- 22 Jul, 2015 7 commits
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Hendrik Brueckner authored
Improve the save and restore behavior of FPU register contents to use the vector extension within the kernel. The kernel does not use floating-point or vector registers and, therefore, saving and restoring the FPU register contents are performed for handling signals or switching processes only. To prepare for using vector instructions and vector registers within the kernel, enhance the save behavior and implement a lazy restore at return to user space from a system call or interrupt. To implement the lazy restore, the save_fpu_regs() sets a CPU information flag, CIF_FPU, to indicate that the FPU registers must be restored. Saving and setting CIF_FPU is performed in an atomic fashion to be interrupt-safe. When the kernel wants to use the vector extension or wants to change the FPU register state for a task during signal handling, the save_fpu_regs() must be called first. The CIF_FPU flag is also set at process switch. At return to user space, the FPU state is restored. In particular, the FPU state includes the floating-point or vector register contents, as well as, vector-enablement and floating-point control. The FPU state restore and clearing CIF_FPU is also performed in an atomic fashion. For KVM, the restore of the FPU register state is performed when restoring the general-purpose guest registers before the SIE instructions is started. Because the path towards the SIE instruction is interruptible, the CIF_FPU flag must be checked again right before going into SIE. If set, the guest registers must be reloaded again by re-entering the outer SIE loop. This is the same behavior as if the SIE critical section is interrupted. Signed-off-by:
Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com>
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Hendrik Brueckner authored
Older binutils versions do not include support for the vector instruction formats. Add assembler macros for vector instruction mnemonics to easily encode and generate vector instructions. Signed-off-by:
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Hendrik Brueckner authored
Make the floating-point save area dynamically allocated and uses a flag to distinguish whether a task uses floating-point or vector registers. Signed-off-by:
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Hendrik Brueckner authored
Introduce a new structure to manage FP and VX registers. Refactor the save and restore of floating point and vector registers with a set of helper functions in fpu-internal.h. Signed-off-by:
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Hendrik Brueckner authored
The kvm_arch_vcpu_load() does not validate whether the floating-point control (FPC) is valid. Further, the return code of the restore is not checked too. If the FPC is invalid, the restore fails and the host FPC value might remain. The correct behavior would be to clear the FPC if it is not valid. Hence, validate the FPC value and, optionally, reset the value before restoring it. Reviewed-by:
David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by:
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Hendrik Brueckner authored
Use the test_fp_ctl() to test the floating-point control word for validity and use restore_fp_ctl() to set it in load_sigregs. Signed-off-by:
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Hendrik Brueckner authored
Move the EX_TABLE macro definitions from the processor.h to the linkage.h header file. It helps to reduce circular header file dependencies. Signed-off-by:
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- 20 Jul, 2015 1 commit
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Martin Schwidefsky authored
git commit 0c8c0f03 "x86/fpu, sched: Dynamically allocate 'struct fpu'" moved the thread_struct to the end of the task_struct. This causes some of the offsets used in entry.S to overflow their instruction operand field. To fix this use aghi to create a dedicated pointer for the thread_struct. Signed-off-by:
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- 17 Jul, 2015 4 commits
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Laurent Dufour authored
Commit 2ae416b1 ("mm: new mm hook framework") introduced an empty header file (mm-arch-hooks.h) for every architecture, even those which doesn't need to define mm hooks. As suggested by Geert Uytterhoeven, this could be cleaned through the use of a generic header file included via each per architecture asm/include/Kbuild file. The PowerPC architecture is not impacted here since this architecture has to defined the arch_remap MM hook. Signed-off-by:
Laurent Dufour <ldufour@linux.vnet.ibm.com> Suggested-by:
Geert Uytterhoeven <geert@linux-m68k.org> Acked-by:
Vineet Gupta <vgupta@synopsys.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Dominik Dingel authored
On s390 we only can enable hugepages if the underlying hardware/hypervisor also does support this. Common code now would assume this to be signaled by setting HPAGE_SHIFT to 0. But on s390, where we only support one hugepage size, there is a link between HPAGE_SHIFT and pageblock_order. So instead of setting HPAGE_SHIFT to 0, we will implement the check for the hardware capability. Signed-off-by:
Dominik Dingel <dingel@linux.vnet.ibm.com> Acked-by:
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Dominik Dingel authored
Heiko noticed that the current check for hugepage support on s390 is a little bit too harsh as systems which do not support will crash. The reason is that pageblock_order can now get negative when we set HPAGE_SHIFT to 0. To avoid all this and to avoid opening another can of worms with enabling HUGETLB_PAGE_SIZE_VARIABLE I think it would be best to simply allow architectures to define their own hugepages_supported(). Revert bea41197 ("s390/mm: make hugepages_supported a boot time decision") in preparation. Signed-off-by:
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Dominik Dingel authored
Heiko noticed that the current check for hugepage support on s390 is a little bit too harsh as systems which do not support will crash. The reason is that pageblock_order can now get negative when we set HPAGE_SHIFT to 0. To avoid all this and to avoid opening another can of worms with enabling HUGETLB_PAGE_SIZE_VARIABLE I think it would be best to simply allow architectures to define their own hugepages_supported(). This patch (of 4): revert commit cf54e2fc ("s390/mm: change HPAGE_SHIFT type to int") in preparation. Signed-off-by:
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- 13 Jul, 2015 2 commits
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Heiko Carstens authored
If a machine check happens, the machine has the vector facility installed and the extended save area exists, the cpu will save vector register contents into the extended save area. This is regardless of control register 0 contents, which enables and disables the vector facility during runtime. On each machine check we should validate the vector registers. The current code however tries to validate the registers only if the running task is using vector registers in user space. However even the current code is broken and causes vector register corruption on machine checks, if user space uses them: the prefix area contains a pointer (absolute address) to the machine check extended save area. In order to save some space the save area was put into an unused area of the second prefix page. When validating vector register contents the code uses the absolute address of the extended save area, which is wrong. Due to prefixing the vector instructions will then access contents using absolute addresses instead of real addresses, where the machine stored the contents. If the above would work there is still the problem that register validition would only happen if user space uses vector registers. If kernel space uses them also, this may also lead to vector register content corruption: if the kernel makes use of vector instructions, but the current running user space context does not, the machine check handler will validate floating point registers instead of vector registers. Given the fact that writing to a floating point register may change the upper halve of the corresponding vector register, we also experience vector register corruption in this case. Fix all of these issues, and always validate vector registers on each machine check, if the machine has the vector facility installed and the extended save area is defined. Cc: <stable@vger.kernel.org> # 4.1+ Signed-off-by:
Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by:
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Heiko Carstens authored
The sfpc inline assembly within execve_tail() may incorrectly set bits 28-31 of the sfpc instruction to a value which is not zero. These bits however are currently unused and therefore should be zero so we won't get surprised if these bits will be used in the future. Therefore remove the second operand from the inline assembly. Cc: <stable@vger.kernel.org> Signed-off-by:
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- 07 Jul, 2015 1 commit
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Martin Schwidefsky authored
If the kernel is compiled with gcc 5.1 and the XZ compression option the decompress_kernel function calls _sclp_print_early in 64-bit mode while the content of the upper register half of %r6 is non-zero. This causes a specification exception on the servc instruction in _sclp_servc. The _sclp_print_early function saves and restores the upper registers halves but it fails to clear them for the 31-bit code of the mini sclp driver. Cc: <stable@vger.kernel.org> Signed-off-by:
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- 01 Jul, 2015 2 commits
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Eric W. Biederman authored
This allows for better documentation in the code and it allows for a simpler and fully correct version of fs_fully_visible to be written. The mount points converted and their filesystems are: /sys/hypervisor/s390/ s390_hypfs /sys/kernel/config/ configfs /sys/kernel/debug/ debugfs /sys/firmware/efi/efivars/ efivarfs /sys/fs/fuse/connections/ fusectl /sys/fs/pstore/ pstore /sys/kernel/tracing/ tracefs /sys/fs/cgroup/ cgroup /sys/kernel/security/ securityfs /sys/fs/selinux/ selinuxfs /sys/fs/smackfs/ smackfs Cc: stable@vger.kernel.org Acked-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
"Eric W. Biederman" <ebiederm@xmission.com>
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Sebastian Ott authored
Fix these errors when compiling with CONFIG_OPROFILE=y and CONFIG_PERF_EVENTS=n: arch/s390/oprofile/init.c: In function ‘oprofile_hwsampler_start’: arch/s390/oprofile/init.c:93:2: error: implicit declaration of function 'perf_reserve_sampling' [-Werror=implicit-function-declaration] retval = perf_reserve_sampling(); ^ arch/s390/oprofile/init.c:99:3: error: implicit declaration of function 'perf_release_sampling' [-Werror=implicit-function-declaration] perf_release_sampling(); ^ Signed-off-by:
Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by:
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- 29 Jun, 2015 1 commit
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Heiko Carstens authored
Fix this compile error: arch/s390/kernel/setup.c:875:2: error: implicit declaration of function 'smp_save_dump_cpus' Signed-off-by:
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- 26 Jun, 2015 5 commits
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Josh Triplett authored
clone has some of the quirkiest syscall handling in the kernel, with a pile of special cases, historical curiosities, and architecture-specific calling conventions. In particular, clone with CLONE_SETTLS accepts a parameter "tls" that the C entry point completely ignores and some assembly entry points overwrite; instead, the low-level arch-specific code pulls the tls parameter out of the arch-specific register captured as part of pt_regs on entry to the kernel. That's a massive hack, and it makes the arch-specific code only work when called via the specific existing syscall entry points; because of this hack, any new clone-like system call would have to accept an identical tls argument in exactly the same arch-specific position, rather than providing a unified system call entry point across architectures. The first patch allows architectures to handle the tls argument via normal C parameter passing, if they opt in by selecting HAVE_COPY_THREAD_TLS. The second patch makes 32-bit and 64-bit x86 opt into this. These two patches came out of the clone4 series, which isn't ready for this merge window, but these first two cleanup patches were entirely uncontroversial and have acks. I'd like to go ahead and submit these two so that other architectures can begin building on top of this and opting into HAVE_COPY_THREAD_TLS. However, I'm also happy to wait and send these through the next merge window (along with v3 of clone4) if anyone would prefer that. This patch (of 2): clone with CLONE_SETTLS accepts an argument to set the thread-local storage area for the new thread. sys_clone declares an int argument tls_val in the appropriate point in the argument list (based on the various CLONE_BACKWARDS variants), but doesn't actually use or pass along that argument. Instead, sys_clone calls do_fork, which calls copy_process, which calls the arch-specific copy_thread, and copy_thread pulls the corresponding syscall argument out of the pt_regs captured at kernel entry (knowing what argument of clone that architecture passes tls in). Apart from being awful and inscrutable, that also only works because only one code path into copy_thread can pass the CLONE_SETTLS flag, and that code path comes from sys_clone with its architecture-specific argument-passing order. This prevents introducing a new version of the clone system call without propagating the same architecture-specific position of the tls argument. However, there's no reason to pull the argument out of pt_regs when sys_clone could just pass it down via C function call arguments. Introduce a new CONFIG_HAVE_COPY_THREAD_TLS for architectures to opt into, and a new copy_thread_tls that accepts the tls parameter as an additional unsigned long (syscall-argument-sized) argument. Change sys_clone's tls argument to an unsigned long (which does not change the ABI), and pass that down to copy_thread_tls. Architectures that don't opt into copy_thread_tls will continue to ignore the C argument to sys_clone in favor of the pt_regs captured at kernel entry, and thus will be unable to introduce new versions of the clone syscall. Patch co-authored by Josh Triplett and Thiago Macieira. Signed-off-by:
Josh Triplett <josh@joshtriplett.org> Acked-by:
Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thiago Macieira <thiago.macieira@intel.com> Signed-off-by:
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Dominik Dingel authored
With making HPAGE_SHIFT an unsigned integer we also accidentally changed pageblock_order. In order to avoid compiler warnings we make HPAGE_SHFIT an int again. Signed-off-by:
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Dominik Dingel authored
We already do the check in pmd_large, so we can just forward the call. Signed-off-by:
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Dominik Dingel authored
