Merge tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull vdso updates from Thomas Gleixner:

 - Make the handling of compat functions consistent and more robust

 - Rework the underlying data store so that it is dynamically allocated,
   which allows the conversion of the last holdout SPARC64 to the
   generic VDSO implementation

 - Rework the SPARC64 VDSO to utilize the generic implementation

 - Mop up the left overs of the non-generic VDSO support in the core
   code

 - Expand the VDSO selftest and make them more robust

 - Allow time namespaces to be enabled independently of the generic VDSO
   support, which was not possible before due to SPARC64 not using it

 - Various cleanups and improvements in the related code

* tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
  timens: Use task_lock guard in timens_get*()
  timens: Use mutex guard in proc_timens_set_offset()
  timens: Simplify some calls to put_time_ns()
  timens: Add a __free() wrapper for put_time_ns()
  timens: Remove dependency on the vDSO
  vdso/timens: Move functions to new file
  selftests: vDSO: vdso_test_correctness: Add a test for time()
  selftests: vDSO: vdso_test_correctness: Use facilities from parse_vdso.c
  selftests: vDSO: vdso_test_correctness: Handle different tv_usec types
  selftests: vDSO: vdso_test_correctness: Drop SYS_getcpu fallbacks
  selftests: vDSO: vdso_test_gettimeofday: Remove nolibc checks
  Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers"
  random: vDSO: Remove ifdeffery
  random: vDSO: Trim vDSO includes
  vdso/datapage: Trim down unnecessary includes
  vdso/datapage: Remove inclusion of gettimeofday.h
  vdso/helpers: Explicitly include vdso/processor.h
  vdso/gettimeofday: Add explicit includes
  random: vDSO: Add explicit includes
  MIPS: vdso: Explicitly include asm/vdso/vdso.h
  ...

6 files changed, 69 insertions, 49 deletions

diff --git a/include/asm-generic/bitsperlong.h b/include/asm-generic/bitsperlong.h
index 1023e2a4bd37..90e8aeebfd2f 100644
--- a/include/asm-generic/bitsperlong.h
+++ b/include/asm-generic/bitsperlong.h
@@ -19,6 +19,15 @@
 #error Inconsistent word size. Check asm/bitsperlong.h
 #endif
 
+#if __CHAR_BIT__ * __SIZEOF_LONG__ != __BITS_PER_LONG
+#error Inconsistent word size. Check asm/bitsperlong.h
+#endif
+
+#ifndef __ASSEMBLER__
+_Static_assert(sizeof(long) * 8 == __BITS_PER_LONG,
+	       "Inconsistent word size. Check asm/bitsperlong.h");
+#endif
+
 #ifndef BITS_PER_LONG_LONG
 #define BITS_PER_LONG_LONG 64
 #endif
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index ccf5c0ca26b7..7c38190b10bf 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -25,8 +25,7 @@ struct clocksource_base;
 struct clocksource;
 struct module;
 
-#if defined(CONFIG_ARCH_CLOCKSOURCE_DATA) || \
-    defined(CONFIG_GENERIC_GETTIMEOFDAY)
+#if defined(CONFIG_GENERIC_GETTIMEOFDAY)
 #include <asm/clocksource.h>
 #endif
 
@@ -103,9 +102,6 @@ struct clocksource {
 	u32			shift;
 	u64			max_idle_ns;
 	u32			maxadj;
-#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA
-	struct arch_clocksource_data archdata;
-#endif
 	u64			max_cycles;
 	u64			max_raw_delta;
 	const char		*name;
diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index c514d0e5a45c..58bd9728df58 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -8,6 +8,7 @@
 #include <linux/ns_common.h>
 #include <linux/err.h>
 #include <linux/time64.h>
+#include <linux/cleanup.h>
 
