/*      $NetBSD: vm_machdep.c,v 1.79 2024/01/15 20:35:22 andvar Exp $   */

/*
 * Copyright (c) 1994-1998 Mark Brinicombe.
 * Copyright (c) 1994 Brini.
 * All rights reserved.
 *
 * This code is derived from software written for Brini by Mark Brinicombe
 *
 * 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 Brini.
 * 4. The name of the company nor the name of the author may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY BRINI ``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 BRINI 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.
 *
 * RiscBSD kernel project
 *
 * vm_machdep.h
 *
 * vm machine specific bits
 *
 * Created      : 08/10/94
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.79 2024/01/15 20:35:22 andvar Exp $");

#include "opt_armfpe.h"
#include "opt_cputypes.h"

#include <sys/param.h>

#include <sys/buf.h>
#include <sys/cpu.h>
#include <sys/exec.h>
#include <sys/proc.h>
#ifdef STACKCHECKS
#include <sys/syslog.h>
#endif
#include <sys/systm.h>
#include <sys/vnode.h>

#include <uvm/uvm_extern.h>

#include <arm/vfpreg.h>

#include <machine/pcb.h>
#include <machine/pmap.h>
#include <machine/reg.h>
#include <machine/vmparam.h>

void lwp_trampoline(void);

/*
 * Special compilation symbols:
 *
 * STACKCHECKS - Fill undefined and supervisor stacks with a known pattern
 *               on forking and check the pattern on exit, reporting
 *               the amount of stack used.
 */

void
cpu_proc_fork(struct proc *p1, struct proc *p2)
{
        /*
         * Copy machine arch string (it's small so just memcpy it).
         */
        memcpy(p2->p_md.md_march, p1->p_md.md_march, sizeof(p2->p_md.md_march));
}

/*
 * Finish a fork operation, with LWP l2 nearly set up.
 *
 * Copy and update the pcb and trapframe, making the child ready to run.
 *
 * Rig the child's kernel stack so that it will start out in
 * lwp_trampoline() which will call the specified func with the argument arg.
 *
 * If an alternate user-level stack is requested (with non-zero values
 * in both the stack and stacksize args), set up the user stack pointer
 * accordingly.
 */
void
cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize,
    void (*func)(void *), void *arg)
{
        struct switchframe *sf;
        vaddr_t uv;

        const struct pcb * const pcb1 = lwp_getpcb(l1);
        struct pcb * const pcb2 = lwp_getpcb(l2);

#ifdef XXXDEBUG
        printf("cpu_lwp_fork: %p %p %p %p\n", l1, l2, curlwp, &lwp0);
#endif  /* DEBUG */

        /* Copy the pcb */
        *pcb2 = *pcb1;

#ifdef FPU_VFP
        /*
         * Disable the VFP for a newly created LWP but remember if the
         * VFP state is valid.
         */
        pcb2->pcb_vfp.vfp_fpexc &= ~VFP_FPEXC_EN;
#endif

        /*
         * Set up the kernel stack for the process.
         * Note: this stack is not in use if we are forking from p1
         */
        uv = uvm_lwp_getuarea(l2);
        pcb2->pcb_ksp = uv + USPACE_SVC_STACK_TOP;

#ifdef STACKCHECKS
        /* Fill the kernel stack with a known pattern */
        memset((void *)(uv + USPACE_SVC_STACK_BOTTOM), 0xdd,
            (USPACE_SVC_STACK_TOP - USPACE_SVC_STACK_BOTTOM));
#endif  /* STACKCHECKS */

#ifdef XXXDEBUG
        printf("l1: pcb=%p pid=%d pmap=%p\n",
            pcb1, l1->l_lid, l1->l_proc->p_vmspace->vm_map.pmap);
        printf("l2: pcb=%p pid=%d pmap=%p\n",
            pcb2, l2->l_lid, l2->l_proc->p_vmspace->vm_map.pmap);
#endif  /* DEBUG */

        struct trapframe *tf = (struct trapframe *)pcb2->pcb_ksp - 1;
        lwp_settrapframe(l2, tf);
        *tf = *lwp_trapframe(l1);

        /*
         * If specified, give the child a different stack (make sure
         * it's 8-byte aligned).
         */
        if (stack != NULL)
                tf->tf_usr_sp = ((vaddr_t)(stack) + stacksize) & -8;

        sf = (struct switchframe *)tf - 1;
        sf->sf_r4 = (u_int)func;
        sf->sf_r5 = (u_int)arg;
        sf->sf_r7 = PSR_USR32_MODE;             /* for returning to userspace */
        sf->sf_sp = (u_int)tf;
        sf->sf_pc = (u_int)lwp_trampoline;
        pcb2->pcb_ksp = (u_int)sf;
}

/*
 * cpu_exit is called as the last action during exit.
 *
 * We clean up a little and then call switch_exit() with the old proc as an
 * argument.  switch_exit() first switches to lwp0's context, and finally
 * jumps into switch() to wait for another process to wake up.
 */

void
cpu_lwp_free(struct lwp *l, int proc)
{
#ifdef STACKCHECKS
        /* Report how much stack has been used - debugging */
        struct pcb * const pcb = lwp_getpcb(l);
        u_char *ptr;
        u_int loop;

        ptr = (u_char *)pcb + USPACE_SVC_STACK_BOTTOM;
        for (loop = 0; loop < (USPACE_SVC_STACK_TOP - USPACE_SVC_STACK_BOTTOM)
            && *ptr == 0xdd; ++loop, ++ptr) ;
        log(LOG_INFO, "%u bytes of svc stack fill pattern\n", loop);
#endif  /* STACKCHECKS */
}

void
cpu_lwp_free2(struct lwp *l)
{
}

/*
 * Map a user I/O request into kernel virtual address space.
 * Note: the pages are already locked by uvm_vslock(), so we
 * do not need to pass an access_type to pmap_enter().
 */
int
vmapbuf(struct buf *bp, vsize_t len)
{
        struct pmap * const pm = vm_map_pmap(&bp->b_proc->p_vmspace->vm_map);
        vaddr_t faddr, taddr, off;
        paddr_t fpa;

