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* [PATCH AUTOSEL 5.10 60/85] powerpc/smp: Set numa node before updating mask
From: Sasha Levin @ 2021-05-05 16:36 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Nathan Lynch, Sasha Levin, Srikar Dronamraju,
	Geetika Moolchandani, linuxppc-dev
In-Reply-To: <20210505163648.3462507-1-sashal@kernel.org>

From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

[ Upstream commit 6980d13f0dd189846887bbbfa43793d9a41768d3 ]

Geethika reported a trace when doing a dlpar CPU add.

------------[ cut here ]------------
WARNING: CPU: 152 PID: 1134 at kernel/sched/topology.c:2057
CPU: 152 PID: 1134 Comm: kworker/152:1 Not tainted 5.12.0-rc5-master #5
Workqueue: events cpuset_hotplug_workfn
NIP:  c0000000001cfc14 LR: c0000000001cfc10 CTR: c0000000007e3420
REGS: c0000034a08eb260 TRAP: 0700   Not tainted  (5.12.0-rc5-master+)
MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28828422  XER: 00000020
CFAR: c0000000001fd888 IRQMASK: 0 #012GPR00: c0000000001cfc10
c0000034a08eb500 c000000001f35400 0000000000000027 #012GPR04:
c0000035abaa8010 c0000035abb30a00 0000000000000027 c0000035abaa8018
#012GPR08: 0000000000000023 c0000035abaaef48 00000035aa540000
c0000035a49dffe8 #012GPR12: 0000000028828424 c0000035bf1a1c80
0000000000000497 0000000000000004 #012GPR16: c00000000347a258
0000000000000140 c00000000203d468 c000000001a1a490 #012GPR20:
c000000001f9c160 c0000034adf70920 c0000034aec9fd20 0000000100087bd3
#012GPR24: 0000000100087bd3 c0000035b3de09f8 0000000000000030
c0000035b3de09f8 #012GPR28: 0000000000000028 c00000000347a280
c0000034aefe0b00 c0000000010a2a68
NIP [c0000000001cfc14] build_sched_domains+0x6a4/0x1500
LR [c0000000001cfc10] build_sched_domains+0x6a0/0x1500
Call Trace:
[c0000034a08eb500] [c0000000001cfc10] build_sched_domains+0x6a0/0x1500 (unreliable)
[c0000034a08eb640] [c0000000001d1e6c] partition_sched_domains_locked+0x3ec/0x530
[c0000034a08eb6e0] [c0000000002936d4] rebuild_sched_domains_locked+0x524/0xbf0
[c0000034a08eb7e0] [c000000000296bb0] rebuild_sched_domains+0x40/0x70
[c0000034a08eb810] [c000000000296e74] cpuset_hotplug_workfn+0x294/0xe20
[c0000034a08ebc30] [c000000000178dd0] process_one_work+0x300/0x670
[c0000034a08ebd10] [c0000000001791b8] worker_thread+0x78/0x520
[c0000034a08ebda0] [c000000000185090] kthread+0x1a0/0x1b0
[c0000034a08ebe10] [c00000000000ccec] ret_from_kernel_thread+0x5c/0x70
Instruction dump:
7d2903a6 4e800421 e8410018 7f67db78 7fe6fb78 7f45d378 7f84e378 7c681b78
3c62ff1a 3863c6f8 4802dc35 60000000 <0fe00000> 3920fff4 f9210070 e86100a0
---[ end trace 532d9066d3d4d7ec ]---

Some of the per-CPU masks use cpu_cpu_mask as a filter to limit the search
for related CPUs. On a dlpar add of a CPU, update cpu_cpu_mask before
updating the per-CPU masks. This will ensure the cpu_cpu_mask is updated
correctly before its used in setting the masks. Setting the numa_node will
ensure that when cpu_cpu_mask() gets called, the correct node number is
used. This code movement helped fix the above call trace.

Reported-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210401154200.150077-1-srikar@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/smp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 7d6cf75a7fd8..85a1a2a9d8ed 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1417,6 +1417,9 @@ void start_secondary(void *unused)
 
 	vdso_getcpu_init();
 #endif
+	set_numa_node(numa_cpu_lookup_table[cpu]);
+	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
+
 	/* Update topology CPU masks */
 	add_cpu_to_masks(cpu);
 
@@ -1435,9 +1438,6 @@ void start_secondary(void *unused)
 			shared_caches = true;
 	}
 
-	set_numa_node(numa_cpu_lookup_table[cpu]);
-	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
-
 	smp_wmb();
 	notify_cpu_starting(cpu);
 	set_cpu_online(cpu, true);
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 5.10 65/85] powerpc/pseries: Stop calling printk in rtas_stop_self()
From: Sasha Levin @ 2021-05-05 16:36 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev
In-Reply-To: <20210505163648.3462507-1-sashal@kernel.org>

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit ed8029d7b472369a010a1901358567ca3b6dbb0d ]

RCU complains about us calling printk() from an offline CPU:

  =============================
  WARNING: suspicious RCU usage
  5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted
  -----------------------------
  kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by swapper/0/0.

  stack backtrace:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7-02874-g7cf90e481cb8 #1
  Call Trace:
    dump_stack+0xec/0x144 (unreliable)
    lockdep_rcu_suspicious+0x124/0x144
    __lock_acquire+0x1098/0x28b0
    lock_acquire+0x128/0x600
    _raw_spin_lock_irqsave+0x6c/0xc0
    down_trylock+0x2c/0x70
    __down_trylock_console_sem+0x60/0x140
    vprintk_emit+0x1a8/0x4b0
    vprintk_func+0xcc/0x200
    printk+0x40/0x54
    pseries_cpu_offline_self+0xc0/0x120
    arch_cpu_idle_dead+0x54/0x70
    do_idle+0x174/0x4a0
    cpu_startup_entry+0x38/0x40
    rest_init+0x268/0x388
    start_kernel+0x748/0x790
    start_here_common+0x1c/0x614

Which happens because by the time we get to rtas_stop_self() we are
already offline. In addition the message can be spammy, and is not that
helpful for users, so remove it.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210418135413.1204031-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 12cbffd3c2e3..325f3b220f36 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -47,9 +47,6 @@ static void rtas_stop_self(void)
 
 	BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
 
-	printk("cpu %u (hwid %u) Ready to die...\n",
-	       smp_processor_id(), hard_smp_processor_id());
-
 	rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
 
 	panic("Alas, I survived.\n");
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 5.10 74/85] powerpc/iommu: Annotate nested lock for lockdep
From: Sasha Levin @ 2021-05-05 16:36 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Alexey Kardashevskiy, linuxppc-dev, Sasha Levin
In-Reply-To: <20210505163648.3462507-1-sashal@kernel.org>

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit cc7130bf119add37f36238343a593b71ef6ecc1e ]

The IOMMU table is divided into pools for concurrent mappings and each
pool has a separate spinlock. When taking the ownership of an IOMMU group
to pass through a device to a VM, we lock these spinlocks which triggers
a false negative warning in lockdep (below).

This fixes it by annotating the large pool's spinlock as a nest lock
which makes lockdep not complaining when locking nested locks if
the nest lock is locked already.

===
WARNING: possible recursive locking detected
5.11.0-le_syzkaller_a+fstn1 #100 Not tainted
--------------------------------------------
qemu-system-ppc/4129 is trying to acquire lock:
c0000000119bddb0 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

but task is already holding lock:
c0000000119bdd30 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

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

       CPU0
       ----
  lock(&(p->lock)/1);
  lock(&(p->lock)/1);
===

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301063653.51003-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 5b69a6a72a0e..6806eefa52ce 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1050,7 +1050,7 @@ int iommu_take_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	iommu_table_release_pages(tbl);
 
@@ -1078,7 +1078,7 @@ void iommu_release_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	memset(tbl->it_map, 0, sz);
 
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 5.4 32/46] powerpc/smp: Set numa node before updating mask
From: Sasha Levin @ 2021-05-05 16:38 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Nathan Lynch, Sasha Levin, Srikar Dronamraju,
	Geetika Moolchandani, linuxppc-dev
In-Reply-To: <20210505163856.3463279-1-sashal@kernel.org>

From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

[ Upstream commit 6980d13f0dd189846887bbbfa43793d9a41768d3 ]

Geethika reported a trace when doing a dlpar CPU add.

