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From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 28/28] powerpc/64s/exception: avoid SPR RAW scoreboard stall in real mode entry
Date: Wed, 12 Jun 2019 00:30:40 +1000	[thread overview]
Message-ID: <20190611143040.7834-29-npiggin@gmail.com> (raw)
In-Reply-To: <20190611143040.7834-1-npiggin@gmail.com>

Move SPR reads ahead of writes. Real mode entry that is not a KVM
guest is rare these days, but bad practice propagates.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kernel/exceptions-64s.S | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index d9e531a00319..df9c3126fe08 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -183,19 +183,19 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 	.endif
 	.if \hsrr
 	mfspr	r11,SPRN_HSRR0		/* save HSRR0 */
+	mfspr	r12,SPRN_HSRR1		/* and HSRR1 */
+	mtspr	SPRN_HSRR1,r10
 	.else
 	mfspr	r11,SPRN_SRR0		/* save SRR0 */
+	mfspr	r12,SPRN_SRR1		/* and SRR1 */
+	mtspr	SPRN_SRR1,r10
 	.endif
-	LOAD_HANDLER(r12, \label\())
+	LOAD_HANDLER(r10, \label\())
 	.if \hsrr
-	mtspr	SPRN_HSRR0,r12
-	mfspr	r12,SPRN_HSRR1		/* and HSRR1 */
-	mtspr	SPRN_HSRR1,r10
+	mtspr	SPRN_HSRR0,r10
 	HRFI_TO_KERNEL
 	.else
-	mtspr	SPRN_SRR0,r12
-	mfspr	r12,SPRN_SRR1		/* and SRR1 */
-	mtspr	SPRN_SRR1,r10
+	mtspr	SPRN_SRR0,r10
 	RFI_TO_KERNEL
 	.endif
 	b	.	/* prevent speculative execution */
-- 
2.20.1


      parent reply	other threads:[~2019-06-11 15:52 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-11 14:30 [PATCH 00/28] powerpc/64s interrupt handler cleanups, gasification Nicholas Piggin
2019-06-11 14:30 ` [PATCH 01/28] powerpc/64s/exception: fix line wrap and semicolon inconsistencies in macros Nicholas Piggin
2019-07-04 15:52   ` Michael Ellerman
2019-06-11 14:30 ` [PATCH 02/28] powerpc/64s/exception: remove H concatenation for EXC_HV variants Nicholas Piggin
2019-06-11 14:30 ` [PATCH 03/28] powerpc/64s/exception: consolidate EXCEPTION_PROLOG_2 with _NORI variant Nicholas Piggin
2019-06-11 14:30 ` [PATCH 04/28] powerpc/64s/exception: move and tidy EXCEPTION_PROLOG_2 variants Nicholas Piggin
2019-06-11 14:30 ` [PATCH 05/28] powerpc/64s/exception: fix sreset KVM test code Nicholas Piggin
2019-06-11 14:30 ` [PATCH 06/28] powerpc/64s/exception: remove the "extra" macro parameter Nicholas Piggin
2019-06-19  8:40   ` Nicholas Piggin
2019-06-19 10:02     ` Michael Ellerman
2019-06-11 14:30 ` [PATCH 07/28] powerpc/64s/exception: consolidate maskable and non-maskable prologs Nicholas Piggin
2019-06-11 14:30 ` [PATCH 08/28] powerpc/64s/exception: merge KVM handler and skip variants Nicholas Piggin
2019-06-11 14:30 ` [PATCH 09/28] powerpc/64s/exception: KVM handler can set the HSRR trap bit Nicholas Piggin
2019-06-11 14:30 ` [PATCH 10/28] powerpc/64s/exception: Make EXCEPTION_PROLOG_0 a gas macro for consistency with others Nicholas Piggin
2019-06-11 14:30 ` [PATCH 11/28] powerpc/64s/exception: Move EXCEPTION_COMMON handler and return branches into callers Nicholas Piggin
2019-06-11 14:30 ` [PATCH 12/28] powerpc/64s/exception: Move EXCEPTION_COMMON additions " Nicholas Piggin
2019-06-11 14:30 ` [PATCH 13/28] powerpc/64s/exception: unwind exception-64s.h macros Nicholas Piggin
2019-06-11 14:30 ` [PATCH 14/28] powerpc/64s/exception: improve 0x500 handler code Nicholas Piggin
2019-06-11 14:30 ` [PATCH 15/28] powerpc/64s/exception: move EXCEPTION_PROLOG_2* to a more logical place Nicholas Piggin
2019-06-11 14:30 ` [PATCH 16/28] powerpc/64s/exception: remove STD_EXCEPTION_COMMON variants Nicholas Piggin
2019-06-11 14:30 ` [PATCH 17/28] powerpc/64s/exception: move KVM related code together Nicholas Piggin
2019-06-11 14:30 ` [PATCH 18/28] powerpc/64s/exception: move exception-64s.h code to exception-64s.S where it is used Nicholas Piggin
2019-06-11 14:30 ` [PATCH 19/28] powerpc/64s/exception: move head-64.h " Nicholas Piggin
2019-06-11 14:30 ` [PATCH 20/28] powerpc/64s/exception: remove __BRANCH_TO_KVM Nicholas Piggin
2019-06-11 14:30 ` [PATCH 21/28] powerpc/64s/exception: use a gas macro for system call handler code Nicholas Piggin
2019-06-11 14:30 ` [PATCH 22/28] powerpc/64s/exception: fix indenting irregularities Nicholas Piggin
2019-06-11 14:30 ` [PATCH 23/28] powerpc/64s/exception: generate regs clear instructions using .rept Nicholas Piggin
2019-06-11 14:30 ` [PATCH 24/28] powerpc/64s/exception: remove bad stack branch Nicholas Piggin
2019-06-11 14:30 ` [PATCH 25/28] powerpc/64s/exception: remove pointless EXCEPTION_PROLOG macro indirection Nicholas Piggin
2019-06-11 14:30 ` [PATCH 26/28] powerpc/64s/exception: move paca save area offsets into exception-64s.S Nicholas Piggin
2019-06-11 14:30 ` [PATCH 27/28] powerpc/64s/exception: clean up system call entry Nicholas Piggin
2019-06-11 14:30 ` Nicholas Piggin [this message]

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