/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SPARC64_MMU_CONTEXT_H
#define __SPARC64_MMU_CONTEXT_H

/* Derived heavily from Linus's Alpha/AXP ASN code... */

#ifndef __ASSEMBLY__

#include <linux/spinlock.h>
#include <linux/mm_types.h>
#include <linux/smp.h>
#include <linux/sched.h>

#include <asm/spitfire.h>
#include <asm/adi_64.h>
#include <asm-generic/mm_hooks.h>
#include <asm/percpu.h>

extern spinlock_t ctx_alloc_lock;
extern unsigned long tlb_context_cache;
extern unsigned long mmu_context_bmap[];

DECLARE_PER_CPU(struct mm_struct *, per_cpu_secondary_mm);
void get_new_mmu_context(struct mm_struct *mm);

#define init_new_context init_new_context
int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
#define destroy_context destroy_context
void destroy_context(struct mm_struct *mm);

void __tsb_context_switch(unsigned long pgd_pa,
                          struct tsb_config *tsb_base,
                          struct tsb_config *tsb_huge,
                          unsigned long tsb_descr_pa,
                          unsigned long secondary_ctx);

static inline void tsb_context_switch_ctx(struct mm_struct *mm,
                                          unsigned long ctx)
{
        __tsb_context_switch(__pa(mm->pgd),
                             &mm->context.tsb_block[MM_TSB_BASE],
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
                             (mm->context.tsb_block[MM_TSB_HUGE].tsb ?
                              &mm->context.tsb_block[MM_TSB_HUGE] :
                              NULL)
#else
                             NULL
#endif
                             , __pa(&mm->context.tsb_descr[MM_TSB_BASE]),
                             ctx);
}

#define tsb_context_switch(X) tsb_context_switch_ctx(X, 0)

void tsb_grow(struct mm_struct *mm,
              unsigned long tsb_index,
              unsigned long mm_rss);
#ifdef CONFIG_SMP
void smp_tsb_sync(struct mm_struct *mm);
#else
#define smp_tsb_sync(__mm) do { } while (0)
#endif

/* Set MMU context in the actual hardware. */
#define load_secondary_context(__mm) \
        __asm__ __volatile__( \
        "\n661: stxa            %0, [%1] %2\n" \
        "       .section        .sun4v_1insn_patch, \"ax\"\n" \
        "       .word           661b\n" \
        "       stxa            %0, [%1] %3\n" \
        "       .previous\n" \
        "       flush           %%g6\n" \
        : /* No outputs */ \
        : "r" (CTX_HWBITS((__mm)->context)), \
          "r" (SECONDARY_CONTEXT), "i" (ASI_DMMU), "i" (ASI_MMU))

void __flush_tlb_mm(unsigned long, unsigned long);

/* Switch the current MM context. */
static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
{
        unsigned long ctx_valid, flags;
        int cpu = smp_processor_id();

        per_cpu(per_cpu_secondary_mm, cpu) = mm;
        if (unlikely(mm == &init_mm))
                return;

        spin_lock_irqsave(&mm->context.lock, flags);
        ctx_valid = CTX_VALID(mm->context);
        if (!ctx_valid)
                get_new_mmu_context(mm);

        /* We have to be extremely careful here or else we will miss
         * a TSB grow if we switch back and forth between a kernel
         * thread and an address space which has it's TSB size increased
         * on another processor.
         *
         * It is possible to play some games in order to optimize the
         * switch, but the safest thing to do is to unconditionally
         * perform the secondary context load and the TSB context switch.
         *
         * For reference the bad case is, for address space "A":
         *
         *              CPU 0                   CPU 1
         *      run address space A
         *      set cpu0's bits in cpu_vm_mask
         *      switch to kernel thread, borrow
         *      address space A via entry_lazy_tlb
         *                                      run address space A
         *                                      set cpu1's bit in cpu_vm_mask
         *                                      flush_tlb_pending()
         *                                      reset cpu_vm_mask to just cpu1
         *                                      TSB grow
         *      run address space A
         *      context was valid, so skip
         *      TSB context switch
         *
         * At that point cpu0 continues to use a stale TSB, the one from
         * before the TSB grow performed on cpu1.  cpu1 did not cross-call
         * cpu0 to update it's TSB because at that point the cpu_vm_mask
         * only had cpu1 set in it.
         */
        tsb_context_switch_ctx(mm, CTX_HWBITS(mm->context));

        /* Any time a processor runs a context on an address space
         * for the first time, we must flush that context out of the
         * local TLB.
         */
        if (!ctx_valid || !cpumask_test_cpu(cpu, mm_cpumask(mm))) {
                cpumask_set_cpu(cpu, mm_cpumask(mm));
                __flush_tlb_mm(CTX_HWBITS(mm->context),
                               SECONDARY_CONTEXT);
        }
        spin_unlock_irqrestore(&mm->context.lock, flags);
}

#define activate_mm(active_mm, mm) switch_mm(active_mm, mm, NULL)

#define  __HAVE_ARCH_START_CONTEXT_SWITCH
static inline void arch_start_context_switch(struct task_struct *prev)
{
        /* Save the current state of MCDPER register for the process
         * we are switching from
         */
        if (adi_capable()) {
                register unsigned long tmp_mcdper;

                __asm__ __volatile__(
                        ".word 0x83438000\n\t"  /* rd  %mcdper, %g1 */
                        "mov %%g1, %0\n\t"
                        : "=r" (tmp_mcdper)
                        :
                        : "g1");
                if (tmp_mcdper)
                        set_tsk_thread_flag(prev, TIF_MCDPER);
                else
                        clear_tsk_thread_flag(prev, TIF_MCDPER);
        }
}

#define finish_arch_post_lock_switch    finish_arch_post_lock_switch
static inline void finish_arch_post_lock_switch(void)
{
        /* Restore the state of MCDPER register for the new process
         * just switched to.
         */
        if (adi_capable()) {
                register unsigned long tmp_mcdper;

                tmp_mcdper = test_thread_flag(TIF_MCDPER);
                __asm__ __volatile__(
                        "mov %0, %%g1\n\t"
                        ".word 0x9d800001\n\t"  /* wr %g0, %g1, %mcdper" */
                        ".word 0xaf902001\n\t"  /* wrpr %g0, 1, %pmcdper */
                        :
                        : "ir" (tmp_mcdper)
                        : "g1");
                if (current && current->mm && current->mm->context.adi) {
                        struct pt_regs *regs;

                        regs = task_pt_regs(current);
                        regs->tstate |= TSTATE_MCDE;
                }
        }
}

#include <asm-generic/mmu_context.h>

#endif /* !(__ASSEMBLY__) */

#endif /* !(__SPARC64_MMU_CONTEXT_H) */