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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	 mathieu.desnoyers@efficios.com
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/3] powerpc: Fix update form addressing in inline assembly
Date: Tue, 20 Oct 2020 07:40:09 +0000 (UTC)	[thread overview]
Message-ID: <fcff4199459890d107a06dbc39c52668ccd0921b.1603179582.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <212d3bc4a52ca71523759517bb9c61f7e477c46a.1603179582.git.christophe.leroy@csgroup.eu>

In several places, inline assembly uses the "%Un" modifier
to enable the use of instruction with update form addressing,
but the associated "<>" constraint is missing.

As mentioned in previous patch, this fails with gcc 4.9, so
"<>" can't be used directly.

Use UPD_CONSTR macro everywhere %Un modifier is used.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2: Build failure (circular inclusion) fixed by change in patch 1
---
 arch/powerpc/include/asm/atomic.h            | 9 +++++----
 arch/powerpc/include/asm/book3s/32/pgtable.h | 2 +-
 arch/powerpc/include/asm/io.h                | 4 ++--
 arch/powerpc/include/asm/nohash/pgtable.h    | 2 +-
 arch/powerpc/kvm/powerpc.c                   | 4 ++--
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h
index 8a55eb8cc97b..61c6e8b200e8 100644
--- a/arch/powerpc/include/asm/atomic.h
+++ b/arch/powerpc/include/asm/atomic.h
@@ -10,6 +10,7 @@
 #include <linux/types.h>
 #include <asm/cmpxchg.h>
 #include <asm/barrier.h>
+#include <asm/asm-const.h>
 
 /*
  * Since *_return_relaxed and {cmp}xchg_relaxed are implemented with
@@ -26,14 +27,14 @@ static __inline__ int atomic_read(const atomic_t *v)
 {
 	int t;
 
-	__asm__ __volatile__("lwz%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
+	__asm__ __volatile__("lwz%U1%X1 %0,%1" : "=r"(t) : "m"UPD_CONSTR(v->counter));
 
 	return t;
 }
 
 static __inline__ void atomic_set(atomic_t *v, int i)
 {
-	__asm__ __volatile__("stw%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
+	__asm__ __volatile__("stw%U0%X0 %1,%0" : "=m"UPD_CONSTR(v->counter) : "r"(i));
 }
 
 #define ATOMIC_OP(op, asm_op)						\
@@ -316,14 +317,14 @@ static __inline__ s64 atomic64_read(const atomic64_t *v)
 {
 	s64 t;
 
-	__asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
+	__asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m"UPD_CONSTR(v->counter));
 
 	return t;
 }
 
 static __inline__ void atomic64_set(atomic64_t *v, s64 i)
 {
-	__asm__ __volatile__("std%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
+	__asm__ __volatile__("std%U0%X0 %1,%0" : "=m"UPD_CONSTR(v->counter) : "r"(i));
 }
 
 #define ATOMIC64_OP(op, asm_op)						\
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 34f5ca391f0c..0e1b6e020cef 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -525,7 +525,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
 		stw%U0%X0 %2,%0\n\
 		eieio\n\
 		stw%U1%X1 %L2,%1"
-	: "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
+	: "=m"UPD_CONSTR (*ptep), "=m"UPD_CONSTR (*((unsigned char *)ptep+4))
 	: "r" (pte) : "memory");
 
 #else
diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 58635960403c..87964dfb838e 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -122,7 +122,7 @@ static inline u##size name(const volatile u##size __iomem *addr)	\
 {									\
 	u##size ret;							\
 	__asm__ __volatile__("sync;"#insn"%U1%X1 %0,%1;twi 0,%0,0;isync"\
-		: "=r" (ret) : "m" (*addr) : "memory");			\
+		: "=r" (ret) : "m"UPD_CONSTR (*addr) : "memory");	\
 	return ret;							\
 }
 
@@ -130,7 +130,7 @@ static inline u##size name(const volatile u##size __iomem *addr)	\
 static inline void name(volatile u##size __iomem *addr, u##size val)	\
 {									\
 	__asm__ __volatile__("sync;"#insn"%U0%X0 %1,%0"			\
-		: "=m" (*addr) : "r" (val) : "memory");			\
+		: "=m"UPD_CONSTR (*addr) : "r" (val) : "memory");	\
 	mmiowb_set_pending();						\
 }
 
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index a00e4c1746d6..55ef2112ed00 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -200,7 +200,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
 			stw%U0%X0 %2,%0\n\
 			eieio\n\
 			stw%U1%X1 %L2,%1"
-		: "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
+		: "=m"UPD_CONSTR (*ptep), "=m"UPD_CONSTR (*((unsigned char *)ptep+4))
 		: "r" (pte) : "memory");
 		return;
 	}
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 13999123b735..cf52d26f49cd 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -1087,7 +1087,7 @@ static inline u64 sp_to_dp(u32 fprs)
 
 	preempt_disable();
 	enable_kernel_fp();
-	asm ("lfs%U1%X1 0,%1; stfd%U0%X0 0,%0" : "=m" (fprd) : "m" (fprs)
+	asm ("lfs%U1%X1 0,%1; stfd%U0%X0 0,%0" : "=m"UPD_CONSTR (fprd) : "m"UPD_CONSTR (fprs)
 	     : "fr0");
 	preempt_enable();
 	return fprd;
@@ -1099,7 +1099,7 @@ static inline u32 dp_to_sp(u64 fprd)
 
 	preempt_disable();
 	enable_kernel_fp();
-	asm ("lfd%U1%X1 0,%1; stfs%U0%X0 0,%0" : "=m" (fprs) : "m" (fprd)
+	asm ("lfd%U1%X1 0,%1; stfs%U0%X0 0,%0" : "=m"UPD_CONSTR (fprs) : "m"UPD_CONSTR (fprd)
 	     : "fr0");
 	preempt_enable();
 	return fprs;
-- 
2.25.0


  parent reply	other threads:[~2020-10-20  7:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20  7:40 [PATCH v2 1/3] powerpc/uaccess: Don't use "m<>" constraint with GCC 4.9 Christophe Leroy
2020-10-20  7:40 ` [PATCH v2 2/3] powerpc: Fix incorrect stw{, ux, u, x} instructions in __set_pte_at Christophe Leroy
2020-10-20  7:40 ` Christophe Leroy [this message]
2020-10-20 12:16   ` [PATCH v2 3/3] powerpc: Fix update form addressing in inline assembly Segher Boessenkool
2020-10-24 10:27 ` [PATCH v2 1/3] powerpc/uaccess: Don't use "m<>" constraint with GCC 4.9 Michael Ellerman

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