- Jun 22, 2017
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Paul Mackerras authored
This converts the powerpc VDSO time update function to use the new interface introduced in commit 576094b7 ("time: Introduce new GENERIC_TIME_VSYSCALL", 2012-09-11). Where the old interface gave us the time as of the last update in seconds and whole nanoseconds, with the new interface we get the nanoseconds part effectively in a binary fixed-point format with tk->tkr_mono.shift bits to the right of the binary point. With the old interface, the fractional nanoseconds got truncated, meaning that the value returned by the VDSO clock_gettime function would have about 1ns of jitter in it compared to the value computed by the generic timekeeping code in the kernel. The powerpc VDSO time functions (clock_gettime and gettimeofday) already work in units of 2^-32 seconds, or 0.23283 ns, because that makes it simple to split the result into seconds and fractional seconds, and represent the fractional seconds in either microseconds or nanoseconds. This is good enough accuracy for now, so this patch avoids changing how the VDSO works or the interface in the VDSO data page. This patch converts the powerpc update_vsyscall_old to be called update_vsyscall and use the new interface. We convert the fractional second to units of 2^-32 seconds without truncating to whole nanoseconds. (There is still a conversion to whole nanoseconds for any legacy users of the vdso_data/systemcfg stamp_xtime field.) In addition, this improves the accuracy of the computation of tb_to_xs for those systems with high-frequency timebase clocks (>= 268.5 MHz) by doing the right shift in two parts, one before the multiplication and one after, rather than doing the right shift before the multiplication. (We can't do all of the right shift after the multiplication unless we use 128-bit arithmetic.) Signed-off-by:
Paul Mackerras <paulus@ozlabs.org> Acked-by:
John Stultz <john.stultz@linaro.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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- Jun 21, 2017
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Santosh Sivaraj authored
Since trace_clock is in a different file and already marked with notrace, enable tracing in time.c by removing it from the disabled list in Makefile. Also annotate clocksource read functions and sched_clock with notrace. Testing: Timer and ftrace selftests run with different trace clocks. Acked-by:
Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by:
Santosh Sivaraj <santosh@fossix.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Michael Ellerman authored
As for slb_miss_realmode(), rename slb_allocate_realmode() to avoid confusion over whether it runs in real or virtual mode - it runs in both. Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Reviewed-by:
Nicholas Piggin <npiggin@gmail.com>
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Michael Ellerman authored
slb_miss_realmode() doesn't always runs in real mode, which is what the name implies. So rename it to avoid confusing people. Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Reviewed-by:
Nicholas Piggin <npiggin@gmail.com>
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Michael Ellerman authored
All the callers of slb_miss_realmode currently open code the #ifndef CONFIG_RELOCATABLE check and the branch via CTR in the RELOCATABLE case. We have a macro to do this, BRANCH_TO_COMMON(), so use it. Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Reviewed-by:
Nicholas Piggin <npiggin@gmail.com>
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- Jun 20, 2017
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Nicholas Piggin authored
Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
EX_R3 is used only for a small section of the bad stack handler. Merge it with EX_DAR. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
EX_LR is used only for a small section of the SLB miss handler. Merge it with EX_DAR. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
Rather than open-coding it 4 times. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> [mpe: Move __ASSEMBLY__ guards into head-64.h where they're really needed] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
The SLB miss handler uses r3 for the faulting address but r12 is mostly able to be freed up to save r3 in. It just requires SRR1 be reloaded again on error. It would be more conventional to use r12 for SRR1 (and use r11 to save r3), but slb_allocate_realmode clobbers r11 and not r12. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
The EXCEPTION_PROLOG_1 used by SLB miss already saves CTR when the kernel is built with CONFIG_RELOCATABLE. So it does not have to be saved and reloaded when branching to slb_miss_realmode. It can be restored from the PACA as usual. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
The EX_DAR save area is only used in exceptional cases. With r3 no longer clobbered by slb_allocate_realmode, saving faulting address to EX_DAR can be deferred to those cases. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
One fewer registers clobbered by this function means the SLB miss handler can save one fewer. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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- Jun 19, 2017
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Nicholas Piggin authored
In the idle sleep/wake code we know that MSR[EE] is clear, so we can avoid 2 x mfmsr and 2 x mtmsr by calling the double-underscore versions of the run latch routines which assume interrupts are already disabled. Acked-by:
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
In a busy system, idle wakeups can be expected from IPIs and device interrupts. Reviewed-by:
Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
Idle code now always runs at the 0xc... effective address whether in real or virtual mode. This means rfid can be ditched, along with a lot of SRR manipulations. In the wakeup path, carry SRR1 around in r12. Use mtmsrd to change MSR states as required. This also balances the return prediction for the idle call, by doing blr rather than rfid to return to the idle caller. On POWER9, 2-process context switch on different cores, with snooze disabled, increases performance by 2%. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> [mpe: Incorporate v2 fixes from Nick] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
Have the system reset idle wakeup handlers branched to in real mode with the 0xc... kernel address applied. This allows simplifications of avoiding rfid when switching to virtual mode in the wakeup handler. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
The __replay_interrupt() code is branched to with bl, but the caller is returned to directly with rfid from the interrupt. Instead, rfid to a stub that returns to the caller with blr, which should keep the return branch predictor balanced. Reviewed-by:
Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
msgsnd doorbell exceptions are cleared when the doorbell interrupt is taken. However if a doorbell exception causes a system reset interrupt wake from power saving state, the message is not cleared. Processing the doorbell from the system reset interrupt requires msgclr to avoid taking the exception again. Testing this plus the previous wakup direct patch gives: original wakeup direct msgclr Different threads, same core: 315k/s 264k/s 345k/s Different cores: 235k/s 242k/s 242k/s Net speedup is +10% for same core, and +3% for different core. Reviewed-by:
Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
When the CPU wakes from low power state, it begins at the system reset interrupt with the exception that caused the wakeup encoded in SRR1. Today, powernv idle wakeup ignores the wakeup reason (except a special case for HMI), and the regular interrupt corresponding to the exception will fire after the idle wakeup exits. Change this to replay the interrupt from the idle wakeup before interrupts are hard-enabled. Test on POWER8 of context_switch selftests benchmark with polling idle disabled (e.g., always nap, giving cross-CPU IPIs) gives the following results: original wakeup direct Different threads, same core: 315k/s 264k/s Different cores: 235k/s 242k/s There is a slowdown for doorbell IPI (same core) case because system reset wakeup does not clear the message and the doorbell interrupt fires again needlessly. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
Rather than concern ourselves with any soft-mask logic in the CPU hotplug handler, just hard disable interrupts. This ensures there are no lazy-irqs pending, which means we can call directly to idle instruction in order to sleep. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
This simplifies the asm and fixes irq-off tracing over sleep instructions. Also move powersave_nap check for POWER8 into C code, and move PSSCR register value calculation for POWER9 into C. Reviewed-by:
Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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- Jun 15, 2017
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Murilo Opsfelder Araujo authored
drivers/watchdog/wdrtas.c uses symbols defined in arch/powerpc/kernel/rtas.c, which are exported iff CONFIG_PPC_RTAS is selected. Building wdrtas.c without setting CONFIG_PPC_RTAS throws the following errors: ERROR: ".rtas_token" [drivers/watchdog/wdrtas.ko] undefined! ERROR: "rtas_data_buf" [drivers/watchdog/wdrtas.ko] undefined! ERROR: "rtas_data_buf_lock" [drivers/watchdog/wdrtas.ko] undefined! ERROR: ".rtas_get_sensor" [drivers/watchdog/wdrtas.ko] undefined! ERROR: ".rtas_call" [drivers/watchdog/wdrtas.ko] undefined! This was identified during a randconfig build where CONFIG_WATCHDOG_RTAS=m and CONFIG_PPC_RTAS was not set. Logs are here: http://kisskb.ellerman.id.au/kisskb/buildresult/12982152/ This patch fixes the issue by updating CONFIG_WATCHDOG_RTAS to depend on just CONFIG_PPC_RTAS, removing COMPILE_TEST entirely. Signed-off-by:
Murilo Opsfelder Araujo <mopsfelder@gmail.com> Reviewed-by:
Guenter Roeck <linux@roeck-us.net> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
The ISA v3.0B copy-paste facility only requires cpabort when switching to a process that has foreign real addresses mapped (direct access to accelerators), to clear a potential copy buffer filled by a previous thread. There is no accelerator driver implemented yet, so cpabort can be removed. It can be be re-added when a driver is implemented. POWER9 DD1 requires the copy buffer to always be cleared on context switch, but if accelerators are not in use, then an unpaired copy from a dummy region is sufficient to clear data out of the copy buffer. This increases context switch performance by about 5% on POWER9. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
