[PATCH AUTOSEL 4.14 02/16] powerpc/6xx: add missing of_node_put

[PATCH AUTOSEL 4.14 02/16] powerpc/6xx: add missing of_node_put

[Sasha Levin]

From: Julia Lawall <Julia.Lawall@lip6.fr>

[ Upstream commit f6e82647ff71d427d4148964b71f239fba9d7937 ]

for_each_compatible_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression e;
local idexpression n;
@@

@@
local idexpression n;
expression e;
@@

 for_each_compatible_node(n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  break;
)
   ...
 }
... when != n
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-2-git-send-email-Julia.Lawall@lip6.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/embedded6xx/hlwd-pic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/platforms/embedded6xx/hlwd-pic.c b/arch/powerpc/platforms/embedded6xx/hlwd-pic.c
index bf4a125faec66..db2ea6b6889de 100644
--- a/arch/powerpc/platforms/embedded6xx/hlwd-pic.c
+++ b/arch/powerpc/platforms/embedded6xx/hlwd-pic.c
@@ -220,6 +220,7 @@ void hlwd_pic_probe(void)
 			irq_set_chained_handler(cascade_virq,
 						hlwd_pic_irq_cascade);
 			hlwd_irq_host = host;
+			of_node_put(np);
 			break;
 		}
 	}
-- 
2.34.1

[PATCH AUTOSEL 4.14 03/16] powerpc/powernv: add missing of_node_put

[Sasha Levin]

From: Julia Lawall <Julia.Lawall@lip6.fr>

[ Upstream commit 7d405a939ca960162eb30c1475759cb2fdf38f8c ]

for_each_compatible_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
local idexpression n;
expression e;
@@

 for_each_compatible_node(n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  break;
)
   ...
 }
... when != n
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-4-git-send-email-Julia.Lawall@lip6.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/powernv/opal-lpc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/platforms/powernv/opal-lpc.c b/arch/powerpc/platforms/powernv/opal-lpc.c
index 6c7ad1d8b32ed..21f0edcfb84ad 100644
--- a/arch/powerpc/platforms/powernv/opal-lpc.c
+++ b/arch/powerpc/platforms/powernv/opal-lpc.c
@@ -400,6 +400,7 @@ void __init opal_lpc_init(void)
 		if (!of_get_property(np, "primary", NULL))
 			continue;
 		opal_lpc_chip_id = of_get_ibm_chip_id(np);
+		of_node_put(np);
 		break;
 	}
 	if (opal_lpc_chip_id < 0)
-- 
2.34.1

[PATCH AUTOSEL 4.14 04/16] powerpc/cell: add missing of_node_put

[Sasha Levin]

From: Julia Lawall <Julia.Lawall@lip6.fr>

[ Upstream commit a841fd009e51c8c0a8f07c942e9ab6bb48da8858 ]

for_each_node_by_name performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression e,e1;
local idexpression n;
@@

 for_each_node_by_name(n, e1) {
   ... when != of_node_put(n)
       when != e = n
(
   return n;
|
+  of_node_put(n);
?  return ...;
)
   ...
 }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-7-git-send-email-Julia.Lawall@lip6.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/cell/iommu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index 4b91ad08eefd9..c4f352387aec3 100644
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -1088,6 +1088,7 @@ static int __init cell_iommu_fixed_mapping_init(void)
 			if (hbase < dbase || (hend > (dbase + dsize))) {
 				pr_debug("iommu: hash window doesn't fit in"
 					 "real DMA window\n");
+				of_node_put(np);
 				return -1;
 			}
 		}
-- 
2.34.1

[PATCH AUTOSEL 4.14 05/16] powerpc/btext: add missing of_node_put

[Sasha Levin]

From: Julia Lawall <Julia.Lawall@lip6.fr>

[ Upstream commit a1d2b210ffa52d60acabbf7b6af3ef7e1e69cda0 ]

for_each_node_by_type performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
local idexpression n;
expression e;
@@

 for_each_node_by_type(n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  break;
)
   ...
 }
... when != n
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-6-git-send-email-Julia.Lawall@lip6.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/btext.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/btext.c b/arch/powerpc/kernel/btext.c
index 6537cba1a7580..d1a2fc7186ce7 100644
--- a/arch/powerpc/kernel/btext.c
+++ b/arch/powerpc/kernel/btext.c
@@ -258,8 +258,10 @@ int __init btext_find_display(int allow_nonstdout)
 			rc = btext_initialize(np);
 			printk("result: %d\n", rc);
 		}
-		if (rc == 0)
+		if (rc == 0) {
+			of_node_put(np);
 			break;
+		}
 	}
 	return rc;
 }
-- 
2.34.1

[PATCH AUTOSEL 4.14 06/16] powerpc/watchdog: Fix missed watchdog reset due to memory ordering race

[Sasha Levin]

From: Nicholas Piggin <npiggin@gmail.com>

[ Upstream commit 5dad4ba68a2483fc80d70b9dc90bbe16e1f27263 ]

It is possible for all CPUs to miss the pending cpumask becoming clear,
and then nobody resetting it, which will cause the lockup detector to
stop working. It will eventually expire, but watchdog_smp_panic will
avoid doing anything if the pending mask is clear and it will never be
reset.

