1 /* $NetBSD: mmu_sh3.c,v 1.16 2025/07/15 22:15:03 andvar Exp $ */ 2 3 /*- 4 * Copyright (c) 2002 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by UCHIYAMA Yasushi. 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 __KERNEL_RCSID(0, "$NetBSD: mmu_sh3.c,v 1.16 2025/07/15 22:15:03 andvar Exp $"); 34 35 #include <sys/param.h> 36 37 #include <sh3/pte.h> 38 #include <sh3/mmu.h> 39 #include <sh3/mmu_sh3.h> 40 41 42 void 43 sh3_mmu_start(void) 44 { 45 46 /* Zero clear all TLB entries */ 47 sh3_tlb_invalidate_all(); 48 49 /* Set current ASID to 0 - kernel */ 50 sh_tlb_set_asid(0); 51 52 /* Flush TLB (TF) and enable address translation (AT) */ 53 _reg_write_4(SH3_MMUCR, SH3_MMUCR_TF | SH3_MMUCR_AT); 54 } 55 56 57 void 58 sh3_tlb_invalidate_all(void) 59 { 60 uint32_t idx, a; 61 int i, way; 62 63 for (i = 0; i < SH3_MMU_ENTRY; ++i) { 64 idx = i << SH3_MMU_VPN_SHIFT; 65 66 for (way = 0; way < SH3_MMU_WAY; ++way) { 67 a = idx | (way << SH3_MMU_WAY_SHIFT); 68 69 _reg_write_4(SH3_MMUAA | a, 0); 70 _reg_write_4(SH3_MMUDA | a, 0); 71 } 72 } 73 } 74 75 76 void 77 sh3_tlb_invalidate_asid(int asid) 78 { 79 uint32_t idx, aa; 80 int i, way; 81 82 for (i = 0; i < SH3_MMU_ENTRY; ++i) { 83 idx = i << SH3_MMU_VPN_SHIFT; 84 85 for (way = 0; way < SH3_MMU_WAY; ++way) { 86 aa = SH3_MMUAA | idx | (way << SH3_MMU_WAY_SHIFT); 87 88 if ((_reg_read_4(aa) & SH3_MMUAA_D_ASID_MASK) == asid) 89 _reg_write_4(aa, 0); 90 } 91 } 92 } 93 94 95 void 96 sh3_tlb_invalidate_addr(int asid, vaddr_t va) 97 { 98 uint32_t match, idx, aa, entry; 99 int way; 100 101 /* What we are looking for in the address array */ 102 match = (va & SH3_MMUAA_D_VPN_MASK_4K) | asid; 103 104 /* Where in the address array this VA is located - bits [16:12] */ 105 idx = va & SH3_MMU_VPN_MASK; 106 107 /* Check each way - bits [9:8] */ 108 for (way = 0; way < SH3_MMU_WAY; ++way) { 109 aa = SH3_MMUAA | idx | (way << SH3_MMU_WAY_SHIFT); 110 111 entry = _reg_read_4(aa) 112 & (SH3_MMUAA_D_VPN_MASK_4K | SH3_MMUAA_D_ASID_MASK); 113 114 if (entry == match) { 115 _reg_write_4(aa, 0); 116 break; 117 } 118 } 119 } 120 121 122 void 123 sh3_tlb_update(int asid, vaddr_t va, uint32_t pte) 124 { 125 static unsigned int rc = 0; 126 127 uint32_t match, idx, a, entry; 128 uint32_t freea, matcha; 129 uint32_t newa, newd; 130 int way; 131 int s; 132 133 KDASSERT(asid < 256 && (pte & ~PGOFSET) != 0 && va != 0); 134 135 136 if ((pte & PG_V) == 0) { 137 sh3_tlb_invalidate_addr(asid, va); 138 return; 139 } 140 141 142 /* 143 * Simple approach is to invalidate + ldtlb, but ldtlb uses 144 * MMUCR.RC to select the way to overwrite, and RC is only 145 * meaningful immediately after TLB exception, so ldtlb here 146 * would update some random way, e.g. a valid way even if 147 * there is an invalid way we could use instead. 148 * 149 * Nano-optimization: as invalidation needs to loop over 150 * ways anyway, just loop over all of them, noting if there's 151 * either an existing entry for this VA that we can update or 152 * an invalid way we can use. 153 */ 154 155 /* What we are looking for in the address array */ 156 match = (va & SH3_MMUAA_D_VPN_MASK_4K) | asid; 157 158 /* Where in the address array this VA is located - bits [16:12] */ 159 idx = va & SH3_MMU_VPN_MASK; 160 161 newa = match | SH3_MMU_D_VALID; 162 newd = pte & PG_HW_BITS; 163 164 matcha = freea = ~0; 165 166 167 s = splhigh(); 168 169 /* Check each way - bits [9:8] */ 170 for (way = 0; way < SH3_MMU_WAY; ++way) { 171 a = idx | (way << SH3_MMU_WAY_SHIFT); 172 173 entry = _reg_read_4(SH3_MMUAA | a); 174 175 if ((entry & SH3_MMU_D_VALID) == 0) 176 freea = a; 177 178 entry &= (SH3_MMUAA_D_VPN_MASK_4K | SH3_MMUAA_D_ASID_MASK); 179 if (entry == match) { 180 matcha = a; 181 break; 182 } 183 } 184 185 if ((int)matcha >= 0) /* there's an existing entry, update it */ 186 a = matcha; 187 else if ((int)freea >= 0) /* there's an invalid way, overwrite it */ 188 a = freea; 189 else { /* no match, all ways are valid */ 190 a = idx | (rc << SH3_MMU_WAY_SHIFT); 191 rc = (rc + 1) % SH3_MMU_WAY; 192 } 193 194 _reg_write_4(SH3_MMUAA | a, newa); 195 _reg_write_4(SH3_MMUDA | a, newd); 196 197 splx(s); 198 } 199
Indexes created Sat Sep 20 22:09:52 GMT 2025