linux-stable.git/arch/powerpc/platforms, branch linux-5.2.y Linux kernel stable tree powerpc/pseries: correctly track irq state in default idle 2019-10-07T16:59:18+00:00 Nathan Lynch nathanl@linux.ibm.com 2019-09-10T22:52:44+00:00 112f51caf1b648b302f8345d188206478635ddea [ Upstream commit 92c94dfb69e350471473fd3075c74bc68150879e ] prep_irq_for_idle() is intended to be called before entering H_CEDE (and it is used by the pseries cpuidle driver). However the default pseries idle routine does not call it, leading to mismanaged lazy irq state when the cpuidle driver isn't in use. Manifestations of this include: * Dropped IPIs in the time immediately after a cpu comes online (before it has installed the cpuidle handler), making the online operation block indefinitely waiting for the new cpu to respond. * Hitting this WARN_ON in arch_local_irq_restore(): /* * We should already be hard disabled here. We had bugs * where that wasn't the case so let's dbl check it and * warn if we are wrong. Only do that when IRQ tracing * is enabled as mfmsr() can be costly. */ if (WARN_ON_ONCE(mfmsr() & MSR_EE)) __hard_irq_disable(); Call prep_irq_for_idle() from pseries_lpar_idle() and honor its result. Fixes: 363edbe2614a ("powerpc: Default arch idle could cede processor on pseries") Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190910225244.25056-1-nathanl@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 92c94dfb69e350471473fd3075c74bc68150879e ]

prep_irq_for_idle() is intended to be called before entering
H_CEDE (and it is used by the pseries cpuidle driver). However the
default pseries idle routine does not call it, leading to mismanaged
lazy irq state when the cpuidle driver isn't in use. Manifestations of
this include:

* Dropped IPIs in the time immediately after a cpu comes
  online (before it has installed the cpuidle handler), making the
  online operation block indefinitely waiting for the new cpu to
  respond.

* Hitting this WARN_ON in arch_local_irq_restore():
	/*
	 * We should already be hard disabled here. We had bugs
	 * where that wasn't the case so let's dbl check it and
	 * warn if we are wrong. Only do that when IRQ tracing
	 * is enabled as mfmsr() can be costly.
	 */
	if (WARN_ON_ONCE(mfmsr() & MSR_EE))
		__hard_irq_disable();

Call prep_irq_for_idle() from pseries_lpar_idle() and honor its
result.

Fixes: 363edbe2614a ("powerpc: Default arch idle could cede processor on pseries")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190910225244.25056-1-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/pseries/mobility: use cond_resched when updating device tree 2019-10-07T16:59:10+00:00 Nathan Lynch nathanl@linux.ibm.com 2019-08-02T19:29:26+00:00 4ce5f278af62cd9ebe019439730bc182f2083de9 [ Upstream commit ccfb5bd71d3d1228090a8633800ae7cdf42a94ac ] After a partition migration, pseries_devicetree_update() processes changes to the device tree communicated from the platform to Linux. This is a relatively heavyweight operation, with multiple device tree searches, memory allocations, and conversations with partition firmware. There's a few levels of nested loops which are bounded only by decisions made by the platform, outside of Linux's control, and indeed we have seen RCU stalls on large systems while executing this call graph. Use cond_resched() in these loops so that the cpu is yielded when needed. Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190802192926.19277-4-nathanl@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ccfb5bd71d3d1228090a8633800ae7cdf42a94ac ]

After a partition migration, pseries_devicetree_update() processes
changes to the device tree communicated from the platform to
Linux. This is a relatively heavyweight operation, with multiple
device tree searches, memory allocations, and conversations with
partition firmware.

