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c8b00bb742
With preempt enabled we see warnings in do_slb_fault():
BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u33:0/98
futex hash table entries: 4096 (order: 3, 524288 bytes)
caller is do_slb_fault+0x204/0x230
CPU: 5 PID: 98 Comm: kworker/u33:0 Not tainted 4.19.0-rc3-gcc-7.3.1-00022-g1936f094e164 #138
Call Trace:
dump_stack+0xb4/0x104 (unreliable)
check_preemption_disabled+0x148/0x150
do_slb_fault+0x204/0x230
data_access_slb_common+0x138/0x180
This is caused by the get_paca() in slb_allocate_kernel(), which
includes a call to debug_smp_processor_id().
slb_allocate_kernel() can only be called from do_slb_fault(), and in
that path interrupts are hard disabled and so we can't be preempted,
but we can't update the preempt flags (in thread_info) because that
could cause an SLB fault.
So just use local_paca which is safe and doesn't cause the warning.
Fixes: 48e7b76957 ("powerpc/64s/hash: Convert SLB miss handlers to C")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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