Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 180 insertions, 0 deletions

diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c b/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c
new file mode 100644
index 000000000..421cb082f
--- /dev/null
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018, Breno Leitao, Gustavo Romero, IBM Corp.
+ *
+ * This test raises a SIGUSR1 signal, and toggle the MSR[TS]
+ * fields at the signal handler. With MSR[TS] being set, the kernel will
+ * force a recheckpoint, which may cause a segfault when returning to
+ * user space. Since the test needs to re-run, the segfault needs to be
+ * caught and handled.
+ *
+ * In order to continue the test even after a segfault, the context is
+ * saved prior to the signal being raised, and it is restored when there is
+ * a segmentation fault. This happens for COUNT_MAX times.
+ *
+ * This test never fails (as returning EXIT_FAILURE). It either succeeds,
+ * or crash the kernel (on a buggy kernel).
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <ucontext.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include "tm.h"
+#include "utils.h"
+#include "reg.h"
+
+#define COUNT_MAX       5000		/* Number of interactions */
+
+/*
+ * This test only runs on 64 bits system. Unsetting MSR_TS_S to avoid
+ * compilation issue on 32 bits system. There is no side effect, since the
+ * whole test will be skipped if it is not running on 64 bits system.
+ */
+#ifndef __powerpc64__
+#undef  MSR_TS_S
+#define MSR_TS_S	0
+#endif
+
+/* Setting contexts because the test will crash and we want to recover */
+ucontext_t init_context;
+
+/* count is changed in the signal handler, so it must be volatile */
+static volatile int count;
+
+void usr_signal_handler(int signo, siginfo_t *si, void *uc)
+{
+	ucontext_t *ucp = uc;
+	int ret;
+
+	/*
+	 * Allocating memory in a signal handler, and never freeing it on
+	 * purpose, forcing the heap increase, so, the memory leak is what
+	 * we want here.
+	 */
+	ucp->uc_link = mmap(NULL, sizeof(ucontext_t),
+			    PROT_READ | PROT_WRITE,
+			    MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+	if (ucp->uc_link == (void *)-1) {
+		perror("Mmap failed");
+		exit(-1);
+	}
+
+	/* Forcing the page to be allocated in a page fault */
+	ret = madvise(ucp->uc_link, sizeof(ucontext_t), MADV_DONTNEED);
+	if (ret) {
+		perror("madvise failed");
+		exit(-1);
+	}
+
+	memcpy(&ucp->uc_link->uc_mcontext, &ucp->uc_mcontext,
+		sizeof(ucp->uc_mcontext));
+
+	/* Forcing to enable MSR[TM] */
+	UCONTEXT_MSR(ucp) |= MSR_TS_S;
+
+	/*
+	 * A fork inside a signal handler seems to be more efficient than a
+	 * fork() prior to the signal being raised.
+	 */
+	if (fork() == 0) {
+		/*
+		 * Both child and parent will return, but, child returns
+		 * with count set so it will exit in the next segfault.
+		 * Parent will continue to loop.
+		 */
+		count = COUNT_MAX;
+	}
+
+	/*
+	 * If the change above does not hit the bug, it will cause a
+	 * segmentation fault, since the ck structures are NULL.
+	 */
+}
+
+void seg_signal_handler(int signo, siginfo_t *si, void *uc)
+{
+	count++;
+
+	/* Reexecute the test */
+	setcontext(&init_context);
+}
+
+void tm_trap_test(void)
+{
+	struct sigaction usr_sa, seg_sa;
+	stack_t ss;
+
+	usr_sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
+	usr_sa.sa_sigaction = usr_signal_handler;
+
+	seg_sa.sa_flags = SA_SIGINFO;
+	seg_sa.sa_sigaction = seg_signal_handler;
+
+	/*
+	 * Set initial context. Will get back here from
+	 * seg_signal_handler()
+	 */
+	getcontext(&init_context);
+
+	while (count < COUNT_MAX) {
+		/* Allocated an alternative signal stack area */
+		ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
+				MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+		ss.ss_size = SIGSTKSZ;
+		ss.ss_flags = 0;
+
+		if (ss.ss_sp == (void *)-1) {
+			perror("mmap error\n");
+			exit(-1);
+		}
+
+		/* Force the allocation through a page fault */
+		if (madvise(ss.ss_sp, SIGSTKSZ, MADV_DONTNEED)) {
+			perror("madvise\n");
+			exit(-1);
+		}
+
+		/*
+		 * Setting an alternative stack to generate a page fault when
+		 * the signal is raised.
+		 */
+		if (sigaltstack(&ss, NULL)) {
+			perror("sigaltstack\n");
+			exit(-1);
+		}
+
+		/* The signal handler will enable MSR_TS */
+		sigaction(SIGUSR1, &usr_sa, NULL);
+		/* If it does not crash, it might segfault, avoid it to retest */
+		sigaction(SIGSEGV, &seg_sa, NULL);
+
+		raise(SIGUSR1);
+		count++;
+	}
+}
+
+int tm_signal_context_force_tm(void)
+{
+	SKIP_IF(!have_htm());
+	/*
+	 * Skipping if not running on 64 bits system, since I think it is
+	 * not possible to set mcontext's [MSR] with TS, due to it being 32
+	 * bits.
+	 */
+	SKIP_IF(!is_ppc64le());
+
+	tm_trap_test();
+
+	return EXIT_SUCCESS;
+}
+
+int main(int argc, char **argv)
+{
+	test_harness(tm_signal_context_force_tm, "tm_signal_context_force_tm");
+}