When compiled with GCC 8.1, vmlinux is significantly bigger than
with GCC 4.8.

When looking at the generated code with objdump, we notice that
all functions and loops when a 16 bytes alignment. This significantly
increases the size of the kernel. It is pointless and even
counterproductive as on the 8xx 'nop' also consumes one clock cycle.

Size of vmlinux with GCC 4.8:
   text	   data	    bss	    dec	    hex	filename
5801948	1626076	 457796	7885820	 7853fc	vmlinux

Size of vmlinux with GCC 8.1:
   text	   data	    bss	    dec	    hex	filename
6764592	1630652	 456476	8851720	 871108	vmlinux

Size of vmlinux with GCC 8.1 and this patch:
   text	   data	    bss	    dec	    hex	filename
6331544	1631756	 456476	8419776	 8079c0	vmlinux
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The powerpc toolchain can compile combinations of 32/64 bit and
big/little endian, so it's convenient to consider, e.g.,

  `CC -m64 -mbig-endian`

To be the C compiler for the purpose of invoking it to build target
artifacts. So overriding the CC variable to include these flags works
for this purpose.

Unfortunately that is not compatible with the way the proposed new
Kconfig macro language will work.

After previous patches in this series, these flags can be carefully
passed in using flags instead.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Switch VDSO32 build over to use CROSS32_COMPILE directly, and have
it pass in -m32 after the standard c_flags. This allows endianness
overrides to be removed and the endian and bitness flags moved into
standard flags variables.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Some 64-bit toolchains uses the wrong ISA variant for compiling 32-bit
kernels, even with -m32. Debian's powerpc64le is one such case, and
that is because it is built with --with-cpu=power8.

So when cross compiling a 32-bit kernel with a 64-bit toolchain, set
-mcpu=powerpc initially, which is the generic 32-bit powerpc machine
type and scheduling model. CPU and platform code can override this
with subsequent -mcpu flags if necessary.

This is not done for 32-bit toolchains otherwise it would override
their defaults, which are presumably set appropriately for the
environment (moreso than a 64-bit cross compiler).

This fixes a lot of build failures due to incompatible assembly when
compiling 32-bit kernel with the Debian powerpc64le 64-bit toolchain.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

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

Add GENERIC_CPU support for little-endian rather than using POWER8
specific selection for POWER9 and above.

Restrict GENERIC_CPU to POWER8 and above on little endian.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
[mpe: Duplicate GENERIC_CPU to avoid a kbuild warning about the prompt
      being redefined. Spell out that GENERIC means >= POWER4 for BE.]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

POWER4 has been broken since at least the change 49d09bf2
("powerpc/64s: Optimise MSR handling in exception handling"), which
requires mtmsrd L=1 support. This was introduced in ISA v2.01, and
POWER4 supports ISA v2.00.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Rather than override the machine type in .S code (which can hide wrong
or ambiguous code generation for the target), set the type to power4
for all assembly.

This also means we need to be careful not to build power4-only code
when we're not building for Book3S, such as the "power7" versions of
copyuser/page/memcpy.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
[mpe: Fix Book3E build, don't build the "power7" variants for non-Book3S]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Newer gcc will support "-mno-readonly-in-sdata"[1], which makes sure that
the optimization on PPC32 for variables getting moved into the .sdata
section will not apply to const variables (which must be in .rodata).

This was originally noticed in mm/rodata_test.c when rodata_test_data
was not static:

c0695034 g     O .data	00000004 rodata_test_data

After this patch with an updated compiler, this is correctly in .rodata.

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82411Reported-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NSegher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

powerpc64 gcc can generate code that offsets an address, to access
part of an object in memory. If the address is a -mcmodel=medium toc
pointer relative address then code like the following is possible.

  addis r9,r2,var@toc@ha
  ld r3,var@toc@l(r9)
  ld r4,(var+8)@toc@l(r9)

This works fine so long as var is naturally aligned, *and* r2 is
sufficiently aligned. If not, there is a possibility that the offset
added to access var+8 wraps over a n*64k+32k boundary. Modules don't
have any guarantee that r2 is sufficiently aligned. Moreover, code
generated by older compilers generates a .toc section with 2**0
alignment, which can result in relocation failures at module load time
even without the wrap problem.

