[PATCH] selftest/powerpc: Add test for sigreturn in transaction

[Laurent Dufour <ldufour@linux.vnet.ibm.com>]

Ensure that kernel is throwing away the suspended transaction when
sigreturn() is called otherwise it if fails to restore the signal
frame's TM SPRS.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
 tools/testing/selftests/powerpc/tm/Makefile       |  2 +-
 tools/testing/selftests/powerpc/tm/tm-sigreturn.c | 89 +++++++++++++++++++++++
 2 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/powerpc/tm/tm-sigreturn.c

diff --git a/tools/testing/selftests/powerpc/tm/Makefile b/tools/testing/selftests/powerpc/tm/Makefile
index 9d301d785d9e..5e0396d79c8a 100644
--- a/tools/testing/selftests/powerpc/tm/Makefile
+++ b/tools/testing/selftests/powerpc/tm/Makefile
@@ -1,5 +1,5 @@
 TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack \
-	tm-vmxcopy tm-fork tm-tar tm-tmspr tm-exec tm-execed
+	tm-vmxcopy tm-fork tm-tar tm-tmspr tm-exec tm-execed tm-sigreturn
 
 all: $(TEST_PROGS)
 
diff --git a/tools/testing/selftests/powerpc/tm/tm-sigreturn.c b/tools/testing/selftests/powerpc/tm/tm-sigreturn.c
new file mode 100644
index 000000000000..43fa83de23a5
--- /dev/null
+++ b/tools/testing/selftests/powerpc/tm/tm-sigreturn.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2015, Laurent Dufour, IBM Corp.
+ * Licensed under GPLv2.
+ *
+ * Test the kernel's signal returning code to check reclaim is done if
+ * the sigreturn() is called while in a transaction (suspended since active
+ * is already dropped trough the system call path).
+ *
+ * The kernel must discard the transaction when entering sigreturn,
+ * since restoring the potential TM SPRS from the signal frame is requiring to
+ * not be in a transaction.
+ */
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <signal.h>
+#include <string.h>
+
+#include "utils.h"
+#include "tm.h"
+
+
+void handler(int sig)
+{
+	uint64_t ret;
+
+	asm __volatile__(
+		"li             3,1             ;"
+		"tbegin.                        ;"
+		"beq            1f              ;"
+		"li             3,0             ;"
+		"tsuspend.                      ;"
+		"1:                             ;"
+		"std%X[ret]     3, %[ret]       ;"
+		: [ret]"=m"(ret)
+		:
+		: "memory", "3", "cr0");
+
+	if (ret)
+		exit(1);
+
+	/*
+	 * We return from the signal handle while in a suspended transaction
+	 */
+}
+
+
+int tm_sigreturn(void)
+{
+	struct sigaction sa;
+	uint64_t ret = 0;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = handler;
+	sigemptyset(&sa.sa_mask);
+
+	if (sigaction(SIGSEGV, &sa, NULL))
+		exit(1);
+
+	asm __volatile__(
+		"tbegin.                        ;"
+		"beq            1f              ;"
+		"li             3,0             ;"
+		"std            3,0(3)          ;" /* trigger SEGV */
+		"li             3,1             ;"
+		"std%X[ret]     3,%[ret]        ;"
+		"tend.                          ;"
+		"b              2f              ;"
+		"1:                             ;"
+		"li             3,2             ;"
+		"std%X[ret]     3,%[ret]        ;"
+		"2:                             ;"
+		: [ret]"=m"(ret)
+		:
+		: "memory", "3", "cr0");
+
+	if (ret != 2)
+		exit(1);
+
+	exit(0);
+}
+
+int main(void)
+{
+	return test_harness(tm_sigreturn, "tm_sigreturn");
+}
-- 
2.7.4