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 <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 56f7a2b793e0cc3d603e2b14d476659db3994abd..0af5c11b9e784f21b3cd799bee34edc5d48a7d9c 100644 (file)
--- 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