[PATCH v6 17/18] powerpc/64s: Move hash MMU support code under CONFIG_PPC_64S_HASH_MMU

[Michael Ellerman]

Nicholas Piggin <npiggin at gmail.com> writes:
> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
> index 015d7d972d16..c480d21a146c 100644
> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
> @@ -239,8 +251,9 @@ static inline void setup_initial_memory_limit(phys_addr_t first_memblock_base,
>  	 * know which translations we will pick. Hence go with hash
>  	 * restrictions.
>  	 */
> -	return hash__setup_initial_memory_limit(first_memblock_base,
> -					   first_memblock_size);
> +	if (!radix_enabled())
> +		hash__setup_initial_memory_limit(first_memblock_base,
> +						 first_memblock_size);
>  }

This needs to use early_radix_enabled(), it's called before jump label
patching.

With the jump label feature check debugging on you get a warning:

  Booting Linux via __start() @ 0x0000000000400000 ...
  [    0.000000][    T0] Warning! mmu_has_feature() used prior to jump label init!
  [    0.000000][    T0] CPU: 0 PID: 0 Comm: swapper Not tainted 5.16.0-rc2-00167-ga2397104dbef #149
  [    0.000000][    T0] Call Trace:
  [    0.000000][    T0] [c000000002843e20] [c000000000894d40] dump_stack_lvl+0x74/0xa8 (unreliable)
  [    0.000000][    T0] [c000000002843e60] [c000000002009a28] early_init_devtree+0x164/0x554
  [    0.000000][    T0] [c000000002843f10] [c00000000200b3d4] early_setup+0xc8/0x280
  [    0.000000][    T0] [c000000002843f90] [000000000000d368] 0xd368


Or otherwise a really obscure crash :D

cheers