Commit Graph

6340 Commits

Author SHA1 Message Date
Naveen N. Rao
bf3a912517 powerpc/kprobes: Clean up jprobe detection in livepatch handler
In commit c05b8c4474 ("powerpc/kprobes: Skip livepatch_handler() for
jprobes"), we added a helper is_current_kprobe_addr() to help detect if
the modified regs->nip was due to a jprobe or livepatch. Masami felt
that the function name was not quite clear. To that end, this patch
renames is_current_kprobe_addr() to __is_active_jprobe() and adds a
comment to (hopefully) better clarify the purpose of this helper. The
helper has also now been moved to kprobes-ftrace.c so that it is only
available for KPROBES_ON_FTRACE.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 23:42:17 +11:00
Naveen N. Rao
a7b440383f powerpc/kprobes: Do not suppress instruction emulation if a single run failed
Currently, we disable instruction emulation if emulate_step() fails for
any reason. However, such failures could be transient and specific to a
particular run. Instead, only disable instruction emulation if we have
never been able to emulate this. If we had emulated this instruction
successfully at least once, then we single step only this probe hit and
continue to try emulating the instruction in subsequent probe hits.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 23:42:16 +11:00
Naveen N. Rao
22085337f5 powerpc/kprobes: Some cosmetic updates to try_to_emulate()
1. This is only used in kprobes.c, so make it static.
2. Remove the un-necessary (ret == 0) comparison in the else clause.

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 23:42:12 +11:00
Thomas Gleixner
34ddaa3e5c powerpc/watchdog: Make use of watchdog_nmi_probe()
The rework of the core hotplug code triggers the WARN_ON in start_wd_cpu()
on powerpc because it is called multiple times for the boot CPU.

The first call is via:

  start_wd_on_cpu+0x80/0x2f0
  watchdog_nmi_reconfigure+0x124/0x170
  softlockup_reconfigure_threads+0x110/0x130
  lockup_detector_init+0xbc/0xe0
  kernel_init_freeable+0x18c/0x37c
  kernel_init+0x2c/0x160
  ret_from_kernel_thread+0x5c/0xbc

And then again via the CPU hotplug registration:

  start_wd_on_cpu+0x80/0x2f0
  cpuhp_invoke_callback+0x194/0x620
  cpuhp_thread_fun+0x7c/0x1b0
  smpboot_thread_fn+0x290/0x2a0
  kthread+0x168/0x1b0
  ret_from_kernel_thread+0x5c/0xbc

This can be avoided by setting up the cpu hotplug state with nocalls and
move the initialization to the watchdog_nmi_probe() function. That
initializes the hotplug callbacks without invoking the callback and the
following core initialization function then configures the watchdog for the
online CPUs (in this case CPU0) via softlockup_reconfigure_threads().

Reported-and-tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
2017-10-04 10:53:54 +02:00
Thomas Gleixner
e31d6883f2 watchdog/core, powerpc: Lock cpus across reconfiguration
Instead of dropping the cpu hotplug lock after stopping NMI watchdog and
threads and reaquiring for restart, the code and the protection rules
become more obvious when holding cpu hotplug lock across the full
reconfiguration.

Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710022105570.2114@nanos
2017-10-04 10:53:54 +02:00
Thomas Gleixner
6b9dc4806b watchdog/core, powerpc: Replace watchdog_nmi_reconfigure()
The recent cleanup of the watchdog code split watchdog_nmi_reconfigure()
into two stages. One to stop the NMI and one to restart it after
reconfiguration. That was done by adding a boolean 'run' argument to the
code, which is functionally correct but not necessarily a piece of art.

Replace it by two explicit functions: watchdog_nmi_stop() and
watchdog_nmi_start().

Fixes: 6592ad2fcc ("watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage")
Requested-by: Linus 'Nursing his pet-peeve' Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Thomas 'Mopping up garbage' Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710021957480.2114@nanos
2017-10-04 10:53:53 +02:00
Allen Pais
8d6b1bf20f powerpc/6xx: Use setup_timer() helper
Use setup_timer function instead of initializing timer with the
function and data fields.

Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:28:02 +11:00
Nicholas Piggin
969a86a285 powerpc/powernv: Use early_radix_enabled in POWER9 tlb flush
This code is used at boot and machine checks, so it should be using
early_radix_enabled() (which is usable any time).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:28:01 +11:00
Nicholas Piggin
78adf6c214 powerpc/64s: Implement system reset idle wakeup reason
It is possible to wake from idle due to a system reset exception, in
which case the CPU takes a system reset interrupt to wake from idle,
with system reset as the wakeup reason.

