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* powerpc/time: add API for KVM to re-arm the host timer/decrementerNicholas Piggin2021-11-241-12/+4
| | | | | | | | | | | | | | | | | | Rather than have KVM look up the host timer and fiddle with the irq-work internal details, have the powerpc/time.c code provide a function for KVM to re-arm the Linux timer code when exiting a guest. This is implementation has an improvement over existing code of marking a decrementer interrupt as soft-pending if a timer has expired, rather than setting DEC to a -ve value, which tended to cause host timers to take two interrupts (first hdec to exit the guest, then the immediate dec). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-8-npiggin@gmail.com
* KVM: PPC: Book3S HV P9: Use large decrementer for HDECNicholas Piggin2021-11-241-0/+2
| | | | | | | | | | | | On processors that don't suppress the HDEC exceptions when LPCR[HDICE]=0, this could help reduce needless guest exits due to leftover exceptions on entering the guest. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-6-npiggin@gmail.com
* KVM: PPC: Book3S HV P9: Use host timer accounting to avoid decrementer readNicholas Piggin2021-11-241-0/+5
| | | | | | | | | | | There is no need to save away the host DEC value, as it is derived from the host timer subsystem which maintains the next timer time, so it can be restored from there. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-5-npiggin@gmail.com
* KVM: PPC: Book3S HV P9: Reduce irq_work vs guest decrementer racesNicholas Piggin2021-06-101-0/+12
| | | | | | | | | | | | | | irq_work's use of the DEC SPR is racy with guest<->host switch and guest entry which flips the DEC interrupt to guest, which could lose a host work interrupt. This patch closes one race, and attempts to comment another class of races. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-11-npiggin@gmail.com
* powerpc/time: move timer_broadcast_interrupt prototype to asm/time.hNicholas Piggin2021-02-081-0/+2
| | | | | | | | | Interrupt handler prototypes are going to be rearranged in a future patch, so tidy this out of the way first. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-21-npiggin@gmail.com
* powerpc/time: Remove ifdef in get_vtb()Christophe Leroy2020-12-031-2/+1
| | | | | | | | | SPRN_VTB and CPU_FTR_ARCH_207S are always defined, no need of an ifdef. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/a0fc81cd85121407726bcf480fc9a0d8e7617fce.1601549933.git.christophe.leroy@csgroup.eu
* powerpc/time: Move timebase functions into new asm/vdso/timebase.hChristophe Leroy2020-12-031-29/+1
| | | | | | | | | In order to easily use get_tb() from C VDSO, move timebase functions into a new header named asm/vdso/timebase.h Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201126131006.2431205-3-mpe@ellerman.id.au
* powerpc/time: Make get_tb() common to PPC32 and PPC64Christophe Leroy2020-10-081-7/+3
| | | | | | | | | | mftbu() is always defined now, so the #ifdef can be removed and replaced by an IS_ENABLED(CONFIG_PPC64) inside the PPC32 version of get_tb(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/47e49717d2643169ffcbe5d507f184cf49f0fe95.1601556145.git.christophe.leroy@csgroup.eu
* powerpc/time: Make get_tbl() common to PPC32 and PPC64Christophe Leroy2020-10-081-7/+0
| | | | | | | | | | | | | On PPC64, get_tbl() is defined as an alias of get_tb() which return the result of mftb(). That exactly the same as what the PPC32 version does. We don't need two versions. Remove the PPC64 definition of get_tbl() and use the PPC32 version for both. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/a8eaabb87d69534e533ebac805163e08146e05bd.1601556145.git.christophe.leroy@csgroup.eu
* powerpc/time: Remove get_tbu()Christophe Leroy2020-10-081-5/+0
| | | | | | | | | | get_tbu() is redundant with mftbu() and is not used anymore. Remove it. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1746e2d11ea90c3f45877e1fcc6c79ce96cf6b98.1601556145.git.christophe.leroy@csgroup.eu
* powerpc/time: Avoid using get_tbl() and get_tbu() internallyChristophe Leroy2020-10-081-4/+4
| | | | | | | | | | | | | | get_tbl() is confusing as it returns the content of TBL register on PPC32 but the concatenation of TBL and TBU on PPC64. Use mftb() instead. Do the same with get_tbu() for consistency allthough it's name is less confusing. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/41573406a4eab98838decaa91649086fef1e6119.1601556145.git.christophe.leroy@csgroup.eu
