cobalt/x86: add ipipe-4.14 eager fpu support

4.14 is always eager, unfortunately we will need a few ifdefs inside the
eager fpu support as well.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
[Jan: converted C++-style comment]
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kernel/cobalt/arch/x86/include/asm/xenomai/wrappers.h

@@ -32,6 +32,10 @@
     LINUX_VERSION_CODE < KERNEL_VERSION(4,5,0)
 #define IPIPE_X86_FPU_EAGER
 #endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,14,0)
+#define IPIPE_X86_FPU_EAGER
+#endif
+
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4,2,0)
 #include <asm/i387.h>

kernel/cobalt/arch/x86/thread.c

@@ -42,6 +42,7 @@ static struct kmem_cache *xstate_cache;
 #define cpu_has_xsave boot_cpu_has(X86_FEATURE_XSAVE)
 #endif
 
+#ifndef IPIPE_X86_FPU_EAGER
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4,2,0)
 #include <asm/i387.h>
 #include <asm/fpu-internal.h>
@@ -72,6 +73,9 @@ static inline void x86_fpregs_activate(struct task_struct *t)
 #define x86_xstate_alignment		__alignof__(union fpregs_state)
 
 #endif
+#else /* IPIPE_X86_FPU_EAGER */
+#define x86_xstate_alignment		__alignof__(union fpregs_state)
+#endif /* ! IPIPE_X86_FPU_EAGER */
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
 /*
@@ -465,9 +469,15 @@ void xnarch_leave_root(struct xnthread *root)
 	/* save fpregs from in-kernel use */
 	copy_fpregs_to_fpstate(rootcb->kfpu);
 	kernel_fpu_enable();
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,14,0)
+	/* restore current's fpregs */
+	__cpu_invalidate_fpregs_state();
+	switch_fpu_finish(&current->thread.fpu, smp_processor_id());
+#else
 	/* mark current thread as not owning the FPU anymore */
 	if (&current->thread.fpu.fpstate_active)
 		fpregs_deactivate(&current->thread.fpu);
+#endif
 }
 
 void xnarch_switch_fpu(struct xnthread *from, struct xnthread *to)
@@ -528,7 +538,11 @@ void xnarch_init_shadow_tcb(struct xnthread *thread)
 #else /* IPIPE_X86_FPU_EAGER */
 	/* XNFPU is always set */
 	xnthread_set_state(thread, XNFPU);
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,14,0)
 	fpu__activate_fpstate_read(&p->thread.fpu);
+#else
+	fpu__initialize(&p->thread.fpu);
+#endif
 #endif /* ! IPIPE_X86_FPU_EAGER */
 }
 
@@ -537,7 +551,12 @@ int mach_x86_thread_init(void)
 	xstate_cache = kmem_cache_create("cobalt_x86_xstate",
 					 fpu_kernel_xstate_size,
 					 x86_xstate_alignment,
-					 SLAB_NOTRACK, NULL);
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,14,0)
+					 SLAB_NOTRACK,
+#else
+					 0,
+#endif
+					 NULL);
 	if (xstate_cache == NULL)
 		return -ENOMEM;