The regular (not idle wakeup) system reset interrupt handler must be
invoked in this case, otherwise the system reset interrupt is lost.

Handle the system reset interrupt immediately after CPU state has been
restored.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:26:32 +11:00
Nicholas Piggin
80e4d70b06 powerpc/watchdog: Do not trigger SMP crash from touch_nmi_watchdog
In xmon, touch_nmi_watchdog() is not expected to be checking that
other CPUs have not touched the watchdog, so the code will just call
touch_nmi_watchdog() once before re-enabling hard interrupts.

Just update our CPU's state, and ignore apparently stuck SMP threads.

Arguably touch_nmi_watchdog should check for SMP lockups, and callers
should be fixed, but that's not trivial for the input code of xmon.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:26:02 +11:00
Nicholas Piggin
d58fdd9d7f powerpc/watchdog: Do not backtrace locked CPUs twice if allcpus backtrace is enabled
If sysctl_hardlockup_all_cpu_backtrace is enabled, there is no need to
IPI stuck CPUs for backtrace before trigger_allbutself_cpu_backtrace(),
which does the same thing again.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:25:50 +11:00
Nicholas Piggin
842dc1dbab powerpc/watchdog: Do not panic from locked CPU's IPI handler
The SMP watchdog will detect locked CPUs and IPI them to print a
backtrace and registers. If panic on hard lockup is enabled, do not
panic from this handler, because that can cause recursion into the IPI
layer during the panic.

The caller already panics in this case.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:25:40 +11:00
Christian Lamparter
070e004912 powerpc/4xx: Fix compile error with 64K pages on 40x, 44x
The mmu context on the 40x, 44x does not define pte_frag entry. This
causes gcc abort the compilation due to:

  setup-common.c: In function ‘setup_arch’:
  setup-common.c:908: error: ‘mm_context_t’ has no ‘pte_frag’

This patch fixes the issue by removing the pte_frag initialization in
setup-common.c.

This is possible, because the compiler will do the initialization,
since the mm_context is a sub struct of init_mm. init_mm is declared
in mm_types.h as external linkage.

According to C99 6.2.4.3:
  An object whose identifier is declared with external linkage
  [...] has static storage duration.

C99 defines in 6.7.8.10 that:
  If an object that has static storage duration is not
  initialized explicitly, then:
  - if it has pointer type, it is initialized to a null pointer

Fixes: b1923caa6e ("powerpc: Merge 32-bit and 64-bit setup_arch()")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-03 21:59:48 +11:00
Jeremy Kerr
3b7af5c0fd powerpc: Fix action argument for cpufeatures-based TLB flush
Commit 41d0c2ecde ("powerpc/powernv: Fix local TLB flush for boot
and MCE on POWER9") introduced calls to __flush_tlb_power[89] from the
cpufeatures code, specifying the number of sets to flush.

However, these functions take an action argument, not a number of
sets. This means we hit the BUG() in __flush_tlb_{206,300} when using
cpufeatures-style configuration.

This change passes TLB_INVAL_SCOPE_GLOBAL instead.

Fixes: 41d0c2ecde ("powerpc/powernv: Fix local TLB flush for boot and MCE on POWER9")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-03 16:16:55 +11:00
Michael Neuling
bca73f595a powerpc: Fix workaround for spurious MCE on POWER9
In the recent commit d8bd9f3f09 ("powerpc: Handle MCE on POWER9 with
only DSISR bit 30 set") I screwed up the bit number. It should be bit
25 (IBM bit 38).

Fixes: d8bd9f3f09 ("powerpc: Handle MCE on POWER9 with only DSISR bit 30 set")
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-29 14:19:44 +10:00
Michael Neuling
5080332c2c powerpc/64s: Add workaround for P9 vector CI load issue
POWER9 DD2.1 and earlier has an issue where some cache inhibited
vector load will return bad data. The workaround is two part, one
firmware/microcode part triggers HMI interrupts when hitting such
loads, the other part is this patch which then emulates the
instructions in Linux.

The affected instructions are limited to lxvd2x, lxvw4x, lxvb16x and
lxvh8x.

When an instruction triggers the HMI, all threads in the core will be
sent to the HMI handler, not just the one running the vector load.