* powerpc/time: Rename mftbl() to mftb()Christophe Leroy2020-10-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | On PPC64, we have mftb(). On PPC32, we have mftbl() and an #define mftb() mftbl(). mftb() and mftbl() are equivalent, their purpose is to read the content of SPRN_TRBL, as returned by 'mftb' simplified instruction. binutils seems to define 'mftbl' instruction as an equivalent of 'mftb'. However in both 32 bits and 64 bits documentation, only 'mftb' is defined, and when performing a disassembly with objdump, the displayed instruction is 'mftb' No need to have two ways to do the same thing with different names, rename mftbl() to have only mftb(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/94dc68d3d9ef9eb549796d4b938b6ba0305a049b.1601556145.git.christophe.leroy@csgroup.eu
* powerpc/time: Remove ifdef in get_dec() and set_dec()Christophe Leroy2020-10-081-13/+10
| | | | | | | | | | | Move SPRN_PIT definition in reg.h. This allows to remove ifdef in get_dec() and set_dec() and makes them more readable. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/3c9a6eb0fc040868ac59be66f338d08fd017668d.1601549945.git.christophe.leroy@csgroup.eu
* powerpc: Remove get_tb_or_rtc()Christophe Leroy2020-10-081-5/+0
| | | | | | | | | | 601 is gone, get_tb_or_rtc() is equivalent to get_tb(). Replace the former by the later. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/3e8a13ee83418630c753c30cb722ae682d5b2d39.1601362098.git.christophe.leroy@csgroup.eu
* powerpc: Remove __USE_RTC()Christophe Leroy2020-10-081-27/+1
| | | | | | | | | | | | Now that PowerPC 601 is gone, __USE_RTC() is never true. Remove it. That also leads to removing get_rtc() and get_rtcl() Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/4757e1ed21fe1968c761ae081d1f3d790a9673f8.1601362098.git.christophe.leroy@csgroup.eu
* powerpc: Remove support for PowerPC 601Christophe Leroy2020-10-081-1/+1
| | | | | | | | | | | | | | | | | | PowerPC 601 has been retired. Remove all associated specific code. CPU_FTRS_PPC601 has CPU_FTR_COHERENT_ICACHE and CPU_FTR_COMMON. CPU_FTR_COMMON is already present via other CPU_FTRS. None of the remaining CPU selects CPU_FTR_COHERENT_ICACHE. So CPU_FTRS_PPC601 can be removed from the possible features, hence can be removed completely. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/60b725d55e21beec3335175c20b77903ff98284f.1601362098.git.christophe.leroy@csgroup.eu
* powerpc: Drop old comment about CONFIG_POWERMichael Ellerman2020-07-291-1/+0
| | | | | | | | | | | | | | | There's a comment in time.h referring to CONFIG_POWER, which doesn't exist. That confuses scripts/checkkconfigsymbols.py. Presumably the comment was referring to a CONFIG_POWER vs CONFIG_PPC, in which case for CONFIG_POWER we would #define __USE_RTC to 1. But instead we have CONFIG_PPC_BOOK3S_601, and these days we have IS_ENABLED(). So the comment is no longer relevant, drop it. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200724131728.1643966-9-mpe@ellerman.id.au
* powerpc/40x: Remove support for IBM 403GCXChristophe Leroy2020-05-281-12/+0
| | | | | | | | | | | | CONFIG_403GCX is not user selectable and is not selected by any platform. Remove it. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/635f8f5ce9d1f761b3bd8dc3e8ddad500cea26c4.1590079968.git.christophe.leroy@csgroup.eu
* powerpc/64/sycall: Implement syscall entry/exit logic in CNicholas Piggin2020-04-011-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | System call entry and particularly exit code is beyond the limit of what is reasonable to implement in asm. This conversion moves all conditional branches out of the asm code, except for the case that all GPRs should be restored at exit. Null syscall test is about 5% faster after this patch, because the exit work is handled under local_irq_disable, and the hard mask and pending interrupt replay is handled after that, which avoids games with MSR. mpe: Includes subsequent fixes from Nick: This fixes 4 issues caught by TM selftests. First was a tm-syscall bug that hit due to tabort_syscall being called after interrupts were reconciled (in a subsequent patch), which led to interrupts being enabled before tabort_syscall was called. Rather than going through an un-reconciling interrupts for the return, I just go back to putting the test early in asm, the C-ification of that wasn't a big win anyway. Second is the syscall return _TIF_USER_WORK_MASK check would go into an infinite loop if _TIF_RESTORE_TM became set. The asm code uses _TIF_USER_WORK_MASK to brach to slowpath which includes restore_tm_state. Third is system call return was not calling restore_tm_state, I missed this completely (alhtough it's in the return from interrupt C conversion because when the asm syscall code encountered problems it would branch to the interrupt return code. Fourth is MSR_VEC missing from restore_math, which was caught by tm-unavailable selftest taking an unexpected facility unavailable interrupt when testing VSX unavailble exception with MSR.FP=1 MSR.VEC=1. Fourth case also has a fixup in a subsequent patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200225173541.1549955-26-npiggin@gmail.com
