linux-kernel - [PATCH 5.15 759/779] powerpc: Fix eh field when calling lwarx on PPC32

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Date:   Mon, 15 Aug 2022 20:06:43 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Pali Rohár <pali@...nel.org>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Segher Boessenkool <segher@...nel.crashing.org>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 5.15 759/779] powerpc: Fix eh field when calling lwarx on PPC32

From: Christophe Leroy <christophe.leroy@...roup.eu>

commit 18db466a9a306406dab3b134014d9f6ed642471c upstream.

Commit 9401f4e46cf6 ("powerpc: Use lwarx/ldarx directly instead of
PPC_LWARX/LDARX macros") properly handled the eh field of lwarx
in asm/bitops.h but failed to clear it for PPC32 in
asm/simple_spinlock.h

So, do as in arch_atomic_try_cmpxchg_lock(), set it to 1 if PPC64
but set it to 0 if PPC32. For that use IS_ENABLED(CONFIG_PPC64) which
returns 1 when CONFIG_PPC64 is set and 0 otherwise.

Fixes: 9401f4e46cf6 ("powerpc: Use lwarx/ldarx directly instead of PPC_LWARX/LDARX macros")
Cc: stable@...r.kernel.org # v5.15+
Reported-by: Pali Rohár <pali@...nel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
Tested-by: Pali Rohár <pali@...nel.org>
Reviewed-by: Segher Boessenkool <segher@...nel.crashing.org>
[mpe: Use symbolic names, use 'n' constraint per Segher]
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/a1176e19e627dd6a1b8d24c6c457a8ab874b7d12.1659430931.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/powerpc/include/asm/simple_spinlock.h |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

--- a/arch/powerpc/include/asm/simple_spinlock.h
+++ b/arch/powerpc/include/asm/simple_spinlock.h
@@ -48,10 +48,11 @@ static inline int arch_spin_is_locked(ar
 static inline unsigned long __arch_spin_trylock(arch_spinlock_t *lock)
 {
 	unsigned long tmp, token;
+	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
 
 	token = LOCK_TOKEN;
 	__asm__ __volatile__(
-"1:	lwarx		%0,0,%2,1\n\
+"1:	lwarx		%0,0,%2,%[eh]\n\
 	cmpwi		0,%0,0\n\
 	bne-		2f\n\
 	stwcx.		%1,0,%2\n\
@@ -59,7 +60,7 @@ static inline unsigned long __arch_spin_
 	PPC_ACQUIRE_BARRIER
 "2:"
 	: "=&r" (tmp)
-	: "r" (token), "r" (&lock->slock)
+	: "r" (token), "r" (&lock->slock), [eh] "n" (eh)
 	: "cr0", "memory");
 
 	return tmp;
@@ -177,9 +178,10 @@ static inline void arch_spin_unlock(arch
 static inline long __arch_read_trylock(arch_rwlock_t *rw)
 {
 	long tmp;
+	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
 
 	__asm__ __volatile__(
-"1:	lwarx		%0,0,%1,1\n"
+"1:	lwarx		%0,0,%1,%[eh]\n"
 	__DO_SIGN_EXTEND
 "	addic.		%0,%0,1\n\
 	ble-		2f\n"
@@ -187,7 +189,7 @@ static inline long __arch_read_trylock(a
 	bne-		1b\n"
 	PPC_ACQUIRE_BARRIER
 "2:"	: "=&r" (tmp)
-	: "r" (&rw->lock)
+	: "r" (&rw->lock), [eh] "n" (eh)
 	: "cr0", "xer", "memory");
 
 	return tmp;
@@ -200,17 +202,18 @@ static inline long __arch_read_trylock(a
 static inline long __arch_write_trylock(arch_rwlock_t *rw)
 {
 	long tmp, token;
+	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
 
 	token = WRLOCK_TOKEN;
 	__asm__ __volatile__(
-"1:	lwarx		%0,0,%2,1\n\
+"1:	lwarx		%0,0,%2,%[eh]\n\
 	cmpwi		0,%0,0\n\
 	bne-		2f\n"
 "	stwcx.		%1,0,%2\n\
 	bne-		1b\n"
 	PPC_ACQUIRE_BARRIER
 "2:"	: "=&r" (tmp)
-	: "r" (token), "r" (&rw->lock)
+	: "r" (token), "r" (&rw->lock), [eh] "n" (eh)
 	: "cr0", "memory");
 
 	return tmp;