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>

The 8xx cannot access the TBL and TBU registers using mfspr/mtspr
It must be accessed using mftb/mftbu

Due to this, there is a number of places with #ifdef CONFIG_8xx

This patch defines new macros MFTBL(x) and MFTBU(x) on the same model
as MFTB(x) and tries to make use of them as much as possible.

In arch/powerpc/include/asm/timex.h, we also remove the ifdef
for the asm() operands as the compiler doesn't mind unused operands
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Since commit aa42c69c ("[POWERPC] Add support for FP emulation
for the e300c2 core"), program_check_exception() can be called for
math emulation. In that case, 'reason' is 0.

On the 8xx, there is a Software Emulation interrupt which is
called for all unimplemented and illegal instructions. This
interrupt calls SoftwareEmulation() which does almost the
same as program_check_exception() called with reason = 0.

The Software Emulation interrupt sets all reason bits to 0,
it is therefore possible to call program_check_exception()
directly from the interrupt handler.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

In the same spirit as what was done for 4xx and 44x, move
the 8xx machine check into platforms/8xx
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently we open code the reason codes for program checks. Instead use
the existing SRR1 defines.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We already have mce.c which is built for 64bit and contains other parts
of the machine check code, so move these bits in there too.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Make it clear that the fallback version of machine_check_generic() is
only used on 32-bit configs.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

get_mc_reason() no longer provides (if it ever really did) any
meaningful abstraction, so remove it.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Now that we have 4xx platform directory we can move the 4xx machine
check handler in there. Again we drop get_mc_reason() and replace it
with regs->dsisr directly (which is actually SPRN_ESR).
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We have several 44x machine check handlers defined in traps.c. It would
be preferable if they were split out with the platforms that use them.
Do that.

In the process, drop get_mc_reason() and instead just open code the
lookup of reason from regs->dsisr. This avoids a pointless layer of
abstraction.

We know to use regs->dsisr because 44x enables BOOKE which enables
PPC_ADV_DEBUG_REGS, and FSL_BOOKE is not enabled on 44x builds.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently we build the 47x cputable entries even when CONFIG_PPC_47x is
disabled. That means a kernel built without CONFIG_PPC_47x will claim to
support a 47x CPU and start booting, only to break somewhere later
because it doesn't have 47x support compiled in.

So guard the 47x cputable entries with CONFIG_PPC_47x. Note that this is
inside the #ifdef CONFIG_44x section, because 47x depends on 44x.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This adds an irq counter for the watchdog soft-NMI. This interrupt
only fires when interrupts are soft-disabled, so it will not
increment much even when the watchdog is running. However it's
useful for debugging and sanity checking.
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>

The powerpc kernel/watchdog.o should be built when HARDLOCKUP_DETECTOR
and HAVE_HARDLOCKUP_DETECTOR_ARCH are both selected. If only the former
is selected, then the generic perf watchdog has been selected.

To simplify this check, introduce a new Kconfig symbol PPC_WATCHDOG that
depends on both. This Kconfig option means the powerpc specific
watchdog is enabled.

Without this patch, Book3E will attempt to build the powerpc watchdog.

Fixes: 2104180a ("powerpc/64s: implement arch-specific hardlockup watchdog")
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

On 64-bit Book3s, when we're in HV mode, we have already counted the
machine check exception in machine_check_early().
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
[mpe: Use IS_ENABLED() rather than an #ifdef]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

binutils >= 2.26 now warns about misuse of register expressions in
assembler operands that are actually literals, for example:

  arch/powerpc/kernel/entry_64.S:535: Warning: invalid register expression

In practice these are almost all uses of r0 that should just be a
literal 0.
Signed-off-by: NAndreas Schwab <schwab@linux-m68k.org>
[mpe: Mention r0 is almost always the culprit, fold in purgatory change]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Commit d300627c ("powerpc/6xx: Handle DABR match before calling
do_page_fault") breaks non 6xx platforms.

  Failed to execute /init (error -14)
  Starting init: /bin/sh exists but couldn't execute it (error -14)
  Kernel panic - not syncing: No working init found.  Try passing init= ...
  CPU: 0 PID: 1 Comm: init Not tainted 4.13.0-rc3-s3k-dev-00143-g7aa62e972a56 #56
  Call Trace:
    panic+0x108/0x250 (unreliable)
    rootfs_mount+0x0/0x58
    ret_from_kernel_thread+0x5c/0x64
  Rebooting in 180 seconds..

This is because in handle_page_fault(), the call to do_page_fault() has been
mistakenly enclosed inside an #ifdef CONFIG_6xx

Fixes: d300627c ("powerpc/6xx: Handle DABR match before calling do_page_fault")
Brown-paper-bag-to-be-worn-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This uses the newly defined constants for this rather than open-coded
numbers. There is a side effect on 64-bit which is to pass through
some of the new P9 bits which we didn't before.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We test a number of bits from DSISR/SRR1 before deciding
to call hash_page(). If any of these is set, we go directly
to do_page_fault() as the bit indicate a fault that needs
to be handled there (no hashing needed).

This updates the current open-coded masks to use the new
DSISR definitions.

