78 lines
1.6 KiB
C
78 lines
1.6 KiB
C
#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include "assert.h"
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#include "kprintf.h"
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#include "memory.h"
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#include "process.h"
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#include "string.h"
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#include "utils.h"
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static int8_t alloc_pagetable(uint16_t pd_index)
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{
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uint32_t *pt = alloc_frame();
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if (!pt)
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return -1;
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PD[pd_index] = (uint32_t)pt | INIT_FLAGS;
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bzero(PTE2VA(1023, pd_index), PAGE_SIZE);
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return 0;
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}
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static uint32_t *find_next_block(size_t nb_pages)
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{
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size_t count = 0;
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for (size_t i = USER_PT_START; i < USER_PT_END; i++) {
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if (!PD[i])
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if (alloc_pagetable(i) < 0)
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return NULL;
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for (size_t j = 0; j < 1024; j++) {
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if (*GET_PTE(i, j)) {
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count = 0;
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continue;
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}
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count++;
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if (count == nb_pages) {
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return GET_PTE(i, j) - (count - 1);
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}
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}
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}
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return NULL;
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}
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void *valloc_pages(size_t nb_pages)
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{
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uint32_t *start = find_next_block(nb_pages);
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if (!start)
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return NULL;
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for (uint32_t i = 0; i < nb_pages; i++) {
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void *frame = alloc_frame();
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if (!frame) {
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for (uint32_t j = 0; j < i; j++)
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free_frame((void *)(((uint32_t)(start + j)) &
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PAGE_MASK));
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return NULL;
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}
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assert((uint32_t)frame & PAGE_MASK);
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start[i] = (uint32_t)frame | INIT_FLAGS;
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}
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uint32_t page_index = start - PTE2VA(1023, 0);
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return PTE2VA(page_index / 1024, page_index % 1024);
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}
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int vfree_pages(void *page_ptr, size_t nb_pages)
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{
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const uint32_t page_addr = (uint32_t)page_ptr;
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if (page_addr % PAGE_SIZE) {
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kprintf(KERN_WARNING "Invalid address\n");
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return -1;
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}
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for (uint32_t *pte = VA2PTE(page_addr);
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pte < VA2PTE(page_addr) + nb_pages; pte++) {
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free_frame((void *)(*pte & PAGE_MASK));
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*pte = 0;
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}
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return 0;
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}
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