H 37 1.1.2.2 bouyer #define _MACHINE_PTE_H 38 1.1.2.2 bouyer 39 1.1.2.2 bouyer #define NCONTEXT 8 40 1.1.2.2 bouyer #define NPMEG 256 41 1.1.2.2 bouyer #define SEGINV (NPMEG-1) 42 1.1.2.2 bouyer #define NPAGSEG 16 43 1.1.2.2 bouyer #define NSEGMAP 512 44 1.1.2.2 bouyer 45 1.1.2.2 bouyer /* 46 1.1.2.2 bouyer * In our zeal to use the sun3 pmap with as few changes as possible, 47 1.1.2.2 bouyer * we pretend that sun2 page table entries work more like their sun3 48 1.1.2.2 bouyer * counterparts. Namely, we pretend that they simply have PG_WRITE 49 1.1.2.2 bouyer * and PG_SYSTEM bits, and we use get_pte and set_pte to translate 50 1.1.2.2 bouyer * entries between the two styles. 51 1.1.2.2 bouyer * 52 1.1.2.2 bouyer * All known valid protections in a real sun2 PTE are given in 53 1.1.2.2 bouyer * (disabled) defines below, and are displayed as bitmaps here: 54 1.1.2.2 bouyer * 55 1.1.2.2 bouyer * 3 2 2 2 2 56 1.1.2.2 bouyer * 0 9 8 7 6 meaning 57 1.1.2.2 bouyer * ------------------- 58 1.1.2.2 bouyer * 1 1 1 0 0 PG_KW => a read/write kernel-only page. 59 1.1.2.2 bouyer * 1 0 1 0 0 PG_KR => a read-only kernel-only page. 60 1.1.2.2 bouyer * 1 1 1 1 1 PG_UW => a read/write kernel/user page. 61 1.1.2.2 bouyer * 1 0 1 1 0 PG_URKR => a read-only kernel/user page. 62 1.1.2.2 bouyer * 63 1.1.2.2 bouyer * The sun3 PTE protections we want to emulate are: 64 1.1.2.2 bouyer * 65 1.1.2.2 bouyer * PG_SYSTEM | PG_WRITE => a read/write kernel-only page. 66 1.1.2.2 bouyer * PG_SYSTEM => a read-only kernel-only page. 67 1.1.2.2 bouyer * PG_WRITE => a read/write kernel/user page. 68 1.1.2.2 bouyer * => a read-only kernel/user page. 69 1.1.2.2 bouyer * 70 1.1.2.2 bouyer * We want to assign values to PG_SYSTEM and PG_WRITE, and 71 1.1.2.2 bouyer * craft get_pte and set_pte to do a translation from and to the real 72 1.1.2.2 bouyer * hardware protections. 73 1.1.2.2 bouyer * 74 1.1.2.2 bouyer * We begin by noting that bits 30 and 28 are set in all known valid 75 1.1.2.2 bouyer * sun2 protections. Since we assume that the kernel can always read 76 1.1.2.2 bouyer * all pages in the system, we might as well call one of them the 77 1.1.2.2 bouyer * "kernel readable" bit, and say that the other is just always on. 78 1.1.2.2 bouyer * We deem bit 30 the "kernel readable" bit. There is some evidence 79 1.1.2.2 bouyer * that bit 28 may mean "not a device" (the PROM makes PTEs for its 80 1.1.2.2 bouyer * device mappings with bit 28 clear), but I'm not sure enough about 81 1.1.2.2 bouyer * this to do anything about it. So, set_pte will always set these 82 1.1.2.2 bouyer * bits when it loads a valid PTE, and get_pte will always clear them 83 1.1.2.2 bouyer * when it unloads a valid PTE. 84 1.1.2.2 bouyer * 85 1.1.2.2 bouyer * Bit 25, which SunOS calles the "fill on