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These fields are only written to.
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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PR KVM will need to reuse msr_check_and_set().
This patch exports this API for reuse.
Signed-off-by: Simon Guo <[email protected]>
Reviewed-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.
Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.
The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.
In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.
Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.
Signed-off-by: "Eric W. Biederman" <[email protected]>
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flush_thread() calls __set_breakpoint() via set_debug_reg_defaults()
without checking ppc_breakpoint_available(). On Power8 or later CPUs
which have the DAWR feature disabled that will cause a write to the
DABR which is incorrect as those CPUs don't have a DABR.
Fix it two ways, by checking ppc_breakpoint_available() in
set_debug_reg_defaults(), and also by reworking __set_breakpoint() to
only write to DABR on Power7 or earlier.
Fixes: 9654153158d3 ("powerpc: Disable DAWR in the base POWER9 CPU features")
Signed-off-by: Nicholas Piggin <[email protected]>
[mpe: Rework the logic in __set_breakpoint()]
Signed-off-by: Michael Ellerman <[email protected]>
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Merge the DAWR series, which touches arch code and KVM code and may need
to be merged into the kvm-ppc tree.
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Add ppc_breakpoint_available() to determine if a breakpoint is
available currently via the DAWR or DABR.
Signed-off-by: Michael Neuling <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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__giveup_fpu() is never called outside process.c, so it can be static.
That also means we don't need an empty definition in switch_to.h
Signed-off-by: Mathieu Malaterre <[email protected]>
[mpe: Also drop the empty version, rewrite change log]
Signed-off-by: Michael Ellerman <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Highlights:
- Enable support for memory protection keys aka "pkeys" on Power7/8/9
when using the hash table MMU.
- Extend our interrupt soft masking to support masking PMU interrupts
as well as "normal" interrupts, and then use that to implement
local_t for a ~4x speedup vs the current atomics-based
implementation.
- A new driver "ocxl" for "Open Coherent Accelerator Processor
Interface (OpenCAPI)" devices.
- Support for new device tree properties on PowerVM to describe
hotpluggable memory and devices.
- Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE to the 64-bit
VDSO.
- Freescale updates from Scott: fixes for CPM GPIO and an FSL PCI
erratum workaround, plus a minor cleanup patch.
As well as quite a lot of other changes all over the place, and small
fixes and cleanups as always.
Thanks to: Alan Modra, Alastair D'Silva, Alexey Kardashevskiy,
Alistair Popple, Andreas Schwab, Andrew Donnellan, Aneesh Kumar K.V,
Anju T Sudhakar, Anshuman Khandual, Anton Blanchard, Arnd Bergmann,
Balbir Singh, Benjamin Herrenschmidt, Bhaktipriya Shridhar, Bryant G.
Ly, Cédric Le Goater, Christophe Leroy, Christophe Lombard, Cyril Bur,
David Gibson, Desnes A. Nunes do Rosario, Dmitry Torokhov, Frederic
Barrat, Geert Uytterhoeven, Guilherme G. Piccoli, Gustavo A. R. Silva,
Gustavo Romero, Ivan Mikhaylov, Joakim Tjernlund, Joe Perches, Josh
Poimboeuf, Juan J. Alvarez, Julia Cartwright, Kamalesh Babulal,
Madhavan Srinivasan, Mahesh Salgaonkar, Mathieu Malaterre, Michael
Bringmann, Michael Hanselmann, Michael Neuling, Nathan Fontenot,
Naveen N. Rao, Nicholas Piggin, Paul Mackerras, Philippe Bergheaud,
Ram Pai, Russell Currey, Santosh Sivaraj, Scott Wood, Seth Forshee,
Simon Guo, Stewart Smith, Sukadev Bhattiprolu, Thiago Jung Bauermann,
Vaibhav Jain, Vasyl Gomonovych"
* tag 'powerpc-4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (199 commits)
powerpc/mm/radix: Fix build error when RADIX_MMU=n
macintosh/ams-input: Use true and false for boolean values
macintosh: change some data types from int to bool
powerpc/watchdog: Print the NIP in soft_nmi_interrupt()
powerpc/watchdog: regs can't be null in soft_nmi_interrupt()
powerpc/watchdog: Tweak watchdog printks
powerpc/cell: Remove axonram driver
rtc-opal: Fix handling of firmware error codes, prevent busy loops
powerpc/mpc52xx_gpt: make use of raw_spinlock variants
macintosh/adb: Properly mark continued kernel messages
powerpc/pseries: Fix cpu hotplug crash with memoryless nodes
powerpc/numa: Ensure nodes initialized for hotplug
powerpc/numa: Use ibm,max-associativity-domains to discover possible nodes
powerpc/kernel: Block interrupts when updating TIDR
powerpc/powernv/idoa: Remove unnecessary pcidev from pci_dn
powerpc/mm/nohash: do not flush the entire mm when range is a single page
powerpc/pseries: Add Initialization of VF Bars
powerpc/pseries/pci: Associate PEs to VFs in configure SR-IOV
powerpc/eeh: Add EEH notify resume sysfs
powerpc/eeh: Add EEH operations to notify resume
...
