arch/m68k/include/asm/mmu_context.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __M68K_MMU_CONTEXT_H
   3 #define __M68K_MMU_CONTEXT_H
   4
   5 #include <asm-generic/mm_hooks.h>
   6 #include <linux/mm_types.h>
   7
   8 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
   9 {
  10 }
  11
  12 #ifdef CONFIG_MMU
  13
  14 #if defined(CONFIG_COLDFIRE)
  15
  16 #include <asm/atomic.h>
  17 #include <asm/bitops.h>
  18 #include <asm/mcfmmu.h>
  19 #include <asm/mmu.h>
  20
  21 #define NO_CONTEXT              256
  22 #define LAST_CONTEXT            255
  23 #define FIRST_CONTEXT           1
  24
  25 extern unsigned long context_map[];
  26 extern mm_context_t next_mmu_context;
  27
  28 extern atomic_t nr_free_contexts;
  29 extern struct mm_struct *context_mm[LAST_CONTEXT+1];
  30 extern void steal_context(void);
  31
  32 static inline void get_mmu_context(struct mm_struct *mm)
  33 {
  34         mm_context_t ctx;
  35
  36         if (mm->context != NO_CONTEXT)
  37                 return;
  38         while (atomic_dec_and_test_lt(&nr_free_contexts)) {
  39                 atomic_inc(&nr_free_contexts);
  40                 steal_context();
  41         }
  42         ctx = next_mmu_context;
  43         while (test_and_set_bit(ctx, context_map)) {
  44                 ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
  45                 if (ctx > LAST_CONTEXT)
  46                         ctx = 0;
  47         }
  48         next_mmu_context = (ctx + 1) & LAST_CONTEXT;
  49         mm->context = ctx;
  50         context_mm[ctx] = mm;
  51 }
  52
  53 /*
  54  * Set up the context for a new address space.
  55  */
  56 #define init_new_context(tsk, mm)       (((mm)->context = NO_CONTEXT), 0)
  57
  58 /*
  59  * We're finished using the context for an address space.
  60  */
  61 static inline void destroy_context(struct mm_struct *mm)
  62 {
  63         if (mm->context != NO_CONTEXT) {
  64                 clear_bit(mm->context, context_map);
  65                 mm->context = NO_CONTEXT;
  66                 atomic_inc(&nr_free_contexts);
  67         }
  68 }
  69
  70 static inline void set_context(mm_context_t context, pgd_t *pgd)
  71 {
  72         __asm__ __volatile__ ("movec %0,%%asid" : : "d" (context));
  73 }
  74
  75 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  76         struct task_struct *tsk)
  77 {
  78         get_mmu_context(tsk->mm);
  79         set_context(tsk->mm->context, next->pgd);
  80 }
  81
  82 /*
  83  * After we have set current->mm to a new value, this activates
  84  * the context for the new mm so we see the new mappings.
  85  */
  86 static inline void activate_mm(struct mm_struct *active_mm,
  87         struct mm_struct *mm)
  88 {
  89         get_mmu_context(mm);
  90         set_context(mm->context, mm->pgd);
  91 }
  92
  93 #define deactivate_mm(tsk, mm) do { } while (0)
  94
  95 #define prepare_arch_switch(next) load_ksp_mmu(next)
  96
  97 static inline void load_ksp_mmu(struct task_struct *task)
  98 {
  99         unsigned long flags;
 100         struct mm_struct *mm;
 101         int asid;
 102         pgd_t *pgd;
 103         pmd_t *pmd;
 104         pte_t *pte;
 105         unsigned long mmuar;
 106
 107         local_irq_save(flags);
 108         mmuar = task->thread.ksp;
 109
 110         /* Search for a valid TLB entry, if one is found, don't remap */
 111         mmu_write(MMUAR, mmuar);
 112         mmu_write(MMUOR, MMUOR_STLB | MMUOR_ADR);
 113         if (mmu_read(MMUSR) & MMUSR_HIT)
 114                 goto end;
 115
 116         if (mmuar >= PAGE_OFFSET) {
 117                 mm = &init_mm;
 118         } else {
 119                 pr_info("load_ksp_mmu: non-kernel mm found: 0x%p\n", task->mm);
 120                 mm = task->mm;
 121         }
 122
 123         if (!mm)
 124                 goto bug;
 125
 126         pgd = pgd_offset(mm, mmuar);
 127         if (pgd_none(*pgd))
 128                 goto bug;
 129
 130         pmd = pmd_offset(pgd, mmuar);
 131         if (pmd_none(*pmd))
 132                 goto bug;
 133
 134         pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
 135                                      : pte_offset_map(pmd, mmuar);
 136         if (pte_none(*pte) || !pte_present(*pte))
 137                 goto bug;
 138
 139         set_pte(pte, pte_mkyoung(*pte));
 140         asid = mm->context & 0xff;
 141         if (!pte_dirty(*pte) && mmuar <= PAGE_OFFSET)
 142                 set_pte(pte, pte_wrprotect(*pte));
 143
 144         mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |
 145                 (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)
 146                 >> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);
 147
 148         mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
 149                 ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
 150
 151         mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
 152
 153         goto end;
 154
 155 bug:
 156         pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
 157 end:
 158         local_irq_restore(flags);
 159 }
