kernel: fix remaining _cpu() races

kernel-src/arch/x86-64/hpet.c

@@ -116,7 +116,7 @@ time_t arch_hpet_init() {
 		if (capabilities & HPET_CAP_LEGACYCAPABLE) {
 			type = TYPE_LEGACY;
 
-			arch_ioapic_setirq(0, isr->id & 0xff, _cpu()->id, false);
+			arch_ioapic_setirq(0, isr->id & 0xff, current_cpu_id(), false);
 
 			selectedtimer = 0;
 			timerconfig = read64(HPET_TIMER_CONFIG(selectedtimer));

kernel-src/arch/x86-64/ps2kbd.c

@@ -154,7 +154,7 @@ static void kbdisr(isr_t *isr, context_t *ctx) {
 void ps2kbd_init() {
 	isr_t *isr = interrupt_allocate(kbdisr, arch_apic_eoi, IPL_KEYBOARD);
 	__assert(isr);
-	arch_ioapic_setirq(KEYBOARDIRQ, isr->id & 0xff, _cpu()->id, false);
+	arch_ioapic_setirq(KEYBOARDIRQ, isr->id & 0xff, current_cpu_id(), false);
 	kb = keyboard_new();
 	__assert(kb);
 	printf("ps2kbd: irq enabled with vector %u\n", isr->id & 0xff);

kernel-src/arch/x86-64/ps2mouse.c

@@ -111,7 +111,7 @@ void ps2mouse_init() {
 
 	isr_t *isr = interrupt_allocate(mouseisr, arch_apic_eoi, IPL_MOUSE);
 	__assert(isr);
-	arch_ioapic_setirq(PS2_MOUSEIRQ, isr->id & 0xff, _cpu()->id, false);
+	arch_ioapic_setirq(PS2_MOUSEIRQ, isr->id & 0xff, current_cpu_id(), false);
 	mouse = mouse_new();
 	__assert(mouse);
 	printf("ps2mouse: irq enabled with vector %u\n", isr->id & 0xff);

kernel-src/include/x86-64/arch/cpu.h

@@ -19,9 +19,9 @@ typedef struct cpu_t {
 	thread_t *thread;
 	struct cpu_t *self;
 	vmmcontext_t *vmmctx;
+	long id;
 	uint64_t gdt[7];
 	ist_t ist;
-	long id;
 	isr_t isr[MAX_ISR_COUNT];
 	int acpiid;
 	timer_t *timer;
@@ -78,6 +78,12 @@ static inline void set_current_vmm_context(vmmcontext_t *context) {
 	asm volatile ("mov %%rax, %%gs:16" : : "a"(context) : "memory");
 }
 
+static inline long current_cpu_id(void) {
+	long id;
+	asm volatile ("mov %%gs:24, %%rax" : "=a"(id) : : "memory");
+	return id;
+}
+
 static inline void cpu_set(cpu_t *ptr) {
 	ptr->self = ptr;
 	wrmsr(MSR_GSBASE, (uint64_t)ptr);

kernel-src/include/x86-64/arch/pci.h

@@ -72,7 +72,7 @@ static void mcfg_write32(int bus, int device, int function, uint32_t offset, uin
 
 static uint64_t msiformatmessage(uint32_t *data, int vector, int edgetrigger, int deassert) {
 	*data = (edgetrigger ? 0 : (1 << 15)) | (deassert ? 0 : (1 << 14)) | vector;
-	return 0xfee00000 | (_cpu()->id << 12);
+	return 0xfee00000 | (current_cpu_id() << 12);
 }
 
 // in PCIe, every function has 4096 bytes of config space for it.

kernel-src/io/acpi/glue.c

@@ -294,7 +294,7 @@ uacpi_status uacpi_kernel_install_interrupt_handler(uacpi_u32 irq, uacpi_interru
 	actx->ctx = ctx;
 	isr->priv = actx;
 
-	arch_ioapic_setirq(irq, isr->id & 0xff, _cpu()->id, false);
+	arch_ioapic_setirq(irq, isr->id & 0xff, current_cpu_id(), false);
 
 	*outhandle = isr;
 	return UACPI_STATUS_OK;

kernel-src/lib/panic.c

@@ -4,7 +4,7 @@
 #include <kernel/interrupt.h>
 
 __attribute__((noreturn)) void _panic(char *msg, context_t *ctx) {
-	printf("cpu%lu: Oops.\n", _cpu()->id);
+	printf("cpu%lu: Oops.\n", current_cpu_id());
 
 	if (msg)
 		printf("%s\n", msg);

kernel-src/sys/interrupt.c

@@ -42,11 +42,9 @@ static void runisr(isr_t *isr, context_t *ctx) {
 }
 
 static void dopending(context_t *ctx, void *) {
+	arch_interrupt_disable();
 	bool entrystatus = _cpu()->intstatus;
-	if (entrystatus) {
-		arch_interrupt_disable();
-		_cpu()->intstatus = false;
-	}
+	_cpu()->intstatus = false;
 
 	isr_t *list = NULL;
 	isr_t *iterator = _cpu()->isrqueue;
@@ -135,15 +133,20 @@ void interrupt_raise(isr_t *isr) {
 }
 
 void interrupt_register(int vector, void (*func)(isr_t *self, context_t *ctx), void (*eoi)(isr_t *self), long priority) {
+	bool intstatus = interrupt_set(false);
+
 	isr_t *isr = &_cpu()->isr[vector];
 	isr->func = func;
 	isr->eoi = eoi;
-	isr->id = (uint64_t)_cpu()->id << 32 | vector;
+	isr->id = (uint64_t)current_cpu_id() | vector;
 	isr->priority = priority;
 	isr->pending = false;
+
+	interrupt_set(intstatus);
 }
 
 isr_t *interrupt_allocate(void (*func)(isr_t *self, context_t *ctx), void (*eoi)(isr_t *self), long priority) {
+	bool intstatus = interrupt_set(false);
 	isr_t *isr = NULL;
 
 	for (int i = 0; i < MAX_ISR_COUNT; ++i) {
@@ -154,6 +157,7 @@ isr_t *interrupt_allocate(void (*func)(isr_t *self, context_t *ctx), void (*eoi)
 		}
 	}
 
+	interrupt_set(intstatus);
 	return isr;
 }
 
@@ -183,16 +187,14 @@ long interrupt_raiseipl(long ipl) {
 }
 
 bool interrupt_set(bool status) {
+	arch_interrupt_disable();
 	bool old = _cpu()->intstatus;
 	_cpu()->intstatus = status;
 
-	if (status)
+	if (status) {
 		arch_interrupt_enable();
-	else
-		arch_interrupt_disable();
-
-	if (status)
 		DOPENDING_SAVE();
+	}
 
 	return old;
 }

kernel-src/sys/scheduler.c

@@ -574,10 +574,10 @@ static void yield(context_t *context, void *) {
 }
 
 int sched_yield() {
-	__assert(_cpu()->ipl == IPL_NORMAL);
 	bool sleeping = current_thread()->flags & SCHED_THREAD_FLAGS_SLEEP;
 	bool old = sleeping ? current_thread()->sleepintstatus : interrupt_set(false);
 	arch_context_saveandcall(yield, _cpu()->schedulerstack, NULL);
+	__assert(_cpu()->ipl == IPL_NORMAL);
 	interrupt_set(old);
 	return sleeping ? current_thread()->wakeupreason : 0;
 }