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| * | | powerpc/fadump: avoid duplicates in crash memory rangesHari Bathini2017-06-281-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fadump sets up crash memory ranges to be used for creating PT_LOAD program headers in elfcore header. Memory chunk RMA_START through boot memory area size is added as the first memory range because firmware, at the time of crash, moves this memory chunk to different location specified during fadump registration making it necessary to create a separate program header for it with the correct offset. This memory chunk is skipped while setting up the remaining memory ranges. But currently, there is possibility that some of this memory may have duplicate entries like when it is hot-removed and added again. Ensure that no two memory ranges represent the same memory. When 5 lmbs are hot-removed and then hot-plugged before registering fadump, here is how the program headers in /proc/vmcore exported by fadump look like without this change: Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align NOTE 0x0000000000010000 0x0000000000000000 0x0000000000000000 0x0000000000001894 0x0000000000001894 0 LOAD 0x0000000000021020 0xc000000000000000 0x0000000000000000 0x0000000040000000 0x0000000040000000 RWE 0 LOAD 0x0000000040031020 0xc000000000000000 0x0000000000000000 0x0000000010000000 0x0000000010000000 RWE 0 LOAD 0x0000000050040000 0xc000000010000000 0x0000000010000000 0x0000000050000000 0x0000000050000000 RWE 0 LOAD 0x00000000a0040000 0xc000000060000000 0x0000000060000000 0x000000019ffe0000 0x000000019ffe0000 RWE 0 and with this change: Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align NOTE 0x0000000000010000 0x0000000000000000 0x0000000000000000 0x0000000000001894 0x0000000000001894 0 LOAD 0x0000000000021020 0xc000000000000000 0x0000000000000000 0x0000000040000000 0x0000000040000000 RWE 0 LOAD 0x0000000040030000 0xc000000040000000 0x0000000040000000 0x0000000020000000 0x0000000020000000 RWE 0 LOAD 0x0000000060030000 0xc000000060000000 0x0000000060000000 0x000000019ffe0000 0x000000019ffe0000 RWE 0 Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> Reviewed-by: Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/64s: Invalidate ERAT on powersave wakeup for POWER9Benjamin Herrenschmidt2017-06-272-3/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On POWER9 the ERAT may be incorrect on wakeup from some stop states that lose state. This causes random segvs and illegal instructions when these stop states are enabled. This patch invalidates the ERAT on wakeup on POWER9 to prevent this from causing a problem. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Merge comment change with upstream changes] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/tm: Fix commentMichael Neuling2017-06-271-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Update to real function name. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc: Fix asm offsets to point to actual FP and VMX regsMichael Neuling2017-06-271-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The asm code assumes the FP regs are at the start of fp_state. While this is true now, it may not always be the case and there is nothing enforcing it. This fixes the asm-offsets to point to the actual FP registers inside the fp_state. Similarly for VMX. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc: Fix /proc/cpuinfo revision for POWER9 DD2Michael Neuling2017-06-271-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The P9 PVR bits 12-15 don't indicate a revision but instead different chip configurations. From BookIV we have: Bits Configuration 0 : Scale out 12 cores 1 : Scale out 24 cores 2 : Scale up 12 cores 3 : Scale up 24 cores DD1 doesn't use this but DD2 does. Linux will mostly use the "Scale out 24 core" configuration (ie. SMT4 not SMT8) which results in a PVR of 0x004e1200. The reported revision in /proc/cpuinfo is hence reported incorrectly as "18.0". This patch fixes this to mask off only the relevant bits for the major revision (ie. bits 8-11) for POWER9. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc: Convert VDSO update function to use new update_vsyscall interfacePaul Mackerras2017-06-221-16/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This converts the powerpc VDSO time update function to use the new interface introduced in commit 576094b7f0aa ("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>
| * | | powerpc/time: Fix tracing in time.cSantosh Sivaraj2017-06-212-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Rename slb_allocate_realmode() to slb_allocate()Michael Ellerman2017-06-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Rename slb_miss_realmode() to slb_miss_common()Michael Ellerman2017-06-211-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Use BRANCH_TO_COMMON() for slb_miss_realmodeMichael Ellerman2017-06-211-38/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Avoid r3 save/restore in SLB miss handlerNicholas Piggin2017-06-201-15/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: SLB miss already has CTR saved for relocatable kernelNicholas Piggin2017-06-201-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Avoid saving faulting address into EX_DAR in SLB missNicholas Piggin2017-06-201-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s/idle: Predict HMI wakeup as unlikelyNicholas Piggin2017-06-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s/idle: Avoid SRR usage in idle sleep/wake pathsNicholas Piggin2017-06-192-30/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s/idle: Branch to handler with virtual