Interrupt analysis - removed many useless cli/sti

14 files changed, 90 insertions, 87 deletions

diff --git a/src/kernel/boot.asm b/src/kernel/boot.asm
index 22d66ad..8e6761c 100644
--- a/src/kernel/boot.asm
+++ b/src/kernel/boot.asm
@@ -43,5 +43,5 @@ section .text
 		push eax
 		cli
 		call kernel_main
-		; cli
+		cli
 		jmp $
\ No newline at end of file
diff --git a/src/kernel/fs/elf.c b/src/kernel/fs/elf.c
index be1bc95..c89fd2e 100644
--- a/src/kernel/fs/elf.c
+++ b/src/kernel/fs/elf.c
@@ -25,7 +25,6 @@ int is_elf(struct elf_header *header)
 
 struct process *elf_load(char *path)
 {
-	cli();
 	u8 *file = read_file(path);
 	if (!file) {
 		warn("File or directory not found: %s", path);
@@ -73,6 +72,5 @@ struct process *elf_load(char *path)
 	}
 
 	paging_switch_directory(paging_root_directory);
-	sti();
 	return proc;
 }
\ No newline at end of file
diff --git a/src/kernel/interact.asm b/src/kernel/interact.asm
index 59fbfe7..e7d7e86 100644
--- a/src/kernel/interact.asm
+++ b/src/kernel/interact.asm
@@ -77,10 +77,10 @@ section .text
       pop  fs                                ; load fs from 16bit stack
       pop  es                                ; load es from 16bit stack
       pop  ds                                ; load ds from 16bit stack
-      ; sti                                    ; enable interrupts
+      ;sti                                   ; enable interrupts
       db 0xCD                                ; opcode of INT instruction with immediate byte
    ib: db 0x00
-      cli                                    ; disable interrupts
+      ;cli                                   ; disable interrupts
       xor  sp, sp                            ; zero sp so we can reuse it
       mov  ss, sp                            ; set ss so the stack is valid
       mov  sp, INT32_BASE                    ; set correct stack position so we can copy back
diff --git a/src/kernel/interrupts/irq.asm b/src/kernel/interrupts/irq.asm
index f616944..da7323e 100644
--- a/src/kernel/interrupts/irq.asm
+++ b/src/kernel/interrupts/irq.asm
@@ -1,10 +1,10 @@
 %macro IRQ 2
   global irq%1
   irq%1:
-    cli
-    push byte 0
-    push byte %2
-    jmp irq_common_stub
+	cli
+	push byte 0
+	push byte %2
+	jmp irq_common_stub
 %endmacro
 
 IRQ 0, 32
@@ -26,29 +26,30 @@ IRQ 15, 47
 
 extern irq_handler
 irq_common_stub:
-    pusha
+	pusha
 
-    push ds
-    push es
-    push fs
-    push gs
+	push ds
+	push es
+	push fs
+	push gs
 
-    mov ax, 0x10
-    mov ds, ax
-    mov es, ax
-    mov fs, ax
-    mov gs, ax
-    cld
+	mov ax, 0x10
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	cld
 
-    push esp
-    call irq_handler
-    add esp, 4
+	push esp
+	call irq_handler
+	add esp, 4
 
-    pop gs
-    pop fs
-    pop es
-    pop ds
-    popa
+	pop gs
+	pop fs
+	pop es
+	pop ds
+	popa
 
-    add esp, 8
-    iret
\ No newline at end of file
+	add esp, 8
+	sti
+	iret
\ No newline at end of file
diff --git a/src/kernel/interrupts/isr.asm b/src/kernel/interrupts/isr.asm
index 00d986a..7bfa876 100644
--- a/src/kernel/interrupts/isr.asm
+++ b/src/kernel/interrupts/isr.asm
@@ -1,18 +1,18 @@
 %macro ISR_NOERRCODE 1
-    global isr%1
-    isr%1:
-        cli
-        push byte 0
-        push %1
-        jmp isr_common_stub
+	global isr%1
+	isr%1:
+		cli
+		push byte 0
+		push %1
+		jmp isr_common_stub
 %endmacro
 