In general, these spurious HMIs are detected by the emulation code and
we just return back to the running process. Unfortunately, if a
spurious interrupt occurs on a vector load that's to normal memory we
have no way to detect that it's spurious (unless we walk the page
tables, which is very expensive). In this case we emulate the load but
we need do so using a vector load itself to ensure 128bit atomicity is
preserved.

Some additional debugfs emulated instruction counters are added also.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Switch CONFIG_PPC_BOOK3S_64 to CONFIG_VSX to unbreak the build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-27 08:23:22 +10:00
Michael Neuling
d8bd9f3f09 powerpc: Handle MCE on POWER9 with only DSISR bit 30 set
On POWER9 DD2.1 and below, it's possible for a paste instruction to
cause a Machine Check Exception (MCE) where only DSISR bit 30 (IBM 33)
is set. This will result in the MCE handler seeing an unknown event,
which triggers linux to crash.

We change this by detecting unknown events caused by load/stores in
the MCE handler and marking them as handled so that we no longer
crash.

An MCE that occurs like this is spurious, so we don't need to do
anything in terms of servicing it. If there is something that needs to
be serviced, the CPU will raise the MCE again with the correct DSISR
so that it can be serviced properly.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com
Acked-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Expand comment with details from change log, use normal bit #s]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-26 21:01:59 +10:00
Benjamin Herrenschmidt
b9fde58db7 powerpc/powernv: Rework EEH initialization on powernv
Remove the post_init callback which is only used
by powernv, we can just call it explicitly from
the powernv code.

This partially kills the ability to "disable" eeh at
runtime via debugfs as this was calling that same
callback again, but this is both unused and broken
in several ways. If we want to revive it, we need
to create a dedicated enable/disable callback on the
backend that does the right thing.

Let the bulk of eeh initialize normally at
core_initcall() like it does on pseries by removing
the hack in eeh_init() that delays it.

Instead we make sure our eeh->probe cleanly bails
out of the PEs haven't been created yet and we force
a re-probe where we used to call eeh_init() again.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-26 11:19:07 +10:00
Benjamin Herrenschmidt
3e77adeea3 powerpc/eeh: Create PHB PEs after EEH is initialized
Otherwise we end up not yet having computed the right diag data size
on powernv where EEH initialization is delayed, thus causing memory
corruption later on when calling OPAL.

Fixes: 5cb1f8fddd ("powerpc/powernv/pci: Dynamically allocate PHB diag data")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-21 14:56:00 +10:00
Naveen N. Rao
8afafa6fba powerpc/kprobes: Update optprobes to use emulate_update_regs()
Optprobes depended on an updated regs->nip from analyse_instr() to
identify the location to branch back from the optprobes trampoline.
However, since commit 3cdfcbfd32 ("powerpc: Change analyse_instr so
it doesn't modify *regs"), analyse_instr() doesn't update the registers
anymore.  Due to this, we end up branching back from the optprobes
trampoline to the same branch into the trampoline resulting in a loop.

Fix this by calling out to emulate_update_regs() before using the nip.
Additionally, explicitly compare the return value from analyse_instr()
to 1, rather than just checking for !0 so as to guard against any
future changes to analyse_instr() that may result in -1 being returned
in more scenarios.

Fixes: 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-20 20:21:24 +10:00
Michael Ellerman
b134165ead Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into fixes
Merge one commit from Scott which I missed while away.
2017-09-20 20:05:24 +10:00
Gustavo Romero
c1fa0768a8 powerpc/tm: Flush TM only if CPU has TM feature
Commit cd63f3c ("powerpc/tm: Fix saving of TM SPRs in core dump")
added code to access TM SPRs in flush_tmregs_to_thread(). However
flush_tmregs_to_thread() does not check if TM feature is available on
CPU before trying to access TM SPRs in order to copy live state to
thread structures. flush_tmregs_to_thread() is indeed guarded by
CONFIG_PPC_TRANSACTIONAL_MEM but it might be the case that kernel
was compiled with CONFIG_PPC_TRANSACTIONAL_MEM enabled and ran on
a CPU without TM feature available, thus rendering the execution
of TM instructions that are treated by the CPU as illegal instructions.

The fix is just to add proper checking in flush_tmregs_to_thread()
if CPU has the TM feature before accessing any TM-specific resource,
returning immediately if TM is no available on the CPU. Adding
that checking in flush_tmregs_to_thread() instead of in places
where it is called, like in vsr_get() and vsr_set(), is better because
avoids the same problem cropping up elsewhere.

