[icp] fpu and asm cleanup for linux

Properly annotate functions and data section so that objtool does not complain
when CONFIG_STACK_VALIDATION and CONFIG_FRAME_POINTER are enabled.

Pass KERNELCPPFLAGS to assembler.

Use kfpu_begin()/kfpu_end() to protect SIMD regions in Linux kernel.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Closes #5872 
Closes #5041

module/icp/algs/modes/gcm.c

@@ -22,6 +22,17 @@
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
+#if defined(_KERNEL) && defined(__amd64)
+#include <linux/simd_x86.h>
+
+#define	KPREEMPT_DISABLE	kfpu_begin()
+#define	KPREEMPT_ENABLE		kfpu_end()
+
+#else
+#define	KPREEMPT_DISABLE
+#define	KPREEMPT_ENABLE
+#endif	/* _KERNEL */
+
 #include <sys/zfs_context.h>
 #include <modes/modes.h>
 #include <sys/crypto/common.h>
@@ -30,16 +41,6 @@
 
 #ifdef __amd64
 
-#ifdef _KERNEL
-/* Workaround for no XMM kernel thread save/restore */
-#define	KPREEMPT_DISABLE	kpreempt_disable()
-#define	KPREEMPT_ENABLE		kpreempt_enable()
-
-#else
-#define	KPREEMPT_DISABLE
-#define	KPREEMPT_ENABLE
-#endif	/* _KERNEL */
-
 extern void gcm_mul_pclmulqdq(uint64_t *x_in, uint64_t *y, uint64_t *res);
 static int intel_pclmulqdq_instruction_present(void);
 #endif	/* __amd64 */