Thus, this patch links modules with an aligned .toc section (Makefile
and module.lds changes), and forces alignment for out of tree modules
or those without a .toc section (module_64.c changes).
Signed-off-by: NAlan Modra <amodra@gmail.com>
[desnesn: updated patch to apply to powerpc-next kernel v4.15 ]
Signed-off-by: NDesnes A. Nunes do Rosario <desnesn@linux.vnet.ibm.com>
[mpe: Fix out-of-tree build, swap -256 for ~0xff, reflow comment]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Two config options exist to define powerpc MPC8xx:
* CONFIG_PPC_8xx
* CONFIG_8xx

arch/powerpc/platforms/Kconfig.cputype has contained the following
comment about CONFIG_8xx item for some years:
"# this is temp to handle compat with arch=ppc"

arch/powerpc is now the only place with remaining use of
CONFIG_8xx: get rid of them.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Although pretty much everyone using powernv is running little endian,
we should still test we can build for big endian. So add a
powernv_be_defconfig, which is autogenerated by flipping the endian
symbol in powernv_defconfig.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: NCyril Bur <cyrilbur@gmail.com>

In commit efe0160c ("powerpc/64: Linker on-demand sfpr functions
for modules"), we added an ld version check early in the powerpc
top-level Makefile.

Because the Makefile runs before the kernel config is setup, the
checks for CONFIG_CPU_LITTLE_ENDIAN etc. all take the default case. So
we end up configuring ld for 32-bit big endian.

That would be OK, except that for historical (or perhaps no) reason,
we use 'override LD' to add the endian flags to the LD variable
itself, rather than the normal approach of adding them to LDFLAGS.

The end result is that when we check the ld version we run it as:

  $(CROSS_COMPILE)ld -EB -m elf32ppc --version

This often works, unless you are using a 64-bit only and/or little
endian only, toolchain. In which case you see something like:

  $ make defconfig
  powerpc64le-linux-ld: unrecognised emulation mode: elf32ppc
  Supported emulations: elf64lppc elf32lppc elf32lppclinux elf32lppcsim
  /bin/sh: 1: [: -ge: unexpected operator

The proper fix is to stop using 'override LD', but that will require a
fair bit of testing. Instead we can fix it for now just by reordering
the Makefile to do the version check earlier.

Fixes: efe0160c ("powerpc/64: Linker on-demand sfpr functions for modules")
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Add --orphan-handling=warn to final link flags. This ensures we can
handle all sections explicitly. This would have caught subtle breakage
such as 7de3b27b at build-time.

Also bring existing orphan sections into the fold:
- .text.hot and .text.unlikely are compiler generated sections.
- .sdata2, .dynsbss, .plt are used by PPC32
- We previously did not specify DWARF_DEBUG or STABS_DEBUG
- DWARF_DEBUG did not include all DWARF sections that can be emitted
- A number of sections are unused and can be discarded.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

For final link, the powerpc64 linker generates fpr save/restore
functions on-demand, placing them in the .sfpr section. Starting with
binutils 2.25, these can be provided for non-final links with
--save-restore-funcs. Use that where possible for module links.

This saves about 200 bytes per module (~60kB) on powernv defconfig
build.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Move a couple of existing scripts under there. Remove scripts directory:
a script is a tool, a tool is not a script.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently powerpc has to introduce a dependency on its default build
target zImage in order to run a relocation check pass over the linked
vmlinux. This is deficient because the check is not run if the plain
vmlinux target is built, or if one of the other boot targets is built.

Switch to using the kbuild post-link pass, added in commit fbe6e37d
("kbuild: add arch specific post-link Makefile") in order to run this
check. In future powerpc will use this to do more complicated operations,
but initially using it for something simple is a good first step.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

GCC can compile with either endian, but the default ABI version is set
based on the default endianness of the toolchain. Alan Modra says:

  you need both -mbig and -mabi=elfv1 to make a powerpc64le gcc
  generate powerpc64 code

The opposite is true for powerpc64 when generating -mlittle it
requires -mabi=elfv2 to generate v2 ABI, which we were already doing.

This change adds ABI annotations together with endianness for all cases,
LE and BE. This fixes the case of building a BE kernel with a toolchain
that is LE by default.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Tested-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This purgatory implementation is based on the versions from kexec-tools
and kexec-lite, with additional changes.
Signed-off-by: NThiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Back in 2005 when the ppc/ppc64 merge started, we used to build the
kernel code in arch/powerpc but use the boot code from arch/ppc or
arch/ppc64 depending on whether we were building for 32 or 64-bit.

Originally we called the boot Makefile passing ARCH=$(OLDARCH), where
OLDARCH was ppc or ppc64.

