set TS flag at boot timer to detect the first FPU access

- the first FPU access requires an FPU init

hermit/arch/x86/include/asm/processor.h

@@ -722,8 +722,17 @@ static inline void register_task(void)
  */
 inline static int system_calibration(void)
 {
+	size_t cr0;
+
 	apic_init();
 	register_task();
+
+	// set task switched flag for the first FPU access
+	//  => initialize the FPU
+	cr0 = read_cr0();
+	cr0 |= CR0_TS;
+	write_cr0(cr0);
+
 	irq_enable();
 	detect_cpu_frequency();
 	apic_calibration();

hermit/arch/x86/kernel/apic.c

@@ -669,6 +669,12 @@ int smp_start(void)
 	//kprintf("CR0 of core %u: 0x%x\n", atomic_int32_read(&current_boot_id), read_cr0());
 	online[atomic_int32_read(&current_boot_id)] = 1;
 
+	// set task switched flag for the first FPU access
+	// => initialize the FPU
+	size_t cr0 = read_cr0();
+	cr0 |= CR0_TS;
+	write_cr0(cr0);
+
 	set_idle_task();
 
 	irq_enable();

hermit/arch/x86/kernel/tasks.c

@@ -97,14 +97,6 @@ static int thread_entry(void* arg, size_t ep)
 	if (init_tls())
 		return -ENOMEM;
 
-#ifndef SAVE_FPU
-	// set task switched flag for the first FPU access
-	// => initialize the FPU
-	size_t cr0 = read_cr0();
-	cr0 |= CR0_TS;
-	write_cr0(cr0);
-#endif
-
 	//vma_dump();
 
 	// set first argument