Cc: stable@vger.kernel.org # v4.13+
Fixes: cd63f3c ("powerpc/tm: Fix saving of TM SPRs in core dump")
Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-20 13:30:09 +10:00
Al Viro
a5ae754a3d ppc: switch to {get,put}_compat_sigset()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-09-19 17:56:03 -04:00
Linus Torvalds
418702b910 Merge tag 'powerpc-4.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fix from Michael Ellerman:
 "Just one fix, for the handling of alignment interrupts on dcbz
  instructions.

  Thanks to Paul Mackerras, Christian Zigotzky, Michal Sojka"

* tag 'powerpc-4.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc: Fix handling of alignment interrupt on dcbz instruction
2017-09-15 12:44:59 -07:00
Paul Mackerras
1bc944cee6 powerpc: Fix handling of alignment interrupt on dcbz instruction
This fixes the emulation of the dcbz instruction in the alignment
interrupt handler.  The error was that we were comparing just the
instruction type field of op.type rather than the whole thing,
and therefore the comparison "type != CACHEOP + DCBZ" was always
true.

Fixes: 31bfdb036f ("powerpc: Use instruction emulation infrastructure to handle alignment faults")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Tested-by: Michal Sojka <sojkam1@fel.cvut.cz>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-15 08:41:18 +10:00
Thomas Gleixner
ab5fe3ff38 watchdog/hardlockup: Clean up hotplug locking mess
All watchdog thread related functions are delegated to the smpboot thread
infrastructure, which handles serialization against CPU hotplug correctly.

The sysctl interface is completely decoupled from anything which requires
CPU hotplug protection.

No need to protect the sysctl writes against cpu hotplug anymore. Remove it
and add the now required protection to the powerpc arch_nmi_watchdog
implementation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20170912194148.418497420@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14 11:41:09 +02:00
Thomas Gleixner
6592ad2fcc watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage
Both the perf reconfiguration and the powerpc watchdog_nmi_reconfigure()
need to be done in two steps.

     1) Stop all NMIs
     2) Read the new parameters and start NMIs

Right now watchdog_nmi_reconfigure() is a combination of both. To allow a
clean reconfiguration add a 'run' argument and split the functionality in
powerpc.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20170912194147.862865570@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14 11:41:07 +02:00
Thomas Gleixner
5490125d77 watchdog/core: Remove broken suspend/resume interfaces
This interface has several issues:

 - It's causing recursive locking of the hotplug lock.

 - It's complete overkill to teardown all threads and then recreate them

The same can be achieved with the simple hardlockup_detector_perf_stop /
restart() interfaces. The abuse from the busy looping poweroff() loop of
PARISC has been solved as well.

Remove the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194146.487537732@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14 11:41:04 +02:00
Michal Hocko
0ee931c4e3 mm: treewide: remove GFP_TEMPORARY allocation flag
GFP_TEMPORARY was introduced by commit e12ba74d8f ("Group short-lived
and reclaimable kernel allocations") along with __GFP_RECLAIMABLE.  It's
primary motivation was to allow users to tell that an allocation is
short lived and so the allocator can try to place such allocations close
together and prevent long term fragmentation.  As much as this sounds
like a reasonable semantic it becomes much less clear when to use the
highlevel GFP_TEMPORARY allocation flag.  How long is temporary? Can the
context holding that memory sleep? Can it take locks? It seems there is
no good answer for those questions.

The current implementation of GFP_TEMPORARY is basically GFP_KERNEL |
__GFP_RECLAIMABLE which in itself is tricky because basically none of
the existing caller provide a way to reclaim the allocated memory.  So
this is rather misleading and hard to evaluate for any benefits.

I have checked some random users and none of them has added the flag
with a specific justification.  I suspect most of them just copied from
other existing users and others just thought it might be a good idea to
use without any measuring.  This suggests that GFP_TEMPORARY just
motivates for cargo cult usage without any reasoning.

I believe that our gfp flags are quite complex already and especially
those with highlevel semantic should be clearly defined to prevent from
confusion and abuse.  Therefore I propose dropping GFP_TEMPORARY and
replace all existing users to simply use GFP_KERNEL.  Please note that
SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and
so they will be placed properly for memory fragmentation prevention.

I can see reasons we might want some gfp flag to reflect shorterm
allocations but I propose starting from a clear semantic definition and
only then add users with proper justification.

