- 21 Dec, 2018 40 commits
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Alexey Kardashevskiy authored
POWER9 Witherspoon machines come with 4 or 6 V100 GPUs which are not pluggable PCIe devices but still have PCIe links which are used for config space and MMIO. In addition to that the GPUs have 6 NVLinks which are connected to other GPUs and the POWER9 CPU. POWER9 chips have a special unit on a die called an NPU which is an NVLink2 host bus adapter with p2p connections to 2 to 3 GPUs, 3 or 2 NVLinks to each. These systems also support ATS (address translation services) which is a part of the NVLink2 protocol. Such GPUs also share on-board RAM (16GB or 32GB) to the system via the same NVLink2 so a CPU has cache-coherent access to a GPU RAM. This exports GPU RAM to the userspace as a new VFIO device region. This preregisters the new memory as device memory as it might be used for DMA. This inserts pfns from the fault handler as the GPU memory is not onlined until the vendor driver is loaded and trained the NVLinks so doing this earlier causes low level errors which we fence in the firmware so it does not hurt the host system but still better be avoided; for the same reason this does not map GPU RAM into the host kernel (usual thing for emulated access otherwise). This exports an ATSD (Address Translation Shootdown) register of NPU which allows TLB invalidations inside GPU for an operating system. The register conveniently occupies a single 64k page. It is also presented to the userspace as a new VFIO device region. One NPU has 8 ATSD registers, each of them can be used for TLB invalidation in a GPU linked to this NPU. This allocates one ATSD register per an NVLink bridge allowing passing up to 6 registers. Due to the host firmware bug (just recently fixed), only 1 ATSD register per NPU was actually advertised to the host system so this passes that alone register via the first NVLink bridge device in the group which is still enough as QEMU collects them all back and presents to the guest via vPHB to mimic the emulated NPU PHB on the host. In order to provide the userspace with the information about GPU-to-NVLink connections, this exports an additional capability called "tgt" (which is an abbreviated host system bus address). The "tgt" property tells the GPU its own system address and allows the guest driver to conglomerate the routing information so each GPU knows how to get directly to the other GPUs. For ATS to work, the nest MMU (an NVIDIA block in a P9 CPU) needs to know LPID (a logical partition ID or a KVM guest hardware ID in other words) and PID (a memory context ID of a userspace process, not to be confused with a linux pid). This assigns a GPU to LPID in the NPU and this is why this adds a listener for KVM on an IOMMU group. A PID comes via NVLink from a GPU and NPU uses a PID wildcard to pass it through. This requires coherent memory and ATSD to be available on the host as the GPU vendor only supports configurations with both features enabled and other configurations are known not to work. Because of this and because of the ways the features are advertised to the host system (which is a device tree with very platform specific properties), this requires enabled POWERNV platform. The V100 GPUs do not advertise any of these capabilities via the config space and there are more than just one device ID so this relies on the platform to tell whether these GPUs have special abilities such as NVLinks. Signed-off-by:
Alexey Kardashevskiy <aik@ozlabs.ru> Acked-by:
Alex Williamson <alex.williamson@redhat.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Alexey Kardashevskiy authored
VFIO regions already support region capabilities with a limited set of fields. However the subdriver might have to report to the userspace additional bits. This adds an add_capability() hook to vfio_pci_regops. Signed-off-by:
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Alexey Kardashevskiy authored
So far we only allowed mapping of MMIO BARs to the userspace. However there are GPUs with on-board coherent RAM accessible via side channels which we also want to map to the userspace. The first client for this is NVIDIA V100 GPU with NVLink2 direct links to a POWER9 NPU-enabled CPU; such GPUs have 16GB RAM which is coherently mapped to the system address space, we are going to export these as an extra PCI region. We already support extra PCI regions and this adds support for mapping them to the userspace. Signed-off-by:
David Gibson <david@gibson.dropbear.id.au> Acked-by:
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Alexey Kardashevskiy authored
When a page fault happens in a GPU, the GPU signals the OS and the GPU driver calls the fault handler which populated a page table; this allows the GPU to complete an ATS request. On the bare metal get_user_pages() is enough as it adds a pte to the kernel page table but under KVM the partition scope tree does not get updated so ATS will still fail. This reads a byte from an effective address which causes HV storage interrupt and KVM updates the partition scope tree. Signed-off-by:
