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2020-04-20powerpc: Use mm_context vas_windows counter to issue CP_ABORTHaren Myneni1-9/+13
set_thread_uses_vas() sets used_vas flag for a process that opened VAS window and issue CP_ABORT during context switch for only that process. In multi-thread application, windows can be shared. For example Thread A can open a window and Thread B can run COPY/PASTE instructions to send NX request which may cause corruption or snooping or a covert channel Also once this flag is set, continue to run CP_ABORT even the VAS window is closed. So define vas-windows counter in process mm_context, increment this counter for each window open and decrement it for window close. If vas-windows is set, issue CP_ABORT during context switch. It means clear the foreign real address mapping only if the process / thread uses COPY/PASTE. Then disable it for that process if windows are not open. Moved set_thread_uses_vas() code to vas_tx_win_open() as this functionality is needed only for userspace open windows. We are adding VAS userspace support along with this fix. So no need to include this fix in stable releases. Fixes: 9d2a4d71332c ("powerpc: Define set_thread_uses_vas()") Signed-off-by: Haren Myneni <haren@linux.ibm.com> Reported-by: Nicholas Piggin <npiggin@gmail.com> Suggested-by: Milton Miller <miltonm@us.ibm.com> Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587017291.2275.1077.camel@hbabu-laptop
2020-04-20powerpc/vas: Free send window in VAS instance after credits returnedHaren Myneni1-2/+2
NX may be processing requests while trying to close window. Wait until all credits are returned and then free send window from VAS instance. Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587017256.2275.1076.camel@hbabu-laptop
2020-04-20powerpc/vas: Display process stuck messageHaren Myneni1-1/+29
Process can not close send window until all requests are processed. Means wait until window state is not busy and send credits are returned. Display debug messages in case taking longer to close the window. Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587017219.2275.1073.camel@hbabu-laptop
2020-04-20powerpc/vas: Do not use default credits for receive windowHaren Myneni2-4/+2
System checkstops if RxFIFO overruns with more requests than the maximum possible number of CRBs allowed in FIFO at any time. So max credits value (rxattr.wcreds_max) is set and is passed to vas_rx_win_open() by the the driver. Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587017136.2275.1070.camel@hbabu-laptop
2020-04-20powerpc/vas: Print CRB and FIFO valuesHaren Myneni1-0/+41
Dump FIFO entries if could not find send window and print CRB for debugging. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587017099.2275.1067.camel@hbabu-laptop
2020-04-20powerpc/vas: Return credits after handling faultHaren Myneni3-0/+46
NX uses credit mechanism to control the number of requests issued on a specific window at any point of time. Only send windows and fault window are used credits. When the request is issued on a given window, a credit is taken. This credit will be returned after that request is processed. If credits are not available, returns RMA_Busy for send window and RMA_Reject for fault window. NX expects OS to return credit for send window after processing fault CRB. Also credit has to be returned for fault window after handling the fault. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587017059.2275.1064.camel@hbabu-laptop
2020-04-20powerpc/vas: Update CSB and notify process for fault CRBsHaren Myneni1-1/+125
Applications polls on CSB for the status update after requests are issued. NX process these requests and update the CSB with the status. If it encounters translation error, pastes CRB in fault FIFO and raises an interrupt. The kernel handles fault by reading CRB from fault FIFO and process the fault CRB. For each fault CRB, update fault address in CRB (fault_storage_addr) and translation error status in CSB so that user space can touch the fault address and resend the request. If the user space passed invalid CSB address send signal to process with SIGSEGV. In the case of multi-thread applications, child thread may not be available. So if the task is not running, send signal to tgid. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587017022.2275.1063.camel@hbabu-laptop
2020-04-20powerpc/vas: Setup thread IRQ handler per VAS instanceHaren Myneni4-1/+220
When NX encounters translation error on CRB and any request buffer, raises an interrupt on the CPU to handle the fault. It can raise one interrupt for multiple faults. Expects OS to handle these faults and return credits for fault window after processing faults. Setup thread IRQ handler and IRQ thread function per each VAS instance. IRQ handler checks if the thread is already woken up and can handle new faults. If so returns with IRQ_HANDLED, otherwise wake up thread to process new faults. The thread functions reads each CRB entry from fault FIFO until sees invalid entry. After reading each CRB, determine the corresponding send window using pswid (from CRB) and process fault CRB. Then invalidate the entry and return credit. Processing fault CRB and return credit is described in subsequent patches. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587016982.2275.1060.camel@hbabu-laptop
2020-04-20powerpc/vas: Take reference to PID and mm for user space windowsHaren Myneni3-6/+55
When process opens a window, its pid and tgid will be saved in the vas_window struct. This window will be closed when the process exits. The kernel handles NX faults by updating CSB or send SEGV signal to pid of the process if the userspace csb addr is invalid. In multi-thread applications, a window can be opened by a child thread, but it will not be closed when this thread exits. It is expected that the parent will clean up all resources including NX windows opened by child threads. A child thread can send NX requests using this window and could be killed before completion is reported. If the pid assigned to this thread is reused while requests are pending, a failure SEGV would be directed to the wrong place. To prevent reusing the pid, take references to pid and mm when the window is opened and release them when when the window is closed. Then if child thread is not running, SEGV signal will be sent to thread group leader (tgid). Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587016936.2275.1057.camel@hbabu-laptop
2020-04-20powerpc/vas: Register NX with fault window ID and IRQ port valueHaren Myneni2-2/+28
For each user space send window, register NX with fault window ID and port value so that NX paste CRBs in this fault FIFO when it sees fault on the request buffer. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587016888.2275.1054.camel@hbabu-laptop
2020-04-20powerpc/vas: Setup fault window per VAS instanceHaren Myneni5-3/+121
Setup fault window for each VAS instance. When NX gets a fault on request buffer, pastes fault CRB in the corresponding fault FIFO and then raises an interrupt to the OS. The kernel handles this fault and process faults CRB from this FIFO. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587016846.2275.1053.camel@hbabu-laptop
2020-04-20powerpc/vas: Alloc and setup IRQ and trigger port addressHaren Myneni2-6/+40
Allocate a xive irq on each chip with a vas instance. The NX coprocessor raises a host CPU interrupt via vas if it encounters page fault on user space request buffer. Subsequent patches register the trigger port with the NX coprocessor, and create a vas fault handler for this interrupt mapping. Signed-off-by: Haren Myneni <haren@linux.ibm.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587016806.2275.1050.camel@hbabu-laptop
2020-04-09Merge tag 'powerpc-5.7-2' of ↵Linus Torvalds4-11/+22
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull more powerpc updates from Michael Ellerman: "The bulk of this is the series to make CONFIG_COMPAT user-selectable, it's been around for a long time but was blocked behind the syscall-in-C series. Plus there's also a few fixes and other minor things. Summary: - A fix for a crash in machine check handling on pseries (ie. guests) - A small series to make it possible to disable CONFIG_COMPAT, and turn it off by default for ppc64le where it's not used. - A few other miscellaneous fixes and small improvements. Thanks to: Alexey Kardashevskiy, Anju T Sudhakar, Arnd Bergmann, Christophe Leroy, Dan Carpenter, Ganesh Goudar, Geert Uytterhoeven, Geoff Levand, Mahesh Salgaonkar, Markus Elfring, Michal Suchanek, Nicholas Piggin, Stephen Boyd, Wen Xiong" * tag 'powerpc-5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: selftests/powerpc: Always build the tm-poison test 64-bit powerpc: Improve ppc_save_regs() Revert "powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled" powerpc/time: Replace <linux/clk-provider.h> by <linux/of_clk.h> powerpc/pseries/ddw: Extend upper limit for huge DMA window for persistent memory powerpc/perf: split callchain.c by bitness powerpc/64: Make COMPAT user-selectable disabled on littleendian by default. powerpc/64: make buildable without CONFIG_COMPAT powerpc/perf: consolidate valid_user_sp -> invalid_user_sp powerpc/perf: consolidate read_user_stack_32 powerpc: move common register copy functions from signal_32.c to signal.c powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro powerpc/ps3: Set CONFIG_UEVENT_HELPER=y in ps3_defconfig powerpc/ps3: Remove an unneeded NULL check powerpc/ps3: Remove duplicate error message powerpc/powernv: Re-enable imc trace-mode in kernel powerpc/perf: Implement a global lock to avoid races between trace, core and thread imc events. powerpc/pseries: Fix MCE handling on pseries selftests/eeh: Skip ahci adapters powerpc/64s: Fix doorbell wakeup msgclr optimisation
2020-04-09Merge tag 'libnvdimm-for-5.7' of ↵Linus Torvalds1-22/+5
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm and dax updates from Dan Williams: "There were multiple touches outside of drivers/nvdimm/ this round to add cross arch compatibility to the devm_memremap_pages() interface, enhance numa information for persistent memory ranges, and add a zero_page_range() dax operation. This cycle I switched from the patchwork api to Konstantin's b4 script for collecting tags (from x86, PowerPC, filesystem, and device-mapper folks), and everything looks to have gone ok there. This has all appeared in -next with no reported issues. Summary: - Add support for region alignment configuration and enforcement to fix compatibility across architectures and PowerPC page size configurations. - Introduce 'zero_page_range' as a dax operation. This facilitates filesystem-dax operation without a block-device. - Introduce phys_to_target_node() to facilitate drivers that want to know resulting numa node if a given reserved address range was onlined. - Advertise a persistence-domain for of_pmem and papr_scm. The persistence domain indicates where cpu-store cycles need to reach in the platform-memory subsystem before the platform will consider them power-fail protected. - Promote numa_map_to_online_node() to a cross-kernel generic facility. - Save x86 numa information to allow for node-id lookups for reserved memory ranges, deploy that capability for the e820-pmem driver. - Pick up some miscellaneous minor fixes, that missed v5.6-final, including a some smatch reports in the ioctl path and some unit test compilation fixups. - Fixup some flexible-array declarations" * tag 'libnvdimm-for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (29 commits) dax: Move mandatory ->zero_page_range() check in alloc_dax() dax,iomap: Add helper dax_iomap_zero() to zero a range dax: Use new dax zero page method for zeroing a page dm,dax: Add dax zero_page_range operation s390,dcssblk,dax: Add dax zero_page_range operation to dcssblk driver dax, pmem: Add a dax operation zero_page_range pmem: Add functions for reading/writing page to/from pmem libnvdimm: Update persistence domain value for of_pmem and papr_scm device tools/test/nvdimm: Fix out of tree build libnvdimm/region: Fix build error libnvdimm/region: Replace zero-length array with flexible-array member libnvdimm/label: Replace zero-length array with flexible-array member ACPI: NFIT: Replace zero-length array with flexible-array member libnvdimm/region: Introduce an 'align' attribute libnvdimm/region: Introduce NDD_LABELING libnvdimm/namespace: Enforce memremap_compat_align() libnvdimm/pfn: Prevent raw mode fallback if pfn-infoblock valid libnvdimm: Out of bounds read in __nd_ioctl() acpi/nfit: improve bounds checking for 'func' mm/memremap_pages: Introduce memremap_compat_align() ...
2020-04-07powernv/memtrace: always online added memory blocksDavid Hildenbrand1-10/+4
Let's always try to online the re-added memory blocks. In case add_memory() already onlined the added memory blocks, the first device_online() call will fail and stop processing the remaining memory blocks. This avoids manually having to check memhp_auto_online. Note: PPC always onlines all hotplugged memory directly from the kernel as well - something that is handled by user space on other architectures. Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Baoquan He <bhe@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wei Liu <wei.liu@kernel.org> Cc: Yumei Huang <yuhuang@redhat.com> Link: http://lkml.kernel.org/r/20200317104942.11178-5-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-05Merge tag 'powerpc-5.7-1' of ↵Linus Torvalds32-224/+227
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: "Slightly late as I had to rebase mid-week to insert a bug fix: - A large series from Nick for 64-bit to further rework our exception vectors, and rewrite portions of the syscall entry/exit and interrupt return in C. The result is much easier to follow code that is also faster in general. - Cleanup of our ptrace code to split various parts out that had become badly intertwined with #ifdefs over the years. - Changes to our NUMA setup under the PowerVM hypervisor which should hopefully avoid non-sensical topologies which can lead to warnings from the workqueue code and other problems. - MAINTAINERS updates to remove some of our old orphan entries and update the status of others. - Quite a few other small changes and fixes all over the map. Thanks to: Abdul Haleem, afzal mohammed, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Balamuruhan S, Cédric Le Goater, Chen Zhou, Christophe JAILLET, Christophe Leroy, Christoph Hellwig, Clement Courbet, Daniel Axtens, David Gibson, Douglas Miller, Fabiano Rosas, Fangrui Song, Ganesh Goudar, Gautham R. Shenoy, Greg Kroah-Hartman, Greg Kurz, Gustavo Luiz Duarte, Hari Bathini, Ilie Halip, Jan Kara, Joe Lawrence, Joe Perches, Kajol Jain, Larry Finger, Laurentiu Tudor, Leonardo Bras, Libor Pechacek, Madhavan Srinivasan, Mahesh Salgaonkar, Masahiro Yamada, Masami Hiramatsu, Mauricio Faria de Oliveira, Michael Neuling, Michal Suchanek, Mike Rapoport, Nageswara R Sastry, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Po-Hsu Lin, Pratik Rajesh Sampat, Rasmus Villemoes, Ravi Bangoria, Roman Bolshakov, Sam Bobroff, Sandipan Das, Santosh S, Sedat Dilek, Segher Boessenkool, Shilpasri G Bhat, Sourabh Jain, Srikar Dronamraju, Stephen Rothwell, Tyrel Datwyler, Vaibhav Jain, YueHaibing" * tag 'powerpc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits) powerpc: Make setjmp/longjmp signature standard powerpc/cputable: Remove unnecessary copy of cpu_spec->oprofile_type powerpc: Suppress .eh_frame generation powerpc: Drop -fno-dwarf2-cfi-asm powerpc/32: drop unused ISA_DMA_THRESHOLD powerpc/powernv: Add documentation for the opal sensor_groups sysfs interfaces selftests/powerpc: Fix try-run when source tree is not writable powerpc/vmlinux.lds: Explicitly retain .gnu.hash powerpc/ptrace: move ptrace_triggered() into hw_breakpoint.c powerpc/ptrace: create ppc_gethwdinfo() powerpc/ptrace: create ptrace_get_debugreg() powerpc/ptrace: split out ADV_DEBUG_REGS related functions. powerpc/ptrace: move register viewing functions out of ptrace.c powerpc/ptrace: split out TRANSACTIONAL_MEM related functions. powerpc/ptrace: split out SPE related functions. powerpc/ptrace: split out ALTIVEC related functions. powerpc/ptrace: split out VSX related functions. powerpc/ptrace: drop PARAMETER_SAVE_AREA_OFFSET powerpc/ptrace: drop unnecessary #ifdefs CONFIG_PPC64 powerpc/ptrace: remove unused header includes ...
2020-04-03Merge tag 'spdx-5.7-rc1' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx Pull SPDX updates from Greg KH: "Here are three SPDX patches for 5.7-rc1. One fixes up the SPDX tag for a single driver, while the other two go through the tree and add SPDX tags for all of the .gitignore files as needed. Nothing too complex, but you will get a merge conflict with your current tree, that should be trivial to handle (one file modified by two things, one file deleted.) All three of these have been in linux-next for a while, with no reported issues other than the merge conflict" * tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: ASoC: MT6660: make spdxcheck.py happy .gitignore: add SPDX License Identifier .gitignore: remove too obvious comments
2020-04-03Merge branch 'for-5.7/libnvdimm' into libnvdimm-for-nextDan Williams1-1/+3
- Introduce 'zero_page_range' as a dax operation. This facilitates filesystem-dax operation without a block-device. - Advertise a persistence-domain for of_pmem and papr_scm. The persistence domain indicates where cpu-store cycles need to reach in the platform-memory subsystem before the platform will consider them power-fail protected. - Fixup some flexible-array declarations.
2020-04-03Merge branch 'for-5.7/numa' into libnvdimm-for-nextDan Williams1-20/+1
- Promote numa_map_to_online_node() to a cross-kernel generic facility. - Save x86 numa information to allow for node-id lookups for reserved memory ranges, deploy that capability for the e820-pmem driver. - Introduce phys_to_target_node() to facilitate drivers that want to know resulting numa node if a given reserved address range was onlined.
2020-04-03powerpc/pseries/ddw: Extend upper limit for huge DMA window for persistent ↵Alexey Kardashevskiy1-0/+9
memory Unlike normal memory ("memory" compatible type in the FDT), the persistent memory ("ibm,pmemory" in the FDT) can be mapped anywhere in the guest physical space and it can be used for DMA. In order to maintain 1:1 mapping via the huge DMA window, we need to know the maximum physical address at the time of the window setup. So far we've been looking at "memory" nodes but "ibm,pmemory" does not have fixed addresses and the persistent memory may be mapped afterwards. Since the persistent memory is still backed with page structs, use MAX_PHYSMEM_BITS as the upper limit. This effectively disables huge DMA window in LPAR under pHyp if persistent memory is present but this is the best we can do for the moment. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Tested-by: Wen Xiong<wenxiong@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200331012338.23773-1-aik@ozlabs.ru
2020-04-02mm/sparse: rename pfn_present() to pfn_in_present_section()Pingfan Liu1-1/+1
After introducing mem sub section concept, pfn_present() loses its literal meaning, and will not be necessary a truth on partial populated mem section. Since all of the callers use it to judge an absent section, it is better to rename pfn_present() as pfn_in_present_section(). Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Leonardo Bras <leonardo@linux.ibm.com> Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Link: http://lkml.kernel.org/r/1581919110-29575-1-git-send-email-kernelfans@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02powerpc/ps3: Remove duplicate error messageMarkus Elfring1-3/+1
Remove a duplicate memory allocation failure error message. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Geoff Levand <geoff@infradead.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1bc5a16a22c487c478a204ebb7b80a22d2ad9cd0.1585340156.git.geoff@infradead.org
2020-04-02powerpc/powernv: Re-enable imc trace-mode in kernelAnju T Sudhakar1-8/+1
commit <249fad734a25> ""powerpc/perf: Disable trace_imc pmu" disables IMC(In-Memory Collection) trace-mode in kernel, since frequent mode switching between accumulation mode and trace mode via the spr LDBAR in the hardware can trigger a checkstop(system crash). Patch to re-enable imc-trace mode in kernel. The previous patch(1/2) in this series will address the mode switching issue by implementing a global lock, and will restrict the usage of accumulation and trace-mode at a time. Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200313055238.8656-2-anju@linux.vnet.ibm.com
2020-04-02powerpc/pseries: Fix MCE handling on pseriesGanesh Goudar1-0/+11
MCE handling on pSeries platform fails as recent rework to use common code for pSeries and PowerNV in machine check error handling tries to access per-cpu variables in realmode. The per-cpu variables may be outside the RMO region on pSeries platform and needs translation to be enabled for access. Just moving these per-cpu variable into RMO region did'nt help because we queue some work to workqueues in real mode, which again tries to touch per-cpu variables. Also fwnmi_release_errinfo() cannot be called when translation is not enabled. This patch fixes this by enabling translation in the exception handler when all required real mode handling is done. This change only affects the pSeries platform. Without this fix below kernel crash is seen on injecting SLB multihit: BUG: Unable to handle kernel data access on read at 0xc00000027b205950 Faulting instruction address: 0xc00000000003b7e0 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: mcetest_slb(OE+) af_packet(E) xt_tcpudp(E) ip6t_rpfilter(E) ip6t_REJECT(E) ipt_REJECT(E) xt_conntrack(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) ip6table_nat(E) ip6table_mangle(E) ip6table_raw(E) ip6table_security(E) iptable_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E) ip_tables(E) x_tables(E) xfs(E) ibmveth(E) vmx_crypto(E) gf128mul(E) uio_pdrv_genirq(E) uio(E) crct10dif_vpmsum(E) rtc_generic(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) raid6_pq(E) sr_mod(E) sd_mod(E) cdrom(E) ibmvscsi(E) scsi_transport_srp(E) crc32c_vpmsum(E) dm_mod(E) sg(E) scsi_mod(E) CPU: 34 PID: 8154 Comm: insmod Kdump: loaded Tainted: G OE 5.5.0-mahesh #1 NIP: c00000000003b7e0 LR: c0000000000f2218 CTR: 0000000000000000 REGS: c000000007dcb960 TRAP: 0300 Tainted: G OE (5.5.0-mahesh) MSR: 8000000000001003 <SF,ME,RI,LE> CR: 28002428 XER: 20040000 CFAR: c0000000000f2214 DAR: c00000027b205950 DSISR: 40000000 IRQMASK: 0 GPR00: c0000000000f2218 c000000007dcbbf0 c000000001544800 c000000007dcbd70 GPR04: 0000000000000001 c000000007dcbc98 c008000000d00258 c0080000011c0000 GPR08: 0000000000000000 0000000300000003 c000000001035950 0000000003000048 GPR12: 000000027a1d0000 c000000007f9c000 0000000000000558 0000000000000000 GPR16: 0000000000000540 c008000001110000 c008000001110540 0000000000000000 GPR20: c00000000022af10 c00000025480fd70 c008000001280000 c00000004bfbb300 GPR24: c000000001442330 c00800000800000d c008000008000000 4009287a77000510 GPR28: 0000000000000000 0000000000000002 c000000001033d30 0000000000000001 NIP [c00000000003b7e0] save_mce_event+0x30/0x240 LR [c0000000000f2218] pseries_machine_check_realmode+0x2c8/0x4f0 Call Trace: Instruction dump: 3c4c0151 38429050 7c0802a6 60000000 fbc1fff0 fbe1fff8 f821ffd1 3d42ffaf 3fc2ffaf e98d0030 394a1150 3bdef530 <7d6a62aa> 1d2b0048 2f8b0063 380b0001 ---[ end trace 46fd63f36bbdd940 ]--- Fixes: 9ca766f9891d ("powerpc/64s/pseries: machine check convert to use common event code") Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200320110119.10207-1-ganeshgr@linux.ibm.com
2020-04-01powerpc/32: drop unused ISA_DMA_THRESHOLDMike Rapoport5-7/+0
The ISA_DMA_THRESHOLD variable is set by several platforms but never referenced. Remove it. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191125092033.20014-1-rppt@kernel.org
2020-04-01libnvdimm: Update persistence domain value for of_pmem and papr_scm deviceAneesh Kumar K.V1-1/+3
Currently, kernel shows the below values "persistence_domain":"cpu_cache" "persistence_domain":"memory_controller" "persistence_domain":"unknown" "cpu_cache" indicates no extra instructions is needed to ensure the persistence of data in the pmem media on power failure. "memory_controller" indicates cpu cache flush instructions are required to flush the data. Platform provides mechanisms to automatically flush outstanding write data from memory controler to pmem on system power loss. Based on the above use memory_controller for non volatile regions on ppc64. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Link: https://lore.kernel.org/r/20200324034821.60869-1-aneesh.kumar@linux.ibm.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2020-03-27powerpc/pseries: Handle UE event for memcpy_mcsafeGanesh Goudar1-0/+3
memcpy_mcsafe has been implemented for power machines which is used by pmem infrastructure, so that an UE encountered during memcpy from pmem devices would not result in panic instead a right error code is returned. The implementation expects machine check handler to ignore the event and set nip to continue the execution from fixup code. Appropriate changes are already made to powernv machine check handler, make similar changes to pseries machine check handler to ignore the the event and set nip to continue execution at the fixup entry if we hit UE at an instruction with a fixup entry. while we are at it, have a common function which searches the exception table entry and updates nip with fixup address, and any future common changes can be made in this function that are valid for both architectures. powernv changes are made by commit 895e3dceeb97 ("powerpc/mce: Handle UE event for memcpy_mcsafe") Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Reviewed-by: Santosh S <santosh@fossix.org> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200326184916.31172-1-ganeshgr@linux.ibm.com
2020-03-25.gitignore: add SPDX License IdentifierMasahiro Yamada1-0/+1
Add SPDX License Identifier to all .gitignore files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-25powerpc/maple: Fix declaration made after definitionNathan Chancellor1-17/+17
When building ppc64 defconfig, Clang errors (trimmed for brevity): arch/powerpc/platforms/maple/setup.c:365:1: error: attribute declaration must precede definition [-Werror,-Wignored-attributes] machine_device_initcall(maple, maple_cpc925_edac_setup); ^ machine_device_initcall expands to __define_machine_initcall, which in turn has the macro machine_is used in it, which declares mach_##name with an __attribute__((weak)). define_machine actually defines mach_##name, which in this file happens before the declaration, hence the warning. To fix this, move define_machine after machine_device_initcall so that the declaration occurs before the definition, which matches how machine_device_initcall and define_machine work throughout arch/powerpc. While we're here, remove some spaces before tabs. Fixes: 8f101a051ef0 ("edac: cpc925 MC platform device setup") Reported-by: Nick Desaulniers <ndesaulniers@google.com> Suggested-by: Ilie Halip <ilie.halip@gmail.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200323222729.15365-1-natechancellor@gmail.com
2020-03-25powerpc/pseries: Avoid harmless preempt warningNicholas Piggin1-1/+9
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200320152436.1468651-1-npiggin@gmail.com
2020-03-25powerpc/eeh: Rework eeh_ops->probe()Oliver O'Halloran2-17/+36
With the EEH early probe now being pseries specific there's no need for eeh_ops->probe() to take a pci_dn. Instead, we can make it take a pci_dev and use the probe function to map a pci_dev to an eeh_dev. This allows the platform to implement it's own method for finding (or creating) an eeh_dev for a given pci_dev which also removes a use of pci_dn in generic EEH code. This patch also renames eeh_device_add_late() to eeh_device_probe(). This better reflects what it does does and removes the last vestiges of the early/late EEH probe split. Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com> Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200306073904.4737-6-oohall@gmail.com
2020-03-25powerpc/eeh: Make early EEH init pseries specificOliver O'Halloran3-21/+52
The eeh_ops->probe() function is called from two different contexts: 1. On pseries, where we set EEH_PROBE_MODE_DEVTREE, it's called in eeh_add_device_early() which is supposed to run before we create a pci_dev. 2. On PowerNV, where we set EEH_PROBE_MODE_DEV, it's called in eeh_device_add_late() which is supposed to run *after* the pci_dev is created. The "early" probe is required because PAPR requires that we perform an RTAS call to enable EEH support on a device before we start interacting with it via config space or MMIO. This requirement doesn't exist on PowerNV and shoehorning two completely separate initialisation paths into a common interface just results in a convoluted code everywhere. Additionally the early probe requires the probe function to take an pci_dn rather than a pci_dev argument. We'd like to make pci_dn a pseries specific data structure since there's no real requirement for them on PowerNV. To help both goals move the early probe into the pseries containment zone so the platform depedence is more explicit. Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com> Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200306073904.4737-5-oohall@gmail.com
2020-03-25powerpc/eeh: Add sysfs files in late probeOliver O'Halloran2-3/+1
Move creating the EEH specific sysfs files into eeh_add_device_late() rather than being open-coded all over the place. Calling the function is generally done immediately after calling eeh_add_device_late() anyway. This is also a correctness fix since currently the sysfs files will be added even if the EEH probe happens to fail. Similarly, on pseries we currently add the sysfs files before calling eeh_add_device_late(). This is flat-out broken since the sysfs files require the pci_dev->dev.archdata.edev pointer to be set, and that is done in eeh_add_device_late(). Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com> Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200306073904.4737-1-oohall@gmail.com
2020-03-25powerpc: Replace setup_irq() by request_irq()afzal mohammed6-55/+29
request_irq() is preferred over setup_irq(). Invocations of setup_irq() occur after memory allocators are ready. Per tglx[1], setup_irq() existed in olden days when allocators were not ready by the time early interrupts were initialized. Hence replace setup_irq() by request_irq(). [1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200312064256.18735-1-afzal.mohd.ma@gmail.com
2020-03-25powerpc/cell: Use fallthrough;Joe Perches1-1/+1
Convert the various uses of fallthrough comments to fallthrough; Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/03073a9a269010ca439e9e658629c44602b0cc9f.1583896348.git.joe@perches.com
2020-03-25powerpc/pseries: Fix of_read_drc_info_cell() to point at next recordTyrel Datwyler1-1/+1
The expectation is that when calling of_read_drc_info_cell() repeatedly to parse multiple drc-info records that the in/out curval parameter points at the start of the next record on return. However, the current behavior has curval still pointing at the final value of the record just parsed. The result of which is that if the ibm,drc-info property contains multiple properties the parsed value of the drc_type for any record after the first has the power_domain value of the previous record appended to the type string. eg: observed the following 0xffffffff prepended to PHB drc-info: type: \xff\xff\xff\xffPHB, prefix: PHB , index_start: 0x20000001 drc-info: suffix_start: 1, sequential_elems: 3072, sequential_inc: 1 drc-info: power-domain: 0xffffffff, last_index: 0x20000c00 In practice PHBs are the only type of connector in the ibm,drc-info property that has multiple records. So, it breaks PHB hotplug, but by chance not PCI, CPU, slot, or memory because they happen to only ever be a single record. Fix by incrementing curval past the power_domain value to point at drc_type string of next record. Fixes: e83636ac3334 ("pseries/drc-info: Search DRC properties for CPU indexes") Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> Acked-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200307024547.5748-1-tyreld@linux.ibm.com
2020-03-21powerpc/ps3: Convert half completion to rcuwaitPeter Zijlstra (Intel)1-9/+9
The PS3 notification interrupt and kthread use a hacked up completion to communicate. Since we're wanting to change the completion implementation and this is abuse anyway, replace it with a simple rcuwait since there is only ever the one waiter. AFAICT the kthread uses TASK_INTERRUPTIBLE to not increase loadavg, kthreads cannot receive signals by default and this one doesn't look different. Use TASK_IDLE instead. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113241.930037873@linutronix.de
2020-03-20powerpc/kuap: PPC_KUAP_DEBUG should depend on PPC_KUAPMichael Ellerman1-1/+1
Currently you can enable PPC_KUAP_DEBUG when PPC_KUAP is disabled, even though the former has not effect without the latter. Fix it so that PPC_KUAP_DEBUG can only be enabled when PPC_KUAP is enabled, not when the platform could support KUAP (PPC_HAVE_KUAP). Fixes: 890274c2dc4c ("powerpc/64s: Implement KUAP for Radix MMU") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200301111738.22497-1-mpe@ellerman.id.au
2020-03-17libnvdimm/region: Introduce NDD_LABELINGDan Williams1-1/+1
The NDD_ALIASING flag is used to indicate where pmem capacity might alias with blk capacity and require labeling. It is also used to indicate whether the DIMM supports labeling. Separate this latter capability into its own flag so that the NDD_ALIASING flag is scoped to true aliased configurations. To my knowledge aliased configurations only exist in the ACPI spec, there are no known platforms that ship this support in production. This clarity allows namespace-capacity alignment constraints around interleave-ways to be relaxed. Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Oliver O'Halloran <oohall@gmail.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Link: https://lore.kernel.org/r/158041477856.3889308.4212605617834097674.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2020-03-17powerpc/pmac/smp: Drop unnecessary volatile qualifierYueHaibing1-2/+2
core99_l2_cache/core99_l3_cache do not need to be marked as volatile, remove it. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200303085604.24952-1-yuehaibing@huawei.com
2020-03-17powerpc/pmac/smp: Avoid unused-variable warningsIlie Halip1-4/+4
When building with ppc64_defconfig, the compiler reports that these 2 variables are not used: warning: unused variable 'core99_l2_cache' [-Wunused-variable] warning: unused variable 'core99_l3_cache' [-Wunused-variable] They are only used when CONFIG_PPC64 is not defined. Move them into a section which does the same macro check. Reported-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Ilie Halip <ilie.halip@gmail.com> [mpe: Move them into core99_init_caches() which is their only user] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190920153951.25762-1-ilie.halip@gmail.com
2020-03-04powerpc/vphn: Check for error from hcall_vphnSrikar Dronamraju1-1/+2
There is no value in unpacking associativity, if H_HOME_NODE_ASSOCIATIVITY hcall has returned an error. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200129135301.24739-2-srikar@linux.vnet.ibm.com
2020-03-04powerpc/kernel/sysfs: Add new config option PMU_SYSFS to enable PMU SPRs ↵Kajol Jain1-0/+6
sysfs file creation Many of the performance monitoring unit (PMU) SPRs are exposed in the sysfs. This may not be a desirable since "perf" API is the primary interface to program PMU and collect counter data in the system. But that said, we cant remove these sysfs files since we dont whether anyone/anything is using them. So the patch adds a new CONFIG option 'CONFIG_PMU_SYSFS' (user selectable) to be used in sysfs file creation for PMU SPRs. New option by default is disabled, but can be enabled if user needs it. Tested this patch behaviour in powernv and pseries machines. Patch is also tested for pmac32_defconfig. Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Tested-by: Nageswara R Sastry <nasastry@in.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200214080606.26872-2-kjain@linux.ibm.com
2020-03-04powerpc/powernv: Add explicit fast-reboot supportOliver O'Halloran1-0/+2
Add a way to manually invoke a fast-reboot rather than setting the NVRAM flag. The idea is to allow userspace to invoke a fast-reboot using the optional string argument to the reboot() system call, or using the xmon zr command so we don't need to leave around a persistent changes on a system to use the feature. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200217024833.30580-2-oohall@gmail.com
2020-03-04powerpc/powernv: Treat an empty reboot string as defaultOliver O'Halloran1-1/+1
Treat an empty reboot cmd string the same as a NULL string. This squashes a spurious unsupported reboot message that sometimes gets out when using xmon. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200217024833.30580-1-oohall@gmail.com
2020-03-04powerpc/powernv: no need to check return value of debugfs_create functionsGreg Kroah-Hartman4-63/+10
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200209105901.1620958-6-gregkh@linuxfoundation.org
2020-03-04powerpc/cell/axon_msi: no need to check return value of debugfs_create functionsGreg Kroah-Hartman1-5/+1
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200209105901.1620958-5-gregkh@linuxfoundation.org
2020-03-04powerpc/83xx: Add some error handling in 'quirk_mpc8360e_qe_enet10()'Christophe JAILLET1-1/+4
In some error handling path, we should call "of_node_put(np_par)" or some resource may be leaking in case of error. Fixes: 8159df72d43e ("83xx: add support for the kmeter1 board.") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Acked-by: Scott Wood <oss@buserror.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200208140920.7652-1-christophe.jaillet@wanadoo.fr
2020-03-04powerpc/83xx: Fix some typo in some warning messageChristophe JAILLET1-2/+2
"couldn;t" should be "couldn't". Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Acked-by: Scott Wood <oss@buserror.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200208140904.7521-1-christophe.jaillet@wanadoo.fr
2020-02-19powerpc/pseries: Avoid NULL pointer dereference when drmem is unavailableLibor Pechacek1-4/+4
In guests without hotplugagble memory drmem structure is only zero initialized. Trying to manipulate DLPAR parameters results in a crash. $ echo "memory add count 1" > /sys/kernel/dlpar Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries ... NIP: c0000000000ff294 LR: c0000000000ff248 CTR: 0000000000000000 REGS: c0000000fb9d3880 TRAP: 0300 Tainted: G E (5.5.0-rc6-2-default) MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 28242428 XER: 20000000 CFAR: c0000000009a6c10 DAR: 0000000000000010 DSISR: 40000000 IRQMASK: 0 ... NIP dlpar_memory+0x6e4/0xd00 LR dlpar_memory+0x698/0xd00 Call Trace: dlpar_memory+0x698/0xd00 (unreliable) handle_dlpar_errorlog+0xc0/0x190 dlpar_store+0x198/0x4a0 kobj_attr_store+0x30/0x50 sysfs_kf_write+0x64/0x90 kernfs_fop_write+0x1b0/0x290 __vfs_write+0x3c/0x70 vfs_write+0xd0/0x260 ksys_write+0xdc/0x130 system_call+0x5c/0x68 Taking closer look at the code, I can see that for_each_drmem_lmb is a macro expanding into `for (lmb = &drmem_info->lmbs[0]; lmb <= &drmem_info->lmbs[drmem_info->n_lmbs - 1]; lmb++)`. When drmem_info->lmbs is NULL, the loop would iterate through the whole address range if it weren't stopped by the NULL pointer dereference on the next line. This patch aligns for_each_drmem_lmb and for_each_drmem_lmb_in_range macro behavior with the common C semantics, where the end marker does not belong to the scanned range, and alters get_lmb_range() semantics. As a side effect, the wraparound observed in the crash is prevented. Fixes: 6c6ea53725b3 ("powerpc/mm: Separate ibm, dynamic-memory data from DT format") Cc: stable@vger.kernel.org # v4.16+ Signed-off-by: Libor Pechacek <lpechacek@suse.cz> Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200131132829.10281-1-msuchanek@suse.de