This was been brought up before LSF this year by Matthew [1] and it
turned out that GFP_TEMPORARY really doesn't have a clear semantic.  It
seems to be a heuristic without any measured advantage for most (if not
all) its current users.  The follow up discussion has revealed that
opinions on what might be temporary allocation differ a lot between
developers.  So rather than trying to tweak existing users into a
semantic which they haven't expected I propose to simply remove the flag
and start from scratch if we really need a semantic for short term
allocations.

[1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org

[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: drm/i915: fix up]
  Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-13 18:53:16 -07:00
Linus Torvalds
dd198ce714 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman:
 "Life has been busy and I have not gotten half as much done this round
  as I would have liked. I delayed it so that a minor conflict
  resolution with the mips tree could spend a little time in linux-next
  before I sent this pull request.

  This includes two long delayed user namespace changes from Kirill
  Tkhai. It also includes a very useful change from Serge Hallyn that
  allows the security capability attribute to be used inside of user
  namespaces. The practical effect of this is people can now untar
  tarballs and install rpms in user namespaces. It had been suggested to
  generalize this and encode some of the namespace information
  information in the xattr name. Upon close inspection that makes the
  things that should be hard easy and the things that should be easy
  more expensive.

  Then there is my bugfix/cleanup for signal injection that removes the
  magic encoding of the siginfo union member from the kernel internal
  si_code. The mips folks reported the case where I had used FPE_FIXME
  me is impossible so I have remove FPE_FIXME from mips, while at the
  same time including a return statement in that case to keep gcc from
  complaining about unitialized variables.

  I almost finished the work to get make copy_siginfo_to_user a trivial
  copy to user. The code is available at:

     git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git neuter-copy_siginfo_to_user-v3

  But I did not have time/energy to get the code posted and reviewed
  before the merge window opened.

  I was able to see that the security excuse for just copying fields
  that we know are initialized doesn't work in practice there are buggy
  initializations that don't initialize the proper fields in siginfo. So
  we still sometimes copy unitialized data to userspace"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  Introduce v3 namespaced file capabilities
  mips/signal: In force_fcr31_sig return in the impossible case
  signal: Remove kernel interal si_code magic
  fcntl: Don't use ambiguous SIG_POLL si_codes
  prctl: Allow local CAP_SYS_ADMIN changing exe_file
  security: Use user_namespace::level to avoid redundant iterations in cap_capable()
  userns,pidns: Verify the userns for new pid namespaces
  signal/testing: Don't look for __SI_FAULT in userspace
  signal/mips: Document a conflict with SI_USER with SIGFPE
  signal/sparc: Document a conflict with SI_USER with SIGFPE
  signal/ia64: Document a conflict with SI_USER with SIGFPE
  signal/alpha: Document a conflict with SI_USER for SIGTRAP
2017-09-11 18:34:47 -07:00
Alexey Dobriyan
9b130ad5bb treewide: make "nr_cpu_ids" unsigned
First, number of CPUs can't be negative number.

Second, different signnnedness leads to suboptimal code in the following
cases:

1)
	kmalloc(nr_cpu_ids * sizeof(X));

"int" has to be sign extended to size_t.

2)
	while (loff_t *pos < nr_cpu_ids)

MOVSXD is 1 byte longed than the same MOV.

Other cases exist as well. Basically compiler is told that nr_cpu_ids
can't be negative which can't be deduced if it is "int".

Code savings on allyesconfig kernel: -3KB

	add/remove: 0/0 grow/shrink: 25/264 up/down: 261/-3631 (-3370)
	function                                     old     new   delta
	coretemp_cpu_online                          450     512     +62
	rcu_init_one                                1234    1272     +38
	pci_device_probe                             374     399     +25

				...

	pgdat_reclaimable_pages                      628     556     -72
	select_fallback_rq                           446     369     -77
	task_numa_find_cpu                          1923    1807    -116

Link: http://lkml.kernel.org/r/20170819114959.GA30580@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:48 -07:00
Cédric Le Goater
ac5e5a5402 powerpc/xive: add XIVE Exploitation Mode to CAS
On POWER9, the Client Architecture Support (CAS) negotiation process
determines whether the guest operates in XIVE Legacy compatibility or
in XIVE exploitation mode. Now that we have initial guest support for
the XIVE interrupt controller, let's inform the hypervisor what we can
do.

