FAILED: patch "[PATCH] powerpc/64s: Fix system reset interrupt winkle wakeups" failed to apply to 4.4-stable tree

FAILED: patch "[PATCH] powerpc/64s: Fix system reset interrupt winkle wakeups" failed to apply to 4.4-stable tree

[gregkh]

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From f23ed166f283b1a6f0a1f0b0c889e8df9a10ff85 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Wed, 2 Nov 2016 17:57:01 +1100
Subject: [PATCH] powerpc/64s: Fix system reset interrupt winkle wakeups

Wakeups from winkle set the low bit of the HSPRG0 register, to
distinguish it from other sleep states. This is also the PACA pointer.
The system reset exception handler fails to mask this bit away before
using this value before using it as the PACA pointer.

Fix this by adding a new type of exception prolog macro where we already
have the PACA set in r13, and have the system reset vector mask it out.
The winkle wakeup handler will store the masked value back into HSPRG0.

Fixes: fb479e44a9e2 ("powerpc/64s: relocation, register save fixes for system reset interrupt")
Cc: stable@vger.kernel.org # v3.0+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 84d49b197c32..3ce43664eadf 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -158,14 +158,17 @@ BEGIN_FTR_SECTION_NESTED(943)						\
 	std	ra,offset(r13);						\
 END_FTR_SECTION_NESTED(ftr,ftr,943)
 
-#define EXCEPTION_PROLOG_0(area)					\
-	GET_PACA(r13);							\
+#define EXCEPTION_PROLOG_0_PACA(area)					\
 	std	r9,area+EX_R9(r13);	/* save r9 */			\
 	OPT_GET_SPR(r9, SPRN_PPR, CPU_FTR_HAS_PPR);			\
 	HMT_MEDIUM;							\
 	std	r10,area+EX_R10(r13);	/* save r10 - r12 */		\
 	OPT_GET_SPR(r10, SPRN_CFAR, CPU_FTR_CFAR)
 
+#define EXCEPTION_PROLOG_0(area)					\
+	GET_PACA(r13);							\
+	EXCEPTION_PROLOG_0_PACA(area)
+
 #define __EXCEPTION_PROLOG_1(area, extra, vec)				\
 	OPT_SAVE_REG_TO_PACA(area+EX_PPR, r9, CPU_FTR_HAS_PPR);		\
 	OPT_SAVE_REG_TO_PACA(area+EX_CFAR, r10, CPU_FTR_CFAR);		\
@@ -196,6 +199,12 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 	EXCEPTION_PROLOG_1(area, extra, vec);				\
 	EXCEPTION_PROLOG_PSERIES_1(label, h);
 
+/* Have the PACA in r13 already */
+#define EXCEPTION_PROLOG_PSERIES_PACA(area, label, h, extra, vec)	\
+	EXCEPTION_PROLOG_0_PACA(area);					\
+	EXCEPTION_PROLOG_1(area, extra, vec);				\
+	EXCEPTION_PROLOG_PSERIES_1(label, h);
+
 #define __KVMTEST(h, n)							\
 	lbz	r10,HSTATE_IN_GUEST(r13);				\
 	cmpwi	r10,0;							\
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 08ba447a4b3d..1ba82ea90230 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -116,7 +116,9 @@ EXC_VIRT_NONE(0x4000, 0x4100)
 
 EXC_REAL_BEGIN(system_reset, 0x100, 0x200)
 	SET_SCRATCH0(r13)
-	EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common, EXC_STD,
+	GET_PACA(r13)
+	clrrdi	r13,r13,1 /* Last bit of HSPRG0 is set if waking from winkle */
+	EXCEPTION_PROLOG_PSERIES_PACA(PACA_EXGEN, system_reset_common, EXC_STD,
 				 IDLETEST, 0x100)
 
 EXC_REAL_END(system_reset, 0x100, 0x200)
@@ -124,6 +126,9 @@ EXC_VIRT_NONE(0x4100, 0x4200)
 
 #ifdef CONFIG_PPC_P7_NAP
 EXC_COMMON_BEGIN(system_reset_idle_common)
+BEGIN_FTR_SECTION
+	GET_PACA(r13) /* Restore HSPRG0 to get the winkle bit in r13 */
+END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
 	bl	pnv_restore_hyp_resource
 
 	li	r0,PNV_THREAD_RUNNING
@@ -169,7 +174,7 @@ EXC_REAL_BEGIN(machine_check, 0x200, 0x300)
 	SET_SCRATCH0(r13)		/* save r13 */
 	/*
 	 * Running native on arch 2.06 or later, we may wakeup from winkle
-	 * inside machine check. If yes, then last bit of HSPGR0 would be set
+	 * inside machine check. If yes, then last bit of HSPRG0 would be set
 	 * to 1. Hence clear it unconditionally.
 	 */
 	GET_PACA(r13)
@@ -388,7 +393,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
 	/*
 	 * Go back to winkle. Please note that this thread was woken up in
 	 * machine check from winkle and have not restored the per-subcore
-	 * state. Hence before going back to winkle, set last bit of HSPGR0
+	 * state. Hence before going back to winkle, set last bit of HSPRG0
 	 * to 1. This will make sure that if this thread gets woken up
 	 * again at reset vector 0x100 then it will get chance to restore
 	 * the subcore state.