[PATCH] selftests/powerpc: Do not fail on TM_CAUSE_RESCHED

[Breno Leitao]

There are cases where the test is not expecting to have the transaction
aborted, but, the test process might have been rescheduled, either in the OS
level or by KVM (if it is running on a KVM guest machine). The process
reschedule will cause a treclaim/recheckpoint which will cause the transaction
to doom, failing as soon as the process is rescheduled back to the CPU. This
might cause the test to fail, but this is not a failure in essence.

If that is the case, TEXASR[FC] is indicated with either
TM_CAUSE_RESCHEDULE or TM_CAUSE_KVM_RESCHEDULE for KVM interruptions.

In this scenario, ignore these two failures and avoid the whole test to return
failure.

CC: Gustavo Romero <gromero at linux.vnet.ibm.com>
Signed-off-by: Breno Leitao <leitao at debian.org>
---
 tools/testing/selftests/powerpc/tm/tm-unavailable.c | 10 +++++++---
 tools/testing/selftests/powerpc/tm/tm.h             |  9 +++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/powerpc/tm/tm-unavailable.c b/tools/testing/selftests/powerpc/tm/tm-unavailable.c
index 156c8e750259..0fd793f574c3 100644
--- a/tools/testing/selftests/powerpc/tm/tm-unavailable.c
+++ b/tools/testing/selftests/powerpc/tm/tm-unavailable.c
@@ -236,7 +236,8 @@ void *tm_una_ping(void *input)
 	}
 
 	/* Check if we were not expecting a failure and a it occurred. */
-	if (!expecting_failure() && is_failure(cr_)) {
+	if (!expecting_failure() && is_failure(cr_) &&
+	    !failure_is_reschedule()) {
 		printf("\n\tUnexpected transaction failure 0x%02lx\n\t",
 			failure_code());
 		return (void *) -1;
@@ -244,9 +245,12 @@ void *tm_una_ping(void *input)
 
 	/*
 	 * Check if TM failed due to the cause we were expecting. 0xda is a
-	 * TM_CAUSE_FAC_UNAV cause, otherwise it's an unexpected cause.
+	 * TM_CAUSE_FAC_UNAV cause, otherwise it's an unexpected cause, unless
+	 * it was caused by a reschedule.
 	 */
-	if (is_failure(cr_) && !failure_is_unavailable()) {
+
+	if (is_failure(cr_) && !failure_is_unavailable()
+	    & !failure_is_reschedule()) {
 		printf("\n\tUnexpected failure cause 0x%02lx\n\t",
 			failure_code());
 		return (void *) -1;
diff --git a/tools/testing/selftests/powerpc/tm/tm.h b/tools/testing/selftests/powerpc/tm/tm.h
index df4204247d45..5518b1d4ef8b 100644
--- a/tools/testing/selftests/powerpc/tm/tm.h
+++ b/tools/testing/selftests/powerpc/tm/tm.h
@@ -52,6 +52,15 @@ static inline bool failure_is_unavailable(void)
 	return (failure_code() & TM_CAUSE_FAC_UNAV) == TM_CAUSE_FAC_UNAV;
 }
 
+static inline bool failure_is_reschedule(void)
+{
+	if ((failure_code() & TM_CAUSE_RESCHED) == TM_CAUSE_RESCHED ||
+	    (failure_code() & TM_CAUSE_KVM_RESCHED) == TM_CAUSE_KVM_RESCHED)
+		return true;
+
+	return false;
+}
+
 static inline bool failure_is_nesting(void)
 {
 	return (__builtin_get_texasru() & 0x400000);
-- 
2.16.3