The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From b9ee5e04fd77898208c51b1395fa0b5e8536f9b6 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@xxxxxx>
Date: Thu, 8 Aug 2019 12:48:26 +0000
Subject: [PATCH] powerpc/64e: Drop stale call to smp_processor_id() which
hangs SMP startup
Commit ebb9d30a6a74 ("powerpc/mm: any thread in one core can be the
first to setup TLB1") removed the need to know the cpu_id in
early_init_this_mmu(), but the call to smp_processor_id() which was
marked __maybe_used remained.
Since commit ed1cd6deb013 ("powerpc: Activate CONFIG_THREAD_INFO_IN_TASK")
thread_info cannot be reached before MMU is properly set up.
Drop this stale call to smp_processor_id() which makes SMP hang when
CONFIG_PREEMPT is set.
Fixes: ebb9d30a6a74 ("powerpc/mm: any thread in one core can be the first to setup TLB1")
Fixes: ed1cd6deb013 ("powerpc: Activate CONFIG_THREAD_INFO_IN_TASK")
Cc: stable@xxxxxxxxxxxxxxx # v5.1+
Reported-by: Chris Packham <Chris.Packham@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
Tested-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/bef479514f4c08329fa649f67735df8918bc0976.1565268248.git.christophe.leroy@xxxxxx
diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c
index d4acf6fa0596..bf60983a58c7 100644
--- a/arch/powerpc/mm/nohash/tlb.c
+++ b/arch/powerpc/mm/nohash/tlb.c
@@ -630,7 +630,6 @@ static void early_init_this_mmu(void)
#ifdef CONFIG_PPC_FSL_BOOK3E
if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
unsigned int num_cams;
- int __maybe_unused cpu = smp_processor_id();
bool map = true;
/* use a quarter of the TLBCAM for bolted linear map */
