[PATCH AUTOSEL 4.19 11/50] PCI: rpaphp: Avoid a sometimes-uninitialized warning

[PATCH AUTOSEL 4.19 11/50] PCI: rpaphp: Avoid a sometimes-uninitialized warning

[Sasha Levin]

From: Nathan Chancellor <natechancellor@gmail.com>

[ Upstream commit 0df3e42167caaf9f8c7b64de3da40a459979afe8 ]

When building with -Wsometimes-uninitialized, clang warns:

drivers/pci/hotplug/rpaphp_core.c:243:14: warning: variable 'fndit' is
used uninitialized whenever 'for' loop exits because its condition is
false [-Wsometimes-uninitialized]
        for (j = 0; j < entries; j++) {
                    ^~~~~~~~~~~
drivers/pci/hotplug/rpaphp_core.c:256:6: note: uninitialized use occurs
here
        if (fndit)
            ^~~~~
drivers/pci/hotplug/rpaphp_core.c:243:14: note: remove the condition if
it is always true
        for (j = 0; j < entries; j++) {
                    ^~~~~~~~~~~
drivers/pci/hotplug/rpaphp_core.c:233:14: note: initialize the variable
'fndit' to silence this warning
        int j, fndit;
                    ^
                     = 0

fndit is only used to gate a sprintf call, which can be moved into the
loop to simplify the code and eliminate the local variable, which will
fix this warning.

Fixes: 2fcf3ae508c2 ("hotplug/drc-info: Add code to search ibm,drc-info property")
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Acked-by: Joel Savitz <jsavitz@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://github.com/ClangBuiltLinux/linux/issues/504
Link: https://lore.kernel.org/r/20190603221157.58502-1-natechancellor@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/hotplug/rpaphp_core.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
index 857c358b727b8..cc860c5f7d26f 100644
--- a/drivers/pci/hotplug/rpaphp_core.c
+++ b/drivers/pci/hotplug/rpaphp_core.c
@@ -230,7 +230,7 @@ static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
 	struct of_drc_info drc;
 	const __be32 *value;
 	char cell_drc_name[MAX_DRC_NAME_LEN];
-	int j, fndit;
+	int j;
 
 	info = of_find_property(dn->parent, "ibm,drc-info", NULL);
 	if (info == NULL)
@@ -245,17 +245,13 @@ static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
 
 		/* Should now know end of current entry */
 
-		if (my_index > drc.last_drc_index)
-			continue;
-
-		fndit = 1;
-		break;
+		/* Found it */
+		if (my_index <= drc.last_drc_index) {
+			sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix,
+				my_index);
+			break;
+		}
 	}
-	/* Found it */
-
-	if (fndit)
-		sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix, 
-			my_index);
 
 	if (((drc_name == NULL) ||
 	     (drc_name && !strcmp(drc_name, cell_drc_name))) &&
-- 
2.20.1

[PATCH AUTOSEL 4.19 17/50] powerpc/powernv/ioda2: Allocate TCE table levels on demand for default DMA window

[Sasha Levin]

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ 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>
---
 arch/powerpc/platforms/powernv/pci-ioda-tce.c | 20 +++++++++----------
 arch/powerpc/platforms/powernv/pci.h          |  2 +-
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda-tce.c b/arch/powerpc/platforms/powernv/pci-ioda-tce.c
index f5adb6b756f75..29e66d6e57636 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda-tce.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda-tce.c
@@ -36,7 +36,8 @@ static __be64 *pnv_alloc_tce_level(int nid, unsigned int shift)
 	struct page *tce_mem = NULL;
 	__be64 *addr;
 
-	tce_mem = alloc_pages_node(nid, GFP_KERNEL, shift - PAGE_SHIFT);
+	tce_mem = alloc_pages_node(nid, GFP_ATOMIC | __GFP_NOWARN,
+			shift - PAGE_SHIFT);
 	if (!tce_mem) {
 		pr_err("Failed to allocate a TCE memory, level shift=%d\n",
 				shift);
@@ -161,6 +162,9 @@ void pnv_tce_free(struct iommu_table *tbl, long index, long npages)
 
 		if (ptce)
 			*ptce = cpu_to_be64(0);
+		else
+			/* Skip the rest of the level */
+			i |= tbl->it_level_size - 1;
 	}
 }
 
