1 /* 2 * Switch a MMU context. 3 * 4 * This file is subject to the terms and conditions of the GNU General Public 5 * License. See the file "COPYING" in the main directory of this archive 6 * for more details. 7 * 8 * Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle 9 * Copyright (C) 1999 Silicon Graphics, Inc. 10 */ 11 #ifndef _ASM_MMU_CONTEXT_H 12 #define _ASM_MMU_CONTEXT_H 13 14 #include <linux/errno.h> 15 #include <linux/sched.h> 16 #include <linux/smp.h> 17 #include <linux/slab.h> 18 #include <asm/cacheflush.h> 19 #include <asm/hazards.h> 20 #include <asm/tlbflush.h> 21 #ifdef CONFIG_MIPS_MT_SMTC 22 #include <asm/mipsmtregs.h> 23 #include <asm/smtc.h> 24 #endif /* SMTC */ 25 #include <asm-generic/mm_hooks.h> 26 27 #ifdef CONFIG_MIPS_PGD_C0_CONTEXT 28 29 #define TLBMISS_HANDLER_SETUP_PGD(pgd) \ 30 tlbmiss_handler_setup_pgd((unsigned long)(pgd)) 31 32 extern void tlbmiss_handler_setup_pgd(unsigned long pgd); 33 34 #define TLBMISS_HANDLER_SETUP() \ 35 do { \ 36 TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir); \ 37 write_c0_xcontext((unsigned long) smp_processor_id() << 51); \ 38 } while (0) 39 40 41 static inline unsigned long get_current_pgd(void) 42 { 43 return PHYS_TO_XKSEG_CACHED((read_c0_context() >> 11) & ~0xfffUL); 44 } 45 46 #else /* CONFIG_MIPS_PGD_C0_CONTEXT: using pgd_current*/ 47 48 /* 49 * For the fast tlb miss handlers, we keep a per cpu array of pointers 50 * to the current pgd for each processor. Also, the proc. id is stuffed 51 * into the context register. 52 */ 53 extern unsigned long pgd_current[]; 54 55 #define TLBMISS_HANDLER_SETUP_PGD(pgd) \ 56 pgd_current[smp_processor_id()] = (unsigned long)(pgd) 57 58 #ifdef CONFIG_32BIT 59 #define TLBMISS_HANDLER_SETUP() \ 60 write_c0_context((unsigned long) smp_processor_id() << 25); \ 61 back_to_back_c0_hazard(); \ 62 TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir) 63 #endif 64 #ifdef CONFIG_64BIT 65 #define TLBMISS_HANDLER_SETUP() \ 66 write_c0_context((unsigned long) smp_processor_id() << 26); \ 67 back_to_back_c0_hazard(); \ 68 TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir) 69 #endif 70 #endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/ 71 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) 72 73 #define ASID_INC 0x40 74 #define ASID_MASK 0xfc0 75 76 #elif defined(CONFIG_CPU_R8000) 77 78 #define ASID_INC 0x10 79 #define ASID_MASK 0xff0 80 81 #elif defined(CONFIG_CPU_RM9000) 82 83 #define ASID_INC 0x1 84 #define ASID_MASK 0xfff 85 86 /* SMTC/34K debug hack - but maybe we'll keep it */ 87 #elif defined(CONFIG_MIPS_MT_SMTC) 88 89 #define ASID_INC 0x1 90 extern unsigned long smtc_asid_mask; 91 #define ASID_MASK (smtc_asid_mask) 92 #define HW_ASID_MASK 0xff 93 /* End SMTC/34K debug hack */ 94 #else /* FIXME: not correct for R6000 */ 95 96 #define ASID_INC 0x1 97 #define ASID_MASK 0xff 98 99 #endif 100 101 #define cpu_context(cpu, mm) ((mm)->context.asid[cpu]) 102 #define cpu_asid(cpu, mm) (cpu_context((cpu), (mm)) & ASID_MASK) 103 #define asid_cache(cpu) (cpu_data[cpu].asid_cache) 104 105 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) 106 { 107 } 108 109 /* 110 * All unused by hardware upper bits will be considered 111 * as a software asid extension. 