rulimine/common/lib/elsewhere.c

97 lines
2.8 KiB
C

#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <lib/elsewhere.h>
#include <lib/misc.h>
#include <mm/pmm.h>
static bool elsewhere_overlap_check(uint64_t base1, uint64_t top1,
uint64_t base2, uint64_t top2) {
return ((base1 >= base2 && base1 < top2)
|| (top1 > base2 && top1 <= top2));
}
bool elsewhere_append(
bool flexible_target,
struct elsewhere_range *ranges, uint64_t *ranges_count,
void *elsewhere, uint64_t *target, size_t t_length) {
// original target of -1 means "allocate after top of all ranges"
// flexible target is ignored
flexible_target = true;
if (*target == (uint64_t)-1) {
uint64_t top = 0;
for (size_t i = 0; i < *ranges_count; i++) {
uint64_t r_top = ranges[i].target + ranges[i].length;
if (top < r_top) {
top = r_top;
}
}
*target = ALIGN_UP(top, 4096);
}
uint64_t max_retries = 0x10000;
retry:
if (max_retries-- == 0) {
return false;
}
for (size_t i = 0; i < *ranges_count; i++) {
uint64_t t_top = *target + t_length;
// Does it overlap with other elsewhere ranges targets?
{
uint64_t base = ranges[i].target;
uint64_t length = ranges[i].length;
uint64_t top = base + length;
if (elsewhere_overlap_check(base, top, *target, t_top)) {
if (!flexible_target) {
return false;
}
*target = ALIGN_UP(top, 4096);
goto retry;
}
}
// Does it overlap with other elsewhere ranges sources?
{
uint64_t base = ranges[i].elsewhere;
uint64_t length = ranges[i].length;
uint64_t top = base + length;
if (elsewhere_overlap_check(base, top, *target, t_top)) {
if (!flexible_target) {
return false;
}
*target += 0x1000;
goto retry;
}
}
// Make sure it is memory that actually exists.
if (!memmap_alloc_range(*target, t_length, MEMMAP_BOOTLOADER_RECLAIMABLE,
MEMMAP_USABLE, false, true, false)) {
if (!memmap_alloc_range(*target, t_length, MEMMAP_BOOTLOADER_RECLAIMABLE,
MEMMAP_BOOTLOADER_RECLAIMABLE, false, true, false)) {
if (!flexible_target) {
return false;
}
*target += 0x1000;
goto retry;
}
}
}
// Add the elsewhere range
ranges[*ranges_count].elsewhere = (uintptr_t)elsewhere;
ranges[*ranges_count].target = *target;
ranges[*ranges_count].length = t_length;
*ranges_count += 1;
return true;
}