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2015-07-22s390/cio: Implement proper Link Incident Record handlingPeter Oberparleiter1-42/+123
A hardware problem on a FICON link is reported by the Channel Subsystem to the operating system via a Link Incident Record (LIR). In response, the operating system should issue a message that enables hardware service personnel to identify and repair the failing component. Current Linux LIR handling is broken because LIR data is incorrectly interpreted and no log message is generated. This patch fixes Linux LIR handling by implementing a new log message for LIRs indicating a degraded or non-operational link. Also LIRs are no longer used to deactivate channel paths because the available data does not reliably allow to determine the affected channel path. Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/cio: Fix commaPeter Oberparleiter1-1/+1
After dutifully acting as statement separator for 6 long years, this comma has finally grown into a full semicolon. Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/sclp: Change SCLP console default buffer-full behaviorPeter Oberparleiter1-3/+3
Dropping kernel messages during a console-buffer-full condition is preferable to halting the system until console messages are delivered, especially for production systems. Update default for sclp_console_drop kernel parameter accordingly. Signed-off-by: Peter Oberparleiter <peter.oberparleiter@linux.vnet.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/pci: inline get_zdevSebastian Ott4-21/+20
Inline get_zdev to save ~200 bytes of kernel text for CONFIG_PCI=y. Also rename the function to to_zpci to make clear that we don't do reference counting here. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/nmi: use the normal asynchronous stack for machine checksMartin Schwidefsky1-16/+9
If a machine checks is received while the CPU is in the kernel, only the s390_do_machine_check function will be called. The call to s390_handle_mcck is postponed until the CPU returns to user space. Because of this it is safe to use the asynchronous stack for machine checks even if the CPU is already handling an interrupt. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/kernel: squeeze a few more cycles out of the system call handlerMartin Schwidefsky1-41/+34
Reorder the instructions of UPDATE_VTIME to improve superscalar execution, remove duplicate checks for problem-state from the asynchronous interrupt handlers, and move the check for problem-state from the synchronous exit path to the program check path as it is only needed for program checks inside the kernel. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/kvm: integrate HANDLE_SIE_INTERCEPT into cleanup_criticalMartin Schwidefsky1-118/+123
Currently there are two mechanisms to deal with cleanup work due to interrupts. The HANDLE_SIE_INTERCEPT macro is used to undo the changes required to enter SIE in sie64a. If the SIE instruction causes a program check, or an asynchronous interrupt is received the HANDLE_SIE_INTERCEPT code forwards the program execution to sie_exit. All the other critical sections in entry.S are handled by the code in cleanup_critical that is called by the SWITCH_ASYNC macro. Move the sie64a function to the beginning of the critical section and add the code from HANDLE_SIE_INTERCEPT to cleanup_critical. Add a special case for the sie64a cleanup to the program check handler. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/kvm: fix interrupt race with HANDLE_SIE_INTERCEPTMartin Schwidefsky1-10/+4
The HANDLE_SIE_INTERCEPT macro is used in the interrupt handlers and the program check handler to undo a few changes done by sie64a. Among them are guest vs host LPP, the gmap ASCE vs kernel ASCE and the bit that indicates that SIE is currently running on the CPU. There is a race of a voluntary SIE exit vs asynchronous interrupts. If the CPU completed the SIE instruction and the TM instruction of the LPP macro at the time it receives an interrupt, the interrupt handler will run while the LPP, the ASCE and the SIE bit are still set up for guest execution. This might result in wrong sampling data, but it will not cause data corruption or lockups. The critical section in sie64a needs to be enlarged to include all instructions that undo the changes required for guest execution. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/crypto: add cpu feature modaliases for crypto modulesHendrik Brueckner7-8/+14
Use the module_cpu_feature_match() module init function to add an module alias based on required CPU features. The modules are automatically loaded on hardware that supports the required CPU features. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/module: enable generic CPU feature modalias using s390 ELF hwcapsHendrik Brueckner4-1/+40
Add support for the generic CPU feature modalias implementation that wires up optional CPU features to udev-based module autoprobing. The <asm/cpufeature.h> file provides definitions to map CPU features to s390 ELF hardware capabilities. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22cpufeature: correctly annotate the module init functionHendrik Brueckner1-3/+4
A section mismatch warning is reported if an __init annotated function is specified for module_cpu_feature_match(). Change the module_cpu_feature_match() function and annotate the generated cpu_feature_match_* function as __init. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-22s390/kernel: lazy restore fpu registersHendrik Brueckner15-203/+482
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>