demand" bit, also needs 86 1.1.2.2 bouyer * to be set on all valid PTEs. Dunno any more about this bit. 87 1.1.2.2 bouyer * 88 1.1.2.2 bouyer * Next, we see that bit 27 is set for all pages the user can access, 89 1.1.2.2 bouyer * and clear otherwise. This bit has the opposite meaning of the sun3 90 1.1.2.2 bouyer * PG_SYSTEM bit, but that's OK - we will just define PG_SYSTEM to be 91 1.1.2.2 bouyer * bit 27, and set_pte and get_pte will invert it when loading or 92 1.1.2.2 bouyer * unloading a valid PTE. 93 1.1.2.2 bouyer * 94 1.1.2.2 bouyer * Bit 29 is set for all pages the kernel can write to. We define 95 1.1.2.2 bouyer * PG_WRITE to be bit 29. No inverting is done. 96 1.1.2.2 bouyer * 97 1.1.2.2 bouyer * That leaves us to take care of bit 26. This bit, and bit 27, need 98 1.1.2.2 bouyer * to be set for all pages the user can write to. On the sun3, all 99 1.1.2.2 bouyer * user-accessible pages that the kernel can write to, the user can 100 1.1.2.2 bouyer * also write to. We can use this fact to make set_pte set bit 26 iff 101 1.1.2.2 bouyer * the kernel can write to the page (PG_WRITE is set), and the user 102 1.1.2.2 bouyer * can also access the page (bit 27 is set, i.e., PG_SYSTEM was clear 103 1.1.2.2 bouyer * before set_pte inverted it). 104 1.1.2.2 bouyer * 105 1.1.2.2 bouyer * This is what makes set_pte tricky. It begins by clearing bit 26 106 1.1.2.2 bouyer * (this is paranoia, if all is working well, this bit should never be 107 1.1.2.2 bouyer * set in our pseudo-sun3 PTEs). It then flips PG_SYSTEM to become 108 1.1.2.2 bouyer * the user-accessible bit. Lastly, as the tricky part, it sets bits 109 1.1.2.2 bouyer * 30 and 28, *and* sets bit 26 by shifting the expression (pte & 110 1.1.2.2 bouyer * PG_WRITE) right by two to move the resulting "single bit" into the 111 1.1.2.2 bouyer * bit 27 position, ANDing that with bit 27 in the PTE (the 112 1.1.2.2 bouyer * user-accessible bit), shifting that right once more to line up with 113 1.1.2.2 bouyer * the target bit 26 in the PTE, and ORing it in. This will result in 114 1.1.2.2 bouyer * bit 26 being set if the pseudo-sun3 protection was simply PG_WRITE. 115 1.1.2.2 bouyer * 116 1.1.2.2 bouyer * This could be expressed with if .. else.. logic, but the bit 117 1.1.2.2 bouyer * shifts should compile into something that needs no branching. 118 1.1.2.2 bouyer * 119 1.1.2.2 bouyer * get_pte's job is easier. All it has to do is clear the always-set 120 1.1.2.2 bouyer * bits 30, 28, and 25, *and* clear bit 26, and flip PG_SYSTEM. It can 121 1.1.2.2 bouyer * clear bit 26 because the value that was there can always be derived 122 1.1.2.2 bouyer * from the resulting pseudo-sun3 PG_SYSTEM and PG_WRITE combination. 