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Alexey Kardashevskiy authored
A broken device tree might contain more than 8 values and introduce hard to debug memory corruption bug. This adds the boundary check. Signed-off-by:
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Alexey Kardashevskiy authored
In order to make ATS work and translate addresses for arbitrary LPID and PID, we need to program an NPU with LPID and allow PID wildcard matching with a specific MSR mask. This implements a helper to assign a GPU to LPAR and program the NPU with a wildcard for PID and a helper to do clean-up. The helper takes MSR (only DR/HV/PR/SF bits are allowed) to program them into NPU2 for ATS checkout requests support. This exports pnv_npu2_unmap_lpar_dev() as following patches will use it from the VFIO driver. Signed-off-by:
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Alexey Kardashevskiy authored
At the moment the powernv platform registers an IOMMU group for each PE. There is an exception though: an NVLink bridge which is attached to the corresponding GPU's IOMMU group making it a master. Now we have POWER9 systems with GPUs connected to each other directly bypassing PCI. At the moment we do not control state of these links so we have to put such interconnected GPUs to one IOMMU group which means that the old scheme with one GPU as a master won't work - there will be up to 3 GPUs in such group. This introduces a npu_comp struct which represents a compound IOMMU group made of multiple PEs - PCI PEs (for GPUs) and NPU PEs (for NVLink bridges). This converts the existing NVLink1 code to use the new scheme. >From now on, each PE must have a valid iommu_table_group_ops which will either be called directly (for a single PE group) or indirectly from a compound group handlers. This moves IOMMU group registration for NVLink-connected GPUs to npu-dma.c. For POWER8, this stores a new compound group pointer in the PE (so a GPU is still a master); for POWER9 the new group pointer is stored in an NPU (which is allocated per a PCI host controller). Signed-off-by:
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Alexey Kardashevskiy authored
At the moment NPU IOMMU is manipulated directly from the IODA2 PCI PE code; PCI PE acts as a master to NPU PE. Soon we will have compound IOMMU groups with several PEs from several different PHB (such as interconnected GPUs and NPUs) so there will be no single master but a one big IOMMU group. This makes a first step and converts an NPU PE with a set of extern function to a table group. This should cause no behavioral change. Note that pnv_npu_release_ownership() has never been implemented. Signed-off-by:
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Alexey Kardashevskiy authored
Normal PCI PEs have 2 TVEs, one per a DMA window; however NPU PE has only one which points to one of two tables of the corresponding PCI PE. So whenever a new DMA window is programmed to PEs, the NPU PE needs to release old table in order to use the new one. Commit d41ce7b1 ("powerpc/powernv/npu: Do not try invalidating 32bit table when 64bit table is enabled") did just that but in pci-ioda.c while it actually belongs to npu-dma.c. This moves the single TVE handling to npu-dma.c. This does not implement restoring though as it is highly unlikely that we can set the table to PCI PE and cannot to NPU PE and if that fails, we could only set 32bit table to NPU PE and this configuration is not really supported or wanted. Signed-off-by:
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Alexey Kardashevskiy authored
The iommu_table pointer stored in iommu_table_group may get stale by accident, this adds referencing and removes a redundant comment about this. Signed-off-by:
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Alexey Kardashevskiy authored
Registering new IOMMU groups and adding devices to them are separated in code and the latter is dug in the DMA setup code which it does not really belong to. This moved IOMMU groups setup to a separate helper which registers a group and adds devices as before. This does not make a difference as IOMMU groups are not used anyway; the only dependency here is that iommu_add_device() requires a valid pointer to an iommu_table (set by set_iommu_table_base()). To keep the old behaviour, this does not add new IOMMU groups for PEs with no DMA weight and also skips NVLink bridges which do not have pci_controller_ops::setup_bridge (the normal way of adding PEs). Signed-off-by:
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Alexey Kardashevskiy authored
The powernv platform registers IOMMU groups and adds devices to them from the pci_controller_ops::setup_bridge() hook except one case when virtual functions (SRIOV VFs) are added from a bus notifier. The pseries platform registers IOMMU groups from the pci_controller_ops::dma_bus_setup() hook and adds devices from the pci_controller_ops::dma_dev_setup() hook. The very same bus notifier used for powernv does not add devices for pseries though as __of_scan_bus() adds devices first, then it does the bus/dev DMA setup. Both platforms use iommu_add_device() which takes a device and expects it to have a valid IOMMU table struct with an iommu_table_group pointer which in turn points the iommu_group struct (which represents an IOMMU group). Although the helper seems easy to use, it relies on some pre-existing device configuration and associated data structures which it does not really need. This simplifies iommu_add_device() to take the table_group pointer directly. Pseries already has a table_group pointer handy and the bus notified is not used anyway. For powernv, this copies the existing bus notifier, makes it work for powernv only which means an easy way of getting to the table_group pointer. This was tested on VFs but should also support physical PCI hotplug. Since iommu_add_device() receives the table_group pointer directly, pseries does not do TCE cache invalidation (the hypervisor does) nor allow multiple groups per a VFIO container (in other words sharing an IOMMU table between partitionable endpoints), this removes iommu_table_group_link from pseries. Signed-off-by:
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Alexey Kardashevskiy authored
The pci_dma_bus_setup_pSeries and pci_dma_dev_setup_pSeries hooks are registered for the pseries platform which does not have FW_FEATURE_LPAR; these would be pre-powernv platforms which we never supported PCI pass through for anyway so remove it. Signed-off-by:
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Alexey Kardashevskiy authored
We already changed NPU API for GPUs to not to call OPAL and the remaining bit is initializing NPU structures. This searches for POWER9 NVLinks attached to any device on a PHB and initializes an NPU structure if any found. Signed-off-by:
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Alexey Kardashevskiy authored
We might have memory@ nodes with "linux,usable-memory" set to zero (for example, to replicate powernv's behaviour for GPU coherent memory) which means that the memory needs an extra initialization but since it can be used afterwards, the pseries platform will try mapping it for DMA so the DMA window needs to cover those memory regions too; if the window cannot cover new memory regions, the memory onlining fails. This walks through the memory nodes to find the highest RAM address to let a huge DMA window cover that too in case this memory gets onlined later. Signed-off-by:
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Alexey Kardashevskiy authored
When introduced, the NPU context init/destroy helpers called OPAL which enabled/disabled PID (a userspace memory context ID) filtering in an NPU per a GPU; this was a requirement for P9 DD1.0. However newer chip revision added a PID wildcard support so there is no more need to call OPAL every time a new context is initialized. Also, since the PID wildcard support was added, skiboot does not clear wildcard entries in the NPU so these remain in the hardware till the system reboot. This moves LPID and wildcard programming to the PE setup code which executes once during the booting process so NPU2 context init/destroy won't need to do additional configuration. This replaces the check for FW_FEATURE_OPAL with a check for npu!=NULL as this is the way to tell if the NPU support is present and configured. This moves pnv_npu2_init() declaration as pseries should be able to use it. This keeps pnv_npu2_map_lpar() in powernv as pseries is not allowed to call that. This exports pnv_npu2_map_lpar_dev() as following patches will use it from the VFIO driver. While at it, replace redundant list_for_each_entry_safe() with a simpler list_for_each_entry(). Signed-off-by:
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Alexey Kardashevskiy authored
The powernv PCI code stores NPU data in the pnv_phb struct. The latter is referenced by pci_controller::private_data. We are going to have NPU2 support in the pseries platform as well but it does not store any private_data in in the pci_controller struct; and even if it did, it would be a different data structure. This makes npu a pointer and stores it one level higher in the pci_controller struct. Signed-off-by:
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Alexey Kardashevskiy authored
This new memory does not have page structs as it is not plugged to the host so gup() will fail anyway. This adds 2 helpers: - mm_iommu_newdev() to preregister the "memory device" memory so the rest of API can still be used; - mm_iommu_is_devmem() to know if the physical address is one of thise new regions which we must avoid unpinning of. This adds @mm to tce_page_is_contained() and iommu_tce_xchg() to test if the memory is device memory to avoid pfn_to_page(). This adds a check for device memory in mm_iommu_ua_mark_dirty_rm() which does delayed pages dirtying. Signed-off-by:
Paul Mackerras <paulus@ozlabs.org> Signed-off-by:
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Alexey Kardashevskiy authored
Normally mm_iommu_get() should add a reference and mm_iommu_put() should remove it. However historically mm_iommu_find() does the referencing and mm_iommu_get() is doing allocation and referencing. We are going to add another helper to preregister device memory so instead of having mm_iommu_new() (which pre-registers the normal memory and references the region), we need separate helpers for pre-registering and referencing. This renames: - mm_iommu_get to mm_iommu_new; - mm_iommu_find to mm_iommu_get. This changes mm_iommu_get() to reference the region so the name now reflects what it does. This removes the check for exact match from mm_iommu_new() as we want it to fail on existing regions; mm_iommu_get() should be used instead. Signed-off-by:
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Alexey Kardashevskiy authored
The skiboot firmware has a hot reset handler which fences the NVIDIA V100 GPU RAM on Witherspoons and makes accesses no-op instead of throwing HMIs: https://github.com/open-power/skiboot/commit/fca2b2b839a67 Now we are going to pass V100 via VFIO which most certainly involves KVM guests which are often terminated without getting a chance to offline GPU RAM so we end up with a running machine with misconfigured memory. Accessing this memory produces hardware management interrupts (HMI) which bring the host down. To suppress HMIs, this wires up this hot reset hook to vfio_pci_disable() via pci_disable_device() which switches NPU2 to a safe mode and prevents HMIs. Signed-off-by:
Alistair Popple <alistair@popple.id.au> Reviewed-by:
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Christophe Leroy authored
On the 8xx, no-execute is set via PPP bits in the PTE. Therefore a no-exec fault generates DSISR_PROTFAULT error bits, not DSISR_NOEXEC_OR_G. This patch adds DSISR_PROTFAULT in the test mask. Fixes: d3ca5874 ("powerpc/mm: Fix reporting of kernel execute faults") Signed-off-by:
Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by:
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Firoz Khan authored
System call table generation script must be run to gener- ate unistd_32/64.h and syscall_table_32/64/c32/spu.h files. This patch will have changes which will invokes the script. This patch will generate unistd_32/64.h and syscall_table- _32/64/c32/spu.h files by the syscall table generation script invoked by parisc/Makefile and the generated files against the removed files must be identical. The generated uapi header file will be included in uapi/- asm/unistd.h and generated system call table header file will be included by kernel/systbl.S file. Signed-off-by:
Firoz Khan <firoz.khan@linaro.org> Signed-off-by:
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Firoz Khan authored
The system call tables are in different format in all architecture and it will be difficult to manually add or modify the system calls in the respective files. To make it easy by keeping a script and which will generate the uapi header and syscall table file. This change will also help to unify the implementation across all architectures. The system call table generation script is added in syscalls directory which contain the script to generate both uapi header file and system call table files. The syscall.tbl file will be the input for the scripts. syscall.tbl contains the list of available system calls along with system call number and corresponding entry point. Add a new system call in this architecture will be possible by adding new entry in the syscall.tbl file. Adding a new table entry consisting of: - System call number. - ABI. - System call name. - Entry point name. - Compat entry name, if required. syscallhdr.sh and syscalltbl.sh will generate uapi header- unistd_32/64.h and syscall_table_32/64/c32/spu.h files respectively. File syscall_table_32/64/c32/spu.h is incl- uded by syscall.S - the real system call table. Both *.sh files will parse the content syscall.tbl to generate the header and table files. ARM, s390 and x86 architecuture does have similar support. I leverage their implementation to come up with a generic solution. Signed-off-by:
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Firoz Khan authored
PowerPC uses a syscall table with native and compat calls interleaved, which is a slightly simpler way to define two matching tables. As we move to having the tables generated, that advantage is no longer important, but the interleaved table gets in the way of using the same scripts as on the other archit- ectures. Split out a new compat_sys_call_table symbol that contains all the compat calls, and leave the main table for the nat- ive calls, to more closely match the method we use every- where else. Suggested-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