@@ -260,7 +264,6 @@ long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset,
 	unsigned int table_shift = max_t(unsigned int, entries_shift + 3,
 			PAGE_SHIFT);
 	const unsigned long tce_table_size = 1UL << table_shift;
-	unsigned int tmplevels = levels;
 
 	if (!levels || (levels > POWERNV_IOMMU_MAX_LEVELS))
 		return -EINVAL;
@@ -268,9 +271,6 @@ long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset,
 	if (!is_power_of_2(window_size))
 		return -EINVAL;
 
-	if (alloc_userspace_copy && (window_size > (1ULL << 32)))
-		tmplevels = 1;
-
 	/* Adjust direct table size from window_size and levels */
 	entries_shift = (entries_shift + levels - 1) / levels;
 	level_shift = entries_shift + 3;
@@ -281,7 +281,7 @@ long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset,
 
 	/* Allocate TCE table */
 	addr = pnv_pci_ioda2_table_do_alloc_pages(nid, level_shift,
-			tmplevels, tce_table_size, &offset, &total_allocated);
+			1, tce_table_size, &offset, &total_allocated);
 
 	/* addr==NULL means that the first level allocation failed */
 	if (!addr)
@@ -292,18 +292,18 @@ long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset,
 	 * we did not allocate as much as we wanted,
 	 * release partially allocated table.
 	 */
-	if (tmplevels == levels && offset < tce_table_size)
+	if (levels == 1 && offset < tce_table_size)
 		goto free_tces_exit;
 
 	/* Allocate userspace view of the TCE table */
 	if (alloc_userspace_copy) {
 		offset = 0;
 		uas = pnv_pci_ioda2_table_do_alloc_pages(nid, level_shift,
-				tmplevels, tce_table_size, &offset,
+				1, tce_table_size, &offset,
 				&total_allocated_uas);
 		if (!uas)
 			goto free_tces_exit;
-		if (tmplevels == levels && (offset < tce_table_size ||
+		if (levels == 1 && (offset < tce_table_size ||
 				total_allocated_uas != total_allocated))
 			goto free_uas_exit;
 	}
@@ -318,7 +318,7 @@ long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset,
 
 	pr_debug("Created TCE table: ws=%08llx ts=%lx @%08llx base=%lx uas=%p levels=%d/%d\n",
 			window_size, tce_table_size, bus_offset, tbl->it_base,
-			tbl->it_userspace, tmplevels, levels);
+			tbl->it_userspace, 1, levels);
 
 	return 0;
 
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 8b37b28e38318..e302aa092d4f1 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -243,7 +243,7 @@ extern void pnv_npu_release_ownership(struct pnv_ioda_pe *npe);
 extern int pnv_npu2_init(struct pnv_phb *phb);
 
 /* pci-ioda-tce.c */
-#define POWERNV_IOMMU_DEFAULT_LEVELS	1
+#define POWERNV_IOMMU_DEFAULT_LEVELS	2
 #define POWERNV_IOMMU_MAX_LEVELS	5
 
 extern int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
-- 
2.20.1

[PATCH AUTOSEL 4.19 23/50] powerpc/xmon: Check for HV mode when dumping XIVE info from OPAL

[Sasha Levin]

From: Cédric Le Goater <clg@kaod.org>

[ Upstream commit c3e0dbd7f780a58c4695f1cd8fc8afde80376737 ]

Currently, the xmon 'dx' command calls OPAL to dump the XIVE state in
the OPAL logs and also outputs some of the fields of the internal XIVE
structures in Linux. The OPAL calls can only be done on baremetal
(PowerNV) and they crash a pseries machine. Fix by checking the
hypervisor feature of the CPU.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190814154754.23682-2-clg@kaod.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/xmon/xmon.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 74cfc1be04d6e..bb5db7bfd8539 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -2497,13 +2497,16 @@ static void dump_pacas(void)
 static void dump_one_xive(int cpu)
 {
 	unsigned int hwid = get_hard_smp_processor_id(cpu);
+	bool hv = cpu_has_feature(CPU_FTR_HVMODE);
 
