Merge branch 'msm-fixes-4.7-rc3' of git://people.freedesktop.org/~robclark/linux...

[karo-tx-linux.git] / arch / arm64 / mm / fault.c

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 95df28bc875f3eafda13f348e7f319fdafe5cd41..5954881a35ac516aed1bfb0844249feb551f40b3 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -81,6 +81,56 @@ void show_pte(struct mm_struct *mm, unsigned long addr)
        printk("\n");
 }
 
+#ifdef CONFIG_ARM64_HW_AFDBM
+/*
+ * This function sets the access flags (dirty, accessed), as well as write
+ * permission, and only to a more permissive setting.
+ *
+ * It needs to cope with hardware update of the accessed/dirty state by other
+ * agents in the system and can safely skip the __sync_icache_dcache() call as,
+ * like set_pte_at(), the PTE is never changed from no-exec to exec here.
+ *
+ * Returns whether or not the PTE actually changed.
+ */
+int ptep_set_access_flags(struct vm_area_struct *vma,
+                         unsigned long address, pte_t *ptep,
+                         pte_t entry, int dirty)
+{
+       pteval_t old_pteval;
+       unsigned int tmp;
+
+       if (pte_same(*ptep, entry))
+               return 0;
+
+       /* only preserve the access flags and write permission */
+       pte_val(entry) &= PTE_AF | PTE_WRITE | PTE_DIRTY;
+
+       /*
+        * PTE_RDONLY is cleared by default in the asm below, so set it in
+        * back if necessary (read-only or clean PTE).
+        */
+       if (!pte_write(entry) || !dirty)
+               pte_val(entry) |= PTE_RDONLY;
+
+       /*
+        * Setting the flags must be done atomically to avoid racing with the
+        * hardware update of the access/dirty state.
+        */
+       asm volatile("//        ptep_set_access_flags\n"
+       "       prfm    pstl1strm, %2\n"
+       "1:     ldxr    %0, %2\n"
+       "       and     %0, %0, %3              // clear PTE_RDONLY\n"
+       "       orr     %0, %0, %4              // set flags\n"
+       "       stxr    %w1, %0, %2\n"
+       "       cbnz    %w1, 1b\n"
+       : "=&r" (old_pteval), "=&r" (tmp), "+Q" (pte_val(*ptep))
+       : "L" (~PTE_RDONLY), "r" (pte_val(entry)));
+
+       flush_tlb_fix_spurious_fault(vma, address);
+       return 1;
+}
+#endif
+
 /*
  * The kernel tried to access some page that wasn't present.
  */
@@ -212,10 +262,6 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
        tsk = current;
        mm  = tsk->mm;
 
-       /* Enable interrupts if they were enabled in the parent context. */
-       if (interrupts_enabled(regs))
-               local_irq_enable();
-
        /*
         * If we're in an interrupt or have no user context, we must not take
         * the fault.
@@ -555,20 +601,33 @@ asmlinkage int __exception do_debug_exception(unsigned long addr,
 {
        const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
        struct siginfo info;
+       int rv;
 
-       if (!inf->fn(addr, esr, regs))
-               return 1;
+       /*
+        * Tell lockdep we disabled irqs in entry.S. Do nothing if they were
+        * already disabled to preserve the last enabled/disabled addresses.
+        */
+       if (interrupts_enabled(regs))
+               trace_hardirqs_off();
 
-       pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
-                inf->name, esr, addr);
+       if (!inf->fn(addr, esr, regs)) {
+               rv = 1;
+       } else {
+               pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
+                        inf->name, esr, addr);
+
+               info.si_signo = inf->sig;
+               info.si_errno = 0;
+               info.si_code  = inf->code;
+               info.si_addr  = (void __user *)addr;
+               arm64_notify_die("", regs, &info, 0);
+               rv = 0;
+       }
 
-       info.si_signo = inf->sig;
-       info.si_errno = 0;
-       info.si_code  = inf->code;
-       info.si_addr  = (void __user *)addr;
-       arm64_notify_die("", regs, &info, 0);
+       if (interrupts_enabled(regs))
+               trace_hardirqs_on();
 
-       return 0;
+       return rv;
 }
 
 #ifdef CONFIG_ARM64_PAN