[tip: timers/core] vdso: Add CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT

[tip-bot2 for Adrian Hunter]

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     0c68458b0a5878d735572b4f4d91219a1db7c784
Gitweb:        https://git.kernel.org/tip/0c68458b0a5878d735572b4f4d91219a1db7c784
Author:        Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate:    Mon, 25 Mar 2024 08:40:07 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 08 Apr 2024 15:03:06 +02:00

vdso: Add CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT

Add CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT in preparation to add
multiplication overflow protection to the VDSO time getter functions.

Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240325064023.2997-4-adrian.hunter@xxxxxxxxx

---
 lib/vdso/Kconfig | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig
index d883ac2..c46c230 100644
--- a/lib/vdso/Kconfig
+++ b/lib/vdso/Kconfig
@@ -30,4 +30,11 @@ config GENERIC_VDSO_TIME_NS
 	  Selected by architectures which support time namespaces in the
 	  VDSO
 
+config GENERIC_VDSO_OVERFLOW_PROTECT
+	bool
+	help
+	  Select to add multiplication overflow protection to the VDSO
+	  time getter functions for the price of an extra conditional
+	  in the hotpath.
+
 endif