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/*
* \brief Virtual page-table facility
* \author Thomas Friebel <tf13@os.inf.tu-dresden.de>
* \author Christian Helmuth <ch12@os.inf.tu-dresden.de>
* \date 2006-11-01
*
* This implementation uses l4rm (especially the AVL tree and userptr) to
* manage virt->phys mappings. Each mapping region is represented by one
* pgtab_object that is kept in the l4rm region userptr.
*
* For this to work, dataspaces must be attached to l4rm regions!
*/
#include <unistd.h>
#include <error.h>
#include <errno.h>
#include <mach.h>
#include <cthreads.h>
#include "ddekit/pgtab.h"
#include "util.h"
#include "config.h"
/* A structure of recording a region of memory. */
struct entry
{
void *virtual;
ddekit_addr_t physical;
int size;
int type;
};
static struct entry *regions;
/* The number of memory regions in the array REGIONS */
static int num_regions;
/* The size of the array REGIONS */
static int capability;
static struct mutex lock;
#define INIT_SIZE 128
/*****************************
** Page-table facility API **
*****************************/
static struct entry *get_entry_from_phys (const ddekit_addr_t phys)
{
int i;
for (i = 0; i < num_regions; i++)
{
if (regions[i].physical <= phys
&& regions[i].physical + regions[i].size > phys)
return ®ions[i];
}
return NULL;
}
static struct entry *get_entry_from_virt (const ddekit_addr_t virt)
{
int i;
for (i = 0; i < num_regions; i++)
{
if ((ddekit_addr_t) regions[i].virtual <= virt
&& ((ddekit_addr_t) regions[i].virtual)
+ regions[i].size > virt)
return ®ions[i];
}
return NULL;
}
/**
* Get physical address for virtual address
*
* \param virtual virtual address
* \return physical address or 0
*/
ddekit_addr_t ddekit_pgtab_get_physaddr(const void *virtual)
{
struct entry *e;
mutex_lock (&lock);
e = get_entry_from_virt ((ddekit_addr_t) virtual);
if (e)
{
ddekit_addr_t phys = e->physical + (virtual - e->virtual);
mutex_unlock (&lock);
return phys;
}
mutex_unlock (&lock);
ddekit_printf ("a virtual address %p doesn't exist.\n", virtual);
return -1;
}
/**
* Get virtual address for physical address
*
* \param physical physical address
* \return virtual address or 0
*/
ddekit_addr_t ddekit_pgtab_get_virtaddr(const ddekit_addr_t physical)
{
struct entry *e;
mutex_lock (&lock);
e = get_entry_from_phys (physical);
if (e)
{
ddekit_addr_t virt = (ddekit_addr_t) e->virtual
+ (physical - e->physical);
mutex_unlock (&lock);
return virt;
}
mutex_unlock (&lock);
ddekit_printf ("a physical address %p doesn't exist.\n", physical);
return -1;
}
// TODO
int ddekit_pgtab_get_type(const void *virtual)
{
#if 0
/* find pgtab object */
struct pgtab_object *p = l4rm_get_userptr(virtual);
if (!p) {
/* XXX this is verbose */
LOG_Error("no virt->phys mapping for %p", virtual);
return -1;
}
return p->type;
#endif
UNIMPL;
return 0;
}
int ddekit_pgtab_get_size(const void *virtual)
{
struct entry *e;
mutex_lock (&lock);
e = get_entry_from_virt ((ddekit_addr_t) virtual);
if (e)
{
int size = e->size;
mutex_unlock (&lock);
return size;
}
mutex_unlock (&lock);
return 0;
}
/**
* Clear virtual->physical mapping for VM region
*
* \param virtual virtual start address for region
* \param type pgtab type for region
*/
void ddekit_pgtab_clear_region(void *virtual, int type)
{
struct entry *e;
mutex_lock (&lock);
e = get_entry_from_virt ((ddekit_addr_t) virtual);
if (e)
{
*e = regions[num_regions - 1];
num_regions--;
}
mutex_unlock (&lock);
}
/**
* Set virtual->physical mapping for VM region
*
* \param virtual virtual start address for region
* \param physical physical start address for region
* \param pages number of pages in region
* \param type pgtab type for region
*/
void ddekit_pgtab_set_region(void *virtual, ddekit_addr_t physical, int pages, int type)
{
ddekit_pgtab_set_region (virtual, physical, pages * getpagesize (), type);
}
void ddekit_pgtab_set_region_with_size(void *virt, ddekit_addr_t phys, int size, int type)
{
mutex_lock (&lock);
if (num_regions == capability)
{
capability *= 2;
regions = realloc (regions, capability * sizeof (struct entry));
if (regions == NULL)
error (2, errno, "realloc");
}
regions[num_regions].virtual = virt;
regions[num_regions].physical = phys;
regions[num_regions].size = size;
regions[num_regions].type = type;
num_regions++;
mutex_unlock (&lock);
ddekit_printf ("******there are %d regions (%d bytes)\n",
num_regions, size);
}
int pgtab_init ()
{
capability = INIT_SIZE;
regions = malloc (sizeof (struct entry) * capability);
mutex_init (&lock);
return 0;
}
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