Add kernel logging task

- Enable creating kernel tasks
- Create kernel task that disables immediate-mode logging and prints
  logs to the console forever

src/kernel/cpu.cpp

@@ -3,6 +3,8 @@
 #include "cpu.h"
 #include "log.h"
 
+cpu_data bsp_cpu_data;
+
 inline static void
 __cpuid(
 	uint32_t leaf,

src/kernel/cpu.h

@@ -10,6 +10,14 @@ struct cpu_state
 	uint64_t rip, cs, rflags, user_rsp, ss;
 };
 
+struct cpu_data
+{
+	uintptr_t rsp0;
+	uintptr_t rsp3;
+};
+
+extern cpu_data bsp_cpu_data;
+
 class cpu_id
 {
 public:

src/kernel/debug.cpp

@@ -4,10 +4,6 @@
 #include "gdt.h"
 #include "page_manager.h"
 
-#define print_regL(name, value) cons->printf("       %s: %016lx", name, (value));
-#define print_regM(name, value) cons->printf("    %s: %016lx", name, (value));
-#define print_regR(name, value) cons->printf("    %s: %016lx\n", name, (value));
-
 size_t __counter_syscall_enter = 0;
 size_t __counter_syscall_sysret = 0;
 
@@ -36,7 +32,7 @@ print_regs(const cpu_state &regs)
 	cons->puts("\n\n");
 	print_regL("rbp", regs.rbp);
 	print_regM("rsp", regs.user_rsp);
-	print_regR("sp0", tss_get_stack(0));
+	print_regR("sp0", bsp_cpu_data.rsp0);
 
 	print_regL("rip", regs.rip);
 	print_regM("cr3", page_manager::get()->get_pml4());

src/kernel/debug.h

@@ -18,5 +18,7 @@ void print_regs(const cpu_state &regs);
 void print_stack(const cpu_state &regs);
 void print_stacktrace(int skip);
 
-#define print_reg(name, value) cons->printf("         %s: %016lx\n", name, (value));
+#define print_regL(name, value) cons->printf("       %s: %016lx", name, (value));
+#define print_regM(name, value) cons->printf("    %s: %016lx", name, (value));
+#define print_regR(name, value) cons->printf("    %s: %016lx\n", name, (value));
 

src/kernel/interrupts.cpp

@@ -111,6 +111,38 @@ isr_handler(uintptr_t return_rsp, cpu_state *regs)
 
 	switch (static_cast<isr>(regs->interrupt & 0xff)) {
 
+	case isr::isrDebug: {
+			cons->set_color(11);
+			cons->puts("\nDebug Exception:\n");
+			cons->set_color();
+
+			uint64_t dr = 0;
+
+			__asm__ __volatile__ ("mov %%dr0, %0" : "=r"(dr));
+			print_regL("dr0", dr);
+
+			__asm__ __volatile__ ("mov %%dr1, %0" : "=r"(dr));
+			print_regM("dr1", dr);
+
+			__asm__ __volatile__ ("mov %%dr2, %0" : "=r"(dr));
+			print_regM("dr2", dr);
+
+			__asm__ __volatile__ ("mov %%dr3, %0" : "=r"(dr));
+			print_regR("dr3", dr);
+
+			__asm__ __volatile__ ("mov %%dr6, %0" : "=r"(dr));
+			print_regL("dr6", dr);
+
+			__asm__ __volatile__ ("mov %%dr7, %0" : "=r"(dr));
+			print_regR("dr7", dr);
+
+			print_regL("rip", regs->rip);
+			print_regM("rsp", regs->user_rsp);
+			print_regM("fla", regs->rflags);
+			_halt();
+		}
+		break;
+
 	case isr::isrGPFault: {
 			cons->set_color(9);
 			cons->puts("\nGeneral Protection Fault:\n");
@@ -145,7 +177,6 @@ isr_handler(uintptr_t return_rsp, cpu_state *regs)
 			print_stacktrace(2);
 			print_stack(*regs);
 			*/
-
 		}
 		_halt();
 		break;
@@ -165,12 +196,9 @@ isr_handler(uintptr_t return_rsp, cpu_state *regs)
 
