SLB faults should not be taken while the PACA save areas are live, all
memory accesses should be fetches from the kernel text, and access to
PACA and the current stack, before C code is called or any other
accesses are made.
All of these have pinned SLBs so will not take a SLB fault. Therefore
EXSLB is not be required.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210208063406.331655-1-npiggin@gmail.com
Access to per-cpu variables requires translation to be enabled on
pseries machine running in hash mmu mode, Since part of MCE handler
runs in realmode and part of MCE handling code is shared between ppc
architectures pseries and powernv, it becomes difficult to manage
these variables differently on different architectures, So have
these variables in paca instead of having them as per-cpu variables
to avoid complications.
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210128104143.70668-2-ganeshgr@linux.ibm.com
- Add support for (optionally) using queued spinlocks & rwlocks.
- Support for a new faster system call ABI using the scv instruction on Power9
or later.
- Drop support for the PROT_SAO mmap/mprotect flag as it will be unsupported on
Power10 and future processors, leaving us with no way to implement the
functionality it requests. This risks breaking userspace, though we believe
it is unused in practice.
- A bug fix for, and then the removal of, our custom stack expansion checking.
We now allow stack expansion up to the rlimit, like other architectures.
- Remove the remnants of our (previously disabled) topology update code, which
tried to react to NUMA layout changes on virtualised systems, but was prone
to crashes and other problems.
- Add PMU support for Power10 CPUs.
- A change to our signal trampoline so that we don't unbalance the link stack
(branch return predictor) in the signal delivery path.
- Lots of other cleanups, refactorings, smaller features and so on as usual.
Thanks to:
Abhishek Goel, Alastair D'Silva, Alexander A. Klimov, Alexey Kardashevskiy,
Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Anton
Blanchard, Arnd Bergmann, Athira Rajeev, Balamuruhan S, Bharata B Rao, Bill
Wendling, Bin Meng, Cédric Le Goater, Chris Packham, Christophe Leroy,
Christoph Hellwig, Daniel Axtens, Dan Williams, David Lamparter, Desnes A.
Nunes do Rosario, Erhard F., Finn Thain, Frederic Barrat, Ganesh Goudar,
Gautham R. Shenoy, Geoff Levand, Greg Kurz, Gustavo A. R. Silva, Hari Bathini,
Harish, Imre Kaloz, Joel Stanley, Joe Perches, John Crispin, Jordan Niethe,
Kajol Jain, Kamalesh Babulal, Kees Cook, Laurent Dufour, Leonardo Bras, Li
RongQing, Madhavan Srinivasan, Mahesh Salgaonkar, Mark Cave-Ayland, Michal
Suchanek, Milton Miller, Mimi Zohar, Murilo Opsfelder Araujo, Nathan
Chancellor, Nathan Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Oliver
O'Halloran, Palmer Dabbelt, Pedro Miraglia Franco de Carvalho, Philippe
Bergheaud, Pingfan Liu, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sam Bobroff, Sandipan Das, Santosh
Sivaraj, Satheesh Rajendran, Shirisha Ganta, Sourabh Jain, Srikar Dronamraju,
Stan Johnson, Stephen Rothwell, Thadeu Lima de Souza Cascardo, Thiago Jung
Bauermann, Tom Lane, Vaibhav Jain, Vladis Dronov, Wei Yongjun, Wen Xiong,
YueHaibing.
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Merge tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Add support for (optionally) using queued spinlocks & rwlocks.
- Support for a new faster system call ABI using the scv instruction on
Power9 or later.
- Drop support for the PROT_SAO mmap/mprotect flag as it will be
unsupported on Power10 and future processors, leaving us with no way
to implement the functionality it requests. This risks breaking
userspace, though we believe it is unused in practice.
- A bug fix for, and then the removal of, our custom stack expansion
checking. We now allow stack expansion up to the rlimit, like other
architectures.
- Remove the remnants of our (previously disabled) topology update
code, which tried to react to NUMA layout changes on virtualised
systems, but was prone to crashes and other problems.
- Add PMU support for Power10 CPUs.
- A change to our signal trampoline so that we don't unbalance the link
stack (branch return predictor) in the signal delivery path.
- Lots of other cleanups, refactorings, smaller features and so on as
usual.
Thanks to: Abhishek Goel, Alastair D'Silva, Alexander A. Klimov, Alexey
Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Balamuruhan
S, Bharata B Rao, Bill Wendling, Bin Meng, Cédric Le Goater, Chris
Packham, Christophe Leroy, Christoph Hellwig, Daniel Axtens, Dan
Williams, David Lamparter, Desnes A. Nunes do Rosario, Erhard F., Finn
Thain, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geoff Levand,
Greg Kurz, Gustavo A. R. Silva, Hari Bathini, Harish, Imre Kaloz, Joel
Stanley, Joe Perches, John Crispin, Jordan Niethe, Kajol Jain, Kamalesh
Babulal, Kees Cook, Laurent Dufour, Leonardo Bras, Li RongQing, Madhavan
Srinivasan, Mahesh Salgaonkar, Mark Cave-Ayland, Michal Suchanek, Milton
Miller, Mimi Zohar, Murilo Opsfelder Araujo, Nathan Chancellor, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Oliver O'Halloran,
Palmer Dabbelt, Pedro Miraglia Franco de Carvalho, Philippe Bergheaud,
Pingfan Liu, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sam Bobroff, Sandipan Das, Santosh
Sivaraj, Satheesh Rajendran, Shirisha Ganta, Sourabh Jain, Srikar
Dronamraju, Stan Johnson, Stephen Rothwell, Thadeu Lima de Souza
Cascardo, Thiago Jung Bauermann, Tom Lane, Vaibhav Jain, Vladis Dronov,
Wei Yongjun, Wen Xiong, YueHaibing.
* tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (337 commits)
selftests/powerpc: Fix pkey syscall redefinitions
powerpc: Fix circular dependency between percpu.h and mmu.h
powerpc/powernv/sriov: Fix use of uninitialised variable
selftests/powerpc: Skip vmx/vsx/tar/etc tests on older CPUs
powerpc/40x: Fix assembler warning about r0
powerpc/papr_scm: Add support for fetching nvdimm 'fuel-gauge' metric
powerpc/papr_scm: Fetch nvdimm performance stats from PHYP
cpuidle: pseries: Fixup exit latency for CEDE(0)
cpuidle: pseries: Add function to parse extended CEDE records
cpuidle: pseries: Set the latency-hint before entering CEDE
selftests/powerpc: Fix online CPU selection
powerpc/perf: Consolidate perf_callchain_user_[64|32]()
powerpc/pseries/hotplug-cpu: Remove double free in error path
powerpc/pseries/mobility: Add pr_debug() for device tree changes
powerpc/pseries/mobility: Set pr_fmt()
powerpc/cacheinfo: Warn if cache object chain becomes unordered
powerpc/cacheinfo: Improve diagnostics about malformed cache lists
powerpc/cacheinfo: Use name@unit instead of full DT path in debug messages
powerpc/cacheinfo: Set pr_fmt()
powerpc: fix function annotations to avoid section mismatch warnings with gcc-10
...
With the proposed change in percpu bootmem allocator to use page
mapping [1], the percpu first chunk memory area can come from vmalloc
ranges. This makes the HMI (Hypervisor Maintenance Interrupt) handler
crash the kernel whenever percpu variable is accessed in real mode.
This patch fixes this issue by moving the HMI IRQ stat inside paca for
safe access in realmode.
[1] https://lore.kernel.org/linuxppc-dev/20200608070904.387440-1-aneesh.kumar@linux.ibm.com/
Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159290806973.3642154.5244613424529764050.stgit@jupiter
In order to use <asm/percpu.h> in lockdep.h, we need to make sure
asm/percpu.h does not itself depend on lockdep.
The below seems to make that so and builds powerpc64-defconfig +
PROVE_LOCKING.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
https://lkml.kernel.org/r/20200623083721.336906073@infradead.org
Implement rtas_call_reentrant() for reentrant rtas-calls:
"ibm,int-on", "ibm,int-off",ibm,get-xive" and "ibm,set-xive".
On LoPAPR Version 1.1 (March 24, 2016), from 7.3.10.1 to 7.3.10.4,
items 2 and 3 say:
2 - For the PowerPC External Interrupt option: The * call must be
reentrant to the number of processors on the platform.
3 - For the PowerPC External Interrupt option: The * argument call
buffer for each simultaneous call must be physically unique.
So, these rtas-calls can be called in a lockless way, if using
a different buffer for each cpu doing such rtas call.
For this, it was suggested to add the buffer (struct rtas_args)
in the PACA struct, so each cpu can have it's own buffer.
The PACA struct received a pointer to rtas buffer, which is
allocated in the memory range available to rtas 32-bit.
Reentrant rtas calls are useful to avoid deadlocks in crashing,
where rtas-calls are needed, but some other thread crashed holding
the rtas.lock.
This is a backtrace of a deadlock from a kdump testing environment:
#0 arch_spin_lock
#1 lock_rtas ()
#2 rtas_call (token=8204, nargs=1, nret=1, outputs=0x0)
#3 ics_rtas_mask_real_irq (hw_irq=4100)
#4 machine_kexec_mask_interrupts
#5 default_machine_crash_shutdown
#6 machine_crash_shutdown
#7 __crash_kexec
#8 crash_kexec
#9 oops_end
Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
[mpe: Move under #ifdef PSERIES to avoid build breakage]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200518234245.200672-3-leobras.c@gmail.com
Notable changes:
- Removal of the NPU DMA code, used by the out-of-tree Nvidia driver, as well
as some other functions only used by drivers that haven't (yet?) made it
upstream.
- A fix for a bug in our handling of hardware watchpoints (eg. perf record -e
mem: ...) which could lead to register corruption and kernel crashes.
- Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for vmalloc
when using the Radix MMU.
- A large but incremental rewrite of our exception handling code to use gas
macros rather than multiple levels of nested CPP macros.
And the usual small fixes, cleanups and improvements.
Thanks to:
Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Cédric Le Goater,
Christian Lamparter, Christophe Leroy, Christophe Lombard, Christoph Hellwig,
Daniel Axtens, Denis Efremov, Enrico Weigelt, Frederic Barrat, Gautham R.
