| 1 | /*
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| 2 | * Copyright (c) 2006 Martin Decky
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | /** @addtogroup ppc32mm
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| 30 | * @{
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| 31 | */
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| 32 | /** @file
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| 33 | */
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| 34 |
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| 35 | #include <arch/mm/pht.h>
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| 36 | #include <arch/mm/tlb.h>
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| 37 | #include <interrupt.h>
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| 38 | #include <mm/as.h>
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| 39 | #include <mm/page.h>
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| 40 | #include <macros.h>
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| 41 | #include <typedefs.h>
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| 42 |
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| 43 | static unsigned int seed = 42;
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| 44 |
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| 45 | /** Try to find PTE for faulting address
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| 46 | *
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| 47 | * @param as Address space.
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| 48 | * @param badvaddr Faulting virtual address.
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| 49 | * @param access Access mode that caused the fault.
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| 50 | * @param istate Pointer to interrupted state.
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| 51 | * @param pfrc Pointer to variable where as_page_fault() return code
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| 52 | * will be stored.
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| 53 | *
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| 54 | * @return PTE on success, NULL otherwise.
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| 55 | *
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| 56 | */
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| 57 | static pte_t *find_mapping_and_check(as_t *as, uintptr_t badvaddr, int access,
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| 58 | istate_t *istate, int *pfrc)
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| 59 | {
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| 60 | /*
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| 61 | * Check if the mapping exists in page tables.
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| 62 | */
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| 63 | pte_t *pte = page_mapping_find(as, badvaddr, true);
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| 64 | if ((pte) && (pte->present)) {
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| 65 | /*
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| 66 | * Mapping found in page tables.
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| 67 | * Immediately succeed.
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| 68 | */
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| 69 | return pte;
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| 70 | } else {
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| 71 | /*
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| 72 | * Mapping not found in page tables.
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| 73 | * Resort to higher-level page fault handler.
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| 74 | */
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| 75 | int rc = as_page_fault(badvaddr, access, istate);
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| 76 | switch (rc) {
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| 77 | case AS_PF_OK:
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| 78 | /*
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| 79 | * The higher-level page fault handler succeeded,
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| 80 | * The mapping ought to be in place.
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| 81 | */
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| 82 | pte = page_mapping_find(as, badvaddr, true);
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| 83 | ASSERT((pte) && (pte->present));
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| 84 | *pfrc = 0;
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| 85 | return pte;
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| 86 | case AS_PF_DEFER:
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| 87 | *pfrc = rc;
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| 88 | return NULL;
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| 89 | case AS_PF_FAULT:
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| 90 | *pfrc = rc;
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| 91 | return NULL;
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| 92 | default:
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| 93 | panic("Unexpected rc (%d).", rc);
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| 94 | }
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| 95 | }
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| 96 | }
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| 97 |
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| 98 | static void pht_refill_fail(uintptr_t badvaddr, istate_t *istate)
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| 99 | {
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| 100 | fault_if_from_uspace(istate, "PHT Refill Exception on %p.",
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| 101 | (void *) badvaddr);
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| 102 | panic_memtrap(istate, PF_ACCESS_UNKNOWN, badvaddr,
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| 103 | "PHT Refill Exception.");
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| 104 | }
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| 105 |
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| 106 | static void pht_insert(const uintptr_t vaddr, const pte_t *pte)
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| 107 | {
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| 108 | uint32_t page = (vaddr >> 12) & 0xffff;
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| 109 | uint32_t api = (vaddr >> 22) & 0x3f;
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| 110 |
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| 111 | uint32_t vsid = sr_get(vaddr);
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| 112 | uint32_t sdr1 = sdr1_get();
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| 113 |
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| 114 | // FIXME: compute size of PHT exactly
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| 115 | phte_t *phte = (phte_t *) PA2KA(sdr1 & 0xffff0000);
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| 116 |
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| 117 | /* Primary hash (xor) */
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| 118 | uint32_t h = 0;
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| 119 | uint32_t hash = vsid ^ page;
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| 120 | uint32_t base = (hash & 0x3ff) << 3;
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| 121 | uint32_t i;
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| 122 | bool found = false;
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| 123 |
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| 124 | /* Find colliding PTE in PTEG */
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| 125 | for (i = 0; i < 8; i++) {
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| 126 | if ((phte[base + i].v)
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| 127 | && (phte[base + i].vsid == vsid)
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| 128 | && (phte[base + i].api == api)
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| 129 | && (phte[base + i].h == 0)) {
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| 130 | found = true;
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| 131 | break;
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| 132 | }
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| 133 | }
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| 134 |
