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 #ifdef CONFIG_MMU
   9
  10 #if defined(CONFIG_COLDFIRE)
  11
  12 #include <asm/atomic.h>
  13 #include <asm/bitops.h>
  14 #include <asm/mcfmmu.h>
  15 #include <asm/mmu.h>
  16
  17 #define NO_CONTEXT              256
  18 #define LAST_CONTEXT            255
  19 #define FIRST_CONTEXT           1
  20
  21 extern unsigned long context_map[];
  22 extern mm_context_t next_mmu_context;
  23
  24 extern atomic_t nr_free_contexts;
  25 extern struct mm_struct *context_mm[LAST_CONTEXT+1];
  26 extern void steal_context(void);
  27
  28 static inline void get_mmu_context(struct mm_struct *mm)
  29 {
  30         mm_context_t ctx;
  31
  32         if (mm->context != NO_CONTEXT)
  33                 return;
  34         while (atomic_dec_and_test_lt(&nr_free_contexts)) {
  35                 atomic_inc(&nr_free_contexts);
  36                 steal_context();
  37         }
  38         ctx = next_mmu_context;
  39         while (test_and_set_bit(ctx, context_map)) {
  40                 ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
  41                 if (ctx > LAST_CONTEXT)
  42                         ctx = 0;
  43         }
  44         next_mmu_context = (ctx + 1) & LAST_CONTEXT;
  45         mm->context = ctx;
  46         context_mm[ctx] = mm;
  47 }
  48
  49 /*
  50  * Set up the context for a new address space.
  51  */
  52 #define init_new_context(tsk, mm)       (((mm)->context = NO_CONTEXT), 0)
  53
  54 /*
  55  * We're finished using the context for an address space.
  56  */
  57 #define destroy_context destroy_context
  58 static inline void destroy_context(struct mm_struct *mm)
  59 {
  60         if (mm->context != NO_CONTEXT) {
  61                 clear_bit(mm->context, context_map);
  62                 mm->context = NO_CONTEXT;
  63                 atomic_inc(&nr_free_contexts);
  64         }
  65 }
  66
  67 static inline void set_context(mm_context_t context, pgd_t *pgd)
  68 {
  69         __asm__ __volatile__ ("movec %0,%%asid" : : "d" (context));
  70 }
  71
  72 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  73         struct task_struct *tsk)
  74 {
  75         get_mmu_context(tsk->mm);
  76         set_context(tsk->mm->context, next->pgd);
  77 }
  78
  79 /*
  80  * After we have set current->mm to a new value, this activates
  81  * the context for the new mm so we see the new mappings.
  82  */
  83 #define activate_mm activate_mm
  84 static inline void activate_mm(struct mm_struct *active_mm,
  85         struct mm_struct *mm)
  86 {
  87         get_mmu_context(mm);
  88         set_context(mm->context, mm->pgd);
  89 }
  90
  91 #define prepare_arch_switch(next) load_ksp_mmu(next)
  92
  93 static inline void load_ksp_mmu(struct task_struct *task)
  94 {
  95         unsigned long flags;
  96         struct mm_struct *mm;
  97         int asid;
  98         pgd_t *pgd;
  99         p4d_t *p4d;
 100         pud_t *pud;
 101         pmd_t *pmd;
 102         pte_t *pte;
 103         unsigned long mmuar;
 104
 105         local_irq_save(flags);
 106         mmuar = task->thread.ksp;
 107
 108         /* Search for a valid TLB entry, if one is found, don't remap */
 109         mmu_write(MMUAR, mmuar);
 110         mmu_write(MMUOR, MMUOR_STLB | MMUOR_ADR);
 111         if (mmu_read(MMUSR) & MMUSR_HIT)
 112                 goto end;
 113
 114         if (mmuar >= PAGE_OFFSET) {
 115                 mm = &init_mm;
 116         } else {
 117                 pr_info("load_ksp_mmu: non-kernel mm found: 0x%p\n", task->mm);
 118                 mm = task->mm;
 119         }
 120
 121         if (!mm)
 122                 goto bug;
 123
 124         pgd = pgd_offset(mm, mmuar);
 125         if (pgd_none(*pgd))
 126                 goto bug;
 127
 128         p4d = p4d_offset(pgd, mmuar);
 129         if (p4d_none(*p4d))
 130                 goto bug;
 131
 132         pud = pud_offset(p4d, mmuar);
 133         if (pud_none(*pud))
 134                 goto bug;
 135
 136         pmd = pmd_offset(pud, mmuar);
 137         if (pmd_none(*pmd))
 138                 goto bug;
 139
 140         pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
 141                                      : pte_offset_map(pmd, mmuar);
 142         if (pte_none(*pte) || !pte_present(*pte))
 143                 goto bug;
 144
 145         set_pte(pte, pte_mkyoung(*pte));
 146         asid = mm->context & 0xff;
 147         if (!pte_dirty(*pte) && mmuar <= PAGE_OFFSET)
 148                 set_pte(pte, pte_wrprotect(*pte));
 149
 150         mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |
 151                 (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)
 152                 >> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);
 153
 154         mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
 155                 ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
 156
 157         mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
