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From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 8/9] powerpc/64s: paca EX_R3 can be merged with EX_DAR
Date: Sun, 21 May 2017 23:15:49 +1000	[thread overview]
Message-ID: <20170521131550.25813-9-npiggin@gmail.com> (raw)
In-Reply-To: <20170521131550.25813-1-npiggin@gmail.com>

EX_R3 is used only for a small section of the bad stack handler.
Merge it with EX_DAR.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/include/asm/exception-64s.h | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index ba03db14e1e8..aaee57f0e5ad 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -34,12 +34,11 @@
 #define EX_DAR		40
 #define EX_DSISR	48
 #define EX_CCR		52
-#define EX_R3		56
-#define EX_CFAR		64
-#define EX_PPR		72
-#define EX_CTR		80
+#define EX_CFAR		56
+#define EX_PPR		64
+#define EX_CTR		72
 
-#define EX_SIZE		11	/* size in u64 units */
+#define EX_SIZE		10	/* size in u64 units */
 
 /*
  * EX_LR is only used in EXSLB and where it does not overlap with EX_DAR
@@ -49,6 +48,13 @@
  */
 #define EX_LR		EX_DAR
 
+/*
+ * EX_R3 is only used by the bad_stack handler. bad_stack reloads and
+ * saves DAR from SPRN_DAR, and EX_DAR is not used. So EX_R3 can overlap
+ * with EX_DAR.
+ */
+#define EX_R3		EX_DAR
+
 #ifdef __ASSEMBLY__
 
 /*
-- 
2.11.0

  parent reply	other threads:[~2017-05-21 13:16 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-21 13:15 [PATCH 0/9] Reduce PACA save areas Nicholas Piggin
2017-05-21 13:15 ` [PATCH 1/9] powerpc/64s: slb_allocate_realmode() preserve r3 Nicholas Piggin
2017-06-22 13:12   ` [1/9] " Michael Ellerman
2017-05-21 13:15 ` [PATCH 2/9] powerpc/64s: SLB miss handler avoid saving faulting address into EX_DAR Nicholas Piggin
2017-05-21 13:15 ` [PATCH 3/9] powerpc/64s: SLB miss already has CTR saved for relocatable kernel Nicholas Piggin
2017-06-19 11:45   ` Michael Ellerman
2017-06-19 17:20     ` Nicholas Piggin
2017-05-21 13:15 ` [PATCH 4/9] powerpc/64s: SLB miss handler avoid r3 save/restore Nicholas Piggin
2017-06-19  4:48   ` Michael Ellerman
2017-06-19 16:54     ` Nicholas Piggin
2017-05-21 13:15 ` [PATCH 5/9] powerpc/64s: paca add EX_SIZE definition for exception save areas Nicholas Piggin
2017-05-21 13:15 ` [PATCH 6/9] powerpc/64s: paca EX_SRR0 is unused, remove it Nicholas Piggin
2017-05-21 13:15 ` [PATCH 7/9] powerpc/64s: paca EX_LR can be merged with EX_DAR Nicholas Piggin
2017-05-21 13:15 ` Nicholas Piggin [this message]
2017-05-21 13:15 ` [PATCH 9/9] powerpc/64s: paca EX_CTR is not used with !RELOCATABLE, remove it Nicholas Piggin

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