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clear_thread_tidr() is called in interrupt context as a part of delayed
put of the task structure (i.e as a part of timer interrupt). To prevent
a deadlock, block interrupts when holding vas_thread_id_lock to set/
clear TIDR for a task.
Fixes: ec233ede4c86 ("powerpc: Add support for setting SPRN_TIDR")
Cc: [email protected] # v4.15+
Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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There are so many places that build struct siginfo by hand that at
least one of them is bound to get it wrong. A handful of cases in the
kernel arguably did just that when using the errno field of siginfo to
pass no errno values to userspace. The usage is limited to a single
si_code so at least does not mess up anything else.
Encapsulate this questionable pattern in a helper function so
that the userspace ABI is preserved.
Update all of the places that use this pattern to use the new helper
function.
Signed-off-by: "Eric W. Biederman" <[email protected]>
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signal_code is always TRAP_HWBKPT
Signed-off-by: "Eric W. Biederman" <[email protected]>
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Merge our fixes branch from the 4.15 cycle.
Unusually the fixes branch saw some significant features merged,
notably the RFI flush patches, so we want the code in next to be
tested against that, to avoid any surprises when the two are merged.
There's also some other work on the panic handling that was reverted
in fixes and we now want to do properly in next, which would conflict.
And we also fix a few other minor merge conflicts.
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Store and restore the AMR, IAMR and UAMOR register state of the task
before scheduling out and after scheduling in, respectively.
Signed-off-by: Ram Pai <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The POWER9 core supports a new feature: ASB_Notify which requires the
support of the Special Purpose Register: TIDR.
The ASB_Notify command, generated by the AFU, will attempt to
wake-up the host thread identified by the particular LPID:PID:TID.
This patch assign a unique TIDR (thread id) for the current thread which
will be used in the process element entry.
Signed-off-by: Christophe Lombard <[email protected]>
Reviewed-by: Philippe Bergheaud <[email protected]>
Acked-by: Frederic Barrat <[email protected]>
Reviewed-by: Vaibhav Jain <[email protected]>
Acked-by: Andrew Donnellan <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Two #defines IRQS_ENABLED and IRQS_DISABLED are added to be used when
updating paca->soft_enabled. Replace the hardcoded values used when
updating paca->soft_enabled with IRQ_(EN|DIS)ABLED #define. No logic
change.
Reviewed-by: Nicholas Piggin <[email protected]>
Signed-off-by: Madhavan Srinivasan <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Trap numbers can have extra bits at the bottom that need to
be filtered out. There are a few cases where we don't do that.
It's possible that we got lucky but better safe than sorry.
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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When we oops or otherwise call show_regs() we print the address of the
regs structure. Being able to see the address is fairly useful,
firstly to verify that the regs pointer is not completely bogus, and
secondly it allows you to dump the regs and surrounding memory with a
debugger if you have one.
In the normal case the regs will be located somewhere on the stack, so
printing their location discloses no further information than printing
the stack pointer does already.
So switch to %px and print the actual address, not the hashed value.
Signed-off-by: Michael Ellerman <[email protected]>
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If set_thread_tidr() is called twice for same task_struct then it will
allocate a new tidr value to it leaving the previous value still
dangling in the vas_thread_ida table.