There's a few levels of nested loops which are bounded only by
decisions made by the platform, outside of Linux's control, and indeed
we have seen RCU stalls on large systems while executing this call
graph. Use cond_resched() in these loops so that the cpu is yielded
when needed.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802192926.19277-4-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/powernv/ioda2: Allocate TCE table levels on demand for default DMA window 2019-10-07T16:58:58+00:00 Alexey Kardashevskiy aik@ozlabs.ru 2019-07-18T05:11:38+00:00 672ce7241a4006d42b8d7a2c946c08a5a34a4428 [ Upstream commit c37c792dec0929dbb6360a609fb00fa20bb16fc2 ] We allocate only the first level of multilevel TCE tables for KVM already (alloc_userspace_copy==true), and the rest is allocated on demand. This is not enabled though for bare metal. This removes the KVM limitation (implicit, via the alloc_userspace_copy parameter) and always allocates just the first level. The on-demand allocation of missing levels is already implemented. As from now on DMA map might happen with disabled interrupts, this allocates TCEs with GFP_ATOMIC; otherwise lockdep reports errors 1]. In practice just a single page is allocated there so chances for failure are quite low. To save time when creating a new clean table, this skips non-allocated indirect TCE entries in pnv_tce_free just like we already do in the VFIO IOMMU TCE driver. This changes the default level number from 1 to 2 to reduce the amount of memory required for the default 32bit DMA window at the boot time. The default window size is up to 2GB which requires 4MB of TCEs which is unlikely to be used entirely or at all as most devices these days are 64bit capable so by switching to 2 levels by default we save 4032KB of RAM per a device. While at this, add __GFP_NOWARN to alloc_pages_node() as the userspace can trigger this path via VFIO, see the failure and try creating a table again with different parameters which might succeed. [1]: === BUG: sleeping function called from invalid context at mm/page_alloc.c:4596 in_atomic(): 1, irqs_disabled(): 1, pid: 1038, name: scsi_eh_1 2 locks held by scsi_eh_1/1038: #0: 000000005efd659a (&host->eh_mutex){+.+.}, at: ata_eh_acquire+0x34/0x80 #1: 0000000006cf56a6 (&(&host->lock)->rlock){....}, at: ata_exec_internal_sg+0xb0/0x5c0 irq event stamp: 500 hardirqs last enabled at (499): [<c000000000cb8a74>] _raw_spin_unlock_irqrestore+0x94/0xd0 hardirqs last disabled at (500): [<c000000000cb85c4>] _raw_spin_lock_irqsave+0x44/0x120 softirqs last enabled at (0): [<c000000000101120>] copy_process.isra.4.part.5+0x640/0x1a80 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 73 PID: 1038 Comm: scsi_eh_1 Not tainted 5.2.0-rc6-le_nv2_aikATfstn1-p1 #634 Call Trace: [c000003d064cef50] [c000000000c8e6c4] dump_stack+0xe8/0x164 (unreliable) [c000003d064cefa0] [c00000000014ed78] ___might_sleep+0x2f8/0x310 [c000003d064cf020] [c0000000003ca084] __alloc_pages_nodemask+0x2a4/0x1560 [c000003d064cf220] [c0000000000c2530] pnv_alloc_tce_level.isra.0+0x90/0x130 [c000003d064cf290] [c0000000000c2888] pnv_tce+0x128/0x3b0 [c000003d064cf360] [c0000000000c2c00] pnv_tce_build+0xb0/0xf0 [c000003d064cf3c0] [c0000000000bbd9c] pnv_ioda2_tce_build+0x3c/0xb0 [c000003d064cf400] [c00000000004cfe0] ppc_iommu_map_sg+0x210/0x550 [c000003d064cf510] [c00000000004b7a4] dma_iommu_map_sg+0x74/0xb0 [c000003d064cf530] [c000000000863944] ata_qc_issue+0x134/0x470 [c000003d064cf5b0] [c000000000863ec4] ata_exec_internal_sg+0x244/0x5c0 [c000003d064cf700] [c0000000008642d0] ata_exec_internal+0x90/0xe0 [c000003d064cf780] [c0000000008650ac] ata_dev_read_id+0x2ec/0x640 [c000003d064cf8d0] [c000000000878e28] ata_eh_recover+0x948/0x16d0 [c000003d064cfa10] [c00000000087d760] sata_pmp_error_handler+0x480/0xbf0 [c000003d064cfbc0] [c000000000884624] ahci_error_handler+0x74/0xe0 [c000003d064cfbf0] [c000000000879fa8] ata_scsi_port_error_handler+0x2d8/0x7c0 [c000003d064cfca0] [c00000000087a544] ata_scsi_error+0xb4/0x100 [c000003d064cfd00] [c000000000802450] scsi_error_handler+0x120/0x510 [c000003d064cfdb0] [c000000000140c48] kthread+0x1b8/0x1c0 [c000003d064cfe20] [c00000000000bd8c] ret_from_kernel_thread+0x5c/0x70 ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300) irq event stamp: 2305 ======================================================== hardirqs last enabled at (2305): [<c00000000000e4c8>] fast_exc_return_irq+0x28/0x34 hardirqs last disabled at (2303): [<c000000000cb9fd0>] __do_softirq+0x4a0/0x654 WARNING: possible irq lock inversion dependency detected 5.2.0-rc6-le_nv2_aikATfstn1-p1 #634 Tainted: G W softirqs last enabled at (2304): [<c000000000cba054>] __do_softirq+0x524/0x654 softirqs last disabled at (2297): [<c00000000010f278>] irq_exit+0x128/0x180 -------------------------------------------------------- swapper/0/0 just changed the state of lock: 0000000006cf56a6 (&(&host->lock)->rlock){-...}, at: ahci_single_level_irq_intr+0xac/0x120 but this lock took another, HARDIRQ-unsafe lock in the past: (fs_reclaim){+.+.} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); local_irq_disable(); lock(&(&host->lock)->rlock); lock(fs_reclaim); <Interrupt> lock(&(&host->lock)->rlock); *** DEADLOCK *** no locks held by swapper/0/0. the shortest dependencies between 2nd lock and 1st lock: -> (fs_reclaim){+.+.} ops: 167579 { HARDIRQ-ON-W at: lock_acquire+0xf8/0x2a0 fs_reclaim_acquire.part.23+0x44/0x60 kmem_cache_alloc_node_trace+0x80/0x590 alloc_desc+0x64/0x270 __irq_alloc_descs+0x2e4/0x3a0 irq_domain_alloc_descs+0xb0/0x150 irq_create_mapping+0x168/0x2c0 xics_smp_probe+0x2c/0x98 pnv_smp_probe+0x40/0x9c smp_prepare_cpus+0x524/0x6c4 kernel_init_freeable+0x1b4/0x650 kernel_init+0x2c/0x148 ret_from_kernel_thread+0x5c/0x70 SOFTIRQ-ON-W at: lock_acquire+0xf8/0x2a0 fs_reclaim_acquire.part.23+0x44/0x60 kmem_cache_alloc_node_trace+0x80/0x590 alloc_desc+0x64/0x270 __irq_alloc_descs+0x2e4/0x3a0 irq_domain_alloc_descs+0xb0/0x150 irq_create_mapping+0x168/0x2c0 xics_smp_probe+0x2c/0x98 pnv_smp_probe+0x40/0x9c smp_prepare_cpus+0x524/0x6c4 kernel_init_freeable+0x1b4/0x650 kernel_init+0x2c/0x148 ret_from_kernel_thread+0x5c/0x70 INITIAL USE at: lock_acquire+0xf8/0x2a0 fs_reclaim_acquire.part.23+0x44/0x60 kmem_cache_alloc_node_trace+0x80/0x590 alloc_desc+0x64/0x270 __irq_alloc_descs+0x2e4/0x3a0 irq_domain_alloc_descs+0xb0/0x150 irq_create_mapping+0x168/0x2c0 xics_smp_probe+0x2c/0x98 pnv_smp_probe+0x40/0x9c smp_prepare_cpus+0x524/0x6c4 kernel_init_freeable+0x1b4/0x650 kernel_init+0x2c/0x148 ret_from_kernel_thread+0x5c/0x70 } === Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190718051139.74787-4-aik@ozlabs.ru Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c37c792dec0929dbb6360a609fb00fa20bb16fc2 ]

