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vmm: Use the kernel's ELF file to map the sections (and now works!)

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This commit is contained in:
RaphProductions 2025-05-18 21:45:14 +02:00
parent 875dc2685b
commit c658f738e4
9 changed files with 250 additions and 59 deletions
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58
kernel/src/mm/vmm.c
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@ -5,12 +5,13 @@
* vmm.c - Virtual memory manager
*/
#include "boot/limine.h"
#include "lib/log.h"
#include <stdbool.h>
#include <stddef.h>
#include <arch/cpu.h>
#include <boot/limine.h>
#include <exec/elf.h>
#include <lib/log.h>
#include <mm/memop.h>
#include <mm/pmm.h>
#include <mm/vmm.h>
@ -31,36 +32,37 @@ void vmm_init() {
uint64_t kvaddr = limine_get_kernel_vaddr();
uint64_t kpaddr = limine_get_kernel_paddr();
uint64_t reqs_start = ALIGN_DOWN((uint64_t)reqs_start_ld, PMM_PAGE_SIZE);
uint64_t reqs_end = ALIGN_UP((uint64_t)reqs_end_ld, PMM_PAGE_SIZE);
uint64_t text_start = ALIGN_DOWN((uint64_t)text_start_ld, PMM_PAGE_SIZE);
uint64_t text_end = ALIGN_UP((uint64_t)text_end_ld, PMM_PAGE_SIZE);
uint64_t rodata_start = ALIGN_DOWN((uint64_t)rodata_start_ld, PMM_PAGE_SIZE);
uint64_t rodata_end = ALIGN_UP((uint64_t)rodata_end_ld, PMM_PAGE_SIZE);
uint64_t data_start = ALIGN_DOWN((uint64_t)data_start_ld, PMM_PAGE_SIZE);
uint64_t data_end = ALIGN_UP((uint64_t)data_end_ld, PMM_PAGE_SIZE);
char *elf_addr = (char *)limine_get_kernel_ehdr_addr();
Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elf_addr;
// Now, map the kernel's sections
for (uint64_t i = reqs_start; i < reqs_end; i += PMM_PAGE_SIZE)
vmm_map(vmm_kernel_pm, i, i - kvaddr + kpaddr, PTE_PRESENT | PTE_WRITE); // why would i write into Limine requests?
trace("vmm: Mapped limine rqs: PW\n");
for (uint64_t i = text_start; i < text_end; i += PMM_PAGE_SIZE)
vmm_map(vmm_kernel_pm, i, i - kvaddr + kpaddr, PTE_PRESENT);
trace("vmm: Mapped text: P\n");
for (uint64_t i = rodata_start; i < rodata_end; i += PMM_PAGE_SIZE)
vmm_map(vmm_kernel_pm, i, i - kvaddr + kpaddr, PTE_PRESENT | PTE_NX);
trace("vmm: Mapped rodata: P NX\n");
for (uint64_t i = data_start; i < data_end; i += PMM_PAGE_SIZE)
vmm_map(vmm_kernel_pm, i, i - kvaddr + kpaddr, PTE_PRESENT | PTE_WRITE | PTE_NX);
trace("vmm: Mapped data: PW NX\n");
for (uint16_t i = 0; i < ehdr->e_phnum; i++) {
Elf64_Phdr *cur_phdr = (Elf64_Phdr*)(elf_addr + ehdr->e_phoff + (i * ehdr->e_phentsize));
if (cur_phdr->p_type != PT_LOAD)
continue;
uintptr_t phys = (cur_phdr->p_vaddr - kvaddr) + kpaddr;
uint64_t flags = PTE_PRESENT;
if ((cur_phdr->p_flags & PF_X) == 0) {
flags |= PTE_NX;
}
if (cur_phdr->p_flags & PF_W) {
flags |= PTE_WRITE;
}
size_t length = ALIGN_UP(cur_phdr->p_memsz, PMM_PAGE_SIZE);
for (uint64_t i = 0; i < length; i += PMM_PAGE_SIZE) {
vmm_map(vmm_kernel_pm, cur_phdr->p_vaddr + i, phys + i, flags);
}
trace("vmm: Mapped range: %p -> %p (length: %x)\n", phys, cur_phdr->p_vaddr, length);
}
// Map the lower 4 GiB into the higher-half
for (uint64_t i = 0; i < 0x100000000; i += PMM_PAGE_SIZE)
vmm_map(vmm_kernel_pm, higher_half(i), i, PTE_PRESENT | PTE_WRITE);
trace("vmm: Mapped lower 4gib to higher half with flags: PW\n");
cpu_load_pm(vmm_kernel_pm);
trace("vmm: Mapped range: %p -> %p (length: %x)\n", 0x0, 0xFFFF800000000000, 0x100000000);
vmm_load_pm(vmm_kernel_pm);
trace("vmm: Initialized.\n");
}
@ -96,7 +98,6 @@ void vmm_free_pm(pagemap_t pm) {
static uint64_t *__vmm_get_next_lvl(uint64_t *level, uint64_t entry,
uint64_t flags, bool alloc) {
//trace("level: %p, level[entry]: %p\n", level, level + entry);
if (level[entry] & PTE_PRESENT)
return (uint64_t *)higher_half(PTE_GET_ADDR(level[entry]));
if (alloc) {
@ -111,7 +112,6 @@ static uint64_t *__vmm_get_next_lvl(uint64_t *level, uint64_t entry,
void vmm_map(pagemap_t pm, uint64_t vaddr, uint64_t paddr, uint64_t flags) {
if (!pm) return;
//trace("pm: %p, vaddr: %p, paddr: %p\n", pm, vaddr, paddr);
uint64_t pml4_entry = (vaddr >> 39) & 0x1ff;
uint64_t pml3_entry = (vaddr >> 30) & 0x1ff;
uint64_t pml2_entry = (vaddr >> 21) & 0x1ff;