To fix this the patch changes set_thread_tidr() to check if a tidr
value is already assigned to the task_struct and if yes then returns
zero.
Fixes: ec233ede4c86("powerpc: Add support for setting SPRN_TIDR")
Signed-off-by: Vaibhav Jain <[email protected]>
Reviewed-by: Andrew Donnellan <[email protected]>
[mpe: Modify to return 0 in the success case, not the TID value]
Signed-off-by: Michael Ellerman <[email protected]>
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There is an unsafe signed to unsigned conversion in set_thread_tidr()
that may cause an error value to be assigned to SPRN_TIDR register and
used as thread-id.
The issue happens as assign_thread_tidr() returns an int and
thread.tidr is an unsigned-long. So a negative error code returned
from assign_thread_tidr() will fail the error check and gets assigned
as tidr as a large positive value.
To fix this the patch assigns the return value of assign_thread_tidr()
to a temporary int and assigns it to thread.tidr iff its '> 0'.
The patch shouldn't impact the calling convention of set_thread_tidr()
i.e all -ve return-values are error codes and a return value of '0'
indicates success.
Fixes: ec233ede4c86("powerpc: Add support for setting SPRN_TIDR")
Signed-off-by: Vaibhav Jain <[email protected]>
Reviewed-by: Christophe Lombard [email protected]
Signed-off-by: Michael Ellerman <[email protected]>
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A CP_ABORT instruction is required in processes that have mapped a VAS
"paste address" with the intention of using COPY/PASTE instructions.
But since CP_ABORT is expensive, we want to restrict it to only
processes that use/intend to use COPY/PASTE.
Define an interface, set_thread_uses_vas(), that VAS can use to
indicate that the current process opened a send window. During context
switch, issue CP_ABORT only for processes that have the flag set.
Thanks for input from Nick Piggin, Michael Ellerman.
Signed-off-by: Sukadev Bhattiprolu <[email protected]>
[mpe: Fix to not use new_thread after _switch() returns]
Signed-off-by: Michael Ellerman <[email protected]>
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We need the SPRN_TIDR to be set for use with fast thread-wakeup (core-
to-core wakeup) and also with CAPI.
Each thread in a process needs to have a unique id within the process.
But for now, we assign globally unique thread ids to all threads in
the system.
Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Signed-off-by: Philippe Bergheaud <[email protected]>
Signed-off-by: Christophe Lombard <[email protected]>
[mpe: Simplify tidr clearing on fork() and ctx switch code]
Signed-off-by: Michael Ellerman <[email protected]>
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Lazy save and restore of FP/Altivec means that a userspace process can
be sent to userspace with FP or Altivec disabled and loaded only as
required (by way of an FP/Altivec unavailable exception). Transactional
Memory complicates this situation as a transaction could be started
without FP/Altivec being loaded up. This causes the hardware to
checkpoint incorrect registers. Handling FP/Altivec unavailable
exceptions while a thread is transactional requires a reclaim and
recheckpoint to ensure the CPU has correct state for both sets of
registers.
tm_reclaim() has optimisations to not always save the FP/Altivec
registers to the checkpointed save area. This was originally done
because the caller might have information that the checkpointed
registers aren't valid due to lazy save and restore. We've also been a
little vague as to how tm_reclaim() leaves the FP/Altivec state since it
doesn't necessarily always save it to the thread struct. This has lead
to an (incorrect) assumption that it leaves the checkpointed state on
the CPU.
tm_recheckpoint() has similar optimisations in reverse. It may not
always reload the checkpointed FP/Altivec registers from the thread
struct before the trecheckpoint. It is therefore quite unclear where it
expects to get the state from. This didn't help with the assumption
made about tm_reclaim().
These optimisations sit in what is by definition a slow path. If a
process has to go through a reclaim/recheckpoint then its transaction
will be doomed on returning to userspace. This mean that the process
will be unable to complete its transaction and be forced to its failure
handler. This is already an out if line case for userspace. Furthermore,
the cost of copying 64 times 128 bits from registers isn't very long[0]
(at all) on modern processors. As such it appears these optimisations
have only served to increase code complexity and are unlikely to have
had a measurable performance impact.