In commit 20f62954 ("powerpc: Make building the boot image work for
both 32-bit and 64-bit") (2005-10-11) we split the call for 32/64-bit
using an ifeq check, because the two Makefiles took different targets,
and explicitly passed ARCH=ppc64 for the 64-bit case and ARCH=ppc for
the 32-bit case.

Then in commit 94b212c2 ("powerpc: Move ppc64 boot wrapper code over
to arch/powerpc") (2005-11-16) we moved the boot code into arch/powerpc
and dropped the ppc case, but kept passing ARCH=ppc64 to
arch/powerpc/boot/Makefile.

Since then there have been several more boot targets added, all of which
have copied the ARCH=ppc64 setting, such that now we have four targets
using it.

Currently it seems that nothing actually uses the ARCH value, but that's
basically just luck, and in particular it prevents us from using the
generic cpp_lds_S rule. It's also clearly wrong, ARCH=ppc64 is dead,
buried and cremated.

Fix it by dropping the setting of ARCH completely, the correct value is
exported by the top level Makefile.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Add an option to use thin archives to build the kernel.
Thin archives are explained in commit a5967db9 ("kbuild: allow
architectures to use thin archives instead of ld -r").

This is a gradual way to introduce the option to testers.

Some change to the way we invoke ar is required so it can be used
by scripts/link-vmlinux.sh.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
[mpe: Make it an explicit option not dependant on COMPILE_TEST]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When we're not compiling for a specific CPU, ie. none of the
CONFIG_POWERx_CPU options are set, and CONFIG_GENERIC_CPU *is* set, we
currently don't pass any -mcpu option to the compiler. This means the
compiler builds for a "generic" Power CPU.

But back in 2014 we dropped support for pre power4 CPUs in commit
468a3302 ("powerpc: Drop support for pre-POWER4 cpus").

Given that, there's no point in building the kernel to run on pre power4
cpus. So update the flags we pass to the compiler when
CONFIG_GENERIC_CPU is set, to specify -mcpu=power4.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Enable the drivers on the powerpc arch.
Signed-off-by: NRoy Pledge <roy.pledge@nxp.com>
Signed-off-by: NClaudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: NScott Wood <oss@buserror.net>

Use the standard Kbuild trick of foo-y to make the construction of
UTC_MACHINE less verbose.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Commit 2578bfae ("[POWERPC] Create and use CONFIG_WORD_SIZE") added
CONFIG_WORD_SIZE, and suggests that other arches were going to do
likewise.

But that never happened, powerpc is the only architecture which uses it.

So switch to using a simple make variable, BITS, like x86, sh, sparc and
tile. It is also easier to spell and simpler, avoiding any confusion
about whether it's defined due to ordering of make vs kconfig.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

In fact it makes no sense at all to have this defined on little endian
builds. Since we disabled the 32-bit VDSO on little endian, we don't
build any 32-bit code when building a little endian kernel.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When we introduced the little endian support, we added the endian flags
to CC directly using override. I don't know the history of why we did
that, I suspect no one does.

Although this mostly works, it has one bug, which is that CROSS32CC
doesn't get -mbig-endian. That means when the compiler is little endian
by default and the user is building big endian, vdso32 is incorrectly
compiled as little endian and the kernel fails to build.

Instead we can add the endian flags to cflags-y/aflags-y, and then
append those to KBUILD_CFLAGS/KBUILD_AFLAGS.

This has the advantage of being 1) less ugly, 2) the documented way of
adding flags in the arch Makefile and 3) it fixes building vdso32 with a
LE toolchain.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Explicitly give sparse an endianness in the Makefile, so that it
doesn't get confused.

Normally we have #ifdef one and #else the other, so it doesn't usually
matter, but we have been bitten by it before, and indeed this patch
fixes a number of sparse errors.
Suggested-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDaniel Axtens <dja@axtens.net>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Check the assembler supports -maltivec by wrapping it with
call as-option.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Signed-off-by: NAlessio Igor Bogani <alessio.bogani@elettra.eu>
Signed-off-by: NScott Wood <oss@buserror.net>

Firstly we add logic to Kconfig to allow a user to choose if they want
mprofile-kernel. This has to be user-selectable because only some
current toolchains support it. If we enabled it unconditionally we would
prevent some users from building the kernel entirely.

Arguably it would be nice if we could detect if mprofile-kernel was
available, and use it then. However that would violate the principle of
least surprise because a user having choosen options such as live
patching, would then see them quietly disabled at build time.

