- 15 5月, 2008 1 次提交
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由 Heiko Carstens 提交于
Both smp_call_function() and __smp_call_function_map() access cpu_online_map. Both functions run with preemption disabled which protects for cpus going offline. However new cpus can be added and therefore the cpu_online_map can change unexpectedly. So use the call_lock to protect against changes to the cpu_online_map in start_secondary() and all smp_call_* functions. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 30 4月, 2008 2 次提交
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由 Heiko Carstens 提交于
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
On some smp sysfs store attributes get_online_cpus() may block on cpu_hotplug.lock, but we hold already smp_cpu_state_mutex. Since the locking order on cpu hotplug via arch_update_cpu_topology is inverse this might lead to deadlocks. So make sure locking order is always the same. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 17 4月, 2008 4 次提交
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由 Heiko Carstens 提交于
Most noteable part of this commit is the new local header file entry.h which contains all the function declarations of functions that get only called from asm code or are arch internal. That way we can avoid extern declarations in C files. This is more or less the same that was done for sparc64. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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由 Heiko Carstens 提交于
Remove the program check generating monitor calls and use function calls instead. Theres is no real advantage in using monitor calls, but they do make debugging harder, because of all the program checks it generates. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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由 Heiko Carstens 提交于
If vertical cpu polarization is active then the hypervisor will dispatch certain cpus for a longer time than other cpus for maximum performance. For example if a guest would have three virtual cpus, each of them with a share of 33 percent, then in case of vertical cpu polarization all of the processing time would be combined to a single cpu which would run all the time, while the other two cpus would get nearly no cpu time. There are three different types of vertical cpus: high, medium and low. Low cpus hardly get any real cpu time, while high cpus get a full real cpu. Medium cpus get something in between. In order to switch between the two possible modes (default is horizontal) a 0 for horizontal polarization or a 1 for vertical polarization must be written to the dispatching sysfs attribute: /sys/devices/system/cpu/dispatching The polarization of each single cpu can be figured out by the polarization sysfs attribute of each cpu: /sys/devices/system/cpu/cpuX/polarization horizontal, vertical:high, vertical:medium, vertical:low or unknown. When switching polarization the polarization attribute may contain the value unknown until the configuration change is done and the kernel has figured out the new polarization of each cpu. Note that running a system with different types of vertical cpus may result in significant performance regressions. If possible only one type of vertical cpus should be used. All other cpus should be offlined. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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由 Heiko Carstens 提交于
Add s390 backend so we can give the scheduler some hints about the cpu topology. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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- 05 3月, 2008 1 次提交
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由 Heiko Carstens 提交于
Compile smp.o with -Wno-nonnull so gcc stops warning about memcpy being used with a null parameter. Also remove the workaround code and use a char * cast instead of a void * cast to do computations. Cc: Bastian Blank <bastian@waldi.eu.org> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 19 2月, 2008 1 次提交
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由 Heiko Carstens 提交于
Just copy the first 512 read-only bytes of the current cpu lowcore if a new cpu gets onlined. The rest is zeroed out and must be explicitly initialized. Current code just copies the entire lowcore and initializes the needed fields. This should reveal bugs in future enhancements quite early. Also when the lowcore of the first cpu is replaced this is now done atomically (no interrupts, no machine checks). Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 05 2月, 2008 2 次提交
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由 Heiko Carstens 提交于
