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Merged
mebrahimaleem merged 4 commits into from
Feb 15, 2026
Merged

Preemptive Multitasking #5

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ab9f6b5
minimal slab allocator
mebrahimaleem Feb 11, 2026
9fe73da
ap bootstrap
mebrahimaleem Feb 11, 2026
5b9a238
ap init
mebrahimaleem Feb 11, 2026
ee7b08f
preemptive scheduler
mebrahimaleem Feb 15, 2026
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2 changes: 1 addition & 1 deletion Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@
# Debug options

#export DEBUG = 1
#export DEBUG_LOGGING = 1
export DEBUG_LOGGING = 1

# Global options

Expand Down
47 changes: 31 additions & 16 deletions boot/multiboot2/boot.S
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Original file line number Diff line number Diff line change
Expand Up @@ -56,17 +56,11 @@
#define LME 0x100
#define PG (1 << 31)

#define GDT_RW (1 << 1)
#define GDT_E (1 << 3)
#define GDT_S (1 << 4)
#define GDT_P (1 << 7)
#define GDT_L (1 << 5)
#define GDT_G (1 << 7)

#define KERNEL_PAGE_FLAGS (1 + 2)
#define PAGE_SZ (1 << 7)

#define PAGING_1GIB 0x40000000
#define IDENT_BASE 0xFFFFFF0000000000

.code32
.section .text.multiboot2
Expand Down Expand Up @@ -230,7 +224,8 @@ enter64:

.section .text
ktransfer:
addq $KERNEL_VMA, gdt_ptr64.addr
movq $IDENT_BASE, %rax
addq %rax, gdt_ptr64.addr
lgdt gdt_ptr64
addq $KERNEL_VMA, %rsp
pushq $0
Expand All @@ -250,24 +245,36 @@ gdt:
.short 0x0000 /* limit 0:15 */
.short 0x0000 /* base 0:15 */
.byte 0x00 /* base 16:23 */
.byte GDT_RW + GDT_E + GDT_S + GDT_P /* access: RW E S P */
.byte GDT_L + GDT_G /* limit 16:19 flag: L G */
.byte 0x98 /* access: DPL=0 P */
.byte 0x20 /* limit 16:19 flag: L */
.byte 0x00 /* base 24:31 */
gdt.dataseg:
.short 0x0000 /* limit 0:15 */
.short 0x0000 /* base 0:15 */
.byte 0x00 /* base 16:23 */
.byte GDT_RW + GDT_S + GDT_P /* access: RW S P */
.byte GDT_G /* limit 16:19 flag: G */
.byte 0x92 /* access: RW S P */
.byte 0x92 /* access: P */
.byte 0x00 /* limit 16:19 flag: */
.byte 0x00 /* base 24:31 */
gdt.ucodeseg:
.quad 0
.short 0x0000 /* limit 0:15 */
.short 0x0000 /* base 0:15 */
.byte 0x00 /* base 16:23 */
.byte 0xF8 /* access: DPL=3 P */
.byte 0x20 /* limit 16:19 flag: L */
.byte 0x00 /* base 24:31 */
gdt.udataseg:
.quad 0
.short 0x0000 /* limit 0:15 */
.short 0x0000 /* base 0:15 */
.byte 0x00 /* base 16:23 */
.byte 0x92 /* access: P */
.byte 0x00 /* limit 16:19 flag: */
.byte 0x00 /* base 24:31 */
gdt.tss:
.quad 0
.quad 0
gdt.end:
.globl gdt_end
gdt_end:

.equ CODE_SEG, gdt.codeseg - gdt
.equ DATA_SEG, gdt.dataseg - gdt
Expand All @@ -288,9 +295,10 @@ gdt_ptr64.addr:
kernel_pml4:
PML4:
.quad PDPT_0 + KERNEL_PAGE_FLAGS
.rept 0x200 - 2
.rept 0x200 - 3
.quad 0
.endr
.quad PDPT_510 + KERNEL_PAGE_FLAGS
.quad PDPT_511 + KERNEL_PAGE_FLAGS

PDPT_0:
Expand All @@ -300,6 +308,13 @@ PDPT_0:
.quad 0
.endr

PDPT_510:
.set i, 0
.rept 0x200
.quad (i * PAGING_1GIB) + KERNEL_PAGE_FLAGS + PAGE_SZ
.set i, i+1
.endr

PDPT_511:
.rept 0x200 - 2
.quad 0
Expand Down
11 changes: 10 additions & 1 deletion boot/multiboot2/init.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,9 +20,10 @@
#include <multiboot2/init.h>

#include <kernel/core/kentry.h>
#include <kernel/core/mm_init.h>
#include <kernel/core/mm.h>
#include <kernel/core/gdt.h>
#include <kernel/core/logging.h>
#include <kernel/core/proc_data.h>