mode offsetNicholas Piggin2017-06-191-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Don't unbalance the return branch predictor in __replay_interrupt()Nicholas Piggin2017-06-191-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: msgclr when handling doorbell exceptions from system resetNicholas Piggin2017-06-192-2/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s/idle: Process interrupts from system reset wakeupNicholas Piggin2017-06-191-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s/idle: Move soft interrupt mask logic into C codeNicholas Piggin2017-06-192-68/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Avoid cpabort in context switch when possibleNicholas Piggin2017-06-152-10/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64: Drop explicit hwsync in context switchNicholas Piggin2017-06-151-6/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64: Drop reservation-clearing ldarx in context switchNicholas Piggin2017-06-151-8/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Leave interrupts hard enabled in context switch for radixNicholas Piggin2017-06-152-6/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64: Avoid restore_math call if possible in syscall exitNicholas Piggin2017-06-152-19/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | powerpc/64s: Optimize hypercall/syscall entryNicholas Piggin2017-06-151-37/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After bc3551257a ("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>
| * | | Revert "powerpc: Handle simultaneous interrupts at once"Michael Ellerman2017-06-151-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 45cb08f4791ce6a15c54598b4cb73db4b4b8294f. 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>
| * | | powerpc/64s: Machine check handle ifetch from foreign real address for POWER9Nicholas Piggin2017-06-062-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The i-side 0111b machine check, which is "Instruction Fetch to foreign address space", was missed by 7b9f71f974 ("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: 7b9f71f974a1 ("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>
| * | | powerpc/fadump: Set an upper limit for boot memory sizeHari Bathini2017-06-021-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | By default, 5% of system RAM is reserved for preserving boot memory. Alternatively, a user can specify the amount of memory to reserve. See Documentation/powerpc/firmware-assisted-dump.txt for details. In addition to the memory reserved for preserving boot memory, some more memory is reserved, to save HPTE region, CPU state data and ELF core headers. Memory Reservation during first kernel looks like below: Low memory Top of memory 0 boot memory size | | | |<--Reserved dump area -->| V V | Permanent Reservation V +-----------+----------/ /----------+---+----+-----------+----+ | | |CPU|HPTE| DUMP |ELF | +-----------+----------/ /----------+---+----+-----------+----+ | ^ | | \ / ------------------------------------------- Boot memory content gets transferred to reserved area by firmware at the time of crash This implicitly means that the sum of the sizes of boot memory, CPU state data, HPTE region, DUMP preserving area and ELF core headers can't be greater than the total memory size. But currently, a user is allowed to specify any value as boot memory size. So, the above rule is violated when a boot memory size around 50% of the total available memory is specified. As the kernel is not handling this currently, it may lead to undefined behavior. Fix it by setting an upper limit for boot memory size to 25% of the total available memory. Also, instead of using memblock_end_of_DRAM(), which doesn't take the holes, if any, in the memory layout into account, use memblock_phys_mem_size() to calculate the percentage of total available memory. Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/fadump: Update comment about offset where fadump is reservedHari Bathini2017-06-021-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With commit f6e6bedb7731 ("powerpc/fadump: Reserve memory at an offset closer to bottom of RAM"), memory for fadump is no longer reserved at the top of RAM. But there are still a few places which say so. Change them appropriately. Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/fadump: Add a warning when 'fadump_reserve_mem=' is usedHari Bathini2017-06-021-0/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With commit 11550dc0a00b ("powerpc/fadump: reuse crashkernel parameter for fadump memory reservation"), 'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter. Add a warning if 'fadump_reserve_mem=' is still used. Fixes: 11550dc0a00b ("powerpc/fadump: reuse crashkernel parameter for fadump memory reservation") Suggested-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> [mpe: Unsplit long printk strings] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/fadump: Return error when fadump registration failsMichal Suchanek2017-06-021-8/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - log an error message when registration fails and no error code listed in the switch is returned - translate the hv error code to posix error code and return it from fw_register - return the posix error code from fw_register to the process writing to sysfs - return EEXIST on re-registration - return success on deregistration when fadump is not registered - return ENODEV when no memory is reserved for fadump Signed-off-by: Michal Suchanek <msuchanek@suse.de> Tested-by: Hari Bathini <hbathini@linux.vnet.ibm.com> [mpe: Use pr_err() to shrink the error print] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc: Handle simultaneous interrupts at onceChristophe Leroy2017-06-021-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It often happens to have simultaneous interrupts, for instance when having double Ethernet attachment. With the current implementation, we suffer the cost of kernel entry/exit for each interrupt. This patch introduces a loop in __do_irq() to handle all interrupts at once before returning. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/40x: Clear MSR_DR in one insn instead of twoChristophe Leroy2017-06-021-4/+2
