On POWER9 systems, we push the VCPU context onto the XIVE (eXternal
Interrupt Virtualization Engine) hardware when entering a guest,
and pull the context off the XIVE when exiting the guest. The push
is done with cache-inhibited stores, and the pull with cache-inhibited
loads.
Testing has revealed that it is possible (though very rare) for
the stores to get reordered with the loads so that we end up with the
guest VCPU context still loaded on the XIVE after we have exited the
guest. When that happens, it is possible for the same VCPU context
to then get loaded on another CPU, which causes the machine to
checkstop.
To fix this, we add I/O barrier instructions (eieio) before and
after the push and pull operations. As partial compensation for the
potential slowdown caused by the extra barriers, we remove the eieio
instructions between the two stores in the push operation, and between
the two loads in the pull operation. (The architecture requires
loads to cache-inhibited, guarded storage to be kept in order, and
requires stores to cache-inhibited, guarded storage likewise to be
kept in order, but allows such loads and stores to be reordered with
respect to each other.)
Reported-by: Carol L Soto <clsoto@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
kvmppc_gpa_to_ua() accesses KVM memory slot array via
srcu_dereference_check() and this produces warnings from RCU like below.
This extends the existing srcu_read_lock/unlock to cover that
kvmppc_gpa_to_ua() as well.
We did not hit this before as this lock is not needed for the realmode
handlers and hash guests would use the realmode path all the time;
however the radix guests are always redirected to the virtual mode
handlers and hence the warning.
[ 68.253798] ./include/linux/kvm_host.h:575 suspicious rcu_dereference_check() usage!
[ 68.253799]
other info that might help us debug this:
[ 68.253802]
rcu_scheduler_active = 2, debug_locks = 1
[ 68.253804] 1 lock held by qemu-system-ppc/6413:
[ 68.253806] #0: (&vcpu->mutex){+.+.}, at: [<c00800000e3c22f4>] vcpu_load+0x3c/0xc0 [kvm]
[ 68.253826]
stack backtrace:
[ 68.253830] CPU: 92 PID: 6413 Comm: qemu-system-ppc Tainted: G W 4.14.0-rc3-00553-g432dcba58e9c-dirty #72
[ 68.253833] Call Trace:
[ 68.253839] [c000000fd3d9f790] [c000000000b7fcc8] dump_stack+0xe8/0x160 (unreliable)
[ 68.253845] [c000000fd3d9f7d0] [c0000000001924c0] lockdep_rcu_suspicious+0x110/0x180
[ 68.253851] [c000000fd3d9f850] [c0000000000e825c] kvmppc_gpa_to_ua+0x26c/0x2b0
[ 68.253858] [c000000fd3d9f8b0] [c00800000e3e1984] kvmppc_h_put_tce+0x12c/0x2a0 [kvm]
Fixes: 121f80ba68 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
- Add another case where msgsync is required.
- Required barrier sequence for global doorbells is msgsync ; lwsync
When msgsnd is used for IPIs to other cores, msgsync must be executed by
the target to order stores performed on the source before its msgsnd
(provided the source executes the appropriate sync).
Fixes: 1704a81cce ("KVM: PPC: Book3S HV: Use msgsnd for IPIs to other cores on POWER9")
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The following program causes a kernel oops:
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/kvm.h>
main()
{
int fd = open("/dev/kvm", O_RDWR);
ioctl(fd, KVM_CHECK_EXTENSION, KVM_CAP_PPC_HTM);
}
This happens because when using the global KVM fd with
KVM_CHECK_EXTENSION, kvm_vm_ioctl_check_extension() gets
called with a NULL kvm argument, which gets dereferenced
in is_kvmppc_hv_enabled(). Spotted while reading the code.
Let's use the hv_enabled fallback variable, like everywhere
else in this function.
Fixes: 23528bb21e ("KVM: PPC: Introduce KVM_CAP_PPC_HTM")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
A fix for a bad bug (written by me) in our livepatch handler. Removal of an
over-zealous lockdep_assert_cpus_held() in our topology code. A fix to the
recently added emulation of cntlz[wd]. And three small fixes to the recently
added IMC PMU driver.