We allocate only the first level of multilevel TCE tables for KVM
already (alloc_userspace_copy==true), and the rest is allocated on demand.
This is not enabled though for bare metal.

This removes the KVM limitation (implicit, via the alloc_userspace_copy
parameter) and always allocates just the first level. The on-demand
allocation of missing levels is already implemented.

As from now on DMA map might happen with disabled interrupts, this
allocates TCEs with GFP_ATOMIC; otherwise lockdep reports errors 1].
In practice just a single page is allocated there so chances for failure
are quite low.

To save time when creating a new clean table, this skips non-allocated
indirect TCE entries in pnv_tce_free just like we already do in
the VFIO IOMMU TCE driver.

This changes the default level number from 1 to 2 to reduce the amount
of memory required for the default 32bit DMA window at the boot time.
The default window size is up to 2GB which requires 4MB of TCEs which is
unlikely to be used entirely or at all as most devices these days are
64bit capable so by switching to 2 levels by default we save 4032KB of
RAM per a device.

While at this, add __GFP_NOWARN to alloc_pages_node() as the userspace
can trigger this path via VFIO, see the failure and try creating a table
again with different parameters which might succeed.

[1]:
===
BUG: sleeping function called from invalid context at mm/page_alloc.c:4596
in_atomic(): 1, irqs_disabled(): 1, pid: 1038, name: scsi_eh_1
2 locks held by scsi_eh_1/1038:
 #0: 000000005efd659a (&host->eh_mutex){+.+.}, at: ata_eh_acquire+0x34/0x80
 #1: 0000000006cf56a6 (&(&host->lock)->rlock){....}, at: ata_exec_internal_sg+0xb0/0x5c0
irq event stamp: 500
hardirqs last  enabled at (499): [<c000000000cb8a74>] _raw_spin_unlock_irqrestore+0x94/0xd0
hardirqs last disabled at (500): [<c000000000cb85c4>] _raw_spin_lock_irqsave+0x44/0x120
softirqs last  enabled at (0): [<c000000000101120>] copy_process.isra.4.part.5+0x640/0x1a80
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 73 PID: 1038 Comm: scsi_eh_1 Not tainted 5.2.0-rc6-le_nv2_aikATfstn1-p1 #634
Call Trace:
[c000003d064cef50] [c000000000c8e6c4] dump_stack+0xe8/0x164 (unreliable)
[c000003d064cefa0] [c00000000014ed78] ___might_sleep+0x2f8/0x310
[c000003d064cf020] [c0000000003ca084] __alloc_pages_nodemask+0x2a4/0x1560
[c000003d064cf220] [c0000000000c2530] pnv_alloc_tce_level.isra.0+0x90/0x130
[c000003d064cf290] [c0000000000c2888] pnv_tce+0x128/0x3b0
[c000003d064cf360] [c0000000000c2c00] pnv_tce_build+0xb0/0xf0
[c000003d064cf3c0] [c0000000000bbd9c] pnv_ioda2_tce_build+0x3c/0xb0
[c000003d064cf400] [c00000000004cfe0] ppc_iommu_map_sg+0x210/0x550
[c000003d064cf510] [c00000000004b7a4] dma_iommu_map_sg+0x74/0xb0
[c000003d064cf530] [c000000000863944] ata_qc_issue+0x134/0x470
[c000003d064cf5b0] [c000000000863ec4] ata_exec_internal_sg+0x244/0x5c0
[c000003d064cf700] [c0000000008642d0] ata_exec_internal+0x90/0xe0
[c000003d064cf780] [c0000000008650ac] ata_dev_read_id+0x2ec/0x640
[c000003d064cf8d0] [c000000000878e28] ata_eh_recover+0x948/0x16d0
[c000003d064cfa10] [c00000000087d760] sata_pmp_error_handler+0x480/0xbf0
[c000003d064cfbc0] [c000000000884624] ahci_error_handler+0x74/0xe0
[c000003d064cfbf0] [c000000000879fa8] ata_scsi_port_error_handler+0x2d8/0x7c0
[c000003d064cfca0] [c00000000087a544] ata_scsi_error+0xb4/0x100
[c000003d064cfd00] [c000000000802450] scsi_error_handler+0x120/0x510
[c000003d064cfdb0] [c000000000140c48] kthread+0x1b8/0x1c0
[c000003d064cfe20] [c00000000000bd8c] ret_from_kernel_thread+0x5c/0x70
ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
irq event stamp: 2305

