diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2019-05-10 00:46:25 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-16 19:45:11 +0200 |
| commit | 1f562beba75c9da65461debbdb5d8d2871ab38a1 (patch) | |
| tree | 55b8dcb09e8ee6882de22c9fa7abf59d3e8ec6e5 /include/linux/sched | |
| parent | f576a78075bae5799b6c29f7e7548003e89361da (diff) | |
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 <ben@decadent.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/sched')
| -rw-r--r-- | include/linux/sched/smt.h | 18 |
1 files changed, 18 insertions, 0 deletions
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 <linux/atomic.h> + +#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 |