------------[ cut here ]------------
WARNING: CPU: 152 PID: 1134 at kernel/sched/topology.c:2057
CPU: 152 PID: 1134 Comm: kworker/152:1 Not tainted 5.12.0-rc5-master #5
Workqueue: events cpuset_hotplug_workfn
NIP:  c0000000001cfc14 LR: c0000000001cfc10 CTR: c0000000007e3420
REGS: c0000034a08eb260 TRAP: 0700   Not tainted  (5.12.0-rc5-master+)
MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28828422  XER: 00000020
CFAR: c0000000001fd888 IRQMASK: 0 #012GPR00: c0000000001cfc10
c0000034a08eb500 c000000001f35400 0000000000000027 #012GPR04:
c0000035abaa8010 c0000035abb30a00 0000000000000027 c0000035abaa8018
#012GPR08: 0000000000000023 c0000035abaaef48 00000035aa540000
c0000035a49dffe8 #012GPR12: 0000000028828424 c0000035bf1a1c80
0000000000000497 0000000000000004 #012GPR16: c00000000347a258
0000000000000140 c00000000203d468 c000000001a1a490 #012GPR20:
c000000001f9c160 c0000034adf70920 c0000034aec9fd20 0000000100087bd3
#012GPR24: 0000000100087bd3 c0000035b3de09f8 0000000000000030
c0000035b3de09f8 #012GPR28: 0000000000000028 c00000000347a280
c0000034aefe0b00 c0000000010a2a68
NIP [c0000000001cfc14] build_sched_domains+0x6a4/0x1500
LR [c0000000001cfc10] build_sched_domains+0x6a0/0x1500
Call Trace:
[c0000034a08eb500] [c0000000001cfc10] build_sched_domains+0x6a0/0x1500 (unreliable)
[c0000034a08eb640] [c0000000001d1e6c] partition_sched_domains_locked+0x3ec/0x530
[c0000034a08eb6e0] [c0000000002936d4] rebuild_sched_domains_locked+0x524/0xbf0
[c0000034a08eb7e0] [c000000000296bb0] rebuild_sched_domains+0x40/0x70
[c0000034a08eb810] [c000000000296e74] cpuset_hotplug_workfn+0x294/0xe20
[c0000034a08ebc30] [c000000000178dd0] process_one_work+0x300/0x670
[c0000034a08ebd10] [c0000000001791b8] worker_thread+0x78/0x520
[c0000034a08ebda0] [c000000000185090] kthread+0x1a0/0x1b0
[c0000034a08ebe10] [c00000000000ccec] ret_from_kernel_thread+0x5c/0x70
Instruction dump:
7d2903a6 4e800421 e8410018 7f67db78 7fe6fb78 7f45d378 7f84e378 7c681b78
3c62ff1a 3863c6f8 4802dc35 60000000 <0fe00000> 3920fff4 f9210070 e86100a0
---[ end trace 532d9066d3d4d7ec ]---

Some of the per-CPU masks use cpu_cpu_mask as a filter to limit the search
for related CPUs. On a dlpar add of a CPU, update cpu_cpu_mask before
updating the per-CPU masks. This will ensure the cpu_cpu_mask is updated
correctly before its used in setting the masks. Setting the numa_node will
ensure that when cpu_cpu_mask() gets called, the correct node number is
used. This code movement helped fix the above call trace.

Reported-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210401154200.150077-1-srikar@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/smp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index ea6adbf6a221..b24d860bbab9 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1254,6 +1254,9 @@ void start_secondary(void *unused)
 
 	vdso_getcpu_init();
 #endif
+	set_numa_node(numa_cpu_lookup_table[cpu]);
+	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
+
 	/* Update topology CPU masks */
 	add_cpu_to_masks(cpu);
 
@@ -1266,9 +1269,6 @@ void start_secondary(void *unused)
 	if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu)))
 		shared_caches = true;
 
-	set_numa_node(numa_cpu_lookup_table[cpu]);
-	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
-
 	smp_wmb();
 	notify_cpu_starting(cpu);
 	set_cpu_online(cpu, true);
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 5.4 37/46] powerpc/pseries: Stop calling printk in rtas_stop_self()
From: Sasha Levin @ 2021-05-05 16:38 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev
In-Reply-To: <20210505163856.3463279-1-sashal@kernel.org>

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit ed8029d7b472369a010a1901358567ca3b6dbb0d ]

RCU complains about us calling printk() from an offline CPU:

  =============================
  WARNING: suspicious RCU usage
  5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted
  -----------------------------
  kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by swapper/0/0.

  stack backtrace:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7-02874-g7cf90e481cb8 #1
  Call Trace:
    dump_stack+0xec/0x144 (unreliable)
    lockdep_rcu_suspicious+0x124/0x144
    __lock_acquire+0x1098/0x28b0
    lock_acquire+0x128/0x600
    _raw_spin_lock_irqsave+0x6c/0xc0
    down_trylock+0x2c/0x70
    __down_trylock_console_sem+0x60/0x140
    vprintk_emit+0x1a8/0x4b0
    vprintk_func+0xcc/0x200
    printk+0x40/0x54
    pseries_cpu_offline_self+0xc0/0x120
    arch_cpu_idle_dead+0x54/0x70
    do_idle+0x174/0x4a0
    cpu_startup_entry+0x38/0x40
    rest_init+0x268/0x388
    start_kernel+0x748/0x790
    start_here_common+0x1c/0x614

Which happens because by the time we get to rtas_stop_self() we are
already offline. In addition the message can be spammy, and is not that
helpful for users, so remove it.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210418135413.1204031-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index bbda646b63b5..210e6f563eb4 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -91,9 +91,6 @@ static void rtas_stop_self(void)
 
 	BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
 
-	printk("cpu %u (hwid %u) Ready to die...\n",
-	       smp_processor_id(), hard_smp_processor_id());
-
 	rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
 
 	panic("Alas, I survived.\n");
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 5.4 42/46] powerpc/iommu: Annotate nested lock for lockdep
From: Sasha Levin @ 2021-05-05 16:38 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Alexey Kardashevskiy, linuxppc-dev, Sasha Levin
In-Reply-To: <20210505163856.3463279-1-sashal@kernel.org>

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit cc7130bf119add37f36238343a593b71ef6ecc1e ]

The IOMMU table is divided into pools for concurrent mappings and each
pool has a separate spinlock. When taking the ownership of an IOMMU group
to pass through a device to a VM, we lock these spinlocks which triggers
a false negative warning in lockdep (below).

This fixes it by annotating the large pool's spinlock as a nest lock
which makes lockdep not complaining when locking nested locks if
the nest lock is locked already.

===
WARNING: possible recursive locking detected
5.11.0-le_syzkaller_a+fstn1 #100 Not tainted
--------------------------------------------
qemu-system-ppc/4129 is trying to acquire lock:
c0000000119bddb0 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

but task is already holding lock:
c0000000119bdd30 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

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

       CPU0
       ----
  lock(&(p->lock)/1);
  lock(&(p->lock)/1);
===

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301063653.51003-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 9704f3f76e63..d7d42bd448c4 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1057,7 +1057,7 @@ int iommu_take_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	iommu_table_release_pages(tbl);
 
@@ -1085,7 +1085,7 @@ void iommu_release_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	memset(tbl->it_map, 0, sz);
 
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.19 23/32] powerpc/smp: Set numa node before updating mask
From: Sasha Levin @ 2021-05-05 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Nathan Lynch, Sasha Levin, Srikar Dronamraju,
	Geetika Moolchandani, linuxppc-dev
In-Reply-To: <20210505164004.3463707-1-sashal@kernel.org>

From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

[ Upstream commit 6980d13f0dd189846887bbbfa43793d9a41768d3 ]

Geethika reported a trace when doing a dlpar CPU add.