Shenoy, Geert Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg
Kurz, Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N. Rao,
Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi Bangoria,
Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher Boessenkool, Shaokun
Zhang, Shawn Anastasio, Stewart Smith, Suraj Jitindar Singh, Thiago Jung
Bauermann, YueHaibing.
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Merge tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Notable changes:
- Removal of the NPU DMA code, used by the out-of-tree Nvidia driver,
as well as some other functions only used by drivers that haven't
(yet?) made it upstream.
- A fix for a bug in our handling of hardware watchpoints (eg. perf
record -e mem: ...) which could lead to register corruption and
kernel crashes.
- Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for
vmalloc when using the Radix MMU.
- A large but incremental rewrite of our exception handling code to
use gas macros rather than multiple levels of nested CPP macros.
And the usual small fixes, cleanups and improvements.
Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab,
Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Arnd Bergmann,
Athira Rajeev, Cédric Le Goater, Christian Lamparter, Christophe
Leroy, Christophe Lombard, Christoph Hellwig, Daniel Axtens, Denis
Efremov, Enrico Weigelt, Frederic Barrat, Gautham R. Shenoy, Geert
Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg Kurz,
Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N.
Rao, Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi
Bangoria, Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher
Boessenkool, Shaokun Zhang, Shawn Anastasio, Stewart Smith, Suraj
Jitindar Singh, Thiago Jung Bauermann, YueHaibing"
* tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (163 commits)
powerpc/powernv/idle: Fix restore of SPRN_LDBAR for POWER9 stop state.
powerpc/eeh: Handle hugepages in ioremap space
ocxl: Update for AFU descriptor template version 1.1
powerpc/boot: pass CONFIG options in a simpler and more robust way
powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h
powerpc/irq: Don't WARN continuously in arch_local_irq_restore()
powerpc/module64: Use symbolic instructions names.
powerpc/module32: Use symbolic instructions names.
powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.h
powerpc/module64: Fix comment in R_PPC64_ENTRY handling
powerpc/boot: Add lzo support for uImage
powerpc/boot: Add lzma support for uImage
powerpc/boot: don't force gzipped uImage
powerpc/8xx: Add microcode patch to move SMC parameter RAM.
powerpc/8xx: Use IO accessors in microcode programming.
powerpc/8xx: replace #ifdefs by IS_ENABLED() in microcode.c
powerpc/8xx: refactor programming of microcode CPM params.
powerpc/8xx: refactor printing of microcode patch name.
powerpc/8xx: Refactor microcode write
powerpc/8xx: refactor writing of CPM microcode arrays
...
The bad stack test in interrupt handlers has a few problems. For
performance it is taken in the common case, which is a fetch bubble
and a waste of i-cache.
For code development and maintainence, it requires yet another stack
frame setup routine, and that constrains all exception handlers to
follow the same register save pattern which inhibits future
optimisation.
Remove the test/branch and replace it with a trap. Teach the program
check handler to use the emergency stack for this case.
This does not result in quite so nice a message, however the SRR0 and
SRR1 of the crashed interrupt can be seen in r11 and r12, as is the
original r1 (adjusted by INT_FRAME_SIZE). These are the most important
parts to debugging the issue.
The original r9-12 and cr0 is lost, which is the main downside.
kernel BUG at linux/arch/powerpc/kernel/exceptions-64s.S:847!
Oops: Exception in kernel mode, sig: 5 [#1]
BE SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted
NIP: c000000000009108 LR: c000000000cadbcc CTR: c0000000000090f0
REGS: c0000000fffcbd70 TRAP: 0700 Not tainted
MSR: 9000000000021032 <SF,HV,ME,IR,DR,RI> CR: 28222448 XER: 20040000
CFAR: c000000000009100 IRQMASK: 0
GPR00: 000000000000003d fffffffffffffd00 c0000000018cfb00 c0000000f02b3166
GPR04: fffffffffffffffd 0000000000000007 fffffffffffffffb 0000000000000030
GPR08: 0000000000000037 0000000028222448 0000000000000000 c000000000ca8de0
GPR12: 9000000002009032 c000000001ae0000 c000000000010a00 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: c0000000f00322c0 c000000000f85200 0000000000000004 ffffffffffffffff
GPR24: fffffffffffffffe 0000000000000000 0000000000000000 000000000000000a
GPR28: 0000000000000000 0000000000000000 c0000000f02b391c c0000000f02b3167
NIP [c000000000009108] decrementer_common+0x18/0x160
LR [c000000000cadbcc] .vsnprintf+0x3ec/0x4f0
Call Trace:
Instruction dump:
996d098a 994d098b 38610070 480246ed 48005518 60000000 38200000 718a4000
7c2a0b78 3821fd00 41c20008 e82d0970 <0981fd00> f92101a0 f9610170 f9810178
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Highlights:
- Support for Kernel Userspace Access/Execution Prevention (like
SMAP/SMEP/PAN/PXN) on some 64-bit and 32-bit CPUs. This prevents the kernel
from accidentally accessing userspace outside copy_to/from_user(), or
ever executing userspace.