========================================================
hardirqs last  enabled at (2305): [<c00000000000e4c8>] fast_exc_return_irq+0x28/0x34
hardirqs last disabled at (2303): [<c000000000cb9fd0>] __do_softirq+0x4a0/0x654
WARNING: possible irq lock inversion dependency detected
5.2.0-rc6-le_nv2_aikATfstn1-p1 #634 Tainted: G        W
softirqs last  enabled at (2304): [<c000000000cba054>] __do_softirq+0x524/0x654
softirqs last disabled at (2297): [<c00000000010f278>] irq_exit+0x128/0x180
--------------------------------------------------------
swapper/0/0 just changed the state of lock:
0000000006cf56a6 (&(&host->lock)->rlock){-...}, at: ahci_single_level_irq_intr+0xac/0x120
but this lock took another, HARDIRQ-unsafe lock in the past:
 (fs_reclaim){+.+.}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               local_irq_disable();
                               lock(&(&host->lock)->rlock);
                               lock(fs_reclaim);
  <Interrupt>
    lock(&(&host->lock)->rlock);

 *** DEADLOCK ***

no locks held by swapper/0/0.

the shortest dependencies between 2nd lock and 1st lock:
 -> (fs_reclaim){+.+.} ops: 167579 {
    HARDIRQ-ON-W at:
                      lock_acquire+0xf8/0x2a0
                      fs_reclaim_acquire.part.23+0x44/0x60
                      kmem_cache_alloc_node_trace+0x80/0x590
                      alloc_desc+0x64/0x270
                      __irq_alloc_descs+0x2e4/0x3a0
                      irq_domain_alloc_descs+0xb0/0x150
                      irq_create_mapping+0x168/0x2c0
                      xics_smp_probe+0x2c/0x98
                      pnv_smp_probe+0x40/0x9c
                      smp_prepare_cpus+0x524/0x6c4
                      kernel_init_freeable+0x1b4/0x650
                      kernel_init+0x2c/0x148
                      ret_from_kernel_thread+0x5c/0x70
    SOFTIRQ-ON-W at:
                      lock_acquire+0xf8/0x2a0
                      fs_reclaim_acquire.part.23+0x44/0x60
                      kmem_cache_alloc_node_trace+0x80/0x590
                      alloc_desc+0x64/0x270
                      __irq_alloc_descs+0x2e4/0x3a0
                      irq_domain_alloc_descs+0xb0/0x150
                      irq_create_mapping+0x168/0x2c0
                      xics_smp_probe+0x2c/0x98
                      pnv_smp_probe+0x40/0x9c
                      smp_prepare_cpus+0x524/0x6c4
                      kernel_init_freeable+0x1b4/0x650
                      kernel_init+0x2c/0x148
                      ret_from_kernel_thread+0x5c/0x70
    INITIAL USE at:
                     lock_acquire+0xf8/0x2a0
                     fs_reclaim_acquire.part.23+0x44/0x60
                     kmem_cache_alloc_node_trace+0x80/0x590
                     alloc_desc+0x64/0x270
                     __irq_alloc_descs+0x2e4/0x3a0
                     irq_domain_alloc_descs+0xb0/0x150
                     irq_create_mapping+0x168/0x2c0
                     xics_smp_probe+0x2c/0x98
                     pnv_smp_probe+0x40/0x9c
                     smp_prepare_cpus+0x524/0x6c4
                     kernel_init_freeable+0x1b4/0x650
                     kernel_init+0x2c/0x148
                     ret_from_kernel_thread+0x5c/0x70
  }
===

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190718051139.74787-4-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/imc: Dont create debugfs files for cpu-less nodes 2019-10-05T11:14:03+00:00 Madhavan Srinivasan maddy@linux.vnet.ibm.com 2019-08-27T10:16:35+00:00 830afcbc9391796a2c49a3fa9ef42e1691cc21be commit 41ba17f20ea835c489e77bd54e2da73184e22060 upstream. Commit <684d984038aa> ('powerpc/powernv: Add debugfs interface for imc-mode and imc') added debugfs interface for the nest imc pmu devices to support changing of different ucode modes. Primarily adding this capability for debug. But when doing so, the code did not consider the case of cpu-less nodes. So when reading the _cmd_ or _mode_ file of a cpu-less node will create this crash. Faulting instruction address: 0xc0000000000d0d58 Oops: Kernel access of bad area, sig: 11 [#1] ... CPU: 67 PID: 5301 Comm: cat Not tainted 5.2.0-rc6-next-20190627+ #19 NIP: c0000000000d0d58 LR: c00000000049aa18 CTR:c0000000000d0d50 REGS: c00020194548f9e0 TRAP: 0300 Not tainted (5.2.0-rc6-next-20190627+) MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR:28022822 XER: 00000000 CFAR: c00000000049aa14 DAR: 000000000003fc08 DSISR:40000000 IRQMASK: 0 ... NIP imc_mem_get+0x8/0x20 LR simple_attr_read+0x118/0x170 Call Trace: simple_attr_read+0x70/0x170 (unreliable) debugfs_attr_read+0x6c/0xb0 __vfs_read+0x3c/0x70 vfs_read+0xbc/0x1a0 ksys_read+0x7c/0x140 system_call+0x5c/0x70 Patch fixes the issue with a more robust check for vbase to NULL. Before patch, ls output for the debugfs imc directory # ls /sys/kernel/debug/powerpc/imc/ imc_cmd_0 imc_cmd_251 imc_cmd_253 imc_cmd_255 imc_mode_0 imc_mode_251 imc_mode_253 imc_mode_255 imc_cmd_250 imc_cmd_252 imc_cmd_254 imc_cmd_8 imc_mode_250 imc_mode_252 imc_mode_254 imc_mode_8 After patch, ls output for the debugfs imc directory # ls /sys/kernel/debug/powerpc/imc/ imc_cmd_0 imc_cmd_8 imc_mode_0 imc_mode_8 Actual bug here is that, we have two loops with potentially different loop counts. That is, in imc_get_mem_addr_nest(), loop count is obtained from the dt entries. But in case of export_imc_mode_and_cmd(), loop was based on for_each_nid() count. Patch fixes the loop count in latter based on the struct mem_info. Ideally it would be better to have array size in struct imc_pmu. Fixes: 684d984038aa ('powerpc/powernv: Add debugfs interface for imc-mode and imc') Reported-by: Qian Cai <cai@lca.pw> Suggested-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190827101635.6942-1-maddy@linux.vnet.ibm.com Cc: Jan Stancek <jstancek@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 41ba17f20ea835c489e77bd54e2da73184e22060 upstream.

Commit <684d984038aa> ('powerpc/powernv: Add debugfs interface for
imc-mode and imc') added debugfs interface for the nest imc pmu
devices to support changing of different ucode modes. Primarily adding
this capability for debug. But when doing so, the code did not
consider the case of cpu-less nodes. So when reading the _cmd_ or
_mode_ file of a cpu-less node will create this crash.

  Faulting instruction address: 0xc0000000000d0d58
  Oops: Kernel access of bad area, sig: 11 [#1]
  ...
  CPU: 67 PID: 5301 Comm: cat Not tainted 5.2.0-rc6-next-20190627+ #19
  NIP:  c0000000000d0d58 LR: c00000000049aa18 CTR:c0000000000d0d50
  REGS: c00020194548f9e0 TRAP: 0300   Not tainted  (5.2.0-rc6-next-20190627+)
  MSR:  9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR:28022822  XER: 00000000
  CFAR: c00000000049aa14 DAR: 000000000003fc08 DSISR:40000000 IRQMASK: 0
  ...
  NIP imc_mem_get+0x8/0x20
  LR  simple_attr_read+0x118/0x170
  Call Trace:
    simple_attr_read+0x70/0x170 (unreliable)
    debugfs_attr_read+0x6c/0xb0
    __vfs_read+0x3c/0x70
     vfs_read+0xbc/0x1a0
    ksys_read+0x7c/0x140
    system_call+0x5c/0x70

Patch fixes the issue with a more robust check for vbase to NULL.

Before patch, ls output for the debugfs imc directory

  # ls /sys/kernel/debug/powerpc/imc/
  imc_cmd_0    imc_cmd_251  imc_cmd_253  imc_cmd_255  imc_mode_0    imc_mode_251  imc_mode_253  imc_mode_255
  imc_cmd_250  imc_cmd_252  imc_cmd_254  imc_cmd_8    imc_mode_250  imc_mode_252  imc_mode_254  imc_mode_8

After patch, ls output for the debugfs imc directory

  # ls /sys/kernel/debug/powerpc/imc/
  imc_cmd_0  imc_cmd_8  imc_mode_0  imc_mode_8

Actual bug here is that, we have two loops with potentially different
loop counts. That is, in imc_get_mem_addr_nest(), loop count is
obtained from the dt entries. But in case of export_imc_mode_and_cmd(),
loop was based on for_each_nid() count. Patch fixes the loop count in
latter based on the struct mem_info. Ideally it would be better to
have array size in struct imc_pmu.

Fixes: 684d984038aa ('powerpc/powernv: Add debugfs interface for imc-mode and imc')
Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190827101635.6942-1-maddy@linux.vnet.ibm.com
Cc: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
powerpc/xive: Fix bogus error code returned by OPAL 2019-10-01T07:01:36+00:00 Greg Kurz groug@kaod.org 2019-09-11T15:52:18+00:00 be3b5f44206e05c06702de30e0d0565377e0eb40 commit 6ccb4ac2bf8a35c694ead92f8ac5530a16e8f2c8 upstream. There's a bug in skiboot that causes the OPAL_XIVE_ALLOCATE_IRQ call to return the 32-bit value 0xffffffff when OPAL has run out of IRQs. Unfortunatelty, OPAL return values are signed 64-bit entities and errors are supposed to be negative. If that happens, the linux code confusingly treats 0xffffffff as a valid IRQ number and panics at some point. A fix was recently merged in skiboot: e97391ae2bb5 ("xive: fix return value of opal_xive_allocate_irq()") but we need a workaround anyway to support older skiboots already in the field. Internally convert 0xffffffff to OPAL_RESOURCE which is the usual error returned upon resource exhaustion. Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/156821713818.1985334.14123187368108582810.stgit@bahia.lan Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6ccb4ac2bf8a35c694ead92f8ac5530a16e8f2c8 upstream.

There's a bug in skiboot that causes the OPAL_XIVE_ALLOCATE_IRQ call
to return the 32-bit value 0xffffffff when OPAL has run out of IRQs.
Unfortunatelty, OPAL return values are signed 64-bit entities and
errors are supposed to be negative. If that happens, the linux code
confusingly treats 0xffffffff as a valid IRQ number and panics at some
point.

A fix was recently merged in skiboot:

e97391ae2bb5 ("xive: fix return value of opal_xive_allocate_irq()")

but we need a workaround anyway to support older skiboots already
in the field.

Internally convert 0xffffffff to OPAL_RESOURCE which is the usual error
returned upon resource exhaustion.

Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821713818.1985334.14123187368108582810.stgit@bahia.lan
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
powerpc/nvdimm: Pick nearby online node if the device node is not online 2019-08-25T14:10:29+00:00 Aneesh Kumar K.V aneesh.kumar@linux.ibm.com 2019-07-29T09:51:28+00:00 c5afac52e87e4759467e6bb0e196f809da58fd17 [ Upstream commit da1115fdbd6e86c62185cdd2b4bf7add39f2f82b ] Currently, nvdimm subsystem expects the device numa node for SCM device to be an online node. It also doesn't try to bring the device numa node online. Hence if we use a non-online numa node as device node we hit crashes like below. This is because we try to access uninitialized NODE_DATA in different code paths. cpu 0x0: Vector: 300 (Data Access) at [c0000000fac53170] pc: c0000000004bbc50: ___slab_alloc+0x120/0xca0 lr: c0000000004bc834: __slab_alloc+0x64/0xc0 sp: c0000000fac53400 msr: 8000000002009033 dar: 73e8 dsisr: 80000 current = 0xc0000000fabb6d80 paca = 0xc000000003870000 irqmask: 0x03 irq_happened: 0x01 pid = 7, comm = kworker/u16:0 Linux version 5.2.0-06234-g76bd729b2644 (kvaneesh@ltc-boston123) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #135 SMP Thu Jul 11 05:36:30 CDT 2019 enter ? for help [link register ] c0000000004bc834 __slab_alloc+0x64/0xc0 [c0000000fac53400] c0000000fac53480 (unreliable) [c0000000fac53500] c0000000004bc818 __slab_alloc+0x48/0xc0 [c0000000fac53560] c0000000004c30a0 __kmalloc_node_track_caller+0x3c0/0x6b0 [c0000000fac535d0] c000000000cfafe4 devm_kmalloc+0x74/0xc0 [c0000000fac53600] c000000000d69434 nd_region_activate+0x144/0x560 [c0000000fac536d0] c000000000d6b19c nd_region_probe+0x17c/0x370 [c0000000fac537b0] c000000000d6349c nvdimm_bus_probe+0x10c/0x230 [c0000000fac53840] c000000000cf3cc4 really_probe+0x254/0x4e0 [c0000000fac538d0] c000000000cf429c driver_probe_device+0x16c/0x1e0 [c0000000fac53950] c000000000cf0b44 bus_for_each_drv+0x94/0x130 [c0000000fac539b0] c000000000cf392c __device_attach+0xdc/0x200 [c0000000fac53a50] c000000000cf231c bus_probe_device+0x4c/0xf0 [c0000000fac53a90] c000000000ced268 device_add+0x528/0x810 [c0000000fac53b60] c000000000d62a58 nd_async_device_register+0x28/0xa0 [c0000000fac53bd0] c0000000001ccb8c async_run_entry_fn+0xcc/0x1f0 [c0000000fac53c50] c0000000001bcd9c process_one_work+0x46c/0x860 [c0000000fac53d20] c0000000001bd4f4 worker_thread+0x364/0x5f0 [c0000000fac53db0] c0000000001c7260 kthread+0x1b0/0x1c0 [c0000000fac53e20] c00000000000b954 ret_from_kernel_thread+0x5c/0x68 The patch tries to fix this by picking the nearest online node as the SCM node. This does have a problem of us losing the information that SCM node is equidistant from two other online nodes. If applications need to understand these fine-grained details we should express then like x86 does via /sys/devices/system/node/nodeX/accessY/initiators/ With the patch we get # numactl -H available: 2 nodes (0-1) node 0 cpus: node 0 size: 0 MB node 0 free: 0 MB node 1 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 node 1 size: 130865 MB node 1 free: 129130 MB node distances: node 0 1 0: 10 20 1: 20 10 # cat /sys/bus/nd/devices/region0/numa_node 0 # dmesg | grep papr_scm [ 91.332305] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Region registered with target node 2 and online node 0 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190729095128.23707-1-aneesh.kumar@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit da1115fdbd6e86c62185cdd2b4bf7add39f2f82b ]