The sync (aka. hwsync, aka. heavyweight sync) in the context switch code to prevent MMIO access being reordered from the point of view of a single process if it gets migrated to a different CPU is not required because there is an hwsync performed earlier in the context switch path. Comment this so it's clear enough if anything changes on the scheduler or the powerpc sides. Remove the hwsync from _switch. This improves context switch performance by 2-3% on POWER8. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Acked-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
There is no need to explicitly break the reservation in _switch, because we are guaranteed that the context switch path will include a larx/stcx. Comment the guarantee and remove the reservation clear from _switch. This is worth 1-2% in context switch performance. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
Commit 4387e9ff25 ("[POWERPC] Fix PMU + soft interrupt disable bug") hard disabled interrupts over the low level context switch, because the SLB management can't cope with a PMU interrupt accesing the stack in that window. Radix based kernel mapping does not use the SLB so it does not require interrupts hard disabled here. This is worth 1-2% in context switch performance on POWER9. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
The syscall exit code that branches to restore_math is quite heavy on Book3S, consisting of 2 mtmsr instructions. Threads that don't use both FP and vector can get caught here if the kernel ever uses FP or vector. Lazy-FP/vec context switching also trips this case. So check for lazy FP and vector before switching RI for restore_math. Move most of this case out of line. For threads that do want to restore math registers, the MSR switches are still suboptimal. Future direction may be to use a soft-RI bit to avoid MSR switches in kernel (similar to soft-EE), but for now at least the no-restore POWER9 context switch rate increases by about 5% due to sched_yield(2) return performance. I haven't constructed a test to measure the syscall cost. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
After bc355125 ("powerpc/64: Allow for relocation-on interrupts from guest to host"), a getppid() system call goes from 307 cycles to 358 cycles (+17%) on POWER8. This is due significantly to the scratch SPR used by the hypercall check. It turns out there are a some volatile registers common to both system call and hypercall (in particular, r12, cr0, ctr), which can be used to avoid the SPR and some other overheads. This brings getppid to 320 cycles (+4%). Testing hcall entry performance by running "sc 1" in guest userspace before this patch is 854 cycles, afterwards is 826. Also a small win there. POWER9 syscall is improved by about the same amount, hcall not tested. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Michael Ellerman authored
Currently we map the whole linear mapping with PAGE_KERNEL_X. Instead we should check if the page overlaps the kernel text and only then add PAGE_KERNEL_X. Note that we still use 1G pages if they're available, so this will typically still result in a 1G executable page at KERNELBASE. So this fix is primarily useful for catching stray branches to high linear mapping addresses. Without this patch, we can execute at 1G in xmon using: 0:mon> m c000000040000000 c000000040000000 00 l c000000040000000 00000000 01006038 c000000040000004 00000000 2000804e c000000040000008 00000000 x 0:mon> di c000000040000000 c000000040000000 38600001 li r3,1 c000000040000004 4e800020 blr 0:mon> p c000000040000000 return value is 0x1 After we get a 400 as expected: 0:mon> p c000000040000000 *** 400 exception occurred Fixes: 2bfd65e4 ("powerpc/mm/radix: Add radix callbacks for early init routines") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Reviewed-by:
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by:
Balbir Singh <bsingharora@gmail.com>
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Michael Ellerman authored
This reverts commit 45cb08f4 . For some reason this is causing IRQ problems on Freescale Book3E machines, eg on my p5020ds: irq 25: nobody cared (try booting with the "irqpoll" option) CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc3-gcc-6.3.1-00037-g45cb08f4791c #624 Call Trace: [c0000000fffdbb10] [c00000000049962c] .dump_stack+0xa8/0xe8 (unreliable) [c0000000fffdbba0] [c0000000000babf4] .__report_bad_irq+0x54/0x140 [c0000000fffdbc40] [c0000000000bb11c] .note_interrupt+0x324/0x380 [c0000000fffdbd00] [c0000000000b7110] .handle_irq_event_percpu+0x68/0x88 [c0000000fffdbd90] [c0000000000b718c] .handle_irq_event+0x5c/0xa8 [c0000000fffdbe10] [c0000000000bc01c] .handle_fasteoi_irq+0xe4/0x298 [c0000000fffdbe90] [c0000000000b59c4] .generic_handle_irq+0x50/0x74 [c0000000fffdbf10] [c0000000000075d8] .