matos/drivers/zero.c

#include "zero.h"

#include "alloc.h"
#include "kernel.h"
#include "klibc.h"

struct zeroMappedEntry {
    int refCnt;
};

static int zeroOpen(struct uAddrVirtualReg *vreg)
{
    struct zeroMappedEntry *ent = (struct zeroMappedEntry *)vreg->res->customData;
    ent->refCnt++;
    return 0;
}

static int zeroClose(struct uAddrVirtualReg *vreg)
{
    struct zeroMappedEntry *ent = (struct zeroMappedEntry *)vreg->res->customData;
    ent->refCnt--;
    if (ent->refCnt == 0) {
        free(vreg->res->customData);
        free(vreg->res);
    }
    return 0;
}

static int zeroNoPage(struct uAddrVirtualReg *vreg, uaddr_t addr, int right)
{
    (void)vreg;

    int ret       = 0;
    paddr_t ppage = allocPhyPage(1);
    ret           = pageMap(ALIGN_DOWN(addr, PAGE_SIZE), ppage, right | PAGING_MEM_USER) ;

    unrefPhyPage(ppage);
    if (ret) {
        return ret;
    }
    memset((void *)ALIGN_DOWN(addr, PAGE_SIZE), 0, PAGE_SIZE);
    return ret;
}

static struct mappedRessourceOps zeroOps = {
    .open   = zeroOpen,
    .close  = zeroClose,
    .unmap  = NULL,
    .nopage = zeroNoPage,
};

int zeroOnMapped(struct uAddrVirtualReg *vreg)
{
    (void)vreg;
    return 0;
}

int zeroMmap(struct uAddrSpace *as, uaddr_t *uaddr, size_t size, uint32_t rights,
             uint32_t flags)
{
    int ret = 0;
    struct mappedRessource *res =
        (struct mappedRessource *)zalloc(sizeof(struct mappedRessource));
    struct zeroMappedEntry *cust =
        (struct zeroMappedEntry *)zalloc(sizeof(struct zeroMappedEntry));

    res->allowedRight = PAGING_MEM_READ | PAGING_MEM_WRITE | PAGING_MEM_EXEC | PAGING_MEM_USER;
    res->ops          = &zeroOps;
    res->customData   = cust;
    res->onResMapped = zeroOnMapped;

    ret = uAddrSpaceMmap(as, uaddr, size, rights, flags, res, 0);

    if (ret) {
        free(res);
        free(cust);
    }

    return ret;
}