[PATCH AUTOSEL 4.19 02/16] s390/facility: Disable compile time optimization for decompressor code

[PATCH AUTOSEL 4.19 02/16] s390/facility: Disable compile time optimization for decompressor code

[Sasha Levin]

From: Heiko Carstens <hca@linux.ibm.com>

[ Upstream commit 0147addc4fb72a39448b8873d8acdf3a0f29aa65 ]

Disable compile time optimizations of test_facility() for the
decompressor. The decompressor should not contain any optimized code
depending on the architecture level set the kernel image is compiled
for to avoid unexpected operation exceptions.

Add a __DECOMPRESSOR check to test_facility() to enforce that
facilities are always checked during runtime for the decompressor.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/include/asm/facility.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/s390/include/asm/facility.h b/arch/s390/include/asm/facility.h
index 7ffbc5d7ccf38..79730031e17f3 100644
--- a/arch/s390/include/asm/facility.h
+++ b/arch/s390/include/asm/facility.h
@@ -53,8 +53,10 @@ static inline int test_facility(unsigned long nr)
 	unsigned long facilities_als[] = { FACILITIES_ALS };
 
 	if (__builtin_constant_p(nr) && nr < sizeof(facilities_als) * 8) {
-		if (__test_facility(nr, &facilities_als))
-			return 1;
+		if (__test_facility(nr, &facilities_als)) {
+			if (!__is_defined(__DECOMPRESSOR))
+				return 1;
+		}
 	}
 	return __test_facility(nr, &S390_lowcore.stfle_fac_list);
 }
-- 
2.43.0

[PATCH AUTOSEL 4.19 03/16] s390/mm: Add cond_resched() to cmm_alloc/free_pages()

[Sasha Levin]

From: Gerald Schaefer <gerald.schaefer@linux.ibm.com>

[ Upstream commit 131b8db78558120f58c5dc745ea9655f6b854162 ]

Adding/removing large amount of pages at once to/from the CMM balloon
can result in rcu_sched stalls or workqueue lockups, because of busy
looping w/o cond_resched().

Prevent this by adding a cond_resched(). cmm_free_pages() holds a
spin_lock while looping, so it cannot be added directly to the existing
loop. Instead, introduce a wrapper function that operates on maximum 256
pages at once, and add it there.

Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/mm/cmm.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c
index a51c892f14f3e..756aefbd05249 100644
--- a/arch/s390/mm/cmm.c
+++ b/arch/s390/mm/cmm.c
@@ -98,11 +98,12 @@ static long cmm_alloc_pages(long nr, long *counter,
 		(*counter)++;
 		spin_unlock(&cmm_lock);
 		nr--;
+		cond_resched();
 	}
 	return nr;
 }
 
-static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
+static long __cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 {
 	struct cmm_page_array *pa;
 	unsigned long addr;
@@ -126,6 +127,21 @@ static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 	return nr;
 }
 
+static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
+{
+	long inc = 0;
+
+	while (nr) {
+		inc = min(256L, nr);
+		nr -= inc;
+		inc = __cmm_free_pages(inc, counter, list);
+		if (inc)
+			break;
+		cond_resched();
+	}
+	return nr + inc;
+}
+
 static int cmm_oom_notify(struct notifier_block *self,
 			  unsigned long dummy, void *parm)
 {
-- 
2.43.0

[PATCH AUTOSEL 4.19 07/16] s390/cpum_sf: Remove WARN_ON_ONCE statements

[Sasha Levin]

From: Thomas Richter <tmricht@linux.ibm.com>

[ Upstream commit b495e710157606889f2d8bdc62aebf2aa02f67a7 ]

Remove WARN_ON_ONCE statements. These have not triggered in the
past.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/kernel/perf_cpum_sf.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index c8e1e325215b8..c7f94b5d93968 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1360,7 +1360,7 @@ static int aux_output_begin(struct perf_output_handle *handle,
 	unsigned long head, base, offset;
 	struct hws_trailer_entry *te;
 
-	if (WARN_ON_ONCE(handle->head & ~PAGE_MASK))
+	if (handle->head & ~PAGE_MASK)
 		return -EINVAL;
 
 	aux->head = handle->head >> PAGE_SHIFT;
@@ -1528,7 +1528,7 @@ static void hw_collect_aux(struct cpu_hw_sf *cpuhw)
 	unsigned long num_sdb;
 
 	aux = perf_get_aux(handle);
-	if (WARN_ON_ONCE(!aux))
+	if (!aux)
 		return;
 
 	/* Inform user space new data arrived */
@@ -1547,7 +1547,7 @@ static void hw_collect_aux(struct cpu_hw_sf *cpuhw)
 			debug_sprintf_event(sfdbg, 1, "AUX buffer used up\n");
 			break;
 		}
-		if (WARN_ON_ONCE(!aux))
+		if (!aux)
 			return;
 
 		/* Update head and alert_mark to new position */
@@ -1746,12 +1746,8 @@ static void cpumsf_pmu_start(struct perf_event *event, int flags)
 {
 	struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf);
 
-	if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
+	if (!(event->hw.state & PERF_HES_STOPPED))
 		return;
-
-	if (flags & PERF_EF_RELOAD)
-		WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
-
 	perf_pmu_disable(event->pmu);
 	event->hw.state = 0;
 	cpuhw->lsctl.cs = 1;
-- 
2.43.0