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc: Link warning for orphan sectionsNicholas Piggin2017-05-301-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add --orphan-handling=warn to final link flags. This ensures we can handle all sections explicitly. This would have caught subtle breakage such as 7de3b27bac47da9de08409df1d69664acbb72197 at build-time. Also bring existing orphan sections into the fold: - .text.hot and .text.unlikely are compiler generated sections. - .sdata2, .dynsbss, .plt are used by PPC32 - We previously did not specify DWARF_DEBUG or STABS_DEBUG - DWARF_DEBUG did not include all DWARF sections that can be emitted - A number of sections are unused and can be discarded. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/64: Tool to check head sections location sanityNicholas Piggin2017-05-301-22/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use a tool to check that the location of "fixed sections" are where we expected them to be, which catches cases the linker script can't (stubs being added to start of .text section), and which ends up being neater. Sample output: ERROR: start_text address is c000000000008100, should be c000000000008000 ERROR: see comments in arch/powerpc/tools/head_check.sh Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Fold in fix from Nick for 4.6 era toolchains] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/64: Handle linker stubs in low .text codeNicholas Piggin2017-05-301-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Very large kernels may require linker stubs for branches from HEAD text code. The linker may place these stubs before the HEAD text sections, which breaks the assumption that HEAD text is located at 0 (or the .text section being located at 0x7000/0x8000 on Book3S kernels). Provide an option to create a small section just before the .text section with an empty 256 - 4 bytes, and adjust the start of the .text section to match. The linker will tend to put stubs in that section and not break our relative-to-absolute offset assumptions. This causes a small waste of space on common kernels, but allows large kernels to build and boot. For now, it is an EXPERT config option, defaulting to =n, but a reference is provided for it in the build-time check for such breakage. This is good enough for allyesconfig and custom users / hackers. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/64: Place sfpr section explicitly with the linker scriptNicholas Piggin2017-05-301-0/+8
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/[booke|4xx]: Don't clobber TCR[WP] when setting TCR[DIE]Ivan Mikhaylov2017-05-301-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Prevent a kernel panic caused by unintentionally clearing TCR watchdog bits. At this point in the kernel boot, the watchdog may have already been enabled by u-boot. The original code's attempt to write to the TCR register results in an inadvertent clearing of the watchdog configuration bits, causing the 476 to reset. Signed-off-by: Ivan Mikhaylov <ivan@de.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/powernv/idle: Use Requested Level for restoring state on P9 DD1Gautham R. Shenoy2017-05-302-1/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On Power9 DD1 due to a hardware bug the Power-Saving Level Status field (PLS) of the PSSCR for a thread waking up from a deep state can under-report if some other thread in the core is in a shallow stop state. The scenario in which this can manifest is as follows: 1) All the threads of the core are in deep stop. 2) One of the threads is woken up. The PLS for this thread will correctly reflect that it is waking up from deep stop. 3) The thread that has woken up now executes a shallow stop. 4) When some other thread in the core is woken, its PLS will reflect the shallow stop state. Thus, the subsequent thread for which the PLS is under-reporting the wakeup state will not restore the hypervisor resources. Hence, on DD1 systems, use the Requested Level (RL) field as a workaround to restore the contents of the hypervisor resources on the wakeup from the stop state. Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/powernv/idle: Restore LPCR on wakeup from deep-stopGautham R. Shenoy2017-05-301-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On wakeup from a deep stop state which is supposed to lose the hypervisor state, we don't restore the LPCR to the old value but set it to a "sane" value via cur_cpu_spec->cpu_restore(). The problem is that the "sane" value doesn't include UPRT and the HR bits which are required to run correctly in Radix mode. Fix this on POWER9 onwards by restoring the LPCR value whatever it was before executing the stop instruction. Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | powerpc/powernv/idle: Decouple Timebase restore & Per-core SPRs restoreGautham R. Shenoy2017-05-301-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On POWER8, in case of - nap: both timebase and hypervisor state is retained. - fast-sleep: timebase is lost. But the hypervisor state is retained. - winkle: timebase and hypervisor state is lost. Hence, the current code for handling exit from a idle state assumes that if the timebase value is retained, then so is the hypervisor state. Thus, the current code doesn't restore per-core hypervisor state in such cases. But that is no longer the case on POWER9 where we do have stop states in which timebase value is retained, but the hypervisor state is lost. So we have to ensure that the per-core hypervisor state gets restored in such cases. Fix this by ensuring that even in the case when timebase is retained, we explicitly check if we are waking up from a deep stop that loses per-core hypervisor state (indicated by cr4 being eq or gt), and if this is the case, we restore the per-core hypervisor state. Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* | | | Merge tag 'dma-mapping-4.13' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds2017-07-063-27/+24
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull dma-mapping infrastructure from Christoph Hellwig: "This is the first pull request for the new dma-mapping subsystem In this new subsystem we'll try to properly maintain all the generic code related to dma-mapping, and will further consolidate arch code into common helpers. This pull request contains: - removal of the DMA_ERROR_CODE macro, replacing it with calls to ->mapping_error so that the dma_map_ops instances are more self contained and can be shared across architectures (me) - removal of the ->set_dma_mask method, which duplicates the ->dma_capable one in terms of functionality, but requires more duplicate code. - various updates for the coherent dma pool and related arm code (Vladimir) - various smaller cleanups (me)" * tag 'dma-mapping-4.13' of git://git.infradead.org/users/hch/dma-mapping: (56 commits) ARM: dma-mapping: Remove traces of NOMMU code ARM: NOMMU: Set ARM_DMA_MEM_BUFFERABLE for M-class cpus ARM: NOMMU: Introduce dma operations for noMMU drivers: dma-mapping: allow dma_common_mmap() for NOMMU drivers: dma-coherent: Introduce default DMA pool drivers: dma-coherent: Account dma_pfn_offset when used with device tree dma: Take into account dma_pfn_offset dma-mapping: replace dmam_alloc_noncoherent with dmam_alloc_attrs dma-mapping: remove dmam_free_noncoherent crypto: qat - avoid an uninitialized variable warning au1100fb: remove a bogus dma_free_nonconsistent call MAINTAINERS: add entry for dma mapping helpers powerpc: merge __dma_set_mask into dma_set_mask dma-mapping: remove the set_dma_mask method powerpc/cell: use the dma_supported method for ops switching powerpc/cell: clean up fixed mapping dma_ops initialization tile: remove dma_supported and mapping_error methods xen-swiotlb: remove xen_swiotlb_set_dma_mask arm: implement ->dma_supported instead of ->set_dma_mask mips/loongson64: implement ->dma_supported instead of ->set_dma_mask ...
| * | | | powerpc: merge __dma_set_mask into dma_set_maskChristoph Hellwig2017-06-281-9/+4
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de>
| * | | | dma-mapping: remove the set_dma_mask methodChristoph Hellwig2017-06-281-4/+0
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de>
| * | | | powerpc: implement ->mapping_errorChristoph Hellwig2017-06-282-14/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DMA_ERROR_CODE is going to go away, so don't rely on it. Instead define a ->mapping_error method for all IOMMU based dma operation instances. The direct ops don't ever return an error and don't need a ->mapping_error method. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
* | | | | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2017-07-062-0/+4
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull KVM updates from Paolo Bonzini: "PPC: - Better machine check handling for HV KVM - Ability to support guests with threads=2, 4 or 8 on POWER9 - Fix for a race that could cause delayed recognition of signals - Fix for a bug where POWER9 guests could sleep with interrupts pending. ARM: - VCPU request overhaul - allow timer and PMU to have their interrupt number selected from userspace - workaround for Cavium erratum 30115 - handling of memory poisonning - the usual crop of fixes and cleanups s390: - initial machine check forwarding - migration support for the CMMA page hinting information - cleanups and fixes x86: - nested VMX bugfixes and improvements - more reliable NMI window detection on AMD - APIC timer optimizations Generic: - VCPU request overhaul + documentation of common code patterns - kvm_stat improvements" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (124 commits) Update my email address kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS x86: kvm: mmu: use ept a/d in vmcs02 iff used in vmcs12 kvm: x86: mmu: allow A/D bits to be disabled in an mmu x86: kvm: mmu: make spte mmio mask more explicit x86: kvm: mmu: dead code thanks to access tracking KVM: PPC: Book3S: Fix typo in XICS-on-XIVE state saving code KVM: PPC: Book3S HV: Close race with testing for signals on guest entry KVM: PPC: Book3S HV: Simplify dynamic micro-threading code KVM: x86: remove ignored type attribute KVM: LAPIC: Fix lapic timer injection delay KVM: lapic: reorganize restart_apic_timer KVM: lapic: reorganize start_hv_timer kvm: nVMX: Check memory operand to INVVPID KVM: s390: Inject machine check into the nested guest KVM: s390: Inject machine check into the guest tools/kvm_stat: add new interactive command 'b' tools/kvm_stat: add new command line switch '-i' tools/kvm_stat: fix error on interactive command 'g' KVM: SVM: suppress unnecessary NMI singlestep on GIF=0 and nested exit ...
