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/*
* Routines to fault-in mapped pages.
*/
#include "arch.h"
#include "maps.h"
#include "random.h"
#include "utils.h"
static unsigned int nr_pages(struct map *map)
{
return map->size / page_size;
}
static void read_one_page(struct map *map)
{
char *p = map->ptr;
unsigned long offset = (rnd() % map->size) & PAGE_MASK;
char buf[page_size];
p += offset;
mprotect((void *) p, page_size, PROT_READ);
memcpy(buf, p, page_size);
}
static void read_whole_mapping(struct map *map)
{
char *p = map->ptr;
unsigned int i, nr;
char buf[page_size];
nr = nr_pages(map);
for (i = 0; i < nr; i++) {
char *page = p + (i * page_size);
mprotect((void *) page, page_size, PROT_READ);
memcpy(buf, page, page_size);
}
}
static void read_every_other_page(struct map *map)
{
char *p = map->ptr;
unsigned int i, nr, first;
char buf[page_size];
nr = nr_pages(map);
first = RAND_BOOL();
for (i = first; i < nr; i+=2) {
char *page = p + (i * page_size);
mprotect((void *) page, page_size, PROT_READ);
memcpy(buf, page, page_size);
}
}
static void read_mapping_reverse(struct map *map)
{
char *p = map->ptr;
unsigned int i, nr;
char buf[page_size];
nr = nr_pages(map) - 1;
for (i = nr; i > 0; i--) {
char *page = p + (i * page_size);
mprotect((void *) page, page_size, PROT_READ);
memcpy(buf, page, page_size);
}
}
/* fault in a random set of map->size pages. (some may be faulted >once) */
static void read_random_pages(struct map *map)
{
char *p = map->ptr;
unsigned int i, nr;
char buf[page_size];
nr = nr_pages(map);
for (i = 0; i < nr; i++) {
char *page = p + ((rnd() % nr) * page_size);
mprotect((void *) page, page_size, PROT_READ);
memcpy(buf, page, page_size);
}
}
/* Fault in the last page in a mapping */
static void read_last_page(struct map *map)
{
char *p = map->ptr;
char buf[page_size];
char *ptr;
ptr = p + (map->size - page_size);
mprotect((void *) ptr, page_size, PROT_READ);
memcpy(buf, ptr, page_size);
}
static const struct faultfn read_faultfns[] = {
{ .func = read_whole_mapping },
{ .func = read_every_other_page },
{ .func = read_mapping_reverse },
{ .func = read_random_pages },
{ .func = read_last_page },
};
void random_map_readfn(struct map *map)
{
if (map->size == page_size)
read_one_page(map);
else {
if (RAND_BOOL())
read_one_page(map);
else
read_faultfns[rnd() % ARRAY_SIZE(read_faultfns)].func(map);
}
}
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