We also make the user selectable option negative, ie. it disables when
selected, so that allyesconfig continues to build on old toolchains.

Once we've decided we do want to use mprofile-kernel, we then add a
script which checks it actually works. That is because there are
versions of gcc that accept the flag but don't generate correct code.

Due to the way kconfig works, we can't error out when we detect a
non-working toolchain. If we did a user would never be able to modify
their config and run oldconfig - because the check would block oldconfig
from running. Instead we emit a warning and add a bogus flag to CFLAGS
so that the build will fail.
Signed-off-by: NTorsten Duwe <duwe@suse.de>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The TUNE_CELL option allows you to build a kernel that runs on multiple
CPUs but is tuned (ie. optimised) to run on Cell CPUs. Now days no one
is building a distro in that fashion, and any users who are building
custom kernels for their Cell machines are better off building with
CONFIG_CELL_CPU, which builds a kernel that only runs on Cell and
therefore can be optimised even more aggresively.

Dropping the option also avoids confusing other users, who are presented
with an option to tune for Cell when they are not building for a Cell
CPU at all.
Suggested-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Based directly on ppc64_defconfig using merge_config.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We cannot detect clang before including the arch Makefile, because that
can set the default cross compiler. We also cannot detect clang after
including the arch Makefile, because powerpc wants to know about clang.
Solve this by using an deferred variable. This costs us a few shell
invocations, but this is only a constant number.
Reported-by: NBehan Webster <behanw@converseincode.com>
Reported-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichal Marek <mmarek@suse.com>

Unify mpc85xx and corenet configs using fragments, to ease maintenance
and avoid the sort of drift that the previous patch fixed.

Hardware and software options are separated, with the hope that other
embedded platforms could share the software options, and to make it
easier to maintain custom/alternate configs that focus on either
hardware or software options.

Due to the previous patch, this patch should not affect the results of
any of the affected defconfigs -- only how those results are achieved.
The resulting config is more or less the union of the options that any
of the configs previously selected.  No attempt was made in this (or
the previous) patch to edit out questionable options, but this patch
will make it easier to do so in future patches.
Signed-off-by: NScott Wood <scottwood@freescale.com>

We have code to choose between several options, eg. -mabi=elfv2 vs
-mcall-aixdesc, and -mcmodel=medium vs -mminimal-toc. But these are all
GCC specific, so use cc-option on all of them.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We added -mno-strict-align in commit f036b368 (powerpc: Work around little
endian gcc bug) to fix gcc bug http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57134

Clang doesn't understand it. We need to use a conditional because we can't use the
simpler call cc-option here.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

These options are not recognised on LLVM, so use call cc-option to check
for support.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Rather than continuing to maintain a copy of pseries_defconfig with
CONFIG_CPU_LITTLE_ENDIAN enabled, use the generic merge_config script
and use an le.config to enable little endian on top of pseries_defconfig
without the need for a duplicated _defconfig file.

This method will require less maintenance in the future and will ensure
that both 'defconfigs' are always in sync.

It is worth noting that the seemingly more simple approach of:

  pseries_le_defconfig: pseries_defconfig
  	$(Q)$(MAKE) le.config

Will not work when building using O=builddir.

The obvious fix to that:

  pseries_le_defconfig:
  	$(Q)$(MAKE) -f $(srctree)/Makefile pseries_defconfig le.config

Also does not work. This is because if we have for example:

config FOO
	depends on CPU_BIG_ENDIAN
	select BAR

Then BAR will be enabled by the first call to kconfig (via
pseries_defconfig), and then will remain enabled after we merge
le.config, even though FOO will have been turned off.

The solution is to ensure to only invoke the kconfig logic once, after
we have merged all the config fragments. This ensures nothing is
select'ed on that should then be disabled by the later merged configs.
This is done through the explicit call to make olddefconfig
Signed-off-by: NCyril Bur <cyrilbur@gmail.com>
Reviewed-by: NSamuel Mendoza-Jonas <sam.mj@au1.ibm.com>
[mpe: Massage change log, fix white space and use ARCH not SRCARCH]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

There is a bug in binutils 2.24 which causes miscompilation if we're
building little endian and using weak symbols (which the kernel does).

It is fixed in binutils commit 57fa7b8c7e59 "Correct elf_merge_st_other
arguments for weak symbols", which is in binutils 2.25 and has been
backported to the binutils 2.24 branch and has been picked up by most
distros it seems.

However if we're running stock 2.24 (no extra version) then the bug is
present, so check for that and bail.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>