 %macro ISR_ERRCODE 1
-    global isr%1
-    isr%1:
-        cli
-        push byte %1
-        jmp isr_common_stub
+	global isr%1
+	isr%1:
+		cli
+		push byte %1
+		jmp isr_common_stub
 %endmacro
 
 ISR_NOERRCODE 0
@@ -51,11 +51,11 @@ ISR_NOERRCODE 128
 
 extern fault_handler
 isr_common_stub:
-    pusha
+	pusha
 
-    push ds
-    push es
-    push fs
+	push ds
+	push es
+	push fs
 	push gs
 
 	mov ax, 0x10
@@ -70,10 +70,11 @@ isr_common_stub:
 	add esp, 4
 
 	pop gs
-    pop fs
-    pop es
+	pop fs
+	pop es
 	pop ds
-    popa
+	popa
 
-    add esp, 8
+	add esp, 8
+	sti
 	iret
\ No newline at end of file
diff --git a/src/kernel/interrupts/isr.c b/src/kernel/interrupts/isr.c
index 9222406..3bfc2b8 100644
--- a/src/kernel/interrupts/isr.c
+++ b/src/kernel/interrupts/isr.c
@@ -103,14 +103,12 @@ const char *exception_messages[32] = { "Division By Zero",
 				       "Reserved",
 				       "Reserved" };
 
-// Master exception/interrupt/fault handler - halt via panic
+// Master exception/interrupt/fault handler - called by asm
 void fault_handler(struct regs *r)
 {
-	cli();
 	irq_handler_t handler = isr_routines[r->int_no];
 	if (handler) {
 		handler(r);
-		sti();
 	} else {
 		u32 faulting_address;
 		asm("mov %%cr2, %0" : "=r"(faulting_address));
diff --git a/src/kernel/io/io.c b/src/kernel/io/io.c
index ad63c88..2d9d009 100644
--- a/src/kernel/io/io.c
+++ b/src/kernel/io/io.c
@@ -22,6 +22,20 @@ u32 inl(u16 port)
 	return value;
 }
 
+u32 cpu_flags()
+{
+	u32 flags;
+	asm volatile("pushf\n"
+		     "pop %0\n"
+		     : "=rm"(flags)::"memory");
+	return flags;
+}
+
+int interrupts_enabled()
+{
+	return (cpu_flags() & 0x200) == 0x200;
+}
+
 void cli()
 {
 	asm volatile("cli");
diff --git a/src/kernel/io/io.h b/src/kernel/io/io.h
index 8b3dd2f..ba5e7c1 100644
--- a/src/kernel/io/io.h
+++ b/src/kernel/io/io.h
@@ -24,6 +24,7 @@ u16 inw(u16 port);
  */
 u32 inl(u16 port);
 
+int interrupts_enabled();
 void cli();
 void sti();
 void hlt();
diff --git a/src/kernel/kernel.c b/src/kernel/kernel.c
index 6010716..d28987b 100644
--- a/src/kernel/kernel.c
+++ b/src/kernel/kernel.c
@@ -49,13 +49,11 @@ void kernel_main(u32 magic, u32 multiboot_address, u32 esp)
 	paging_install();
 
 	// Install drivers
-	cli();
 	timer_install();
 	mouse_install();
 	keyboard_install();
 	pci_remap();
 	network_install();
-	sti();
 
 	memory_print();
 	rtc_print();
@@ -67,6 +65,7 @@ void kernel_main(u32 magic, u32 multiboot_address, u32 esp)
 	set_optimal_resolution();
 	log("Content of /etc/test: %s", read_file("/etc/test"));
 