Fix couple of section mismatches. And since we touch the code anyway change the IPL code to use C99 initializers. Cc: Michael Holzheu <holzheu@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
Make sure func isn't called on the local cpu just like on all other architectures that implement this function. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 26 1月, 2008 6 次提交
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由 Martin Schwidefsky 提交于
Git commit 86ef5c9a forgot a few lock_cpu_hotplug/unlock_cpu_hotplug pairs in arch/s390/kernel/smp.c Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Carsten Otte 提交于
This patch adds the s390 variant for smp_call_function_mask(). The implementation is pretty straight forward using the wrapper __smp_call_function_map() which already takes a cpumask_t argument. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
No need to preallocate the per cpu lowcores and stacks. Savings are 28-32k per offline cpu. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Michael Holzheu 提交于
In case of a kernel panic it is currently possible to specify that a dump should be created, the system should be rebooted or stopped. Virtual sysfs files under the directory /sys/firmware/ are used for that configuration. In addition to that, there are kernel parameters 'vmhalt', 'vmpoff' and 'vmpanic', which can be used to specify z/VM commands, which are automatically executed in case of halt, power off or a kernel panic. This patch combines both functionalities and allows to specify the z/VM CP commands also via sysfs attributes. In addition to that, it enhances the existing handling of shutdown triggers (e.g. halt or panic) and associated shutdown actions (e.g. dump or reipl) and makes it more flexible. Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
It caused only a lot of confusion. From now on cpu hotplug of up to NR_CPUS will work by default. If somebody wants to limit that then the possible_cpus parameter can be used. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
Add a new interface so that cpus can be put into standby state and configured state. Only offline cpus can be put into standby state or configured state. For that the new percpu sysfs attribute "configure" must be used. To put a cpu in standby state a "0" must be written to the attribute. In order to switch it into configured state a "1" must be written to the attribute. Only cpus in configured state can be brought online. In addition this patch introduces a static mapping of physical to logical cpus. As a result only the sysfs directories of present cpus will be created. To scan for new cpus the new sysfs attribute "rescan" must be used. Writing to /sys/devices/system/cpu/rescan will trigger a rescan of cpus and will create directories for new cpus. On IPL only configured cpus will be used. And on reboot/shutdown all cpus will remain in their current state (configured/standby). Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 20 11月, 2007 1 次提交
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由 Heiko Carstens 提交于
Don't perform a sigp store-status-at-address on smp_send_stop(). It will overwrite the lowcores of other cpus and destroys valueable debug informations. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 05 11月, 2007 1 次提交
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由 Heiko Carstens 提交于
Seems that people prefer to have the unit encoded in the attribute name. Also makes parsing easier. Now we have: # cat /sys/devices/system/cpu/cpu0/idle_time_us 131473592 instead of # cat /sys/devices/system/cpu/cpu0/idle_time 131473592 us Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 22 10月, 2007 2 次提交
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由 Martin Schwidefsky 提交于
The current tlb flushing code for page table entries violates the s390 architecture in a small detail. The relevant section from the principles of operation (SA22-7832-02 page 3-47): "A valid table entry must not be changed while it is attached to any CPU and may be used for translation by that CPU except to (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page-table entry, or (3) make a change by means of a COMPARE AND SWAP AND PURGE instruction that purges the TLB." That means if one thread of a multithreaded applciation uses a vma while another thread does an unmap on it, the page table entries of that vma needs to get removed with IPTE, IDTE or CSP. In some strange and rare situations a cpu could check-stop (die) because a entry has been pushed out of the TLB that is still needed to complete a (milli-coded) instruction. I've never seen it happen with the current code on any of the supported machines, so