Our transactional memory handling has been riddled with bugs. A cause
of this has been difficulty in following the code flow, code complexity
has not been our friend here. It makes sense to remove these
optimisations in favour of a (hopefully) more stable implementation.
This patch does mean that some times the assembly will needlessly save
'junk' registers which will subsequently get overwritten with the
correct value by the C code which calls the assembly function. This
small inefficiency is far outweighed by the reduction in complexity for
general TM code, context switching paths, and transactional facility
unavailable exception handler.
0: I tried to measure it once for other work and found that it was
hiding in the noise of everything else I was working with. I find it
exceedingly likely this will be the case here.
Signed-off-by: Cyril Bur <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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exception
Lazy save and restore of FP/Altivec means that a userspace process can
be sent to userspace with FP or Altivec disabled and loaded only as
required (by way of an FP/Altivec unavailable exception). Transactional
Memory complicates this situation as a transaction could be started
without FP/Altivec being loaded up. This causes the hardware to
checkpoint incorrect registers. Handling FP/Altivec unavailable
exceptions while a thread is transactional requires a reclaim and
recheckpoint to ensure the CPU has correct state for both sets of
registers.
tm_reclaim() has optimisations to not always save the FP/Altivec
registers to the checkpointed save area. This was originally done
because the caller might have information that the checkpointed
registers aren't valid due to lazy save and restore. We've also been a
little vague as to how tm_reclaim() leaves the FP/Altivec state since it
doesn't necessarily always save it to the thread struct. This has lead
to an (incorrect) assumption that it leaves the checkpointed state on
the CPU.
tm_recheckpoint() has similar optimisations in reverse. It may not
always reload the checkpointed FP/Altivec registers from the thread
struct before the trecheckpoint. It is therefore quite unclear where it
expects to get the state from. This didn't help with the assumption
made about tm_reclaim().
This patch is a minimal fix for ease of backporting. A more correct fix
which removes the msr parameter to tm_reclaim() and tm_recheckpoint()
altogether has been upstreamed to apply on top of this patch.
Fixes: dc3106690b20 ("powerpc: tm: Always use fp_state and vr_state to
store live registers")
Signed-off-by: Cyril Bur <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Lazy save and restore of FP/Altivec means that a userspace process can
be sent to userspace with FP or Altivec disabled and loaded only as
required (by way of an FP/Altivec unavailable exception). Transactional
Memory complicates this situation as a transaction could be started
without FP/Altivec being loaded up. This causes the hardware to
checkpoint incorrect registers. Handling FP/Altivec unavailable
exceptions while a thread is transactional requires a reclaim and
recheckpoint to ensure the CPU has correct state for both sets of
registers.
Lazy save and restore of FP/Altivec cannot be done if a process is
transactional. If a facility was enabled it must remain enabled whenever
a thread is transactional.
Commit dc16b553c949 ("powerpc: Always restore FPU/VEC/VSX if hardware
transactional memory in use") ensures that the facilities are always
enabled if a thread is transactional. A bug in the introduced code may
cause it to inadvertently enable a facility that was (and should remain)
disabled. The problem with this extraneous enablement is that the
registers for the erroneously enabled facility have not been correctly
recheckpointed - the recheckpointing code assumed the facility would
remain disabled.
Further compounding the issue, the transactional {fp,altivec,vsx}
unavailable code has been incorrectly using the MSR to enable
facilities. The presence of the {FP,VEC,VSX} bit in the regs->msr simply
means if the registers are live on the CPU, not if the kernel should
load them before returning to userspace. This has worked due to the bug
mentioned above.
This causes transactional threads which return to their failure handler
to observe incorrect checkpointed registers. Perhaps an example will
help illustrate the problem:
A userspace process is running and uses both FP and Altivec registers.
This process then continues to run for some time without touching
either sets of registers. The kernel subsequently disables the
facilities as part of lazy save and restore. The userspace process then
performs a tbegin and the CPU checkpoints 'junk' FP and Altivec
registers. The process then performs a floating point instruction
triggering a fp unavailable exception in the kernel.
The kernel then loads the FP registers - and only the FP registers.
