Large decrementers (e.g., POWER9) can take a very long time to wrap,
so when the timer iterrupt handler sets the decrementer to max so as
to avoid taking another decrementer interrupt when hard enabling
interrupts before running timers, it effectively disables the soft
NMI coverage for timer interrupts.

Fix this by using the traditional 31-bit value instead, which wraps
after a few seconds. masked interrupt code does the same thing, and
in normal operation neither of these paths would ever wrap even the
31 bit value.

Note: the SMP watchdog should catch timer interrupt lockups, but it
is preferable for the local soft-NMI to catch them, mainly to avoid
the IPI.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The broadcast tick recipient can call tick_receive_broadcast rather
than re-running the full timer interrupt.

It does not have to check for the next event time, because the sender
already determined the timer has expired. It does not have to test
irq_work_pending, because that's a direct decrementer interrupt and
does not go through the clock events subsystem. And it does not have
to read PURR because that was removed with the previous patch.

This results in no code size change, but both the decrementer and
broadcast path lengths are reduced.

Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

For SPLPAR, lparcfg provides a sum of PURR registers for all CPUs.
Currently this is done by reading PURR in context switch and timer
interrupt, and storing that into a per-CPU variable. These are summed
to provide the value.

This does not work with all timer schemes (e.g., NO_HZ_FULL), and it
is sub-optimal for performance because it reads the PURR register on
every context switch, although that's been difficult to distinguish
from noise in the contxt_switch microbenchmark.

This patch implements the sum by calling a function on each CPU, to
read and add PURR values of each CPU.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

These fields are only written to.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Book3S minimum supported ISA version now requires mtmsrd L=1. This
instruction does not require bits other than RI and EE to be supplied,
so __hard_irq_enable() and __hard_irq_disable() does not have to read
the kernel_msr from paca.

Interrupt entry code already relies on L=1 support.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This check does not catch IRQ soft mask bugs, but this option is
slightly more suitable than TRACE_IRQFLAGS.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

irq_work_raise should not cause a decrementer exception unless it is
called from NMI context. Doing so often just results in an immediate
masked decrementer interrupt:

   <...>-550    90d...    4us : update_curr_rt <-dequeue_task_rt
   <...>-550    90d...    5us : dbs_update_util_handler <-update_curr_rt
   <...>-550    90d...    6us : arch_irq_work_raise <-irq_work_queue
   <...>-550    90d...    7us : soft_nmi_interrupt <-soft_nmi_common
   <...>-550    90d...    7us : printk_nmi_enter <-soft_nmi_interrupt
   <...>-550    90d.Z.    8us : rcu_nmi_enter <-soft_nmi_interrupt
   <...>-550    90d.Z.    9us : rcu_nmi_exit <-soft_nmi_interrupt
   <...>-550    90d...    9us : printk_nmi_exit <-soft_nmi_interrupt
   <...>-550    90d...   10us : cpuacct_charge <-update_curr_rt

The soft_nmi_interrupt here is the call into the watchdog, due to the
decrementer interrupt firing with irqs soft-disabled. This is
harmless, but sub-optimal.

When it's not called from NMI context or with interrupts enabled, mark
the decrementer pending in the irq_happened mask directly, rather than
having the masked decrementer interupt handler do it. This will be
replayed at the next local_irq_enable. See the comment for details.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When IODA2 creates a PE, it creates an IOMMU table with it_ops::free
set to pnv_ioda2_table_free() which calls pnv_pci_ioda2_table_free_pages().

Since iommu_tce_table_put() calls it_ops::free when the last reference
to the table is released, explicit call to pnv_pci_ioda2_table_free_pages()
is not needed so let's remove it.

This should fix double free in the case of PCI hotuplug as
pnv_pci_ioda2_table_free_pages() does not reset neither
iommu_table::it_base nor ::it_size.

This was not exposed by SRIOV as it uses different code path via
pnv_pcibios_sriov_disable().

IODA1 does not inialize it_ops::free so it does not have this issue.

Fixes: c5f7700b ("powerpc/powernv: Dynamically release PE")
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

match_string() returns the index of an array for a matching string,
which can be used instead of open coded variant.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

GCC 8.1 emits warnings such as the following. As arch/powerpc code is
built with -Werror, this breaks the build with GCC 8.1.