right now this is a theoretical problem. But I want to fix it nevertheless, to avoid headaches in the futures. To get this implemented correctly without changing common code the primitives ptep_get_and_clear, ptep_get_and_clear_full and ptep_set_wrprotect need to use the IPTE instruction to invalidate the pte before the new pte value gets stored. If IPTE is always used for the three primitives three important operations will have a performace hit: fork, mprotect and exit_mmap. Time for some workarounds: * 1: ptep_get_and_clear_full is used in unmap_vmas to remove page tables entries in a batched tlb gather operation. If the mmu_gather context passed to unmap_vmas has been started with full_mm_flush==1 or if only one cpu is online or if the only user of a mm_struct is the current process then the fullmm indication in the mmu_gather context is set to one. All TLBs for mm_struct are flushed by the tlb_gather_mmu call. No new TLBs can be created while the unmap is in progress. In this case ptep_get_and_clear_full clears the ptes with a simple store. * 2: ptep_get_and_clear is used in change_protection to clear the ptes from the page tables before they are reentered with the new access flags. At the end of the update flush_tlb_range clears the remaining TLBs. In general the ptep_get_and_clear has to issue IPTE for each pte and flush_tlb_range is a nop. But if there is only one user of the mm_struct then ptep_get_and_clear uses simple stores to do the update and flush_tlb_range will flush the TLBs. * 3: Similar to 2, ptep_set_wrprotect is used in copy_page_range for a fork to make all ptes of a cow mapping read-only. At the end of of copy_page_range dup_mmap will flush the TLBs with a call to flush_tlb_mm. Check for mm->mm_users and if there is only one user avoid using IPTE in ptep_set_wrprotect and let flush_tlb_mm clear the TLBs. Overall for single threaded programs the tlb flush code now performs better, for multi threaded programs it is slightly worse. In particular exit_mmap() now does a single IDTE for the mm and then just frees every page cache reference and every page table page directly without a delay over the mmu_gather structure. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
Add two new sysfs entries per cpu: idle_count and idle_time. idle_count contains the number of times a cpu went into idle state. idle_time contains the time a cpu spent in idle state in microseconds. This can be used e.g. by powertop to tell how often idle state is entered and left. # cat /sys/devices/system/cpu/cpu0/idle_count 504 # cat /sys/devices/system/cpu/cpu0/idle_time 469734037 us Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 30 7月, 2007 1 次提交
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由 Alexey Dobriyan 提交于
Remove fs.h from mm.h. For this, 1) Uninline vma_wants_writenotify(). It's pretty huge anyway. 2) Add back fs.h or less bloated headers (err.h) to files that need it. As result, on x86_64 allyesconfig, fs.h dependencies cut down from 3929 files rebuilt down to 3444 (-12.3%). Cross-compile tested without regressions on my two usual configs and (sigh): alpha arm-mx1ads mips-bigsur powerpc-ebony alpha-allnoconfig arm-neponset mips-capcella powerpc-g5 alpha-defconfig arm-netwinder mips-cobalt powerpc-holly alpha-up arm-netx mips-db1000 powerpc-iseries arm arm-ns9xxx mips-db1100 powerpc-linkstation arm-assabet arm-omap_h2_1610 mips-db1200 powerpc-lite5200 arm-at91rm9200dk arm-onearm mips-db1500 powerpc-maple arm-at91rm9200ek arm-picotux200 mips-db1550 powerpc-mpc7448_hpc2 arm-at91sam9260ek arm-pleb mips-ddb5477 powerpc-mpc8272_ads arm-at91sam9261ek arm-pnx4008 mips-decstation powerpc-mpc8313_rdb arm-at91sam9263ek arm-pxa255-idp mips-e55 powerpc-mpc832x_mds arm-at91sam9rlek arm-realview mips-emma2rh powerpc-mpc832x_rdb arm-ateb9200 arm-realview-smp mips-excite powerpc-mpc834x_itx arm-badge4 arm-rpc mips-fulong powerpc-mpc834x_itxgp arm-carmeva arm-s3c2410 mips-ip22 powerpc-mpc834x_mds arm-cerfcube arm-shannon mips-ip27 powerpc-mpc836x_mds arm-clps7500 arm-shark mips-ip32 powerpc-mpc8540_ads arm-collie arm-simpad mips-jazz powerpc-mpc8544_ds arm-corgi arm-spitz mips-jmr3927 powerpc-mpc8560_ads arm-csb337 arm-trizeps4 mips-malta powerpc-mpc8568mds arm-csb637 arm-versatile mips-mipssim powerpc-mpc85xx_cds arm-ebsa110 i386 mips-mpc30x powerpc-mpc8641_hpcn arm-edb7211 i386-allnoconfig mips-msp71xx powerpc-mpc866_ads arm-em_x270 i386-defconfig mips-ocelot powerpc-mpc885_ads arm-ep93xx i386-up mips-pb1100 powerpc-pasemi arm-footbridge ia64 mips-pb1500 powerpc-pmac32 arm-fortunet ia64-allnoconfig mips-pb1550 powerpc-ppc64 arm-h3600 ia64-bigsur mips-pnx8550-jbs powerpc-prpmc2800 arm-h7201 