Allocate kernel user stacks in kernel memory space

kernel/include/process.hpp

@@ -44,14 +44,11 @@ struct process_t {
 
 constexpr const size_t program_base = 0x8000000000;
 
-constexpr const auto user_stack_start = program_base + 0x700000;
-constexpr const auto kernel_stack_start = program_base + 0x800000;
-
 constexpr const auto user_stack_size = 2 * paging::PAGE_SIZE;
 constexpr const auto kernel_stack_size = 2 * paging::PAGE_SIZE;
 
+constexpr const auto user_stack_start = program_base + 0x700000;
 constexpr const auto user_rsp = user_stack_start + (user_stack_size - 8);
-constexpr const auto kernel_rsp = kernel_stack_start + (user_stack_size - 8);
 
 } //end of namespace scheduler
 

kernel/src/scheduler.cpp

@@ -58,7 +58,6 @@ void switch_to_process(size_t index){
 
     k_printf("Switched to %u\n", index);
 
-    //TODO Move that to scheduler
     auto& process = processes[current_index];
 
     gdt::tss.rsp0_low = process.kernel_rsp & 0xFFFFFFFF;
@@ -71,11 +70,10 @@ void switch_to_process(size_t index){
 
     asm volatile("mov cr3, %0" : : "r" (process.physical_cr3) : "memory");
 
-    //TODO Check if user_rsp is correctly passed
     asm volatile("xor rax, rax; mov ax, %0; push rax; mov rax, %1; push rax; pushfq; xor rax, rax; mov ax, %2; push rax; mov rax, %3; push rax; iretq"
         :  //No outputs
         : "r" (process.data_selector), "r" (process.user_rsp), "r" (process.code_selector), "r" (process.rip)
-        : "rax");
+        : "rax", "memory");
 }
 
 size_t select_next_process(){

kernel/src/shell.cpp

@@ -809,11 +809,9 @@ bool create_paging(char* buffer, scheduler::process_t& process){
 
     //2.1 Allocate user stack
     allocate_user_memory(process, scheduler::user_stack_start, scheduler::user_stack_size, process.physical_user_stack);
+    process.user_rsp = scheduler::user_rsp;
 
-    //2.2 Allocate kernel stack
+    //2.2 Allocate all user segments
-    allocate_user_memory(process, scheduler::kernel_stack_start, scheduler::kernel_stack_size, process.physical_kernel_stack);
-
-    //2.3 Allocate all user segments
 
     auto header = reinterpret_cast<elf::elf_header*>(buffer);
     auto program_header_table = reinterpret_cast<elf::program_header*>(buffer + header->e_phoff);
@@ -849,6 +847,17 @@ bool create_paging(char* buffer, scheduler::process_t& process){
         }
     }
 
+    //2.3 Allocate kernel stack
+    auto virtual_kernel_stack = virtual_allocator::allocate(scheduler::kernel_stack_size / paging::PAGE_SIZE);
+    auto physical_kernel_stack = physical_allocator::allocate(scheduler::kernel_stack_size / paging::PAGE_SIZE);
+
+    if(!paging::map_pages(virtual_kernel_stack, physical_kernel_stack, scheduler::kernel_stack_size / paging::PAGE_SIZE)){
+        return false;
+    }
+
+    process.physical_kernel_stack = physical_kernel_stack;
+    process.kernel_rsp = virtual_kernel_stack + (scheduler::user_stack_size - 8);
+
     //3. Clear stacks
     clear_physical_memory(process.physical_user_stack, scheduler::user_stack_size / paging::PAGE_SIZE);
     clear_physical_memory(process.physical_kernel_stack, scheduler::kernel_stack_size / paging::PAGE_SIZE);
@@ -887,9 +896,6 @@ void exec_command(const std::vector<std::string>& params){
         return;
     }
 
-    process.kernel_rsp = scheduler::kernel_rsp;
-    process.user_rsp = scheduler::user_rsp;
-
     process.rip = header->e_entry;
 
     process.code_selector = gdt::USER_CODE_SELECTOR + 3;

kernel/src/system_calls.cpp

@@ -7,6 +7,7 @@
 
 #include "system_calls.hpp"
 #include "console.hpp"
+#include "scheduler.hpp"
 
 namespace {
 
@@ -41,7 +42,7 @@ void system_call_entry(const interrupt::syscall_regs& regs){
             break;
 
         case 0x666:
-            //TODO Indicate to the scheduler that the process is over
+            scheduler::kill_current_process();
             break;
 
         default: