4.9-stable review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski luto@kernel.org
commit ca6c99c0794875c6d1db6e22f246699691ab7e6b upstream.
flush_tlb_page() was very similar to flush_tlb_mm_range() except that it had a couple of issues:
- It was missing an smp_mb() in the case where current->active_mm != mm. (This is a longstanding bug reported by Nadav Amit)
- It was missing tracepoints and vm counter updates.
The only reason that I can see for keeping it at as a separate function is that it could avoid a few branches that flush_tlb_mm_range() needs to decide to flush just one page. This hardly seems worthwhile. If we decide we want to get rid of those branches again, a better way would be to introduce an __flush_tlb_mm_range() helper and make both flush_tlb_page() and flush_tlb_mm_range() use it.
Signed-off-by: Andy Lutomirski luto@kernel.org Acked-by: Kees Cook keescook@chromium.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Borislav Petkov bpetkov@suse.de Cc: Dave Hansen dave.hansen@intel.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Mel Gorman mgorman@suse.de Cc: Michal Hocko mhocko@suse.com Cc: Nadav Amit nadav.amit@gmail.com Cc: Nadav Amit namit@vmware.com Cc: Peter Zijlstra peterz@infradead.org Cc: Rik van Riel riel@redhat.com Cc: Thomas Gleixner tglx@linutronix.de Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/3cc3847cf888d8907577569b8bac3f01992ef8f9.1495492063... Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Hugh Dickins hughd@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/include/asm/tlbflush.h | 6 +++++- arch/x86/mm/tlb.c | 27 --------------------------- 2 files changed, 5 insertions(+), 28 deletions(-)
--- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -297,11 +297,15 @@ static inline void flush_tlb_kernel_rang flush_tlb_mm_range(vma->vm_mm, start, end, vma->vm_flags)
extern void flush_tlb_all(void); -extern void flush_tlb_page(struct vm_area_struct *, unsigned long); extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, unsigned long end, unsigned long vmflag); 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); +} + void native_flush_tlb_others(const struct cpumask *cpumask, struct mm_struct *mm, unsigned long start, unsigned long end); --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -354,33 +354,6 @@ out: preempt_enable(); }
-void flush_tlb_page(struct vm_area_struct *vma, unsigned long start) -{ - struct mm_struct *mm = vma->vm_mm; - - preempt_disable(); - - if (current->active_mm == mm) { - if (current->mm) { - /* - * Implicit full barrier (INVLPG) that synchronizes - * with switch_mm. - */ - __flush_tlb_one(start); - } else { - leave_mm(smp_processor_id()); - - /* Synchronize with switch_mm. */ - smp_mb(); - } - } - - if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids) - flush_tlb_others(mm_cpumask(mm), mm, start, start + PAGE_SIZE); - - preempt_enable(); -} - static void do_flush_tlb_all(void *info) { count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);