ia64-defconfig mips-pnx8550-stb810 powerpc-ps3 arm-h7202 ia64-gensparse mips-qemu powerpc-pseries arm-hackkit ia64-sim mips-rbhma4200 powerpc-up arm-integrator ia64-sn2 mips-rbhma4500 s390 arm-iop13xx ia64-tiger mips-rm200 s390-allnoconfig arm-iop32x ia64-up mips-sb1250-swarm s390-defconfig arm-iop33x ia64-zx1 mips-sead s390-up arm-ixp2000 m68k mips-tb0219 sparc arm-ixp23xx m68k-amiga mips-tb0226 sparc-allnoconfig arm-ixp4xx m68k-apollo mips-tb0287 sparc-defconfig arm-jornada720 m68k-atari mips-workpad sparc-up arm-kafa m68k-bvme6000 mips-wrppmc sparc64 arm-kb9202 m68k-hp300 mips-yosemite sparc64-allnoconfig arm-ks8695 m68k-mac parisc sparc64-defconfig arm-lart m68k-mvme147 parisc-allnoconfig sparc64-up arm-lpd270 m68k-mvme16x parisc-defconfig um-x86_64 arm-lpd7a400 m68k-q40 parisc-up x86_64 arm-lpd7a404 m68k-sun3 powerpc x86_64-allnoconfig arm-lubbock m68k-sun3x powerpc-cell x86_64-defconfig arm-lusl7200 mips powerpc-celleb x86_64-up arm-mainstone mips-atlas powerpc-chrp32 Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 7月, 2007 2 次提交
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由 Heiko Carstens 提交于
There is no need to disable bottom halves when holding call_lock. Also this could imply that it is legal to call smp_call_function* from bh context, which it is not. Also test if func will be executed locally before disabling and aterwards enabling interrupts again. It's not necessary to disable and enable interrupts each time __smp_call_function_map gets called. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
smp_call_function_single now has the same semantics as s390's smp_call_function_on. Therefore convert to the *single variant and get rid of some architecture specific code. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 10 7月, 2007 1 次提交
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由 Heiko Carstens 提交于
Merge smp_count_cpus() and smp_get_save_areas() so we save a loop over all potentially present cpus. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 31 5月, 2007 1 次提交
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由 Heiko Carstens 提交于
Use the __cpuinit instead of __devinit section annotations for code that deals with cpu hotplug. In addition add some more annotations on functions that have been left out so far. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 10 5月, 2007 1 次提交
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由 Rafael J. Wysocki 提交于
Since nonboot CPUs are now disabled after tasks and devices have been frozen and the CPU hotplug infrastructure is used for this purpose, we need special CPU hotplug notifications that will help the CPU-hotplug-aware subsystems distinguish normal CPU hotplug events from CPU hotplug events related to a system-wide suspend or resume operation in progress. This patch introduces such notifications and causes them to be used during suspend and resume transitions. It also changes all of the CPU-hotplug-aware subsystems to take these notifications into consideration (for now they are handled in the same way as the corresponding "normal" ones). [oleg@tv-sign.ru: cleanups] Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 5月, 2007 1 次提交
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由 Randy Dunlap 提交于
Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 4月, 2007 3 次提交
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由 Heiko Carstens 提交于
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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由 Heiko Carstens 提交于
Generate uevents for all cpus if cpu capability changes. This can happen e.g. because the cpus are overheating. The cpu capability can be read via /sys/devices/system/cpu/cpuN/capability. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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由 Michael Holzheu 提交于
s390 machines provide hardware support for creating Linux dumps on SCSI disks. For creating a dump a special purpose dump Linux is used. The first 32 MB of memory are saved by the hardware before the dump Linux is booted. Via an SCLP interface, the saved memory can be accessed from Linux. This patch exports memory and registers of the crashed Linux to userspace via a debugfs file. For more information refer to Documentation/s390/zfcpdump.txt, which is included in this patch. Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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- 06 3月, 2007 1 次提交
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由 Heiko Carstens 提交于
Avoid sprinkling a _lot_ of preempt_disable/preempt_enable pairs. This would be necessary for e.g. the iucv driver. Also this way we are more consistent with other architectures which disable preemption at least for smp_call_function. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 21 2月, 2007 2 次提交