  In file included from arch/powerpc/kernel/pci_64.c:23:
  ./include/linux/syscalls.h:233:18: error: 'sys_pciconfig_iobase' alias
  between functions of incompatible types 'long int(long int, long
  unsigned int, long unsigned int)' and 'long int(long int, long int,
  long int)' [-Werror=attribute-alias]
    asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
                    ^~~
  ./include/linux/syscalls.h:222:2: note: in expansion of macro '__SYSCALL_DEFINEx'
    __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)

This patch inhibits those warnings.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Trim change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

GCC 8.1 warns about possible string truncation:

  arch/powerpc/kernel/nvram_64.c:1042:2: error: 'strncpy' specified
  bound 12 equals destination size [-Werror=stringop-truncation]
    strncpy(new_part->header.name, name, 12);

  arch/powerpc/platforms/ps3/repository.c:106:2: error: 'strncpy'
  output truncated before terminating nul copying 8 bytes from a
  string of the same length [-Werror=stringop-truncation]
    strncpy((char *)&n, text, 8);

Fix it by using memcpy(). To make that safe we need to ensure the
destination is pre-zeroed. Use kzalloc() in the nvram code and
initialise the u64 to zero in the ps3 code.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Use kzalloc() in the nvram code, flesh out change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This is a branch with a mixture of mm, x86 and powerpc commits all
relating to some minor cross-arch pkeys consolidation. The x86/mm
changes have been reviewed by Ingo & Dave Hansen and the tree has been
in linux-next for some weeks without issue.

We ended up with an ugly conflict between fixes and next in ftrace.h
involving multiple nested ifdefs, and the automatic resolution is
wrong. So merge fixes into next so we can fix it up.

Merge in some commits we're sharing with the kbuild tree.

Merge in some commits we're sharing with the kvm-ppc tree.

Fix the below crash on Book3E 64. pgtable_page_dtor expects struct
page *arg.

Also call the destructor on non book3s platforms correctly. This frees
up the split PTL locks correctly if we had allocated them before.

Call Trace:
  .kmem_cache_free+0x9c/0x44c (unreliable)
  .ptlock_free+0x1c/0x30
  .tlb_remove_table+0xdc/0x224
  .free_pgd_range+0x298/0x500
  .shift_arg_pages+0x10c/0x1e0
  .setup_arg_pages+0x200/0x25c
  .load_elf_binary+0x450/0x16c8
  .search_binary_handler.part.11+0x9c/0x248
  .do_execveat_common.isra.13+0x868/0xc18
  .run_init_process+0x34/0x4c
  .try_to_run_init_process+0x1c/0x68
  .kernel_init+0xdc/0x130
  .ret_from_kernel_thread+0x58/0x7c

Fixes: 70234676 ("powerpc/mm/nohash: Remove pte fragment dependency from nohash")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

In commit eae5f709 ("powerpc: Add __printf verification to
prom_printf") __printf attribute was added to prom_printf(), which
means GCC started warning about type/format mismatches. As part of
that commit we changed some "%lx" formats to "%llx" where the type is
actually unsigned long long.

Unfortunately prom_printf() doesn't know how to print "%llx", it just
prints a literal "lx", eg:

  reserved memory map:
    lx - lx
    lx - lx

prom_printf() also doesn't know how to print "%u" (only "%lu"), it
just prints a literal "u", eg:

  Max number of cores passed to firmware: u (NR_CPUS = 2048)

Instead of:

  Max number of cores passed to firmware: 2048 (NR_CPUS = 2048)

This commit adds support for the missing formatters.

Fixes: eae5f709 ("powerpc: Add __printf verification to prom_printf")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

APC virtual machines arent used on POWER-9 chips and are already
disabled in on-chip CAPP. They also need to be disabled on the PSL via
'PSL Data Send Control Register' by setting bit(47). This forces the
PSL to send commands to CAPP with queue.id == 0.

