Subject: [PATCH 3/4] powerpc/64s: Prepare to handle data interrupts vs d-side MCE reentrancy

From: Nicholas Piggin <[email-masked]>
Date: Tue, 22 Jan 2019 16:46:17 +1000

The subsequent patch needs to change data interrupts (those that set
DAR / DSISR) in order to cope with a recoverability bug with MCE
interrupts.

This patch prepares for the fix by removing a couple of layers of
macro indirection from the interrupt handlers, and also makes the
0x300 interrupt out of line (as required by the next patch).

Functionality should be unchanged, and code unchanged except for the
OOL change.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/exceptions-64s.S | 45 ++++++++++++++++++++++++----
 1 file changed, 39 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 9e253ce27e08..0d91d1c8aad1 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -566,8 +566,23 @@ EXC_COMMON_BEGIN(mce_return)
 	RFI_TO_KERNEL
 	b	.
 
-EXC_REAL(data_access, 0x300, 0x80)
-EXC_VIRT(data_access, 0x4300, 0x80, 0x300)
+EXC_REAL_BEGIN(data_access, 0x300, 0x80)
+SET_SCRATCH0(r13)		/* save r13 */
+EXCEPTION_PROLOG_0(PACA_EXGEN)
+	b	tramp_real_data_access
+EXC_REAL_END(data_access, 0x300, 0x80)
+
+TRAMP_REAL_BEGIN(tramp_real_data_access)
+EXCEPTION_PROLOG_1(PACA_EXGEN, KVMTEST_PR, 0x300)
+EXCEPTION_PROLOG_2(data_access_common, EXC_STD)
+
+EXC_VIRT_BEGIN(data_access, 0x4300, 0x80)
+SET_SCRATCH0(r13)		/* save r13 */
+EXCEPTION_PROLOG_0(PACA_EXGEN)
+EXCEPTION_PROLOG_1(PACA_EXGEN, NOTEST, 0x300)
+EXCEPTION_PROLOG_2_RELON(data_access_common, EXC_STD)
+EXC_VIRT_END(data_access, 0x4300, 0x80)
+
 TRAMP_KVM_SKIP(PACA_EXGEN, 0x300)
 
 EXC_COMMON_BEGIN(data_access_common)
@@ -596,11 +611,17 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)

 EXC_REAL_BEGIN(data_access_slb, 0x380, 0x80)
-EXCEPTION_PROLOG(PACA_EXSLB, data_access_slb_common, EXC_STD, KVMTEST_PR, 0x380);
+SET_SCRATCH0(r13)		/* save r13 */
+EXCEPTION_PROLOG_0(PACA_EXSLB)
+EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST_PR, 0x380)
+EXCEPTION_PROLOG_2(data_access_slb_common, EXC_STD)
 EXC_REAL_END(data_access_slb, 0x380, 0x80)
 
 EXC_VIRT_BEGIN(data_access_slb, 0x4380, 0x80)
-EXCEPTION_RELON_PROLOG(PACA_EXSLB, data_access_slb_common, EXC_STD, NOTEST, 0x380);
+SET_SCRATCH0(r13)		/* save r13 */
+EXCEPTION_PROLOG_0(PACA_EXSLB)
+EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x380)
+EXCEPTION_PROLOG_2_RELON(data_access_slb_common, EXC_STD)
 EXC_VIRT_END(data_access_slb, 0x4380, 0x80)
 
 TRAMP_KVM_SKIP(PACA_EXSLB, 0x380)
@@ -703,8 +724,20 @@ TRAMP_KVM_HV(PACA_EXGEN, 0x500)
 EXC_COMMON_ASYNC(hardware_interrupt_common, 0x500, do_IRQ)

-EXC_REAL(alignment, 0x600, 0x100)
-EXC_VIRT(alignment, 0x4600, 0x100, 0x600)
+EXC_REAL_BEGIN(alignment, 0x600, 0x100)
+SET_SCRATCH0(r13)		/* save r13 */
+EXCEPTION_PROLOG_0(PACA_EXGEN)
+EXCEPTION_PROLOG_1(PACA_EXGEN, KVMTEST_PR, 0x600)
+EXCEPTION_PROLOG_2(alignment_common, EXC_STD)
+EXC_REAL_END(alignment, 0x600, 0x100)
+
+EXC_VIRT_BEGIN(alignment, 0x4600, 0x100)
+SET_SCRATCH0(r13)		/* save r13 */
+EXCEPTION_PROLOG_0(PACA_EXGEN)
+EXCEPTION_PROLOG_1(PACA_EXGEN, NOTEST, 0x600)
+EXCEPTION_PROLOG_2_RELON(alignment_common, EXC_STD)
+EXC_VIRT_END(alignment, 0x4600, 0x100)
+
 TRAMP_KVM(PACA_EXGEN, 0x600)
 EXC_COMMON_BEGIN(alignment_common)
 	mfspr	r10,SPRN_DAR
-- 
2.18.0