minix/servers/vm/mem_directphys.c
Ben Gras b538531449 vm: make WARNS=5 proof
Change-Id: I737ded223daf04f1c0c85a2e8e6b36c8fdcd07db
2013-09-06 11:51:20 +02:00

67 lines
1.8 KiB
C

/* This file implements the methods of direct physical mapping.
*
* A direct physical mapping is done by accepting the physical
* memory address and range from the caller and allowing direct
* access to it. Most significantly, no physical memory is allocated
* when it's mapped or freed when it's unmapped. E.g. device memory.
*/
#include "vm.h"
#include "proto.h"
/* These functions are static so as to not pollute the
* global namespace, and are accessed through their function
* pointers.
*/
static int phys_unreference(struct phys_region *pr);
static int phys_writable(struct phys_region *pr);
static int phys_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb, void *state,
int len, int *io);
static int phys_copy(struct vir_region *vr, struct vir_region *newvr);
struct mem_type mem_type_directphys = {
.name = "physical memory mapping",
.ev_copy = phys_copy,
.ev_unreference = phys_unreference,
.writable = phys_writable,
.ev_pagefault = phys_pagefault
};
static int phys_unreference(struct phys_region *pr)
{
return OK;
}
static int phys_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb, void *state,
int len, int *io)
{
phys_bytes arg = region->param.phys, phmem;
assert(arg != MAP_NONE);
assert(ph->ph->phys == MAP_NONE);
phmem = arg + ph->offset;
assert(phmem != MAP_NONE);
ph->ph->phys = phmem;
return OK;
}
static int phys_writable(struct phys_region *pr)
{
assert(pr->ph->refcount > 0);
return pr->ph->phys != MAP_NONE;
}
void phys_setphys(struct vir_region *vr, phys_bytes phys)
{
vr->param.phys = phys;
}
static int phys_copy(struct vir_region *vr, struct vir_region *newvr)
{
newvr->param.phys = vr->param.phys;
return OK;
}