powerpc/book3e: Add generic 64-bit idle powersave support

[mv-sheeva.git] / arch / powerpc / kernel / exceptions-64e.S

diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index a42637c3a72d9f7a25c69abaff956f9a0ff2edfd..316465a32a9c28b3020c569d416a49e76c869743 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -204,11 +204,30 @@ 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;
@@ -257,6 +276,7 @@ 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
@@ -268,6 +288,7 @@ 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       .
@@ -338,6 +359,7 @@ 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
@@ -434,6 +456,7 @@ kernel_dbg_exc:
        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