x86/gsseg: Move load_gs_index() to its own new header file

GS is a special segment on x86_64, move load_gs_index() to its own new
header file to simplify header inclusion.

No change in functionality.

Signed-off-by: H. Peter Anvin (Intel) <[e-mail]>
Signed-off-by: Xin Li <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/x86/include/asm/gsseg.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_X86_GSSEG_H
+#define _ASM_X86_GSSEG_H
+
+#include <linux/types.h>
+
+#include <asm/asm.h>
+#include <asm/cpufeature.h>
+#include <asm/alternative.h>
+#include <asm/processor.h>
+#include <asm/nops.h>
+
+#ifdef CONFIG_X86_64
+
+extern asmlinkage void asm_load_gs_index(u16 selector);
+
+static inline void native_load_gs_index(unsigned int selector)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	asm_load_gs_index(selector);
+	local_irq_restore(flags);
+}
+
+#endif /* CONFIG_X86_64 */
+
+#ifndef CONFIG_PARAVIRT_XXL
+
+static inline void load_gs_index(unsigned int selector)
+{
+#ifdef CONFIG_X86_64
+	native_load_gs_index(selector);
+#else
+	loadsegment(gs, selector);
+#endif
+}
+
+#endif /* CONFIG_PARAVIRT_XXL */
+
+#endif /* _ASM_X86_GSSEG_H */

arch/x86/include/asm/mmu_context.h

···
 #include <asm/tlbflush.h>
 #include <asm/paravirt.h>
 #include <asm/debugreg.h>
+#include <asm/gsseg.h>
 
 extern atomic64_t last_mm_ctx_id;
 

arch/x86/include/asm/special_insns.h

···
 	asm volatile("wbinvd": : :"memory");
 }
 
-extern asmlinkage void asm_load_gs_index(u16 selector);
-
-static inline void native_load_gs_index(unsigned int selector)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	asm_load_gs_index(selector);
-	local_irq_restore(flags);
-}
-
 static inline unsigned long __read_cr4(void)
 {
 	return native_read_cr4();
···
 static inline void wbinvd(void)
 {
 	native_wbinvd();
-}
-
-
-static inline void load_gs_index(unsigned int selector)
-{
-#ifdef CONFIG_X86_64
-	native_load_gs_index(selector);
-#else
-	loadsegment(gs, selector);
-#endif
 }
 
 #endif /* CONFIG_PARAVIRT_XXL */

arch/x86/kernel/paravirt.c

···
 #include <asm/special_insns.h>
 #include <asm/tlb.h>
 #include <asm/io_bitmap.h>
+#include <asm/gsseg.h>
 
 /*
  * nop stub, which must not clobber anything *including the stack* to

arch/x86/kernel/signal_32.c

···
 #include <asm/sigframe.h>
 #include <asm/sighandling.h>
 #include <asm/smap.h>
+#include <asm/gsseg.h>
 
 #ifdef CONFIG_IA32_EMULATION
 #include <asm/ia32_unistd.h>

arch/x86/kernel/tls.c

···
 #include <asm/ldt.h>
 #include <asm/processor.h>
 #include <asm/proto.h>
+#include <asm/gsseg.h>
 
 #include "tls.h"