Fixes: 56328743 ("cxl: Add support for POWER9 DD2")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Alastair D'Silva <alastair@d-silva.org>
Reviewed-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently we see a kernel-oops reported on Power-9 while attaching a
context to an AFU, with radix-mode and sysfs attr 'prefault_mode' set
to anything other than 'none'. The backtrace of the oops is of this
form:

  Unable to handle kernel paging request for data at address 0x00000080
  Faulting instruction address: 0xc00800000bcf3b20
  cpu 0x1: Vector: 300 (Data Access) at [c00000037f003800]
      pc: c00800000bcf3b20: cxl_load_segment+0x178/0x290 [cxl]
      lr: c00800000bcf39f0: cxl_load_segment+0x48/0x290 [cxl]
      sp: c00000037f003a80
     msr: 9000000000009033
     dar: 80
   dsisr: 40000000
    current = 0xc00000037f280000
    paca    = 0xc0000003ffffe600   softe: 3        irq_happened: 0x01
      pid   = 3529, comm = afp_no_int
  <snip>
  cxl_prefault+0xfc/0x248 [cxl]
  process_element_entry_psl9+0xd8/0x1a0 [cxl]
  cxl_attach_dedicated_process_psl9+0x44/0x130 [cxl]
  native_attach_process+0xc0/0x130 [cxl]
  afu_ioctl+0x3f4/0x5e0 [cxl]
  do_vfs_ioctl+0xdc/0x890
  ksys_ioctl+0x68/0xf0
  sys_ioctl+0x40/0xa0
  system_call+0x58/0x6c

The issue is caused as on Power-8 the AFU attr 'prefault_mode' was
used to improve initial storage fault performance by prefaulting
process segments. However on Power-9 with radix mode we don't have
Storage-Segments that we can prefault. Also prefaulting process Pages
will be too costly and fine-grained.

Hence, since the prefaulting mechanism doesn't makes sense of
radix-mode, this patch updates prefault_mode_store() to not allow any
other value apart from CXL_PREFAULT_NONE when radix mode is enabled.

Fixes: f24be42a ("cxl: Add psl9 specific code")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael 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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael 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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael 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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/stacktrace.c: In function ‘save_stack_trace_tsk_reliable’:
arch/powerpc/kernel/stacktrace.c:176:28: error: ‘kretprobe_trampoline’ undeclared
   if (ip == (unsigned long)kretprobe_trampoline)
                            ^~~~~~~~~~~~~~~~~~~~

Fixes: df78d3f6 ("powerpc/livepatch: Implement reliable stack tracing for the consistency model")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This test verifies that the AMR, IAMR and UAMOR are being written to a
process' core file.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
[mpe: Simplify make rule]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This test exercises read and write access to the AMR, IAMR and UAMOR.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
[mpe: Simplify make rule]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The toc field in the mod_arch_specific struct isn't actually used
anywhere, so remove it.

Also the ftrace-specific fields are now common between 32-bit and
64-bit, so simplify the struct definition a bit by moving them out of
the __powerpc64__ #ifdef.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Init all present cpus for deep states instead of "all possible" cpus.
Init fails if a possible cpu is guarded. Resulting in making only
non-deep states available for cpuidle/hotplug.

Stewart says, this means that for single threaded workloads, if you
guard out a CPU core you'll not get WoF (Workload Optimised
Frequency), which means that performance goes down when you wouldn't
expect it to.

Fixes: 77b54e9f ("powernv/powerpc: Add winkle support for offline cpus")
Cc: stable@vger.kernel.org # v3.19+
Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Comment explanning the raw event code encoding for Power8 was
moved to isa207_common.h file when re-factoring the code to
support power9. But then Power9 pmu branched out due to changes
specific to power9. So move the encoding comment back to power8-pmu.c
Just comment movement and no logic change.

Fixes: 4d3576b2 ('powerpc/perf: factor out power8 pmu macros and defines')
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The header file <asm/switch_to.h> was missing from the includes. Fix the
following warning, treated as error with W=1:

  arch/powerpc/kernel/vecemu.c:260:5: error: no previous prototype for ‘emulate_altivec’ [-Werror=missing-prototypes]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The header file <linux/syscalls.h> was missing from the includes. Fix the
following warning, treated as error with W=1:

  arch/powerpc/kernel/pci_32.c:286:6: error: no previous prototype for ‘sys_pciconfig_iobase’ [-Werror=missing-prototypes]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add a missing include <platforms/chrp/chrp.h>.