------------[ cut here ]------------
WARNING: CPU: 152 PID: 1134 at kernel/sched/topology.c:2057
CPU: 152 PID: 1134 Comm: kworker/152:1 Not tainted 5.12.0-rc5-master #5
Workqueue: events cpuset_hotplug_workfn
NIP:  c0000000001cfc14 LR: c0000000001cfc10 CTR: c0000000007e3420
REGS: c0000034a08eb260 TRAP: 0700   Not tainted  (5.12.0-rc5-master+)
MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28828422  XER: 00000020
CFAR: c0000000001fd888 IRQMASK: 0 #012GPR00: c0000000001cfc10
c0000034a08eb500 c000000001f35400 0000000000000027 #012GPR04:
c0000035abaa8010 c0000035abb30a00 0000000000000027 c0000035abaa8018
#012GPR08: 0000000000000023 c0000035abaaef48 00000035aa540000
c0000035a49dffe8 #012GPR12: 0000000028828424 c0000035bf1a1c80
0000000000000497 0000000000000004 #012GPR16: c00000000347a258
0000000000000140 c00000000203d468 c000000001a1a490 #012GPR20:
c000000001f9c160 c0000034adf70920 c0000034aec9fd20 0000000100087bd3
#012GPR24: 0000000100087bd3 c0000035b3de09f8 0000000000000030
c0000035b3de09f8 #012GPR28: 0000000000000028 c00000000347a280
c0000034aefe0b00 c0000000010a2a68
NIP [c0000000001cfc14] build_sched_domains+0x6a4/0x1500
LR [c0000000001cfc10] build_sched_domains+0x6a0/0x1500
Call Trace:
[c0000034a08eb500] [c0000000001cfc10] build_sched_domains+0x6a0/0x1500 (unreliable)
[c0000034a08eb640] [c0000000001d1e6c] partition_sched_domains_locked+0x3ec/0x530
[c0000034a08eb6e0] [c0000000002936d4] rebuild_sched_domains_locked+0x524/0xbf0
[c0000034a08eb7e0] [c000000000296bb0] rebuild_sched_domains+0x40/0x70
[c0000034a08eb810] [c000000000296e74] cpuset_hotplug_workfn+0x294/0xe20
[c0000034a08ebc30] [c000000000178dd0] process_one_work+0x300/0x670
[c0000034a08ebd10] [c0000000001791b8] worker_thread+0x78/0x520
[c0000034a08ebda0] [c000000000185090] kthread+0x1a0/0x1b0
[c0000034a08ebe10] [c00000000000ccec] ret_from_kernel_thread+0x5c/0x70
Instruction dump:
7d2903a6 4e800421 e8410018 7f67db78 7fe6fb78 7f45d378 7f84e378 7c681b78
3c62ff1a 3863c6f8 4802dc35 60000000 <0fe00000> 3920fff4 f9210070 e86100a0
---[ end trace 532d9066d3d4d7ec ]---

Some of the per-CPU masks use cpu_cpu_mask as a filter to limit the search
for related CPUs. On a dlpar add of a CPU, update cpu_cpu_mask before
updating the per-CPU masks. This will ensure the cpu_cpu_mask is updated
correctly before its used in setting the masks. Setting the numa_node will
ensure that when cpu_cpu_mask() gets called, the correct node number is
used. This code movement helped fix the above call trace.

Reported-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210401154200.150077-1-srikar@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/smp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 6dc43205382b..a9ec4467705c 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1032,6 +1032,9 @@ void start_secondary(void *unused)
 
 	vdso_getcpu_init();
 #endif
+	set_numa_node(numa_cpu_lookup_table[cpu]);
+	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
+
 	/* Update topology CPU masks */
 	add_cpu_to_masks(cpu);
 
@@ -1042,9 +1045,6 @@ void start_secondary(void *unused)
 	if (!cpumask_equal(cpu_l2_cache_mask(cpu), cpu_sibling_mask(cpu)))
 		shared_caches = true;
 
-	set_numa_node(numa_cpu_lookup_table[cpu]);
-	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
-
 	smp_wmb();
 	notify_cpu_starting(cpu);
 	set_cpu_online(cpu, true);
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.19 27/32] powerpc/pseries: Stop calling printk in rtas_stop_self()
From: Sasha Levin @ 2021-05-05 16:39 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev
In-Reply-To: <20210505164004.3463707-1-sashal@kernel.org>

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit ed8029d7b472369a010a1901358567ca3b6dbb0d ]

RCU complains about us calling printk() from an offline CPU:

  =============================
  WARNING: suspicious RCU usage
  5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted
  -----------------------------
  kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by swapper/0/0.

  stack backtrace:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7-02874-g7cf90e481cb8 #1
  Call Trace:
    dump_stack+0xec/0x144 (unreliable)
    lockdep_rcu_suspicious+0x124/0x144
    __lock_acquire+0x1098/0x28b0
    lock_acquire+0x128/0x600
    _raw_spin_lock_irqsave+0x6c/0xc0
    down_trylock+0x2c/0x70
    __down_trylock_console_sem+0x60/0x140
    vprintk_emit+0x1a8/0x4b0
    vprintk_func+0xcc/0x200
    printk+0x40/0x54
    pseries_cpu_offline_self+0xc0/0x120
    arch_cpu_idle_dead+0x54/0x70
    do_idle+0x174/0x4a0
    cpu_startup_entry+0x38/0x40
    rest_init+0x268/0x388
    start_kernel+0x748/0x790
    start_here_common+0x1c/0x614

Which happens because by the time we get to rtas_stop_self() we are
already offline. In addition the message can be spammy, and is not that
helpful for users, so remove it.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210418135413.1204031-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 1d3f9313c02f..8bfb97d07d10 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -95,9 +95,6 @@ static void rtas_stop_self(void)
 
 	BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
 
-	printk("cpu %u (hwid %u) Ready to die...\n",
-	       smp_processor_id(), hard_smp_processor_id());
-
 	rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
 
 	panic("Alas, I survived.\n");
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.19 30/32] powerpc/iommu: Annotate nested lock for lockdep
From: Sasha Levin @ 2021-05-05 16:40 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Alexey Kardashevskiy, linuxppc-dev, Sasha Levin
In-Reply-To: <20210505164004.3463707-1-sashal@kernel.org>

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit cc7130bf119add37f36238343a593b71ef6ecc1e ]

The IOMMU table is divided into pools for concurrent mappings and each
pool has a separate spinlock. When taking the ownership of an IOMMU group
to pass through a device to a VM, we lock these spinlocks which triggers
a false negative warning in lockdep (below).

This fixes it by annotating the large pool's spinlock as a nest lock
which makes lockdep not complaining when locking nested locks if
the nest lock is locked already.

===
WARNING: possible recursive locking detected
5.11.0-le_syzkaller_a+fstn1 #100 Not tainted
--------------------------------------------
qemu-system-ppc/4129 is trying to acquire lock:
c0000000119bddb0 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

but task is already holding lock:
c0000000119bdd30 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

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

       CPU0
       ----
  lock(&(p->lock)/1);
  lock(&(p->lock)/1);
===

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301063653.51003-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index f0dc680e659a..c3d2d5cd7c10 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1030,7 +1030,7 @@ int iommu_take_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	if (tbl->it_offset == 0)
 		clear_bit(0, tbl->it_map);
@@ -1059,7 +1059,7 @@ void iommu_release_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	memset(tbl->it_map, 0, sz);
 
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.14 18/25] powerpc/smp: Set numa node before updating mask
From: Sasha Levin @ 2021-05-05 16:40 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Nathan Lynch, Sasha Levin, Srikar Dronamraju,
	Geetika Moolchandani, linuxppc-dev
In-Reply-To: <20210505164051.3464020-1-sashal@kernel.org>

From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

[ Upstream commit 6980d13f0dd189846887bbbfa43793d9a41768d3 ]

Geethika reported a trace when doing a dlpar CPU add.