Since the thread is transactional it must perform a reclaim and
recheckpoint to ensure both the checkpointed registers and the
transactional registers are correct. It then (correctly) enables
MSR[FP] for the process. Later (on exception exist) the kernel also
(inadvertently) enables MSR[VEC]. The process is then returned to
userspace.
Since the act of loading the FP registers doomed the transaction we know
CPU will fail the transaction, restore its checkpointed registers, and
return the process to its failure handler. The problem is that we're
now running with Altivec enabled and the 'junk' checkpointed registers
are restored. The kernel had only recheckpointed FP.
This patch solves this by only activating FP/Altivec if userspace was
using them when it entered the kernel and not simply if the process is
transactional.
Fixes: dc16b553c949 ("powerpc: Always restore FPU/VEC/VSX if hardware
transactional memory in use")
Signed-off-by: Cyril Bur <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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CONFIG_PPC_STD_MMU_64 indicates support for the "standard" powerpc MMU
on 64-bit CPUs. The "standard" MMU refers to the hash page table MMU
found in "server" processors, from IBM mainly.
Currently CONFIG_PPC_STD_MMU_64 is == CONFIG_PPC_BOOK3S_64. While it's
annoying to have two symbols that always have the same value, it's not
quite annoying enough to bother removing one.
However with the arrival of Power9, we now have the situation where
CONFIG_PPC_STD_MMU_64 is enabled, but the kernel is running using the
Radix MMU - *not* the "standard" MMU. So it is now actively confusing
to use it, because it implies that code is disabled or inactive when
the Radix MMU is in use, however that is not necessarily true.
So s/CONFIG_PPC_STD_MMU_64/CONFIG_PPC_BOOK3S_64/, and do some minor
formatting updates of some of the affected lines.
This will be a pain for backports, but c'est la vie.
Signed-off-by: Michael Ellerman <[email protected]>
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Unfortunately userspace can construct a sigcontext which enables
suspend. Thus userspace can force Linux into a path where trechkpt is
executed.
This patch blocks this from happening on POWER9 by sanity checking
sigcontexts passed in.
ptrace doesn't have this problem as only MSR SE and BE can be changed
via ptrace.
This patch also adds a number of WARN_ON()s in case we ever enter
suspend when we shouldn't. This should not happen, but if it does the
symptoms are soft lockup warnings which are not obviously TM related,
so the WARN_ON()s should make it obvious what's happening.
Signed-off-by: Michael Neuling <[email protected]>
Signed-off-by: Cyril Bur <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Some Power9 revisions can run in a mode where TM operates without
suspended state. If we find ourself on a CPU that might be in this
mode, we query OPAL to check, and if so we reenable TM in CPU
features, and enable a new user feature to signal to userspace that we
are in this mode.
We do not enable the "normal" user feature, PPC_FEATURE2_HTM, but we
do enable PPC_FEATURE2_HTM_NOSC because that indicates to userspace
that the kernel will abort transactions on syscall entry, which is
true regardless of the suspend mode.
Signed-off-by: Michael Ellerman <[email protected]>
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Add a check for p->state == TASK_RUNNING so that any wake-ups on
task_struct p in the interim lead to 0 being returned by get_wchan().
Signed-off-by: Kautuk Consul <[email protected]>
[mpe: Confirmed other architectures do similar]
Signed-off-by: Michael Ellerman <[email protected]>
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This is purely cosmetic, but does look nicer IMHO:
Before:
task: c000000001453400 task.stack: c000000001c6c000
NIP: c000000000a0fbfc LR: c000000000a0fbf4 CTR: c000000000ba6220
REGS: c0000001fffef820 TRAP: 0300 Not tainted (4.13.0-rc6-gcc-6.3.1-00234-g423af27f7d81)
MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 88088242 XER: 00000000
CFAR: c0000000000b3488 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 0
After:
task: c000000001453400 task.stack: c000000001c6c000
NIP: c000000000a0fbfc LR: c000000000a0fbf4 CTR: c000000000ba6220
REGS: c0000001fffef820 TRAP: 0300 Not tainted (4.13.0-rc6-gcc-6.3.1-00234-g423af27f7d81-dirty)
MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 88088242 XER: 00000000
CFAR: c0000000000b34a4 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 0
Signed-off-by: Michael Ellerman <[email protected]>
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Somehow we missed this when the pr_cont() changes went in. Fix CR/XER
to go on the same line as MSR, as they have historically, eg:
MSR: 8000000000009032 <SF,EE,ME,IR,DR,RI> CR: 4804408a XER: 20000000
Signed-off-by: Michael Ellerman <[email protected]>
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On modern CPUs the CTRL register is read-only except bit 63 which is
the run latch control. This means it can be updated with a mtspr
rather than mfspr/mtspr.
