[PATCH 4.18 274/350] powerpc/64s/hash: Do not use PPC_INVALIDATE_ERAT on CPUs before POWER9

Greg Kroah-Hartman
2018-11-11T23:18:30Z

From: Nicholas Piggin <npiggin@gmail.com>

commit bc276ecba132caccb1fda5863a652c15def2b8c6 upstream.

PPC_INVALIDATE_ERAT is slbia IH=7 which is a new variant introduced
with POWER9, and the result is undefined on earlier CPUs.

Commits 7b9f71f974 ("powerpc/64s: POWER9 machine check handler") and
d4748276ae ("powerpc/64s: Improve local TLB flush for boot and MCE on
POWER9") caused POWER7/8 code to use this instruction. Remove it. An
ERAT flush can be made by invalidatig the SLB, but before POWER9 that
requires a flush and rebolt.

Fixes: 7b9f71f974 ("powerpc/64s: POWER9 machine check handler")
Fixes: d4748276ae ("powerpc/64s: Improve local TLB flush for boot and MCE on POWER9")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/kernel/mce_power.c | 7 +++++++
arch/powerpc/mm/hash_native_64.c | 4 ++--
2 files changed, 9 insertions(+), 2 deletions(-)

--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -97,6 +97,13 @@ static void flush_and_reload_slb(void)

static void flush_erat(void)
{
+#ifdef CONFIG_PPC_BOOK3S_64
+ if (!early_cpu_has_feature(CPU_FTR_ARCH_300)) {
+ flush_and_reload_slb();
+ return;
+ }
+#endif
+ /* PPC_INVALIDATE_ERAT can only be used on ISA v3 and newer */
asm volatile(PPC_INVALIDATE_ERAT : : :"memory");
}

--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -115,6 +115,8 @@ static void tlbiel_all_isa300(unsigned i
tlbiel_hash_set_isa300(0, is, 0, 2, 1);

asm volatile("ptesync": : :"memory");
+
+ asm volatile(PPC_INVALIDATE_ERAT "; isync" : : :"memory");
}

void hash__tlbiel_all(unsigned int action)
@@ -140,8 +142,6 @@ void hash__tlbiel_all(unsigned int actio
tlbiel_all_isa206(POWER7_TLB_SETS, is);
else
WARN(1, "%s called on pre-POWER7 CPU\n", __func__);
-
- asm volatile(PPC_INVALIDATE_ERAT "; isync" : : :"memory");
}

static inline unsigned long ___tlbie(unsigned long vpn, int psize,