[PATCH 2/2] selftests: Skip TM tests on synthetic TM implementations
Jordan Niethe
jniethe5 at gmail.com
Tue Jun 8 09:37:09 AEST 2021
Transactional Memory was removed from the architecture in ISA v3.1. For
threads running in P8/P9 compatibility mode on P10 a synthetic TM
implementation is provided. In this implementation, tbegin. always sets
cr0 eq meaning the abort handler is always called. This is not an issue
as users of TM are expected to have a fallback non transactional way to
make forward progress in the abort handler.
As the TM self tests exist only to test TM, no alternative path forward
is provided, leading to them timing out and failing on the synthetic TM
implementation.
The TEXASR indicates if a transaction failure is due to a synthetic
implementation. Check for a synthetic implementation and skip the TM
tests if so.
Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
---
.../selftests/powerpc/ptrace/ptrace-tm-gpr.c | 1 +
.../powerpc/ptrace/ptrace-tm-spd-gpr.c | 1 +
.../powerpc/ptrace/ptrace-tm-spd-tar.c | 1 +
.../selftests/powerpc/ptrace/ptrace-tm-tar.c | 1 +
.../selftests/powerpc/tm/tm-resched-dscr.c | 1 +
.../selftests/powerpc/tm/tm-signal-stack.c | 1 +
.../testing/selftests/powerpc/tm/tm-syscall.c | 2 +-
tools/testing/selftests/powerpc/tm/tm.h | 36 +++++++++++++++++++
8 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c
index 7df7100a29be..67ca297c5cca 100644
--- a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c
@@ -113,6 +113,7 @@ int ptrace_tm_gpr(void)
int ret, status;
SKIP_IF(!have_htm());
+ SKIP_IF(htm_is_synthetic());
shm_id = shmget(IPC_PRIVATE, sizeof(int) * 2, 0777|IPC_CREAT);
pid = fork();
if (pid < 0) {
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c
index 8706bea5d015..6f2bce1b6c5d 100644
--- a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c
@@ -119,6 +119,7 @@ int ptrace_tm_spd_gpr(void)
int ret, status;
SKIP_IF(!have_htm());
+ SKIP_IF(htm_is_synthetic());
shm_id = shmget(IPC_PRIVATE, sizeof(int) * 3, 0777|IPC_CREAT);
pid = fork();
if (pid < 0) {
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-tar.c b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-tar.c
index 2ecfa1158e2b..e112a34fbe59 100644
--- a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-tar.c
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-tar.c
@@ -129,6 +129,7 @@ int ptrace_tm_spd_tar(void)
int ret, status;
SKIP_IF(!have_htm());
+ SKIP_IF(htm_is_synthetic());
shm_id = shmget(IPC_PRIVATE, sizeof(int) * 3, 0777|IPC_CREAT);
pid = fork();
if (pid == 0)
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-tar.c b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-tar.c
index 46ef378a15ec..d0db6df0f0ea 100644
--- a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-tar.c
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-tar.c
@@ -117,6 +117,7 @@ int ptrace_tm_tar(void)
int ret, status;
SKIP_IF(!have_htm());
+ SKIP_IF(htm_is_synthetic());
shm_id = shmget(IPC_PRIVATE, sizeof(int) * 2, 0777|IPC_CREAT);
pid = fork();
if (pid == 0)
diff --git a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
index 4cdb83964bb3..85c940ae6ff8 100644
--- a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
+++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
@@ -40,6 +40,7 @@ int test_body(void)
uint64_t rv, dscr1 = 1, dscr2, texasr;
SKIP_IF(!have_htm());
+ SKIP_IF(htm_is_synthetic());
printf("Check DSCR TM context switch: ");
fflush(stdout);
diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-stack.c b/tools/testing/selftests/powerpc/tm/tm-signal-stack.c
index cdcf8c5bbbc7..68807aac8dd3 100644
--- a/tools/testing/selftests/powerpc/tm/tm-signal-stack.c
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-stack.c
@@ -35,6 +35,7 @@ int tm_signal_stack()
int pid;
SKIP_IF(!have_htm());
+ SKIP_IF(htm_is_synthetic());
pid = fork();
if (pid < 0)
diff --git a/tools/testing/selftests/powerpc/tm/tm-syscall.c b/tools/testing/selftests/powerpc/tm/tm-syscall.c
index becb8207b432..467a6b3134b2 100644
--- a/tools/testing/selftests/powerpc/tm/tm-syscall.c
+++ b/tools/testing/selftests/powerpc/tm/tm-syscall.c
@@ -25,7 +25,6 @@ extern int getppid_tm_suspended(void);
unsigned retries = 0;
#define TEST_DURATION 10 /* seconds */
-#define TM_RETRIES 100
pid_t getppid_tm(bool suspend)
{
@@ -67,6 +66,7 @@ int tm_syscall(void)
struct timeval end, now;
SKIP_IF(!have_htm_nosc());
+ SKIP_IF(htm_is_synthetic());
setbuf(stdout, NULL);
diff --git a/tools/testing/selftests/powerpc/tm/tm.h b/tools/testing/selftests/powerpc/tm/tm.h
index c5a1e5c163fc..c03c6e778876 100644
--- a/tools/testing/selftests/powerpc/tm/tm.h
+++ b/tools/testing/selftests/powerpc/tm/tm.h
@@ -10,6 +10,9 @@
#include <asm/tm.h>
#include "utils.h"
+#include "reg.h"
+
+#define TM_RETRIES 100
static inline bool have_htm(void)
{
@@ -31,6 +34,39 @@ static inline bool have_htm_nosc(void)
#endif
}
+/*
+ * Transactional Memory was removed in ISA 3.1. A synthetic TM implementation
+ * is provided on P10 for threads running in P8/P9 compatibility mode. The
+ * synthetic implementation immediately fails after tbegin. This failure sets
+ * Bit 7 (Failure Persistent) and Bit 15 (Implementation-specific).
+ */
+static inline bool htm_is_synthetic(void)
+{
+ int i;
+
+ /*
+ * Per the ISA, the Failure Persistent bit may be incorrect. Try a few
+ * times in case we got an Implementation-specific failure on a non ISA
+ * v3.1 system. On these systems the Implementation-specific failure
+ * should not be persistent.
+ */
+ for (i = 0; i < TM_RETRIES; i++) {
+ asm volatile(
+ "tbegin.;"
+ "beq 1f;"
+ "tend.;"
+ "1:"
+ :
+ :
+ : "memory");
+
+ if ((__builtin_get_texasr() & (TEXASR_FP | TEXASR_IC)) !=
+ (TEXASR_FP | TEXASR_IC))
+ break;
+ }
+ return i == TM_RETRIES;
+}
+
static inline long failure_code(void)
{
return __builtin_get_texasru() >> 24;
--
2.25.1
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