To accomodate older CPUs (Cell at least), where there are other bits
in the register, we still do a read/modify/write on pre 2.06 CPUs.
Signed-off-by: Nicholas Piggin <[email protected]>
[mpe: Update change log to mention 2.06 workaround]
Signed-off-by: Michael Ellerman <[email protected]>
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There's a non-trivial dependency between some commits we want to put in
next and the KVM prefetch work around that went into fixes. So merge
fixes into next.
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__giveup_vsx/save_vsx are completely equivalent to testing MSR_FP
and MSR_VEC and calling the corresponding giveup/save function so
just remove the spurious VSX cases. Also add WARN_ONs checking that
we never have VSX enabled without the two other.
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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__giveup_fpu() already does it and we cannot have MSR_VSX set
without having MSR_FP also set.
This also adds a warning to check we indeed do
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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__giveup_vsx() already calls those two functions.
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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VSX uses a combination of the old vector registers, the old FP
registers and new "second halves" of the FP registers.
Thus when we need to see the VSX state in the thread struct
(flush_vsx_to_thread()) or when we'll use the VSX in the kernel
(enable_kernel_vsx()) we need to ensure they are all flushed into
the thread struct if either of them is individually enabled.
Unfortunately we only tested if the whole VSX was enabled, not if they
were individually enabled.
Fixes: 72cd7b44bc99 ("powerpc: Uncomment and make enable_kernel_vsx() routine available")
Cc: [email protected] # v4.3+
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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This reverts commit bc4f65e4cf9d6cc43e0e9ba0b8648cf9201cd55f.
As reported by Andreas, this commit is causing unrecoverable SLB misses in the
system call exit path:
Unrecoverable exception 4100 at c00000000000a1ec
Oops: Unrecoverable exception, sig: 6 [#1]
SMP NR_CPUS=2 PowerMac
...
CPU: 0 PID: 18626 Comm: rm Not tainted 4.13.0-rc3 #1
task: c00000018335e080 task.stack: c000000139e50000
NIP: c00000000000a1ec LR: c00000000000a118 CTR: 0000000000000000
REGS: c000000139e53bb0 TRAP: 4100 Not tainted (4.13.0-rc3)
MSR: 9000000000001030 <SF,HV,ME,IR,DR> CR: 24000044 XER: 20000000 SOFTE: 1
GPR00: 0000000000000000 c000000139e53e30 c000000000abb500 fffffffffffffffe
GPR04: c0000001eb866298 0000000000000000 0000000000000000 c00000018335e080
GPR08: 900000000000d032 0000000000000000 0000000000000002 fffffffffffff001
GPR12: c000000139e50000 c00000000ffff000 00003fffa8c0dca0 00003fffa8c0dc88
GPR16: 0000000010000000 0000000000000001 00003fffa8c0eaa0 0000000000000000
GPR20: 00003fffa8c27528 00003fffa8c27b00 0000000000000000 0000000000000000
GPR24: 00003fffa8c0d918 00003ffff1b3efa0 00003fffa8c26d68 0000000000000000
GPR28: 00003fffa8c249e8 00003fffa8c263d0 00003fffa8c27550 00003ffff1b3ef10
NIP [c00000000000a1ec] system_call_exit+0xc0/0x21c
LR [c00000000000a118] system_call+0x58/0x6c
Call Trace:
[c000000139e53e30] [c00000000000a118] system_call+0x58/0x6c (unreliable)
Instruction dump:
64a51000 7c6300d0 f8a101a0 4bffff9c 3c000000 60000006 780007c6 64000000
60000000 7c004039 4082001c e8ed0170 <88070b78> 88c70b79 7c003214 2c200000
This is caused by us trying to load THREAD_LOAD_FP with MSR_RI=0, and taking an
SLB miss on the thread struct.
