[PATCH v2 9/9] vdso/gettimeofday: Verify COMPAT_32BIT_TIME interactions

["Thomas Weißschuh" <thomas.weissschuh@linutronix.de>]

If CONFIG_COMPAT_32BIT_TIME is disabled then the vDSO should not
provide any 32-bit time related functionality.

Add some build-time validations to make sure the architecture-specific
glue satisfies this requirement.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 lib/vdso/gettimeofday.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index b8c1fc85eb74..f7a591aba59f 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -25,6 +25,8 @@
  */
 #include <asm/vdso/gettimeofday.h>
 
+#include <linux/build_bug.h>
+
 /* Bring in default accessors */
 #include <vdso/vsyscall.h>
 
@@ -325,6 +327,8 @@ __cvdso_clock_gettime32_data(const struct vdso_time_data *vd, clockid_t clock,
 	struct __kernel_timespec ts;
 	bool ok;
 
+	BUILD_BUG_ON(!IS_ENABLED(CONFIG_COMPAT_32BIT_TIME));
+
 	ok = __cvdso_clock_gettime_common(vd, clock, &ts);
 
 	if (unlikely(!ok))
@@ -354,6 +358,8 @@ __cvdso_gettimeofday_data(const struct vdso_time_data *vd,
 	BUILD_BUG();
 #endif
 
+	BUILD_BUG_ON(sizeof(tv->tv_sec) != 8 && !IS_ENABLED(CONFIG_COMPAT_32BIT_TIME));
+
 	if (likely(tv != NULL)) {
 		struct __kernel_timespec ts;
 
@@ -392,6 +398,8 @@ __cvdso_time_data(const struct vdso_time_data *vd, __kernel_old_time_t *time)
 	BUILD_BUG();
 #endif
 
+	BUILD_BUG_ON(sizeof(*time) != 8 && !IS_ENABLED(CONFIG_COMPAT_32BIT_TIME));
+
 	if (vdso_is_timens_clock(vc)) {
 		vd = vdso_timens_data(vd);
 		vc = vd->clock_data;
@@ -481,6 +489,8 @@ __cvdso_clock_getres_time32_data(const struct vdso_time_data *vd, clockid_t cloc
 	struct __kernel_timespec ts;
 	bool ok;
 
+	BUILD_BUG_ON(!IS_ENABLED(CONFIG_COMPAT_32BIT_TIME));
+
 	ok = __cvdso_clock_getres_common(vd, clock, &ts);
 
 	if (unlikely(!ok))

-- 
2.55.0