 			uint64_t cr2 = 0;
 			__asm__ __volatile__ ("mov %%cr2, %0" : "=r"(cr2));
-			print_reg("cr2", cr2);
-
-			print_reg("rsp", regs->user_rsp);
-			print_reg("rip", regs->rip);
-
-			cons->puts("\n");
+			print_regL("cr2", cr2);
+			print_regM("rsp", regs->user_rsp);
+			print_regR("rip", regs->rip);
 			//print_stacktrace(2);
 		}
 		_halt();
@@ -242,7 +270,7 @@ isr_handler(uintptr_t return_rsp, cpu_state *regs)
 				regs->interrupt, regs->errorcode);
 
 		print_regs(*regs);
-		//print_stacktrace(2);
+		print_stacktrace(2);
 		_halt();
 	}
 	*reinterpret_cast<uint32_t *>(0xffffff80fee000b0) = 0;

src/kernel/log.cpp

@@ -28,6 +28,31 @@ output_log(log::area_t area, log::level severity, const char *message)
 	cons->set_color();
 }
 
+void
+logger_task()
+{
+	uint8_t buffer[257];
+	auto *ent = reinterpret_cast<log::logger::entry *>(buffer);
+	auto *cons = console::get();
+
+	g_logger.set_immediate(nullptr);
+	log::info(logs::task, "Starting kernel logger task");
+
+	while (true) {
+		__asm__ ("cli");
+		if(g_logger.get_entry(buffer, sizeof(buffer))) {
+			buffer[ent->bytes] = 0;
+			cons->set_color(level_colors[static_cast<int>(ent->severity)]);
+			cons->printf("%9s %8s: %s\n",
+				g_logger.area_name(ent->area),
+				g_logger.level_name(ent->severity),
+				ent->message);
+			cons->set_color();
+		}
+		__asm__ ("sti");
+	}
+}
+
 void init()
 {
 	new (&g_logger) log::logger(log_buffer, sizeof(log_buffer));

src/kernel/log.h

@@ -11,6 +11,7 @@ namespace logs {
 #undef LOG
 
 void init();
+void logger_task();
 
 } // namespace logs
 

src/kernel/main.cpp

@@ -132,6 +132,8 @@ kernel_main(kernel_args *header)
 	syscall_enable();
 	scheduler *sched = new (&scheduler::get()) scheduler(devices->get_lapic());
 
+	sched->create_kernel_task(-1, logs::logger_task);
+
 	for (auto &f : ird.files()) {
 		if (f.executable())
 			sched->load_process(f.name(), f.data(), f.size());

src/kernel/page_manager.h

@@ -108,6 +108,9 @@ public:
 	/// \returns  A pointer to the system page manager
 	static page_manager * get();
 
+	/// Get a pointer to the kernel's PML4
+	inline page_table * get_kernel_pml4() { return m_kernel_pml4; }
+
 private:
 	/// Copy a physical page
 	/// \arg orig  Physical address of the page to copy

src/kernel/process.h

@@ -7,7 +7,7 @@
 #include "kutil/linked_list.h"
 #include "page_manager.h"
 
-typedef uint32_t pid_t;
+typedef int32_t pid_t;
 
 
 enum class process_flags : uint32_t

src/kernel/push_all.inc

@@ -1,6 +1,14 @@
 %macro push_all 0
 	sub rsp, 0x78
 
+	; ss3      rsp + 0xa8
+	; rsp3     rsp + 0xa0
+	; flags3   rsp + 0x98
+	; cs3      rsp + 0x90
+	; rip3     rsp + 0x88
+	; error    rsp + 0x80
+	; vector   rsp + 0x78
+
 	mov [rsp + 0x70], rax
 	mov [rsp + 0x68], rcx
 	mov [rsp + 0x60], rdx

src/kernel/scheduler.cpp

@@ -27,14 +27,6 @@ extern "C" {
 	void load_process(const void *image_start, size_t bytes, process *proc, cpu_state *state);
 };
 
