- 22 Jul, 2015 4 commits
-
-
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>
-
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:
-
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:
-
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:
-
- 20 Jul, 2015 1 commit
-
-
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:
-
- 17 Jul, 2015 1 commit
-
-
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:
Dominik Dingel <dingel@linux.vnet.ibm.com> Acked-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
- 13 Jul, 2015 2 commits
-
-
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:
-
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:
-
- 07 Jul, 2015 1 commit
-
-
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:
-
- 29 Jun, 2015 1 commit
-
-
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:
-
- 26 Jun, 2015 2 commits
-
-
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:
-
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:
-
- 25 Jun, 2015 5 commits
-
-
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:
-
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:
-
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:
-
- 18 Jun, 2015 1 commit
-
-
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:
Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by:
-
- 08 Jun, 2015 1 commit
-
-
Bjorn Helgaas authored
We already include <asm/pci.h> from <linux/pci.h>, so just include <linux/pci.h> directly. Signed-off-by:Bjorn Helgaas <bhelgaas@google.com> CC: linuxppc-dev@lists.ozlabs.org CC: linux-s390@vger.kernel.org
-
- 28 May, 2015 1 commit
-
-
Luis R. Rodriguez authored
Most code already uses consts for the struct kernel_param_ops, sweep the kernel for the last offending stragglers. Other than include/linux/moduleparam.h and kernel/params.c all other changes were generated with the following Coccinelle SmPL patch. Merge conflicts between trees can be handled with Coccinelle. In the future git could get Coccinelle merge support to deal with patch --> fail --> grammar --> Coccinelle --> new patch conflicts automatically for us on patches where the grammar is available and the patch is of high confidence. Consider this a feature request. Test compiled on x86_64 against: * allnoconfig * allmodconfig * allyesconfig @ const_found @ identifier ops; @@ const struct kernel_param_ops ops = { }; @ const_not_found depends on !const_found @ identifier ops; @@ -struct kernel_param_ops ops = { +const struct kernel_param_ops ops = { }; Generated-by: Coccinelle SmPL Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Junio C Hamano <gitster@pobox.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: cocci@systeme.lip6.fr Cc: linux-kernel@vger.kernel.org Signed-off-by:Luis R. Rodriguez <mcgrof@suse.com> Signed-off-by:
Rusty Russell <rusty@rustcorp.com.au>
-
- 22 May, 2015 1 commit
-
-
Xunlei Pang authored
As part of addressing the "y2038 problem" for in-kernel uses, this patch converts read_boot_clock() to read_boot_clock64() and read_persistent_clock() to read_persistent_clock64() using timespec64. Rename some instances of 'timespec' to 'timespec64' in time.c and related references Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Signed-off-by:
Xunlei Pang <pang.xunlei@linaro.org> [jstultz: Fixed minor style and grammer tweaks pointed out by Ingo] Signed-off-by:
John Stultz <john.stultz@linaro.org>
-
- 13 May, 2015 3 commits
-
-
David Hildenbrand authored
As all relevant sclp data is now directly accessible, let's move the logic of these two functions to the single caller. Acked-by:
David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by:
-
David Hildenbrand authored
Let's unify basic access to sclp fields by storing the data in an external struct in asm/sclp.h. The values can now directly be accessed by other components, so there is no need for most accessor functions and external variables anymore. The mtid, mtid_max and facility part will be cleaned up separately. Acked-by:
-
David Hildenbrand authored
We need to rename sclp -> sclp_max to prepare for using the global variable "sclp" for sclp access later in this function. Acked-by:
-
- 08 May, 2015 1 commit
-
-
Christian Borntraeger authored
exit_sie_sync is used to kick CPUs out of SIE and prevent reentering at any point in time. This is used to reload the prefix pages and to set the IBS stuff in a way that guarantees that after this function returns we are no longer in SIE. All current users trigger KVM requests. The request must be set before we block the CPUs to avoid races. Let's make this implicit by adding the request into a new function kvm_s390_sync_requests that replaces exit_sie_sync and split out s390_vcpu_block and s390_vcpu_unblock, that can be used to keep CPUs out of SIE independent of requests. Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by:
Cornelia Huck <cornelia.huck@de.ibm.com>
-
- 13 Apr, 2015 3 commits
-
-
Heiko Carstens authored
This is the s390 version of 875ebe94 ("powerpc/smp: Wait until secondaries are active & online"). The race described in length within the commit message is also possible on s390 and every other architecture. So fix this race on s390 as well. Signed-off-by:
-
Heiko Carstens authored