Thanks to:
Anju T Sudhakar, Balbir Singh, Kamalesh Babulal, Naveen N. Rao, Sandipan Das,
Santosh Sivaraj, Thiago Jung Bauermann.
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Merge tag 'powerpc-4.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"A fix for a bad bug (written by me) in our livepatch handler. Removal
of an over-zealous lockdep_assert_cpus_held() in our topology code. A
fix to the recently added emulation of cntlz[wd]. And three small
fixes to the recently added IMC PMU driver.
Thanks to: Anju T Sudhakar, Balbir Singh, Kamalesh Babulal, Naveen N.
Rao, Sandipan Das, Santosh Sivaraj, Thiago Jung Bauermann"
* tag 'powerpc-4.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/perf: Fix IMC initialization crash
powerpc/perf: Add ___GFP_NOWARN flag to alloc_pages_node()
powerpc/perf: Fix for core/nest imc call trace on cpuhotplug
powerpc: Don't call lockdep_assert_cpus_held() from arch_update_cpu_topology()
powerpc/lib/sstep: Fix count leading zeros instructions
powerpc/livepatch: Fix livepatch stack access
Panic observed with latest firmware, and upstream kernel:
NIP init_imc_pmu+0x8c/0xcf0
LR init_imc_pmu+0x2f8/0xcf0
Call Trace:
init_imc_pmu+0x2c8/0xcf0 (unreliable)
opal_imc_counters_probe+0x300/0x400
platform_drv_probe+0x64/0x110
driver_probe_device+0x3d8/0x580
__driver_attach+0x14c/0x1a0
bus_for_each_dev+0x8c/0xf0
driver_attach+0x34/0x50
bus_add_driver+0x298/0x350
driver_register+0x9c/0x180
__platform_driver_register+0x5c/0x70
opal_imc_driver_init+0x2c/0x40
do_one_initcall+0x64/0x1d0
kernel_init_freeable+0x280/0x374
kernel_init+0x24/0x160
ret_from_kernel_thread+0x5c/0x74
While registering nest imc at init, cpu-hotplug callback
nest_pmu_cpumask_init() makes an OPAL call to stop the engine. And if
the OPAL call fails, imc_common_cpuhp_mem_free() is invoked to cleanup
memory and cpuhotplug setup.
But when cleaning up the attribute group, we are dereferencing the
attribute element array without checking whether the backing element
is not NULL. This causes the kernel panic.
Add a check for the backing element prior to dereferencing the
attribute element, to handle the failing case gracefully.
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Reported-by: Pridhiviraj Paidipeddi <ppaidipe@linux.vnet.ibm.com>
[mpe: Trim change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nest/core pmu units are enabled only when it is used. A reference count is
maintained for the events which uses the nest/core pmu units. Currently in
*_imc_counters_release function a WARN() is used for notification of any
underflow of ref count.
The case where event ref count hit a negative value is, when perf session is
started, followed by offlining of all cpus in a given core.
i.e. in cpuhotplug offline path ppc_core_imc_cpu_offline() function set the
ref->count to zero, if the current cpu which is about to offline is the last
cpu in a given core and make an OPAL call to disable the engine in that core.
And on perf session termination, perf->destroy (core_imc_counters_release) will
first decrement the ref->count for this core and based on the ref->count value
an opal call is made to disable the core-imc engine.
Now, since cpuhotplug path already clears the ref->count for core and disabled
the engine, perf->destroy() decrementing again at event termination make it
negative which in turn fires the WARN_ON. The same happens for nest units.
Add a check to see if the reference count is alreday zero, before decrementing
the count, so that the ref count will not hit a negative value.
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Reviewed-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
It turns out that not all paths calling arch_update_cpu_topology() hold
cpu_hotplug_lock, but that's OK because those paths can't race with
any concurrent hotplug events.
