diff options
| -rw-r--r-- | arch/x86/kernel/process_64.c | 29 | ||||
| -rw-r--r-- | arch/x86/mm/tlb.c | 7 |
2 files changed, 29 insertions, 7 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 6d3d20e3e43a..d8d582b750d4 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -798,6 +798,27 @@ static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr) #define LAM_U57_BITS 6 +static void enable_lam_func(void *__mm) +{ + struct mm_struct *mm = __mm; + + if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm) { + write_cr3(__read_cr3() | mm->context.lam_cr3_mask); + set_tlbstate_lam_mode(mm); + } +} + +static void mm_enable_lam(struct mm_struct *mm) +{ + /* + * Even though the process must still be single-threaded at this + * point, kernel threads may be using the mm. IPI those kernel + * threads if they exist. + */ + on_each_cpu_mask(mm_cpumask(mm), enable_lam_func, mm, true); + set_bit(MM_CONTEXT_LOCK_LAM, &mm->context.flags); +} + static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits) { if (!cpu_feature_enabled(X86_FEATURE_LAM)) @@ -814,6 +835,10 @@ static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits) if (mmap_write_lock_killable(mm)) return -EINTR; + /* + * MM_CONTEXT_LOCK_LAM is set on clone. Prevent LAM from + * being enabled unless the process is single threaded: + */ if (test_bit(MM_CONTEXT_LOCK_LAM, &mm->context.flags)) { mmap_write_unlock(mm); return -EBUSY; @@ -830,9 +855,7 @@ static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits) return -EINVAL; } - write_cr3(__read_cr3() | mm->context.lam_cr3_mask); - set_tlbstate_lam_mode(mm); - set_bit(MM_CONTEXT_LOCK_LAM, &mm->context.flags); + mm_enable_lam(mm); mmap_write_unlock(mm); diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 44ac64f3a047..a041d2ecd838 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -503,9 +503,9 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, { struct mm_struct *prev = this_cpu_read(cpu_tlbstate.loaded_mm); u16 prev_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid); - unsigned long new_lam = mm_lam_cr3_mask(next); bool was_lazy = this_cpu_read(cpu_tlbstate_shared.is_lazy); unsigned cpu = smp_processor_id(); + unsigned long new_lam; u64 next_tlb_gen; bool need_flush; u16 new_asid; @@ -619,9 +619,7 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, cpumask_clear_cpu(cpu, mm_cpumask(prev)); } - /* - * Start remote flushes and then read tlb_gen. - */ + /* Start receiving IPIs and then read tlb_gen (and LAM below) */ if (next != &init_mm) cpumask_set_cpu(cpu, mm_cpumask(next)); next_tlb_gen = atomic64_read(&next->context.tlb_gen); @@ -633,6 +631,7 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, barrier(); } + new_lam = mm_lam_cr3_mask(next); set_tlbstate_lam_mode(next); if (need_flush) { this_cpu_write(cpu_tlbstate.ctxs[new_asid].ctx_id, next->context.ctx_id); |