1 /* 2 * Definitions for use by exception code on Book3-E 3 * 4 * Copyright (C) 2008 Ben. Herrenschmidt (benh@kernel.crashing.org), IBM Corp. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 #ifndef _ASM_POWERPC_EXCEPTION_64E_H 12 #define _ASM_POWERPC_EXCEPTION_64E_H 13 14 /* 15 * SPRGs usage an other considerations... 16 * 17 * Since TLB miss and other standard exceptions can be interrupted by 18 * critical exceptions which can themselves be interrupted by machine 19 * checks, and since the two later can themselves cause a TLB miss when 20 * hitting the linear mapping for the kernel stacks, we need to be a bit 21 * creative on how we use SPRGs. 22 * 23 * The base idea is that we have one SRPG reserved for critical and one 24 * for machine check interrupts. Those are used to save a GPR that can 25 * then be used to get the PACA, and store as much context as we need 26 * to save in there. That includes saving the SPRGs used by the TLB miss 27 * handler for linear mapping misses and the associated SRR0/1 due to 28 * the above re-entrancy issue. 29 * 30 * So here's the current usage pattern. It's done regardless of which 31 * SPRGs are user-readable though, thus we might have to change some of 32 * this later. In order to do that more easily, we use special constants 33 * for naming them 34 * 35 * WARNING: Some of these SPRGs are user readable. We need to do something 36 * about it as some point by making sure they can't be used to leak kernel 37 * critical data 38 */ 39 40 41 /* We are out of SPRGs so we save some things in the PACA. The normal 42 * exception frame is smaller than the CRIT or MC one though 43 */ 44 #define EX_R1 (0 * 8) 45 #define EX_CR (1 * 8) 46 #define EX_R10 (2 * 8) 47 #define EX_R11 (3 * 8) 48 #define EX_R14 (4 * 8) 49 #define EX_R15 (5 * 8) 50 51 /* The TLB miss exception uses different slots */ 52 53 #define EX_TLB_R10 ( 0 * 8) 54 #define EX_TLB_R11 ( 1 * 8) 55 #define EX_TLB_R12 ( 2 * 8) 56 #define EX_TLB_R13 ( 3 * 8) 57 #define EX_TLB_R14 ( 4 * 8) 58 #define EX_TLB_R15 ( 5 * 8) 59 #define EX_TLB_R16 ( 6 * 8) 60 #define EX_TLB_CR ( 7 * 8) 61 #define EX_TLB_DEAR ( 8 * 8) /* Level 0 and 2 only */ 62 #define EX_TLB_ESR ( 9 * 8) /* Level 0 and 2 only */ 63 #define EX_TLB_SRR0 (10 * 8) 64 #define EX_TLB_SRR1 (11 * 8) 65 #define EX_TLB_MMUCR0 (12 * 8) /* Level 0 */ 66 #define EX_TLB_MAS1 (12 * 8) /* Level 0 */ 67 #define EX_TLB_MAS2 (13 * 8) /* Level 0 */ 68 #ifdef CONFIG_BOOK3E_MMU_TLB_STATS 69 #define EX_TLB_R8 (14 * 8) 70 #define EX_TLB_R9 (15 * 8) 71 #define EX_TLB_LR (16 * 8) 72 #define EX_TLB_SIZE (17 * 8) 73 #else 74 #define EX_TLB_SIZE (14 * 8) 75 #endif 76 77 #define START_EXCEPTION(label) \ 78 .globl exc_##label##_book3e; \ 79 exc_##label##_book3e: 80 81 /* TLB miss exception prolog 82 * 83 * This prolog handles re-entrancy (up to 3 levels supported in the PACA 84 * though we currently don't test for overflow). It provides you with a 85 * re-entrancy safe working space of r10...r16 and CR with r12 being used 86 * as the exception area pointer in the PACA for that level of re-entrancy 87 * and r13 containing the PACA pointer. 88 * 89 * SRR0 and SRR1 are saved, but DEAR and ESR are not, since they don't apply 90 * as-is for instruction exceptions. It's up to the actual exception code 91 * to save them as well if required. 