powerpc: Fix incorrect stw{, ux, u, x} instructions in __set_pte_at

[ Upstream commit d85be8a49e733dcd23674aa6202870d54bf5600d ]

The placeholder for instruction selection should use the second
argument's operand, which is %1, not %0. This could generate incorrect
assembly code if the memory addressing of operand %0 is a different
form from that of operand %1.

Also remove the %Un placeholder because having %Un placeholders
for two operands which are based on the same local var (ptep) doesn't
make much sense. By the way, it doesn't change the current behaviour
because "<>" constraint is missing for the associated "=m".

[chleroy: revised commit log iaw segher's comments and removed %U0]

Fixes: 9bf2b5cdc5fe ("powerpc: Fixes for CONFIG_PTE_64BIT for SMP support")
Cc: <stable@vger.kernel.org> # v2.6.28+
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/96354bd77977a6a933fe9020da57629007fdb920.1603358942.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index b64b4212b71f6fdba013f3f6b805528bcad1a221..408f9e1fa24ac2285d867fda3a0670e7be0d5d89 100644 (file)
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -149,9 +149,9 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
                flush_hash_entry(mm, ptep, addr);
 #endif
        __asm__ __volatile__("\
-               stw%U0%X0 %2,%0\n\
+               stw%X0 %2,%0\n\
                eieio\n\
-               stw%U0%X0 %L2,%1"
+               stw%X1 %L2,%1"
        : "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
        : "r" (pte) : "memory");