[PATCH 1/7] x86/vdso: Respect COMPAT_32BIT_TIME

Thomas Weißschuh
2026-02-27T06:57:51Z

If CONFIG_COMPAT_32BIT_TIME is disabled then the vDSO should not
provide any 32-bit time related functionality. This is the intended
effect of the kconfig option and also the fallback system calls would
also not be implemented.

Currently the kconfig option does not affect the gettimeofday() syscall,
so also keep that in the vDSO.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
arch/x86/entry/vdso/common/vclock_gettime.c | 20 ++++++++++++--------
arch/x86/entry/vdso/vdso32/vdso32.lds.S | 4 +++-
2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/arch/x86/entry/vdso/common/vclock_gettime.c b/arch/x86/entry/vdso/common/vclock_gettime.c
index 027b7e88d753..664d91437f45 100644
--- a/arch/x86/entry/vdso/common/vclock_gettime.c
+++ b/arch/x86/entry/vdso/common/vclock_gettime.c
@@ -23,12 +23,14 @@ int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
int gettimeofday(struct __kernel_old_timeval *, struct timezone *)
__attribute__((weak, alias("__vdso_gettimeofday")));

+#if defined(__x86_64__) || defined(CONFIG_COMPAT_32BIT_TIME)
__kernel_old_time_t __vdso_time(__kernel_old_time_t *t)
{
return __cvdso_time(t);
}

__kernel_old_time_t time(__kernel_old_time_t *t) __attribute__((weak, alias("__vdso_time")));
+#endif /* CONFIG_COMPAT_32BIT_TIME */

#if defined(CONFIG_X86_64) && !defined(BUILD_VDSO32_64)
@@ -51,6 +53,7 @@ int clock_getres(clockid_t, struct __kernel_timespec *)

#else
/* i386 only */
+#ifdef CONFIG_COMPAT_32BIT_TIME
int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts)
{
return __cvdso_clock_gettime32(clock, ts);
@@ -59,14 +62,6 @@ int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts)
int clock_gettime(clockid_t, struct old_timespec32 *)
__attribute__((weak, alias("__vdso_clock_gettime")));

-int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts)
-{
- return __cvdso_clock_gettime(clock, ts);
-}
-
-int clock_gettime64(clockid_t, struct __kernel_timespec *)
- __attribute__((weak, alias("__vdso_clock_gettime64")));
-
int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res)
{
return __cvdso_clock_getres_time32(clock, res);
@@ -74,6 +69,15 @@ int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res)

int clock_getres(clockid_t, struct old_timespec32 *)
__attribute__((weak, alias("__vdso_clock_getres")));
+#endif /* CONFIG_COMPAT_32BIT_TIME */
+
+int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts)
+{
+ return __cvdso_clock_gettime(clock, ts);
+}
+
+int clock_gettime64(clockid_t, struct __kernel_timespec *)
+ __attribute__((weak, alias("__vdso_clock_gettime64")));

int __vdso_clock_getres_time64(clockid_t clock, struct __kernel_timespec *ts)
{
diff --git a/arch/x86/entry/vdso/vdso32/vdso32.lds.S b/arch/x86/entry/vdso/vdso32/vdso32.lds.S
index 55554f80d930..012bc3a62aca 100644
--- a/arch/x86/entry/vdso/vdso32/vdso32.lds.S
+++ b/arch/x86/entry/vdso/vdso32/vdso32.lds.S
@@ -23,10 +23,12 @@ VERSION
{
LINUX_2.6 {
global:
+#ifdef CONFIG_COMPAT_32BIT_TIME
__vdso_clock_gettime;
- __vdso_gettimeofday;
__vdso_time;
__vdso_clock_getres;
+#endif /* CONFIG_COMPAT_32BIT_TIME */
+ __vdso_gettimeofday;
__vdso_clock_gettime64;
__vdso_clock_getres_time64;
__vdso_getcpu;

--
2.53.0