 struct user_namespace;
 extern struct user_namespace init_user_ns;
@@ -25,7 +26,9 @@ struct time_namespace {
 	struct ucounts		*ucounts;
 	struct ns_common	ns;
 	struct timens_offsets	offsets;
+#ifdef CONFIG_TIME_NS_VDSO
 	struct page		*vvar_page;
+#endif
 	/* If set prevents changing offsets after any task joined namespace. */
 	bool			frozen_offsets;
 } __randomize_layout;
@@ -38,9 +41,6 @@ static inline struct time_namespace *to_time_ns(struct ns_common *ns)
 	return container_of(ns, struct time_namespace, ns);
 }
 void __init time_ns_init(void);
-extern int vdso_join_timens(struct task_struct *task,
-			    struct time_namespace *ns);
-extern void timens_commit(struct task_struct *tsk, struct time_namespace *ns);
 
 static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
 {
@@ -53,7 +53,6 @@ struct time_namespace *copy_time_ns(u64 flags,
 				    struct time_namespace *old_ns);
 void free_time_ns(struct time_namespace *ns);
 void timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk);
-struct page *find_timens_vvar_page(struct vm_area_struct *vma);
 
 static inline void put_time_ns(struct time_namespace *ns)
 {
@@ -117,17 +116,6 @@ static inline void __init time_ns_init(void)
 {
 }
 
-static inline int vdso_join_timens(struct task_struct *task,
-				   struct time_namespace *ns)
-{
-	return 0;
-}
-
-static inline void timens_commit(struct task_struct *tsk,
-				 struct time_namespace *ns)
-{
-}
-
 static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
 {
 	return NULL;
@@ -154,11 +142,6 @@ static inline void timens_on_fork(struct nsproxy *nsproxy,
 	return;
 }
 
-static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
-{
-	return NULL;
-}
-
 static inline void timens_add_monotonic(struct timespec64 *ts) { }
 static inline void timens_add_boottime(struct timespec64 *ts) { }
 
@@ -175,4 +158,20 @@ static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
 }
 #endif
 
+#ifdef CONFIG_TIME_NS_VDSO
+extern void timens_commit(struct task_struct *tsk, struct time_namespace *ns);
+struct page *find_timens_vvar_page(struct vm_area_struct *vma);
+#else /* !CONFIG_TIME_NS_VDSO */
+static inline void timens_commit(struct task_struct *tsk, struct time_namespace *ns)
+{
+}
+
+static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
+{
+	return NULL;
+}
+#endif /* CONFIG_TIME_NS_VDSO */
+
+DEFINE_FREE(time_ns, struct time_namespace *, if (_T) put_time_ns(_T))
+
 #endif /* _LINUX_TIMENS_H */
diff --git a/include/linux/vdso_datastore.h b/include/linux/vdso_datastore.h
index a91fa24b06e0..0b530428db71 100644
--- a/include/linux/vdso_datastore.h
+++ b/include/linux/vdso_datastore.h
@@ -2,9 +2,15 @@
 #ifndef _LINUX_VDSO_DATASTORE_H
 #define _LINUX_VDSO_DATASTORE_H
 
+#ifdef CONFIG_HAVE_GENERIC_VDSO
 #include <linux/mm_types.h>
 
 extern const struct vm_special_mapping vdso_vvar_mapping;
 struct vm_area_struct *vdso_install_vvar_mapping(struct mm_struct *mm, unsigned long addr);
 
+void __init vdso_setup_data_pages(void);
+#else /* !CONFIG_HAVE_GENERIC_VDSO */
+static inline void vdso_setup_data_pages(void) { }
+#endif /* CONFIG_HAVE_GENERIC_VDSO */
+
 #endif /* _LINUX_VDSO_DATASTORE_H */
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 23c39b96190f..5977723fb3b5 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -4,24 +4,16 @@
 
 #ifndef __ASSEMBLY__
 
-#include <linux/compiler.h>
+#include <linux/types.h>
+
 #include <uapi/linux/bits.h>
 #include <uapi/linux/time.h>
-#include <uapi/linux/types.h>
-#include <uapi/asm-generic/errno-base.h>
 
