mirror of https://github.com/tailix/kernel.git
112 lines
2.5 KiB
C
112 lines
2.5 KiB
C
#include "pfa.h"
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#include "config.h"
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#include "panic.h"
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#include "logger.h"
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#include <kernelmq/stdlib.h>
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#define FRAMES_COUNT (PAGE_DIR_LENGTH * PAGE_TABLE_LENGTH)
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static unsigned char frames[FRAMES_COUNT];
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static void mark_used(unsigned long base, unsigned long limit);
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void pfa_initialize(const struct KernelMQ_Info *const kinfo)
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{
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logger_info_from("pfa", "Initialize page frame allocator.");
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kmemset(frames, 0, sizeof(frames));
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mark_used(0, MEM_UPPER_BASE - 1);
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mark_used(kinfo->kernel_phys_base, kinfo->kernel_phys_limit);
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for (unsigned int i = 0; i < kinfo->modules_count; ++i) {
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const struct KernelMQ_Info_Module *const module = &kinfo->modules[i];
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mark_used(module->base, module->limit);
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}
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for (unsigned int i = 0; i < kinfo->areas_count; ++i) {
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const struct KernelMQ_Info_Area *const area = &kinfo->areas[i];
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if (!area->is_available) {
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mark_used(area->base, area->limit);
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}
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}
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}
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unsigned long pfa_alloc_page()
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{
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for (unsigned int i = 0; i < FRAMES_COUNT; ++i) {
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if (!frames[i]) {
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frames[i] = 0xFF;
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return i * PAGE_SIZE;
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}
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}
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return 0;
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}
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unsigned long pfa_alloc_big_page()
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{
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unsigned int start = 0;
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for (unsigned int i = 0; i < FRAMES_COUNT; ++i) {
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if (frames[i]) {
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start = i + 1;
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continue;
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}
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if (start % (PAGE_BIG_SIZE / PAGE_SIZE)) {
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continue;
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}
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if (i - start + 1 == PAGE_BIG_SIZE / PAGE_SIZE) {
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for (unsigned int j = start; j <= i; ++j) {
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frames[j] = 0xFF;
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}
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return start * PAGE_SIZE;
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}
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}
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return 0;
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}
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void pfa_free_page(const unsigned long base)
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{
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assert(!(base % PAGE_SIZE), "Small page address to free is not aligned.");
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const unsigned long i = base / PAGE_SIZE;
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if (i >= FRAMES_COUNT) {
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return;
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}
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frames[i] = 0;
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}
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void pfa_free_big_page(const unsigned long base)
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{
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assert(!(base % PAGE_BIG_SIZE), "Big page address to free is not aligned.");
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const unsigned long start = base / PAGE_SIZE;
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const unsigned long end = start + PAGE_BIG_SIZE / PAGE_SIZE;
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for (unsigned int i = start; i <= end && i < FRAMES_COUNT; ++i) {
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frames[i] = 0;
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}
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}
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void mark_used(const unsigned long base, const unsigned long limit)
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{
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const unsigned int start = base / PAGE_SIZE;
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const unsigned int end = limit / PAGE_SIZE;
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for (unsigned int i = start; i <= end; ++i) {
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frames[i] = 0xFF;
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}
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}
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