[PATCH 5.18 1073/1095] powerpc: Fix eh field when calling lwarx on PPC32

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 19:42:53 EST


From: Christophe Leroy <christophe.leroy@xxxxxxxxxx>

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@xxxxxxxxxxxxxxx # v5.15+
Reported-by: Pali Rohár <pali@xxxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Tested-by: Pali Rohár <pali@xxxxxxxxxx>
Reviewed-by: Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx>
[mpe: Use symbolic names, use 'n' constraint per Segher]
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/a1176e19e627dd6a1b8d24c6c457a8ab874b7d12.1659430931.git.christophe.leroy@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
@@ -156,9 +157,10 @@ 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"
@@ -166,7 +168,7 @@ 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;
@@ -179,17 +181,18 @@ 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;