[PATCH 4/4] selftests/powerpc: Add checks for transactional sigreturn

[Breno Leitao <leitao@debian.org>]

This is a new test case that creates a signal and starts a suspended
transaction inside the signal handler.

It returns from the signal handler with the CPU at suspended state, but
without setting user context MSR Transaction State (TS) field.

The kernel signal handler code should be able to handle this discrepancy
instead of crashing.

This code could be compiled and used to test 32 and 64-bits signal
handlers.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com>
---
 tools/testing/selftests/powerpc/tm/.gitignore |  1 +
 tools/testing/selftests/powerpc/tm/Makefile   |  2 +-
 .../powerpc/tm/tm-signal-sigreturn-nt.c       | 46 +++++++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/powerpc/tm/tm-signal-sigreturn-nt.c

diff --git a/tools/testing/selftests/powerpc/tm/.gitignore b/tools/testing/selftests/powerpc/tm/.gitignore
index c3ee8393dae8..208452a93e2c 100644
--- a/tools/testing/selftests/powerpc/tm/.gitignore
+++ b/tools/testing/selftests/powerpc/tm/.gitignore
@@ -11,6 +11,7 @@ tm-signal-context-chk-fpu
 tm-signal-context-chk-gpr
 tm-signal-context-chk-vmx
 tm-signal-context-chk-vsx
+tm-signal-sigreturn-nt
 tm-vmx-unavail
 tm-unavailable
 tm-trap
diff --git a/tools/testing/selftests/powerpc/tm/Makefile b/tools/testing/selftests/powerpc/tm/Makefile
index 9fc2cf6fbc92..75a685359129 100644
--- a/tools/testing/selftests/powerpc/tm/Makefile
+++ b/tools/testing/selftests/powerpc/tm/Makefile
@@ -4,7 +4,7 @@ SIGNAL_CONTEXT_CHK_TESTS := tm-signal-context-chk-gpr tm-signal-context-chk-fpu
 
 TEST_GEN_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack \
 	tm-vmxcopy tm-fork tm-tar tm-tmspr tm-vmx-unavail tm-unavailable tm-trap \
-	$(SIGNAL_CONTEXT_CHK_TESTS) tm-sigreturn
+	$(SIGNAL_CONTEXT_CHK_TESTS) tm-sigreturn tm-signal-sigreturn-nt
 
 top_srcdir = ../../../../..
 include ../../lib.mk
diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-sigreturn-nt.c b/tools/testing/selftests/powerpc/tm/tm-signal-sigreturn-nt.c
new file mode 100644
index 000000000000..56fbf9f6bbf3
--- /dev/null
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-sigreturn-nt.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018, Breno Leitao, Gustavo Romero, IBM Corp.
+ *
+ * A test case that creates a signal and starts a suspended transaction
+ * inside the signal handler.
+ *
+ * It returns from the signal handler with the CPU at suspended state, but
+ * without setting usercontext MSR Transaction State (TS) fields.
+ */
+
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <signal.h>
+
+#include "utils.h"
+
+void trap_signal_handler(int signo, siginfo_t *si, void *uc)
+{
+	ucontext_t *ucp = (ucontext_t *) uc;
+
+	asm("tbegin.; tsuspend.;");
+
+	/* Skip 'trap' instruction if it succeed */
+	ucp->uc_mcontext.regs->nip += 4;
+}
+
+int tm_signal_sigreturn_nt(void)
+{
+	struct sigaction trap_sa;
+
+	trap_sa.sa_flags = SA_SIGINFO;
+	trap_sa.sa_sigaction = trap_signal_handler;
+
+	sigaction(SIGTRAP, &trap_sa, NULL);
+
+	raise(SIGTRAP);
+
+	return EXIT_SUCCESS;
+}
+
+int main(int argc, char **argv)
+{
+	test_harness(tm_signal_sigreturn_nt, "tm_signal_sigreturn_nt");
+}
+
-- 
2.19.0