        KASSERT(pm != pmap_kernel());

#ifdef XXXDEBUG
        printf("vmapbuf: bp=%08x buf=%08x len=%08x\n", (u_int)bp,
            (u_int)bp->b_data, (u_int)len);
#endif  /* XXXDEBUG */

        if ((bp->b_flags & B_PHYS) == 0)
                panic("vmapbuf");

        bp->b_saveaddr = bp->b_data;
        faddr = trunc_page((vaddr_t)bp->b_data);
        off = (vaddr_t)bp->b_data - faddr;
        len = round_page(off + len);
        taddr = uvm_km_alloc(phys_map, len, atop(faddr) & uvmexp.colormask,
            UVM_KMF_VAONLY | UVM_KMF_WAITVA | UVM_KMF_COLORMATCH);
        bp->b_data = (void *)(taddr + off);

        /*
         * The region is locked, so we expect that pmap_extract() will return
         * true.
         */
        while (len) {
                (void) pmap_extract(pm, faddr, &fpa);
                pmap_enter(pmap_kernel(), taddr, fpa, VM_PROT_READ|VM_PROT_WRITE,
                    VM_PROT_READ|VM_PROT_WRITE|PMAP_WIRED);
                faddr += PAGE_SIZE;
                taddr += PAGE_SIZE;
                len -= PAGE_SIZE;
        }
        pmap_update(pmap_kernel());

        return 0;
}

/*
 * Unmap a previously-mapped user I/O request.
 */
void
vunmapbuf(struct buf *bp, vsize_t len)
{
        vaddr_t addr, off;

#ifdef XXXDEBUG
        printf("vunmapbuf: bp=%08x buf=%08x len=%08x\n",
            (u_int)bp, (u_int)bp->b_data, (u_int)len);
#endif  /* XXXDEBUG */

        if ((bp->b_flags & B_PHYS) == 0)
                panic("vunmapbuf");

        /*
         * Make sure the cache does not have dirty data for the
         * pages we had mapped.
         */
        addr = trunc_page((vaddr_t)bp->b_data);
        off = (vaddr_t)bp->b_data - addr;
        len = round_page(off + len);

        pmap_remove(pmap_kernel(), addr, addr + len);
        pmap_update(pmap_kernel());
        uvm_km_free(phys_map, addr, len, UVM_KMF_VAONLY);
        bp->b_data = bp->b_saveaddr;
        bp->b_saveaddr = 0;
}

void
ktext_write(void *to, const void *from, size_t size)
{
        struct pmap *pmap = pmap_kernel();
        pd_entry_t *pde, oldpde, tmppde;
        pt_entry_t *pte, oldpte, tmppte;
        vaddr_t pgva;
        size_t limit, savesize;
        const char *src;
        char *dst;

        /* XXX: gcc */
        oldpte = 0;

        if ((savesize = size) == 0)
                return;

        dst = (char *) to;
        src = (const char *) from;

        do {
                /* Get the PDE of the current VA. */
                if (pmap_get_pde_pte(pmap, (vaddr_t) dst, &pde, &pte) == false)
                        goto no_mapping;
                switch ((oldpde = *pde) & L1_TYPE_MASK) {
                case L1_TYPE_S:
                        pgva = (vaddr_t)dst & L1_S_FRAME;
                        limit = L1_S_SIZE - ((vaddr_t)dst & L1_S_OFFSET);

                        tmppde = l1pte_set_writable(oldpde);
                        *pde = tmppde;
                        PTE_SYNC(pde);
                        break;

                case L1_TYPE_C:
                        pgva = (vaddr_t)dst & L2_S_FRAME;
                        limit = L2_S_SIZE - ((vaddr_t)dst & L2_S_OFFSET);

                        if (pte == NULL)
                                goto no_mapping;
                        oldpte = *pte;
                        tmppte = l2pte_set_writable(oldpte);
                        *pte = tmppte;
                        PTE_SYNC(pte);
                        break;

                default:
                no_mapping:
                        printf(" address 0x%08lx not a valid page\n",
                            (vaddr_t) dst);
                        return;
                }
                cpu_tlb_flushD_SE(pgva);
                cpu_cpwait();

                if (limit > size)
                        limit = size;
                size -= limit;

                /*
                 * Page is now writable.  Do as much access as we
                 * can in this page.
                 */
                for (; limit > 0; limit--)
                        *dst++ = *src++;

                /*
                 * Restore old mapping permissions.
                 */
                switch (oldpde & L1_TYPE_MASK) {
                case L1_TYPE_S:
                        *pde = oldpde;
                        PTE_SYNC(pde);
                        break;

                case L1_TYPE_C:
                        *pte = oldpte;
                        PTE_SYNC(pte);
                        break;
                }
                cpu_tlb_flushD_SE(pgva);
                cpu_cpwait();
        } while (size != 0);

        /* Sync the I-cache. */
        cpu_icache_sync_range((vaddr_t)to, savesize);
}

/* End of vm_machdep.c */