Order the cpumask clear vs the subsequent test to close this race.

Add an extra check for an empty pending mask when the watchdog fires and
finds its bit still clear, to try to catch any other possible races or
bugs here and keep the watchdog working. The extra test in
arch_touch_nmi_watchdog is required to prevent the new warning from
firing off.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Debugged-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211110025056.2084347-2-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/watchdog.c | 41 +++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index ce848ff84eddf..1617767ebc9ae 100644
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c
@@ -106,6 +106,10 @@ static void set_cpumask_stuck(const struct cpumask *cpumask, u64 tb)
 {
 	cpumask_or(&wd_smp_cpus_stuck, &wd_smp_cpus_stuck, cpumask);
 	cpumask_andnot(&wd_smp_cpus_pending, &wd_smp_cpus_pending, cpumask);
+	/*
+	 * See wd_smp_clear_cpu_pending()
+	 */
+	smp_mb();
 	if (cpumask_empty(&wd_smp_cpus_pending)) {
 		wd_smp_last_reset_tb = tb;
 		cpumask_andnot(&wd_smp_cpus_pending,
@@ -177,13 +181,44 @@ static void wd_smp_clear_cpu_pending(int cpu, u64 tb)
 			wd_smp_lock(&flags);
 			cpumask_clear_cpu(cpu, &wd_smp_cpus_stuck);
 			wd_smp_unlock(&flags);
+		} else {
+			/*
+			 * The last CPU to clear pending should have reset the
+			 * watchdog so we generally should not find it empty
+			 * here if our CPU was clear. However it could happen
+			 * due to a rare race with another CPU taking the
+			 * last CPU out of the mask concurrently.
+			 *
+			 * We can't add a warning for it. But just in case
+			 * there is a problem with the watchdog that is causing
+			 * the mask to not be reset, try to kick it along here.
+			 */
+			if (unlikely(cpumask_empty(&wd_smp_cpus_pending)))
+				goto none_pending;
 		}
 		return;
 	}
+
 	cpumask_clear_cpu(cpu, &wd_smp_cpus_pending);
+
+	/*
+	 * Order the store to clear pending with the load(s) to check all
+	 * words in the pending mask to check they are all empty. This orders
+	 * with the same barrier on another CPU. This prevents two CPUs
+	 * clearing the last 2 pending bits, but neither seeing the other's
+	 * store when checking if the mask is empty, and missing an empty
+	 * mask, which ends with a false positive.
+	 */
+	smp_mb();
 	if (cpumask_empty(&wd_smp_cpus_pending)) {
 		unsigned long flags;
 
+none_pending:
+		/*
+		 * Double check under lock because more than one CPU could see
+		 * a clear mask with the lockless check after clearing their
+		 * pending bits.
+		 */
 		wd_smp_lock(&flags);
 		if (cpumask_empty(&wd_smp_cpus_pending)) {
 			wd_smp_last_reset_tb = tb;
@@ -276,8 +311,12 @@ void arch_touch_nmi_watchdog(void)
 {
 	unsigned long ticks = tb_ticks_per_usec * wd_timer_period_ms * 1000;
 	int cpu = smp_processor_id();
-	u64 tb = get_tb();
+	u64 tb;
+
+	if (!cpumask_test_cpu(cpu, &watchdog_cpumask))
+		return;
 
+	tb = get_tb();
 	if (tb - per_cpu(wd_timer_tb, cpu) >= ticks) {
 		per_cpu(wd_timer_tb, cpu) = tb;
 		wd_smp_clear_cpu_pending(cpu, tb);
-- 
2.34.1

[PATCH AUTOSEL 4.14 08/16] powerpc/smp: Move setup_profiling_timer() under CONFIG_PROFILING

[Sasha Levin]

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

[ Upstream commit a4ac0d249a5db80e79d573db9e4ad29354b643a8 ]

setup_profiling_timer() is only needed when CONFIG_PROFILING is enabled.

Fixes the following W=1 warning when CONFIG_PROFILING=n:
  linux/arch/powerpc/kernel/smp.c:1638:5: error: no previous prototype for ‘setup_profiling_timer’

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211124093254.1054750-5-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/smp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 7c7aa7c98ba31..cf25b95ceee13 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1009,10 +1009,12 @@ void start_secondary(void *unused)
 	BUG();
 }
 
+#ifdef CONFIG_PROFILING
 int setup_profiling_timer(unsigned int multiplier)
 {
 	return 0;
 }
+#endif
 
 #ifdef CONFIG_SCHED_SMT
 /* cpumask of CPUs with asymetric SMT dependancy */
-- 
2.34.1