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         p4d_t *p4d;
 104         pud_t *pud;
 105         pmd_t *pmd;
 106         pte_t *pte;
 107         unsigned long mmuar;
 108
 109         local_irq_save(flags);
 110         mmuar = task->thread.ksp;
 111
 112         /* Search for a valid TLB entry, if one is found, don't remap */
 113         mmu_write(MMUAR, mmuar);
 114         mmu_write(MMUOR, MMUOR_STLB | MMUOR_ADR);
 115         if (mmu_read(MMUSR) & MMUSR_HIT)
 116                 goto end;
 117
 118         if (mmuar >= PAGE_OFFSET) {
 119                 mm = &init_mm;
 120         } else {
 121                 pr_info("load_ksp_mmu: non-kernel mm found: 0x%p\n", task->mm);
 122                 mm = task->mm;
 123         }
 124
 125         if (!mm)
 126                 goto bug;
 127
 128         pgd = pgd_offset(mm, mmuar);
 129         if (pgd_none(*pgd))
 130                 goto bug;
 131
 132         p4d = p4d_offset(pgd, mmuar);
 133         if (p4d_none(*p4d))
 134                 goto bug;
 135
 136         pud = pud_offset(p4d, mmuar);
 137         if (pud_none(*pud))
 138                 goto bug;
 139
 140         pmd = pmd_offset(pud, mmuar);
 141         if (pmd_none(*pmd))
 142                 goto bug;
 143
 144         pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
 145                                      : pte_offset_map(pmd, mmuar);
 146         if (pte_none(*pte) || !pte_present(*pte))
 147                 goto bug;
 148
 149         set_pte(pte, pte_mkyoung(*pte));
 150         asid = mm->context & 0xff;
 151         if (!pte_dirty(*pte) && mmuar <= PAGE_OFFSET)
 152                 set_pte(pte, pte_wrprotect(*pte));
 153
 154         mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |
 155                 (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)
 156                 >> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);
 157
 158         mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
 159                 ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
 160
 161         mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
 162
 163         goto end;
 164
 165 bug:
 166         pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
 167 end:
 168         local_irq_restore(flags);
 169 }
 170
 171 #elif defined(CONFIG_SUN3)
 172 #include <asm/sun3mmu.h>
 173 #include <linux/sched.h>
 174
 175 extern unsigned long get_free_context(struct mm_struct *mm);
 176 extern void clear_context(unsigned long context);
 177
 178 /* set the context for a new task to unmapped */
 179 static inline int init_new_context(struct task_struct *tsk,
 180                                    struct mm_struct *mm)
 181 {
 182         mm->context = SUN3_INVALID_CONTEXT;
 183         return 0;
 184 }
 185
 186 /* find the context given to this process, and if it hasn't already
 187    got one, go get one for it. */
 188 static inline void get_mmu_context(struct mm_struct *mm)
 189 {
 190         if (mm->context == SUN3_INVALID_CONTEXT)
 191                 mm->context = get_free_context(mm);
 192 }
 193
 194 /* flush context if allocated... */
 195 static inline void destroy_context(struct mm_struct *mm)
 196 {
 197         if (mm->context != SUN3_INVALID_CONTEXT)
 198                 clear_context(mm->context);
 199 }
 200
 201 static inline void activate_context(struct mm_struct *mm)
 202 {
 203         get_mmu_context(mm);
 204         sun3_put_context(mm->context);
 205 }
 206
 207 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 208                              struct task_struct *tsk)
 209 {
 210         activate_context(tsk->mm);
 211 }
 212
 213 #define deactivate_mm(tsk, mm)  do { } while (0)
 214
 215 static inline void activate_mm(struct mm_struct *prev_mm,
 216                                struct mm_struct *next_mm)
 217 {
 218         activate_context(next_mm);
 219 }
 220
 221 #else
 222
 223 #include <asm/setup.h>
 224 #include <asm/page.h>
 225 #include <asm/pgalloc.h>
 226
 227 static inline int init_new_context(struct task_struct *tsk,
 228                                    struct mm_struct *mm)
 229 {
 230         mm->context = virt_to_phys(mm->pgd);
 231         return 0;
 232 }
 233
 234 #define destroy_context(mm)             do { } while(0)
 235
 236 static inline void switch_mm_0230(struct mm_struct *mm)
 237 {
 238         unsigned long crp[2] = {
 239                 0x80000000 | _PAGE_TABLE, mm->context
 240         };
 241         unsigned long tmp;
 242
 243         asm volatile (".chip 68030");
 244
 245         /* flush MC68030/MC68020 caches (they are virtually addressed) */
 246         asm volatile (
 247                 "movec %%cacr,%0;"
 248                 "orw %1,%0; "
 249                 "movec %0,%%cacr"
 250                 : "=d" (tmp) : "di" (FLUSH_I_AND_D));
 251
 252         /* Switch the root pointer. For a 030-only kernel,
 253          * avoid flushing the whole ATC, we only need to
 254          * flush the user entries. The 68851 does this by
 255          * itself. Avoid a runtime check here.
 256          */
 257         asm volatile (
 258 #ifdef CPU_M68030_ONLY
 259                 "pmovefd %0,%%crp; "
 260                 "pflush #0,#4"
 261 #else
 262                 "pmove %0,%%crp"
 263 #endif
 264                 : : "m" (crp[0]));
 265
 266         asm volatile (".chip 68k");
 267 }
 268
 269 static inline void switch_mm_0460(struct mm_struct *mm)
 270 {
 271         asm volatile (".chip 68040");
 272
 273         /* flush address translation cache (user entries) */
 274         asm volatile ("pflushan");
 275
 276         /* switch the root pointer */
 277         asm volatile ("movec %0,%%urp" : : "r" (mm->context));
 278
 279         if (CPU_IS_060) {
 280                 unsigned long tmp;
 281
 282                 /* clear user entries in the branch cache */
 283                 asm volatile (
 284                         "movec %%cacr,%0; "
 285                         "orl %1,%0; "
 286                         "movec %0,%%cacr"
 287                         : "=d" (tmp): "di" (0x00200000));
 288         }
 289
 290         asm volatile (".chip 68k");
 291 }
 292
 293 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
 294 {
 295         if (prev != next) {
 296                 if (CPU_IS_020_OR_030)
 297                         switch_mm_0230(next);
 298                 else
 299                         switch_mm_0460(next);
 300         }
 301 }
 302
 303 #define deactivate_mm(tsk,mm)   do { } while (0)
 304
 305 static inline void activate_mm(struct mm_struct *prev_mm,
 306                                struct mm_struct *next_mm)
 307 {
 308         next_mm->context = virt_to_phys(next_mm->pgd);
 309
 310         if (CPU_IS_020_OR_030)
 311                 switch_mm_0230(next_mm);
 312         else
 313                 switch_mm_0460(next_mm);
 314 }
 315
 316 #endif
 317
 318 #else /* !CONFIG_MMU */
 319
 320 static inline int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 321 {
 322         return 0;
 323 }
 324
 325
 326 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
 327 {
 328 }
 329
 330 #define destroy_context(mm)     do { } while (0)
 331 #define deactivate_mm(tsk,mm)   do { } while (0)
 332
 333 static inline void activate_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm)
 334 {
 335 }
 336
 337 #endif /* CONFIG_MMU */
 338 #endif /* __M68K_MMU_CONTEXT_H */