112 */ 113 #define ASID_VERSION_MASK ((unsigned long)~(ASID_MASK|(ASID_MASK-1))) 114 #define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1) 115 116 #ifndef CONFIG_MIPS_MT_SMTC 117 /* Normal, classic MIPS get_new_mmu_context */ 118 static inline void 119 get_new_mmu_context(struct mm_struct *mm, unsigned long cpu) 120 { 121 unsigned long asid = asid_cache(cpu); 122 123 if (! ((asid += ASID_INC) & ASID_MASK) ) { 124 if (cpu_has_vtag_icache) 125 flush_icache_all(); 126 local_flush_tlb_all(); /* start new asid cycle */ 127 if (!asid) /* fix version if needed */ 128 asid = ASID_FIRST_VERSION; 129 } 130 cpu_context(cpu, mm) = asid_cache(cpu) = asid; 131 } 132 133 #else /* CONFIG_MIPS_MT_SMTC */ 134 135 #define get_new_mmu_context(mm, cpu) smtc_get_new_mmu_context((mm), (cpu)) 136 137 #endif /* CONFIG_MIPS_MT_SMTC */ 138 139 /* 140 * Initialize the context related info for a new mm_struct 141 * instance. 142 */ 143 static inline int 144 init_new_context(struct task_struct *tsk, struct mm_struct *mm) 145 { 146 int i; 147 148 for_each_online_cpu(i) 149 cpu_context(i, mm) = 0; 150 151 return 0; 152 } 153 154 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, 155 struct task_struct *tsk) 156 { 157 unsigned int cpu = smp_processor_id(); 158 unsigned long flags; 159 #ifdef CONFIG_MIPS_MT_SMTC 160 unsigned long oldasid; 161 unsigned long mtflags; 162 int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id; 163 local_irq_save(flags); 164 mtflags = dvpe(); 165 #else /* Not SMTC */ 166 local_irq_save(flags); 167 #endif /* CONFIG_MIPS_MT_SMTC */ 168 169 /* Check if our ASID is of an older version and thus invalid */ 170 if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & ASID_VERSION_MASK) 171 get_new_mmu_context(next, cpu); 172 #ifdef CONFIG_MIPS_MT_SMTC 173 /* 174 * If the EntryHi ASID being replaced happens to be 175 * the value flagged at ASID recycling time as having 176 * an extended life, clear the bit showing it being 177 * in use by this "CPU", and if that's the last bit, 178 * free up the ASID value for use and flush any old 179 * instances of it from the TLB. 180 */ 181 oldasid = (read_c0_entryhi() & ASID_MASK); 182 if(smtc_live_asid[mytlb][oldasid]) { 183 smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu); 184 if(smtc_live_asid[mytlb][oldasid] == 0) 185 smtc_flush_tlb_asid(oldasid); 186 } 187 /* 188 * Tread softly on EntryHi, and so long as we support 189 * having ASID_MASK smaller than the hardware maximum, 190 * make sure no "soft" bits become "hard"... 191 */ 192 write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) | 193 cpu_asid(cpu, next)); 194 ehb(); /* Make sure it propagates to TCStatus */ 195 evpe(mtflags); 196 #else 197 write_c0_entryhi(cpu_asid(cpu, next)); 198 #endif /* CONFIG_MIPS_MT_SMTC */ 199 TLBMISS_HANDLER_SETUP_PGD(next->pgd); 200 201 /* 202 * Mark current->active_mm as not "active" anymore. 203 * We don't want to mislead possible IPI tlb flush routines. 204 */ 205 cpumask_clear_cpu(cpu, mm_cpumask(prev)); 206 cpumask_set_cpu(cpu, mm_cpumask(next)); 207 208 local_irq_restore(flags); 209 } 210 211 /* 212 * Destroy context related info for an mm_struct that is about 213 * to be put to rest. 214 */ 215 static inline void destroy_context(struct mm_struct *mm) 216 { 217 } 218 219 #define deactivate_mm(tsk, mm) do { } while (0) 220 221 /* 222 * After we have set current->mm to a new value, this activates 223 * the context for the new mm so we see the new mappings. 