- KASAN support on 32-bit.
- Rework of where we map the kernel, vmalloc, etc. on 64-bit hash to use the
same address ranges we use with the Radix MMU.
- A rewrite into C of large parts of our idle handling code for 64-bit Book3S
(ie. power8 & power9).
- A fast path entry for syscalls on 32-bit CPUs, for a 12-17% speedup in the
null_syscall benchmark.
- On 64-bit bare metal we have support for recovering from errors with the time
base (our clocksource), however if that fails currently we hang in __delay()
and never crash. We now have support for detecting that case and short
circuiting __delay() so we at least panic() and reboot.
- Add support for optionally enabling the DAWR on Power9, which had to be
disabled by default due to a hardware erratum. This has the effect of
enabling hardware breakpoints for GDB, the downside is a badly behaved
program could crash the machine by pointing the DAWR at cache inhibited
memory. This is opt-in obviously.
- xmon, our crash handler, gets support for a read only mode where operations
that could change memory or otherwise disturb the system are disabled.
Plus many clean-ups, reworks and minor fixes etc.
Thanks to:
Christophe Leroy, Akshay Adiga, Alastair D'Silva, Alexey Kardashevskiy, Andrew
Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Ben Hutchings,
Bo YU, Breno Leitao, Cédric Le Goater, Christopher M. Riedl, Christoph
Hellwig, Colin Ian King, David Gibson, Ganesh Goudar, Gautham R. Shenoy,
George Spelvin, Greg Kroah-Hartman, Greg Kurz, Horia Geantă, Jagadeesh
Pagadala, Joel Stanley, Joe Perches, Julia Lawall, Laurentiu Tudor, Laurent
Vivier, Lukas Bulwahn, Madhavan Srinivasan, Mahesh Salgaonkar, Mathieu
Malaterre, Michael Neuling, Mukesh Ojha, Nathan Fontenot, Nathan Lynch,
Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Peng Hao, Qian Cai, Ravi
Bangoria, Rick Lindsley, Russell Currey, Sachin Sant, Stewart Smith, Sukadev
Bhattiprolu, Thomas Huth, Tobin C. Harding, Tyrel Datwyler, Valentin
Schneider, Wei Yongjun, Wen Yang, YueHaibing.
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Merge tag 'powerpc-5.2-1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Slightly delayed due to the issue with printk() calling
probe_kernel_read() interacting with our new user access prevention
stuff, but all fixed now.
The only out-of-area changes are the addition of a cpuhp_state, small
additions to Documentation and MAINTAINERS updates.
Highlights:
- Support for Kernel Userspace Access/Execution Prevention (like
SMAP/SMEP/PAN/PXN) on some 64-bit and 32-bit CPUs. This prevents
the kernel from accidentally accessing userspace outside
copy_to/from_user(), or ever executing userspace.
- KASAN support on 32-bit.
- Rework of where we map the kernel, vmalloc, etc. on 64-bit hash to
use the same address ranges we use with the Radix MMU.
- A rewrite into C of large parts of our idle handling code for
64-bit Book3S (ie. power8 & power9).
- A fast path entry for syscalls on 32-bit CPUs, for a 12-17% speedup
in the null_syscall benchmark.
- On 64-bit bare metal we have support for recovering from errors
with the time base (our clocksource), however if that fails
currently we hang in __delay() and never crash. We now have support
for detecting that case and short circuiting __delay() so we at
least panic() and reboot.
- Add support for optionally enabling the DAWR on Power9, which had
to be disabled by default due to a hardware erratum. This has the
effect of enabling hardware breakpoints for GDB, the downside is a
badly behaved program could crash the machine by pointing the DAWR
at cache inhibited memory. This is opt-in obviously.
- xmon, our crash handler, gets support for a read only mode where
operations that could change memory or otherwise disturb the system
are disabled.
Plus many clean-ups, reworks and minor fixes etc.
Thanks to: Christophe Leroy, Akshay Adiga, Alastair D'Silva, Alexey
Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar,
Anton Blanchard, Ben Hutchings, Bo YU, Breno Leitao, Cédric Le Goater,
Christopher M. Riedl, Christoph Hellwig, Colin Ian King, David Gibson,
Ganesh Goudar, Gautham R. Shenoy, George Spelvin, Greg Kroah-Hartman,
Greg Kurz, Horia Geantă, Jagadeesh Pagadala, Joel Stanley, Joe
Perches, Julia Lawall, Laurentiu Tudor, Laurent Vivier, Lukas Bulwahn,
Madhavan Srinivasan, Mahesh Salgaonkar, Mathieu Malaterre, Michael
Neuling, Mukesh Ojha, Nathan Fontenot, Nathan Lynch, Nicholas Piggin,
Nick Desaulniers, Oliver O'Halloran, Peng Hao, Qian Cai, Ravi
Bangoria, Rick Lindsley, Russell Currey, Sachin Sant, Stewart Smith,
Sukadev Bhattiprolu, Thomas Huth, Tobin C. Harding, Tyrel Datwyler,
Valentin Schneider, Wei Yongjun, Wen Yang, YueHaibing"
* tag 'powerpc-5.2-1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (205 commits)
powerpc/64s: Use early_mmu_has_feature() in set_kuap()
powerpc/book3s/64: check for NULL pointer in pgd_alloc()
powerpc/mm: Fix hugetlb page initialization
ocxl: Fix return value check in afu_ioctl()
powerpc/mm: fix section mismatch for setup_kup()
powerpc/mm: fix redundant inclusion of pgtable-frag.o in Makefile
powerpc/mm: Fix makefile for KASAN
powerpc/kasan: add missing/lost Makefile
selftests/powerpc: Add a signal fuzzer selftest
powerpc/booke64: set RI in default MSR
ocxl: Provide global MMIO accessors for external drivers
ocxl: move event_fd handling to frontend
ocxl: afu_irq only deals with IRQ IDs, not offsets
ocxl: Allow external drivers to use OpenCAPI contexts
ocxl: Create a clear delineation between ocxl backend & frontend
ocxl: Don't pass pci_dev around
ocxl: Split pci.c
ocxl: Remove some unused exported symbols
ocxl: Remove superfluous 'extern' from headers
ocxl: read_pasid never returns an error, so make it void
...