The platform advertises the XIVE Exploitation Mode support using the
property "ibm,arch-vec-5-platform-support-vec-5", byte 23 bits 0-1 :

 - 0b00 XIVE legacy mode Only
 - 0b01 XIVE exploitation mode Only
 - 0b10 XIVE legacy or exploitation mode

The OS asks for XIVE Exploitation Mode support using the property
"ibm,architecture-vec-5", byte 23 bits 0-1:

 - 0b00 XIVE legacy mode Only
 - 0b01 XIVE exploitation mode Only

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-02 21:02:38 +10:00
Julia Lawall
8a7aef2cb3 powerpc/iommu: Use permission-specific DEVICE_ATTR variants
Use DEVICE_ATTR_RW for read-write attributes.  This simplifies the
source code, improves readbility, and reduces the chance of
inconsistencies.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:42:54 +10:00
Markus Elfring
6ab41161b4 powerpc/eeh: Delete an error out of memory message at init time
Omit an extra message for a memory allocation failure in
eeh_dev_init().

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[mpe: Do not drop the message that can happen at runtime and lead to
 an event not being handled]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:42:53 +10:00
Christophe Leroy
ad1b0122bd powerpc/32: remove a NOP from memset()
memset() is patched after initialisation to activate the
optimised part which uses cache instructions.

Today we have a 'b 2f' to skip the optimised patch, which then gets
replaced by a NOP, implying a useless cycle consumption.
As we have a 'bne 2f' just before, we could use that instruction
for the live patching, hence removing the need to have a
dedicated 'b 2f' to be replaced by a NOP.

This patch changes the 'bne 2f' by a 'b 2f'. During init, that
'b 2f' is then replaced by 'bne 2f'

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:42:46 +10:00
Paul Mackerras
31bfdb036f powerpc: Use instruction emulation infrastructure to handle alignment faults
This replaces almost all of the instruction emulation code in
fix_alignment() with calls to analyse_instr(), emulate_loadstore()
and emulate_dcbz().  The only emulation code left is the SPE
emulation code; analyse_instr() etc. do not handle SPE instructions
at present.

One result of this is that we can now handle alignment faults on
all the new VSX load and store instructions that were added in POWER9.
VSX loads/stores will take alignment faults for unaligned accesses
to cache-inhibited memory.

Another effect is that we no longer rely on the DAR and DSISR values
set by the processor.

With this, we now need to include the instruction emulation code
unconditionally.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:42:43 +10:00
Michael Ellerman
f9effe9250 powerpc: Fix DAR reporting when alignment handler faults
Anton noticed that if we fault part way through emulating an unaligned
instruction, we don't update the DAR to reflect that.

The DAR value is eventually reported back to userspace as the address
in the SEGV signal, and if userspace is using that value to demand
fault then it can be confused by us not setting the value correctly.

This patch is ugly as hell, but is intended to be the minimal fix and
back ports easily.

Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 22:06:57 +10:00
Oliver O'Halloran
96d91431d6 powerpc/smp: Add Power9 scheduler topology
In previous generations of Power processors each core had a private L2
cache. The Power 9 processor has a slightly different design where the
L2 cache is shared among pairs of cores rather than being completely
private.

Making the scheduler aware of this cache sharing allows the scheduler to
make better migration decisions. For example, if two CPU heavy tasks
share a core then one task can be migrated to the paired core to improve
throughput. Under the existing three level topology the task could be
migrated to any core on the same chip, while with the new topology it
would be preferentially migrated to the paired core so it remains
cache-hot.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 18:16:08 +10:00
Oliver O'Halloran
2a636a56d2 powerpc/smp: Add cpu_l2_cache_map
We want to add an extra level to the CPU scheduler topology to account
for cores which share a cache. To do this we need to build a cpumask
for each CPU that indicates which CPUs share this cache to use as an
input to the scheduler.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:56 +10:00
Oliver O'Halloran
df52f67140 powerpc/smp: Rework CPU topology construction
The CPU scheduler topology is constructed from a number of per-cpu
cpumasks which describe which sets of logical CPUs are related in some
fashion. Current code that handles constructing these masks when CPUs
are hot(un)plugged can be simplified a bit by exploiting the fact that
the scheduler requires higher levels of the toplogy (e.g package level
groupings) to be supersets of the lower levels (e.g.  threas in a core).
This patch reworks the cpumask construction to be simpler and easier to
extend with extra topology levels.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Fix CONFIG_HOTPLUG_CPU=n build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:51 +10:00
Oliver O'Halloran
e3d8b67e2c powerpc/smp: Use cpu_to_chip_id() to find core siblings
When building the CPU scheduler topology the kernel uses the ibm,chipid
property from the devicetree to group logical CPUs. Currently the DT
search for this property is open-coded in smp.c and this functionality
is a duplication of what's in cpu_to_chip_id() already. This patch
removes the existing search in favor of that.

