/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __M68K_MMU_CONTEXT_H
#define __M68K_MMU_CONTEXT_H

#include <asm-generic/mm_hooks.h>
#include <linux/mm_types.h>

#ifdef CONFIG_MMU

#if defined(CONFIG_COLDFIRE)

#include <asm/atomic.h>
#include <asm/bitops.h>
#include <asm/mcfmmu.h>
#include <asm/mmu.h>

#define NO_CONTEXT              256
#define LAST_CONTEXT            255
#define FIRST_CONTEXT           1

extern unsigned long context_map[];
extern mm_context_t next_mmu_context;

extern atomic_t nr_free_contexts;
extern struct mm_struct *context_mm[LAST_CONTEXT+1];
extern void steal_context(void);

static inline void get_mmu_context(struct mm_struct *mm)
{
        mm_context_t ctx;

        if (mm->context != NO_CONTEXT)
                return;
        while (arch_atomic_dec_and_test_lt(&nr_free_contexts)) {
                atomic_inc(&nr_free_contexts);
                steal_context();
        }
        ctx = next_mmu_context;
        while (test_and_set_bit(ctx, context_map)) {
                ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
                if (ctx > LAST_CONTEXT)
                        ctx = 0;
        }
        next_mmu_context = (ctx + 1) & LAST_CONTEXT;
        mm->context = ctx;
        context_mm[ctx] = mm;
}

/*
 * Set up the context for a new address space.
 */
#define init_new_context(tsk, mm)       (((mm)->context = NO_CONTEXT), 0)

/*
 * We're finished using the context for an address space.
 */
#define destroy_context destroy_context
static inline void destroy_context(struct mm_struct *mm)
{
        if (mm->context != NO_CONTEXT) {
                clear_bit(mm->context, context_map);
                mm->context = NO_CONTEXT;
                atomic_inc(&nr_free_contexts);
        }
}

static inline void set_context(mm_context_t context, pgd_t *pgd)
{
        __asm__ __volatile__ ("movec %0,%%asid" : : "d" (context));
}

static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
        struct task_struct *tsk)
{
        get_mmu_context(tsk->mm);
        set_context(tsk->mm->context, next->pgd);
}

/*
 * After we have set current->mm to a new value, this activates
 * the context for the new mm so we see the new mappings.
 */
#define activate_mm activate_mm
static inline void activate_mm(struct mm_struct *active_mm,
        struct mm_struct *mm)
{
        get_mmu_context(mm);
        set_context(mm->context, mm->pgd);
}

#define prepare_arch_switch(next) load_ksp_mmu(next)

static inline void load_ksp_mmu(struct task_struct *task)
{
        unsigned long flags;
        struct mm_struct *mm;
        int asid;
        pgd_t *pgd;
        p4d_t *p4d;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte = NULL;
        unsigned long mmuar;

        local_irq_save(flags);
        mmuar = task->thread.ksp;

        /* Search for a valid TLB entry, if one is found, don't remap */
        mmu_write(MMUAR, mmuar);
        mmu_write(MMUOR, MMUOR_STLB | MMUOR_ADR);
        if (mmu_read(MMUSR) & MMUSR_HIT)
                goto end;

        if (mmuar >= PAGE_OFFSET) {
                mm = &init_mm;
        } else {
                pr_info("load_ksp_mmu: non-kernel mm found: 0x%p\n", task->mm);
                mm = task->mm;
        }

        if (!mm)
                goto bug;

        pgd = pgd_offset(mm, mmuar);
        if (pgd_none(*pgd))
                goto bug;

        p4d = p4d_offset(pgd, mmuar);
        if (p4d_none(*p4d))
                goto bug;

        pud = pud_offset(p4d, mmuar);
        if (pud_none(*pud))
                goto bug;

        pmd = pmd_offset(pud, mmuar);
        if (pmd_none(*pmd))
                goto bug;

        pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
                                     : pte_offset_map(pmd, mmuar);
        if (!pte || pte_none(*pte) || !pte_present(*pte))
                goto bug;

        set_pte(pte, pte_mkyoung(*pte));
        asid = mm->context & 0xff;
        if (!pte_dirty(*pte) && mmuar <= PAGE_OFFSET)
                set_pte(pte, pte_wrprotect(*pte));

        mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |
                (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)
                >> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);

        mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
                ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);

        mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);

        goto end;

bug:
        pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
end:
        if (pte && mmuar < PAGE_OFFSET)
                pte_unmap(pte);
        local_irq_restore(flags);
}