* powerpc/64s/exception: Avoid touching the stack in hdecrementerNicholas Piggin2020-04-011-1/+0
| | | | | | | | | | | | | | | | | | The hdec interrupt handler is reported to sometimes fire in Linux if KVM leaves it pending after a guest exists. This is harmless, so there is a no-op handler for it. The interrupt handler currently uses the regular kernel stack. Change this to avoid touching the stack entirely. This should be the last place where the regular Linux stack can be accessed with asynchronous interrupts (including PMI) soft-masked. It might be possible to take advantage of this invariant, e.g., to context switch the kernel stack SLB entry without clearing MSR[EE]. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200225173541.1549955-17-npiggin@gmail.com
* powerpc/32s: drop CPU_FTR_USE_RTC featureChristophe Leroy2019-08-281-5/+1
| | | | | | | | | | CPU_FTR_USE_RTC feature only applies to powerpc601. Drop this feature and replace it with tests on CONFIG_PPC_BOOK3S_601. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/170411e2360861f4a95c21faad43519a08bc4040.1566834712.git.christophe.leroy@c-s.fr
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner2019-05-301-5/+1
| | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* powerpc/hmi: Fix kernel hang when TB is in error state.Mahesh Salgaonkar2019-05-021-0/+2
| | | | | | | | | | | | | On TOD/TB errors timebase register stops/freezes until HMI error recovery gets TOD/TB back into running state. On successful recovery, TB starts running again and udelay() that relies on TB value continues to function properly. But in case when HMI fails to recover from TOD/TB errors, the TB register stay freezed. With TB not running the __delay() function keeps looping and never return. If __delay() is called while in panic path then system hangs and never reboots after panic. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc: change CONFIG_6xx to CONFIG_PPC_BOOK3S_32Christophe Leroy2018-11-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Today we have: config PPC_BOOK3S_32 bool "512x/52xx/6xx/7xx/74xx/82xx/83xx/86xx" [depends on PPC32 within a choice] config PPC_BOOK3S def_bool y depends on PPC_BOOK3S_32 || PPC_BOOK3S_64 config 6xx def_bool y depends on PPC32 && PPC_BOOK3S 6xx is therefore redundant with PPC_BOOK3S_32. In order to make the code clearer, lets use preferably PPC_BOOK3S_32. This will allow to remove CONFIG_6xx in a later patch. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc: remove unused to_tm() helperArnd Bergmann2018-06-031-2/+0
| | | | | | | | | | to_tm() is now completely unused, the only reference being in the _dump_time() helper that is also unused. This removes both, leaving the rest of the powerpc RTC code y2038 safe to as far as the hardware supports. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc: generic clockevents broadcast receiver call tick_receive_broadcastNicholas Piggin2018-06-031-1/+0
| | | | | | | | | | | | | | | | | | | The broadcast tick recipient can call tick_receive_broadcast rather than re-running the full timer interrupt. It does not have to check for the next event time, because the sender already determined the timer has expired. It does not have to test irq_work_pending, because that's a direct decrementer interrupt and does not go through the clock events subsystem. And it does not have to read PURR because that was removed with the previous patch. This results in no code size change, but both the decrementer and broadcast path lengths are reduced. Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/pseries: lparcfg calculate PURR on demandNicholas Piggin2018-06-031-8/+0
| | | | | | | | | | | | | | | | | | For SPLPAR, lparcfg provides a sum of PURR registers for all CPUs. Currently this is done by reading PURR in context switch and timer interrupt, and storing that into a per-CPU variable. These are summed to provide the value. This does not work with all timer schemes (e.g., NO_HZ_FULL), and it is sub-optimal for performance because it reads the PURR register on every context switch, although that's been difficult to distinguish from noise in the contxt_switch microbenchmark. This patch implements the sum by calling a function on each CPU, to read and add PURR values of each CPU. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* Merge branch 'topic/ppc-kvm' into nextMichael Ellerman2018-03-231-1/+1
|\ | | | | | | | | This brings in two series from Paul, one of which touches KVM code and may need to be merged into the kvm-ppc tree to resolve conflicts.