 160
 161 #elif defined(CONFIG_SUN3)
 162 #include <asm/sun3mmu.h>
 163 #include <linux/sched.h>
 164
 165 extern unsigned long get_free_context(struct mm_struct *mm);
 166 extern void clear_context(unsigned long context);
 167
 168 /* set the context for a new task to unmapped */
 169 static inline int init_new_context(struct task_struct *tsk,
 170                                    struct mm_struct *mm)
 171 {
 172         mm->context = SUN3_INVALID_CONTEXT;
 173         return 0;
 174 }
 175
 176 /* find the context given to this process, and if it hasn't already
 177    got one, go get one for it. */
 178 static inline void get_mmu_context(struct mm_struct *mm)
 179 {
 180         if (mm->context == SUN3_INVALID_CONTEXT)
 181                 mm->context = get_free_context(mm);
 182 }
 183
 184 /* flush context if allocated... */
 185 static inline void destroy_context(struct mm_struct *mm)
 186 {
 187         if (mm->context != SUN3_INVALID_CONTEXT)
 188                 clear_context(mm->context);
 189 }
 190
 191 static inline void activate_context(struct mm_struct *mm)
 192 {
 193         get_mmu_context(mm);
 194         sun3_put_context(mm->context);
 195 }
 196
 197 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 198                              struct task_struct *tsk)
 199 {
 200         activate_context(tsk->mm);
 201 }
 202
 203 #define deactivate_mm(tsk, mm)  do { } while (0)
 204
 205 static inline void activate_mm(struct mm_struct *prev_mm,
 206                                struct mm_struct *next_mm)
 207 {
 208         activate_context(next_mm);
 209 }
 210
 211 #else
 212
 213 #include <asm/setup.h>
 214 #include <asm/page.h>
 215 #include <asm/pgalloc.h>
 216
 217 static inline int init_new_context(struct task_struct *tsk,
 218                                    struct mm_struct *mm)
 219 {
 220         mm->context = virt_to_phys(mm->pgd);
 221         return 0;
 222 }
 223
 224 #define destroy_context(mm)             do { } while(0)
 225
 226 static inline void switch_mm_0230(struct mm_struct *mm)
 227 {
 228         unsigned long crp[2] = {
 229                 0x80000000 | _PAGE_TABLE, mm->context
 230         };
 231         unsigned long tmp;
 232
 233         asm volatile (".chip 68030");
 234
 235         /* flush MC68030/MC68020 caches (they are virtually addressed) */
 236         asm volatile (
 237                 "movec %%cacr,%0;"
 238                 "orw %1,%0; "
 239                 "movec %0,%%cacr"
 240                 : "=d" (tmp) : "di" (FLUSH_I_AND_D));
 241
 242         /* Switch the root pointer. For a 030-only kernel,
 243          * avoid flushing the whole ATC, we only need to
 244          * flush the user entries. The 68851 does this by
 245          * itself. Avoid a runtime check here.
 246          */
 247         asm volatile (
 248 #ifdef CPU_M68030_ONLY
 249                 "pmovefd %0,%%crp; "
 250                 "pflush #0,#4"
 251 #else
 252                 "pmove %0,%%crp"
 253 #endif
 254                 : : "m" (crp[0]));
 255
 256         asm volatile (".chip 68k");
 257 }
 258
 259 static inline void switch_mm_0460(struct mm_struct *mm)
 260 {
 261         asm volatile (".chip 68040");
 262
 263         /* flush address translation cache (user entries) */
 264         asm volatile ("pflushan");
 265
 266         /* switch the root pointer */
 267         asm volatile ("movec %0,%%urp" : : "r" (mm->context));
 268
 269         if (CPU_IS_060) {
 270                 unsigned long tmp;
 271
 272                 /* clear user entries in the branch cache */
 273                 asm volatile (
 274                         "movec %%cacr,%0; "
 275                         "orl %1,%0; "
 276                         "movec %0,%%cacr"
 277                         : "=d" (tmp): "di" (0x00200000));
 278         }
 279
 280         asm volatile (".chip 68k");
 281 }
 282
 283 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
 284 {
 285         if (prev != next) {
 286                 if (CPU_IS_020_OR_030)
 287                         switch_mm_0230(next);
 288                 else
 289                         switch_mm_0460(next);
 290         }
 291 }
 292
 293 #define deactivate_mm(tsk,mm)   do { } while (0)
 294
 295 static inline void activate_mm(struct mm_struct *prev_mm,
 296                                struct mm_struct *next_mm)
 297 {
 298         next_mm->context = virt_to_phys(next_mm->pgd);
 299
 300         if (CPU_IS_020_OR_030)
 301                 switch_mm_0230(next_mm);
 302         else
 303                 switch_mm_0460(next_mm);
 304 }
 305
 306 #endif
 307
 308 #else /* !CONFIG_MMU */
 309
 310 static inline int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 311 {
 312         return 0;
 313 }
 314
 315
 316 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
 317 {
 318 }
 319
 320 #define destroy_context(mm)     do { } while (0)
 321 #define deactivate_mm(tsk,mm)   do { } while (0)
 322
 323 static inline void activate_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm)
 324 {
 325 }
 326
 327 #endif /* CONFIG_MMU */
 328 #endif /* __M68K_MMU_CONTEXT_H */