This *does* change the masks actually used in two ways:

 - We used to test various bits that were defined as "always 0"
in the architecture and could be repurposed for something
else. From now on, we just ignore such bits.

 - We were missing some new bits defined on P9
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

On legacy 6xx 32-bit procesors, we checked for the DABR match bit
in DSISR from do_page_fault(), in the middle of a pile of ifdef's
because all other CPU types do it in assembly prior to calling
do_page_fault. Fix that.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Add #ifdef CONFIG_6xx]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

By filtering the relevant SRR1 bits in the assembly rather than
in do_page_fault() itself, we avoid a conditional branch (since we
already come from different path for data and instruction faults).

This will allow more simplifications later
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Replace the __this_cpu_read() with raw_cpu_read() in
iommu_range_alloc(). Otherwise we get a warning about using
__this_cpu_read() in preemptible code:

  BUG: using __this_cpu_read() in preemptible
  caller is iommu_range_alloc+0xa8/0x3d0

Preemption doesn't need to be disabled since according to the comment
any CPU can safely use any IOMMU pool.
Signed-off-by: NVictor Aoqui <victora@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The stop4 idle state on POWER9 is a deep idle state which loses
hypervisor resources, but whose latency is low enough that it can be
exposed via cpuidle.

Until now, the deep idle states which lose hypervisor resources (eg:
winkle) were only exposed via CPU-Hotplug.  Hence currently on wakeup
from such states, barring a few SPRs which need to be restored to
their older value, rest of the SPRS are reinitialized to their values
corresponding to that at boot time.

When stop4 is used in the context of cpuidle, we want these additional
SPRs to be restored to their older value, to ensure that the context
on the CPU coming back from idle is same as it was before going idle.

In this patch, we define a SPR save area in PACA (since we have used
up the volatile register space in the stack) and on POWER9, we restore
SPRN_PID, SPRN_LDBAR, SPRN_FSCR, SPRN_HFSCR, SPRN_MMCRA, SPRN_MMCR1,
SPRN_MMCR2 to the values they had before entering stop.
Signed-off-by: NGautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

A previous optimisation incorrectly assumed the PAPR hcall does
not use r12, and clobbers it upon entry. In fact it is used as
an input. This can result in KVM guests crashing (observed with
PR KVM).

Instead of using r12 to save r13, tihs patch saves r13 in ctr.
This is more costly, but not as slow as using the SPRG.

Fixes: acd7d8ce ("powerpc/64s: Optimize hypercall/syscall entry")
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

POWER9 DD2 can see spurious PMU interrupts after state-loss idle in
some conditions.

A solution is to save and reload MMCR0 over state-loss idle.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Acked-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Tested-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

prom_init is a bit special; in theory it should be able to be linked
separately to the kernel.  To keep this from getting too complex, the
symbols that prom_init.c uses are checked.

Fortification adds symbols, and it gets quite messy as it includes
things like panic().  So just don't fortify prom_init.c for now.

Link: http://lkml.kernel.org/r/1497903987-21002-6-git-send-email-keescook@chromium.orgSigned-off-by: NDaniel Axtens <dja@axtens.net>
Signed-off-by: NKees Cook <keescook@chromium.org>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement an arch-speicfic watchdog rather than use the perf-based
hardlockup detector.

The new watchdog takes the soft-NMI directly, rather than going through
perf.  Perf interrupts are to be made maskable in future, so that would
prevent the perf detector from working in those regions.

Additionally, implement a SMP based detector where all CPUs watch one
another by pinging a shared cpumask.  This is because powerpc Book3S
does not have a true periodic local NMI, but some platforms do implement
a true NMI IPI.

If a CPU is stuck with interrupts hard disabled, the soft-NMI watchdog
does not work, but the SMP watchdog will.  Even on platforms without a
true NMI IPI to get a good trace from the stuck CPU, other CPUs will
notice the lockup sufficiently to report it and panic.

[npiggin@gmail.com: honor watchdog disable at boot/hotplug]
  Link: http://lkml.kernel.org/r/20170621001346.5bb337c9@roar.ozlabs.ibm.com
[npiggin@gmail.com: fix false positive warning at CPU unplug]
  Link: http://lkml.kernel.org/r/20170630080740.20766-1-npiggin@gmail.com
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170616065715.18390-6-npiggin@gmail.comSigned-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NDon Zickus <dzickus@redhat.com>
Tested-by: Babu Moger <babu.moger@oracle.com>	[sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split
HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR.

LOCKUP_DETECTOR implies the general boot, sysctl, and programming
interfaces for the lockup detectors.

An architecture that wants to use a hard lockup detector must define
HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH.

Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the
minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and
does not implement the LOCKUP_DETECTOR interfaces.

sparc is unusual in that it has started to implement some of the
interfaces, but not fully yet.  It should probably be converted to a full
HAVE_HARDLOCKUP_DETECTOR_ARCH.

[npiggin@gmail.com: fix]
  Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com
Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.comSigned-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NDon Zickus <dzickus@redhat.com>
Reviewed-by: NBabu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com>	[sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

vmcoreinfo_max_size stands for the vmcoreinfo_data, the correct one we
should use is vmcoreinfo_note whose total size is VMCOREINFO_NOTE_SIZE.