#include <drivers/acpi/tables.h>

Expand All @@ -46,6 +47,9 @@
#define VIDEO_XRGB8888_BLUEMASK 0x08
#define VIDEO_XRGB8888_BPP 32

struct proc_data_t bsp_proc_data;
static struct proc_data_t* bsp_proc_data_ptr;

struct mb2_tag_memmap_entry_t {
uint64_t base;
uint64_t length;
Expand Down Expand Up @@ -134,11 +138,16 @@ static void next_segment(uint64_t* handle, struct mem_segment_t* seg) {


void multiboot2_init(struct mb2_info_t* info) {
bsp_proc_data_ptr = &bsp_proc_data;
proc_data_ptr = &bsp_proc_data_ptr;
proc_data_set_id(0);
proc_data_get()->arb_id = 0;
logging_init();

#ifdef SERIAL
serial_init_com1();
serial_init_com2();
serial_print_init();

serial_print_com1("COM1\r\n");
serial_print_com2("COM2\r\n");
Expand Down
50 changes: 21 additions & 29 deletions drivers/acpica_osl/osl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -35,15 +35,15 @@
#include <kernel/core/kentry.h>
#include <kernel/core/time.h>
#include <kernel/core/clock_src.h>
#include <kernel/core/lock.h>
#include <kernel/core/process.h>

ACPI_STATUS AcpiOsInitialize(void) {
return AE_OK;
}

ACPI_THREAD_ID AcpiOsGetThreadId(void) {
//TODO: implement
//logging_log_warning("Call to unfinished AcpiOsGetThreadId");
return 1;
return process_get_pid();
}

void ACPI_INTERNAL_XFACE AcpiOsPrintf(const char* fmt, ...) {
Expand All @@ -62,9 +62,7 @@ void* AcpiOsAllocate(ACPI_SIZE size) {
}

void AcpiOsFree(void* ptr) {
//TODO: implement
//logging_log_warning("Call to unfinished AcpiOsFree 0x%lx", ptr);
(void)ptr;
kfree(ptr);
}

ACPI_STATUS AcpiOsCreateSemaphore(UINT32 cap, UINT32 init, ACPI_SEMAPHORE* handle) {
Expand Down Expand Up @@ -101,30 +99,26 @@ ACPI_STATUS AcpiOsSignalSemaphore(ACPI_SEMAPHORE handle, UINT32 units) {
}

ACPI_STATUS AcpiOsCreateLock(ACPI_SPINLOCK* handle) {
//TODO: implement
*handle = (void*)1;
//logging_log_warning("Call to unfinished AcpiOsCreateLock");
return AE_OK;
*handle = kmalloc(sizeof(uint8_t));
if (*handle) {
lock_init(*handle);
return AE_OK;
}
return AE_ERROR;
}

void AcpiOsDeleteLock(ACPI_SPINLOCK handle) {
//TODO: implement
//logging_log_warning("Call to unfinished AcpiOsCreateLock");
(void)handle;
kfree(handle);
}

ACPI_CPU_FLAGS AcpiOsAcquireLock(ACPI_SPINLOCK handle) {
//TODO: implement
//logging_log_warning("Call to unfinished AcpiOsAcquireLock");
(void)handle;
lock_acquire(handle);
return 0;
}

void AcpiOsReleaseLock(ACPI_SPINLOCK handle, ACPI_CPU_FLAGS flg) {
//TODO: implement
//logging_log_warning("Call to unfinished AcpiOsReleaseLock");
(void)handle;
(void)flg;
lock_release(handle);
}

ACPI_STATUS AcpiOsReadMemory(ACPI_PHYSICAL_ADDRESS paddr, UINT64* val, UINT32 width) {
Expand Down Expand Up @@ -238,15 +232,10 @@ void* AcpiOsMapMemory(ACPI_PHYSICAL_ADDRESS paddr, ACPI_SIZE len) {
const uint64_t page_base = paddr & PAGE_BASE_MASK;
const uint64_t adj = paddr - page_base;
len += adj;
uint64_t order = mm_lowest_order(len);
if (order == (uint64_t)-1) {
logging_log_error("Could not allocate contigious virtual block of 0x%lx", (uint64_t)len);
panic(PANIC_NO_MEM);
}
const uint64_t vaddr = mm_alloc_dv((enum mm_order_t)order);
const uint64_t vaddr = mm_alloc_v(len);
if (!vaddr) {
logging_log_error("Could not allocate contigious virtual block of 0x%lx", (uint64_t)len);
panic(PANIC_NO_MEM);
return 0;
}

for (uint64_t i = 0; i < len; i += PAGE_SIZE_4K) {
Expand All @@ -257,9 +246,12 @@ void* AcpiOsMapMemory(ACPI_PHYSICAL_ADDRESS paddr, ACPI_SIZE len) {
}

void AcpiOsUnmapMemory(void* vaddr, ACPI_SIZE len) {
//logging_log_warning("Call to unfinished AcpiOsUnmapMemory");
(void)vaddr;
(void)len;
const uint64_t page_base = (uint64_t)vaddr & PAGE_BASE_MASK;
const uint64_t adj = (uint64_t)vaddr - page_base;
len += adj;
for (uint64_t i = 0; i < len; i += PAGE_SIZE_4K) {
paging_unmap(page_base + i, PAGE_4K);
}
}

ACPI_STATUS AcpiOsTableOverride(ACPI_TABLE_HEADER* existing, ACPI_TABLE_HEADER** override) {
Expand Down
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