Currently, nvdimm subsystem expects the device numa node for SCM device to be
an online node. It also doesn't try to bring the device numa node online. Hence
if we use a non-online numa node as device node we hit crashes like below. This
is because we try to access uninitialized NODE_DATA in different code paths.

cpu 0x0: Vector: 300 (Data Access) at [c0000000fac53170]
    pc: c0000000004bbc50: ___slab_alloc+0x120/0xca0
    lr: c0000000004bc834: __slab_alloc+0x64/0xc0
    sp: c0000000fac53400
   msr: 8000000002009033
   dar: 73e8
 dsisr: 80000
  current = 0xc0000000fabb6d80
  paca    = 0xc000000003870000   irqmask: 0x03   irq_happened: 0x01
    pid   = 7, comm = kworker/u16:0
Linux version 5.2.0-06234-g76bd729b2644 (kvaneesh@ltc-boston123) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #135 SMP Thu Jul 11 05:36:30 CDT 2019
enter ? for help
[link register   ] c0000000004bc834 __slab_alloc+0x64/0xc0
[c0000000fac53400] c0000000fac53480 (unreliable)
[c0000000fac53500] c0000000004bc818 __slab_alloc+0x48/0xc0
[c0000000fac53560] c0000000004c30a0 __kmalloc_node_track_caller+0x3c0/0x6b0
[c0000000fac535d0] c000000000cfafe4 devm_kmalloc+0x74/0xc0
[c0000000fac53600] c000000000d69434 nd_region_activate+0x144/0x560
[c0000000fac536d0] c000000000d6b19c nd_region_probe+0x17c/0x370
[c0000000fac537b0] c000000000d6349c nvdimm_bus_probe+0x10c/0x230
[c0000000fac53840] c000000000cf3cc4 really_probe+0x254/0x4e0
[c0000000fac538d0] c000000000cf429c driver_probe_device+0x16c/0x1e0
[c0000000fac53950] c000000000cf0b44 bus_for_each_drv+0x94/0x130
[c0000000fac539b0] c000000000cf392c __device_attach+0xdc/0x200
[c0000000fac53a50] c000000000cf231c bus_probe_device+0x4c/0xf0
[c0000000fac53a90] c000000000ced268 device_add+0x528/0x810
[c0000000fac53b60] c000000000d62a58 nd_async_device_register+0x28/0xa0
[c0000000fac53bd0] c0000000001ccb8c async_run_entry_fn+0xcc/0x1f0
[c0000000fac53c50] c0000000001bcd9c process_one_work+0x46c/0x860
[c0000000fac53d20] c0000000001bd4f4 worker_thread+0x364/0x5f0
[c0000000fac53db0] c0000000001c7260 kthread+0x1b0/0x1c0
[c0000000fac53e20] c00000000000b954 ret_from_kernel_thread+0x5c/0x68

The patch tries to fix this by picking the nearest online node as the SCM node.
This does have a problem of us losing the information that SCM node is
equidistant from two other online nodes. If applications need to understand these
fine-grained details we should express then like x86 does via
/sys/devices/system/node/nodeX/accessY/initiators/

With the patch we get

 # numactl -H
available: 2 nodes (0-1)
node 0 cpus:
node 0 size: 0 MB
node 0 free: 0 MB
node 1 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
node 1 size: 130865 MB
node 1 free: 129130 MB
node distances:
node   0   1
  0:  10  20
  1:  20  10
 # cat /sys/bus/nd/devices/region0/numa_node
0
 # dmesg | grep papr_scm
[   91.332305] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Region registered with target node 2 and online node 0

