Currently if you disable CONFIG_PPC_RADIX_MMU you'll crash on boot on
a P9. This is because we still set MMU_FTR_TYPE_RADIX via
ibm,pa-features and MMU_FTR_TYPE_RADIX is what's used for code patching
in much of the asm code (ie. slb_miss_realmode)

This patch fixes the problem by stopping MMU_FTR_TYPE_RADIX from being
set from ibm.pa-features.

We may eventually end up removing the CONFIG_PPC_RADIX_MMU option
completely but until then this fixes the issue.

Fixes: 17a3dd2f5fc7 ("powerpc/mm/radix: Use firmware feature to enable Radix MMU")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The ibm,powerpc-cpu-features device tree binding describes CPU features with
ASCII names and extensible compatibility, privilege, and enablement metadata
that allows improved flexibility and compatibility with new hardware.

The interface is described in detail in ibm,powerpc-cpu-features.txt in this
patch.

Currently this code is not enabled by default, and there are no released
firmwares that provide the binding.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

These files don't seem to have any need for asm/debug.h, now that all it
includes are the debugger hooks and breakpoint definitions.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Commit 2965faa5e03d ("kexec: split kexec_load syscall from kexec core
code") introduced CONFIG_KEXEC_CORE so that CONFIG_KEXEC means whether
the kexec_load system call should be compiled-in and CONFIG_KEXEC_FILE
means whether the kexec_file_load system call should be compiled-in.
These options can be set independently from each other.

Since until now powerpc only supported kexec_load, CONFIG_KEXEC and
CONFIG_KEXEC_CORE were synonyms. That is not the case anymore, so we
need to make a distinction. Almost all places where CONFIG_KEXEC was
being used should be using CONFIG_KEXEC_CORE instead, since
kexec_file_load also needs that code compiled in.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The ibm_pa_features array consists of structures that describe which bit
and byte in the ibm,pa-features property toggles one or more flags in
either the CPU, MMU, or user visible feature flags.

Each one consists of 7 values, which are all unsigned long, int or char,
meaning the compiler gives us no warning if we assign the wrong values
to the wrong elements. In fact we have had a bug here in the past, where
we were setting incorrect bits, see commit 6997e57d693b ("powerpc:
scan_features() updates incorrect bits for REAL_LE").

So switch to using named initialisers for the structure elements, to
reduce the likelihood of future bugs, and hopefully improve readability
also.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>

MMU feature bits are defined such that we use the lower half to
present MMU family features. Remove the strict split of half and
also move Radix to a mmu family feature. Radix introduce a new MMU
model and strictly speaking it is a new MMU family. This also free
up bits which can be used for individual features later.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Move the handling of the disable_radix command line argument into the
newly created mmu_early_init_devtree().

It's an MMU option so it's preferable to have it in an mm related file,
and it also means platforms that don't support radix don't have to carry
the code.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Empty for now, but we'll add to it in the next patch.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We move it into early_mmu_init() based on firmware features. For PS3,
we have to move the setting of these into early_init_devtree().

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We move the function itself to pseries/firmware.c and call it along
with almost all other flat device-tree parsers from early_init_devtree()

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Move #ifdefs into the header by providing pseries_probe_fw_features()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>