717425320f
kernel: stop gathering timestamps once the bin is full per interrupt random: once seeded, retrieve new entropy at a lower rate Change-Id: I4ce6081d39274728d82c6889686d1650cfd5fc2e
36 lines
1.0 KiB
C
36 lines
1.0 KiB
C
#include <lib.h>
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <minix/profile.h>
|
|
#include <minix/syslib.h>
|
|
#include <minix/type.h>
|
|
#include <minix/minlib.h>
|
|
#include <minix/sysutil.h>
|
|
|
|
/*===========================================================================*
|
|
* get_randomness *
|
|
*===========================================================================*/
|
|
void get_randomness(rand, source)
|
|
struct k_randomness *rand;
|
|
int source;
|
|
{
|
|
/* Use architecture-dependent high-resolution clock for
|
|
* raw entropy gathering.
|
|
*/
|
|
int r_next;
|
|
unsigned long tsc_high, tsc_low;
|
|
|
|
source %= RANDOM_SOURCES;
|
|
if (rand->bin[source].r_size >= RANDOM_ELEMENTS) return;
|
|
r_next= rand->bin[source].r_next;
|
|
read_tsc((u32_t *) &tsc_high, (u32_t *) &tsc_low);
|
|
rand->bin[source].r_buf[r_next] = tsc_low;
|
|
if (rand->bin[source].r_size < RANDOM_ELEMENTS) {
|
|
rand->bin[source].r_size ++;
|
|
}
|
|
rand->bin[source].r_next = (r_next + 1 ) % RANDOM_ELEMENTS;
|
|
}
|
|
|
|
|