It's worth mentioning that the semantics of the search are different
in cpu_to_chip_id(). When there is no ibm,chipid in the CPUs node it
will also search /cpus and / for the property, but this should not
effect the output topology.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:50 +10:00
Tobin C. Harding
eb039161da powerpc/asm: Convert .llong directives to .8byte
.llong is an undocumented PPC specific directive. The generic
equivalent is .quad, but even better (because it's self describing) is
.8byte.

Convert all .llong directives to .8byte.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:47 +10:00
Masahiro Yamada
7f2462acb6 powerpc: Squash lines for simple wrapper functions
Remove unneeded variables and assignments.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:42 +10:00
Bryant G. Ly
f9df74dfce powerpc/kernel: Change retrieval of pci_dn
For a PCI device it's pci_dn can be retrieved from
pdev->dev.archdata.firmware_data, PCI_DN(devnode), or parent's list.
Thus, we should just use the existing function pci_get_pdn_by_devfn
to get the pci_dn.

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Reviewed-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:40 +10:00
Alexey Kardashevskiy
f1e08232ed powerpc/pci: Remove OF node back pointer from pci_dn
The check_req() helper uses pci_get_pdn() to get an OF node pointer.
pci_get_pdn() returns a pci_dn pointer which either:
1) from the OF node returned by pci_device_to_OF_node();
2) from the parent child_list where entries don't have OF node pointers.
Since check_req() does not care about 2), it can call
pci_device_to_OF_node() directly, hence the change.

The find_pe_dn() helper uses embedded pci_dn to get an OF node which is
also stored in edev->pdev so let's take a shortcut and call
pci_device_to_OF_node() directly.

With these 2 changes, we can finally get rid of the OF node back pointer.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:12 +10:00
Alexey Kardashevskiy
14db3d52d3 powerpc/eeh: Reduce use of pci_dn::node
The pci_dn struct caches a OF device node pointer in order to access
the "ibm,loc-code" property when EEH is recovering.

However, when this happens in eeh_dev_check_failure(), we also have
a pci_dev pointer which should have a valid pointer to the device node
when pci_dn has one (both pointers are not NULL for physical functions
and are NULL for virtual functions).

This changes pci_remove_device_node_info() to look for a parent of
the node being removed, just like pci_add_device_node_info() does when it
references the parent node.

This is the first step to get rid of pci_dn::node.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:10 +10:00
Alexey Kardashevskiy
405b33a76d powerpc/eeh: Remove unnecessary config_addr from eeh_dev
The eeh_dev struct hold a config space address of an associated node
and the very same address is also stored in the pci_dn struct which
is always present during the eeh_dev lifetime.

This uses bus:devfn directly from pci_dn instead of cached and packed
config_addr.

Since config_addr is made from device's bus:dev.fn, there is no point
in keeping it in the debugfs either so remove that too.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:09 +10:00
Alexey Kardashevskiy
69672bd748 powerpc/eeh: Remove unnecessary pointer to phb from eeh_dev
The eeh_dev struct already holds a pointer to pci_dn which it does not
exist without and pci_dn itself holds the very same pointer so just
use it.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:09 +10:00
Alexey Kardashevskiy
8bae6a2319 powerpc/eeh: Reduce to one the number of places where edev is allocated
arch/powerpc/kernel/eeh_dev.c:57 is the only legit place where edev
is allocated; other 2 places allocate it on stack and in the heap for
a very short period of time to use eeh_pe_get() as takes edev.

This changes eeh_pe_get() to receive required parameters explicitly.

This removes unnecessary temporary allocation of edev.

This uses the "pe_no" name instead of the "pe_config_addr" name as
it actually is a PE number and not a config space address as it seemed.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:08 +10:00
Alexey Kardashevskiy
5f600b17d1 powerpc/pci: Remove unused parameter from add_one_dev_pci_data()
pdev is always NULL, remove it.

To make checkpatch.pl happy, this also removes the "out of memory"
message.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-31 14:26:07 +10:00