123 1.1.2.2 bouyer * 124 1.1.2.2 bouyer * And that's how we reuse the sun3 pmap. 125 1.1.2.2 bouyer */ 126 1.1.2.2 bouyer #define PG_VALID 0x80000000 127 1.1.2.2 bouyer #define PG_WRITE 0x20000000 128 1.1.2.2 bouyer #define PG_NC 0x00000000 129 1.1.2.2 bouyer #define PG_SYSTEM 0x08000000 130 1.1.2.2 bouyer #if 0 131 1.1.2.2 bouyer #define PG_KW 0x70000000 132 1.1.2.2 bouyer #define PG_KR 0x50000000 133 1.1.2.2 bouyer #define PG_UW 0x7C000000 134 1.1.2.2 bouyer #define PG_URKR 0x58000000 135 1.1.2.2 bouyer #endif 136 1.1.2.2 bouyer #define PG_TYPE 0x00C00000 137 1.1.2.2 bouyer #define PG_REF 0x00200000 138 1.1.2.2 bouyer #define PG_MOD 0x00100000 139 1.1.2.2 bouyer 140 1.1.2.2 bouyer #define PG_SPECIAL (PG_VALID|PG_WRITE|PG_SYSTEM|PG_NC|PG_REF|PG_MOD) 141 1.1.2.2 bouyer #define PG_PERM (PG_VALID|PG_WRITE|PG_SYSTEM|PG_NC) 142 1.1.2.2 bouyer #define PG_MODREF (PG_REF|PG_MOD) 143 1.1.2.2 bouyer #define PG_FRAME 0x00000FFF 144 1.1.2.2 bouyer 145 1.1.2.2 bouyer #define PG_MOD_SHIFT 20 146 1.1.2.2 bouyer 147 1.1.2.2 bouyer #define OBMEM 0 148 1.1.2.2 bouyer #define OBIO 1 149 1.1.2.2 bouyer #define MBMEM 2 /* on the 2/120, VME_D16 on the 2/50 */ 150 1.1.2.2 bouyer #define VME_D16 2 151 1.1.2.2 bouyer #define MBIO 3 /* on the 2/120, ??? on the 2/50 */ 152 1.1.2.2 bouyer #define PG_TYPE_SHIFT 22 153 1.1.2.2 bouyer 154 1.1.2.2 bouyer #define PG_INVAL 0x0 155 1.1.2.2 bouyer 156 1.1.2.2 bouyer #define MAKE_PGTYPE(x) ((x) << PG_TYPE_SHIFT) 157 1.1.2.2 bouyer #define PG_PFNUM(pte) (pte & PG_FRAME) 158 1.1.2.2 bouyer #define PG_PA(pte) (PG_PFNUM(pte) << PGSHIFT) 159 1.1.2.2 bouyer 160 1.1.2.2 bouyer #define PGT_MASK MAKE_PGTYPE(3) 161 1.1.2.2 bouyer #define PGT_OBMEM MAKE_PGTYPE(OBMEM) /* onboard memory */ 162 1.1.2.2 bouyer #define PGT_OBIO MAKE_PGTYPE(OBIO) /* onboard I/O */ 163 1.1.2.2 bouyer #define PGT_MBMEM MAKE_PGTYPE(MBMEM) /* Multibus memory on the 2/120, VME_D16 on the 2/50 */ 164 1.1.2.2 bouyer #define PGT_VME_D16 MAKE_PGTYPE(VME_D16) /* VMEbus 16-bit data */ 165 1.1.2.2 bouyer #define PGT_MBIO MAKE_PGTYPE(MBIO) /* Multibus I/O on the 2/120, ??? on the 2/50 */ 166 1.1.2.2 bouyer 167 1.1.2.2 bouyer #define VA_SEGNUM(x) ((u_int)(x) >> SEGSHIFT) 168 1.1.2.2 bouyer 169 1.1.2.2 bouyer #define VA_PTE_NUM_SHIFT PGSHIFT 170 1.1.2.2 bouyer #define VA_PTE_NUM_MASK (((1 << SEGSHIFT) - 1) ^ ((1 << PGSHIFT) - 1)) 171 1.1.2.2 bouyer #define VA_PTE_NUM(va) ((va & VA_PTE_NUM_MASK) >> VA_PTE_NUM_SHIFT) 172 1.1.2.2 bouyer 173 1.1.2.2 bouyer #define PA_PGNUM(pa) ((unsigned)pa >> PGSHIFT) 174 1.1.2.2 bouyer 175 1.1.2.2 bouyer #if defined(_KERNEL) || defined(_STANDALONE) 176 1.1.2.2 bouyer u_int get_pte __P((vm_offset_t va)); 177 1.1.2.2 bouyer void set_pte __P((vm_offset_t va, u_int pte)); 178 1.1.2.2 bouyer #endif /* _KERNEL */ 179 1.1.2.2 bouyer 180 1.1.2.2 bouyer #endif /* _MACHINE_PTE_H */ 181
Indexes created Tue Oct 21 16:10:11 GMT 2025