92 */ 93 #define TLB_MISS_PROLOG \ 94 mtspr SPRN_SPRG_TLB_SCRATCH,r12; \ 95 mfspr r12,SPRN_SPRG_TLB_EXFRAME; \ 96 std r10,EX_TLB_R10(r12); \ 97 mfcr r10; \ 98 std r11,EX_TLB_R11(r12); \ 99 mfspr r11,SPRN_SPRG_TLB_SCRATCH; \ 100 std r13,EX_TLB_R13(r12); \ 101 mfspr r13,SPRN_SPRG_PACA; \ 102 std r14,EX_TLB_R14(r12); \ 103 addi r14,r12,EX_TLB_SIZE; \ 104 std r15,EX_TLB_R15(r12); \ 105 mfspr r15,SPRN_SRR1; \ 106 std r16,EX_TLB_R16(r12); \ 107 mfspr r16,SPRN_SRR0; \ 108 std r10,EX_TLB_CR(r12); \ 109 std r11,EX_TLB_R12(r12); \ 110 mtspr SPRN_SPRG_TLB_EXFRAME,r14; \ 111 std r15,EX_TLB_SRR1(r12); \ 112 std r16,EX_TLB_SRR0(r12); \ 113 TLB_MISS_PROLOG_STATS 114 115 /* And these are the matching epilogs that restores things 116 * 117 * There are 3 epilogs: 118 * 119 * - SUCCESS : Unwinds one level 120 * - ERROR : restore from level 0 and reset 121 * - ERROR_SPECIAL : restore from current level and reset 122 * 123 * Normal errors use ERROR, that is, they restore the initial fault context 124 * and trigger a fault. However, there is a special case for linear mapping 125 * errors. Those should basically never happen, but if they do happen, we 126 * want the error to point out the context that did that linear mapping 127 * fault, not the initial level 0 (basically, we got a bogus PGF or something 128 * like that). For userland errors on the linear mapping, there is no 129 * difference since those are always level 0 anyway 130 */ 131 132 #define TLB_MISS_RESTORE(freg) \ 133 ld r14,EX_TLB_CR(r12); \ 134 ld r10,EX_TLB_R10(r12); \ 135 ld r15,EX_TLB_SRR0(r12); \ 136 ld r16,EX_TLB_SRR1(r12); \ 137 mtspr SPRN_SPRG_TLB_EXFRAME,freg; \ 138 ld r11,EX_TLB_R11(r12); \ 139 mtcr r14; \ 140 ld r13,EX_TLB_R13(r12); \ 141 ld r14,EX_TLB_R14(r12); \ 142 mtspr SPRN_SRR0,r15; \ 143 ld r15,EX_TLB_R15(r12); \ 144 mtspr SPRN_SRR1,r16; \ 145 TLB_MISS_RESTORE_STATS \ 146 ld r16,EX_TLB_R16(r12); \ 147 ld r12,EX_TLB_R12(r12); \ 148 149 #define TLB_MISS_EPILOG_SUCCESS \ 150 TLB_MISS_RESTORE(r12) 151 152 #define TLB_MISS_EPILOG_ERROR \ 153 addi r12,r13,PACA_EXTLB; \ 154 TLB_MISS_RESTORE(r12) 155 156 #define TLB_MISS_EPILOG_ERROR_SPECIAL \ 157 addi r11,r13,PACA_EXTLB; \ 158 TLB_MISS_RESTORE(r11) 159 160 #ifdef CONFIG_BOOK3E_MMU_TLB_STATS 161 #define TLB_MISS_PROLOG_STATS \ 162 mflr r10; \ 163 std r8,EX_TLB_R8(r12); \ 164 std r9,EX_TLB_R9(r12); \ 165 std r10,EX_TLB_LR(r12); 166 #define TLB_MISS_RESTORE_STATS \ 167 ld r16,EX_TLB_LR(r12); \ 168 ld r9,EX_TLB_R9(r12); \ 169 ld r8,EX_TLB_R8(r12); \ 170 mtlr r16; 171 #define TLB_MISS_STATS_D(name) \ 172 addi r9,r13,MMSTAT_DSTATS+name; \ 173 bl .tlb_stat_inc; 174 #define TLB_MISS_STATS_I(name) \ 175 addi r9,r13,MMSTAT_ISTATS+name; \ 176 bl .tlb_stat_inc; 177 #define TLB_MISS_STATS_X(name) \ 178 ld r8,PACA_EXTLB+EX_TLB_ESR(r13); \ 179 cmpdi cr2,r8,-1; \ 180 beq cr2,61f; \ 181 addi r9,r13,MMSTAT_DSTATS+name; \ 182 b 62f; \ 183 61: addi r9,r13,MMSTAT_ISTATS+name; \ 184 62: bl .tlb_stat_inc; 185 #define TLB_MISS_STATS_SAVE_INFO \ 186 std r14,EX_TLB_ESR(r12); /* save ESR */ \ 187 188 189 #else 190 #define TLB_MISS_PROLOG_STATS 191 #define TLB_MISS_RESTORE_STATS 192 #define TLB_MISS_STATS_D(name) 193 #define TLB_MISS_STATS_I(name) 194 #define TLB_MISS_STATS_X(name) 195 #define TLB_MISS_STATS_Y(name) 196 #define TLB_MISS_STATS_SAVE_INFO 197 #endif 198 199 #define SET_IVOR(vector_number, vector_offset) \ 200 li r3,vector_offset@l; \ 201 ori r3,r3,interrupt_base_book3e@l; \ 202 mtspr SPRN_IVOR##vector_number,r3; 203 204 #endif /* _ASM_POWERPC_EXCEPTION_64E_H */ 205 206