diff options
Diffstat (limited to 'mem/buddymap.c')
| -rw-r--r-- | mem/buddymap.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/mem/buddymap.c b/mem/buddymap.c new file mode 100644 index 0000000..5165876 --- /dev/null +++ b/mem/buddymap.c @@ -0,0 +1,151 @@ +#include "buddymap.h" +#include "lib/string.h" +#include "boot/boot.h" +#include "io/log.h" +#include <stdbool.h> + +#define ENTRY_BITS (sizeof(uintmax_t) * 8) +#define ENTRY_SIZE (ENTRY_BITS * PAGESIZE) +#define ENTRY_COUNT (MEMMAP_BUDDY_LIMIT / ENTRY_SIZE) +#define BUDDY_LAYERS 4 + +uintmax_t s_buddy_l0[ENTRY_COUNT]; +uintmax_t s_buddy_l1[ENTRY_COUNT << 1]; +uintmax_t s_buddy_l2[ENTRY_COUNT << 2]; +uintmax_t s_buddy_l3[ENTRY_COUNT << 3]; +uintmax_t *s_buddies[BUDDY_LAYERS] = { + s_buddy_l0, + s_buddy_l1, + s_buddy_l2, + s_buddy_l3 +}; +size_t s_buddies_lastfree[BUDDY_LAYERS] = { 1, 1, 1, 1 }; + +static bool +s_buddy_test(size_t l, size_t i) +{ + return (s_buddies[l][i / (ENTRY_BITS)] & (1ULL << (i % (ENTRY_BITS)))) > 0; +} + +static void +s_buddy_set(size_t l, size_t i) +{ + size_t j = i << l; + size_t w = 1 << l; + for(int layer = 0; layer < BUDDY_LAYERS; layer++) + { + if(w == 0) w = 1; + for(size_t bit = 0; bit < w; bit++) { + size_t entry = (j + bit) / ENTRY_BITS; + s_buddies[layer][entry] |= (1ULL << (j + bit % ENTRY_BITS)); + } + j >>= 1; + w >>= 1; + } +} + +static void +s_buddy_unset(size_t l, size_t i) +{ + size_t j = i << l; + size_t w = 1 << l; + bool free_upper = false; + for(int layer = 0; layer < BUDDY_LAYERS; layer++) + { + if(w == 0) { + size_t lower = (j << 1) % ENTRY_BITS; + size_t other = (lower + 1); + size_t entry = (j << 1) / ENTRY_BITS; + if((s_buddies[layer-1][entry] & (1ULL << lower)) > 0 && + (s_buddies[layer-1][entry] & (1ULL << other)) > 0) + s_buddies[layer][entry >> 1] &= ~(1ULL << (j % ENTRY_BITS)); + } + + for(size_t bit = 0; bit < w; bit++) { + size_t entry = j / ENTRY_BITS; + s_buddies[layer][entry] |= (1ULL << bit); + } + j >>= 1; + w >>= 1; + } +} + +void +mem_buddy_set_range(uintptr_t base, size_t length) +{ + for(int l = 0; l < BUDDY_LAYERS; l++) { + size_t bits = (length / PAGESIZE) >> l; + size_t biti = (base / PAGESIZE) >> l; + + if(bits == 0) bits = 1; + for(size_t i = 0; i < bits; i++) { + size_t entry = (biti + i) / ENTRY_BITS; + s_buddies[l][entry] |= 1ULL << ((biti + i) % ENTRY_BITS); + } + } +} + +void +mem_buddy_free_range(uintptr_t base, size_t length) +{ + for(int l = 0; l < BUDDY_LAYERS; l++) { + size_t bits = (length / PAGESIZE) >> l; + size_t biti = (base / PAGESIZE) >> l; + size_t bitbase = (biti * PAGESIZE) << l; + + if(bits == 0) continue; + for(size_t i = 0; i < bits; i++, bitbase += (PAGESIZE << l)) { + if(bitbase < base) continue; + size_t entry = (biti + i) / ENTRY_BITS; + s_buddies[l][entry] &= ~(1ULL << ((biti+ i) % ENTRY_BITS)); + } + } +} + + +uintptr_t +mem_buddy_takefree(size_t l) +{ + uintmax_t *layer = s_buddies[l]; + size_t lastfree = s_buddies_lastfree[l]; + if(s_buddy_test(l, lastfree)) lastfree = 0; + size_t entries = ENTRY_COUNT >> l; + for(size_t i = lastfree / ENTRY_BITS; i < entries; i++) { + uintmax_t entry = layer[i]; + if(entry == (uintmax_t)-1LL) continue; + for(size_t j = 0; j < ENTRY_BITS; j++) { + if((entry & (1ULL << j)) == 0) { + size_t bit = (i * ENTRY_BITS) + j; + s_buddies_lastfree[l] = bit + 1; + s_buddy_set(l, bit); + return bit * (PAGESIZE << l); + } + } + } + return 0; +} + +void +mem_buddy_setup() +{ + memset(s_buddy_l0, 0xFF, sizeof(s_buddy_l0)); + memset(s_buddy_l1, 0xFF, sizeof(s_buddy_l1)); + memset(s_buddy_l2, 0xFF, sizeof(s_buddy_l2)); + memset(s_buddy_l3, 0xFF, sizeof(s_buddy_l3)); + + for(int i = 0; i < boot_memorymap.count; i++) { + struct MemoryMapEntry *entry = &boot_memorymap.entries[i]; + klogf("%2i\t%#016X -> %#016X (%i)\n", + i, entry->base, entry->base + entry->length, entry->usable); + if(entry->base > MEMMAP_BUDDY_LIMIT) continue; + size_t length = entry->length; + if(entry->base + length > MEMMAP_BUDDY_LIMIT) length = MEMMAP_BUDDY_LIMIT - (entry->base + length); + if(entry->usable) + mem_buddy_free_range(entry->base, entry->length); + } + + s_buddies[0][0] |= 1; + s_buddies[1][0] |= 1; + s_buddies[2][0] |= 1; + s_buddies[3][0] |= 1; +} |