-	opal_xive_dump(XIVE_DUMP_TM_HYP, hwid);
-	opal_xive_dump(XIVE_DUMP_TM_POOL, hwid);
-	opal_xive_dump(XIVE_DUMP_TM_OS, hwid);
-	opal_xive_dump(XIVE_DUMP_TM_USER, hwid);
-	opal_xive_dump(XIVE_DUMP_VP, hwid);
-	opal_xive_dump(XIVE_DUMP_EMU_STATE, hwid);
+	if (hv) {
+		opal_xive_dump(XIVE_DUMP_TM_HYP, hwid);
+		opal_xive_dump(XIVE_DUMP_TM_POOL, hwid);
+		opal_xive_dump(XIVE_DUMP_TM_OS, hwid);
+		opal_xive_dump(XIVE_DUMP_TM_USER, hwid);
+		opal_xive_dump(XIVE_DUMP_VP, hwid);
+		opal_xive_dump(XIVE_DUMP_EMU_STATE, hwid);
+	}
 
 	if (setjmp(bus_error_jmp) != 0) {
 		catch_memory_errors = 0;
-- 
2.20.1

[PATCH AUTOSEL 4.19 24/50] powerpc/rtas: use device model APIs and serialization during LPM

[Sasha Levin]

From: Nathan Lynch <nathanl@linux.ibm.com>

[ Upstream commit a6717c01ddc259f6f73364779df058e2c67309f8 ]

The LPAR migration implementation and userspace-initiated cpu hotplug
can interleave their executions like so:

1. Set cpu 7 offline via sysfs.

2. Begin a partition migration, whose implementation requires the OS
   to ensure all present cpus are online; cpu 7 is onlined:

     rtas_ibm_suspend_me -> rtas_online_cpus_mask -> cpu_up

   This sets cpu 7 online in all respects except for the cpu's
   corresponding struct device; dev->offline remains true.

3. Set cpu 7 online via sysfs. _cpu_up() determines that cpu 7 is
   already online and returns success. The driver core (device_online)
   sets dev->offline = false.

4. The migration completes and restores cpu 7 to offline state:

     rtas_ibm_suspend_me -> rtas_offline_cpus_mask -> cpu_down

This leaves cpu7 in a state where the driver core considers the cpu
device online, but in all other respects it is offline and
unused. Attempts to online the cpu via sysfs appear to succeed but the
driver core actually does not pass the request to the lower-level
cpuhp support code. This makes the cpu unusable until the cpu device
is manually set offline and then online again via sysfs.

Instead of directly calling cpu_up/cpu_down, the migration code should
use the higher-level device core APIs to maintain consistent state and
serialize operations.

Fixes: 120496ac2d2d ("powerpc: Bring all threads online prior to migration/hibernation")
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>
Link: https://lore.kernel.org/r/20190802192926.19277-2-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/rtas.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 8afd146bc9c70..9e41a9de43235 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -875,15 +875,17 @@ static int rtas_cpu_state_change_mask(enum rtas_cpu_state state,
 		return 0;
 
 	for_each_cpu(cpu, cpus) {
+		struct device *dev = get_cpu_device(cpu);
+
 		switch (state) {
 		case DOWN:
-			cpuret = cpu_down(cpu);
+			cpuret = device_offline(dev);
 			break;
 		case UP:
-			cpuret = cpu_up(cpu);
+			cpuret = device_online(dev);
 			break;
 		}
-		if (cpuret) {
+		if (cpuret < 0) {
 			pr_debug("%s: cpu_%s for cpu#%d returned %d.\n",
 					__func__,
 					((state == UP) ? "up" : "down"),
@@ -972,6 +974,8 @@ int rtas_ibm_suspend_me(u64 handle)
 	data.token = rtas_token("ibm,suspend-me");
 	data.complete = &done;
 
+	lock_device_hotplug();
+
 	/* All present CPUs must be online */
 	cpumask_andnot(offline_mask, cpu_present_mask, cpu_online_mask);
 	cpuret = rtas_online_cpus_mask(offline_mask);
@@ -1003,6 +1007,7 @@ int rtas_ibm_suspend_me(u64 handle)
 				__func__);
 
 out:
+	unlock_device_hotplug();
 	free_cpumask_var(offline_mask);
 	return atomic_read(&data.error);
 }
-- 
2.20.1

[PATCH AUTOSEL 4.19 25/50] powerpc/futex: Fix warning: 'oldval' may be used uninitialized in this function

[Sasha Levin]

From: Christophe Leroy <christophe.leroy@c-s.fr>

[ Upstream commit 38a0d0cdb46d3f91534e5b9839ec2d67be14c59d ]

We see warnings such as:
  kernel/futex.c: In function 'do_futex':
  kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized]
     return oldval == cmparg;
                   ^
  kernel/futex.c:1651:6: note: 'oldval' was declared here
    int oldval, ret;
        ^

This is because arch_futex_atomic_op_inuser() only sets *oval if ret
is 0 and GCC doesn't see that it will only use it when ret is 0.