Reported-by: Andreas Schwab <[email protected]>
Diagnosed-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Merge our fixes branch, a few of them are tripping people up while
working on top of next, and we also have a dependency between the CXL
fixes and new CXL code we want to merge into next.
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The ISA v3.0B copy-paste facility only requires cpabort when switching
to a process that has foreign real addresses mapped (direct access to
accelerators), to clear a potential copy buffer filled by a previous
thread. There is no accelerator driver implemented yet, so cpabort can
be removed. It can be be re-added when a driver is implemented.
POWER9 DD1 requires the copy buffer to always be cleared on context
switch, but if accelerators are not in use, then an unpaired copy from
a dummy region is sufficient to clear data out of the copy buffer.
This increases context switch performance by about 5% on POWER9.
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Commit 4387e9ff25 ("[POWERPC] Fix PMU + soft interrupt disable bug")
hard disabled interrupts over the low level context switch, because
the SLB management can't cope with a PMU interrupt accesing the stack
in that window.
Radix based kernel mapping does not use the SLB so it does not require
interrupts hard disabled here.
This is worth 1-2% in context switch performance on POWER9.
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The syscall exit code that branches to restore_math is quite heavy on
Book3S, consisting of 2 mtmsr instructions. Threads that don't use both
FP and vector can get caught here if the kernel ever uses FP or vector.
Lazy-FP/vec context switching also trips this case.
So check for lazy FP and vector before switching RI for restore_math.
Move most of this case out of line.
For threads that do want to restore math registers, the MSR switches are
still suboptimal. Future direction may be to use a soft-RI bit to avoid
MSR switches in kernel (similar to soft-EE), but for now at least the
no-restore
POWER9 context switch rate increases by about 5% due to sched_yield(2)
return performance. I haven't constructed a test to measure the syscall
cost.
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Currently tsk->thread.load_tm is not initialized in the task creation
and can contain garbage on a new task.
This is an undesired behaviour, since it affects the timing to enable
and disable the transactional memory laziness (disabling and enabling
the MSR TM bit, which affects TM reclaim and recheckpoint in the
scheduling process).
Fixes: 5d176f751ee3 ("powerpc: tm: Enable transactional memory (TM) lazily for userspace")
Cc: [email protected] # v4.9+
Signed-off-by: Breno Leitao <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Currently tsk->thread->load_vec and load_fp are not initialized during
task creation, which can lead to garbage values in these variables (non-zero
values).
These variables will be checked later in restore_math() to validate if the
FP and vector registers are being utilized. Since these values might be
non-zero, the restore_math() will continue to save the FP and vectors even if
they were never utilized by the userspace application. load_fp and load_vec
counters will then overflow (they wrap at 255) and the FP and Altivec will be
finally disabled, but before that condition is reached (counter overflow)
several context switches will have restored FP and vector registers without
need, causing a performance degradation.
Fixes: 70fe3d980f5f ("powerpc: Restore FPU/VEC/VSX if previously used")
Cc: [email protected] # v4.6+
Signed-off-by: Breno Leitao <[email protected]>
Signed-off-by: Gustavo Romero <[email protected]>
Acked-by: Anton Blanchard <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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In commit dc3106690b20 ("powerpc: tm: Always use fp_state and vr_state
to store live registers"), a section of code was removed that copied
the current state to checkpointed state. That code should not have been
removed.
When an FP (Floating Point) unavailable is taken inside a transaction,
we need to abort the transaction. This is because at the time of the
tbegin, the FP state is bogus so the state stored in the checkpointed
registers is incorrect. To fix this, we treclaim (to get the
checkpointed GPRs) and then copy the thread_struct FP live state into
the checkpointed state. We then trecheckpoint so that the FP state is
correctly restored into the CPU.
The copying of the FP registers from live to checkpointed is what was
missing.
This simplifies the logic slightly from the original patch.
tm_reclaim_thread() will now always write the checkpointed FP
state. Either the checkpointed FP state will be written as part of
the actual treclaim (in tm.S), or it'll be a copy of the live
state. Which one we use is based on MSR[FP] from userspace.
