powerpc/booke64: Use GSRR registers in Guest Doorbell interrupts

Guest Doorbell interrupts use guest save and restore registers. Add a new
Guest Doorbell exception type to accommodate GSRR0/1 SPRs usage in exception
prolog and fix the exception handler.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/exception-64e.h b/arch/powerpc/include/asm/exception-64e.h
index ac13add..e73452f 100644 (file)
--- a/arch/powerpc/include/asm/exception-64e.h
+++ b/arch/powerpc/include/asm/exception-64e.h
@@ -37,6 +37,7 @@
  * critical data
  */
 
+#define PACA_EXGDBELL PACA_EXGEN
 
 /* We are out of SPRGs so we save some things in the PACA. The normal
  * exception frame is smaller than the CRIT or MC one though

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 43bb15f..c195bf0 100644 (file)
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -863,6 +863,7 @@
 #define SPRN_SPRG_TLB_EXFRAME  SPRN_SPRG2
 #define SPRN_SPRG_TLB_SCRATCH  SPRN_SPRG6
 #define SPRN_SPRG_GEN_SCRATCH  SPRN_SPRG0
+#define SPRN_SPRG_GDBELL_SCRATCH SPRN_SPRG_GEN_SCRATCH
 
 #define SET_PACA(rX)   mtspr   SPRN_SPRG_PACA,rX
 #define GET_PACA(rX)   mfspr   rX,SPRN_SPRG_PACA

diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 0243b1b..0f58a95 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -59,6 +59,10 @@
 #define SPRN_GEN_SRR0  SPRN_SRR0
 #define SPRN_GEN_SRR1  SPRN_SRR1
 
+#define        GDBELL_SET_KSTACK       GEN_SET_KSTACK
+#define SPRN_GDBELL_SRR0       SPRN_GSRR0
+#define SPRN_GDBELL_SRR1       SPRN_GSRR1
+
 #define CRIT_SET_KSTACK                                                            \
        ld      r1,PACA_CRIT_STACK(r13);                                    \
        subi    r1,r1,SPECIAL_EXC_FRAME_SIZE;
@@ -89,10 +93,13 @@
 #define MC_EXCEPTION_PROLOG(n, addition)                                   \
        EXCEPTION_PROLOG(n, MC, addition##_MC(n))
 
+#define GDBELL_EXCEPTION_PROLOG(n, addition)                               \
+       EXCEPTION_PROLOG(n, GDBELL, addition##_GDBELL(n))
 
 /* Variants of the "addition" argument for the prolog
  */
 #define PROLOG_ADDITION_NONE_GEN(n)
+#define PROLOG_ADDITION_NONE_GDBELL(n)
 #define PROLOG_ADDITION_NONE_CRIT(n)
 #define PROLOG_ADDITION_NONE_DBG(n)
 #define PROLOG_ADDITION_NONE_MC(n)
@@ -543,8 +550,18 @@ kernel_dbg_exc:
 //     b       ret_from_crit_except
        b       .
 
-/* Guest Doorbell */
-       MASKABLE_EXCEPTION(0x2c0, guest_doorbell, .unknown_exception, ACK_NONE)
+/*
+ *     Guest doorbell interrupt
+ *     This general exception use GSRRx save/restore registers
+ */
+       START_EXCEPTION(guest_doorbell);
+       GDBELL_EXCEPTION_PROLOG(0x2c0, PROLOG_ADDITION_NONE)
+       EXCEPTION_COMMON(0x2c0, PACA_EXGEN, INTS_KEEP)
+       addi    r3,r1,STACK_FRAME_OVERHEAD
+       bl      .save_nvgprs
+       INTS_RESTORE_HARD
+       bl      .unknown_exception
+       b       .ret_from_except
 
 /* Guest Doorbell critical Interrupt */
        START_EXCEPTION(guest_doorbell_crit);