Anyway, the non-zero ret path is an error path that won't suffer from
setting *oval, and as *oval is a local var in futex_atomic_op_inuser()
it will have no impact.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: reword change log slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/86b72f0c134367b214910b27b9a6dd3321af93bb.1565774657.git.christophe.leroy@c-s.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/include/asm/futex.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/futex.h b/arch/powerpc/include/asm/futex.h
index 94542776a62d6..2a7b01f97a56b 100644
--- a/arch/powerpc/include/asm/futex.h
+++ b/arch/powerpc/include/asm/futex.h
@@ -59,8 +59,7 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
 
 	pagefault_enable();
 
-	if (!ret)
-		*oval = oldval;
+	*oval = oldval;
 
 	return ret;
 }
-- 
2.20.1

[PATCH AUTOSEL 4.19 26/50] powerpc/64s/radix: Remove redundant pfn_pte bitop, add VM_BUG_ON

[Sasha Levin]

From: Nicholas Piggin <npiggin@gmail.com>

[ Upstream commit 6bb25170d7a44ef0ed9677814600f0785e7421d1 ]

pfn_pte is never given a pte above the addressable physical memory
limit, so the masking is redundant. In case of a software bug, it
is not obviously better to silently truncate the pfn than to corrupt
the pte (either one will result in memory corruption or crashes),
so there is no reason to add this to the fast path.

Add VM_BUG_ON to catch cases where the pfn is invalid. These would
catch the create_section_mapping bug fixed by a previous commit.

  [16885.256466] ------------[ cut here ]------------
  [16885.256492] kernel BUG at arch/powerpc/include/asm/book3s/64/pgtable.h:612!
  cpu 0x0: Vector: 700 (Program Check) at [c0000000ee0a36d0]
      pc: c000000000080738: __map_kernel_page+0x248/0x6f0
      lr: c000000000080ac0: __map_kernel_page+0x5d0/0x6f0
      sp: c0000000ee0a3960
     msr: 9000000000029033
    current = 0xc0000000ec63b400
    paca    = 0xc0000000017f0000   irqmask: 0x03   irq_happened: 0x01
      pid   = 85, comm = sh
  kernel BUG at arch/powerpc/include/asm/book3s/64/pgtable.h:612!
  Linux version 5.3.0-rc1-00001-g0fe93e5f3394
  enter ? for help
  [c0000000ee0a3a00] c000000000d37378 create_physical_mapping+0x260/0x360
  [c0000000ee0a3b10] c000000000d370bc create_section_mapping+0x1c/0x3c
  [c0000000ee0a3b30] c000000000071f54 arch_add_memory+0x74/0x130

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-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/20190724084638.24982-5-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 855dbae6d351d..a717640b7eda4 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -629,8 +629,10 @@ static inline bool pte_access_permitted(pte_t pte, bool write)
  */
 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 {
-	return __pte((((pte_basic_t)(pfn) << PAGE_SHIFT) & PTE_RPN_MASK) |
-		     pgprot_val(pgprot));
+	VM_BUG_ON(pfn >> (64 - PAGE_SHIFT));
+	VM_BUG_ON((pfn << PAGE_SHIFT) & ~PTE_RPN_MASK);
+
+	return __pte(((pte_basic_t)pfn << PAGE_SHIFT) | pgprot_val(pgprot));
 }
 
 static inline unsigned long pte_pfn(pte_t pte)
-- 
2.20.1

[PATCH AUTOSEL 4.19 27/50] powerpc/pseries/mobility: use cond_resched when updating device tree

[Sasha Levin]

