rulimine/common/mm/pmm.c

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#include <mm/pmm.h>
#include <lib/rand.h>
#include <lib/print.h>
void pmm_randomise_memory(void) {
print("pmm: Randomising memory contents...");
for (size_t i = 0; i < memmap_entries; i++) {
if (memmap[i].type != MEMMAP_USABLE)
continue;
#if defined (BIOS)
// We're not going to randomise memory above 4GiB from protected mode,
// are we?
if (memmap[i].base >= 0x100000000) {
continue;
}
#endif
uint8_t *ptr = (void *)(uintptr_t)memmap[i].base;
size_t len = memmap[i].length;
for (size_t j = 0;;) {
uint32_t random = rand32();
uint8_t *rnd_data = (void *)&random;
if (j >= len)
break;
ptr[j++] = rnd_data[0];
if (j >= len)
break;
ptr[j++] = rnd_data[1];
if (j >= len)
break;
ptr[j++] = rnd_data[2];
if (j >= len)
break;
ptr[j++] = rnd_data[3];
}
}
print("\n");
}