Sebastian reported a crash caused by a jump label mismatch after resume. This happens because we do not save the kernel text section during suspend and therefore also do not restore it during resume, but use the kernel image that restores the old system. This means that after a suspend/resume cycle we lost all modifications done to the kernel text section. The reason for this is the pfn_is_nosave() function, which incorrectly returns that read-only pages don't need to be saved. This is incorrect since we mark the kernel text section read-only. We still need to make sure to not save and restore pages contained within NSS and DCSS segment. To fix this add an extra case for the kernel text section and only save those pages if they are not contained within an NSS segment. Fixes the following crash (and the above bugs as well): Jump label code mismatch at netif_receive_skb_internal+0x28/0xd0 Found: c0 04 00 00 00 00 Expected: c0 f4 00 00 00 11 New: c0 04 00 00 00 00 Kernel panic - not syncing: Corrupted kernel text CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.19.0-01975-gb1b096e70f23 #4 Call Trace: [<0000000000113972>] show_stack+0x72/0xf0 [<000000000081f15e>] dump_stack+0x6e/0x90 [<000000000081c4e8>] panic+0x108/0x2b0 [<000000000081be64>] jump_label_bug.isra.2+0x104/0x108 [<0000000000112176>] __jump_label_transform+0x9e/0xd0 [<00000000001121e6>] __sm_arch_jump_label_transform+0x3e/0x50 [<00000000001d1136>] multi_cpu_stop+0x12e/0x170 [<00000000001d1472>] cpu_stopper_thread+0xb2/0x168 [<000000000015d2ac>] smpboot_thread_fn+0x134/0x1b0 [<0000000000158baa>] kthread+0x10a/0x110 [<0000000000824a86>] kernel_thread_starter+0x6/0xc Reported-and-tested-by:
-
Heiko Carstens authored
Git commit d97d929f ("s390: move cacheinfo sysfs to generic cacheinfo infrastructure") removed the general-instructions-extension availability check before the ecag instruction is executed. Without this check this may lead to crashes on machines without this facility. Therefore add the check again where needed. Signed-off-by:
-
- 12 Apr, 2015 1 commit
-
-
Richard Weinberger authored
As execution domain support is gone we can remove signal translation from the signal code and remove exec_domain from thread_info. Signed-off-by:Richard Weinberger <richard@nod.at>
-
- 27 Mar, 2015 1 commit
-
-
Peter Zijlstra authored
In preparation of adding another tkr field, rename this one to tkr_mono. Also rename tk_read_base::base_mono to tk_read_base::base, since the structure is not specific to CLOCK_MONOTONIC and the mono name got added to the tk_read_base instance. Lots of trivial churn. Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
Ingo Molnar <mingo@kernel.org>
-
- 25 Mar, 2015 10 commits
-
-
Heiko Carstens authored
Add a BUILD_BUG_ON() to enforce that irqclass_sub_desc contains the required number of defined interrupt descriptions and won't be filled up with zeros. Signed-off-by:
-
Heiko Carstens authored
Rename two more files which I forgot. Also remove the "asm" from the swsusp_asm64.S file, since the ".S" suffix already makes it obvious that this file contains assembler code. Signed-off-by:
-
Sebastian Ott authored
ipl.c uses 3 different macros to create a sysfs show function for ipl attributes. Define IPL_ATTR_SHOW_FN which is used by all macros. Reviewed-by:
-
Sebastian Ott authored
Use macros wherever applicable and create a shutdown_action attribute group to simplify the code. Reviewed-by:
-
Sebastian Ott authored
Use macros wherever applicable and put bin_attributes inside attribute_groups to simplify/remove some code. Reviewed-by:
-
Heiko Carstens authored
Remove __user address space annotation for sim_stor_event() calls since it generates false positive warnings from sparse. Signed-off-by:
-
Heiko Carstens authored
As reported by sparse these can and should be static. Signed-off-by:
-
Heiko Carstens authored
Remove the s390 architecture implementation of probe_kernel_write() and instead use a new function s390_kernel_write() to modify kernel text and data everywhere. The s390 implementation of probe_kernel_write() was potentially broken since it modified memory in a read-modify-write fashion, which read four bytes, modified the requested bytes within those four bytes and wrote the result back. If two cpus would modify the same four byte area at different locations within that area, this could lead to corruption. Right now the only places which called probe_kernel_write() did run within stop_machine_run. Therefore the scenario can't happen right now, however that might change at any time. To fix this rename probe_kernel_write() to s390_kernel_write() which can have special semantics, like only call it while running within stop_machine(). Signed-off-by:
-
Heiko Carstens authored
In case of a translation exception the page tables are corrupted. If the exception handler then calls die() which again calls show_regs() -> show_code() -> copy_from_user(), the kernel may access the same memory location again and generates yet another translation exception. Which in turn will lead to a deadlock on the die_lock spinlock, which the kernel tries to grab recursively. Given that the page tables are corrupted anyway, if we see such an exception, let's simply panic. Signed-off-by:
-
Heiko Carstens authored
Remove the 31 bit syscalls from the syscall table. This is a separate patch just in case I screwed something up so it can be easily reverted. However the conversion was done with a script, so everything should be ok. Signed-off-by:
-
