Hi Christophe,
On Thu, 2019-08-08 at 12:48 +0000, Christophe Leroy wrote:
> Santa 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 make SMP hang
> when CONFIG_PREEMPT is set.
>
> Reported-by: Chris Packham <[email protected]>
> Fixes: ebb9d30a6a74 ("powerpc/mm: any thread in one core can be the
> first to setup TLB1")
> Link: https://github.com/linuxppc/issues/issues/264
> Signed-off-by: Christophe Leroy <[email protected]>
> Cc: [email protected]
Many thanks for your help.
Tested-by: Chris Packham <[email protected]>
> ---
> arch/powerpc/mm/nohash/tlb.c | 1 -
> 1 file changed, 1 deletion(-)
>
> 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
> */