Warnings were reported with the following trace:
lockdep_assert_cpus_held
arch_update_cpu_topology
sched_init_domains
sched_init_smp
kernel_init_freeable
kernel_init
ret_from_kernel_thread
Which is safe because it's called early in boot when hotplug is not
live yet.
And also this trace:
lockdep_assert_cpus_held
arch_update_cpu_topology
partition_sched_domains
cpuset_update_active_cpus
sched_cpu_deactivate
cpuhp_invoke_callback
cpuhp_down_callbacks
cpuhp_thread_fun
smpboot_thread_fn
kthread
ret_from_kernel_thread
Which is safe because it's called as part of CPU hotplug, so although
we don't hold the CPU hotplug lock, there is another thread driving
the CPU hotplug operation which does hold the lock, and there is no
race.
Thanks to tglx for deciphering it for us.
Fixes: 3e401f7a2e ("powerpc: Only obtain cpu_hotplug_lock if called by rtasd")
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
According to the GCC documentation, the behaviour of __builtin_clz()
and __builtin_clzl() is undefined if the value of the input argument
is zero. Without handling this special case, these builtins have been
used for emulating the following instructions:
* Count Leading Zeros Word (cntlzw[.])
* Count Leading Zeros Doubleword (cntlzd[.])
This fixes the emulated behaviour of these instructions by adding an
additional check for this special case.
Fixes: 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
While running stress test with livepatch module loaded, kernel bug was
triggered.
cpu 0x5: Vector: 400 (Instruction Access) at [c0000000eb9d3b60]
5:mon> t
[c0000000eb9d3de0] c0000000eb9d3e30 (unreliable)
[c0000000eb9d3e30] c000000000008ab4 hardware_interrupt_common+0x114/0x120
--- Exception: 501 (Hardware Interrupt) at c000000000053040 livepatch_handler+0x4c/0x74
[c0000000eb9d4120] 0000000057ac6e9d (unreliable)
[d0000000089d9f78] 2e0965747962382e
SP (965747962342e09) is in userspace
When an interrupt occurs during the livepatch_handler execution, it's
possible for the livepatch_stack and/or thread_info to be corrupted.
eg:
Task A Interrupt Handler
========= =================
livepatch_handler:
mr r0, r1
ld r1, TI_livepatch_sp(r12)
hardware_interrupt_common:
do_IRQ+0x8:
mflr r0 <- saved stack pointer is overwritten
bl _mcount
...
std r27,-40(r1) <- overwrite of thread_info()
lis r2, STACK_END_MAGIC@h
ori r2, r2, STACK_END_MAGIC@l
ld r12, -8(r1)
Fix the corruption by using r11 register for livepatch stack
manipulation, instead of shuffling task stack and livepatch stack into
r1 register. Using r11 register also avoids disabling/enabling irq's
while setting up the livepatch stack.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Merge powerpc transactional memory fixes from Michael Ellerman:
"I figured I'd still send you the commits using a bundle to make sure
it works in case I need to do it again in future"
This fixes transactional memory state restore for powerpc.
* bundle'd patches from Michael Ellerman:
powerpc/tm: Fix illegal TM state in signal handler
powerpc/64s: Use emergency stack for kernel TM Bad Thing program checks
- fix PPC XIVE interrupt delivery
- fix x86 RCU breakage from asynchronous page faults when built without
PREEMPT_COUNT
- fix x86 build with -frecord-gcc-switches
- fix x86 build without X86_LOCAL_APIC
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Radim Krčmář:
- fix PPC XIVE interrupt delivery
- fix x86 RCU breakage from asynchronous page faults when built without
PREEMPT_COUNT
- fix x86 build with -frecord-gcc-switches
- fix x86 build without X86_LOCAL_APIC
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: add X86_LOCAL_APIC dependency
x86/kvm: Move kvm_fastop_exception to .fixup section
kvm/x86: Avoid async PF preempting the kernel incorrectly
KVM: PPC: Book3S: Fix server always zero from kvmppc_xive_get_xive()
Nine small fixes, really nothing that stands out.
A work around for a spurious MCE on Power9. A CXL fault handling fix, some fixes
to the new XIVE code, and a fix to the new 32-bit STRICT_KERNEL_RWX code.
Fixes for old code/stable: an fix to an incorrect TLB flush on boot but not on
any current machines, a compile error on 4xx and a fix to memory hotplug when
using radix (Power9).
Thanks to:
Anton Blanchard, Cédric Le Goater, Christian Lamparter, Christophe Leroy,
Christophe Lombard, Guenter Roeck, Jeremy Kerr, Michael Neuling, Nicholas
Piggin.
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Merge tag 'powerpc-4.14-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"Nine small fixes, really nothing that stands out.
A work-around for a spurious MCE on Power9. A CXL fault handling fix,
some fixes to the new XIVE code, and a fix to the new 32-bit
STRICT_KERNEL_RWX code.
Fixes for old code/stable: an fix to an incorrect TLB flush on boot
but not on any current machines, a compile error on 4xx and a fix to
memory hotplug when using radix (Power9).
Thanks to: Anton Blanchard, Cédric Le Goater, Christian Lamparter,
Christophe Leroy, Christophe Lombard, Guenter Roeck, Jeremy Kerr,
Michael Neuling, Nicholas Piggin"
* tag 'powerpc-4.14-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/powernv: Increase memory block size to 1GB on radix
powerpc/mm: Call flush_tlb_kernel_range with interrupts enabled
powerpc/xive: Clear XIVE internal structures when a CPU is removed
powerpc/xive: Fix IPI reset
powerpc/4xx: Fix compile error with 64K pages on 40x, 44x
powerpc: Fix action argument for cpufeatures-based TLB flush
cxl: Fix memory page not handled
powerpc: Fix workaround for spurious MCE on POWER9
powerpc: Handle MCE on POWER9 with only DSISR bit 30 set
Pull watchddog clean-up and fixes from Thomas Gleixner:
"The watchdog (hard/softlockup detector) code is pretty much broken in
its current state. The patch series addresses this by removing all
duct tape and refactoring it into a workable state.
The reasons why I ask for inclusion that late in the cycle are:
1) The code causes lockdep splats vs. hotplug locking which get
reported over and over. Unfortunately there is no easy fix.
2) The risk of breakage is minimal because it's already broken
3) As 4.14 is a long term stable kernel, I prefer to have working
watchdog code in that and the lockdep issues resolved. I wouldn't
ask you to pull if 4.14 wouldn't be a LTS kernel or if the
solution would be easy to backport.
4) The series was around before the merge window opened, but then got
delayed due to the UP failure caused by the for_each_cpu()
surprise which we discussed recently.
Changes vs. V1:
- Addressed your review points
- Addressed the warning in the powerpc code which was discovered late
- Changed two function names which made sense up to a certain point
in the series. Now they match what they do in the end.
- Fixed a 'unused variable' warning, which got not detected by the
intel robot. I triggered it when trying all possible related config
combinations manually. Randconfig testing seems not random enough.
The changes have been tested by and reviewed by Don Zickus and tested
and acked by Micheal Ellerman for powerpc"
* 'core-watchdog-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
watchdog/core: Put softlockup_threads_initialized under ifdef guard
watchdog/core: Rename some softlockup_* functions
powerpc/watchdog: Make use of watchdog_nmi_probe()
watchdog/core, powerpc: Lock cpus across reconfiguration
watchdog/core, powerpc: Replace watchdog_nmi_reconfigure()
watchdog/hardlockup/perf: Fix spelling mistake: "permanetely" -> "permanently"
watchdog/hardlockup/perf: Cure UP damage
watchdog/hardlockup: Clean up hotplug locking mess
watchdog/hardlockup/perf: Simplify deferred event destroy
watchdog/hardlockup/perf: Use new perf CPU enable mechanism
watchdog/hardlockup/perf: Implement CPU enable replacement
watchdog/hardlockup/perf: Implement init time detection of perf
watchdog/hardlockup/perf: Implement init time perf validation
watchdog/core: Get rid of the racy update loop
watchdog/core, powerpc: Make watchdog_nmi_reconfigure() two stage
watchdog/sysctl: Clean up sysctl variable name space
watchdog/sysctl: Get rid of the #ifdeffery
watchdog/core: Clean up header mess
watchdog/core: Further simplify sysctl handling
watchdog/core: Get rid of the thread teardown/setup dance
...
Currently it's possible that on returning from the signal handler
through the restore_tm_sigcontexts() code path (e.g. from a signal
caught due to a `trap` instruction executed in the middle of an HTM
block, or a deliberately constructed sigframe) an illegal TM state
(like TS=10 TM=0, i.e. "T0") is set in SRR1 and when `rfid` sets
implicitly the MSR register from SRR1 register on return to userspace
it causes a TM Bad Thing exception.
That illegal state can be set (a) by a malicious user that disables
the TM bit by tweaking the bits in uc_mcontext before returning from
the signal handler or (b) by a sufficient number of context switches
occurring such that the load_tm counter overflows and TM is disabled
whilst in the signal handler.
This commit fixes the illegal TM state by ensuring that TM bit is
always enabled before we return from restore_tm_sigcontexts(). A small
comment correction is made as well.
Fixes: 5d176f751e ("powerpc: tm: Enable transactional memory (TM) lazily for userspace")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When using transactional memory (TM), the CPU can be in one of six
states as far as TM is concerned, encoded in the Machine State
Register (MSR). Certain state transitions are illegal and if attempted
trigger a "TM Bad Thing" type program check exception.
If we ever hit one of these exceptions it's treated as a bug, ie. we
oops, and kill the process and/or panic, depending on configuration.
One case where we can trigger a TM Bad Thing, is when returning to
userspace after a system call or interrupt, using RFID. When this
happens the CPU first restores the user register state, in particular
r1 (the stack pointer) and then attempts to update the MSR. However
the MSR update is not allowed and so we take the program check with
the user register state, but the kernel MSR.
This tricks the exception entry code into thinking we have a bad
kernel stack pointer, because the MSR says we're coming from the
kernel, but r1 is pointing to userspace.
To avoid this we instead always switch to the emergency stack if we
take a TM Bad Thing from the kernel. That way none of the user
register values are used, other than for printing in the oops message.
This is the fix for CVE-2017-1000255.
Fixes: 5d176f751e ("powerpc: tm: Enable transactional memory (TM) lazily for userspace")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
[mpe: Rewrite change log & comments, tweak asm slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Memory hot unplug on PowerNV radix hosts is broken. Our memory block
size is 256MB but since we map the linear region with very large
pages, each pte we tear down maps 1GB.
A hot unplug of one 256MB memory block results in 768MB of memory
getting unintentionally unmapped. At this point we are likely to oops.
Fix this by increasing our memory block size to 1GB on PowerNV radix
hosts.
Fixes: 4b5d62ca17 ("powerpc/mm: add radix__remove_section_mapping()")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit eac1e731b5 ("powerpc/xive: guest exploitation of the XIVE
interrupt controller") introduced support for the XIVE exploitation
mode of the P9 interrupt controller on the pseries platform.
At that time, support for CPU removal was not complete on PowerVM and
CPU hot unplug remained untested. It appears that some cleanups of the
XIVE internal structures are required before releasing the CPU,
without which the kernel crashes in a RTAS call doing the CPU
isolation.
These changes fix the crash by deconfiguring the IPI interrupt source
and clearing the event queues of the CPU when it is removed.
Fixes: eac1e731b5 ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When resetting an IPI, hw_ipi should also be set to zero.
Fixes: eac1e731b5 ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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
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
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
Locking of config and doorbell operations should be done only if the
underlying hardware requires it.
This patch removes the global spinlocks from the rapidio subsystem and
moves them to the mport drivers (fsl_rio and tsi721), only to the
necessary places. For example, local config space read and write
operations (lcread/lcwrite) are atomic in all existing drivers, so there
should be no need for locking, while the cread/cwrite operations which
generate maintenance transactions need to be synchronized with a lock.
