logging: make term and printf smp safe

kernel-src/include/logging.h

@@ -3,9 +3,27 @@
 
 #include <printf.h>
 #include <panic.h>
+#include <mutex.h>
+#include <arch/cpu.h>
 
 void _putchar(char c);
 void logging_sethook(void (*fun)(char));
+void logging_init();
+extern mutex_t printf_mutex;
+
+#ifdef printf
+#undef printf
+#endif
+
+#define printf(...) { \
+	if (_cpu()->thread) {\
+		MUTEX_ACQUIRE(&printf_mutex, false); \
+	} else { \
+		while (MUTEX_TRY(&printf_mutex) == false) CPU_PAUSE(); \
+	} \
+	printf_(__VA_ARGS__); \
+	MUTEX_RELEASE(&printf_mutex); \
+}
 
 #define __assert(x) \
 	if (!(x)){ \

kernel-src/include/semaphore.h

@@ -1,6 +1,7 @@
 #ifndef _SEMAPHORE_H
 #define _SEMAPHORE_H
 
+#include <stddef.h>
 #include <stdbool.h>
 #include <spinlock.h>
 

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

@@ -34,6 +34,7 @@ typedef struct cpu_t {
 } cpu_t;
 
 #define CPU_HALT() asm volatile("hlt")
+#define CPU_PAUSE() asm volatile("pause")
 
 static inline cpu_t *_cpu() {
 	return (cpu_t *)rdmsr(MSR_GSBASE);