+	sti(); // Disabled until now
 	syscalls_install();
 	kexec("/bin/init");
 
diff --git a/src/kernel/syscall/actions/sys_wait.c b/src/kernel/syscall/actions/sys_wait.c
index c716221..a252d1f 100644
--- a/src/kernel/syscall/actions/sys_wait.c
+++ b/src/kernel/syscall/actions/sys_wait.c
@@ -4,7 +4,6 @@
 
 u32 sys_wait(u32 pid, u32 *status, u32 options)
 {
-	sti();
 	u32 ret;
 
 	if (pid < 0) { // Wait for any process in gid to die
diff --git a/src/kernel/syscall/syscall.c b/src/kernel/syscall/syscall.c
index d46d3fa..c98707f 100644
--- a/src/kernel/syscall/syscall.c
+++ b/src/kernel/syscall/syscall.c
@@ -24,8 +24,6 @@ u32 (*syscalls[])() = { [SYS_HALT] = (u32(*)())halt_loop, // DEBUG!
 
 void syscall_handler(struct regs *r)
 {
-	cli();
-
 	if (r->eax >= sizeof(syscalls) / sizeof(*syscalls))
 		return;
 
@@ -37,7 +35,6 @@ void syscall_handler(struct regs *r)
 	    r->edx, r->esi, r->edi);
 
 	r->eax = location(r->ebx, r->ecx, r->edx, r->esi, r->edi);
-	sti();
 }
 
 void syscalls_install()
diff --git a/src/kernel/tasks/process.c b/src/kernel/tasks/process.c
index efd55c3..0ba3fbe 100644
--- a/src/kernel/tasks/process.c
+++ b/src/kernel/tasks/process.c
@@ -21,7 +21,6 @@ extern u32 stack_hold;
 
 void scheduler(struct regs *regs)
 {
-	cli();
 	memcpy(&current_proc->registers, regs, sizeof(struct regs));
 
 	timer_handler(regs);
@@ -45,12 +44,10 @@ void scheduler(struct regs *regs)
 
 	memcpy(regs, &current_proc->registers, sizeof(struct regs));
 	paging_switch_directory(current_proc->cr3);
-	sti();
 }
 
 void process_init(struct process *proc)
 {
-	cli();
 	log("Initializing process %d", pid);
 	root = proc;
 	root->pid = pid++;
@@ -60,13 +57,11 @@ void process_init(struct process *proc)
 
 	current_proc = root;
 	irq_install_handler(0, scheduler);
-	sti();
 	userspace_enter(proc);
 }
 
 u32 process_spawn(struct process *process)
 {
-	cli();
 	debug("Spawning process %d", process->pid);
 	process->next = root->next;
 	root->next = process;
@@ -76,13 +71,11 @@ u32 process_spawn(struct process *process)
 
 	//process_suspend(current_proc->pid);
 
-	sti();
 	return process->pid;
 }
 
 u32 process_wait_gid(u32 gid, u32 *status)
 {
-	cli(); // ?
 	struct process *i = root;
 
 	while (i != NULL) {
@@ -95,13 +88,11 @@ u32 process_wait_gid(u32 gid, u32 *status)
 		i = i->next;
 	}
 
-	sti();
 	return WAIT_OKAY;
 }
 
 u32 process_wait_pid(u32 pid, u32 *status)
 {
-	cli(); // ?
 	struct process *i = current_proc->next;
 
 	while (i != NULL) {
@@ -116,13 +107,11 @@ u32 process_wait_pid(u32 pid, u32 *status)
 		i = i->next;
 	}
 
-	sti();
 	return WAIT_ERROR;
 }
 
 void process_suspend(u32 pid)
 {
-	cli();
 	debug("Suspending process %d", pid);
 	struct process *proc = process_from_pid(pid);
 
@@ -132,12 +121,10 @@ void process_suspend(u32 pid)
 	}
 
 	proc->state = PROC_ASLEEP;
-	sti();
 }
 
 void process_wake(u32 pid)
 {
-	cli();
 	debug("Waking process %d", pid);
 	struct process *proc = process_from_pid(pid);
 
@@ -145,12 +132,10 @@ void process_wake(u32 pid)
 		return;
 
 	proc->state = PROC_RUNNING;
-	sti();
 }
 
 u32 process_child(struct process *child, u32 pid)
 {
-	cli();
 	debug("Spawning child process %d", pid);
 	process_suspend(pid);
 
@@ -161,13 +146,11 @@ u32 process_child(struct process *child, u32 pid)
 
 	child->parent = parent;
 