These functions can all be static, make it so. Fix warnings treated as
errors with W=1:

  arch/powerpc/platforms/chrp/time.c:41:13: error: no previous prototype for ‘chrp_time_init’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/chrp/time.c:66:5: error: no previous prototype for ‘chrp_cmos_clock_read’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/chrp/time.c:74:6: error: no previous prototype for ‘chrp_cmos_clock_write’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/chrp/time.c:86:5: error: no previous prototype for ‘chrp_set_rtc_time’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/chrp/time.c:130:6: error: no previous prototype for ‘chrp_get_rtc_time’ [-Werror=missing-prototypes]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

These functions can all be static, make it so. Fix warnings treated as
errors with W=1:

  arch/powerpc/kernel/tau_6xx.c:53:6: error: no previous prototype for ‘set_thresholds’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:73:6: error: no previous prototype for ‘TAUupdate’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:208:13: error: no previous prototype for ‘TAU_init_smp’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:220:12: error: no previous prototype for ‘TAU_init’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:126:6: error: no previous prototype for ‘TAUException’ [-Werror=missing-prototypes]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This function can be static, make it so, this fix a warning treated as
error with W=1:

  arch/powerpc/kernel/btext.c:173:5: error: no previous prototype for ‘btext_initialize’ [-Werror=missing-prototypes]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Some function prototypes and body for Thermal Assist Units were not in
sync. Update the function definition to match the existing function
declaration found in `setup-common.c`, changing an `int` return type to a
`u32` return type. Move the prototypes to a header file. Fix the following
warnings, treated as error with W=1:

  arch/powerpc/kernel/tau_6xx.c:257:5: error: no previous prototype for ‘cpu_temp_both’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:262:5: error: no previous prototype for ‘cpu_temp’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:267:5: error: no previous prototype for ‘tau_interrupts’ [-Werror=missing-prototypes]

Compile tested with CONFIG_TAU_INT.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add one missing prototype for function rh_dump_blk. Fix warning treated as
error in W=1:

  arch/powerpc/lib/rheap.c:740:6: error: no previous prototype for ‘rh_dump_blk’ [-Werror=missing-prototypes]
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The function prototypes were declared within a `#ifdef CONFIG_PPC_LITE5200`
block which would prevent them from being visible when compiling
`mpc52xx_pm.c`. Move the prototypes outside of the `#ifdef` block to fix
the following warnings treated as errors with W=1:

  arch/powerpc/platforms/52xx/mpc52xx_pm.c:58:5: error: no previous prototype for ‘mpc52xx_pm_prepare’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/52xx/mpc52xx_pm.c:113:5: error: no previous prototype for ‘mpc52xx_pm_enter’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/52xx/mpc52xx_pm.c:181:6: error: no previous prototype for ‘mpc52xx_pm_finish’ [-Werror=missing-prototypes]
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add a missing prototype for function `note_bootable_part` to silence a
warning treated as error with W=1:

  arch/powerpc/platforms/powermac/setup.c:361:12: error: no previous prototype for ‘note_bootable_part’ [-Werror=missing-prototypes]
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The pmac_pfunc_base_install prototype was declared in powermac/smp.c since
function was used there, move it to pmac_pfunc.h header to be visible in
pfunc_base.c. Fix a warning treated as error with W=1:

  arch/powerpc/platforms/powermac/pfunc_base.c:330:12: error: no previous prototype for ‘pmac_pfunc_base_install’ [-Werror=missing-prototypes]
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

These functions can all be static, make it so. Fix warnings treated as
errors with W=1:

  arch/powerpc/platforms/chrp/pci.c:34:5: error: no previous prototype for ‘gg2_read_config’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/chrp/pci.c:61:5: error: no previous prototype for ‘gg2_write_config’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/chrp/pci.c:97:5: error: no previous prototype for ‘rtas_read_config’ [-Werror=missing-prototypes]
  arch/powerpc/platforms/chrp/pci.c:112:5: error: no previous prototype for ‘rtas_write_config’ [-Werror=missing-prototypes]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Since the value of x is never intended to be read, declare it with gcc
attribute as unused. Fix warning treated as error with W=1:

  arch/powerpc/platforms/powermac/bootx_init.c:471:21: error: variable ‘x’ set but not used [-Werror=unused-but-set-variable]
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>