------------[ cut here ]------------
WARNING: CPU: 152 PID: 1134 at kernel/sched/topology.c:2057
CPU: 152 PID: 1134 Comm: kworker/152:1 Not tainted 5.12.0-rc5-master #5
Workqueue: events cpuset_hotplug_workfn
NIP:  c0000000001cfc14 LR: c0000000001cfc10 CTR: c0000000007e3420
REGS: c0000034a08eb260 TRAP: 0700   Not tainted  (5.12.0-rc5-master+)
MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28828422  XER: 00000020
CFAR: c0000000001fd888 IRQMASK: 0 #012GPR00: c0000000001cfc10
c0000034a08eb500 c000000001f35400 0000000000000027 #012GPR04:
c0000035abaa8010 c0000035abb30a00 0000000000000027 c0000035abaa8018
#012GPR08: 0000000000000023 c0000035abaaef48 00000035aa540000
c0000035a49dffe8 #012GPR12: 0000000028828424 c0000035bf1a1c80
0000000000000497 0000000000000004 #012GPR16: c00000000347a258
0000000000000140 c00000000203d468 c000000001a1a490 #012GPR20:
c000000001f9c160 c0000034adf70920 c0000034aec9fd20 0000000100087bd3
#012GPR24: 0000000100087bd3 c0000035b3de09f8 0000000000000030
c0000035b3de09f8 #012GPR28: 0000000000000028 c00000000347a280
c0000034aefe0b00 c0000000010a2a68
NIP [c0000000001cfc14] build_sched_domains+0x6a4/0x1500
LR [c0000000001cfc10] build_sched_domains+0x6a0/0x1500
Call Trace:
[c0000034a08eb500] [c0000000001cfc10] build_sched_domains+0x6a0/0x1500 (unreliable)
[c0000034a08eb640] [c0000000001d1e6c] partition_sched_domains_locked+0x3ec/0x530
[c0000034a08eb6e0] [c0000000002936d4] rebuild_sched_domains_locked+0x524/0xbf0
[c0000034a08eb7e0] [c000000000296bb0] rebuild_sched_domains+0x40/0x70
[c0000034a08eb810] [c000000000296e74] cpuset_hotplug_workfn+0x294/0xe20
[c0000034a08ebc30] [c000000000178dd0] process_one_work+0x300/0x670
[c0000034a08ebd10] [c0000000001791b8] worker_thread+0x78/0x520
[c0000034a08ebda0] [c000000000185090] kthread+0x1a0/0x1b0
[c0000034a08ebe10] [c00000000000ccec] ret_from_kernel_thread+0x5c/0x70
Instruction dump:
7d2903a6 4e800421 e8410018 7f67db78 7fe6fb78 7f45d378 7f84e378 7c681b78
3c62ff1a 3863c6f8 4802dc35 60000000 <0fe00000> 3920fff4 f9210070 e86100a0
---[ end trace 532d9066d3d4d7ec ]---

Some of the per-CPU masks use cpu_cpu_mask as a filter to limit the search
for related CPUs. On a dlpar add of a CPU, update cpu_cpu_mask before
updating the per-CPU masks. This will ensure the cpu_cpu_mask is updated
correctly before its used in setting the masks. Setting the numa_node will
ensure that when cpu_cpu_mask() gets called, the correct node number is
used. This code movement helped fix the above call trace.

Reported-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210401154200.150077-1-srikar@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/smp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index e0a4c1f82e25..7c7aa7c98ba3 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -985,6 +985,9 @@ void start_secondary(void *unused)
 
 	vdso_getcpu_init();
 #endif
+	set_numa_node(numa_cpu_lookup_table[cpu]);
+	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
+
 	/* Update topology CPU masks */
 	add_cpu_to_masks(cpu);
 
@@ -995,9 +998,6 @@ void start_secondary(void *unused)
 	if (!cpumask_equal(cpu_l2_cache_mask(cpu), cpu_sibling_mask(cpu)))
 		shared_caches = true;
 
-	set_numa_node(numa_cpu_lookup_table[cpu]);
-	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
-
 	smp_wmb();
 	notify_cpu_starting(cpu);
 	set_cpu_online(cpu, true);
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.14 21/25] powerpc/pseries: Stop calling printk in rtas_stop_self()
From: Sasha Levin @ 2021-05-05 16:40 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev
In-Reply-To: <20210505164051.3464020-1-sashal@kernel.org>

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit ed8029d7b472369a010a1901358567ca3b6dbb0d ]

RCU complains about us calling printk() from an offline CPU:

  =============================
  WARNING: suspicious RCU usage
  5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted
  -----------------------------
  kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by swapper/0/0.

  stack backtrace:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7-02874-g7cf90e481cb8 #1
  Call Trace:
    dump_stack+0xec/0x144 (unreliable)
    lockdep_rcu_suspicious+0x124/0x144
    __lock_acquire+0x1098/0x28b0
    lock_acquire+0x128/0x600
    _raw_spin_lock_irqsave+0x6c/0xc0
    down_trylock+0x2c/0x70
    __down_trylock_console_sem+0x60/0x140
    vprintk_emit+0x1a8/0x4b0
    vprintk_func+0xcc/0x200
    printk+0x40/0x54
    pseries_cpu_offline_self+0xc0/0x120
    arch_cpu_idle_dead+0x54/0x70
    do_idle+0x174/0x4a0
    cpu_startup_entry+0x38/0x40
    rest_init+0x268/0x388
    start_kernel+0x748/0x790
    start_here_common+0x1c/0x614

Which happens because by the time we get to rtas_stop_self() we are
already offline. In addition the message can be spammy, and is not that
helpful for users, so remove it.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210418135413.1204031-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 0baaaa6b0929..73071c4339c5 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -95,9 +95,6 @@ static void rtas_stop_self(void)
 
 	BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
 
-	printk("cpu %u (hwid %u) Ready to die...\n",
-	       smp_processor_id(), hard_smp_processor_id());
-
 	rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
 
 	panic("Alas, I survived.\n");
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.14 24/25] powerpc/iommu: Annotate nested lock for lockdep
From: Sasha Levin @ 2021-05-05 16:40 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Alexey Kardashevskiy, linuxppc-dev, Sasha Levin
In-Reply-To: <20210505164051.3464020-1-sashal@kernel.org>

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit cc7130bf119add37f36238343a593b71ef6ecc1e ]

The IOMMU table is divided into pools for concurrent mappings and each
pool has a separate spinlock. When taking the ownership of an IOMMU group
to pass through a device to a VM, we lock these spinlocks which triggers
a false negative warning in lockdep (below).

This fixes it by annotating the large pool's spinlock as a nest lock
which makes lockdep not complaining when locking nested locks if
the nest lock is locked already.

===
WARNING: possible recursive locking detected
5.11.0-le_syzkaller_a+fstn1 #100 Not tainted
--------------------------------------------
qemu-system-ppc/4129 is trying to acquire lock:
c0000000119bddb0 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

but task is already holding lock:
c0000000119bdd30 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

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

       CPU0
       ----
  lock(&(p->lock)/1);
  lock(&(p->lock)/1);
===

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301063653.51003-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 80b6caaa9b92..87af91937c8a 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1055,7 +1055,7 @@ int iommu_take_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	if (tbl->it_offset == 0)
 		clear_bit(0, tbl->it_map);
@@ -1084,7 +1084,7 @@ void iommu_release_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	memset(tbl->it_map, 0, sz);
 
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.9 18/22] powerpc/pseries: Stop calling printk in rtas_stop_self()
From: Sasha Levin @ 2021-05-05 16:41 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev
In-Reply-To: <20210505164129.3464277-1-sashal@kernel.org>

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit ed8029d7b472369a010a1901358567ca3b6dbb0d ]

RCU complains about us calling printk() from an offline CPU:

  =============================
  WARNING: suspicious RCU usage
  5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted
  -----------------------------
  kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by swapper/0/0.

  stack backtrace:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7-02874-g7cf90e481cb8 #1
  Call Trace:
    dump_stack+0xec/0x144 (unreliable)
    lockdep_rcu_suspicious+0x124/0x144
    __lock_acquire+0x1098/0x28b0
    lock_acquire+0x128/0x600
    _raw_spin_lock_irqsave+0x6c/0xc0
    down_trylock+0x2c/0x70
    __down_trylock_console_sem+0x60/0x140
    vprintk_emit+0x1a8/0x4b0
    vprintk_func+0xcc/0x200
    printk+0x40/0x54
    pseries_cpu_offline_self+0xc0/0x120
    arch_cpu_idle_dead+0x54/0x70
    do_idle+0x174/0x4a0
    cpu_startup_entry+0x38/0x40
    rest_init+0x268/0x388
    start_kernel+0x748/0x790
    start_here_common+0x1c/0x614

