powerpc: Disable interrupts for data breakpoint exceptions

Data address breakpoint exceptions are currently handled along with page-faults
which require interrupts to remain in enabled state. Since exception handling
for data breakpoints aren't pre-empt safe, we handle them separately.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 15 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index e3be98ffe2a7..3e423fbad6bc 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -735,8 +735,11 @@ _STATIC(do_hash_page)
         std     r3,_DAR(r1)
         std     r4,_DSISR(r1)
 
-        andis.  r0,r4,0xa450            /* weird error? */
+        andis.  r0,r4,0xa410            /* weird error? */
         bne-    handle_page_fault       /* if not, try to insert a HPTE */
+        andis.  r0,r4,DSISR_DABRMATCH@h
+        bne-    handle_dabr_fault
+
 BEGIN_FTR_SECTION
         andis.  r0,r4,0x0020            /* Is it a segment table fault? */
         bne-    do_ste_alloc            /* If so handle it */
@@ -823,6 +826,14 @@ END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)
         bl      .raw_local_irq_restore
         b       11f
 
+/* We have a data breakpoint exception - handle it */
+handle_dabr_fault:
+        ld      r4,_DAR(r1)
+        ld      r5,_DSISR(r1)
+        addi    r3,r1,STACK_FRAME_OVERHEAD
+        bl      .do_dabr
+        b       .ret_from_except_lite
+
 /* Here we have a page fault that hash_page can't handle. */
 handle_page_fault:
         ENABLE_INTS
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 26fb6b990b0a..83ac4935eb10 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -151,13 +151,14 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
         if (!user_mode(regs) && (address >= TASK_SIZE))
                 return SIGSEGV;
 
-#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
+#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE) || \
+                             defined(CONFIG_PPC_BOOK3S_64))
         if (error_code & DSISR_DABRMATCH) {
                 /* DABR match */
                 do_dabr(regs, address, error_code);
                 return 0;
         }
-#endif /* !(CONFIG_4xx || CONFIG_BOOKE)*/
+#endif
 
         if (in_atomic() || mm == NULL) {
                 if (!user_mode(regs))