diff options
Diffstat (limited to 'arch/x86/mm/tlb.c')
| -rw-r--r-- | arch/x86/mm/tlb.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index ce104b962a17..dbbcfd59726a 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -214,6 +214,50 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, } /* + * Call this when reinitializing a CPU. It fixes the following potential + * problems: + * + * - The ASID changed from what cpu_tlbstate thinks it is (most likely + * because the CPU was taken down and came back up with CR3's PCID + * bits clear. CPU hotplug can do this. + * + * - The TLB contains junk in slots corresponding to inactive ASIDs. + * + * - The CPU went so far out to lunch that it may have missed a TLB + * flush. + */ +void initialize_tlbstate_and_flush(void) +{ + int i; + struct mm_struct *mm = this_cpu_read(cpu_tlbstate.loaded_mm); + u64 tlb_gen = atomic64_read(&init_mm.context.tlb_gen); + unsigned long cr3 = __read_cr3(); + + /* Assert that CR3 already references the right mm. */ + WARN_ON((cr3 & CR3_ADDR_MASK) != __pa(mm->pgd)); + + /* + * Assert that CR4.PCIDE is set if needed. (CR4.PCIDE initialization + * doesn't work like other CR4 bits because it can only be set from + * long mode.) + */ + WARN_ON(boot_cpu_has(X86_CR4_PCIDE) && + !(cr4_read_shadow() & X86_CR4_PCIDE)); + + /* Force ASID 0 and force a TLB flush. */ + write_cr3(cr3 & ~CR3_PCID_MASK); + + /* Reinitialize tlbstate. */ + this_cpu_write(cpu_tlbstate.loaded_mm_asid, 0); + this_cpu_write(cpu_tlbstate.next_asid, 1); + this_cpu_write(cpu_tlbstate.ctxs[0].ctx_id, mm->context.ctx_id); + this_cpu_write(cpu_tlbstate.ctxs[0].tlb_gen, tlb_gen); + + for (i = 1; i < TLB_NR_DYN_ASIDS; i++) + this_cpu_write(cpu_tlbstate.ctxs[i].ctx_id, 0); +} + +/* * flush_tlb_func_common()'s memory ordering requirement is that any * TLB fills that happen after we flush the TLB are ordered after we * read active_mm's tlb_gen. We don't need any explicit barriers |