| * | | | | powerpc/book3s: EXPORT_SYMBOL_GPL machine_check_print_event_infoMahesh Salgaonkar2017-06-211-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It will be used in arch/powerpc/kvm/book3s_hv.c KVM module. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | | | KVM: PPC: Book3S HV: Add new capability to control MCE behaviourAravinda Prasad2017-06-211-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This introduces a new KVM capability to control how KVM behaves on machine check exception (MCE) in HV KVM guests. If this capability has not been enabled, KVM redirects machine check exceptions to guest's 0x200 vector, if the address in error belongs to the guest. With this capability enabled, KVM will cause a guest exit with the exit reason indicating an NMI. The new capability is required to avoid problems if a new kernel/KVM is used with an old QEMU, running a guest that doesn't issue "ibm,nmi-register". As old QEMU does not understand the NMI exit type, it treats it as a fatal error. However, the guest could have handled the machine check error if the exception was delivered to guest's 0x200 interrupt vector instead of NMI exit in case of old QEMU. [paulus@ozlabs.org - Reworded the commit message to be clearer, enable only on HV KVM.] Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | | | KVM: PPC: Book3S HV: Virtualize doorbell facility on POWER9Paul Mackerras2017-06-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On POWER9, we no longer have the restriction that we had on POWER8 where all threads in a core have to be in the same partition, so the CPU threads are now independent. However, we still want to be able to run guests with a virtual SMT topology, if only to allow migration of guests from POWER8 systems to POWER9. A guest that has a virtual SMT mode greater than 1 will expect to be able to use the doorbell facility; it will expect the msgsndp and msgclrp instructions to work appropriately and to be able to read sensible values from the TIR (thread identification register) and DPDES (directed privileged doorbell exception status) special-purpose registers. However, since each CPU thread is a separate sub-processor in POWER9, these instructions and registers can only be used within a single CPU thread. In order for these instructions to appear to act correctly according to the guest's virtual SMT mode, we have to trap and emulate them. We cause them to trap by clearing the HFSCR_MSGP bit in the HFSCR register. The emulation is triggered by the hypervisor facility unavailable interrupt that occurs when the guest uses them. To cause a doorbell interrupt to occur within the guest, we set the DPDES register to 1. If the guest has interrupts enabled, the CPU will generate a doorbell interrupt and clear the DPDES register in hardware. The DPDES hardware register for the guest is saved in the vcpu->arch.vcore->dpdes field. Since this gets written by the guest exit code, other VCPUs wishing to cause a doorbell interrupt don't write that field directly, but instead set a vcpu->arch.doorbell_request flag. This is consumed and set to 0 by the guest entry code, which then sets DPDES to 1. Emulating reads of the DPDES register is somewhat involved, because it requires reading the doorbell pending interrupt status of all of the VCPU threads in the virtual core, and if any of those VCPUs are running, their doorbell status is only up-to-date in the hardware DPDES registers of the CPUs where they are running. In order to get a reasonable approximation of the current doorbell status, we send those CPUs an IPI, causing an exit from the guest which will update the vcpu->arch.vcore->dpdes field. We then use that value in constructing the emulated DPDES register value. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
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