| * powerpc: Use feature bit for RTC presence rather than timebase presencePaul Mackerras2018-03-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | All PowerPC CPUs other than the original PPC601 have a timebase register rather than the "real-time clock" (RTC) register that the PPC601 (and the original POWER and POWER2 CPUs) had. Currently we have a CPU feature bit to indicate the presence of the timebase, but it makes more sense to use a bit to indicate the unusual situation rather than the common situation. This therefore defines a CPU_FTR_USE_RTC bit in place of the CPU_FTR_USE_TB bit, and arranges for it to be set on PPC601 systems. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* | powerpc: Add missing prototype for time_init()Mathieu Malaterre2018-03-131-0/+1
| | | | | | | | | | | | | | | | | | | | The function time_init did not have a prototype defined in the time.h header. Fix the following warning (treated as error in W=1): arch/powerpc/kernel/time.c:1068:13: error: no previous prototype for ‘time_init’ Signed-off-by: Mathieu Malaterre <malat@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* | powerpc: Add missing prototype for hdec_interruptMathieu Malaterre2018-03-131-0/+1
|/ | | | | | | | | | | In commit dabe859ec636 ("powerpc: Give hypervisor decrementer interrupts their own handler") an empty body function was added, but no prototype was declared. Fix warning (treated as error in W=1): arch/powerpc/kernel/time.c:629:6: error: no previous prototype for ‘hdec_interrupt’ Signed-off-by: Mathieu Malaterre <malat@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc: Move cpu_has_feature() to a separate fileKevin Hao2016-08-011-0/+1
| | | | | | | | | | | | | | | | | We plan to use jump label for cpu_has_feature(). In order to implement this we need to include the linux/jump_label.h in asm/cputable.h. Unfortunately if we do that it leads to an include loop. The root of the problem seems to be that reg.h needs cputable.h (for CPU_FTRs), and then cputable.h via jump_label.h eventually pulls in hw_irq.h which needs reg.h (for MSR_EE). So move cpu_has_feature() to a separate file on its own. Signed-off-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> [mpe: Rename to cpu_has_feature.h and flesh out change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc: Remove mfvtb()Kevin Hao2016-08-011-1/+1
| | | | | | | | | | | | This function is only used by get_vtb(). They are almost the same except the reading from the real register. Move the mfspr() to get_vtb() and kill the function mfvtb(). With this, we can eliminate the use of cpu_has_feature() in very core header file like reg.h. This is a preparation for the use of jump label for cpu_has_feature(). Signed-off-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/timer: Large Decrementer supportOliver O'Halloran2016-07-051-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Power ISAv3 adds a large decrementer (LD) mode which increases the size of the decrementer register. The size of the enlarged decrementer register is between 32 and 64 bits with the exact size being dependent on the implementation. When in LD mode, reads are sign extended to 64 bits and a decrementer exception is raised when the high bit is set (i.e the value goes below zero). Writes however are truncated to the physical register width so some care needs to be taken to ensure that the high bit is not set when reloading the decrementer. This patch adds support for using the LD inside the host kernel on processors that support it. When LD mode is supported firmware will supply the ibm,dec-bits property for CPU nodes to allow the kernel to determine the maximum decrementer value. Enabling LD mode is a hypervisor privileged operation so the kernel can only enable it manually when running in hypervisor mode. Guests that support LD mode can request it using the "ibm,client-architecture-support" firmware call (not implemented in this patch) or some other platform specific method. If this property is not supplied then the traditional decrementer width of 32 bit is assumed and LD mode will not be enabled. This patch was based on initial work by Jack Miller. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Balbir Singh <bsingharora@gmail.com> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/8xx: remove special handling of CPU6 errata in set_dec()Christophe Leroy2016-03-121-5/+1
| | | | | | | | CPU6 ERRATA is now handled directly in mtspr(), so we can use the standard set_dec() fonction in all cases. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Scott Wood <oss@buserror.net>
