From cb81deefb59de01325ab822f900c13941bfaf67f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 28 Feb 2024 23:13:00 +0100 Subject: x86/idle: Sanitize X86_BUG_AMD_E400 handling amd_e400_idle(), the idle routine for AMD CPUs which are affected by erratum 400 violates the RCU constraints by invoking tick_broadcast_enter() and tick_broadcast_exit() after the core code has marked RCU non-idle. The functions can end up in lockdep or tracing, which rightfully triggers a RCU warning. The core code provides now a static branch conditional invocation of the broadcast functions. Remove amd_e400_idle(), enforce default_idle() and enable the static branch on affected CPUs to cure this. [ bp: Fold in a fix for a IS_ENABLED() check fail missing a "CONFIG_" prefix which tglx spotted. ] Reported-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/877cim6sis.ffs@tglx --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/Kconfig') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 502986237cb6..080265369f8e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -147,6 +147,7 @@ config X86 select EDAC_ATOMIC_SCRUB select EDAC_SUPPORT select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) + select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST select GENERIC_CLOCKEVENTS_MIN_ADJUST select GENERIC_CMOS_UPDATE select GENERIC_CPU_AUTOPROBE -- cgit v1.2.3