141 lines
3.5 KiB
C
141 lines
3.5 KiB
C
|
|
/* This file implements the methods of anonymous memory.
|
|
*
|
|
* Anonymous memory is memory that is for private use to a process
|
|
* and can not be related to a file (hence anonymous).
|
|
*/
|
|
|
|
#include <assert.h>
|
|
|
|
#include "proto.h"
|
|
#include "vm.h"
|
|
#include "region.h"
|
|
#include "glo.h"
|
|
|
|
/* These functions are static so as to not pollute the
|
|
* global namespace, and are accessed through their function
|
|
* pointers.
|
|
*/
|
|
|
|
static void anon_split(struct vmproc *vmp, struct vir_region *vr,
|
|
struct vir_region *r1, struct vir_region *r2);
|
|
static int anon_lowshrink(struct vir_region *vr, vir_bytes len);
|
|
static int anon_unreference(struct phys_region *pr);
|
|
static int anon_pagefault(struct vmproc *vmp, struct vir_region *region,
|
|
struct phys_region *ph, int write, vfs_callback_t cb, void *, int);
|
|
static int anon_sanitycheck(struct phys_region *pr, char *file, int line);
|
|
static int anon_writable(struct phys_region *pr);
|
|
static int anon_resize(struct vmproc *vmp, struct vir_region *vr, vir_bytes l);
|
|
static u32_t anon_regionid(struct vir_region *region);
|
|
static int anon_refcount(struct vir_region *vr);
|
|
|
|
struct mem_type mem_type_anon = {
|
|
.name = "anonymous memory",
|
|
.ev_unreference = anon_unreference,
|
|
.ev_pagefault = anon_pagefault,
|
|
.ev_resize = anon_resize,
|
|
.ev_sanitycheck = anon_sanitycheck,
|
|
.ev_lowshrink = anon_lowshrink,
|
|
.ev_split = anon_split,
|
|
.regionid = anon_regionid,
|
|
.writable = anon_writable,
|
|
.refcount = anon_refcount
|
|
};
|
|
|
|
static int anon_unreference(struct phys_region *pr)
|
|
{
|
|
assert(pr->ph->refcount == 0);
|
|
if(pr->ph->phys != MAP_NONE)
|
|
free_mem(ABS2CLICK(pr->ph->phys), 1);
|
|
return OK;
|
|
}
|
|
|
|
static int anon_pagefault(struct vmproc *vmp, struct vir_region *region,
|
|
struct phys_region *ph, int write, vfs_callback_t cb, void *st, int l)
|
|
{
|
|
phys_bytes new_page, new_page_cl;
|
|
u32_t allocflags;
|
|
|
|
allocflags = vrallocflags(region->flags);
|
|
|
|
assert(ph->ph->refcount > 0);
|
|
|
|
if((new_page_cl = alloc_mem(1, allocflags)) == NO_MEM) {
|
|
printf("anon_pagefault: out of memory\n");
|
|
return ENOMEM;
|
|
}
|
|
new_page = CLICK2ABS(new_page_cl);
|
|
|
|
/* Totally new block? Create it. */
|
|
if(ph->ph->phys == MAP_NONE) {
|
|
ph->ph->phys = new_page;
|
|
assert(ph->ph->phys != MAP_NONE);
|
|
|
|
return OK;
|
|
}
|
|
|
|
if(ph->ph->refcount < 2 || !write) {
|
|
printf("anon_pagefault: %d refcount, %d write - not handling pagefault\n",
|
|
ph->ph->refcount, write);
|
|
return OK;
|
|
}
|
|
|
|
assert(region->flags & VR_WRITABLE);
|
|
|
|
return mem_cow(region, ph, new_page_cl, new_page);
|
|
}
|
|
|
|
static int anon_sanitycheck(struct phys_region *pr, char *file, int line)
|
|
{
|
|
MYASSERT(usedpages_add(pr->ph->phys, VM_PAGE_SIZE) == OK);
|
|
return OK;
|
|
}
|
|
|
|
static int anon_writable(struct phys_region *pr)
|
|
{
|
|
assert(pr->ph->refcount > 0);
|
|
if(pr->ph->phys == MAP_NONE)
|
|
return 0;
|
|
if(pr->parent->remaps > 0)
|
|
return 1;
|
|
return pr->ph->refcount == 1;
|
|
}
|
|
|
|
static int anon_resize(struct vmproc *vmp, struct vir_region *vr, vir_bytes l)
|
|
{
|
|
/* Shrinking not implemented; silently ignored.
|
|
* (Which is ok for brk().)
|
|
*/
|
|
if(l <= vr->length)
|
|
return OK;
|
|
|
|
assert(vr);
|
|
assert(vr->flags & VR_ANON);
|
|
assert(!(l % VM_PAGE_SIZE));
|
|
|
|
USE(vr, vr->length = l;);
|
|
|
|
return OK;
|
|
}
|
|
|
|
static u32_t anon_regionid(struct vir_region *region)
|
|
{
|
|
return region->id;
|
|
}
|
|
|
|
static int anon_lowshrink(struct vir_region *vr, vir_bytes len)
|
|
{
|
|
return OK;
|
|
}
|
|
|
|
static int anon_refcount(struct vir_region *vr)
|
|
{
|
|
return 1 + vr->remaps;
|
|
}
|
|
|
|
static void anon_split(struct vmproc *vmp, struct vir_region *vr,
|
|
struct vir_region *r1, struct vir_region *r2)
|
|
{
|
|
return;
|
|
}
|