Reimplement Book3S idle code in C, moving POWER7/8/9 implementation
speific HV idle code to the powernv platform code.
Book3S assembly stubs are kept in common code and used only to save
the stack frame and non-volatile GPRs before executing architected
idle instructions, and restoring the stack and reloading GPRs then
returning to C after waking from idle.
The complex logic dealing with threads and subcores, locking, SPRs,
HMIs, timebase resync, etc., is all done in C which makes it more
maintainable.
This is not a strict translation to C code, there are some
significant differences:
- Idle wakeup no longer uses the ->cpu_restore call to reinit SPRs,
but saves and restores them itself.
- The optimisation where EC=ESL=0 idle modes did not have to save GPRs
or change MSR is restored, because it's now simple to do. ESL=1
sleeps that do not lose GPRs can use this optimization too.
- KVM secondary entry and cede is now more of a call/return style
rather than branchy. nap_state_lost is not required because KVM
always returns via NVGPR restoring path.
- KVM secondary wakeup from offline sequence is moved entirely into
the offline wakeup, which avoids a hwsync in the normal idle wakeup
path.
Performance measured with context switch ping-pong on different
threads or cores, is possibly improved a small amount, 1-3% depending
on stop state and core vs thread test for shallow states. Deep states
it's in the noise compared with other latencies.
KVM improvements:
- Idle sleepers now always return to caller rather than branch out
to KVM first.
- This allows optimisations like very fast return to caller when no
state has been lost.
- KVM no longer requires nap_state_lost because it controls NVGPR
save/restore itself on the way in and out.
- The heavy idle wakeup KVM request check can be moved out of the
normal host idle code and into the not-performance-critical offline
code.
- KVM nap code now returns from where it is called, which makes the
flow a bit easier to follow.
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Squash the KVM changes in]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In a bid to kill off explicit mmiowb() usage in driver code, hook up
the asm-generic mmiowb() tracking code but provide a definition of
arch_mmiowb_state() so that the tracking data can remain in the paca
as it does at present
This replaces the existing (flawed) implementation.
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This adds CONFIG_DEBUG_VM checks to ensure:
- The kernel stack is in the SLB after it's flushed and bolted.
- We don't insert an SLB for an address that is aleady in the SLB.
- The kernel SLB miss handler does not take an SLB miss.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add 32-entry bitmaps to track the allocation status of the first 32
SLB entries, and whether they are user or kernel entries. These are
used to allocate free SLB entries first, before resorting to the round
robin allocator.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On PPC64, as register r13 points to the paca_struct at all time,
this patch adds a copy of the canary there, which is copied at
task_switch.
That new canary is then used by using the following GCC options:
-mstack-protector-guard=tls
-mstack-protector-guard-reg=r13
-mstack-protector-guard-offset=offsetof(struct paca_struct, canary))
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This reverts commits:
5e46e29e6a ("powerpc/64s/hash: convert SLB miss handlers to C")
8fed04d0f6 ("powerpc/64s/hash: remove user SLB data from the paca")
655deecf67 ("powerpc/64s/hash: SLB allocation status bitmaps")
2e1626744e ("powerpc/64s/hash: provide arch_setup_exec hooks for hash slice setup")
89ca4e126a ("powerpc/64s/hash: Add a SLB preload cache")
This series had a few bugs, and the fixes are not all trivial. So
revert most of it for now.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add 32-entry bitmaps to track the allocation status of the first 32
SLB entries, and whether they are user or kernel entries. These are
used to allocate free SLB entries first, before resorting to the round
robin allocator.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
User SLB mappig data is copied into the PACA from the mm->context so
it can be accessed by the SLB miss handlers.
After the C conversion, SLB miss handlers now run with relocation on,
and user SLB misses are able to take recursive kernel SLB misses, so
the user SLB mapping data can be removed from the paca and accessed
directly.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
rtas_log_buf is a buffer to hold RTAS event data that are communicated
to kernel by hypervisor. This buffer is then used to pass RTAS event
data to user through proc fs. This buffer is allocated from
vmalloc (non-linear mapping) area.