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Firoz Khan authored
Move the macro definition for compat_sys_sigsuspend from asm/systbl.h to the file which it is getting included. One of the patch in this patch series is generating uapi header and syscall table files. In order to come up with a common implimentation across all architecture, we need to do this change. This change will simplify the implementation of system call table generation script and help to come up a common implementation across all architecture. Signed-off-by:
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Firoz Khan authored
NR_syscalls macro holds the number of system call exist in powerpc architecture. We have to change the value of NR_syscalls, if we add or delete a system call. One of the patch in this patch series has a script which will generate a uapi header based on syscall.tbl file. The syscall.tbl file contains the number of system call information. So we have two option to update NR_syscalls value. 1. Update NR_syscalls in asm/unistd.h manually by count- ing the no.of system calls. No need to update NR_sys- calls until we either add a new system call or delete existing system call. 2. We can keep this feature in above mentioned script, that will count the number of syscalls and keep it in a generated file. In this case we don't need to expli- citly update NR_syscalls in asm/unistd.h file. The 2nd option will be the recommended one. For that, I added the __NR_syscalls macro in uapi/asm/unistd.h along with NR_syscalls asm/unistd.h. The macro __NR_syscalls also added for making the name convention same across all architecture. While __NR_syscalls isn't strictly part of the uapi, having it as part of the generated header to simplifies the implementation. We also need to enclose this macro with #ifdef __KERNEL__ to avoid side effects. Signed-off-by:
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Ram Pai authored
Protection key tracking information is not copied over to the mm_struct of the child during fork(). This can cause the child to erroneously allocate keys that were already allocated. Any allocated execute-only key is lost aswell. Add code; called by dup_mmap(), to copy the pkey state from parent to child explicitly. This problem was originally found by Dave Hansen on x86, which turns out to be a problem on powerpc aswell. Fixes: cf43d3b2 ("powerpc: Enable pkey subsystem") Cc: stable@vger.kernel.org # v4.16+ Reviewed-by:
Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by:
Ram Pai <linuxram@us.ibm.com> Signed-off-by:
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Greg Kurz authored
The AFU Descriptor Template in the PCI config space has a Name Space field which is a 24 Byte ASCII character string of descriptive name space for the AFU. The OCXL driver read the string four characters at a time with pci_read_config_dword(). This optimization is valid on a little-endian system since this is PCI, but a big-endian system ends up with each subset of four characters in reverse order. This could be fixed by switching to read characters one by one. Another option is to swap the bytes if we're big-endian. Go for the latter with le32_to_cpu(). Cc: stable@vger.kernel.org # v4.16 Signed-off-by:
Greg Kurz <groug@kaod.org> Acked-by:
Frederic Barrat <fbarrat@linux.ibm.com> Acked-by:
Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by:
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Breno Leitao authored
This is a new test case that creates a signal and starts a suspended transaction inside the signal handler. It returns from the signal handler with the CPU at suspended state, but without setting user context MSR Transaction State (TS) field. The kernel signal handler code should be able to handle this discrepancy instead of crashing. This code could be compiled and used to test 32 and 64-bits signal handlers. Signed-off-by:
Breno Leitao <leitao@debian.org> Signed-off-by:
Gustavo Romero <gromero@linux.vnet.ibm.com> Signed-off-by:
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Breno Leitao authored
There is a TM Bad Thing bug that can be caused when you return from a signal context in a suspended transaction but with ucontext MSR[TS] unset. This forces regs->msr[TS] to be set at syscall entrance (since the CPU state is transactional). It also calls treclaim() to flush the transaction state, which is done based on the live (mfmsr) MSR state. Since user context MSR[TS] is not set, then restore_tm_sigcontexts() is not called, thus, not executing recheckpoint, keeping the CPU state as not transactional. When calling rfid, SRR1 will have MSR[TS] set, but the CPU state is non transactional, causing the TM Bad Thing with the following stack: [ 33.862316] Bad kernel stack pointer 3fffd9dce3e0 at c00000000000c47c cpu 0x8: Vector: 700 (Program Check) at [c00000003ff7fd40] pc: c00000000000c47c: fast_exception_return+0xac/0xb4 lr: 00003fff865f442c sp: 3fffd9dce3e0 msr: 8000000102a03031 current = 0xc00000041f68b700 paca = 0xc00000000fb84800 softe: 0 irq_happened: 0x01 pid = 1721, comm = tm-signal-sigre Linux version 4.9.0-3-powerpc64le (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.30-2+deb9u2 (2017-06-26) WARNING: exception is not recoverable, can't continue The same problem happens on 32-bits signal handler, and the fix is very similar, if tm_recheckpoint() is not executed, then regs->msr[TS] should be zeroed. This patch also fixes a sparse warning related to lack of indentation when CONFIG_PPC_TRANSACTIONAL_MEM is set. Fixes: 2b0a576d ("powerpc: Add new transactional memory state to the signal context") CC: Stable <stable@vger.kernel.org> # 3.10+ Signed-off-by:
Michal Suchánek <msuchanek@suse.de> Signed-off-by:
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Breno Leitao authored
Usually a TM Bad Thing exception is raised due to three different problems. a) touching SPRs in an active transaction; b) using TM instruction with the facility disabled and c) setting a wrong MSR/SRR1 at RFID. The two initial cases are easy to identify by looking at the instructions. The latter case is harder, because the MSR is masked after RFID, so, it is very useful to look at the previous MSR (SRR1) before RFID as also the current and masked MSR. Since MSR is saved at paca just before RFID, this patch prints it if a TM Bad thing happen, helping to understand what is the invalid TM transition that is causing the exception. Signed-off-by:
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Breno Leitao authored
As other exit points, move SRR1 (MSR) into paca->tm_scratch, so, if there is a TM Bad Thing in RFID, it is easy to understand what was the SRR1 value being used. Signed-off-by:
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Breno Leitao authored
On a signal handler return, the user could set a context with MSR[TS] bits set, and these bits would be copied to task regs->msr. At restore_tm_sigcontexts(), after current task regs->msr[TS] bits are set, several __get_user() are called and then a recheckpoint is executed. This is a problem since a page fault (in kernel space) could happen when calling __get_user(). If it happens, the process MSR[TS] bits were already set, but recheckpoint was not executed, and SPRs are still invalid. The page fault can cause the current process to be de-scheduled, with MSR[TS] active and without tm_recheckpoint() being called. More importantly, without TEXASR[FS] bit set also. Since TEXASR might not have the FS bit set, and when the process is scheduled back, it will try to reclaim, which will be aborted because of the CPU is not in the suspended state, and, then, recheckpoint. This recheckpoint will restore thread->texasr into TEXASR SPR, which might be zero, hitting a BUG_ON(). kernel BUG at /build/linux-sf3Co9/linux-4.9.30/arch/powerpc/kernel/tm.S:434! cpu 0xb: Vector: 700 (Program Check) at [c00000041f1576d0] pc: c000000000054550: restore_gprs+0xb0/0x180 lr: 0000000000000000 sp: c00000041f157950 msr: 8000000100021033 current = 0xc00000041f143000 paca = 0xc00000000fb86300 softe: 0 irq_happened: 0x01 pid = 1021, comm = kworker/11:1 kernel BUG at /build/linux-sf3Co9/linux-4.9.30/arch/powerpc/kernel/tm.S:434! Linux version 4.9.0-3-powerpc64le (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.30-2+deb9u2 (2017-06-26) enter ? for help [c00000041f157b30] c00000000001bc3c tm_recheckpoint.part.11+0x6c/0xa0 [c00000041f157b70] c00000000001d184 __switch_to+0x1e4/0x4c0 [c00000041f157bd0] c00000000082eeb8 __schedule+0x2f8/0x990 [c00000041f157cb0] c00000000082f598 schedule+0x48/0xc0 [c00000041f157ce0] c0000000000f0d28 worker_thread+0x148/0x610 [c00000041f157d80] c0000000000f96b0 kthread+0x120/0x140 [c00000041f157e30] c00000000000c0e0 ret_from_kernel_thread+0x5c/0x7c This patch simply delays the MSR[TS] set, so, if there is any page fault in the __get_user() section, it does not have regs->msr[TS] set, since the TM structures are still invalid, thus avoiding doing TM operations for in-kernel exceptions and possible process reschedule. With this patch, the MSR[TS] will only be set just before recheckpointing and setting TEXASR[FS] = 1, thus avoiding an interrupt with TM registers in invalid state. Other than that, if CONFIG_PREEMPT is set, there might be a preemption just after setting MSR[TS] and before tm_recheckpoint(), thus, this block must be atomic from a preemption perspective, thus, calling preempt_disable/enable() on this code. It is not possible to move tm_recheckpoint to happen earlier, because it is required to get the checkpointed registers from userspace, with __get_user(), thus, the only way to avoid this undesired behavior is delaying the MSR[TS] set. The 32-bits signal handler seems to be safe this current issue, but, it might be exposed to the preemption issue, thus, disabling preemption in this chunk of code. Changes from v2: * Run the critical section with preempt_disable. Fixes: 87b4e539 ("powerpc/tm: Fix return of active 64bit signals") Cc: stable@vger.kernel.org (v3.9+) Signed-off-by:
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Mahesh Salgaonkar authored
For fadump to work successfully there should not be any holes in reserved memory ranges where kernel has asked firmware to move the content of old kernel memory in event of crash. Now that fadump uses CMA for reserved area, this memory area is now not protected from hot-remove operations unless it is cma allocated. Hence, fadump service can fail to re-register after the hot-remove operation, if hot-removed memory belongs to fadump reserved region. To avoid this make sure that memory from fadump reserved area is not hot-removable if fadump is registered. However, if user still wants to remove that memory, he can do so by manually stopping fadump service before hot-remove operation. Signed-off-by:
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by:
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Mahesh Salgaonkar authored
fadump fails to register when there are holes in reserved memory area. This can happen if user has hot-removed a memory that falls in the fadump reserved memory area. Throw a meaningful error message to the user in such case. Signed-off-by:
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Mahesh Salgaonkar authored
One of the primary issues with Firmware Assisted Dump (fadump) on Power is that it needs a large amount of memory to be reserved. On large systems with TeraBytes of memory, this reservation can be quite significant. In some cases, fadump fails if the memory reserved is insufficient, or if the reserved memory was DLPAR hot-removed. In the normal case, post reboot, the preserved memory is filtered to extract only relevant areas of interest using the makedumpfile tool. While the tool provides flexibility to determine what needs to be part of the dump and what memory to filter out, all supported distributions default this to "Capture only kernel data and nothing else". We take advantage of this default and the Linux kernel's Contiguous Memory Allocator (CMA) to fundamentally change the memory reservation model for fadump. Instead of setting aside a significant chunk of memory nobody can use, this patch uses CMA instead, to reserve a significant chunk of memory that the kernel is prevented from using (due to MIGRATE_CMA), but applications are free to use it. With this fadump will still be able to capture all of the kernel memory and most of the user space memory except the user pages that were present in CMA region. Essentially, on a P9 LPAR with 2 cores, 8GB RAM and current upstream: [root@zzxx-yy10 ~]# free -m total used free shared buff/cache available Mem: 7557 193 6822 12 541 6725 Swap: 4095 0 4095 With this patch: [root@zzxx-yy10 ~]# free -m total used free shared buff/cache available Mem: 8133 194 7464 12 475 7338 Swap: 4095 0 4095 Changes made here are completely transparent to how fadump has traditionally worked. Thanks to Aneesh Kumar and Anshuman Khandual for helping us understand CMA and its usage. TODO: - Handle case where CMA reservation spans nodes. Signed-off-by:Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Signed-off-by:
Hari Bathini <hbathini@linux.ibm.com> Signed-off-by:
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Mahesh Salgaonkar authored
opal_power_control_init() depends on opal message notifier to be initialized, which is done in opal_init()->opal_message_init(). But both these initialization are called through machine initcalls and it all depends on in which order they being called. So far these are called in correct order (may be we got lucky) and never saw any issue. But it is clearer to control initialization order explicitly by moving opal_power_control_init() into opal_init(). Signed-off-by:
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Markus Elfring authored
The script "checkpatch.pl" pointed information out like the following. WARNING: void function return statements are not generally useful Thus remove such a statement in the affected functions. Signed-off-by:
Markus Elfring <elfring@users.sourceforge.net> Signed-off-by:
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Markus Elfring authored
Omit an extra message for a memory allocation failure in these functions. This issue was detected by using the Coccinelle software. Signed-off-by:
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Markus Elfring authored
A single character (line break) should be put into a sequence. Thus use the corresponding function "seq_putc". This issue was detected by using the Coccinelle software. Signed-off-by:
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