diff options
Diffstat (limited to 'arch/x86/include/asm/tlbflush.h')
| -rw-r--r-- | arch/x86/include/asm/tlbflush.h | 65 |
1 files changed, 55 insertions, 10 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 511bf5fae8b8..323a313947e0 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -159,8 +159,16 @@ struct tlb_state { * are on. This means that it may not match current->active_mm, * which will contain the previous user mm when we're in lazy TLB * mode even if we've already switched back to swapper_pg_dir. + * + * During switch_mm_irqs_off(), loaded_mm will be set to + * LOADED_MM_SWITCHING during the brief interrupts-off window + * when CR3 and loaded_mm would otherwise be inconsistent. This + * is for nmi_uaccess_okay()'s benefit. */ struct mm_struct *loaded_mm; + +#define LOADED_MM_SWITCHING ((struct mm_struct *)1) + u16 loaded_mm_asid; u16 next_asid; /* last user mm's ctx id */ @@ -230,6 +238,38 @@ struct tlb_state { }; DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate); +/* + * Blindly accessing user memory from NMI context can be dangerous + * if we're in the middle of switching the current user task or + * switching the loaded mm. It can also be dangerous if we + * interrupted some kernel code that was temporarily using a + * different mm. + */ +static inline bool nmi_uaccess_okay(void) +{ + struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm); + struct mm_struct *current_mm = current->mm; + + VM_WARN_ON_ONCE(!loaded_mm); + + /* + * The condition we want to check is + * current_mm->pgd == __va(read_cr3_pa()). This may be slow, though, + * if we're running in a VM with shadow paging, and nmi_uaccess_okay() + * is supposed to be reasonably fast. + * + * Instead, we check the almost equivalent but somewhat conservative + * condition below, and we rely on the fact that switch_mm_irqs_off() + * sets loaded_mm to LOADED_MM_SWITCHING before writing to CR3. + */ + if (loaded_mm != current_mm) + return false; + + VM_WARN_ON_ONCE(current_mm->pgd != __va(read_cr3_pa())); + + return true; +} + /* Initialize cr4 shadow for this CPU. */ static inline void cr4_init_shadow(void) { @@ -491,23 +531,30 @@ struct flush_tlb_info { unsigned long start; unsigned long end; u64 new_tlb_gen; + unsigned int stride_shift; + bool freed_tables; }; #define local_flush_tlb() __flush_tlb() -#define flush_tlb_mm(mm) flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL) +#define flush_tlb_mm(mm) \ + flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL, true) -#define flush_tlb_range(vma, start, end) \ - flush_tlb_mm_range(vma->vm_mm, start, end, vma->vm_flags) +#define flush_tlb_range(vma, start, end) \ + flush_tlb_mm_range((vma)->vm_mm, start, end, \ + ((vma)->vm_flags & VM_HUGETLB) \ + ? huge_page_shift(hstate_vma(vma)) \ + : PAGE_SHIFT, false) extern void flush_tlb_all(void); extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, - unsigned long end, unsigned long vmflag); + unsigned long end, unsigned int stride_shift, + bool freed_tables); extern void flush_tlb_kernel_range(unsigned long start, unsigned long end); static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a) { - flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, VM_NONE); + flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT, false); } void native_flush_tlb_others(const struct cpumask *cpumask, @@ -536,11 +583,9 @@ extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch); #ifndef CONFIG_PARAVIRT #define flush_tlb_others(mask, info) \ native_flush_tlb_others(mask, info) -#endif -extern void tlb_flush_remove_tables(struct mm_struct *mm); -extern void tlb_flush_remove_tables_local(void *arg); - -#define HAVE_TLB_FLUSH_REMOVE_TABLES +#define paravirt_tlb_remove_table(tlb, page) \ + tlb_remove_page(tlb, (void *)(page)) +#endif #endif /* _ASM_X86_TLBFLUSH_H */ |