Like explained in commit 77019967 ("kdump: fix exported size of
vmcoreinfo note"), it should not affect the actual function, but we
better fix it, also this change should be safe and backward compatible.

After this, we can get rid of variable vmcoreinfo_max_size, let's use
the corresponding macros directly, fewer variables means more safety for
vmcoreinfo operation.

[xlpang@redhat.com: fix build warning]
  Link: http://lkml.kernel.org/r/1494830606-27736-1-git-send-email-xlpang@redhat.com
Link: http://lkml.kernel.org/r/1493281021-20737-2-git-send-email-xlpang@redhat.comSigned-off-by: NXunlei Pang <xlpang@redhat.com>
Reviewed-by: NMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reviewed-by: NDave Young <dyoung@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are two cases outside the normal address space management
where a CPU's local TLB is to be flushed:

  1. Host boot; in case something has left stale entries in the
     TLB (e.g., kexec).

  2. Machine check; to clean corrupted TLB entries.

CPU state restore from deep idle states also flushes the TLB.
However this seems to be a side effect of reusing the boot code to set
CPU state, rather than a requirement itself.

The current flushing has a number of problems with ISA v3.0B:

- The current radix mode of the MMU is not taken into account. tlbiel
  is undefined if the R field does not match the current radix mode.

- ISA v3.0B hash must flush the partition and process table caches.

- ISA v3.0B radix must flush partition and process scoped translations,
  partition and process table caches, and also the page walk cache.

Add POWER9 cases to handle these, with radix vs hash determined by the
host MMU mode.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This patch fixes a crash seen while doing a kexec from radix mode to
hash mode. Key 0 is special in hash and used in the RPN by default, we
set the key values to 0 today. In radix mode key 0 is used to control
supervisor<->user access. In hash key 0 is used by default, so the
first instruction after the switch causes a crash on kexec.

Commit 3b10d009 ("powerpc/mm/radix: Prevent kernel execution of
user space") introduced the setting of IAMR and AMOR values to prevent
execution of user mode instructions from supervisor mode. We need to
clean up these SPR's on kexec.

Fixes: 3b10d009 ("powerpc/mm/radix: Prevent kernel execution of user space")
Cc: stable@vger.kernel.org # v4.10+
Reported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NBalbir Singh <bsingharora@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Rename function_offset_within_entry() to scope it to kprobe namespace by
using kprobe_ prefix, and to also simplify it.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Suggested-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3aa6c7e2e4fb6e00f3c24fa306496a66edb558ea.1499443367.git.naveen.n.rao@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

For CONFIG_STRICT_KERNEL_RWX align __init_begin to 16M. We use 16M
since its the larger of 2M on radix and 16M on hash for our linear
mapping. The plan is to have .text, .rodata and everything upto
__init_begin marked as RX. Note we still have executable read only
data. We could further align rodata to another 16M boundary. I've used
keeping text plus rodata as read-only-executable as a trade-off to
doing read-only-executable for text and read-only for rodata.

We don't use multi PT_LOAD in PHDRS because we are not sure if all
bootloaders support them. This patch keeps PHDRS in vmlinux.lds.S as
the same they are with just one PT_LOAD for all of the kernel marked
as RWX (7).

mpe: What this means is the added alignment bloats the resulting
binary on disk, a powernv kernel goes from 17M to 22M.
Signed-off-by: NBalbir Singh <bsingharora@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

So that we can implement STRICT_RWX, use patch_instruction() in
optprobes.
Signed-off-by: NBalbir Singh <bsingharora@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch_arm/disarm_probe() use direct assignment for copying
instructions, replace them with patch_instruction(). We don't need to
call flush_icache_range() because patch_instruction() does it for us.
Signed-off-by: NBalbir Singh <bsingharora@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We can't take traps with relocation off, so blacklist enter_rtas() and
rtas_return_loc(). However, instead of blacklisting all of enter_rtas(),
introduce a new symbol __enter_rtas from where on we can't take a trap
and blacklist that.
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Blacklist all functions involved while handling a trap. We:
- convert some of the symbols into private symbols, and
- blacklist most functions involved while handling a trap.
Reviewed-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

It is actually safe to probe system_call() in entry_64.S, but only till
we unset MSR_RI. To allow this, add a new symbol system_call_exit()
after the mtmsrd and blacklist that.
Suggested-by: NMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

It is common to get a PMU interrupt right after the mtmsr instruction that
enables interrupts. Due to this, the stack trace profile gets needlessly split
across system_call_common() and system_call().

Previously, system_call() symbol was at the current place to hide a few
earlier symbols which have since been made private or removed entirely.

So, let's move system_call() slightly higher up, right after the mtmsr
instruction that enables interrupts. Convert existing references to
system_call to a local syscall symbol.
Suggested-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Convert some of the symbols into private symbols and blacklist
system_call_common() and system_call() from kprobes. We can't take a
trap at parts of these functions as either MSR_RI is unset or the
kernel stack pointer is not yet setup.
Reviewed-by: NMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Don't convert system_call_common to _GLOBAL()]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>