diff options
Diffstat (limited to 'arch/x86/kernel/process.c')
| -rw-r--r-- | arch/x86/kernel/process.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index cdf8e6694f71..afbe2eb4a1c6 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -443,6 +443,18 @@ static __always_inline void __speculation_ctrl_update(unsigned long tifp, wrmsrl(MSR_IA32_SPEC_CTRL, msr); } +static unsigned long speculation_ctrl_update_tif(struct task_struct *tsk) +{ + if (test_and_clear_tsk_thread_flag(tsk, TIF_SPEC_FORCE_UPDATE)) { + if (task_spec_ssb_disable(tsk)) + set_tsk_thread_flag(tsk, TIF_SSBD); + else + clear_tsk_thread_flag(tsk, TIF_SSBD); + } + /* Return the updated threadinfo flags*/ + return task_thread_info(tsk)->flags; +} + void speculation_ctrl_update(unsigned long tif) { /* Forced update. Make sure all relevant TIF flags are different */ @@ -451,6 +463,14 @@ void speculation_ctrl_update(unsigned long tif) preempt_enable(); } +/* Called from seccomp/prctl update */ +void speculation_ctrl_update_current(void) +{ + preempt_disable(); + speculation_ctrl_update(speculation_ctrl_update_tif(current)); + preempt_enable(); +} + void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p) { struct thread_struct *prev, *next; @@ -482,7 +502,15 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p) if ((tifp ^ tifn) & _TIF_NOCPUID) set_cpuid_faulting(!!(tifn & _TIF_NOCPUID)); - __speculation_ctrl_update(tifp, tifn); + if (likely(!((tifp | tifn) & _TIF_SPEC_FORCE_UPDATE))) { + __speculation_ctrl_update(tifp, tifn); + } else { + speculation_ctrl_update_tif(prev_p); + tifn = speculation_ctrl_update_tif(next_p); + + /* Enforce MSR update to ensure consistent state */ + __speculation_ctrl_update(~tifn, tifn); + } } /* |