1 files changed, 46 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 24dcc0ecf24..5c43063d250 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -191,6 +191,12 @@ exc_##n##_bad_stack:							    \
         sth     r1,PACA_TRAP_SAVE(r13); /* store trap */                    \
         b       bad_stack_book3e;       /* bad stack error */
 
+/* WARNING: If you change the layout of this stub, make sure you chcek
+        *   the debug exception handler which handles single stepping
+        *   into exceptions from userspace, and the MM code in
+        *   arch/powerpc/mm/tlb_nohash.c which patches the branch here
+        *   and would need to be updated if that branch is moved
+        */
 #define EXCEPTION_STUB(loc, label)                                      \
         . = interrupt_base_book3e + loc;                                \
         nop;    /* To make debug interrupts happy */                    \
@@ -204,11 +210,30 @@ exc_##n##_bad_stack:							    \
         lis     r,TSR_FIS@h;                                            \
         mtspr   SPRN_TSR,r
 
+/* Used by asynchronous interrupt that may happen in the idle loop.
+ *
+ * This check if the thread was in the idle loop, and if yes, returns
+ * to the caller rather than the PC. This is to avoid a race if
+ * interrupts happen before the wait instruction.
+ */
+#define CHECK_NAPPING()                                                 \
+        clrrdi  r11,r1,THREAD_SHIFT;                                    \
+        ld      r10,TI_LOCAL_FLAGS(r11);                                \
+        andi.   r9,r10,_TLF_NAPPING;                                    \
+        beq+    1f;                                                     \
+        ld      r8,_LINK(r1);                                           \
+        rlwinm  r7,r10,0,~_TLF_NAPPING;                                 \
+        std     r8,_NIP(r1);                                            \
+        std     r7,TI_LOCAL_FLAGS(r11);                                 \
+1:
+
+
 #define MASKABLE_EXCEPTION(trapnum, label, hdlr, ack)                   \
         START_EXCEPTION(label);                                         \
         NORMAL_EXCEPTION_PROLOG(trapnum, PROLOG_ADDITION_MASKABLE)      \
         EXCEPTION_COMMON(trapnum, PACA_EXGEN, INTS_DISABLE_ALL)         \
         ack(r8);                                                        \
+        CHECK_NAPPING();                                                \
         addi    r3,r1,STACK_FRAME_OVERHEAD;                             \
         bl      hdlr;                                                   \
         b       .ret_from_except_lite;
@@ -246,11 +271,9 @@ interrupt_base_book3e:					/* fake trap */
         EXCEPTION_STUB(0x1a0, watchdog)                 /* 0x09f0 */
         EXCEPTION_STUB(0x1c0, data_tlb_miss)
         EXCEPTION_STUB(0x1e0, instruction_tlb_miss)
+        EXCEPTION_STUB(0x280, doorbell)
+        EXCEPTION_STUB(0x2a0, doorbell_crit)
 
-#if 0
-        EXCEPTION_STUB(0x280, processor_doorbell)
-        EXCEPTION_STUB(0x220, processor_doorbell_crit)
-#endif
         .globl interrupt_end_book3e
 interrupt_end_book3e:
 
@@ -259,6 +282,7 @@ interrupt_end_book3e:
         CRIT_EXCEPTION_PROLOG(0x100, PROLOG_ADDITION_NONE)
 //      EXCEPTION_COMMON(0x100, PACA_EXCRIT, INTS_DISABLE_ALL)
 //      bl      special_reg_save_crit
+//      CHECK_NAPPING();
 //      addi    r3,r1,STACK_FRAME_OVERHEAD
 //      bl      .critical_exception
 //      b       ret_from_crit_except
@@ -270,6 +294,7 @@ interrupt_end_book3e:
 //      EXCEPTION_COMMON(0x200, PACA_EXMC, INTS_DISABLE_ALL)
 //      bl      special_reg_save_mc
 //      addi    r3,r1,STACK_FRAME_OVERHEAD
+//      CHECK_NAPPING();
 //      bl      .machine_check_exception
 //      b       ret_from_mc_except
         b       .
@@ -340,6 +365,7 @@ interrupt_end_book3e:
         CRIT_EXCEPTION_PROLOG(0x9f0, PROLOG_ADDITION_NONE)
 //      EXCEPTION_COMMON(0x9f0, PACA_EXCRIT, INTS_DISABLE_ALL)
 //      bl      special_reg_save_crit
+//      CHECK_NAPPING();
 //      addi    r3,r1,STACK_FRAME_OVERHEAD
 //      bl      .unknown_exception
 //      b       ret_from_crit_except
@@ -428,6 +454,20 @@ interrupt_end_book3e:
 kernel_dbg_exc:
         b       .       /* NYI */
 
+/* Doorbell interrupt */
+        MASKABLE_EXCEPTION(0x2070, doorbell, .doorbell_exception, ACK_NONE)
+
+/* Doorbell critical Interrupt */
+        START_EXCEPTION(doorbell_crit);
+        CRIT_EXCEPTION_PROLOG(0x2080, PROLOG_ADDITION_NONE)
+//      EXCEPTION_COMMON(0x2080, PACA_EXCRIT, INTS_DISABLE_ALL)
+//      bl      special_reg_save_crit
+//      CHECK_NAPPING();
+//      addi    r3,r1,STACK_FRAME_OVERHEAD
+//      bl      .doorbell_critical_exception
+//      b       ret_from_crit_except
+        b       .
+
 
 /*
  * An interrupt came in while soft-disabled; clear EE in SRR1,
@@ -563,6 +603,8 @@ BAD_STACK_TRAMPOLINE(0xd00)
 BAD_STACK_TRAMPOLINE(0xe00)
 BAD_STACK_TRAMPOLINE(0xf00)
 BAD_STACK_TRAMPOLINE(0xf20)
+BAD_STACK_TRAMPOLINE(0x2070)
+BAD_STACK_TRAMPOLINE(0x2080)
 
         .globl  bad_stack_book3e
 bad_stack_book3e: