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
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
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>
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
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>
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>
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 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>
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
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>
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>
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>
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>
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>
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
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
.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>
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>
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>
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>
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>
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>
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>
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>
Use nmi_enter similarly to system reset interrupts. This uses NMI
printk NMI buffers and turns off various debugging facilities that
helps avoid tripping on ourselves or other CPUs.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
There are quite a few machine check exceptions that can be caused by
kernel bugs. To make debugging easier, use the kernel crash path in
cases of synchronous machine checks that occur in kernel mode, if that
would not result in the machine going straight to panic or crash dump.
There is a downside here that die()ing the process in kernel mode can
still leave the system unstable. panic_on_oops will always force the
system to fail-stop, so systems where that behaviour is important will
still do the right thing.
As a test, when triggering an i-side 0111b error (ifetch from foreign
address) in kernel mode process context on POWER9, the kernel currently
dies quickly like this:
Severe Machine check interrupt [Not recovered]
NIP [ffff000000000000]: 0xffff000000000000
Initiator: CPU
Error type: Real address [Instruction fetch (foreign)]
[ 127.426651616,0] OPAL: Reboot requested due to Platform error.
Effective[ 127.426693712,3] OPAL: Reboot requested due to Platform error. address: ffff000000000000
opal: Reboot type 1 not supported
Kernel panic - not syncing: PowerNV Unrecovered Machine Check
CPU: 56 PID: 4425 Comm: syscall Tainted: G M 4.12.0-rc1-13857-ga4700a261072-dirty #35
Call Trace:
[ 128.017988928,4] IPMI: BUG: Dropping ESEL on the floor due to
buggy/mising code in OPAL for this BMC
Rebooting in 10 seconds..
Trying to free IRQ 496 from IRQ context!
After this patch, the process is killed and the kernel continues with
this message, which gives enough information to identify the offending
branch (i.e., with CFAR):
Severe Machine check interrupt [Not recovered]
NIP [ffff000000000000]: 0xffff000000000000
Initiator: CPU
Error type: Real address [Instruction fetch (foreign)]
Effective address: ffff000000000000
Oops: Machine check, sig: 7 [#1]
SMP NR_CPUS=2048
NUMA
PowerNV
Modules linked in: iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 ...
CPU: 22 PID: 4436 Comm: syscall Tainted: G M 4.12.0-rc1-13857-ga4700a261072-dirty #36
task: c000000932300000 task.stack: c000000932380000
NIP: ffff000000000000 LR: 00000000217706a4 CTR: ffff000000000000
REGS: c00000000fc8fd80 TRAP: 0200 Tainted: G M (4.12.0-rc1-13857-ga4700a261072-dirty)
MSR: 90000000001c1003 <SF,HV,ME,RI,LE>
CR: 24000484 XER: 20000000
CFAR: c000000000004c80 DAR: 0000000021770a90 DSISR: 0a000000 SOFTE: 1
GPR00: 0000000000001ebe 00007fffce4818b0 0000000021797f00 0000000000000000
GPR04: 00007fff8007ac24 0000000044000484 0000000000004000 00007fff801405e8
GPR08: 900000000280f033 0000000024000484 0000000000000000 0000000000000030
GPR12: 9000000000001003 00007fff801bc370 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR28: 00007fff801b0000 0000000000000000 00000000217707a0 00007fffce481918
NIP [ffff000000000000] 0xffff000000000000
LR [00000000217706a4] 0x217706a4
Call Trace:
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
A system reset is a request to crash / debug the system rather than
necessarily caused by encountering a BUG. So there is no need to
serialize all CPUs behind the die lock, adding taints to all
subsequent traces beyond the first, breaking console locks, etc.
The system reset is NMI context which has its own printk buffers to
prevent output being interleaved. Then it's better to have all
secondaries print out their debug as quickly as possible and the
primary will flush out all printk buffers during panic().
So remove the 0x100 path from die, and move it into system_reset. Name
the crash/dump reasons "System Reset".
This gives "not tained" traces when crashing an untainted kernel. It
also gives the panic reason as "System Reset" as opposed to "Fatal
exception in interrupt" (or "die oops" for fadump).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
If fadump is not registered, and no other crash or debug handlers are
registered, the powerpc panic handler stops the guest before the
generic panic code can push out debug information to the console.
Currently, system reset injection causes the guest to silently stop.
Stop calling ppc_md.panic in the panic notifier. crash_fadump already
does rtas_os_term() to terminate the guest if fadump is registered.
Remove ppc_md.panic. Move fadump panic notifier into fadump code.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This fixes a couple more bits of fallout from the new hard lockup watchdog
patch.
It restores the required hw_nmi_get_sample_period() function for the
perf watchdog, and removes some function declarations on 64e that are only
defined for 64s. This fixes the 64e build when the hardlockup detector is
enabled.
It restores the default behaviour of disabling the perf watchdog, and also
fixes disabling the 64s watchdog when running as a guest.
Fixes: 2104180a53 ("powerpc/64s: implement arch-specific hardlockup watchdog")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Linus Torvalds