#elif defined(CONFIG_SUN3)
#include <asm/sun3mmu.h>
#include <linux/sched.h>

extern unsigned long get_free_context(struct mm_struct *mm);
extern void clear_context(unsigned long context);

/* set the context for a new task to unmapped */
#define init_new_context init_new_context
static inline int init_new_context(struct task_struct *tsk,
                                   struct mm_struct *mm)
{
        mm->context = SUN3_INVALID_CONTEXT;
        return 0;
}

/* find the context given to this process, and if it hasn't already
   got one, go get one for it. */
static inline void get_mmu_context(struct mm_struct *mm)
{
        if (mm->context == SUN3_INVALID_CONTEXT)
                mm->context = get_free_context(mm);
}

/* flush context if allocated... */
#define destroy_context destroy_context
static inline void destroy_context(struct mm_struct *mm)
{
        if (mm->context != SUN3_INVALID_CONTEXT)
                clear_context(mm->context);
}

static inline void activate_context(struct mm_struct *mm)
{
        get_mmu_context(mm);
        sun3_put_context(mm->context);
}

static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
                             struct task_struct *tsk)
{
        activate_context(tsk->mm);
}

#define activate_mm activate_mm
static inline void activate_mm(struct mm_struct *prev_mm,
                               struct mm_struct *next_mm)
{
        activate_context(next_mm);
}

#else

#include <asm/setup.h>
#include <asm/page.h>
#include <asm/cacheflush.h>

#define init_new_context init_new_context
static inline int init_new_context(struct task_struct *tsk,
                                   struct mm_struct *mm)
{
        mm->context = virt_to_phys(mm->pgd);
        return 0;
}

static inline void switch_mm_0230(struct mm_struct *mm)
{
        unsigned long crp[2] = {
                0x80000000 | _PAGE_TABLE, mm->context
        };
        unsigned long tmp;

        asm volatile (".chip 68030");

        /* flush MC68030/MC68020 caches (they are virtually addressed) */
        asm volatile (
                "movec %%cacr,%0;"
                "orw %1,%0; "
                "movec %0,%%cacr"
                : "=d" (tmp) : "di" (FLUSH_I_AND_D));

        /* Switch the root pointer. For a 030-only kernel,
         * avoid flushing the whole ATC, we only need to
         * flush the user entries. The 68851 does this by
         * itself. Avoid a runtime check here.
         */
        asm volatile (
#ifdef CPU_M68030_ONLY
                "pmovefd %0,%%crp; "
                "pflush #0,#4"
#else
                "pmove %0,%%crp"
#endif
                : : "m" (crp[0]));

        asm volatile (".chip 68k");
}

static inline void switch_mm_0460(struct mm_struct *mm)
{
        asm volatile (".chip 68040");

        /* flush address translation cache (user entries) */
        asm volatile ("pflushan");

        /* switch the root pointer */
        asm volatile ("movec %0,%%urp" : : "r" (mm->context));

        if (CPU_IS_060) {
                unsigned long tmp;

                /* clear user entries in the branch cache */
                asm volatile (
                        "movec %%cacr,%0; "
                        "orl %1,%0; "
                        "movec %0,%%cacr"
                        : "=d" (tmp): "di" (0x00200000));
        }

        asm volatile (".chip 68k");
}

static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
{
        if (prev != next) {
                if (CPU_IS_020_OR_030)
                        switch_mm_0230(next);
                else
                        switch_mm_0460(next);
        }
}

#define activate_mm activate_mm
static inline void activate_mm(struct mm_struct *prev_mm,
                               struct mm_struct *next_mm)
{
        next_mm->context = virt_to_phys(next_mm->pgd);

        if (CPU_IS_020_OR_030)
                switch_mm_0230(next_mm);
        else
                switch_mm_0460(next_mm);
}

#endif

#include <asm-generic/mmu_context.h>

#else /* !CONFIG_MMU */

#include <asm-generic/nommu_context.h>

#endif /* CONFIG_MMU */
#endif /* __M68K_MMU_CONTEXT_H */