diff options
Diffstat (limited to 'arch/x86/include/asm/mmu_context.h')
-rw-r--r-- | arch/x86/include/asm/mmu_context.h | 55 |
1 files changed, 52 insertions, 3 deletions
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 166af2a8e865..4b75d591eb5e 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -10,9 +10,8 @@ #include <asm/pgalloc.h> #include <asm/tlbflush.h> #include <asm/paravirt.h> +#include <asm/mpx.h> #ifndef CONFIG_PARAVIRT -#include <asm-generic/mm_hooks.h> - static inline void paravirt_activate_mm(struct mm_struct *prev, struct mm_struct *next) { @@ -53,7 +52,16 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, /* Stop flush ipis for the previous mm */ cpumask_clear_cpu(cpu, mm_cpumask(prev)); - /* Load the LDT, if the LDT is different: */ + /* + * Load the LDT, if the LDT is different. + * + * It's possible leave_mm(prev) has been called. If so, + * then prev->context.ldt could be out of sync with the + * LDT descriptor or the LDT register. This can only happen + * if prev->context.ldt is non-null, since we never free + * an LDT. But LDTs can't be shared across mms, so + * prev->context.ldt won't be equal to next->context.ldt. + */ if (unlikely(prev->context.ldt != next->context.ldt)) load_LDT_nolock(&next->context); } @@ -102,4 +110,45 @@ do { \ } while (0) #endif +static inline void arch_dup_mmap(struct mm_struct *oldmm, + struct mm_struct *mm) +{ + paravirt_arch_dup_mmap(oldmm, mm); +} + +static inline void arch_exit_mmap(struct mm_struct *mm) +{ + paravirt_arch_exit_mmap(mm); +} + +static inline void arch_bprm_mm_init(struct mm_struct *mm, + struct vm_area_struct *vma) +{ + mpx_mm_init(mm); +} + +static inline void arch_unmap(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + /* + * mpx_notify_unmap() goes and reads a rarely-hot + * cacheline in the mm_struct. That can be expensive + * enough to be seen in profiles. + * + * The mpx_notify_unmap() call and its contents have been + * observed to affect munmap() performance on hardware + * where MPX is not present. + * + * The unlikely() optimizes for the fast case: no MPX + * in the CPU, or no MPX use in the process. Even if + * we get this wrong (in the unlikely event that MPX + * is widely enabled on some system) the overhead of + * MPX itself (reading bounds tables) is expected to + * overwhelm the overhead of getting this unlikely() + * consistently wrong. + */ + if (unlikely(cpu_feature_enabled(X86_FEATURE_MPX))) + mpx_notify_unmap(mm, vma, start, end); +} + #endif /* _ASM_X86_MMU_CONTEXT_H */ |