From: Nathan Lynch <nathanl@linux.ibm.com>

[ 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>
---
 arch/powerpc/platforms/pseries/mobility.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 7b60fcf04dc47..e4ea713833832 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -12,6 +12,7 @@
 #include <linux/cpu.h>
 #include <linux/kernel.h>
 #include <linux/kobject.h>
+#include <linux/sched.h>
 #include <linux/smp.h>
 #include <linux/stat.h>
 #include <linux/completion.h>
@@ -209,7 +210,11 @@ static int update_dt_node(__be32 phandle, s32 scope)
 
 				prop_data += vd;
 			}
+
+			cond_resched();
 		}
+
+		cond_resched();
 	} while (rtas_rc == 1);
 
 	of_node_put(dn);
@@ -318,8 +323,12 @@ int pseries_devicetree_update(s32 scope)
 					add_dt_node(phandle, drc_index);
 					break;
 				}
+
+				cond_resched();
 			}
 		}
+
+		cond_resched();
 	} while (rc == 1);
 
 	kfree(rtas_buf);
-- 
2.20.1

[PATCH AUTOSEL 4.19 29/50] powerpc/eeh: Clear stale EEH_DEV_NO_HANDLER flag

[Sasha Levin]

From: Sam Bobroff <sbobroff@linux.ibm.com>

[ Upstream commit aa06e3d60e245284d1e55497eb3108828092818d ]

The EEH_DEV_NO_HANDLER flag is used by the EEH system to prevent the
use of driver callbacks in drivers that have been bound part way
through the recovery process. This is necessary to prevent later stage
handlers from being called when the earlier stage handlers haven't,
which can be confusing for drivers.

However, the flag is set for all devices that are added after boot
time and only cleared at the end of the EEH recovery process. This
results in hot plugged devices erroneously having the flag set during
the first recovery after they are added (causing their driver's
handlers to be incorrectly ignored).

To remedy this, clear the flag at the beginning of recovery
processing. The flag is still cleared at the end of recovery
processing, although it is no longer really necessary.

Also clear the flag during eeh_handle_special_event(), for the same
reasons.

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b8ca5629d27de74c957d4f4b250177d1b6fc4bbd.1565930772.git.sbobroff@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/eeh_driver.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index 67619b4b3f96c..110eba400de7c 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -811,6 +811,10 @@ void eeh_handle_normal_event(struct eeh_pe *pe)
 	pr_warn("EEH: This PCI device has failed %d times in the last hour and will be permanently disabled after %d failures.\n",
 		pe->freeze_count, eeh_max_freezes);
 
+	eeh_for_each_pe(pe, tmp_pe)
+		eeh_pe_for_each_dev(tmp_pe, edev, tmp)
+			edev->mode &= ~EEH_DEV_NO_HANDLER;
+
 	/* Walk the various device drivers attached to this slot through
 	 * a reset sequence, giving each an opportunity to do what it needs
 	 * to accomplish the reset.  Each child gets a report of the
@@ -1004,7 +1008,8 @@ void eeh_handle_normal_event(struct eeh_pe *pe)
  */
 void eeh_handle_special_event(void)
 {
-	struct eeh_pe *pe, *phb_pe;
+	struct eeh_pe *pe, *phb_pe, *tmp_pe;
+	struct eeh_dev *edev, *tmp_edev;
 	struct pci_bus *bus;
 	struct pci_controller *hose;
 	unsigned long flags;
@@ -1075,6 +1080,10 @@ void eeh_handle_special_event(void)
 				    (phb_pe->state & EEH_PE_RECOVERING))
 					continue;
 
+				eeh_for_each_pe(pe, tmp_pe)
+					eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev)
+						edev->mode &= ~EEH_DEV_NO_HANDLER;
+
 				/* Notify all devices to be down */
 				eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
 				eeh_set_channel_state(pe, pci_channel_io_perm_failure);
-- 
2.20.1

[PATCH AUTOSEL 4.19 37/50] powerpc/64s/exception: machine check use correct cfar for late handler

[Sasha Levin]

From: Nicholas Piggin <npiggin@gmail.com>

[ Upstream commit 0b66370c61fcf5fcc1d6901013e110284da6e2bb ]

Bare metal machine checks run an "early" handler in real mode before
running the main handler which reports the event.

The main handler runs exactly as a normal interrupt handler, after the
"windup" which sets registers back as they were at interrupt entry.
CFAR does not get restored by the windup code, so that will be wrong
when the handler is run.