* powerpc: Remove broken GregorianDay()Daniel Axtens2015-12-161-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GregorianDay() is supposed to calculate the day of the week (tm->tm_wday) for a given day/month/year. In that calcuation it indexed into an array called MonthOffset using tm->tm_mon-1. However tm_mon is zero-based, not one-based, so this is off-by-one. It also means that every January, GregoiranDay() will access element -1 of the MonthOffset array. It also doesn't appear to be a correct algorithm either: see in contrast kernel/time/timeconv.c's time_to_tm function. It's been broken forever, which suggests no-one in userland uses this. It looks like no-one in the kernel uses tm->tm_wday either (see e.g. drivers/rtc/rtc-ds1305.c:319). tm->tm_wday is conventionally set to -1 when not available in hardware so we can simply set it to -1 and drop the function. (There are over a dozen other drivers in drivers/rtc that do this.) Found using UBSAN. Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrew Morton <akpm@linux-foundation.org> # as an example of what UBSan finds. Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com> Cc: rtc-linux@googlegroups.com Signed-off-by: Daniel Axtens <dja@axtens.net> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* KVM: PPC: Book3S HV: Accumulate timing information for real-mode codePaul Mackerras2015-04-211-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
* KVM: PPC: BOOK3S: PR: Emulate virtual timebase registerAneesh Kumar K.V2014-07-281-0/+9
| | | | | | | | | | virtual time base register is a per VM, per cpu register that needs to be saved and restored on vm exit and entry. Writing to VTB is not allowed in the privileged mode. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> [agraf: fix compile error] Signed-off-by: Alexander Graf <agraf@suse.de>
* powerpc: Implement tick broadcast IPI as a fixed IPI messageSrivatsa S. Bhat2014-03-051-0/+1
| | | | | | | | | | | | | | | | | | | For scalability and performance reasons, we want the tick broadcast IPIs to be handled as efficiently as possible. Fixed IPI messages are one of the most efficient mechanisms available - they are faster than the smp_call_function mechanism because the IPI handlers are fixed and hence they don't involve costly operations such as adding IPI handlers to the target CPU's function queue, acquiring locks for synchronization etc. Luckily we have an unused IPI message slot, so use that to implement tick broadcast IPIs efficiently. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> [Functions renamed to tick_broadcast* and Changelog modified by Preeti U. Murthy<preeti@linux.vnet.ibm.com>] Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com> Acked-by: Geoff Levand <geoff@infradead.org> [For the PS3 part] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* cputime: Consolidate vtime handling on context switchFrederic Weisbecker2012-08-201-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | The archs that implement virtual cputime accounting all flush the cputime of a task when it gets descheduled and sometimes set up some ground initialization for the next task to account its cputime. These archs all put their own hooks in their context switch callbacks and handle the off-case themselves. Consolidate this by creating a new account_switch_vtime() callback called in generic code right after a context switch and that these archs must implement to flush the prev task cputime and initialize the next task cputime related state. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
* KVM: PPC: Use clockevent multiplier and shifter for decrementerBharat Bhushan2012-05-061-0/+1
| | | | | | | | | | | | | | | | | Time for which the hrtimer is started for decrementer emulation is calculated using tb_ticks_per_usec. While hrtimer uses the clockevent for DEC reprogramming (if needed) and which calculate timebase ticks using the multiplier and shifter mechanism implemented within clockevent layer. It was observed that this conversion (timebase->time->timebase) are not correct because the mechanism are not consistent. In our setup it adds 2% jitter. With this patch clockevent multiplier and shifter mechanism are used when starting hrtimer for decrementer emulation. Now the jitter is < 0.5%. Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
* powerpc: Remove FW_FEATURE ISERIES from arch codeStephen Rothwell2012-03-211-15/+0
| | | | | | | This is no longer selectable, so just remove all the dependent code. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/time: Optimise decrementer_check_overflowAnton Blanchard2011-11-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | decrementer_check_overflow is called from arch_local_irq_restore so we want to make it as light weight as possible. As such, turn decrementer_check_overflow into an inline function. To avoid a circular mess of includes, separate out the two components of struct decrementer_clock and keep the struct clock_event_device part local to time.c. The fast path improves from: arch_local_irq_restore 0: mflr r0 4: std r0,16(r1) 8: stdu r1,-112(r1) c: stb r3,578(r13) 10: cmpdi cr7,r3,0 14: beq- cr7,24 <.arch_local_irq_restore+0x24> ... 24: addi r1,r1,112 28: ld r0,16(r1) 2c: mtlr r0 30: blr to: arch_local_irq_restore 0: std r30,-16(r1) 4: ld r30,0(r2) 8: stb r3,578(r13) c: cmpdi cr7,r3,0 10: beq- cr7,6c <.arch_local_irq_restore+0x6c> ... 6c: ld r30,-16(r1) 70: blr Unfortunately we still setup a local TOC (due to -mminimal-toc). Yet another sign we should be moving to -mcmodel=medium. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/time: Handle wrapping of decrementerAnton Blanchard2011-11-251-0/+2