Later, each driver could chose to use a per-port lock instead of a
global one, or even more granular locking.
Link: http://lkml.kernel.org/r/20170824113023.GD50104@nokia.com
Signed-off-by: Ioan Nicu <ioan.nicu.ext@nokia.com>
Signed-off-by: Frank Kunz <frank.kunz@nokia.com>
Acked-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In KVM's XICS-on-XIVE emulation, kvmppc_xive_get_xive() returns the
value of state->guest_server as "server". However, this value is not
set by it's counterpart kvmppc_xive_set_xive(). When the guest uses
this interface to migrate interrupts away from a CPU that is going
offline, it sees all interrupts as belonging to CPU 0, so they are
left assigned to (now) offline CPUs.
This patch removes the guest_server field from the state, and returns
act_server in it's place (that is, the CPU actually handling the
interrupt, which may differ from the one requested).
Fixes: 5af5099385 ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Cc: stable@vger.kernel.org
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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>
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>
that was finally triggered by PCID support.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"Mixed bugfixes. Perhaps the most interesting one is a latent bug that
was finally triggered by PCID support"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
kvm/x86: Handle async PF in RCU read-side critical sections
KVM: nVMX: Fix nested #PF intends to break L1's vmlauch/vmresume
KVM: VMX: use cmpxchg64
KVM: VMX: simplify and fix vmx_vcpu_pi_load
KVM: VMX: avoid double list add with VT-d posted interrupts
KVM: VMX: extract __pi_post_block
KVM: PPC: Book3S HV: Check for updated HDSISR on P9 HDSI exception
KVM: nVMX: fix HOST_CR3/HOST_CR4 cache
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>
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>
On POWER9 DD2.1 and below, sometimes on a Hypervisor Data Storage
Interrupt (HDSI) the HDSISR is not be updated at all.
To work around this we put a canary value into the HDSISR before
returning to a guest and then check for this canary when we take a
HDSI. If we find the canary on a HDSI, we know the hardware didn't
update the HDSISR. In this case we return to the guest to retake the
HDSI which should correctly update the HDSISR the second time HDSI
entry.
After talking to Paulus we've applied this workaround to all POWER9
CPUs. The workaround of returning to the guest shouldn't ever be
triggered on well behaving CPU. The extra instructions should have
negligible performance impact.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A reference to the parent device node is held by add_dt_node() for the
node to be added. If the call to dlpar_configure_connector() fails
add_dt_node() returns ENOENT and that reference is not freed.
Add a call to of_node_put(parent_dn) prior to bailing out after a
failed dlpar_configure_connector() call.
Fixes: 8d5ff32076 ("powerpc/pseries: Make dlpar_configure_connector parent node aware")
Cc: stable@vger.kernel.org # v3.12+
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit 215ee763f8 ("powerpc: pseries: remove dlpar_attach_node
dependency on full path") reworked dlpar_attach_node() to no longer
look up the parent node "/cpus", but instead to have the parent node
passed by the caller in the function parameter list.
As a result dlpar_attach_node() is no longer responsible for freeing
the reference to the parent node. However, commit 215ee763f8 failed
to remove the of_node_put(parent) call in dlpar_attach_node(), or to
take into account that the reference to the parent in the caller
dlpar_cpu_add() needs to be held until after dlpar_attach_node()
returns.