Which happens because by the time we get to rtas_stop_self() we are
already offline. In addition the message can be spammy, and is not that
helpful for users, so remove it.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210418135413.1204031-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 7a2beedb9740..a7d9dd029850 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -92,9 +92,6 @@ static void rtas_stop_self(void)
 
 	BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
 
-	printk("cpu %u (hwid %u) Ready to die...\n",
-	       smp_processor_id(), hard_smp_processor_id());
-
 	rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
 
 	panic("Alas, I survived.\n");
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.9 21/22] powerpc/iommu: Annotate nested lock for lockdep
From: Sasha Levin @ 2021-05-05 16:41 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Alexey Kardashevskiy, linuxppc-dev, Sasha Levin
In-Reply-To: <20210505164129.3464277-1-sashal@kernel.org>

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit cc7130bf119add37f36238343a593b71ef6ecc1e ]

The IOMMU table is divided into pools for concurrent mappings and each
pool has a separate spinlock. When taking the ownership of an IOMMU group
to pass through a device to a VM, we lock these spinlocks which triggers
a false negative warning in lockdep (below).

This fixes it by annotating the large pool's spinlock as a nest lock
which makes lockdep not complaining when locking nested locks if
the nest lock is locked already.

===
WARNING: possible recursive locking detected
5.11.0-le_syzkaller_a+fstn1 #100 Not tainted
--------------------------------------------
qemu-system-ppc/4129 is trying to acquire lock:
c0000000119bddb0 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

but task is already holding lock:
c0000000119bdd30 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

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

       CPU0
       ----
  lock(&(p->lock)/1);
  lock(&(p->lock)/1);
===

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301063653.51003-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 9bfdd2510fd5..2cf900d16527 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1021,7 +1021,7 @@ int iommu_take_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	if (tbl->it_offset == 0)
 		clear_bit(0, tbl->it_map);
@@ -1050,7 +1050,7 @@ void iommu_release_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	memset(tbl->it_map, 0, sz);
 
-- 
2.30.2


^ permalink raw reply related

* [PATCH AUTOSEL 4.4 19/19] powerpc/iommu: Annotate nested lock for lockdep
From: Sasha Levin @ 2021-05-05 16:42 UTC (permalink / raw)
  To: linux-kernel, stable; +Cc: Alexey Kardashevskiy, linuxppc-dev, Sasha Levin
In-Reply-To: <20210505164203.3464510-1-sashal@kernel.org>

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit cc7130bf119add37f36238343a593b71ef6ecc1e ]

The IOMMU table is divided into pools for concurrent mappings and each
pool has a separate spinlock. When taking the ownership of an IOMMU group
to pass through a device to a VM, we lock these spinlocks which triggers
a false negative warning in lockdep (below).

This fixes it by annotating the large pool's spinlock as a nest lock
which makes lockdep not complaining when locking nested locks if
the nest lock is locked already.

===
WARNING: possible recursive locking detected
5.11.0-le_syzkaller_a+fstn1 #100 Not tainted
--------------------------------------------
qemu-system-ppc/4129 is trying to acquire lock:
c0000000119bddb0 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

but task is already holding lock:
c0000000119bdd30 (&(p->lock)/1){....}-{2:2}, at: iommu_take_ownership+0xac/0x1e0

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

       CPU0
       ----
  lock(&(p->lock)/1);
  lock(&(p->lock)/1);
===

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210301063653.51003-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 4c9b5970af37..282ad1930593 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1019,7 +1019,7 @@ int iommu_take_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	if (tbl->it_offset == 0)
 		clear_bit(0, tbl->it_map);
@@ -1048,7 +1048,7 @@ void iommu_release_ownership(struct iommu_table *tbl)
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
-		spin_lock(&tbl->pools[i].lock);
+		spin_lock_nest_lock(&tbl->pools[i].lock, &tbl->large_pool.lock);
 
 	memset(tbl->it_map, 0, sz);
 
-- 
2.30.2


^ permalink raw reply related

* Re: [PATCH] kbuild: replace LANG=C with LC_ALL=C
From: Masahiro Yamada @ 2021-05-05 17:49 UTC (permalink / raw)
  To: Matthieu Baerts
  Cc: linuxppc-dev, Linux Kbuild mailing list, Mat Martineau,
	Matthias Maennich, Linux Kernel Mailing List, Networking,
	Paul Mackerras, mptcp, open list:KERNEL SELFTEST FRAMEWORK,
	Jakub Kicinski, Shuah Khan, David S. Miller
In-Reply-To: <2f8ccc46-16a1-e0fe-7cb0-0912295153ee@tessares.net>

On Tue, Apr 27, 2021 at 4:30 AM Matthieu Baerts
<matthieu.baerts@tessares.net> wrote:
>
> Hi,
>
> Thank you for the patch!
>
> On 24/04/2021 13:48, Masahiro Yamada wrote:
> > LANG gives a weak default to each LC_* in case it is not explicitly
> > defined. LC_ALL, if set, overrides all other LC_* variables.
> >
> >   LANG  <  LC_CTYPE, LC_COLLATE, LC_MONETARY, LC_NUMERIC, ...  <  LC_ALL
> >
> > This is why documentation such as [1] suggests to set LC_ALL in build
> > scripts to get the deterministic result.
> >
> > LANG=C is not strong enough to override LC_* that may be set by end
> > users.
> >
> > [1]: https://reproducible-builds.org/docs/locales/
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> > ---
> >
> >  arch/powerpc/boot/wrapper                          | 2 +-
> >  scripts/nsdeps                                     | 2 +-
> >  scripts/recordmcount.pl                            | 2 +-
> >  scripts/setlocalversion                            | 2 +-
> >  scripts/tags.sh                                    | 2 +-
> >  tools/testing/selftests/net/mptcp/mptcp_connect.sh | 2 +-
>
> Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net> (mptcp)
>
> Cheers,
> Matt
> --
> Tessares | Belgium | Hybrid Access Solutions
> www.tessares.net


Applied to linux-kbuild.


-- 
Best Regards
Masahiro Yamada

^ permalink raw reply

* [PATCH v2] powerpc/papr_scm: Reduce error severity if nvdimm stats inaccessible
From: Vaibhav Jain @ 2021-05-05 19:16 UTC (permalink / raw)
  To: linuxppc-dev, linux-nvdimm
  Cc: Santosh Sivaraj, Aneesh Kumar K . V, Vaibhav Jain, Dan Williams,
	Ira Weiny

Currently drc_pmem_qeury_stats() generates a dev_err in case
"Enable Performance Information Collection" feature is disabled from
HMC or performance stats are not available for an nvdimm. The error is
of the form below:

papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Failed to query
	 performance stats, Err:-10

This error message confuses users as it implies a possible problem
with the nvdimm even though its due to a disabled/unavailable
feature. We fix this by explicitly handling the H_AUTHORITY and
H_UNSUPPORTED errors from the H_SCM_PERFORMANCE_STATS hcall.

In case of H_AUTHORITY error an info message is logged instead of an
error, saying that "Permission denied while accessing performance
stats". Also '-EACCES' error is return instead of -EPERM.

In case of H_UNSUPPORTED error we return a -EPERM error back from
drc_pmem_query_stats() indicating that performance stats-query
operation is not supported on this nvdimm.

