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vmm bullshit

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PoliEcho
2026-09-27 15:10:18 +02:00
parent 318fe96319
commit 6c609e9840
3 changed files with 93 additions and 26 deletions
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kernel/include/vmm.h
+9
View File
@@ -0,0 +1,9 @@
#ifndef _VMM_H
#define _VMM_H
#include "types.h"
#define CANONICAL_MASK_KERNEL 0xFFFF800000000000
#define CANONICAL_MASK_USER 0x00007FFFFFFFFFF000
int vmm_alloc(void** vaddr, uint64_t count, uint64_t flags);
#endif
kernel/src/kmain.c
+47 -17
View File
@@ -1,23 +1,28 @@
#include "errno.h"
#include "types.h"
#include <bootloader.h>
#include <kernel.h>
#include <paging.h>
#include <serial.h>
#include <random.h>
#include <splash.h>
#include <system.h>
#include <gdt.h>
#include <isr.h>
#include <kernel.h>
#include <paging.h>
#include <pmm.h>
#include <random.h>
#include <serial.h>
#include <splash.h>
#include <string.h>
#include <system.h>
#include <vmm.h>
__noreturn
void _start(void) {
__noreturn void _start(void) {
int err = 0;
// Serial console for debugging
if ((err = serial_init(COM1)) < 0) panic(NULL, "Failed to initialize Serial driver. (%d)", err);
if ((err = serial_init(COM1)) < 0)
panic(NULL, "Failed to initialize Serial driver. (%d)", err);
// Load structures from bootloader
if ((err = boot_init()) < 0) panic(NULL, "Failed to parse bootloader structures. (%d)", err);
if ((err = boot_init()) < 0)
panic(NULL, "Failed to parse bootloader structures. (%d)", err);
// CPUID thingy :p
uint32_t eax = 0;
@@ -26,26 +31,51 @@ void _start(void) {
pr_info("[kernel] CPUID_GETVENDORID: %s\n", s);
// System init
if ((err = gdt_init()) < 0) panic(NULL, "Failed to initalize GDT. (%d)", err);
if ((err = isr_init()) < 0) panic(NULL, "Failed to initalize ISRs. (%d)", err);
if ((err = gdt_init()) < 0)
panic(NULL, "Failed to initalize GDT. (%d)", err);
if ((err = isr_init()) < 0)
panic(NULL, "Failed to initalize ISRs. (%d)", err);
// Memory management
if ((err = pmm_init()) < 0) panic(NULL, "Failed to initalize Physical Memory Manager. (%d)", err);
if ((err = pag_init()) < 0) panic(NULL, "Failed to initalize Paging. (%d)", err);
if ((err = pmm_init()) < 0)
panic(NULL, "Failed to initalize Physical Memory Manager. (%d)",
err);
if ((err = pag_init()) < 0)
panic(NULL, "Failed to initalize Paging. (%d)", err);
// random number generation
rand_init();
// test random number generation
printk("Random number generation test:\n");
for (uint8_t i = 0; i <= 16; i++) {
printk("%d: %lu\n",i,get_random_number());
printk("%d: %lu\n", i, get_random_number());
}
// test VMM
{
void* vaddr;
int ret = vmm_alloc(&vaddr, 2, 0);
if (ret != SUCCESS) {
panic(NULL, "vmm_alloc returned %d", ret);
}
{
uint64_t* pml4 = pag_get_pml4();
uint64_t* pte = pag_get_pte(pml4, vaddr);
if (!IS_ERR(pte) && (*pte & PTE_FLAG_PRESENT)) {
printk("page allocated\n");
} else {
printk("page not allocated\n");
}
}
memset(vaddr, 69, 2 * PAGE_SIZE);
*(char*)((vaddr + (2 * PAGE_SIZE)) - 1) = 0;
printk("read back:\n%s\n", (char*)vaddr);
}
// The most important function in the world.
splash();
// Patiently wait for things to do :)
while (1);
while (1)
;
};
kernel/src/vmm.c
+37 -9
View File
@@ -1,9 +1,11 @@
#include "vmm.h"
#include "kernel.h"
#include <errno.h>
#include <isr.h>
#include <limits.h>
#include <paging.h>
#include <pmm.h>
#include <random.h>
#include <types.h>
// allocates set number of pages at address provided
@@ -12,27 +14,53 @@ int vmm_alloc(void** vaddr, uint64_t count, uint64_t flags) {
if (flags == 0) {
flags = PTE_FLAG_PRESENT | PTE_FLAG_WRITE | PTE_FLAG_NOEXEC;
}
bool random_vaddr = *vaddr ? false : true;
uint64_t* pml4 = pag_get_pml4();
for (uint64_t i = 0; i < count; i++) {
uint64_t* pte = pag_get_pte(pml4, vaddr);
if (!IS_ERR(pte) && (*pte & PTE_FLAG_PRESENT)) {
// TODO actualy handle conflict
return EEXIST;
{
uint8_t limit_counter = 0;
while (true) {
if (random_vaddr) {
retry_selection:
*vaddr = (void*)ALIGN_DOWN(get_random_number(),
PAGE_SIZE);
*vaddr = (void*)((uint64_t)(*vaddr) &
CANONICAL_MASK_USER);
if (!(flags & PTE_FLAG_USER)) {
*vaddr = (void*)((uint64_t)(*vaddr) |
CANONICAL_MASK_KERNEL);
}
}
for (uint64_t i = 0; i < count; i++) {
uint64_t* pte =
pag_get_pte(pml4, *vaddr + (i * PAGE_SIZE));
if (!IS_ERR(pte) && (*pte & PTE_FLAG_PRESENT)) {
if (!random_vaddr) {
return -EEXIST;
} else {
if (limit_counter < UINT8_MAX) {
goto retry_selection;
} else {
return -EAGAIN;
}
}
}
}
break;
}
}
for (uint64_t i = 0; i < count; i++) {
void* paddr = pmm_alloc();
int pag_map_ret =
pag_map(pml4, (void*)(((size_t)vaddr) * i * PAGE_SIZE),
paddr, flags);
pag_map(pml4, *vaddr + (i * PAGE_SIZE), paddr, flags);
if (pag_map_ret != SUCCESS) {
if (i != 0) {
for (i -= 1; i != UINT64_MAX; i--) {
if (pag_unmap(pml4,
(void*)(((size_t)vaddr) *
i * PAGE_SIZE)) !=
*vaddr +
(i * PAGE_SIZE)) !=
SUCCESS) {
panic(NULL,
"failed to unmap "