mm/arm64: use general page fault accounting

Use the general page fault accounting by passing regs into
handle_mm_fault().  It naturally solve the issue of multiple page fault
accounting when page fault retry happened.  To do this, we pass pt_regs
pointer into __do_page_fault().

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-6-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index be29f4076fe3c2b4c4622373361622a2977030f7..f07333e86c2ff927994148ab19532c397100fc7a 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -404,7 +404,8 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re
 #define VM_FAULT_BADACCESS     0x020000
 
 static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,
-                          unsigned int mm_flags, unsigned long vm_flags)
+                                 unsigned int mm_flags, unsigned long vm_flags,
+                                 struct pt_regs *regs)
 {
        struct vm_area_struct *vma = find_vma(mm, addr);
 
@@ -428,7 +429,7 @@ static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,
         */
        if (!(vma->vm_flags & vm_flags))
                return VM_FAULT_BADACCESS;
-       return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, NULL);
+       return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, regs);
 }
 
 static bool is_el0_instruction_abort(unsigned int esr)
@@ -450,7 +451,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 {
        const struct fault_info *inf;
        struct mm_struct *mm = current->mm;
-       vm_fault_t fault, major = 0;
+       vm_fault_t fault;
        unsigned long vm_flags = VM_ACCESS_FLAGS;
        unsigned int mm_flags = FAULT_FLAG_DEFAULT;
 
@@ -516,8 +517,7 @@ retry:
 #endif
        }
 
-       fault = __do_page_fault(mm, addr, mm_flags, vm_flags);
-       major |= fault & VM_FAULT_MAJOR;
+       fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs);
 
        /* Quick path to respond to signals */
        if (fault_signal_pending(fault, regs)) {
@@ -538,25 +538,8 @@ retry:
         * Handle the "normal" (no error) case first.
         */
        if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
-                             VM_FAULT_BADACCESS)))) {
-               /*
-                * Major/minor page fault accounting is only done
-                * once. If we go through a retry, it is extremely
-                * likely that the page will be found in page cache at
-                * that point.
-                */
-               if (major) {
-                       current->maj_flt++;
-                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
-                                     addr);
-               } else {
-                       current->min_flt++;
-                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
-                                     addr);
-               }
-
+                             VM_FAULT_BADACCESS))))
                return 0;
-       }
 
        /*
         * If we are in kernel mode at this point, we have no context to