diff options
Diffstat (limited to 'arch/x86/kernel/process.c')
| -rw-r--r-- | arch/x86/kernel/process.c | 39 |
1 files changed, 21 insertions, 18 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index ce6cd220f722..f362ce0d5ac0 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -545,28 +545,20 @@ static __always_inline void __speculation_ctrl_update(unsigned long tifp, lockdep_assert_irqs_disabled(); - /* - * If TIF_SSBD is different, select the proper mitigation - * method. Note that if SSBD mitigation is disabled or permanentely - * enabled this branch can't be taken because nothing can set - * TIF_SSBD. - */ - if (tif_diff & _TIF_SSBD) { - if (static_cpu_has(X86_FEATURE_VIRT_SSBD)) { + /* Handle change of TIF_SSBD depending on the mitigation method. */ + if (static_cpu_has(X86_FEATURE_VIRT_SSBD)) { + if (tif_diff & _TIF_SSBD) amd_set_ssb_virt_state(tifn); - } else if (static_cpu_has(X86_FEATURE_LS_CFG_SSBD)) { + } else if (static_cpu_has(X86_FEATURE_LS_CFG_SSBD)) { + if (tif_diff & _TIF_SSBD) amd_set_core_ssb_state(tifn); - } else if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) || - static_cpu_has(X86_FEATURE_AMD_SSBD)) { - msr |= ssbd_tif_to_spec_ctrl(tifn); - updmsr = true; - } + } else if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) || + static_cpu_has(X86_FEATURE_AMD_SSBD)) { + updmsr |= !!(tif_diff & _TIF_SSBD); + msr |= ssbd_tif_to_spec_ctrl(tifn); } - /* - * Only evaluate TIF_SPEC_IB if conditional STIBP is enabled, - * otherwise avoid the MSR write. - */ + /* Only evaluate TIF_SPEC_IB if conditional STIBP is enabled. */ if (IS_ENABLED(CONFIG_SMP) && static_branch_unlikely(&switch_to_cond_stibp)) { updmsr |= !!(tif_diff & _TIF_SPEC_IB); @@ -612,6 +604,17 @@ void speculation_ctrl_update_current(void) preempt_enable(); } +static inline void cr4_toggle_bits_irqsoff(unsigned long mask) +{ + unsigned long newval, cr4 = this_cpu_read(cpu_tlbstate.cr4); + + newval = cr4 ^ mask; + if (newval != cr4) { + this_cpu_write(cpu_tlbstate.cr4, newval); + __write_cr4(newval); + } +} + void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p) { unsigned long tifp, tifn; |