On Machine check interrupt, register r3 points to RTAS extended event
log passed by hypervisor that contains the MCE event. The pseries
machine check handler then logs this error into rtas_log_buf. The
rtas_log_buf is a vmalloc-ed (non-linear) buffer we end up taking up a
page fault (vector 0x300) while accessing it. Since machine check
interrupt handler runs in NMI context we can not afford to take any
page fault. Page faults are not honored in NMI context and causes
kernel panic. Apart from that, as Nick pointed out,
pSeries_log_error() also takes a spin_lock while logging error which
is not safe in NMI context. It may endup in deadlock if we get another
MCE before releasing the lock. Fix this by deferring the logging of
rtas error to irq work queue.
Current implementation uses two different buffers to hold rtas error
log depending on whether extended log is provided or not. This makes
bit difficult to identify which buffer has valid data that needs to
logged later in irq work. Simplify this using single buffer, one per
paca, and copy rtas log to it irrespective of whether extended log is
provided or not. Allocate this buffer below RMA region so that it can
be accessed in real mode mce handler.
Fixes: b96672dd84 ("powerpc: Machine check interrupt is a non-maskable interrupt")
Cc: stable@vger.kernel.org # v4.14+
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
POWER9 DD1 was never a product. It is no longer supported by upstream
firmware, and it is not effectively supported in Linux due to lack of
testing.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
[mpe: Remove arch_make_huge_pte() entirely]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
A CPU that gets stuck with interrupts hard disable can be difficult to
debug, as on some platforms we have no way to interrupt the CPU to
find out what it's doing.
A stop-gap is to have the CPU save it's stack pointer (r1) in its paca
when it hard disables interrupts. That way if we can't interrupt it,
we can at least trace the stack based on where it last disabled
interrupts.
In some cases that will be total junk, but the stack trace code should
handle that. In the simple case of a CPU that disable interrupts and
then gets stuck in a loop, the stack trace should be informative.
We could clear the saved stack pointer when we enable interrupts, but
that loses information which could be useful if we have nothing else
to go on.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
We ended up with an ugly conflict between fixes and next in ftrace.h
involving multiple nested ifdefs, and the automatic resolution is
wrong. So merge fixes into next so we can fix it up.
In commit 4e26bc4a4e ("powerpc/64: Rename soft_enabled to
irq_soft_mask") we renamed paca->soft_enabled. But then in commit
8e0b634b13 ("powerpc/64s: Do not allocate lppaca if we are not
virtualized") we added it back. Oops. This happened because the two
patches were in flight at the same time and rebased vs each other
multiple times, and we missed it in review.
Fixes: 8e0b634b13 ("powerpc/64s: Do not allocate lppaca if we are not virtualized")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We have some C code that we call into from real mode where we cannot
take any exceptions. Though the C functions themselves are mostly safe,
if these functions are traced, there is a possibility that we may take
an exception. For instance, in certain conditions, the ftrace code uses
WARN(), which uses a 'trap' to do its job.
For such scenarios, introduce a new field in paca 'ftrace_enabled',
which is checked on ftrace entry before continuing. This field can then
be set to zero to disable/pause ftrace, and set to a non-zero value to
resume ftrace.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Bring in yet another series that touches KVM code, and might need to
be merged into the kvm-ppc branch to resolve conflicts.
This required some changes in pnv_power9_force_smt4_catch/release()
due to the paca array becomming an array of pointers.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Rename the dummy allocate_pacas() to fix 32-bit build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Change the paca array into an array of pointers to pacas. Allocate
pacas individually.
This allows flexibility in where the PACAs are allocated. Future work
will allocate them node-local. Platforms that don't have address limits
on PACAs would be able to defer PACA allocations until later in boot
rather than allocate all possible ones up-front then freeing unused.
This is slightly more overhead (one additional indirection) for cross
CPU paca references, but those aren't too common.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The "lppaca" is a structure registered with the hypervisor. This is
unnecessary when running on non-virtualised platforms. One field from
the lppaca (pmcregs_in_use) is also used by the host, so move the host
part out into the paca (lppaca field is still updated in
guest mode).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix non-pseries build with some #ifdefs]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
POWER9 processors up to and including "Nimbus" v2.2 have hardware
bugs relating to transactional memory and thread reconfiguration.
One of these bugs has a workaround which is to get the core into
SMT4 state temporarily. This workaround is only needed when
running bare-metal.
This patch provides a function which gets the core into SMT4 mode
by preventing threads from going to a stop state, and waking up
those which are already in a stop state. Once at least 3 threads
are not in a stop state, the core will be in SMT4 and we can
continue.
To do this, we add a "dont_stop" flag to the paca to tell the
thread not to go into a stop state. If this flag is set,
power9_idle_stop() just returns immediately with a return value
of 0. The pnv_power9_force_smt4_catch() function does the following:
1. Set the dont_stop flag for each thread in the core, except
ourselves (in fact we use an atomic_inc() in case more than
one thread is calling this function concurrently).
2. See how many threads are awake, indicated by their
requested_psscr field in the paca being 0. If this is at
least 3, skip to step 5.
