Messages in this thread Patch in this message | | | Date | Thu, 18 Feb 2016 12:21:30 -0800 | From | tip-bot for Dave Hansen <> | Subject | [tip:mm/pkeys] mm/gup: Factor out VMA fault permission checking |
| |
Commit-ID: d4925e00d59698a201231cf99dce47d8b922bb34 Gitweb: http://git.kernel.org/tip/d4925e00d59698a201231cf99dce47d8b922bb34 Author: Dave Hansen <dave.hansen@linux.intel.com> AuthorDate: Fri, 12 Feb 2016 13:02:16 -0800 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Thu, 18 Feb 2016 09:32:43 +0100
mm/gup: Factor out VMA fault permission checking
This code matches a fault condition up with the VMA and ensures that the VMA allows the fault to be handled instead of just erroring out.
We will be extending this in a moment to comprehend protection keys.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dominik Dingel <dingel@linux.vnet.ibm.com> Cc: Eric B Munson <emunson@akamai.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jason Low <jason.low2@hp.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210216.C3824032@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- mm/gup.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c index de24ef4..b935c2c 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -610,6 +610,18 @@ next_page: } EXPORT_SYMBOL(__get_user_pages); +bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags) +{ + vm_flags_t vm_flags; + + vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ; + + if (!(vm_flags & vma->vm_flags)) + return false; + + return true; +} + /* * fixup_user_fault() - manually resolve a user page fault * @tsk: the task_struct to use for page fault accounting, or @@ -645,7 +657,6 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, bool *unlocked) { struct vm_area_struct *vma; - vm_flags_t vm_flags; int ret, major = 0; if (unlocked) @@ -656,8 +667,7 @@ retry: if (!vma || address < vma->vm_start) return -EFAULT; - vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ; - if (!(vm_flags & vma->vm_flags)) + if (!vma_permits_fault(vma, fault_flags)) return -EFAULT; ret = handle_mm_fault(mm, vma, address, fault_flags);
| |