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190729095128.23707-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/papr_scm: Force a scm-unbind if initial scm-bind fails 2019-08-16T08:11:03+00:00 Vaibhav Jain vaibhav@linux.ibm.com 2019-06-29T16:06:10+00:00 8a6709ad4ceff3a4aba8f09a45505e9afbfdb04c [ Upstream commit 3a855b7ac7d5021674aa3e1cc9d3bfd6b604e9c0 ] In some cases initial bind of scm memory for an lpar can fail if previously it wasn't released using a scm-unbind hcall. This situation can arise due to panic of the previous kernel or forced lpar fadump. In such cases the H_SCM_BIND_MEM return a H_OVERLAP error. To mitigate such cases the patch updates papr_scm_probe() to force a call to drc_pmem_unbind() in case the initial bind of scm memory fails with EBUSY error. In case scm-bind operation again fails after the forced scm-unbind then we follow the existing error path. We also update drc_pmem_bind() to handle the H_OVERLAP error returned by phyp and indicate it as a EBUSY error back to the caller. Suggested-by: "Oliver O'Halloran" <oohall@gmail.com> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com> Reviewed-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190629160610.23402-4-vaibhav@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3a855b7ac7d5021674aa3e1cc9d3bfd6b604e9c0 ]

In some cases initial bind of scm memory for an lpar can fail if
previously it wasn't released using a scm-unbind hcall. This situation
can arise due to panic of the previous kernel or forced lpar
fadump. In such cases the H_SCM_BIND_MEM return a H_OVERLAP error.

To mitigate such cases the patch updates papr_scm_probe() to force a
call to drc_pmem_unbind() in case the initial bind of scm memory fails
with EBUSY error. In case scm-bind operation again fails after the
forced scm-unbind then we follow the existing error path. We also
update drc_pmem_bind() to handle the H_OVERLAP error returned by phyp
and indicate it as a EBUSY error back to the caller.

Suggested-by: "Oliver O'Halloran" <oohall@gmail.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190629160610.23402-4-vaibhav@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/4xx/uic: clear pending interrupt after irq type/pol change 2019-07-31T05:24:46+00:00 Christian Lamparter chunkeey@gmail.com 2019-06-15T15:23:13+00:00 d97cfca8faa49344252174c2e3194cc45496e170 [ Upstream commit 3ab3a0689e74e6aa5b41360bc18861040ddef5b1 ] When testing out gpio-keys with a button, a spurious interrupt (and therefore a key press or release event) gets triggered as soon as the driver enables the irq line for the first time. This patch clears any potential bogus generated interrupt that was caused by the switching of the associated irq's type and polarity. Signed-off-by: Christian Lamparter <chunkeey@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3ab3a0689e74e6aa5b41360bc18861040ddef5b1 ]

When testing out gpio-keys with a button, a spurious
interrupt (and therefore a key press or release event)
gets triggered as soon as the driver enables the irq
line for the first time.

This patch clears any potential bogus generated interrupt
that was caused by the switching of the associated irq's
type and polarity.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/pseries/mobility: prevent cpu hotplug during DT update 2019-07-31T05:24:40+00:00 Nathan Lynch nathanl@linux.ibm.com 2019-06-12T04:45:05+00:00 e26242e226785f6148689673ec281f89b0bf2931 [ Upstream commit e59a175faa8df9d674247946f2a5a9c29c835725 ] CPU online/offline code paths are sensitive to parts of the device tree (various cpu node properties, cache nodes) that can be changed as a result of a migration. Prevent CPU hotplug while the device tree potentially is inconsistent. Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel") Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e59a175faa8df9d674247946f2a5a9c29c835725 ]

CPU online/offline code paths are sensitive to parts of the device
tree (various cpu node properties, cache nodes) that can be changed as
a result of a migration.

Prevent CPU hotplug while the device tree potentially is inconsistent.

Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc/pseries: Fix oops in hotplug memory notifier 2019-07-26T07:11:09+00:00 Nathan Lynch nathanl@linux.ibm.com 2019-06-07T05:04:07+00:00 a63f2ef2082312a7678187296e67d2cb1273ad63 commit 0aa82c482ab2ece530a6f44897b63b274bb43c8e upstream. During post-migration device tree updates, we can oops in pseries_update_drconf_memory() if the source device tree has an ibm,dynamic-memory-v2 property and the destination has a ibm,dynamic_memory (v1) property. The notifier processes an "update" for the ibm,dynamic-memory property but it's really an add in this scenario. So make sure the old property object is there before dereferencing it. Fixes: 2b31e3aec1db ("powerpc/drmem: Add support for ibm, dynamic-memory-v2 property") Cc: stable@vger.kernel.org # v4.16+ Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0aa82c482ab2ece530a6f44897b63b274bb43c8e upstream.

During post-migration device tree updates, we can oops in
pseries_update_drconf_memory() if the source device tree has an
ibm,dynamic-memory-v2 property and the destination has a
ibm,dynamic_memory (v1) property. The notifier processes an "update"
for the ibm,dynamic-memory property but it's really an add in this
scenario. So make sure the old property object is there before
dereferencing it.

Fixes: 2b31e3aec1db ("powerpc/drmem: Add support for ibm, dynamic-memory-v2 property")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>