| | | | | | | | | | | | | | | | | | | | | When re-enabling interrupts we have code to handle edge sensitive decrementers by resetting the decrementer to 1 whenever it is negative. If interrupts were disabled long enough that the decrementer wrapped to positive we do nothing. This means interrupts can be delayed for a long time until it finally goes negative again. While we hope interrupts are never be disabled long enough for the decrementer to go positive, we have a very good test team that can drive any kernel into the ground. The softlockup data we get back from these fails could be seconds in the future, completely missing the cause of the lockup. We already keep track of the timebase of the next event so use that to work out if we should trigger a decrementer exception. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: stable@kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Account time using timebase rather than PURRPaul Mackerras2010-09-021-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the PURR register for measuring the user and system time used by processes, as well as other related times such as hardirq and softirq times. This turns out to be quite confusing for users because it means that a program will often be measured as taking less time when run on a multi-threaded processor (SMT2 or SMT4 mode) than it does when run on a single-threaded processor (ST mode), even though the program takes longer to finish. The discrepancy is accounted for as stolen time, which is also confusing, particularly when there are no other partitions running. This changes the accounting to use the timebase instead, meaning that the reported user and system times are the actual number of real-time seconds that the program was executing on the processor thread, regardless of which SMT mode the processor is in. Thus a program will generally show greater user and system times when run on a multi-threaded processor than on a single-threaded processor. On pSeries systems on POWER5 or later processors, we measure the stolen time (time when this partition wasn't running) using the hypervisor dispatch trace log. We check for new entries in the log on every entry from user mode and on every transition from kernel process context to soft or hard IRQ context (i.e. when account_system_vtime() gets called). So that we can correctly distinguish time stolen from user time and time stolen from system time, without having to check the log on every exit to user mode, we store separate timestamps for exit to user mode and entry from user mode. On systems that have a SPURR (POWER6 and POWER7), we read the SPURR in account_system_vtime() (as before), and then apportion the SPURR ticks since the last time we read it between scaled user time and scaled system time according to the relative proportions of user time and system time over the same interval. This avoids having to read the SPURR on every kernel entry and exit. On systems that have PURR but not SPURR (i.e., POWER5), we do the same using the PURR rather than the SPURR. This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl for now since it conflicts with the use of the dispatch trace log by the time accounting code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Clean up obsolete code relating to decrementer and timebasePaul Mackerras2010-07-091-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | Since the decrementer and timekeeping code was moved over to using the generic clockevents and timekeeping infrastructure, several variables and functions have been obsolete and effectively unused. This deletes them. In particular, wakeup_decrementer() is no longer needed since the generic code reprograms the decrementer as part of the process of resuming the timekeeping code, which happens during sysdev resume. Thus the wakeup_decrementer calls in the suspend_enter methods for 52xx platforms have been removed. The call in the powermac cpu frequency change code has been replaced by set_dec(1), which will cause a timer interrupt as soon as interrupts are enabled, and the generic code will then reprogram the decrementer with the correct value. This also simplifies the generic_suspend_en/disable_irqs functions and makes them static since they are not referenced outside time.c. The preempt_enable/disable calls are removed because the generic code has disabled all but the boot cpu at the point where these functions are called, so we can't be moved to another cpu. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Eliminate unused do_gtod variablePaul Mackerras2008-11-051-20/+0
| | | | | | | | | Since we started using the generic timekeeping code, we haven't had a powerpc-specific version of do_gettimeofday, and hence there is now nothing that reads the do_gtod variable in arch/powerpc/kernel/time.c. This therefore removes it and the code that sets it. Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc: Move include files to arch/powerpc/include/asmStephen Rothwell2008-08-041-0/+255
from include/asm-powerpc. This is the result of a mkdir arch/powerpc/include/asm git mv include/asm-powerpc/* arch/powerpc/include/asm Followed by a few documentation/comment fixups and a couple of places where <asm-powepc/...> was being used explicitly. Of the latter only one was outside the arch code and it is a driver only built for powerpc. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
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