We now support only hugepages on hardware with EDAT1 support. So we remove the prepare/release_hugepage hooks and simplify set_huge_pte_at and huge_ptep_get. Signed-off-by:
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Dominik Dingel authored
There is a potential bug with KVM and hugetlbfs if the hardware does not support hugepages (EDAT1). We fix this by making EDAT1 a hard requirement for hugepages and therefore removing and simplifying code. As s390, with the sw-emulated hugepages, was the only user of arch_prepare/release_hugepage I also removed theses calls from common and other architecture code. This patch (of 5): By dropping support for hugepages on machines which do not have the hardware feature EDAT1, we fix a potential s390 KVM bug. The bug would happen if a guest is backed by hugetlbfs (not supported currently), but does not get pagetables with PGSTE. This would lead to random memory overwrites. Signed-off-by:
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- 25 Jun, 2015 12 commits
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Michael Holzheu authored
It turned out that SIGP set-multi-threading can only be done once. Therefore switching to a different MT level after switching to sclp.mtid_prev in the dump case fails. As a symptom specifying the "nosmt" parameter currently fails for the kdump kernel and the kernel starts with multi-threading enabled. So fix this and issue diag 308 subcode 1 call after collecting the CPU states for the dump. Also enhance the diag308_reset() function to be usable also with enabled lowcore protection and prefix register != 0. After the reset it is possible to switch the MT level again. We have to do the reset very early in order not to kill the already initialized console. Therefore instead of kmalloc() the corresponding memblock functions have to be used. To avoid copying the sclp cpu code into sclp_early, we now use the simple sigp loop method for CPU detection. Signed-off-by:
Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by:
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Heiko Carstens authored
Signed-off-by:
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Martin Schwidefsky authored
The SCLP interface to query, configure and deconfigure CPUs actually operates on cores. For a machine without the multi-threading faciltiy a CPU and a core are equivalent but starting with System z13 a core can have multiple hardware threads, also referred to as logical CPUs. To avoid confusion replace the word 'cpu' with 'core' in the SCLP interface. Also replace MAX_CPU_ADDRESS with SCLP_MAX_CORES. The core-id is an 8-bit field, the maximum thread id is in the range 0-31. The theoretical limit for the CPU address is therefore 8191. Signed-off-by: -
Martin Schwidefsky authored
On a (theoretical) system where the read-cpu-info SCLP command does not work but SMT is enabled, the sigp detection loop may not find all configured cores. The maximum CPU address needs to be shifted with smp_cpu_mt_shift. Signed-off-by: -
Michael Holzheu authored
The REGSET_VX_LOW ELF notes should contain the lower 64 bit halfes of the first sixteen 128 bit vector registers. Unfortunately currently we copy the upper halfes. Fix this and correctly copy the lower halfes. Fixes: a62bc073 ("s390/kdump: add support for vector extension") Cc: stable@vger.kernel.org # 3.18+ Signed-off-by:
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Michael Holzheu authored
Currently all backward jumps crash for JITed s390x eBPF programs with an illegal instruction program check and kernel panic. Because for negative values the opcode of the jump instruction is overriden by the negative branch offset an illegal instruction is generated by the JIT: 000003ff802da378: c01100000002 lgfi %r1,2 000003ff802da37e: fffffff52065 unknown <-- illegal instruction 000003ff802da384: b904002e lgr %r2,%r14 So fix this and mask the offset in order not to damage the opcode. Cc: stable@vger.kernel.org # 4.0+ Signed-off-by:
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Tony Luck authored
Some high end Intel Xeon systems report uncorrectable memory errors as a recoverable machine check. Linux has included code for some time to process these and just signal the affected processes (or even recover completely if the error was in a read only page that can be replaced by reading from disk). But we have no recovery path for errors encountered during kernel code execution. Except for some very specific cases were are unlikely to ever be able to recover. Enter memory mirroring. Actually 3rd generation of memory mirroing. Gen1: All memory is mirrored Pro: No s/w enabling - h/w just gets good data from other side of the mirror Con: Halves effective memory capacity available to OS/applications Gen2: Partial memory mirror - just mirror memory begind some memory controllers Pro: Keep more of the capacity Con: Nightmare to enable. Have to choose between allocating from mirrored memory for safety vs. NUMA local memory for performance Gen3: Address range partial memory mirror - some mirror on each memory controller Pro: Can tune the amount of mirror and keep NUMA performance Con: I have to write memory management code to implement The current plan is just to use mirrored memory for kernel allocations. This has been broken into two phases: 1) This patch series - find the mirrored memory, use it for boot time allocations 2) Wade into mm/page_alloc.c and define a ZONE_MIRROR to pick up the unused mirrored memory from mm/memblock.c and only give it out to select kernel allocations (this is still being scoped because page_alloc.c is scary). This patch (of 3): Add extra "flags" to memblock to allow selection of memory based on attribute. No functional changes Signed-off-by:Tony Luck <tony.luck@intel.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Xiexiuqi <xiexiuqi@huawei.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Signed-off-by:
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Aneesh Kumar K.V authored
We have confusing functions to clear pmd, pmd_clear_* and pmd_clear. Add _huge_ to pmdp_clear functions so that we are clear that they operate on hugepage pte. We don't bother about other functions like pmdp_set_wrprotect, pmdp_clear_flush_young, because they operate on PTE bits and hence indicate they are operating on hugepage ptes Signed-off-by:
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by:
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Aneesh Kumar K.V authored
Also move the pmd_trans_huge check to generic code. Signed-off-by:
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Zhang Zhen authored
Currently we have many duplicates in definitions of hugetlb_prefault_arch_hook. In all architectures this function is empty. Signed-off-by:
Zhang Zhen <zhenzhang.zhang@huawei.com> Acked-by:
David Rientjes <rientjes@google.com> Signed-off-by:
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Laurent Dufour authored
CRIU is recreating the process memory layout by remapping the checkpointee memory area on top of the current process (criu). This includes remapping the vDSO to the place it has at checkpoint time. However some architectures like powerpc are keeping a reference to the vDSO base address to build the signal return stack frame by calling the vDSO sigreturn service. So once the vDSO has been moved, this reference is no more valid and the signal frame built later are not usable. This patch serie is introducing a new mm hook framework, and a new arch_remap hook which is called when mremap is done and the mm lock still hold. The next patch is adding the vDSO remap and unmap tracking to the powerpc architecture. This patch (of 3): This patch introduces a new set of header file to manage mm hooks: - per architecture empty header file (arch/x/include/asm/mm-arch-hooks.h) - a generic header (include/linux/mm-arch-hooks.h) The architecture which need to overwrite a hook as to redefine it in its header file, while architecture which doesn't need have nothing to do. The default hooks are defined in the generic header and are used in the case the architecture is not defining it. In a next step, mm hooks defined in include/asm-generic/mm_hooks.h should be moved here. Signed-off-by:
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Zhang Zhen authored
Currently we have many duplicates in definitions of huge_pmd_unshare. In all architectures this function just returns 0 when CONFIG_ARCH_WANT_HUGE_PMD_SHARE is N. This patch puts the default implementation in mm/hugetlb.c and lets these architectures use the common code. Signed-off-by:
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- 23 Jun, 2015 2 commits
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Al Viro authored
Signed-off-by:Al Viro <viro@zeniv.linux.org.uk>
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Jens Freimann authored
commit 6d3da241 ("KVM: s390: deliver floating interrupts in order of priority") introduced a regression for the reset handling. We don't clear the bitmap of pending floating interrupts and interrupt parameters. This could result in stale interrupts even after a reset. Let's fix this by clearing the pending bitmap and the parameters for service and machine check interrupts. Cc: stable@vger.kernel.org # 4.1 Signed-off-by:
Jens Freimann <jfrei@linux.vnet.ibm.com> Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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- 18 Jun, 2015 2 commits
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Sebastian Ott authored
Hypervisors may deliver event 0x301 not only for standby but also for reserved devices. Just handle event 0x301 regardless of the device's state. Reviewed-by:
Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by:
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Sebastian Ott authored
Addresses from the usable space in [_ehead, _stext] lead to false positives in DMA_API_DEBUG code (which will complain when an address is in [_text, _etext]). Avoid these warnings by not using that memory in case of CONFIG_DMA_API_DEBUG=y. Signed-off-by:
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- 15 Jun, 2015 1 commit
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Geert Uytterhoeven authored
Signed-off-by:
Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by:
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