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wip: user allocator

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0x35c
2025-11-28 17:36:10 +01:00
parent c6a5bf25c2
commit 3df6011d7a
7 changed files with 79 additions and 82 deletions
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136
src/memory/virt/page.c
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@ -9,82 +9,68 @@
#include "string.h"
#include "utils.h"
static int16_t find_next_block(size_t nb_pages, uint16_t *pd_index_ptr,
uint32_t **page_table_ptr)
static int8_t alloc_pagetable(uint16_t pd_index)
{
for (*pd_index_ptr = 2; *pd_index_ptr < 768; (*pd_index_ptr)++) {
// if (current_pd[(*pd_index_ptr)] == 0x02) {
// if (add_page_table(*pd_index_ptr, 1) < 0)
// return -2;
// }
*page_table_ptr = (uint32_t *)PTE2VA(1, *pd_index_ptr);
for (uint16_t i = 0; i + nb_pages - 1 < 1024; i++) {
uint16_t j;
for (j = 0; (*page_table_ptr)[i + j] >> 12 == i + j &&
j < nb_pages;
j++)
;
if (j == nb_pages)
return i;
i += j;
}
}
return -1;
}
void *valloc_pages(size_t size, void **phys_addr)
{
const uint32_t nb_pages = CEIL(size, PAGE_SIZE);
uint16_t pd_index;
uint32_t *page_table;
const int16_t index = find_next_block(nb_pages, &pd_index, &page_table);
if (index < 0) {
kprintf(KERN_CRIT "%d: Not enough pages (max: %d)\n", index,
1024);
return NULL;
}
for (size_t i = index; i - (size_t)index < nb_pages; i++) {
void *frame = alloc_frame();
if (!frame) {
for (size_t j = index; j < i; j++)
free_frame((void *)(page_table[j] & PAGE_MASK));
return NULL;
}
if (phys_addr)
*phys_addr = frame;
page_table[i] = ((uint32_t)frame & PAGE_MASK) | INIT_FLAGS;
}
return (void *)PTE2VA(pd_index, index);
}
int vfree_pages(void *page_ptr, size_t size)
{
const uint32_t page_addr = (uint32_t)page_ptr;
const uint32_t nb_pages = CEIL(size, PAGE_SIZE);
const uint32_t page_index = page_addr / PAGE_SIZE;
const uint32_t pd_index = page_index / 1024;
const uint32_t pt_index = page_index % 1024;
if ((uint32_t)pd_index > 0x300) {
kprintf(KERN_WARNING "Address out of range\n");
uint32_t *pt = alloc_frame();
if (!pt)
return -1;
} else if (page_addr % PAGE_SIZE) {
kprintf(KERN_WARNING "Invalid address\n");
return -1;
} else if (pt_index + nb_pages > 1024) {
kprintf(KERN_WARNING "Invalid number of frames\n");
return -1;
}
uint32_t *page_table = (uint32_t *)PTE2VA(1, pd_index);
for (uint16_t i = pt_index; i < pt_index + nb_pages; i++) {
if (page_table[i] >> 12 == i) {
kprintf(KERN_WARNING "Page already freed\n");
return -2;
}
free_frame((void *)(page_table[i] & PAGE_MASK));
page_table[i] = i << 12;
}
PD[pd_index] = (uint32_t)pt | INIT_FLAGS;
return 0;
}
static uint32_t *find_next_block(size_t nb_pages)
{
size_t count = 0;
for (size_t i = USER_PT_START; i < USER_PT_END; i++) {
if (!PD[i])
if (alloc_pagetable(i) < 0)
return NULL;
for (size_t j = 0; j < 1024; j++) {
if (!*GET_PTE(i, j)) {
count = 0;
continue;
}
count++;
if (count == nb_pages) {
return GET_PTE(i, j) - count;
}
}
}
return NULL;
}
void *valloc_pages(size_t nb_pages)
{
uint32_t *start = find_next_block(nb_pages);
if (!start)
return NULL;
for (uint32_t i = 0; i < nb_pages; i++) {
void *frame = alloc_frame();
if (!frame) {
for (uint32_t j = 0; j < i; j++)
free_frame((void *)(((uint32_t)(start + j)) &
PAGE_MASK));
return NULL;
}
assert((uint32_t)frame & PAGE_MASK);
start[i] = (uint32_t)frame | INIT_FLAGS;
}
uint32_t page_index = start - PTE2VA(1023, 0);
return PTE2VA(page_index / 1024, page_index % 1024);
}
int vfree_pages(void *page_ptr, size_t nb_pages)
{
const uint32_t page_addr = (uint32_t)page_ptr;
if (page_addr % PAGE_SIZE) {
kprintf(KERN_WARNING "Invalid address\n");
return -1;
}
for (uint32_t *pte = VA2PTE(page_addr);
pte < VA2PTE(page_addr) + nb_pages; pte++) {
free_frame((void *)(*pte & PAGE_MASK));
*pte = 0;
}
return 0;
}