As a result doing repeated cpu add/remove dlpar operations will
eventually result in the following error:
OF: ERROR: Bad of_node_put() on /cpus
CPU: 0 PID: 10896 Comm: drmgr Not tainted 4.13.0-autotest #1
Call Trace:
dump_stack+0x15c/0x1f8 (unreliable)
of_node_release+0x1a4/0x1c0
kobject_put+0x1a8/0x310
kobject_del+0xbc/0xf0
__of_detach_node_sysfs+0x144/0x210
of_detach_node+0xf0/0x180
dlpar_detach_node+0xc4/0x120
dlpar_cpu_remove+0x280/0x560
dlpar_cpu_release+0xbc/0x1b0
arch_cpu_release+0x6c/0xb0
cpu_release_store+0xa0/0x100
dev_attr_store+0x68/0xa0
sysfs_kf_write+0xa8/0xf0
kernfs_fop_write+0x2cc/0x400
__vfs_write+0x5c/0x340
vfs_write+0x1a8/0x3d0
SyS_write+0xa8/0x1a0
system_call+0x58/0x6c
Fix the issue by removing the of_node_put(parent) call from
dlpar_attach_node(), and ensuring that the reference to the parent
node is properly held and released by the caller dlpar_cpu_add().
Fixes: 215ee763f8 ("powerpc: pseries: remove dlpar_attach_node dependency on full path")
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
[mpe: Add a comment in the code and frob the change log slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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>
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>
Commit 24be85a23d ("powerpc/powernv: Clear PECE1 in LPCR via
stop-api only on Hotplug") clears the PECE1 bit of the LPCR via
stop-api during CPU-Hotplug to prevent wakeup due to a decrementer on
an offlined CPU which is in a deep stop state.
In the case where the stop-api support is found to be lacking, the
commit 785a12afdb ("powerpc/powernv/idle: Disable LOSE_FULL_CONTEXT
states when stop-api fails") disables deep states that lose hypervisor
context. Thus in this case, the offlined CPU will be put to some
shallow idle state.
However, we currently unconditionally clear the PECE1 in LPCR via
stop-api during CPU-Hotplug even when deep states are disabled due to
stop-api failure.
Fix this by clearing PECE1 of LPCR via stop-api during CPU-Hotplug
*only* when the offlined CPU will be put to a deep state that loses
hypervisor context.
Fixes: 24be85a23d ("powerpc/powernv: Clear PECE1 in LPCR via stop-api only on Hotplug")
Reported-by: Pavithra Prakash <pavirampu@linux.vnet.ibm.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Pavithra Prakash <pavrampu@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
mullw should do a 32 bit signed multiply and create a 64 bit signed
result. It currently truncates the result to 32 bits.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
mcrf broke when we changed analyse_instr() to not modify the register
state. The instruction writes to the CR, so we need to store the result
in op->ccval, not op->val.
Fixes: 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
set_cr0() broke when we changed analyse_instr() to not modify the
register state. Instead of looking at regs->gpr[x] which has not
been updated yet, we need to look at op->val.
Fixes: 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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>
Kernel crashes if power pmu is not registered and user tries to dump
regs with 'echo p > /proc/sysrq-trigger'. Sample log:
Unable to handle kernel paging request for data at address 0x00000008
Faulting instruction address: 0xc0000000000d52f0
NIP [c0000000000d52f0] perf_event_print_debug+0x10/0x230
LR [c00000000058a938] sysrq_handle_showregs+0x38/0x50
Call Trace:
printk+0x38/0x4c (unreliable)
__handle_sysrq+0xe4/0x270
write_sysrq_trigger+0x64/0x80
proc_reg_write+0x80/0xd0
__vfs_write+0x40/0x200
vfs_write+0xc8/0x240
SyS_write+0x60/0x110
system_call+0x58/0x6c
Fixes: 5f6d0380c6 ("powerpc/perf: Define perf_event_print_debug() to print PMU register values")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit eb3b705aae ("ALSA: Make CONFIG_SND_OSSEMUL user-selectable")
means we need to set CONFIG_SND_OSSEMUL in our configs, otherwise we
lose some of the SND symbols.
And commit 0181307abc ("ALSA: seq: Reorganize kconfig and build")
reorganised things, which causes the churn.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Just one fix, for the handling of alignment interrupts on dcbz instructions.
Thanks to:
Paul Mackerras, Christian Zigotzky, Michal Sojka.
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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
Particularly because kvmppc_fast_vcpu_kick_hv() is a callback,
ensure that we properly serialize wq active checks in order to
avoid potentially missing a wakeup due to racing with the waiter
side.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
Radim Krčmář