[RFC 1/3] selftests/powerpc: Add test to check TM ucontext creation

[Cyril Bur <cyrilbur@gmail.com>]

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
---
 .../selftests/powerpc/tm/tm-signal-context-chk.c   | 102 +++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 tools/testing/selftests/powerpc/tm/tm-signal-context-chk.c

diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-context-chk.c b/tools/testing/selftests/powerpc/tm/tm-signal-context-chk.c
new file mode 100644
index 0000000..4c906cf
--- /dev/null
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-context-chk.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2016, Cyril Bur, IBM Corp.
+ * Licensed under GPLv2.
+ *
+ * Test the kernel's signal frame code.
+ *
+ * The kernel sets up two sets of ucontexts if the signal was to be delivered
+ * while the thread was in a transaction. Expected behaviour is that the
+ * currently executing code is in the first and the checkpointed state (the
+ * state that will be rolled back to) is in the uc_link ucontext.
+ *
+ * The reason for this is that code which is not TM aware and installs a signal
+ * handler will expect to see/modify its currently running state in the uc,
+ * this code may have dynamicially linked against code which is TM aware and is
+ * doing HTM under the hood.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "utils.h"
+#include "tm.h"
+
+#define TBEGIN          ".long 0x7C00051D ;"
+#define TSUSPEND        ".long 0x7C0005DD ;"
+#define TRESUME         ".long 0x7C2005DD ;"
+#define MAX_ATTEMPT 100
+
+static double fps[] = { 1, 2, 3, 4, 5, 6, 7, 8,
+						-1, -2, -3, -4, -5, -6, -7, -8 };
+
+extern long tm_signal_self(pid_t pid, double *fps);
+
+static int signaled;
+static int fail;
+
+static void signal_usr1(int signum, siginfo_t *info, void *uc)
+{
+	int i;
+	ucontext_t *ucp = uc;
+	ucontext_t *tm_ucp = ucp->uc_link;
+
+	signaled = 1;
+
+	/* Always be 64bit, don't really care about 32bit */
+	for (i = 0; i < 8 && !fail; i++) {
+		fail = (ucp->uc_mcontext.gp_regs[i + 14] != i);
+		fail |= (tm_ucp->uc_mcontext.gp_regs[i + 14] != 0xFF - i);
+	}
+	if (fail) {
+		printf("Failed on %d gpr %lu or %lu\n", i - 1, ucp->uc_mcontext.gp_regs[i + 13], tm_ucp->uc_mcontext.gp_regs[i + 13]);
+		return;
+	}
+	for (i = 0; i < 8 && !fail; i++) {
+		fail = (ucp->uc_mcontext.fp_regs[i + 14] != fps[i]);
+		fail |= (tm_ucp->uc_mcontext.fp_regs[i + 14] != fps[i + 8]);
+	}
+	if (fail) {
+		printf("Failed on %d FP %g or %g\n", i - 1, ucp->uc_mcontext.fp_regs[i + 13], tm_ucp->uc_mcontext.fp_regs[i + 13]);
+	}
+}
+
+static int tm_signal_context_chk()
+{
+	struct sigaction act;
+	int i;
+	long rc;
+	pid_t pid = getpid();
+
+	SKIP_IF(!have_htm());
+
+	act.sa_sigaction = signal_usr1;
+	sigemptyset(&act.sa_mask);
+	act.sa_flags = SA_SIGINFO;
+	if (sigaction(SIGUSR1, &act, NULL) < 0) {
+		perror("sigaction sigusr1");
+		exit(1);
+	}
+
+	i = 0;
+	while (!signaled && i < MAX_ATTEMPT) {
+		rc = tm_signal_self(pid, fps);
+		if (!rc) {
+			fprintf(stderr, "Transaction was not doomed...\n");
+			FAIL_IF(!rc);
+		}
+		i++;
+	}
+
+	if (i == MAX_ATTEMPT) {
+		fprintf(stderr, "Tried to signal %d times and didn't work, failing!\n", MAX_ATTEMPT);
+		fail = 1;
+	}
+	return fail;
+}
+
+int main(void)
+{
+	return test_harness(tm_signal_context_chk, "tm_signal_context_chk");
+}
-- 
2.9.0