/*      $OpenBSD: vm_machdep.c,v 1.43 2025/05/21 09:06:58 mpi Exp $     */
/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department and Ralph Campbell.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * from: Utah Hdr: vm_machdep.c 1.21 91/04/06
 *
 *      from: @(#)vm_machdep.c  8.3 (Berkeley) 1/4/94
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/user.h>
#include <sys/exec.h>
#include <sys/signalvar.h>

#include <uvm/uvm_extern.h>

#include <machine/cpu.h>
#include <mips64/mips_cpu.h>

extern void proc_trampoline(void);
/*
 * Finish a fork operation, with process p2 nearly set up.
 */
void
cpu_fork(struct proc *p1, struct proc *p2, void *stack, void *tcb,
    void (*func)(void *), void *arg)
{
        struct cpu_info *ci = curcpu();
        struct pcb *pcb;
#if UPAGES == 1
        paddr_t pa;

        /* replace p_addr with a direct translation address */
        p2->p_md.md_uarea = (vaddr_t)p2->p_addr;
        pmap_extract(pmap_kernel(), p2->p_md.md_uarea, &pa);
        p2->p_addr = (void *)PHYS_TO_XKPHYS(pa, CCA_CACHED);
#endif
        pcb = &p2->p_addr->u_pcb;

        /*
         * If we own the FPU, save its state before copying the PCB.
         */
        if (p1 == ci->ci_fpuproc)
                save_fpu();

        p2->p_md.md_flags = p1->p_md.md_flags & MDP_FORKSAVE;
#ifdef FPUEMUL
        if (!CPU_HAS_FPU(ci)) {
                p2->p_md.md_fppgva = p1->p_md.md_fppgva;
                KASSERT((p2->p_md.md_flags & MDP_FPUSED) == 0);
        }
#endif

        /* Copy pcb from p1 to p2 */
        if (p1 == curproc) {
                /* Sync the PCB before we copy it. */
                savectx(p1->p_addr, 0);
        }
#ifdef DIAGNOSTIC
        else if (p1 != &proc0)
                panic("cpu_fork: curproc");
#endif
        *pcb = p1->p_addr->u_pcb;
        p2->p_md.md_regs = &p2->p_addr->u_pcb.pcb_regs;

        /*
         * If specified, give the child a different stack and/or TCB.
         */
        if (stack != NULL)
                p2->p_md.md_regs->sp = (u_int64_t)stack;
        p2->p_md.md_tcb = tcb != NULL ? tcb : p1->p_md.md_tcb;

        /*
         * Copy the process control block to the new proc and
         * create a clean stack for exit through trampoline.
         * pcb_context has s0-s7, sp, s8, ra, sr.
         */
        if (p1 != curproc) {
                pcb->pcb_context.val[11] = (pcb->pcb_regs.sr & ~SR_INT_MASK) |
                    (idle_mask & SR_INT_MASK);
        }
        pcb->pcb_context.val[10] = (register_t)proc_trampoline;
        pcb->pcb_context.val[8] = (register_t)pcb +
            ((USPACE - sizeof(struct trapframe)) & ~_STACKALIGNBYTES);
        pcb->pcb_context.val[1] = (register_t)arg;
        pcb->pcb_context.val[0] = (register_t)func;
}

void
cpu_exit(struct proc *p)
{
        struct cpu_info *ci = curcpu();

        if (ci->ci_fpuproc == p)
                ci->ci_fpuproc = NULL;

#if UPAGES == 1
        /* restore p_addr for proper deallocation */
        p->p_addr = (void *)p->p_md.md_uarea;
#endif
}

struct kmem_va_mode kv_physwait = {
        .kv_map = &phys_map,
        .kv_wait = 1,
};

/*
 * Map an IO request into kernel virtual address space.
 */
void
vmapbuf(struct buf *bp, vsize_t len)
{
        struct kmem_dyn_mode kd_prefer = { .kd_waitok = 1 };
        struct pmap *pm = vm_map_pmap(&bp->b_proc->p_vmspace->vm_map);
        vaddr_t kva, uva;
        vsize_t size, off;

#ifdef DIAGNOSTIC
        if ((bp->b_flags & B_PHYS) == 0)
                panic("vmapbuf");
#endif
        bp->b_saveaddr = bp->b_data;
        uva = trunc_page((vaddr_t)bp->b_data);
        off = (vaddr_t)bp->b_data - uva;
        size = round_page(off + len);

        kd_prefer.kd_prefer = uva;
        kva = (vaddr_t)km_alloc(size, &kv_physwait, &kp_none, &kd_prefer);
        bp->b_data = (caddr_t)(kva + off);
        while (size > 0) {
                paddr_t pa;

                if (pmap_extract(pm, uva, &pa) == FALSE)
                        panic("vmapbuf: null page frame");
                else
                        pmap_kenter_pa(kva, pa, PROT_READ | PROT_WRITE);
                uva += PAGE_SIZE;
                kva += PAGE_SIZE;
                size -= PAGE_SIZE;
        }
        pmap_update(pmap_kernel());
}

/*
 * Unmap IO request from the kernel virtual address space.
 */
void
vunmapbuf(struct buf *bp, vsize_t len)
{
        vaddr_t addr, off;

#ifdef DIAGNOSTIC
        if ((bp->b_flags & B_PHYS) == 0)
                panic("vunmapbuf");
#endif
        addr = trunc_page((vaddr_t)bp->b_data);
        off = (vaddr_t)bp->b_data - addr;
        len = round_page(off + len);
        pmap_kremove(addr, len);
        pmap_update(pmap_kernel());
        km_free((void *)addr, len, &kv_physwait, &kp_none);
        bp->b_data = bp->b_saveaddr;
        bp->b_saveaddr = NULL;
}