On powerpc32, patch_instruction() is called by apply_feature_fixups()
which is called from early_init()
There is the following note in front of early_init():
* Note that the kernel may be running at an address which is different
* from the address that it was linked at, so we must use RELOC/PTRRELOC
* to access static data (including strings). -- paulus
Therefore, slab_is_available() cannot be called yet, and
text_poke_area must be addressed with PTRRELOC()
Fixes: 95902e6c88 ("powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32")
Cc: stable@vger.kernel.org # v4.14+
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
252eb55816