3. Send a doorbell interrupt to each thread that was seen as
being in a stop state in step 2.
4. Until at least 3 threads are awake, scan the threads to which
we sent a doorbell interrupt and check if they are awake now.
This relies on the following properties:
- Once dont_stop is non-zero, requested_psccr can't go from zero to
non-zero, except transiently (and without the thread doing stop).
- requested_psscr being zero guarantees that the thread isn't in
a state-losing stop state where thread reconfiguration could occur.
- Doing stop with a PSSCR value of 0 won't be a state-losing stop
and thus won't allow thread reconfiguration.
- Once threads_per_core/2 + 1 (i.e. 3) threads are awake, the core
must be in SMT4 mode, since SMT modes are powers of 2.
This does add a sync to power9_idle_stop(), which is necessary to
provide the correct ordering between setting requested_psscr and
checking dont_stop. The overhead of the sync should be unnoticeable
compared to the latency of going into and out of a stop state.
Because some objected to incurring this extra latency on systems where
the XER[SO] bug is not relevant, I have put the test in
power9_idle_stop inside a feature section. This means that
pnv_power9_force_smt4_catch() WILL NOT WORK correctly on systems
without the CPU_FTR_P9_TM_XER_SO_BUG feature bit set, and will
probably hang the system.
In order to cater for uses where the caller has an operation that
has to be done while the core is in SMT4, the core continues to be
kept in SMT4 after pnv_power9_force_smt4_catch() function returns,
until the pnv_power9_force_smt4_release() function is called.
It undoes the effect of step 1 above and allows the other threads
to go into a stop state.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
While the implementation of the "slices" address space allows
a significant amount of high slices, it limits the number of
low slices to 16 due to the use of a single u64 low_slices_psize
element in struct mm_context_t
On the 8xx, the minimum slice size is the size of the area
covered by a single PMD entry, ie 4M in 4K pages mode and 64M in
16K pages mode. This means we could have at least 64 slices.
In order to override this limitation, this patch switches the
handling of low_slices_psize to char array as done already for
high_slices_psize.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The fallback RFI flush is used when firmware does not provide a way
to flush the cache. It's a "displacement flush" that evicts useful
data by displacing it with an uninteresting buffer.
The flush has to take care to work with implementation specific cache
replacment policies, so the recipe has been in flux. The initial
slow but conservative approach is to touch all lines of a congruence
class, with dependencies between each load. It has since been
determined that a linear pattern of loads without dependencies is
sufficient, and is significantly faster.
Measuring the speed of a null syscall with RFI fallback flush enabled
gives the relative improvement:
P8 - 1.83x
P9 - 1.75x
The flush also becomes simpler and more adaptable to different cache
geometries.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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.
Rename the paca->soft_enabled to paca->irq_soft_mask as it is no
longer used as a flag for interrupt state, but a mask.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On some CPUs we can prevent the Meltdown vulnerability by flushing the
L1-D cache on exit from kernel to user mode, and from hypervisor to
guest.
This is known to be the case on at least Power7, Power8 and Power9. At
this time we do not know the status of the vulnerability on other CPUs
such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale
CPUs. As more information comes to light we can enable this, or other
mechanisms on those CPUs.
The vulnerability occurs when the load of an architecturally
inaccessible memory region (eg. userspace load of kernel memory) is
speculatively executed to the point where its result can influence the
address of a subsequent speculatively executed load.
In order for that to happen, the first load must hit in the L1,
because before the load is sent to the L2 the permission check is
performed. Therefore if no kernel addresses hit in the L1 the
vulnerability can not occur. We can ensure that is the case by
flushing the L1 whenever we return to userspace. Similarly for
hypervisor vs guest.
In order to flush the L1-D cache on exit, we add a section of nops at
each (h)rfi location that returns to a lower privileged context, and
patch that with some sequence. Newer firmwares are able to advertise
to us that there is a special nop instruction that flushes the L1-D.
If we do not see that advertised, we fall back to doing a displacement
flush in software.
For guest kernels we support migration between some CPU versions, and
different CPUs may use different flush instructions. So that we are
prepared to migrate to a machine with a different flush instruction
activated, we may have to patch more than one flush instruction at
boot if the hypervisor tells us to.
In the end this patch is mostly the work of Nicholas Piggin and
Michael Ellerman. However a cast of thousands contributed to analysis
of the issue, earlier versions of the patch, back ports testing etc.
Many thanks to all of them.
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Radix keeps no meaningful state in addr_limit, so remove it from radix
code and rename to slb_addr_limit to make it clear it applies to hash
only.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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 <mpe@ellerman.id.au>
POWER9 DD2.1 and earlier has an issue where some cache inhibited
vector load will return bad data. The workaround is two part, one
firmware/microcode part triggers HMI interrupts when hitting such
loads, the other part is this patch which then emulates the
instructions in Linux.
The affected instructions are limited to lxvd2x, lxvw4x, lxvb16x and
lxvh8x.
When an instruction triggers the HMI, all threads in the core will be
sent to the HMI handler, not just the one running the vector load.