__do_irq+0x74/0x1f0 [c0000000fffdbf90] [c0000000000189f8] .call_do_irq+0x14/0x24 [c0000000f7173060] [c0000000000077e4] .do_IRQ+0x90/0x120 [c0000000f7173100] [c00000000001d93c] exc_0x500_common+0xfc/0x100 --- interrupt: 501 at .prepare_to_wait_event+0xc/0x14c LR = .fsl_elbc_run_command+0xc8/0x23c [c0000000f71734d0] [c00000000065f418] .nand_reset+0xb8/0x168 [c0000000f7173560] [c00000000065fec4] .nand_scan_ident+0x2b0/0x1638 [c0000000f7173650] [c000000000666cd8] .fsl_elbc_nand_probe+0x34c/0x5f0 ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300) [c0000000f7173750] [c0000000005a3c60] .platform_drv_probe+0x64/0xb0 [c0000000f71737d0] [c0000000005a12e0] .really_probe+0x290/0x334 [c0000000f7173870] [c0000000005a14a0] .__driver_attach+0x11c/0x120 [c0000000f7173900] [c00000000059e6a0] .bus_for_each_dev+0x98/0xfc [c0000000f71739a0] [c0000000005a0b3c] .driver_attach+0x34/0x4c [c0000000f7173a20] [c0000000005a04b0] .bus_add_driver+0x1ac/0x2e0 [c0000000f7173ac0] [c0000000005a2170] .driver_register+0x94/0x160 [c0000000f7173b40] [c0000000005a3be0] .__platform_driver_register+0x60/0x7c [c0000000f7173bc0] [c000000000d6aab4] .fsl_elbc_nand_driver_init+0x24/0x38 [c0000000f7173c30] [c000000000001934] .do_one_initcall+0x68/0x1b8 [c0000000f7173d00] [c000000000d210f8] .kernel_init_freeable+0x260/0x338 [c0000000f7173db0] [c0000000000021b0] .kernel_init+0x20/0xe70 [c0000000f7173e30] [c0000000000009bc] .ret_from_kernel_thread+0x58/0x9c handlers: [<c000000000ed85c8>] .fsl_lbc_ctrl_irq Disabling IRQ #25 Ben also had concerns with the implementation being potentially slow on some PICs, so revert it for now. Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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- Jun 06, 2017
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Nicholas Piggin authored
The i-side 0111b machine check, which is "Instruction Fetch to foreign address space", was missed by 7b9f71f9 ("powerpc/64s: POWER9 machine check handler"). The POWER9 processor core considers host real addresses with a nonzero value in RA(8:12) as foreign address space, accessible only by the copy and paste instructions. The copy and paste instruction pair can be used to invoke the Nest accelerators via the Virtual Accelerator Switchboard (VAS). It is an error for any regular load/store or ifetch to go to a foreign addresses. When relocation is on, this causes an MMU exception. When relocation is off, a machine check exception. It is possible to trigger this machine check by branching to a foreign address with MSR[IR]=0. Fixes: 7b9f71f9 ("powerpc/64s: POWER9 machine check handler") Reported-by:
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Dan Carpenter authored
We should unlock if get_cxl_adapter() fails. Fixes: 594ff7d0 ("cxl: Support to flash a new image on the adapter from a guest") Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Acked-by:
Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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- Jun 05, 2017
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Christophe Leroy authored
These two functions implement the same semantics, so unify their naming so we can share code that calls them. The longer name is more descriptive so use it. Signed-off-by:
Christophe Leroy <christophe.leroy@c-s.fr> Acked-by:
Balbir Singh <bsingharora@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Balbir Singh authored
Add __GFP_ACCOUNT to __hugepte_alloc() Signed-off-by:
Balbir Singh <bsingharora@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Balbir Singh authored
Add support in pte_alloc_one() and pgd_alloc() by passing __GFP_ACCOUNT in the flags Signed-off-by:
Balbir Singh <bsingharora@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Balbir Singh authored
Introduce a helper pgtable_gfp_flags() which just returns the current gfp flags and adds __GFP_ACCOUNT to account for page table allocation. The generic helper is added to include/asm/pgalloc.h and has two variants - WARNING ugly bits ahead 1. If the header is included from a module, no check for mm == &init_mm is done, since init_mm is not exported 2. For kernel includes, the check is done and required see (3e79ec7d arch: x86: charge page tables to kmemcg) The fundamental assumption is that no module should be doing pgd/pud/pmd and pte alloc's on behalf of init_mm directly. NOTE: This adds an overhead to pmd/pud/pgd allocations similar to x86. The other alternative was to implement pmd_alloc_kernel/pud_alloc_kernel and pgd_alloc_kernel with their offset variants. For 4k page size, pte_alloc_one no longer calls pte_alloc_one_kernel. Signed-off-by:
Balbir Singh <bsingharora@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Balbir Singh authored
Currently in hpte_need_flush() if there is no batch pending we always do a global TLB flush, which is inefficient if the mm has never run on another thread. Instead do the same check that __flush_tlb_pending() does and check if a local flush is sufficient when batch->active is false. Instead of open-coding it we use mm_is_thread_local(). Signed-off-by:
Balbir Singh <bsingharora@gmail.com> [mpe: Don't use a local, just inline mm_is_thread_local()] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Yang Li authored
Signed-off-by:
Li Yang <leoyang.li@nxp.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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