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/* 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 *state,
int len, int *io);
static int anon_sanitycheck(struct phys_region *pr, const 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);
static int anon_pt_flags(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,
.pt_flags = anon_pt_flags,
};
static int anon_pt_flags(struct vir_region *vr){
#if defined(__arm__)
return ARM_VM_PTE_CACHED;
#else
return 0;
#endif
}
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 *state,
int len, int *io)
{
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) {
/* memory is ready already */
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, const 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;
}
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