kernel/arch/powerpc/include/asm/time.h, branch linux-4.16.y

powerpc: Move cpu_has_feature() to a separate file

2016-08-01T01:15:03Z

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 Signed-off-by: Aneesh Kumar K.V [mpe: Rename to cpu_has_feature.h and flesh out change log] Signed-off-by: Michael Ellerman

powerpc: Remove mfvtb()

2016-08-01T01:15:03Z

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 Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman

powerpc/timer: Large Decrementer support

2016-07-05T13:58:53Z

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 Signed-off-by: Balbir Singh Acked-by: Michael Neuling Signed-off-by: Michael Ellerman

powerpc/8xx: remove special handling of CPU6 errata in set_dec()

2016-03-11T23:18:03Z

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 Signed-off-by: Scott Wood

powerpc: Remove broken GregorianDay()

2015-12-16T01:54:04Z

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 Cc: Andrew Morton # as an example of what UBSan finds. Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: rtc-linux@googlegroups.com Signed-off-by: Daniel Axtens Acked-by: Alexandre Belloni Signed-off-by: Michael Ellerman

KVM: PPC: Book3S HV: Accumulate timing information for real-mode code

2015-04-21T13:21:31Z

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 Signed-off-by: Alexander Graf

KVM: PPC: BOOK3S: PR: Emulate virtual timebase register

2014-07-28T13:21:50Z

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 [agraf: fix compile error] Signed-off-by: Alexander Graf

powerpc: Implement tick broadcast IPI as a fixed IPI message

2014-03-05T04:55:04Z

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 [Functions renamed to tick_broadcast* and Changelog modified by Preeti U. Murthy] Signed-off-by: Preeti U. Murthy Acked-by: Geoff Levand [For the PS3 part] Signed-off-by: Benjamin Herrenschmidt

cputime: Consolidate vtime handling on context switch

2012-08-20T11:05:28Z

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 Acked-by: Martin Schwidefsky Cc: Tony Luck Cc: Fenghua Yu Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Heiko Carstens Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra

KVM: PPC: Use clockevent multiplier and shifter for decrementer

2012-05-06T14:19:07Z

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 Signed-off-by: Alexander Graf