From 1d0afc0d5a7c281f8ced3bd39f61f3328d5d3822 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Sat, 31 Mar 2018 20:57:10 +1100 Subject: [PATCH] powerpc/64e: Fix oops due to deferral of paca allocation On 64-bit Book3E systems, in setup_tlb_core_data() we reference other CPUs pacas. But in commit 59f577743d71 ("powerpc/64: Defer paca allocation until memory topology is discovered") the allocation of non-boot-CPU pacas was deferred until later in boot. This leads to an oops: CPU maps initialized for 1 thread per core Unable to handle kernel paging request for data at address 0x8888888888888918 Faulting instruction address: 0xc000000000e2f0d0 Oops: Kernel access of bad area, sig: 11 [#1] NIP .setup_tlb_core_data+0xdc/0x160 Call Trace: .setup_tlb_core_data+0x5c/0x160 (unreliable) .setup_arch+0x80/0x348 .start_kernel+0x7c/0x598 start_here_common+0x1c/0x40 Luckily setup_tlb_core_data() is called immediately prior to smp_setup_pacas(). So simply switching their order is sufficient to fix the oops and seems unlikely to have any other unwanted side effects. Fixes: 59f577743d71 ("powerpc/64: Defer paca allocation until memory topology is discovered") Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/setup-common.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 56f7a2b..0af5c11 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -915,9 +915,6 @@ void __init setup_arch(char **cmdline_p) /* Parse memory topology */ mem_topology_setup(); - /* On BookE, setup per-core TLB data structures. */ - setup_tlb_core_data(); - /* * Release secondary cpus out of their spinloops at 0x60 now that * we can map physical -> logical CPU ids. @@ -927,6 +924,10 @@ void __init setup_arch(char **cmdline_p) */ #ifdef CONFIG_SMP smp_setup_pacas(); + + /* On BookE, setup per-core TLB data structures. */ + setup_tlb_core_data(); + smp_release_cpus(); #endif -- 2.7.4