Fixes: 2d02bf835e57('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP')
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
Changelog

v2:
* Updated the message logged in case of H_AUTHORITY error [ Ira ]
* Switched from dev_warn to dev_info in case of H_AUTHORITY error.
* Instead of -EPERM return -EACCESS for H_AUTHORITY error.
* Added explicit handling of H_UNSUPPORTED error.
---
 arch/powerpc/platforms/pseries/papr_scm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index ef26fe40efb0..12f1513f0fca 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -310,6 +310,13 @@ static ssize_t drc_pmem_query_stats(struct papr_scm_priv *p,
 		dev_err(&p->pdev->dev,
 			"Unknown performance stats, Err:0x%016lX\n", ret[0]);
 		return -ENOENT;
+	} else if (rc == H_AUTHORITY) {
+		dev_info(&p->pdev->dev,
+			 "Permission denied while accessing performance stats");
+		return -EACCES;
+	} else if (rc == H_UNSUPPORTED) {
+		dev_dbg(&p->pdev->dev, "Performance stats unsupported\n");
+		return -EPERM;
 	} else if (rc != H_SUCCESS) {
 		dev_err(&p->pdev->dev,
 			"Failed to query performance stats, Err:%lld\n", rc);
-- 
2.31.1


^ permalink raw reply related

* [PATCH] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable
From: Vaibhav Jain @ 2021-05-05 19:17 UTC (permalink / raw)
  To: linuxppc-dev, linux-nvdimm
  Cc: Santosh Sivaraj, Aneesh Kumar K . V, Vaibhav Jain, Dan Williams,
	Ira Weiny

In case performance stats for an nvdimm are not available, reading the
'perf_stats' sysfs file returns an -ENOENT error. A better approach is
to make the 'perf_stats' file entirely invisible to indicate that
performance stats for an nvdimm are unavailable.

So this patch updates 'papr_nd_attribute_group' to add a 'is_visible'
callback implemented as newly introduced 'papr_nd_attribute_visible()'
that returns an appropriate mode in case performance stats aren't
supported in a given nvdimm.

Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved
from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is
available when 'papr_nd_attribute_visible()' is called during nvdimm
initialization.

Fixes: 2d02bf835e57('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP')
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/papr_scm.c | 37 ++++++++++++++++-------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 12f1513f0fca..90f0af8fefe8 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -907,6 +907,20 @@ static ssize_t flags_show(struct device *dev,
 }
 DEVICE_ATTR_RO(flags);
 
+umode_t papr_nd_attribute_visible(struct kobject *kobj, struct attribute *attr,
+				  int n)
+{
+	struct device *dev = container_of(kobj, typeof(*dev), kobj);
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct papr_scm_priv *p = nvdimm_provider_data(nvdimm);
+
+	/* For if perf-stats not available remove perf_stats sysfs */
+	if (attr == &dev_attr_perf_stats.attr && p->stat_buffer_len == 0)
+		return 0;
+
+	return attr->mode;
+}
+
 /* papr_scm specific dimm attributes */
 static struct attribute *papr_nd_attributes[] = {
 	&dev_attr_flags.attr,
@@ -916,6 +930,7 @@ static struct attribute *papr_nd_attributes[] = {
 
 static struct attribute_group papr_nd_attribute_group = {
 	.name = "papr",
+	.is_visible = papr_nd_attribute_visible,
 	.attrs = papr_nd_attributes,
 };
 
@@ -931,7 +946,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	struct nd_region_desc ndr_desc;
 	unsigned long dimm_flags;
 	int target_nid, online_nid;
-	ssize_t stat_size;
 
 	p->bus_desc.ndctl = papr_scm_ndctl;
 	p->bus_desc.module = THIS_MODULE;
@@ -1016,16 +1030,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	list_add_tail(&p->region_list, &papr_nd_regions);
 	mutex_unlock(&papr_ndr_lock);
 
-	/* Try retriving the stat buffer and see if its supported */
-	stat_size = drc_pmem_query_stats(p, NULL, 0);
-	if (stat_size > 0) {
-		p->stat_buffer_len = stat_size;
-		dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
-			p->stat_buffer_len);
-	} else {
-		dev_info(&p->pdev->dev, "Dimm performance stats unavailable\n");
-	}
-
 	return 0;
 
 err:	nvdimm_bus_unregister(p->bus);
@@ -1102,6 +1106,7 @@ static int papr_scm_probe(struct platform_device *pdev)
 	u64 blocks, block_size;
 	struct papr_scm_priv *p;
 	const char *uuid_str;
+	ssize_t stat_size;
 	u64 uuid[2];
 	int rc;
 
@@ -1179,6 +1184,16 @@ static int papr_scm_probe(struct platform_device *pdev)
 	p->res.name  = pdev->name;
 	p->res.flags = IORESOURCE_MEM;
 
+	/* Try retriving the stat buffer and see if its supported */
+	stat_size = drc_pmem_query_stats(p, NULL, 0);
+	if (stat_size > 0) {
+		p->stat_buffer_len = stat_size;
+		dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
+			p->stat_buffer_len);
+	} else {
+		dev_info(&p->pdev->dev, "Dimm performance stats unavailable\n");
+	}
+
 	rc = papr_scm_nvdimm_init(p);
 	if (rc)
 		goto err2;
-- 
2.31.1


^ permalink raw reply related

* [PATCH] cxl: Fix an error message
From: Christophe JAILLET @ 2021-05-05 19:38 UTC (permalink / raw)
  To: fbarrat, ajd, arnd, gregkh, mpe, imunsie, mikey
  Cc: kernel-janitors, Christophe JAILLET, linuxppc-dev, linux-kernel

'rc' is known to be 0 here.
Initialize 'rc' with the expected error code before using it.

While at it, avoid the affectation of 'rc' in a 'if' to make things more
obvious and linux style.

Fixes: f204e0b8ce ("cxl: Driver code for powernv PCIe based cards for userspace access")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/misc/cxl/file.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index bd3bd32333c5..3dbdce96fae0 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -569,7 +569,8 @@ static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 	int rc;
 
 	cdev_init(cdev, fops);
-	if ((rc = cdev_add(cdev, devt, 1))) {
+	rc = cdev_add(cdev, devt, 1);
+	if (rc) {
 		dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
 		return rc;
 	}
@@ -577,8 +578,8 @@ static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 	dev = device_create(cxl_class, &afu->dev, devt, afu,
 			"afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
 	if (IS_ERR(dev)) {
-		dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
 		rc = PTR_ERR(dev);
+		dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
 		goto err;
 	}
 
-- 
2.30.2


^ permalink raw reply related

* Re: [PATCH] KVM: PPC: Book3S HV: Fix conversion to gfn-based MMU notifier callbacks
From: Sean Christopherson @ 2021-05-05 15:52 UTC (permalink / raw)
  To: Nicholas Piggin
  Cc: kvm, Aneesh Kumar K . V, kvm-ppc, Bharata B Rao, Paolo Bonzini,
	linuxppc-dev
In-Reply-To: <20210505121509.1470207-1-npiggin@gmail.com>

On Wed, May 05, 2021, Nicholas Piggin wrote:
> Commit b1c5356e873c ("KVM: PPC: Convert to the gfn-based MMU notifier
> callbacks") causes unmap_gfn_range and age_gfn callbacks to only work
> on the first gfn in the range. It also makes the aging callbacks call
> into both radix and hash aging functions for radix guests. Fix this.

Ugh, the rest of kvm_handle_hva_range() was so similar to the x86 code that I
glossed right over the for-loop.  My apologies :-/

> Add warnings for the single-gfn calls that have been converted to range
> callbacks, in case they ever receieve ranges greater than 1.
> 
> Fixes: b1c5356e873c ("KVM: PPC: Convert to the gfn-based MMU notifier callbacks")
> Reported-by: Bharata B Rao <bharata@linux.ibm.com>
> Tested-by: Bharata B Rao <bharata@linux.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> The e500 change in that commit also looks suspicious, why is it okay
> to remove kvm_flush_remote_tlbs() there? Also is the the change from
> returning false to true intended?

The common code interprets a return of "true" as "do kvm_flush_remote_tlbs()".
There is technically a functional change, as the deferring the flush to common
code will batch flushes if the invalidation spans multiple memslots.  But the
mmu_lock is held the entire time, so batching is a good thing unless e500 has
wildly different MMU semantics.

