On Fri, Apr 10, 2026 at 02:21:19PM +0200, Thomas Gleixner wrote: > The only remaining non-architecture usage of get_cycles() is to provide > random_get_entropy(). > > Switch s390 over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY and > providing random_get_entropy() in asm/random.h. > > Add 'asm/timex.h' includes to the relevant files, so the global include can > be removed once all architectures are converted over. > > Signed-off-by: Thomas Gleixner <[email protected]> > Cc: Heiko Carstens <[email protected]> > Cc: [email protected] > --- > arch/s390/Kconfig | 1 + > arch/s390/include/asm/random.h | 12 ++++++++++++ > arch/s390/include/asm/timex.h | 6 ------ > arch/s390/kernel/time.c | 1 + > arch/s390/kernel/vtime.c | 1 + > 5 files changed, 15 insertions(+), 6 deletions(-)
Acked-by: Heiko Carstens <[email protected]> Thomas, would you mind adding the below as minor improvement to this series? >From 7072e5d66b99a7fa666d17c6ad8cb254f2d8f473 Mon Sep 17 00:00:00 2001 From: Heiko Carstens <[email protected]> Date: Thu, 16 Apr 2026 15:08:15 +0200 Subject: [PATCH] s390: Use get_tod_clock_fast() for random_get_entropy() Use get_tod_clock_fast() instead of get_tod_clock_monotonic() to implement random_get_entropy(). There is no need for random_get_entropy() to provide monotonic increasing values, nor is there any need to provide (close to) nanosecond granularity timestamps by shifting the result. This slightly reduces the execution time of random_get_entropy() and adds two bits of randomness. Signed-off-by: Heiko Carstens <[email protected]> --- arch/s390/include/asm/random.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/include/asm/random.h b/arch/s390/include/asm/random.h index 7daf42dbed32..f6d9312efdbf 100644 --- a/arch/s390/include/asm/random.h +++ b/arch/s390/include/asm/random.h @@ -6,7 +6,7 @@ static inline unsigned long random_get_entropy(void) { - return (unsigned long)get_tod_clock_monotonic() >> 2; + return get_tod_clock_fast(); } #endif -- 2.51.0