 158
 159         goto end;
 160
 161 bug:
 162         pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
 163 end:
 164         local_irq_restore(flags);
 165 }
 166
 167 #elif defined(CONFIG_SUN3)
 168 #include <asm/sun3mmu.h>
 169 #include <linux/sched.h>
 170
 171 extern unsigned long get_free_context(struct mm_struct *mm);
 172 extern void clear_context(unsigned long context);
 173
 174 /* set the context for a new task to unmapped */
 175 #define init_new_context init_new_context
 176 static inline int init_new_context(struct task_struct *tsk,
 177                                    struct mm_struct *mm)
 178 {
 179         mm->context = SUN3_INVALID_CONTEXT;
 180         return 0;
 181 }
 182
 183 /* find the context given to this process, and if it hasn't already
 184    got one, go get one for it. */
 185 static inline void get_mmu_context(struct mm_struct *mm)
 186 {
 187         if (mm->context == SUN3_INVALID_CONTEXT)
 188                 mm->context = get_free_context(mm);
 189 }
 190
 191 /* flush context if allocated... */
 192 #define destroy_context destroy_context
 193 static inline void destroy_context(struct mm_struct *mm)
 194 {
 195         if (mm->context != SUN3_INVALID_CONTEXT)
 196                 clear_context(mm->context);
 197 }
 198
 199 static inline void activate_context(struct mm_struct *mm)
 200 {
 201         get_mmu_context(mm);
 202         sun3_put_context(mm->context);
 203 }
 204
 205 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 206                              struct task_struct *tsk)
 207 {
 208         activate_context(tsk->mm);
 209 }
 210
 211 #define activate_mm activate_mm
 212 static inline void activate_mm(struct mm_struct *prev_mm,
 213                                struct mm_struct *next_mm)
 214 {
 215         activate_context(next_mm);
 216 }
 217
 218 #else
 219
 220 #include <asm/setup.h>
 221 #include <asm/page.h>
 222 #include <asm/cacheflush.h>
 223
 224 #define init_new_context init_new_context
 225 static inline int init_new_context(struct task_struct *tsk,
 226                                    struct mm_struct *mm)
 227 {
 228         mm->context = virt_to_phys(mm->pgd);
 229         return 0;
 230 }
 231
 232 static inline void switch_mm_0230(struct mm_struct *mm)
 233 {
 234         unsigned long crp[2] = {
 235                 0x80000000 | _PAGE_TABLE, mm->context
 236         };
 237         unsigned long tmp;
 238
 239         asm volatile (".chip 68030");
 240
 241         /* flush MC68030/MC68020 caches (they are virtually addressed) */
 242         asm volatile (
 243                 "movec %%cacr,%0;"
 244                 "orw %1,%0; "
 245                 "movec %0,%%cacr"
 246                 : "=d" (tmp) : "di" (FLUSH_I_AND_D));
 247
 248         /* Switch the root pointer. For a 030-only kernel,
 249          * avoid flushing the whole ATC, we only need to
 250          * flush the user entries. The 68851 does this by
 251          * itself. Avoid a runtime check here.
 252          */
 253         asm volatile (
 254 #ifdef CPU_M68030_ONLY
 255                 "pmovefd %0,%%crp; "
 256                 "pflush #0,#4"
 257 #else
 258                 "pmove %0,%%crp"
 259 #endif
 260                 : : "m" (crp[0]));
 261
 262         asm volatile (".chip 68k");
 263 }
 264
 265 static inline void switch_mm_0460(struct mm_struct *mm)
 266 {
 267         asm volatile (".chip 68040");
 268
 269         /* flush address translation cache (user entries) */
 270         asm volatile ("pflushan");
 271
 272         /* switch the root pointer */
 273         asm volatile ("movec %0,%%urp" : : "r" (mm->context));
 274
 275         if (CPU_IS_060) {
 276                 unsigned long tmp;
 277
 278                 /* clear user entries in the branch cache */
 279                 asm volatile (
 280                         "movec %%cacr,%0; "
 281                         "orl %1,%0; "
 282                         "movec %0,%%cacr"
 283                         : "=d" (tmp): "di" (0x00200000));
 284         }
 285
 286         asm volatile (".chip 68k");
 287 }
 288
 289 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
 290 {
 291         if (prev != next) {
 292                 if (CPU_IS_020_OR_030)
 293                         switch_mm_0230(next);
 294                 else
 295                         switch_mm_0460(next);
 296         }
 297 }
 298
 299 #define activate_mm activate_mm
 300 static inline void activate_mm(struct mm_struct *prev_mm,
 301                                struct mm_struct *next_mm)
 302 {
 303         next_mm->context = virt_to_phys(next_mm->pgd);
 304
 305         if (CPU_IS_020_OR_030)
 306                 switch_mm_0230(next_mm);
 307         else
 308                 switch_mm_0460(next_mm);
 309 }
 310
 311 #endif
 312
 313 #include <asm-generic/mmu_context.h>
 314
 315 #else /* !CONFIG_MMU */
 316
 317 #include <asm-generic/nommu_context.h>
 318
 319 #endif /* CONFIG_MMU */
 320 #endif /* __M68K_MMU_CONTEXT_H */