arm: mm: drop VM_FAULT_BADMAP/VM_FAULT_BADACCESS

If bad map or access, directly set code to SEGV_MAPRR or SEGV_ACCERR, also
set fault to 0 and goto error handling, which make us to drop the arch's
special vm fault reason.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kefeng Wang <[email protected]>
Cc: Aishwarya TCV <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Cristian Marussi <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

arch/arm/mm/fault.c

@@ -226,9 +226,6 @@ void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 }
 
 #ifdef CONFIG_MMU
-#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000)
-#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000)
-
 static inline bool is_permission_fault(unsigned int fsr)
 {
  int fs = fsr_fs(fsr);
@@ -295,7 +292,8 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
  if (!(vma->vm_flags & vm_flags)) {
  vma_end_read(vma);
  count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
- fault = VM_FAULT_BADACCESS;
+ fault = 0;
+ code = SEGV_ACCERR;
  goto bad_area;
  }
  fault = handle_mm_fault(vma, addr, flags | FAULT_FLAG_VMA_LOCK, regs);
@@ -321,18 +319,23 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 retry:
  vma = lock_mm_and_find_vma(mm, addr, regs);
  if (unlikely(!vma)) {
- fault = VM_FAULT_BADMAP;
+ fault = 0;
+ code = SEGV_MAPERR;
  goto bad_area;
  }
 
  /*
  * ok, we have a good vm_area for this memory access, check the
  * permissions on the VMA allow for the fault which occurred.
  */
- if (!(vma->vm_flags & vm_flags))
- fault = VM_FAULT_BADACCESS;
- else
- fault = handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
+ if (!(vma->vm_flags & vm_flags)) {
+ mmap_read_unlock(mm);
+ fault = 0;
+ code = SEGV_ACCERR;
+ goto bad_area;
+ }
+
+ fault = handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
 
  /* If we need to retry but a fatal signal is pending, handle the
  * signal first. We do not need to release the mmap_lock because
@@ -358,12 +361,11 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
  mmap_read_unlock(mm);
 done:
 
- /*
- * Handle the "normal" case first - VM_FAULT_MAJOR
- */
- if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
+ /* Handle the "normal" case first */
+ if (likely(!(fault & VM_FAULT_ERROR)))
  return 0;
 
+ code = SEGV_MAPERR;
 bad_area:
  /*
  * If we are in kernel mode at this point, we
@@ -395,8 +397,6 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
  * isn't in our memory map..
  */
  sig = SIGSEGV;
- code = fault == VM_FAULT_BADACCESS ?
- SEGV_ACCERR : SEGV_MAPERR;
  }
 
  __do_user_fault(addr, fsr, sig, code, regs);