From: Arnd Bergmann <arnd@arndb.de>

Two functions in the 32-bit doublefault code are lacking a prototype:

arch/x86/kernel/doublefault_32.c:23:36: error: no previous prototype for 'doublefault_shim' [-Werror=missing-prototypes]
   23 | asmlinkage noinstr void __noreturn doublefault_shim(void)
      |                                    ^~~~~~~~~~~~~~~~
arch/x86/kernel/doublefault_32.c:114:6: error: no previous prototype for 'doublefault_init_cpu_tss' [-Werror=missing-prototypes]
  114 | void doublefault_init_cpu_tss(void)

The first one is only called from assembler, while the second one is
declared in doublefault.h, but this file is not included.

Include the header file and add the other declaration there as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/x86/include/asm/doublefault.h | 4 ++++
 arch/x86/kernel/doublefault_32.c   | 1 +
 2 files changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/doublefault.h b/arch/x86/include/asm/doublefault.h
index 54a6e4a2e132..de0e88b32207 100644
--- a/arch/x86/include/asm/doublefault.h
+++ b/arch/x86/include/asm/doublefault.h

@@ -2,6 +2,8 @@
 #ifndef _ASM_X86_DOUBLEFAULT_H
 #define _ASM_X86_DOUBLEFAULT_H
 
+#include <linux/linkage.h>
+
 #ifdef CONFIG_X86_32
 extern void doublefault_init_cpu_tss(void);
 #else

@@ -10,4 +12,6 @@ static inline void doublefault_init_cpu_tss(void)
 }
 #endif
 
+asmlinkage void __noreturn doublefault_shim(void);
+
 #endif /* _ASM_X86_DOUBLEFAULT_H */

diff --git a/arch/x86/kernel/doublefault_32.c b/arch/x86/kernel/doublefault_32.c
index 3b58d8703094..6eaf9a6bc02f 100644
--- a/arch/x86/kernel/doublefault_32.c
+++ b/arch/x86/kernel/doublefault_32.c

@@ -9,6 +9,7 @@
 #include <asm/processor.h>
 #include <asm/desc.h>
 #include <asm/traps.h>
+#include <asm/doublefault.h>
 
 #define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM)
 

-- 
2.39.2