-	sti();
 	return process_spawn(child);
 }
 
 struct process *process_from_pid(u32 pid)
 {
-	cli();
 	struct process *proc = root;
 
 	while (proc != NULL) {
@@ -177,13 +160,11 @@ struct process *process_from_pid(u32 pid)
 		proc = proc->next;
 	}
 
-	sti();
 	return PID_NOT_FOUND;
 }
 
 struct process *process_make_new()
 {
-	cli();
 	debug("Making new process %d", pid);
 	struct process *proc = (struct process *)kmalloc_a(sizeof(struct process));
 	proc->registers.cs = 0x1B;
@@ -197,26 +178,22 @@ struct process *process_make_new()
 		proc->cr3->tables[i] = paging_root_directory->tables[i];
 
 	proc->pid = pid++;
-	sti();
 	return proc;
 }
 
 u32 kexec(char *path)
 {
-	cli();
 	debug("Starting kernel process %s", path);
 	struct process *proc = elf_load(path);
 	if (proc == NULL)
 		return -1;
 
 	process_init(proc);
-	sti();
 	return 0;
 }
 
 u32 uexec(char *path)
 {
-	cli();
 	debug("Starting user process %s", path);
 	process_suspend(current_proc->pid);
 
@@ -228,13 +205,11 @@ u32 uexec(char *path)
 	proc->gid = current_proc->pid;
 	process_spawn(proc);
 	log("Spawned");
-	sti();
 	return 0;
 }
 
 u32 uspawn(char *path)
 {
-	cli();
 	debug("Spawning user process %s", path);
 
 	struct process *proc = elf_load(path);
@@ -245,6 +220,5 @@ u32 uspawn(char *path)
 	proc->gid = current_proc->pid;
 	process_spawn(proc);
 	log("Spawned");
-	sti();
 	return 0;
 }
\ No newline at end of file
diff --git a/src/kernel/tasks/userspace.c b/src/kernel/tasks/userspace.c
index aedec2b..c3fc7e2 100644
--- a/src/kernel/tasks/userspace.c
+++ b/src/kernel/tasks/userspace.c
@@ -21,7 +21,6 @@ u32 spawn_child(struct process *child)
 
 void userspace_enter(struct process *proc)
 {
-	cli();
 	proc_bottom = proc;
 	proc->next = NULL;
 	hl_eip = proc->registers.eip;
@@ -31,7 +30,7 @@ void userspace_enter(struct process *proc)
 	current_proc = proc;
 
 	debug("Jumping to userspace!");
-	sti(); // TODO: Prevent race conditions in userspace jumping
+	//sti(); // TODO: Prevent race conditions in userspace jumping
 	jump_userspace();
 }
 
diff --git a/src/userspace/programs/init.c b/src/userspace/programs/init.c
index 64da122..306aee6 100644
--- a/src/userspace/programs/init.c
+++ b/src/userspace/programs/init.c
@@ -5,6 +5,20 @@
 #include <syscall.h>
 #include <unistd.h>
 
+u32 cpu_flags()
+{
+	u32 flags;
+	asm volatile("pushf\n"
+		     "pop %0\n"
+		     : "=rm"(flags)::"memory");
+	return flags;
+}
+
+int interrupts_enabled()
+{
+	return (cpu_flags() & 0x200) == 0x200;
+}
+
 void main()
 {
 	if (get_pid() != 1) {
@@ -12,6 +26,11 @@ void main()
 		exit(1);
 	}
 
+	if (interrupts_enabled())
+		printf("INTs enabled :)\n");
+	else
+		printf("INTs disabled :(\n");
+
 	// TODO: Fix page fault when mallocing
 	printf("Initializing userspace...\n");
 
@@ -19,7 +38,10 @@ void main()
 	// TODO: Fix occasional race conditions with cli/sti
 	// TODO: Fix scheduler turning off at some point
 	spawn("/bin/sh");
-	printf("AWESOME");
+	if (interrupts_enabled())
+		printf("INTs enabled :)\n");
+	else
+		printf("INTs disabled :(\n");
 
 	while (1) {
 		//printf("B");