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#include <stdint.h>
#include <kernel/paging/paging.h>
#include <kernel/system.h>
uint32_t page_directory[1024] __attribute__((aligned(4096)));
uint32_t page_tables[1024][1024] __attribute__((aligned(4096)));
void paging_install() {
for (uint32_t i = 0; i < 1024; i++) {
for (uint32_t j = 0; j < 1024; j++) {
page_tables[i][j] = ((j * 0x1000) + (i * 0x400000)) | PT_RW;
}
}
for (uint32_t i = 0; i < 1024; i++) {
page_directory[i] = ((uint32_t) page_tables[i]) | PD_RW | PD_PRESENT;
}
// TODO: Calculate max memory
paging_set_present(0, 0x1000000);
paging_set_used(0, ((uint32_t) end >> 12) + 1);
paging_enable();
vga_log("Installed paging", 4);
}
int paging_enabled() {
uint32_t cr0;
asm volatile("mov %%cr0, %0": "=r"(cr0));
return (cr0 | 0x80000000) == cr0;
}
void paging_disable() {
uint32_t cr0;
asm volatile("mov %%cr0, %0": "=r"(cr0));
cr0 &= 0x7fffffff;
asm volatile("mov %0, %%cr0"::"r"(cr0));
}
void paging_enable() {
asm volatile("mov %0, %%cr3"::"r"(page_directory));
uint32_t cr0;
asm volatile("mov %%cr0, %0": "=r"(cr0));
cr0 |= 0x80000000;
asm volatile("mov %0, %%cr0"::"r"(cr0));
}
inline void invlpg(uint32_t addr) {
asm volatile("invlpg (%0)"::"r" (addr) : "memory");
}
void paging_map(uint32_t phy, uint32_t virt, uint16_t flags) {
uint32_t pdi = virt >> 22;
uint32_t pti = virt >> 12 & 0x03FF;
page_tables[pdi][pti] = phy | flags;
invlpg(virt);
}
uint32_t paging_get_physical_addr(uint32_t virt) {
uint32_t pdi = virt >> 22;
uint32_t pti = (virt >> 12) & 0x03FF;
return page_tables[pdi][pti] & 0xFFFFF000;
}
uint16_t paging_get_flags(uint32_t virt) {
uint32_t pdi = virt >> 22;
uint32_t pti = (virt >> 12) & 0x03FF;
return page_tables[pdi][pti] & 0xFFF;
}
void paging_set_flag_up(uint32_t virt, uint32_t count, uint32_t flag) {
uint32_t page_n = virt / 4096;
for (uint32_t i = page_n; i < page_n + count; i++) {
page_tables[i / 1024][i % 1024] |= flag;
invlpg(i * 4096);
}
}
void paging_set_flag_down(uint32_t virt, uint32_t count, uint32_t flag) {
uint32_t page_n = virt / 4096;
for (uint32_t i = page_n; i < page_n + count; i++) {
page_tables[i / 1024][i % 1024] &= ~flag;
invlpg(i * 4096);
}
}
void paging_set_present(uint32_t virt, uint32_t count) {
paging_set_flag_up(virt, count, PT_PRESENT);
}
void paging_set_absent(uint32_t virt, uint32_t count) {
paging_set_flag_down(virt, count, PT_PRESENT);
}
void paging_set_used(uint32_t virt, uint32_t count) {
paging_set_flag_up(virt, count, PT_USED);
}
void paging_set_free(uint32_t virt, uint32_t count) {
paging_set_flag_down(virt, count, PT_USED);
}
void paging_set_user(uint32_t virt, uint32_t count) {
uint32_t page_n = virt / 4096;
for (uint32_t i = page_n; i < page_n + count; i += 1024) {
page_directory[i / 1024] |= PD_ALL_PRIV;
}
paging_set_flag_up(virt, count, PT_ALL_PRIV);
}
uint32_t paging_find_pages(uint32_t count) {
uint32_t continous = 0;
uint32_t startDir = 0;
uint32_t startPage = 0;
for (uint32_t i = 0; i < 1024; i++) {
for (uint32_t j = 0; j < 1024; j++) {
if (!(page_tables[i][j] & PT_PRESENT) || (page_tables[i][j] & PT_USED)) {
continous = 0;
startDir = i;
startPage = j + 1;
} else {
if (++continous == count)
return (startDir * 0x400000) + (startPage * 0x1000);
}
}
}
panic("Out of memory!");
return 0;
}
uint32_t paging_alloc_pages(uint32_t count) {
uint32_t ptr = paging_find_pages(count);
paging_set_used(ptr, count);
return ptr;
}
uint32_t paging_get_used_pages() {
uint32_t n = 0;
for (uint32_t i = 0; i < 1024; i++) {
for (uint32_t j = 0; j < 1024; j++) {
uint8_t flags = page_tables[i][j] & PT_USED;
if (flags == 1) n++;
}
}
return n;
}
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