diff options
Diffstat (limited to 'arch/x86/mm/tlb.c')
| -rw-r--r-- | arch/x86/mm/tlb.c | 80 |
1 files changed, 64 insertions, 16 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 593d2f76a54c..ce104b962a17 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -30,6 +30,40 @@ atomic64_t last_mm_ctx_id = ATOMIC64_INIT(1); +static void choose_new_asid(struct mm_struct *next, u64 next_tlb_gen, + u16 *new_asid, bool *need_flush) +{ + u16 asid; + + if (!static_cpu_has(X86_FEATURE_PCID)) { + *new_asid = 0; + *need_flush = true; + return; + } + + for (asid = 0; asid < TLB_NR_DYN_ASIDS; asid++) { + if (this_cpu_read(cpu_tlbstate.ctxs[asid].ctx_id) != + next->context.ctx_id) + continue; + + *new_asid = asid; + *need_flush = (this_cpu_read(cpu_tlbstate.ctxs[asid].tlb_gen) < + next_tlb_gen); + return; + } + + /* + * We don't currently own an ASID slot on this CPU. + * Allocate a slot. + */ + *new_asid = this_cpu_add_return(cpu_tlbstate.next_asid, 1) - 1; + if (*new_asid >= TLB_NR_DYN_ASIDS) { + *new_asid = 0; + this_cpu_write(cpu_tlbstate.next_asid, 1); + } + *need_flush = true; +} + void leave_mm(int cpu) { struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm); @@ -65,6 +99,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) { struct mm_struct *real_prev = this_cpu_read(cpu_tlbstate.loaded_mm); + u16 prev_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid); unsigned cpu = smp_processor_id(); u64 next_tlb_gen; @@ -84,12 +119,13 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, /* * Verify that CR3 is what we think it is. This will catch * hypothetical buggy code that directly switches to swapper_pg_dir - * without going through leave_mm() / switch_mm_irqs_off(). + * without going through leave_mm() / switch_mm_irqs_off() or that + * does something like write_cr3(read_cr3_pa()). */ - VM_BUG_ON(read_cr3_pa() != __pa(real_prev->pgd)); + VM_BUG_ON(__read_cr3() != (__sme_pa(real_prev->pgd) | prev_asid)); if (real_prev == next) { - VM_BUG_ON(this_cpu_read(cpu_tlbstate.ctxs[0].ctx_id) != + VM_BUG_ON(this_cpu_read(cpu_tlbstate.ctxs[prev_asid].ctx_id) != next->context.ctx_id); if (cpumask_test_cpu(cpu, mm_cpumask(next))) { @@ -106,16 +142,17 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, cpumask_set_cpu(cpu, mm_cpumask(next)); next_tlb_gen = atomic64_read(&next->context.tlb_gen); - if (this_cpu_read(cpu_tlbstate.ctxs[0].tlb_gen) < next_tlb_gen) { + if (this_cpu_read(cpu_tlbstate.ctxs[prev_asid].tlb_gen) < + next_tlb_gen) { /* * Ideally, we'd have a flush_tlb() variant that * takes the known CR3 value as input. This would * be faster on Xen PV and on hypothetical CPUs * on which INVPCID is fast. */ - this_cpu_write(cpu_tlbstate.ctxs[0].tlb_gen, + this_cpu_write(cpu_tlbstate.ctxs[prev_asid].tlb_gen, next_tlb_gen); - write_cr3(__sme_pa(next->pgd)); + write_cr3(__sme_pa(next->pgd) | prev_asid); trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); } @@ -126,8 +163,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, * are not reflected in tlb_gen.) */ } else { - VM_BUG_ON(this_cpu_read(cpu_tlbstate.ctxs[0].ctx_id) == - next->context.ctx_id); + u16 new_asid; + bool need_flush; if (IS_ENABLED(CONFIG_VMAP_STACK)) { /* @@ -154,12 +191,22 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, cpumask_set_cpu(cpu, mm_cpumask(next)); next_tlb_gen = atomic64_read(&next->context.tlb_gen); - this_cpu_write(cpu_tlbstate.ctxs[0].ctx_id, next->context.ctx_id); - this_cpu_write(cpu_tlbstate.ctxs[0].tlb_gen, next_tlb_gen); - this_cpu_write(cpu_tlbstate.loaded_mm, next); - write_cr3(__sme_pa(next->pgd)); + choose_new_asid(next, next_tlb_gen, &new_asid, &need_flush); - trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); + if (need_flush) { + this_cpu_write(cpu_tlbstate.ctxs[new_asid].ctx_id, next->context.ctx_id); + this_cpu_write(cpu_tlbstate.ctxs[new_asid].tlb_gen, next_tlb_gen); + write_cr3(__sme_pa(next->pgd) | new_asid); + trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, + TLB_FLUSH_ALL); + } else { + /* The new ASID is already up to date. */ + write_cr3(__sme_pa(next->pgd) | new_asid | CR3_NOFLUSH); + trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, 0); + } + + this_cpu_write(cpu_tlbstate.loaded_mm, next); + this_cpu_write(cpu_tlbstate.loaded_mm_asid, new_asid); } load_mm_cr4(next); @@ -186,13 +233,14 @@ static void flush_tlb_func_common(const struct flush_tlb_info *f, * wants us to catch up to. */ struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm); + u32 loaded_mm_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid); u64 mm_tlb_gen = atomic64_read(&loaded_mm->context.tlb_gen); - u64 local_tlb_gen = this_cpu_read(cpu_tlbstate.ctxs[0].tlb_gen); + u64 local_tlb_gen = this_cpu_read(cpu_tlbstate.ctxs[loaded_mm_asid].tlb_gen); /* This code cannot presently handle being reentered. */ VM_WARN_ON(!irqs_disabled()); - VM_WARN_ON(this_cpu_read(cpu_tlbstate.ctxs[0].ctx_id) != + VM_WARN_ON(this_cpu_read(cpu_tlbstate.ctxs[loaded_mm_asid].ctx_id) != loaded_mm->context.ctx_id); if (!cpumask_test_cpu(smp_processor_id(), mm_cpumask(loaded_mm))) { @@ -280,7 +328,7 @@ static void flush_tlb_func_common(const struct flush_tlb_info *f, } /* Both paths above update our state to mm_tlb_gen. */ - this_cpu_write(cpu_tlbstate.ctxs[0].tlb_gen, mm_tlb_gen); + this_cpu_write(cpu_tlbstate.ctxs[loaded_mm_asid].tlb_gen, mm_tlb_gen); } static void flush_tlb_func_local(void *info, enum tlb_flush_reason reason) |