From 1f562beba75c9da65461debbdb5d8d2871ab38a1 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Fri, 10 May 2019 00:46:25 +0100 Subject: sched: Add sched_smt_active() Add the sched_smt_active() function needed for some x86 speculation mitigations. This was introduced upstream by commits 1b568f0aabf2 "sched/core: Optimize SCHED_SMT", ba2591a5993e "sched/smt: Update sched_smt_present at runtime", c5511d03ec09 "sched/smt: Make sched_smt_present track topology", and 321a874a7ef8 "sched/smt: Expose sched_smt_present static key". The upstream implementation uses the static_key_{disable,enable}_cpuslocked() functions, which aren't practical to backport. Signed-off-by: Ben Hutchings Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Peter Zijlstra (Intel) Cc: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman --- include/linux/sched/smt.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 include/linux/sched/smt.h (limited to 'include/linux') diff --git a/include/linux/sched/smt.h b/include/linux/sched/smt.h new file mode 100644 index 000000000000..5209c268c6fd --- /dev/null +++ b/include/linux/sched/smt.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_SCHED_SMT_H +#define _LINUX_SCHED_SMT_H + +#include + +#ifdef CONFIG_SCHED_SMT +extern atomic_t sched_smt_present; + +static __always_inline bool sched_smt_active(void) +{ + return atomic_read(&sched_smt_present); +} +#else +static inline bool sched_smt_active(void) { return false; } +#endif + +#endif -- cgit v1.2.3