Similarly for VMX.
Fixes: dc3106690b20 ("powerpc: tm: Always use fp_state and vr_state to store live registers")
Cc: [email protected] # 4.9+
Signed-off-by: Michael Neuling <[email protected]>
Reviewed-by: [email protected]
Signed-off-by: Michael Ellerman <[email protected]>
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<linux/sched/task_stack.h>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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<linux/sched/task.h>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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<linux/sched/debug.h>
We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull more powerpc updates from Michael Ellerman:
"Highlights include:
- an update of the disassembly code used by xmon to the latest
versions in binutils. We've received permission from all the
authors of the relevant binutils changes to relicense their changes
to the relevant files from GPLv3 to GPLv2, for inclusion in Linux.
Thanks to Peter Bergner for doing the leg work to get permission
from everyone.
- addition of the "architected" Power9 CPU table entry, allowing us
to boot in Power9 architected mode under a hypervisor.
- updates to the Power9 PMU code.
- implementation of clear_bit_unlock_is_negative_byte() to optimise
unlock_page().
- Freescale updates from Scott: "Highlights include 8xx breakpoints
and perf, t1042rdb display support, and board updates."
Thanks to:
Al Viro, Andrew Donnellan, Aneesh Kumar K.V, Balbir Singh, Douglas
Miller, Frédéric Weisbecker, Gavin Shan, Madhavan Srinivasan,
Michael Roth, Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Peter
Bergner, Paul E. McKenney, Rashmica Gupta, Russell Currey, Sahil
Mehta, Stewart Smith"
* tag 'powerpc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (48 commits)
powerpc: Remove leftover cputime_to_nsecs call causing build error
powerpc/mm/hash: Always clear UPRT and Host Radix bits when setting up CPU
powerpc/optprobes: Fix TOC handling in optprobes trampoline
powerpc/pseries: Advertise Hot Plug Event support to firmware
cxl: fix nested locking hang during EEH hotplug
powerpc/xmon: Dump memory in CPU endian format
powerpc/pseries: Revert 'Auto-online hotplugged memory'
powerpc/powernv: Make PCI non-optional
powerpc/64: Implement clear_bit_unlock_is_negative_byte()
powerpc/powernv: Remove unused variable in pnv_pci_sriov_disable()
powerpc/kernel: Remove error message in pcibios_setup_phb_resources()
powerpc/mm: Fix typo in set_pte_at()
pci/hotplug/pnv-php: Disable MSI and PCI device properly
pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts
pci/hotplug/pnv-php: Remove WARN_ON() in pnv_php_put_slot()
powerpc: Add POWER9 architected mode to cputable
powerpc/perf: use is_kernel_addr macro in perf_get_misc_flags()
powerpc/perf: Avoid FAB_*_MATCH checks for power9
powerpc/perf: Add restrictions to PMC5 in power9 DD1
powerpc/perf: Use Instruction Counter value
...
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This patch implements HW breakpoint on the 8xx. The 8xx has
capability to manage HW breakpoints, which is slightly different
than BOOK3S:
1/ The breakpoint match doesn't trigger a DSI exception but a
dedicated data breakpoint exception.
2/ The breakpoint happens after the instruction has completed,
no need to single step or emulate the instruction,
3/ Matched address is not set in DAR but in BAR,
4/ DABR register doesn't exist, instead we have registers
LCTRL1, LCTRL2 and CMPx registers,
5/ The match on one comparator is not on a double word but
on a single word.
The patch does:
1/ Prepare the dedicated registers in call to __set_dabr(). In order
to emulate the double word handling of BOOK3S, comparator E is set to
DABR address value and comparator F to address + 4. Then breakpoint 1
is set to match comparator E or F,
2/ Skip the singlestepping stage when compiled for CONFIG_PPC_8xx,
3/ Implement the exception. In that exception, the matched address
is taken from SPRN_BAR and manage as if it was from SPRN_DAR.
4/ I/D TLB error exception routines perform a tlbie on bad TLBs. That
tlbie triggers the breakpoint exception when performed on the
breakpoint address. For this reason, the routine returns if the match
is from one of those two tlbie.
Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Scott Wood <[email protected]>
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