-struct cpu_data
-{
-	uintptr_t rsp0;
-	uintptr_t rsp3;
-};
-
-static cpu_data bsp_cpu_data;
-
 scheduler::scheduler(lapic *apic) :
 	m_apic(apic),
 	m_next_pid(1)
@@ -118,10 +110,12 @@ load_process(const void *image_start, size_t bytes, process *proc, cpu_state *st
 }
 
 process_node *
-scheduler::create_process()
+scheduler::create_process(pid_t pid)
 {
+	kassert(pid <= 0, "Cannot specify a positive pid in create_process");
+
 	auto *proc = m_process_allocator.pop();
-	proc->pid = m_next_pid++;
+	proc->pid = pid ? pid : m_next_pid++;
 	proc->priority = default_priority;
 	return proc;
 }
@@ -189,6 +183,44 @@ scheduler::load_process(const char *name, const void *data, size_t size)
 	log::debug(logs::task, "     PML4 %016lx", pml4);
 }
 
+void
+scheduler::create_kernel_task(pid_t pid, void (*task)())
+{
+	auto *proc = create_process(pid);
+
+	uint16_t kcs = (1 << 3) | 0; // Kernel CS is GDT entry 1, ring 0
+	uint16_t kss = (2 << 3) | 0; // Kernel SS is GDT entry 2, ring 0
+
+	// Create a one-page kernel stack space
+	void *stack0 = proc->setup_kernel_stack(stack_size, 0);
+
+	// Stack grows down, point to the end, resere space for initial null frame
+	static const size_t null_frame = sizeof(uint64_t);
+	void *sp0 = kutil::offset_pointer(stack0, stack_size - null_frame);
+
+	cpu_state *state = reinterpret_cast<cpu_state *>(sp0) - 1;
+
+	// Highest state in the stack is the process' kernel stack for the loader
+	// to iret to:
+	state->ss = kss;
+	state->cs = kcs;
+	state->rflags = rflags_int;
+	state->rip = reinterpret_cast<uint64_t>(task);
+	state->user_rsp = reinterpret_cast<uint64_t>(state);
+
+	proc->rsp = reinterpret_cast<uintptr_t>(state);
+	proc->pml4 = page_manager::get()->get_kernel_pml4();
+	proc->quanta = process_quanta;
+	proc->flags =
+		process_flags::running |
+		process_flags::ready;
+
+	m_runlists[default_priority].push_back(proc);
+
+	log::debug(logs::task, "Creating kernel task: pid %d  pri %d", proc->pid, proc->priority);
+	log::debug(logs::task, "     RSP0 %016lx", state);
+}
+
 void
 scheduler::start()
 {
@@ -276,7 +308,6 @@ scheduler::schedule(uintptr_t rsp0)
 	tss_set_stack(0, rsp0 + sizeof(cpu_state));
 	bsp_cpu_data.rsp0 = rsp0;
 
-
 	// Swap page tables
 	page_table *pml4 = m_current->pml4;
 	page_manager::set_pml4(pml4);

src/kernel/scheduler.h

@@ -21,10 +21,10 @@ public:
 	static const uint8_t default_priority = num_priorities / 2;
 
 	/// How long the timer quantum is
-	static const uint64_t quantum_micros = 100000;
+	static const uint64_t quantum_micros = 1000;
 
 	/// How many quantums a process gets before being rescheduled
-	static const uint16_t process_quanta = 10;
+	static const uint16_t process_quanta = 100;
 
 	/// Constructor.
 	/// \arg apic  Pointer to the local APIC object
@@ -36,6 +36,11 @@ public:
 	/// \arg size  Size of the program image, in bytes
 	void load_process(const char *name, const void *data, size_t size);
 
+	/// Create a new kernel task
+	/// \arg pid   Pid to use for this task, must be negative
+	/// \arg proc  Function to run as a kernel task
+	void create_kernel_task(pid_t pid, void (*task)());
+
 	/// Start the scheduler working. This may involve starting
 	/// timer interrupts or other preemption methods.
 	void start();
@@ -65,8 +70,9 @@ private:
 
 	/// Create a new process object. This process will have its pid
 	/// set but nothing else.
+	/// \arg pid  The pid to give the process (0 for automatic)
 	/// \returns  The new process object
-	process_node * create_process();
+	process_node * create_process(pid_t pid = 0);
 
 	/// Handle a timer tick
 	/// \arg rsp0  The stack pointer of the current interrupt handler