LXR linux/arch/m68k/include/asm/mmu

   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
  21extern unsigned long context_map[];
  22extern mm_context_t next_mmu_context;
  23
  24extern atomic_t nr_free_contexts;
  25extern struct mm_struct *context_mm[LAST_CONTEXT+1];
  26extern void steal_context(void);
  27
  28static 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 (arch_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
  58static 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
  67static inline void set_context(mm_context_t context, pgd_t *pgd)
  68{
  69        __asm__ __volatile__ ("movec %0,%%asid" : : "d" (context));
  70}
  71
  72static 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
  84static 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
  93static 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
 161bug:
 162        pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
 163end:
 164        local_irq_restore(flags);
 165}
 166
 167#elif defined(CONFIG_SUN3)
 168#include <asm/sun3mmu.h>
 169#include <linux/sched.h>
 170
 171extern unsigned long get_free_context(struct mm_struct *mm);
 172extern 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
 176static 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. */
 185static 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
 193static inline void destroy_context(struct mm_struct *mm)
 194{
 195        if (mm->context != SUN3_INVALID_CONTEXT)
 196                clear_context(mm->context);
 197}
 198
 199static inline void activate_context(struct mm_struct *mm)
 200{
 201        get_mmu_context(mm);
 202        sun3_put_context(mm->context);
 203}
 204
 205static 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
 212static 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
 225static 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
 232static 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
 265static 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
 289static 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
 300static 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 */
 321