 #include <vdso/align.h>
 #include <vdso/bits.h>
 #include <vdso/cache.h>
-#include <vdso/clocksource.h>
-#include <vdso/ktime.h>
-#include <vdso/limits.h>
-#include <vdso/math64.h>
 #include <vdso/page.h>
-#include <vdso/processor.h>
 #include <vdso/time.h>
-#include <vdso/time32.h>
-#include <vdso/time64.h>
 
 #ifdef CONFIG_ARCH_HAS_VDSO_TIME_DATA
 #include <asm/vdso/time_data.h>
@@ -80,8 +72,8 @@ struct vdso_timestamp {
  * @mask:		clocksource mask
  * @mult:		clocksource multiplier
  * @shift:		clocksource shift
- * @basetime[clock_id]:	basetime per clock_id
- * @offset[clock_id]:	time namespace offset per clock_id
+ * @basetime:		basetime per clock_id
+ * @offset:		time namespace offset per clock_id
  *
  * See also struct vdso_time_data for basic access and ordering information as
  * struct vdso_clock is used there.
@@ -184,17 +176,6 @@ enum vdso_pages {
 	VDSO_NR_PAGES
 };
 
-/*
- * The generic vDSO implementation requires that gettimeofday.h
- * provides:
- * - __arch_get_hw_counter(): to get the hw counter based on the
- *   clock_mode.
- * - gettimeofday_fallback(): fallback for gettimeofday.
- * - clock_gettime_fallback(): fallback for clock_gettime.
- * - clock_getres_fallback(): fallback for clock_getres.
- */
-#include <asm/vdso/gettimeofday.h>
-
 #else /* !__ASSEMBLY__ */
 
 #ifdef CONFIG_VDSO_GETRANDOM
diff --git a/include/vdso/helpers.h b/include/vdso/helpers.h
index 1a5ee9d9052c..a3bf4f1c0d37 100644
--- a/include/vdso/helpers.h
+++ b/include/vdso/helpers.h
@@ -6,6 +6,13 @@
 
 #include <asm/barrier.h>
 #include <vdso/datapage.h>
+#include <vdso/processor.h>
+#include <vdso/clocksource.h>
+
+static __always_inline bool vdso_is_timens_clock(const struct vdso_clock *vc)
+{
+	return IS_ENABLED(CONFIG_TIME_NS) && vc->clock_mode == VDSO_CLOCKMODE_TIMENS;
+}
 
 static __always_inline u32 vdso_read_begin(const struct vdso_clock *vc)
 {
@@ -18,6 +25,28 @@ static __always_inline u32 vdso_read_begin(const struct vdso_clock *vc)
 	return seq;
 }
 
+/*
+ * Variant of vdso_read_begin() to handle VDSO_CLOCKMODE_TIMENS.
+ *
+ * Time namespace enabled tasks have a special VVAR page installed which has
+ * vc->seq set to 1 and vc->clock_mode set to VDSO_CLOCKMODE_TIMENS. For non
+ * time namespace affected tasks this does not affect performance because if
+ * vc->seq is odd, i.e. a concurrent update is in progress the extra check for
+ * vc->clock_mode is just a few extra instructions while spin waiting for
+ * vc->seq to become even again.
+ */
+static __always_inline bool vdso_read_begin_timens(const struct vdso_clock *vc, u32 *seq)
+{
+	while (unlikely((*seq = READ_ONCE(vc->seq)) & 1)) {
+		if (vdso_is_timens_clock(vc))
+			return true;
+		cpu_relax();
+	}
+	smp_rmb();
+
+	return false;
+}
+
 static __always_inline u32 vdso_read_retry(const struct vdso_clock *vc,
 					   u32 start)
 {
@@ -25,7 +54,7 @@ static __always_inline u32 vdso_read_retry(const struct vdso_clock *vc,
 
 	smp_rmb();
 	seq = READ_ONCE(vc->seq);
-	return seq != start;
+	return unlikely(seq != start);
 }
 
 static __always_inline void vdso_write_seq_begin(struct vdso_clock *vc)