Restore the CFAR to the saved value before running the late handler.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-8-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/exceptions-64s.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 06cc77813dbb7..90af86f143a91 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -520,6 +520,10 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
 	RFI_TO_USER_OR_KERNEL
 9:
 	/* Deliver the machine check to host kernel in V mode. */
+BEGIN_FTR_SECTION
+	ld	r10,ORIG_GPR3(r1)
+	mtspr	SPRN_CFAR,r10
+END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
 	MACHINE_CHECK_HANDLER_WINDUP
 	b	machine_check_pSeries
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 39/50] powerpc/imc: Dont create debugfs files for cpu-less nodes

[Sasha Levin]

From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>

[ Upstream commit 41ba17f20ea835c489e77bd54e2da73184e22060 ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/powernv/opal-imc.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
index 828f6656f8f74..649fb268f4461 100644
--- a/arch/powerpc/platforms/powernv/opal-imc.c
+++ b/arch/powerpc/platforms/powernv/opal-imc.c
@@ -57,9 +57,9 @@ static void export_imc_mode_and_cmd(struct device_node *node,
 				    struct imc_pmu *pmu_ptr)
 {
 	static u64 loc, *imc_mode_addr, *imc_cmd_addr;
-	int chip = 0, nid;
 	char mode[16], cmd[16];
 	u32 cb_offset;
+	struct imc_mem_info *ptr = pmu_ptr->mem_info;
 
 	imc_debugfs_parent = debugfs_create_dir("imc", powerpc_debugfs_root);
 
@@ -73,20 +73,20 @@ static void export_imc_mode_and_cmd(struct device_node *node,
 	if (of_property_read_u32(node, "cb_offset", &cb_offset))
 		cb_offset = IMC_CNTL_BLK_OFFSET;
 
-	for_each_node(nid) {
-		loc = (u64)(pmu_ptr->mem_info[chip].vbase) + cb_offset;
+	while (ptr->vbase != NULL) {
+		loc = (u64)(ptr->vbase) + cb_offset;
 		imc_mode_addr = (u64 *)(loc + IMC_CNTL_BLK_MODE_OFFSET);
-		sprintf(mode, "imc_mode_%d", nid);
+		sprintf(mode, "imc_mode_%d", (u32)(ptr->id));
 		if (!imc_debugfs_create_x64(mode, 0600, imc_debugfs_parent,
 					    imc_mode_addr))
 			goto err;
 
 		imc_cmd_addr = (u64 *)(loc + IMC_CNTL_BLK_CMD_OFFSET);
-		sprintf(cmd, "imc_cmd_%d", nid);
+		sprintf(cmd, "imc_cmd_%d", (u32)(ptr->id));
 		if (!imc_debugfs_create_x64(cmd, 0600, imc_debugfs_parent,
 					    imc_cmd_addr))
 			goto err;
-		chip++;
+		ptr++;
 	}
 	return;
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 41/50] powerpc/pseries: correctly track irq state in default idle

[Sasha Levin]

From: Nathan Lynch <nathanl@linux.ibm.com>

[ 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>
---
 arch/powerpc/platforms/pseries/setup.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index ba1791fd3234d..67f49159ea708 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -325,6 +325,9 @@ static void pseries_lpar_idle(void)
 	 * low power mode by ceding processor to hypervisor
 	 */
 
+	if (!prep_irq_for_idle())
+		return;
+
 	/* Indicate to hypervisor that we are idle. */
 	get_lppaca()->idle = 1;
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 45/50] powerpc: dump kernel log before carrying out fadump or kdump

[Sasha Levin]

From: Ganesh Goudar <ganeshgr@linux.ibm.com>

[ Upstream commit e7ca44ed3ba77fc26cf32650bb71584896662474 ]

Since commit 4388c9b3a6ee ("powerpc: Do not send system reset request
through the oops path"), pstore dmesg file is not updated when dump is
triggered from HMC. This commit modified system reset (sreset) handler
to invoke fadump or kdump (if configured), without pushing dmesg to
pstore. This leaves pstore to have old dmesg data which won't be much
of a help if kdump fails to capture the dump. This patch fixes that by
calling kmsg_dump() before heading to fadump ot kdump.

Fixes: 4388c9b3a6ee ("powerpc: Do not send system reset request through the oops path")
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190904075949.15607-1-ganeshgr@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/traps.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 02fe6d0201741..d5f351f02c153 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -399,6 +399,7 @@ void system_reset_exception(struct pt_regs *regs)
 	if (debugger(regs))
 		goto out;
 
+	kmsg_dump(KMSG_DUMP_OOPS);
 	/*
 	 * A system reset is a request to dump, so we always send
 	 * it through the crashdump code (if fadump or kdump are
-- 
2.20.1