^ permalink raw reply

* Re: [PATCH] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable
From: kernel test robot @ 2021-05-05 22:53 UTC (permalink / raw)
  To: Vaibhav Jain, linuxppc-dev, linux-nvdimm
  Cc: Vaibhav Jain, kbuild-all, Aneesh Kumar K . V
In-Reply-To: <20210505191708.51939-1-vaibhav@linux.ibm.com>

[-- Attachment #1: Type: text/plain, Size: 2537 bytes --]

Hi Vaibhav,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on v5.12 next-20210505]
[cannot apply to scottwood/next mpe/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Vaibhav-Jain/powerpc-papr_scm-Make-perf_stats-invisible-if-perf-stats-unavailable/20210506-031853
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/8e7ce04ec36dea95fad178585b697a9c5b5c259d
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Vaibhav-Jain/powerpc-papr_scm-Make-perf_stats-invisible-if-perf-stats-unavailable/20210506-031853
        git checkout 8e7ce04ec36dea95fad178585b697a9c5b5c259d
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> arch/powerpc/platforms/pseries/papr_scm.c:903:9: warning: no previous prototype for 'papr_nd_attribute_visible' [-Wmissing-prototypes]
     903 | umode_t papr_nd_attribute_visible(struct kobject *kobj, struct attribute *attr,
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/papr_nd_attribute_visible +903 arch/powerpc/platforms/pseries/papr_scm.c

   902	
 > 903	umode_t papr_nd_attribute_visible(struct kobject *kobj, struct attribute *attr,
   904					  int n)
   905	{
   906		struct device *dev = container_of(kobj, typeof(*dev), kobj);
   907		struct nvdimm *nvdimm = to_nvdimm(dev);
   908		struct papr_scm_priv *p = nvdimm_provider_data(nvdimm);
   909	
   910		/* For if perf-stats not available remove perf_stats sysfs */
   911		if (attr == &dev_attr_perf_stats.attr && p->stat_buffer_len == 0)
   912			return 0;
   913	
   914		return attr->mode;
   915	}
   916	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
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^ permalink raw reply

* Re: linux-next: manual merge of the akpm-current tree with the powerpc tree
From: Stephen Rothwell @ 2021-05-05 23:43 UTC (permalink / raw)
  To: Michael Ellerman, PowerPC
  Cc: Andrew Morton, Linux Next Mailing List, Linux Kernel Mailing List,
	Anshuman Khandual
In-Reply-To: <20210505113959.43340f19@canb.auug.org.au>

[-- Attachment #1: Type: text/plain, Size: 4526 bytes --]

Hi all,

On Wed, 5 May 2021 11:39:59 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Today's linux-next merge of the akpm-current tree got a conflict in:
> 
>   arch/powerpc/Kconfig
> 
> between commit:
> 
>   c6b05f4e233c ("powerpc/kconfig: Restore alphabetic order of the selects under CONFIG_PPC")
> 
> from the powerpc tree and commits:
> 
>   fd7d5c273c43 ("mm: generalize HUGETLB_PAGE_SIZE_VARIABLE")
>   301ba77ae03c ("mm: generalize ARCH_ENABLE_MEMORY_[HOTPLUG|HOTREMOVE]")
> 
> from the akpm-current tree.
> 
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
> 
> -- 
> Cheers,
> Stephen Rothwell
> 
> diff --cc arch/powerpc/Kconfig
> index ab17a56c3d10,d4333049b813..000000000000
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@@ -118,11 -118,10 +118,13 @@@ config PP
>   	# Please keep this list sorted alphabetically.
>   	#
>   	select ARCH_32BIT_OFF_T if PPC32
> + 	select ARCH_ENABLE_MEMORY_HOTPLUG
> + 	select ARCH_ENABLE_MEMORY_HOTREMOVE
>  +	select ARCH_HAS_COPY_MC			if PPC64
>   	select ARCH_HAS_DEBUG_VIRTUAL
>  +	select ARCH_HAS_DEBUG_VM_PGTABLE
>   	select ARCH_HAS_DEVMEM_IS_ALLOWED
>  +	select ARCH_HAS_DMA_MAP_DIRECT 		if PPC_PSERIES
>   	select ARCH_HAS_ELF_RANDOMIZE
>   	select ARCH_HAS_FORTIFY_SOURCE
>   	select ARCH_HAS_GCOV_PROFILE_ALL
> @@@ -163,8 -162,9 +165,8 @@@
>   	select BUILDTIME_TABLE_SORT
>   	select CLONE_BACKWARDS
>   	select DCACHE_WORD_ACCESS		if PPC64 && CPU_LITTLE_ENDIAN
> - 	select DMA_OPS_BYPASS			if PPC64
>   	select DMA_OPS				if PPC64
> + 	select DMA_OPS_BYPASS			if PPC64
>  -	select ARCH_HAS_DMA_MAP_DIRECT 		if PPC64 && PPC_PSERIES
>   	select DYNAMIC_FTRACE			if FUNCTION_TRACER
>   	select EDAC_ATOMIC_SCRUB
>   	select EDAC_SUPPORT
> @@@ -182,15 -181,12 +184,15 @@@
>   	select GENERIC_STRNCPY_FROM_USER
>   	select GENERIC_STRNLEN_USER
>   	select GENERIC_TIME_VSYSCALL
>  -	select GENERIC_GETTIMEOFDAY
>  +	select GENERIC_VDSO_TIME_NS
>   	select HAVE_ARCH_AUDITSYSCALL
> - 	select HAVE_ARCH_HUGE_VMAP		if PPC_BOOK3S_64 && PPC_RADIX_MMU
>  +	select HAVE_ARCH_HUGE_VMALLOC		if HAVE_ARCH_HUGE_VMAP
> + 	select HAVE_ARCH_HUGE_VMAP		if PPC_BOOK3S_64 && PPC_RADIX_MMU
>   	select HAVE_ARCH_JUMP_LABEL
>  +	select HAVE_ARCH_JUMP_LABEL_RELATIVE
>   	select HAVE_ARCH_KASAN			if PPC32 && PPC_PAGE_SHIFT <= 14
>   	select HAVE_ARCH_KASAN_VMALLOC		if PPC32 && PPC_PAGE_SHIFT <= 14
>  +	select HAVE_ARCH_KFENCE			if PPC32
>   	select HAVE_ARCH_KGDB
>   	select HAVE_ARCH_MMAP_RND_BITS
>   	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if COMPAT
> @@@ -231,19 -227,23 +233,20 @@@
>   	select HAVE_LIVEPATCH			if HAVE_DYNAMIC_FTRACE_WITH_REGS
>   	select HAVE_MOD_ARCH_SPECIFIC
>   	select HAVE_NMI				if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
>  -	select HAVE_HARDLOCKUP_DETECTOR_ARCH	if (PPC64 && PPC_BOOK3S)
>  -	select HAVE_OPTPROBES			if PPC64
>  +	select HAVE_OPTPROBES
>   	select HAVE_PERF_EVENTS
>   	select HAVE_PERF_EVENTS_NMI		if PPC64
>  -	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
>   	select HAVE_PERF_REGS
>   	select HAVE_PERF_USER_STACK_DUMP
>  -	select HUGETLB_PAGE_SIZE_VARIABLE	if PPC_BOOK3S_64 && HUGETLB_PAGE
>  -	select MMU_GATHER_RCU_TABLE_FREE
>  -	select MMU_GATHER_PAGE_SIZE
>   	select HAVE_REGS_AND_STACK_ACCESS_API
>  -	select HAVE_RELIABLE_STACKTRACE		if PPC_BOOK3S_64 && CPU_LITTLE_ENDIAN
>  +	select HAVE_RELIABLE_STACKTRACE
>  +	select HAVE_RSEQ
>   	select HAVE_SOFTIRQ_ON_OWN_STACK
>  +	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
>  +	select HAVE_STACKPROTECTOR		if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
>   	select HAVE_SYSCALL_TRACEPOINTS
>   	select HAVE_VIRT_CPU_ACCOUNTING
>  -	select HAVE_IRQ_TIME_ACCOUNTING
>  -	select HAVE_RSEQ
> ++	select HUGETLB_PAGE_SIZE_VARIABLE	if PPC_BOOK3S_64 && HUGETLB_PAGE
>   	select IOMMU_HELPER			if PPC64
>   	select IRQ_DOMAIN
>   	select IRQ_FORCED_THREADING

This is now a conflict between the powerpc tree and Linus' tree.

