Adrian Hunter 456e3788bc vdso: Make delta calculation overflow safe ...

Kernel timekeeping is designed to keep the change in cycles (since the last
timer interrupt) below max_cycles, which prevents multiplication overflow
when converting cycles to nanoseconds. However, if timer interrupts stop,
the calculation will eventually overflow.

Add protection against that, enabled by config option
CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT. Check against max_cycles, falling
back to a slower higher precision calculation.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240325064023.2997-8-adrian.hunter@intel.com

2024-04-08 15:03:07 +02:00

..

gettimeofday.c

vdso: Make delta calculation overflow safe

2024-04-08 15:03:07 +02:00

Kconfig

vdso: Add CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT

2024-04-08 15:03:06 +02:00

Makefile

vdso: Improve cmd_vdso_check to check all dynamic relocations

2023-03-21 21:15:34 +01:00