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| 135 | if (!found) {
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| 136 | /* Find unused PTE in PTEG */
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| 137 | for (i = 0; i < 8; i++) {
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| 138 | if (!phte[base + i].v) {
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| 139 | found = true;
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| 140 | break;
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| 141 | }
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| 142 | }
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| 143 | }
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| 144 |
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| 145 | if (!found) {
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| 146 | /* Secondary hash (not) */
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| 147 | uint32_t base2 = (~hash & 0x3ff) << 3;
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| 148 |
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| 149 | /* Find colliding PTE in PTEG */
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| 150 | for (i = 0; i < 8; i++) {
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| 151 | if ((phte[base2 + i].v)
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| 152 | && (phte[base2 + i].vsid == vsid)
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| 153 | && (phte[base2 + i].api == api)
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| 154 | && (phte[base2 + i].h == 1)) {
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| 155 | found = true;
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| 156 | base = base2;
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| 157 | h = 1;
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| 158 | break;
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| 159 | }
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| 160 | }
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| 161 |
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| 162 | if (!found) {
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| 163 | /* Find unused PTE in PTEG */
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| 164 | for (i = 0; i < 8; i++) {
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| 165 | if (!phte[base2 + i].v) {
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| 166 | found = true;
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| 167 | base = base2;
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| 168 | h = 1;
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| 169 | break;
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| 170 | }
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| 171 | }
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| 172 | }
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| 173 |
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| 174 | if (!found)
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| 175 | i = RANDI(seed) % 8;
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| 176 | }
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| 177 |
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| 178 | phte[base + i].v = 1;
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| 179 | phte[base + i].vsid = vsid;
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| 180 | phte[base + i].h = h;
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| 181 | phte[base + i].api = api;
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| 182 | phte[base + i].rpn = pte->pfn;
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| 183 | phte[base + i].r = 0;
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| 184 | phte[base + i].c = 0;
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| 185 | phte[base + i].wimg = (pte->page_cache_disable ? WIMG_NO_CACHE : 0);
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| 186 | phte[base + i].pp = 2; // FIXME
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| 187 | }
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| 188 |
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| 189 | /** Process Instruction/Data Storage Exception
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| 190 | *
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| 191 | * @param n Exception vector number.
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| 192 | * @param istate Interrupted register context.
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| 193 | *
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| 194 | */
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| 195 | void pht_refill(unsigned int n, istate_t *istate)
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| 196 | {
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| 197 | uintptr_t badvaddr;
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| 198 |
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| 199 | if (n == VECTOR_DATA_STORAGE)
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| 200 | badvaddr = istate->dar;
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| 201 | else
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| 202 | badvaddr = istate->pc;
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| 203 |
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| 204 | int pfrc;
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| 205 | pte_t *pte = find_mapping_and_check(AS, badvaddr,
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| 206 | PF_ACCESS_READ /* FIXME */, istate, &pfrc);
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| 207 |
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| 208 | if (!pte) {
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| 209 | switch (pfrc) {
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| 210 | case AS_PF_FAULT:
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| 211 | pht_refill_fail(badvaddr, istate);
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| 212 | return;
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| 213 | case AS_PF_DEFER:
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| 214 | /*
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| 215 | * The page fault came during copy_from_uspace()
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| 216 | * or copy_to_uspace().
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| 217 | */
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| 218 | return;
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| 219 | default:
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| 220 | panic("Unexpected pfrc (%d).", pfrc);
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| 221 | }
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| 222 | }
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| 223 |
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| 224 | /* Record access to PTE */
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| 225 | pte->accessed = 1;
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| 226 | pht_insert(badvaddr, pte);
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| 227 | }
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| 228 |
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| 229 | void pht_invalidate(as_t *as, uintptr_t page, size_t pages)
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| 230 | {
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| 231 | uint32_t sdr1 = sdr1_get();
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| 232 |
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| 233 | // FIXME: compute size of PHT exactly
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| 234 | phte_t *phte = (phte_t *) PA2KA(sdr1 & 0xffff0000);
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| 235 |
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| 236 | // FIXME: this invalidates all PHT entries,
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| 237 | // which is an overkill, invalidate only
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| 238 | // selectively
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| 239 | for (size_t i = 0; i < 8192; i++) {
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| 240 | phte[i].v = 0;
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| 241 | }
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| 242 | }
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| 243 |
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| 244 | /** @}
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| 245 | */
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