-- 
Cheers,
Stephen Rothwell

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^ permalink raw reply

* [PATCH 1/3] dt-bindings: i2c: mpc: Add fsl,i2c-erratum-a004447 flag
From: Chris Packham @ 2021-05-06  1:10 UTC (permalink / raw)
  To: wsa, andriy.shevchenko, andy.shevchenko, robh+dt, mpe
  Cc: devicetree, Chris Packham, linuxppc-dev, linux-i2c, linux-kernel
In-Reply-To: <20210506011015.17347-1-chris.packham@alliedtelesis.co.nz>

Document the fsl,i2c-erratum-a004447 flag which indicates the presence
of an i2c erratum on some QorIQ SoCs.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
 Documentation/devicetree/bindings/i2c/i2c-mpc.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml b/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml
index 7b553d559c83..98c6fcf7bf26 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml
@@ -46,6 +46,13 @@ properties:
     description: |
       I2C bus timeout in microseconds
 
+  fsl,i2c-erratum-a004447:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: |
+      Indicates the presence of QorIQ erratum A-004447, which
+      says that the standard i2c recovery scheme mechanism does
+      not work and an alternate implementation is needed.
+
 required:
   - compatible
   - reg
-- 
2.31.1


^ permalink raw reply related

* [PATCH 0/3] P2040/P2041 i2c recovery erratum
From: Chris Packham @ 2021-05-06  1:10 UTC (permalink / raw)
  To: wsa, andriy.shevchenko, andy.shevchenko, robh+dt, mpe
  Cc: devicetree, Chris Packham, linuxppc-dev, linux-i2c, linux-kernel

The P2040/P2041 has an erratum where the i2c recovery scheme
documented in the reference manual (and currently implemented
in the i2c-mpc.c driver) does not work. The errata document
provides an alternative that does work. This series implements
that alternative and uses a property in the devicetree to
decide when the alternative mechanism is needed.

Chris Packham (3):
  dt-bindings: i2c: mpc: Add fsl,i2c-erratum-a004447 flag
  powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P2041 i2c
    controllers
  i2c: mpc: implement erratum A-004447 workaround

 .../devicetree/bindings/i2c/i2c-mpc.yaml      |  7 ++
 arch/powerpc/boot/dts/fsl/p2041si-post.dtsi   | 16 ++++
 drivers/i2c/busses/i2c-mpc.c                  | 88 ++++++++++++++++++-
 3 files changed, 109 insertions(+), 2 deletions(-)

-- 
2.31.1


^ permalink raw reply

* [PATCH 3/3] i2c: mpc: implement erratum A-004447 workaround
From: Chris Packham @ 2021-05-06  1:10 UTC (permalink / raw)
  To: wsa, andriy.shevchenko, andy.shevchenko, robh+dt, mpe
  Cc: devicetree, Chris Packham, linuxppc-dev, linux-i2c, linux-kernel
In-Reply-To: <20210506011015.17347-1-chris.packham@alliedtelesis.co.nz>

The P2040/P2041 has an erratum where the normal i2c recovery mechanism
does not work. Implement the alternative recovery mechanism documented
in the P2040 Chip Errata Rev Q.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
 drivers/i2c/busses/i2c-mpc.c | 88 +++++++++++++++++++++++++++++++++++-
 1 file changed, 86 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index 30d9e89a3db2..052e37718771 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -45,6 +45,7 @@
 #define CCR_MTX  0x10
 #define CCR_TXAK 0x08
 #define CCR_RSTA 0x04
+#define CCR_RSVD 0x02
 
 #define CSR_MCF  0x80
 #define CSR_MAAS 0x40
@@ -97,7 +98,7 @@ struct mpc_i2c {
 	u32 block;
 	int rc;
 	int expect_rxack;
-
+	bool has_errata_A004447;
 };
 
 struct mpc_i2c_divider {
@@ -136,6 +137,83 @@ static void mpc_i2c_fixup(struct mpc_i2c *i2c)
 	}
 }
 
+static int i2c_mpc_wait_sr(struct mpc_i2c *i2c, int mask)
+{
+	unsigned long timeout = jiffies + usecs_to_jiffies(100);
+	int ret = 0;
+
+	while ((readb(i2c->base + MPC_I2C_SR) & mask) == 0) {
+		if (time_after(jiffies, timeout)) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+		cond_resched();
+	}
+
+	return ret;
+}
+
+/*
+ * Workaround for Erratum A004447. From the P2040CE Rev Q
+ *
+ * 1.  Set up the frequency divider and sampling rate.
+ * 2.  I2CCR - a0h
+ * 3.  Poll for I2CSR[MBB] to get set.
+ * 4.  If I2CSR[MAL] is set (an indication that SDA is stuck low), then go to
+ *     step 5. If MAL is not set, then go to step 13.
+ * 5.  I2CCR - 00h
+ * 6.  I2CCR - 22h
+ * 7.  I2CCR - a2h
+ * 8.  Poll for I2CSR[MBB] to get set.
+ * 9.  Issue read to I2CDR.
+ * 10. Poll for I2CSR[MIF] to be set.
+ * 11. I2CCR - 82h
+ * 12. Workaround complete. Skip the next steps.
+ * 13. Issue read to I2CDR.
+ * 14. Poll for I2CSR[MIF] to be set.
+ * 15. I2CCR - 80h
+ */
+static void mpc_i2c_fixup_A004447(struct mpc_i2c *i2c)
+{
+	int ret;
+	u32 val;
+
+	writeccr(i2c, CCR_MEN | CCR_MSTA);
+	ret = i2c_mpc_wait_sr(i2c, CSR_MBB);
+	if (ret) {
+		dev_err(i2c->dev, "timeout waiting for CSR_MBB\n");
+		return;
+	}
+
+	val = readb(i2c->base + MPC_I2C_SR);
+
+	if (val & CSR_MAL) {
+		writeccr(i2c, 0x00);
+		writeccr(i2c, CCR_MSTA | CCR_RSVD);
+		writeccr(i2c, CCR_MEN | CCR_MSTA | CCR_RSVD);
+		ret = i2c_mpc_wait_sr(i2c, CSR_MBB);
+		if (ret) {
+			dev_err(i2c->dev, "timeout waiting for CSR_MBB\n");
+			return;
+		}
+		val = readb(i2c->base + MPC_I2C_DR);
+		ret = i2c_mpc_wait_sr(i2c, CSR_MIF);
+		if (ret) {
+			dev_err(i2c->dev, "timeout waiting for CSR_MIF\n");
+			return;
+		}
+		writeccr(i2c, CCR_MEN | CCR_RSVD);
+	} else {
+		val = readb(i2c->base + MPC_I2C_DR);
+		ret = i2c_mpc_wait_sr(i2c, CSR_MIF);
+		if (ret) {
+			dev_err(i2c->dev, "timeout waiting for CSR_MIF\n");
+			return;
+		}
+		writeccr(i2c, CCR_MEN);
+	}
+}
+
 #if defined(CONFIG_PPC_MPC52xx) || defined(CONFIG_PPC_MPC512x)
 static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = {
 	{20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
@@ -670,7 +748,10 @@ static int fsl_i2c_bus_recovery(struct i2c_adapter *adap)
 {
 	struct mpc_i2c *i2c = i2c_get_adapdata(adap);
 
-	mpc_i2c_fixup(i2c);
+	if (i2c->has_errata_A004447)
+		mpc_i2c_fixup_A004447(i2c);
+	else
+		mpc_i2c_fixup(i2c);
 
 	return 0;
 }
@@ -767,6 +848,9 @@ static int fsl_i2c_probe(struct platform_device *op)
 	}
 	dev_info(i2c->dev, "timeout %u us\n", mpc_ops.timeout * 1000000 / HZ);
 
+	if (of_property_read_bool(op->dev.of_node, "fsl,i2c-erratum-a004447"))
+		i2c->has_errata_A004447 = true;
+
 	i2c->adap = mpc_ops;
 	scnprintf(i2c->adap.name, sizeof(i2c->adap.name),
 		  "MPC adapter (%s)", of_node_full_name(op->dev.of_node));
-- 
2.31.1


^ permalink raw reply related


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