224 */ 225 static inline void 226 activate_mm(struct mm_struct *prev, struct mm_struct *next) 227 { 228 unsigned long flags; 229 unsigned int cpu = smp_processor_id(); 230 231 #ifdef CONFIG_MIPS_MT_SMTC 232 unsigned long oldasid; 233 unsigned long mtflags; 234 int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id; 235 #endif /* CONFIG_MIPS_MT_SMTC */ 236 237 local_irq_save(flags); 238 239 /* Unconditionally get a new ASID. */ 240 get_new_mmu_context(next, cpu); 241 242 #ifdef CONFIG_MIPS_MT_SMTC 243 /* See comments for similar code above */ 244 mtflags = dvpe(); 245 oldasid = read_c0_entryhi() & ASID_MASK; 246 if(smtc_live_asid[mytlb][oldasid]) { 247 smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu); 248 if(smtc_live_asid[mytlb][oldasid] == 0) 249 smtc_flush_tlb_asid(oldasid); 250 } 251 /* See comments for similar code above */ 252 write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) | 253 cpu_asid(cpu, next)); 254 ehb(); /* Make sure it propagates to TCStatus */ 255 evpe(mtflags); 256 #else 257 write_c0_entryhi(cpu_asid(cpu, next)); 258 #endif /* CONFIG_MIPS_MT_SMTC */ 259 TLBMISS_HANDLER_SETUP_PGD(next->pgd); 260 261 /* mark mmu ownership change */ 262 cpumask_clear_cpu(cpu, mm_cpumask(prev)); 263 cpumask_set_cpu(cpu, mm_cpumask(next)); 264 265 local_irq_restore(flags); 266 } 267 268 /* 269 * If mm is currently active_mm, we can't really drop it. Instead, 270 * we will get a new one for it. 271 */ 272 static inline void 273 drop_mmu_context(struct mm_struct *mm, unsigned cpu) 274 { 275 unsigned long flags; 276 #ifdef CONFIG_MIPS_MT_SMTC 277 unsigned long oldasid; 278 /* Can't use spinlock because called from TLB flush within DVPE */ 279 unsigned int prevvpe; 280 int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id; 281 #endif /* CONFIG_MIPS_MT_SMTC */ 282 283 local_irq_save(flags); 284 285 if (cpumask_test_cpu(cpu, mm_cpumask(mm))) { 286 get_new_mmu_context(mm, cpu); 287 #ifdef CONFIG_MIPS_MT_SMTC 288 /* See comments for similar code above */ 289 prevvpe = dvpe(); 290 oldasid = (read_c0_entryhi() & ASID_MASK); 291 if (smtc_live_asid[mytlb][oldasid]) { 292 smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu); 293 if(smtc_live_asid[mytlb][oldasid] == 0) 294 smtc_flush_tlb_asid(oldasid); 295 } 296 /* See comments for similar code above */ 297 write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) 298 | cpu_asid(cpu, mm)); 299 ehb(); /* Make sure it propagates to TCStatus */ 300 evpe(prevvpe); 301 #else /* not CONFIG_MIPS_MT_SMTC */ 302 write_c0_entryhi(cpu_asid(cpu, mm)); 303 #endif /* CONFIG_MIPS_MT_SMTC */ 304 } else { 305 /* will get a new context next time */ 306 #ifndef CONFIG_MIPS_MT_SMTC 307 cpu_context(cpu, mm) = 0; 308 #else /* SMTC */ 309 int i; 310 311 /* SMTC shares the TLB (and ASIDs) across VPEs */ 312 for_each_online_cpu(i) { 313 if((smtc_status & SMTC_TLB_SHARED) 314 || (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id)) 315 cpu_context(i, mm) = 0; 316 } 317 #endif /* CONFIG_MIPS_MT_SMTC */ 318 } 319 local_irq_restore(flags); 320 } 321 322 #endif /* _ASM_MMU_CONTEXT_H */ 323