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由 Michael Holzheu 提交于
Setup.h has been misused for ipl related stuff in the past. We now move everything, which has to do with ipl and reipl to a new header file named "ipl.h". Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Jan Glauber 提交于
Introduce __smp_call_function_map which calls a function on all cpus given with a cpumask_t. Use it to implement smp_call_function and smp_call_function_on. Replace smp_ext_bitcall_others with smp_ext_bitcall and a for_each_cpu_mask loop. Use a cpumask_t instead of an atomic_t for cpu counting and print a warning if preempt is on in __smp_call_function_map(). Signed-off-by: NJan Glauber <jan.glauber@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 12 2月, 2007 1 次提交
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由 Heiko Carstens 提交于
smp_call_function and smp_call_function_on share the same lock and smp_call_function_on disables softirq's so it can be called from softirq context as well. Hence smp_call_function muss disable softirqs as well to avoid deadlocks. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 06 2月, 2007 4 次提交
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由 Heiko Carstens 提交于
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Martin Schwidefsky 提交于
This patch adds support for clock synchronization to an external time reference (ETR). The external time reference sends an oscillator signal and a synchronization signal every 2^20 microseconds to keep the TOD clocks of all connected servers in sync. For availability two ETR units can be connected to a machine. If the clock deviates for more than the sync-check tolerance all cpus get a machine check that indicates that the clock is out of sync. For the lovely details how to get the clock back in sync see the code below. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Gerald Schaefer 提交于
This provides a noexec protection on s390 hardware. Our hardware does not have any bits left in the pte for a hw noexec bit, so this is a different approach using shadow page tables and a special addressing mode that allows separate address spaces for code and data. As a special feature of our "secondary-space" addressing mode, separate page tables can be specified for the translation of data addresses (storage operands) and instruction addresses. The shadow page table is used for the instruction addresses and the standard page table for the data addresses. The shadow page table is linked to the standard page table by a pointer in page->lru.next of the struct page corresponding to the page that contains the standard page table (since page->private is not really private with the pte_lock and the page table pages are not in the LRU list). Depending on the software bits of a pte, it is either inserted into both page tables or just into the standard (data) page table. Pages of a vma that does not have the VM_EXEC bit set get mapped only in the data address space. Any try to execute code on such a page will cause a page translation exception. The standard reaction to this is a SIGSEGV with two exceptions: the two system call opcodes 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn) are allowed. They are stored by the kernel to the signal stack frame. Unfortunately, the signal return mechanism cannot be modified to use an SA_RESTORER because the exception unwinding code depends on the system call opcode stored behind the signal stack frame. This feature requires that user space is executed in secondary-space mode and the kernel in home-space mode, which means that the addressing modes need to be switched and that the noexec protection only works for user space. After switching the addressing modes, we cannot use the mvcp/mvcs instructions anymore to copy between kernel and user space. A new mvcos instruction has been added to the z9 EC/BC hardware which allows to copy between arbitrary address spaces, but on older hardware the page tables need to be walked manually. Signed-off-by: NGerald Schaefer <geraldsc@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 09 1月, 2007 1 次提交
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由 Heiko Carstens 提交于
72486f1f inverts the logic if an 'online' attribute in /sys/devices/system/cpu/cpuX should appear. So we end up with no hotpluggable cpus at all... Set the hotpluggable value to one to make sure the online attribute appears again. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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