In general, these spurious HMIs are detected by the emulation code and
we just return back to the running process. Unfortunately, if a
spurious interrupt occurs on a vector load that's to normal memory we
have no way to detect that it's spurious (unless we walk the page
tables, which is very expensive). In this case we emulate the load but
we need do so using a vector load itself to ensure 128bit atomicity is
preserved.
Some additional debugfs emulated instruction counters are added also.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Switch CONFIG_PPC_BOOK3S_64 to CONFIG_VSX to unbreak the build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The stop4 idle state on POWER9 is a deep idle state which loses
hypervisor resources, but whose latency is low enough that it can be
exposed via cpuidle.
Until now, the deep idle states which lose hypervisor resources (eg:
winkle) were only exposed via CPU-Hotplug. Hence currently on wakeup
from such states, barring a few SPRs which need to be restored to
their older value, rest of the SPRS are reinitialized to their values
corresponding to that at boot time.
When stop4 is used in the context of cpuidle, we want these additional
SPRs to be restored to their older value, to ensure that the context
on the CPU coming back from idle is same as it was before going idle.
In this patch, we define a SPR save area in PACA (since we have used
up the volatile register space in the stack) and on POWER9, we restore
SPRN_PID, SPRN_LDBAR, SPRN_FSCR, SPRN_HFSCR, SPRN_MMCRA, SPRN_MMCR1,
SPRN_MMCR2 to the values they had before entering stop.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Rather than open-coding it 4 times.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move __ASSEMBLY__ guards into head-64.h where they're really needed]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On Power9 DD1 due to a hardware bug the Power-Saving Level Status
field (PLS) of the PSSCR for a thread waking up from a deep state can
under-report if some other thread in the core is in a shallow stop
state. The scenario in which this can manifest is as follows:
1) All the threads of the core are in deep stop.
2) One of the threads is woken up. The PLS for this thread will
correctly reflect that it is waking up from deep stop.
3) The thread that has woken up now executes a shallow stop.
4) When some other thread in the core is woken, its PLS will reflect
the shallow stop state.
Thus, the subsequent thread for which the PLS is under-reporting the
wakeup state will not restore the hypervisor resources.
Hence, on DD1 systems, use the Requested Level (RL) field as a
workaround to restore the contents of the hypervisor resources on the
wakeup from the stop state.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The system reset interrupt is used for crash/debug situations, so it is
desirable to have as little impact on the normal state of the system as
possible.
Currently it uses the current kernel stack to process the exception.
This stores into the stack which may be involved with the crash. The
stack pointer may be corrupted, or it may have overflowed.
Avoid or minimise these problems by creating a dedicated NMI stack for
the system reset interrupt to use.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In preparation for using a dedicated stack for system reset interrupts,
prevent a nested system reset from recovering, in order to simplify
code that is called in crash/debug path. This allows a system reset
interrupt to just use the base stack pointer.
Keep an in_nmi nesting counter similarly to the in_mce counter. Consider
the interrrupt non-recoverable if it is taken inside another system
reset.
Interrupt nesting could be allowed similarly to MCE, but system reset
is a special case that's not for normal operation, so simplicity wins
until there is requirement for nested system reset interrupts.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The system reset interrupt can occur when MSR_EE=0, and it currently
uses the PACA_EXGEN save area.
Some PACA_EXGEN interrupts have a window where MSR_RI=1 and MSR_EE=0
when the save area is still in use. A system reset interrupt in this
window can lead to undetected corruption when the save area gets
overwritten.
This patch introduces PACA_EXNMI save area for system reset exceptions,
which closes this corruption window. It's also helpful to retain the
EXGEN state for debugging situations, even if not considering the
recoverability aspect.
This patch also moves the PACA_EXMC area down to a less frequently used
part of the paca with the new save area.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
POWER9 DD1.0 hardware has a bug where the SPRs of a thread waking up
from stop 0,1,2 with ESL=1 can endup being misplaced in the core. Thus
the HSPRG0 of a thread waking up from can contain the paca pointer of
its sibling.
This patch implements a context recovery framework within threads of a
core, by provisioning space in paca_struct for saving every sibling
threads's paca pointers. Basically, we should be able to arrive at the
right paca pointer from any of the thread's existing paca pointer.
At bootup, during powernv idle-init, we save the paca address of every
CPU in each one its siblings paca_struct in the slot corresponding to
this CPU's index in the core.
On wakeup from a stop, the thread will determine its index in the core
from the TIR register and recover its PACA pointer by indexing into
the correct slot in the provisioned space in the current PACA.
Furthermore, ensure that the NVGPRs are restored from the stack on the
way out by setting the NAPSTATELOST in paca.
[Changelog written with inputs from svaidy@linux.vnet.ibm.com]
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Call it a bug]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We optmize the slice page size array copy to paca by copying only the
range based on addr_limit. This will require us to not look at page size
array beyond addr_limit in PACA on slb fault. To enable that copy task
size to paca which will be used during slb fault.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Rename from task_size to addr_limit, consolidate #ifdefs]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We also update the function arg to struct mm_struct. Move this so that function
finds the definition of struct mm_struct. No functional change in this patch.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
That in order to gather all cputime accumulation to the same place.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1483636310-6557-7-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
