mirror of
https://github.com/torvalds/linux.git
synced 2024-12-14 23:25:54 +00:00
aa77bfb354
STIBP stands for Single Thread Indirect Branch Predictors. The acronym, however, can be easily mis-spelled as STIPB. It is perhaps due to the presence of another related term - IBPB (Indirect Branch Predictor Barrier). Fix the mis-spelling in the code. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: KarimAllah Ahmed <karahmed@amazon.de> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/1544039368-9009-1-git-send-email-longman@redhat.com
40 lines
1.1 KiB
C
40 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
//
|
|
// Code shared between 32 and 64 bit
|
|
|
|
#include <asm/spec-ctrl.h>
|
|
|
|
void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p);
|
|
|
|
/*
|
|
* This needs to be inline to optimize for the common case where no extra
|
|
* work needs to be done.
|
|
*/
|
|
static inline void switch_to_extra(struct task_struct *prev,
|
|
struct task_struct *next)
|
|
{
|
|
unsigned long next_tif = task_thread_info(next)->flags;
|
|
unsigned long prev_tif = task_thread_info(prev)->flags;
|
|
|
|
if (IS_ENABLED(CONFIG_SMP)) {
|
|
/*
|
|
* Avoid __switch_to_xtra() invocation when conditional
|
|
* STIBP is disabled and the only different bit is
|
|
* TIF_SPEC_IB. For CONFIG_SMP=n TIF_SPEC_IB is not
|
|
* in the TIF_WORK_CTXSW masks.
|
|
*/
|
|
if (!static_branch_likely(&switch_to_cond_stibp)) {
|
|
prev_tif &= ~_TIF_SPEC_IB;
|
|
next_tif &= ~_TIF_SPEC_IB;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* __switch_to_xtra() handles debug registers, i/o bitmaps,
|
|
* speculation mitigations etc.
|
|
*/
|
|
if (unlikely(next_tif & _TIF_WORK_CTXSW_NEXT ||
|
|
prev_tif & _TIF_WORK_CTXSW_PREV))
|
|
__switch_to_xtra(prev, next);
|
|
}
|