arch: vdso: consolidate gettime prototypes

The VDSO functions are defined as globals in the kernel sources but intended
to be called from userspace, so there is no need to declare them in a kernel
side header.

Without a prototype, this now causes warnings such as

arch/mips/vdso/vgettimeofday.c:14:5: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:28:5: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:36:5: error: no previous prototype for '__vdso_clock_getres' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:42:5: error: no previous prototype for '__vdso_clock_gettime64' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:254:1: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:282:1: error: no previous prototype for '__vdso_clock_gettime_stick' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:307:1: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:343:1: error: no previous prototype for '__vdso_gettimeofday_stick' [-Werror=missing-prototypes]

Most architectures have already added workarounds for these by adding
declarations somewhere, but since these are all compatible, we should
really just have one copy, with an #ifdef check for the 32-bit vs
64-bit variant and use that everywhere.

Unfortunately, the sparc an um versions are currently incompatible
since they never added support for __vdso_clock_gettime64() in 32-bit
userland. For the moment, I'm leaving this one out, as I can't
easily test it and it requires a larger rework.

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/include/asm/vdso.h

@@ -24,11 +24,6 @@ static inline void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
 
 #endif /* CONFIG_VDSO */
 
-int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts);
-int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts);
-int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
-int __vdso_clock_getres(clockid_t clock_id, struct old_timespec32 *res);
-
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */

arch/arm/vdso/vgettimeofday.c

@@ -8,6 +8,7 @@
 #include <linux/types.h>
 #include <asm/vdso.h>
 #include <asm/unwind.h>
+#include <vdso/gettime.h>
 
 int __vdso_clock_gettime(clockid_t clock,
 			 struct old_timespec32 *ts)

arch/arm64/kernel/vdso32/vgettimeofday.c

@@ -5,6 +5,7 @@
  * Copyright (C) 2018 ARM Limited
  *
  */
+#include <vdso/gettime.h>
 
 int __vdso_clock_gettime(clockid_t clock,
 			 struct old_timespec32 *ts)

arch/csky/kernel/vdso/vgettimeofday.c

@@ -2,36 +2,27 @@
 
 #include <linux/time.h>
 #include <linux/types.h>
+#include <vdso/gettime.h>
 
 extern
-int __vdso_clock_gettime(clockid_t clock,
-			 struct old_timespec32 *ts);
 int __vdso_clock_gettime(clockid_t clock,
 			 struct old_timespec32 *ts)
 {
 	return __cvdso_clock_gettime32(clock, ts);
 }
 
-int __vdso_clock_gettime64(clockid_t clock,
-			   struct __kernel_timespec *ts);
 int __vdso_clock_gettime64(clockid_t clock,
 			   struct __kernel_timespec *ts)
 {
 	return __cvdso_clock_gettime(clock, ts);
 }
 
-extern
-int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
-			struct timezone *tz);
 int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
 			struct timezone *tz)
 {
 	return __cvdso_gettimeofday(tv, tz);
 }
 
-extern
-int __vdso_clock_getres(clockid_t clock_id,
-			struct old_timespec32 *res);
 int __vdso_clock_getres(clockid_t clock_id,
 			struct old_timespec32 *res)
 {

arch/loongarch/vdso/vgettimeofday.c

@@ -5,23 +5,18 @@
  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
  */
 #include <linux/types.h>
+#include <vdso/gettime.h>
 
-extern
-int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
 int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
 {
 	return __cvdso_clock_gettime(clock, ts);
 }
 
-extern
-int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
 int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
 {
 	return __cvdso_gettimeofday(tv, tz);
 }
 
-extern
-int __vdso_clock_getres(clockid_t clock_id, struct __kernel_timespec *res);
 int __vdso_clock_getres(clockid_t clock_id, struct __kernel_timespec *res)
 {
 	return __cvdso_clock_getres(clock_id, res);

arch/mips/vdso/vgettimeofday.c

@@ -9,6 +9,7 @@
  */
 #include <linux/time.h>
 #include <linux/types.h>
+#include <vdso/gettime.h>
 
 #if _MIPS_SIM != _MIPS_SIM_ABI64
 int __vdso_clock_gettime(clockid_t clock,

arch/riscv/kernel/vdso/vgettimeofday.c

@@ -8,23 +8,18 @@
 
 #include <linux/time.h>
 #include <linux/types.h>
+#include <vdso/gettime.h>
 
-extern
-int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
 int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
 {
 	return __cvdso_clock_gettime(clock, ts);
 }
 
-extern
-int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
 int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
 {
 	return __cvdso_gettimeofday(tv, tz);
 }
 
-extern
-int __vdso_clock_getres(clockid_t clock_id, struct __kernel_timespec *res);
 int __vdso_clock_getres(clockid_t clock_id, struct __kernel_timespec *res)
 {
 	return __cvdso_clock_getres(clock_id, res);

arch/x86/entry/vdso/vclock_gettime.c

@@ -11,12 +11,10 @@
 #include <linux/time.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
+#include <vdso/gettime.h>
 
 #include "../../../../lib/vdso/gettimeofday.c"
 
-extern int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
-extern __kernel_old_time_t __vdso_time(__kernel_old_time_t *t);
-
 int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
 {
 	return __cvdso_gettimeofday(tv, tz);
@@ -35,9 +33,6 @@ __kernel_old_time_t time(__kernel_old_time_t *t)	__attribute__((weak, alias("__v
 
 #if defined(CONFIG_X86_64) && !defined(BUILD_VDSO32_64)
 /* both 64-bit and x32 use these */
-extern int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
-extern int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res);
-
 int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
 {
 	return __cvdso_clock_gettime(clock, ts);
@@ -56,9 +51,6 @@ int clock_getres(clockid_t, struct __kernel_timespec *)
 
 #else
 /* i386 only */
-extern int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts);
-extern int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res);
-
 int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts)
 {
 	return __cvdso_clock_gettime32(clock, ts);

arch/x86/include/asm/vdso/gettimeofday.h

@@ -337,8 +337,6 @@ u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult)
 }
 #define vdso_calc_delta vdso_calc_delta
 
-int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts);
-
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_VDSO_GETTIMEOFDAY_H */

include/vdso/gettime.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _VDSO_GETTIME_H
+#define _VDSO_GETTIME_H
+
+#include <linux/types.h>
+
+struct __kernel_timespec;
+struct timezone;
+
+#if !defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64)
+struct old_timespec32;
+int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res);
+int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts);
+#else
+int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res);
+int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
+#endif
+
+__kernel_old_time_t __vdso_time(__kernel_old_time_t *t);
+int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
+int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts);
+
+#endif