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wip on fork

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minimal example works
This commit is contained in:
Eggert Jung
2026-02-25 11:32:22 +01:00
parent 22ab2fb2a5
commit 8b271e2470
8 changed files with 64 additions and 18 deletions
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6
kernel/main.cc
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@@ -100,9 +100,9 @@ extern "C" int main() {
}
Thread* thread_ptr = new Thread(false, (void*)0x4000000, (void*)0x4001000, 2);
g.vault().scheduler.ready(thread_ptr);
g.vault().thread_list[thread_ptr->id] = thread_ptr;
//Thread* thread_ptr = new Thread(false, (void*)0x4000000, (void*)0x4001000, 2);
//g.vault().scheduler.ready(thread_ptr);
//g.vault().thread_list[thread_ptr->id] = thread_ptr;
//for(void* p=Multiboot::getModule(0)->getStartAddress(); p<Multiboot::getModule(0)->getEndAddress(); p=(void*)((uintptr_t)p+4096)){
// DBG << "module at: " << hex << p << endl;

2
kernel/memory/pagetable.cc
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@@ -231,6 +231,8 @@ void copy_pagetable(four_lvl_paging_t* parent_table, four_lvl_paging_t* child_ta
((uintptr_t)i3<<30) |
((uintptr_t)i2<<21) |
((uintptr_t)i1<<12) ;
if(vaddr < 0x4000000)
continue;
if(!isMapped(vaddr, child_table)){
//only copy if not part of basic pagetable
assert( (i3>0) || (i2>=32)); //assert user memory

29
kernel/syscall/skeleton.cc
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@@ -9,6 +9,7 @@
#include "../thread/scheduler.h"
#include "../memory/pageframealloc.h"
#include "../memory/pagetable.h"
#include "../arch/idt.h"
void *operator new(size_t, void *);
//#include "../user/app1/appl.h"
@@ -175,8 +176,6 @@ namespace Syscall {
bool copy_from_phys(Vault& vault, uintptr_t phys_ptr, void* virt_ptr, size_t size) {
Thread* current_thread = vault.scheduler.active();
size_t offset = Page::offset(phys_ptr);
size_t total_size = size + offset;
four_lvl_paging_t* search_table = vault.scheduler.active()->paging_tree;
@@ -185,10 +184,10 @@ bool copy_from_phys(Vault& vault, uintptr_t phys_ptr, void* virt_ptr, size_t siz
if (virt_addr == nullptr) {
return false;
}
for(uint8_t i =0; i<size/4096 +1; i++){
setMapping((uintptr_t)virt_addr, (void*)phys_ptr, vault.scheduler.active()->paging_tree);
}
for(uint8_t i =0; i<size/4096 +1; i++){
setMapping((uintptr_t)virt_addr, (void*)phys_ptr, vault.scheduler.active()->paging_tree);
}
memcpy(virt_ptr, (void*)((uintptr_t)(virt_addr)+ (uintptr_t)offset), size);
setMapping((uintptr_t)(virt_addr), 0, search_table);
@@ -280,9 +279,25 @@ bool reply(Vault& v, const void* buffer, size_t size) {
return true;
}
void copy_stack(Thread* parent, Thread* child){
uintptr_t dest_frame = isMapped((uintptr_t)child->StackPointer.user, child->paging_tree);
void* dest_vaddr = getFreeVirtSpace(parent->paging_tree, 1);
setMapping((uintptr_t)dest_vaddr, (void*)dest_frame, parent->paging_tree);
memcpy(dest_vaddr, (void*)0x6000000/*((uintptr_t)parent->StackPointer.user & ~0xFFF)*/, 4096);
setMapping((uintptr_t)dest_vaddr, 0, parent->paging_tree);
}
int fork(Vault &vault, InterruptContext *user_context) {
Thread* parent = vault.scheduler.active();
//Thread* child = new Thread(false,
Thread* child = new Thread(false, (void*)user_context->ip, parent->code_paddr, parent->code_pagenum);
copy_pagetable(parent->paging_tree, child->paging_tree);
copy_stack(parent, child);
child->StackPointer.user = (void*)user_context->sp;
vault.scheduler.ready(child);
return 0;
}

14
kernel/syscall/stub.asm
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@@ -6,7 +6,21 @@
align 8
sys_call:
; BSB2 1 - Syscall stub
push rbx
push rbp
push r11
push r12
push r13
push r14
push r15
int 0x80
pop r15
pop r14
pop r13
pop r12
pop r11
pop rbp
pop rbx
ret

7
kernel/thread/thread.cc
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@@ -4,6 +4,7 @@
#include "../arch/core_ring.h"
#include "../memory/pageframealloc.h"
#include "../memory/pagetable.h"
#include "../memory/page.h"
#include "../debug/kernelpanic.h"
#include "../interrupt/guard.h"
#include "debug/output.h"
@@ -49,11 +50,11 @@ void Thread::map_app(void* code_paddr, uint16_t code_page_num, void* stack_vaddr
}
}
Thread::Thread (bool kernel, void* start_addr, void * codeframe, int code_frame_num): queue_link(nullptr), isKernel(kernel), start(start_addr), id(idCounter++), kill_flag(false){
Thread::Thread (bool kernel, void* start_addr, void * codeframe, int code_frame_num): queue_link(nullptr), isKernel(kernel), start(start_addr), code_paddr(codeframe), code_pagenum(code_frame_num), id(idCounter++), kill_flag(false){
StackPointer.isr = reinterpret_cast<void *>((uintptr_t)PageFrameAllocator::alloc(true)+STACK_SIZE);// mapped due to identity mapping
StackPointer.user = (void*)(0x61FF000+STACK_SIZE);
StackPointer.user = (void*)(0x6000000+STACK_SIZE);
map_app(codeframe, code_frame_num, StackPointer.user, 1);
map_app(codeframe, code_frame_num, (void*)((uintptr_t)StackPointer.user-STACK_SIZE), 1);
prepareContext(StackPointer.isr, context, kickoff, reinterpret_cast<uintptr_t>(this), 0, 0);
}

7
kernel/thread/thread.h
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@@ -57,7 +57,6 @@ class Thread {
/*! \brief Context of the thread, used for saving and restoring the register
* values when context switching.
*/
Context context;
/*! \brief The thread's entry point.
*
@@ -87,9 +86,11 @@ class Thread {
} StackPointer;
void* operator new ( size_t count )noexcept;
Context context;
four_lvl_paging_t* paging_tree;
pagetable_t* appcode_table;
pagetable_t* appstack_table;
void* code_paddr;
int code_pagenum;
Semaphore ipc_sem;
Queue<IpcStruct> ipc_queue;

3
notes
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@@ -31,3 +31,6 @@
| |
| |
schedule(2) kickoff
p/x ((pagetable_t*)(((pagetable_t*)(((pagetable_t*)(child.paging_tree.l4.entries[0].address<<12)).entries[0].address<<12)).entries[0].address<<12)).entries[0]

14
user/app1/appl.cc
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@@ -45,13 +45,23 @@ extern "C" void main() {
//sys_test(1,2,3,4,5);
fork();
unsigned id = sys_getpid();
char text[] = "appX";
text[3] = 0x30+id;
write(1, text, sizeof(text), 0, (int)id);
uint8_t cnt = 0;
while(1){
cnt = (cnt+1)%100;
char msg[12];
char* num = itoa(cnt, msg);
write(1, num, strlen(num), 10, (int)id);
sleep(100);
}
for (uint8_t i = 1;; ++i) {
//counter to see app running
cnt=(cnt+1)%100;