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Random number generator

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This commit is contained in:
Philip Homburg
2005-07-18 15:40:24 +00:00
parent 3eb405c3bf
commit 7d4e914618
20 changed files with 3739 additions and 36 deletions
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22
kernel/system.c
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@@ -273,11 +273,13 @@ int proc_nr; /* slot of process to clean up */
/*===========================================================================*
* get_randomness *
*===========================================================================*/
PUBLIC void get_randomness()
PUBLIC void get_randomness(source)
int source;
{
/* Gather random information with help of the CPU's cycle counter. Only use
* the lowest bytes because the highest bytes won't differ that much.
*/
int r_next;
unsigned long tsc_high;
/* On machines with the RDTSC (cycle counter read instruction - pentium
@@ -287,15 +289,17 @@ PUBLIC void get_randomness()
* Unfortunately this test is run-time - we don't want to bother with
* compiling different kernels for different machines..
*
* On machines without RDTSC, we use the get_uptime() - read_clock()
* has a higher resolution, but would involve I/O calls.
* On machines without RDTSC, we use read_clock().
*/
if (machine.processor > 486)
read_tsc(&tsc_high, &krandom.r_buf[krandom.r_next]);
source %= RANDOM_SOURCES;
r_next= krandom.bin[source].r_next;
if(machine.processor > 486 && 0)
read_tsc(&tsc_high, &krandom.bin[source].r_buf[r_next]);
else
krandom.r_buf[krandom.r_next] = get_uptime();
if (krandom.r_size < RANDOM_ELEMENTS) krandom.r_size ++;
krandom.r_next = (krandom.r_next + 1 ) % RANDOM_ELEMENTS;
krandom.bin[source].r_buf[r_next] = read_clock();
if (krandom.bin[source].r_size < RANDOM_ELEMENTS)
krandom.bin[source].r_size ++;
krandom.bin[source].r_next = (r_next + 1 ) % RANDOM_ELEMENTS;
}
@@ -313,7 +317,7 @@ irq_hook_t *hook;
/* As a side-effect, the interrupt handler gathers random information by
* timestamping the interrupt events. This is used for /dev/random.
*/
get_randomness();
get_randomness(hook->irq);
/* Add a bit for this interrupt to the process' pending interrupts. When
* sending the notification message, this bit map will be magically set