[PATCH] test: self: add setjmp/longjmp/initjmp test

[Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>]

We depend on sjlj for OP-TEE early loading on ARM32 as well as for
the bthread infrastructure, which powers the state machine behind the
non-blocking USB mass storage gadget implementation.

Let's add a simple test to verify everything continues to work as
expected.

Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
 test/self/Kconfig  |  5 +++
 test/self/Makefile |  1 +
 test/self/setjmp.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 104 insertions(+)
 create mode 100644 test/self/setjmp.c

diff --git a/test/self/Kconfig b/test/self/Kconfig
index d1ca6a701df3..dcbfa85896f7 100644
--- a/test/self/Kconfig
+++ b/test/self/Kconfig
@@ -40,6 +40,7 @@ config SELFTEST_ENABLE_ALL
 	imply SELFTEST_MMU
 	imply SELFTEST_REGULATOR
 	imply SELFTEST_STRING
+	imply SELFTEST_SETJMP
 	help
 	  Selects all self-tests compatible with current configuration
 
@@ -87,4 +88,8 @@ config SELFTEST_STRING
 	bool "String library selftest"
 	select VERSION_CMP
 
+config SELFTEST_SETJMP
+	bool "setjmp/longjmp library selftest"
+	depends on ARCH_HAS_SJLJ
+
 endif
diff --git a/test/self/Makefile b/test/self/Makefile
index a66f34671e5a..b6f4395147dd 100644
--- a/test/self/Makefile
+++ b/test/self/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SELFTEST_JSON) += json.o
 obj-$(CONFIG_SELFTEST_DIGEST) += digest.o
 obj-$(CONFIG_SELFTEST_MMU) += mmu.o
 obj-$(CONFIG_SELFTEST_STRING) += string.o
+obj-$(CONFIG_SELFTEST_SETJMP) += setjmp.o
 
 clean-files := *.dtb *.dtb.S .*.dtc .*.pre .*.dts *.dtb.z
 clean-files += *.dtbo *.dtbo.S .*.dtso
diff --git a/test/self/setjmp.c b/test/self/setjmp.c
new file mode 100644
index 000000000000..1cbb44bdf941
--- /dev/null
+++ b/test/self/setjmp.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: Copyright (C) 2003 Hewlett-Packard
+/*
+ * Code contributed by David Mosberger-Tang <davidm@xxxxxxxxxx>
+ * to libunwind - a platform-independent unwind library
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <common.h>
+#include <bselftest.h>
+#include <string.h>
+#include <asm/setjmp.h>
+
+BSELFTEST_GLOBALS();
+
+static __noreturn void raise_longjmp(jmp_buf jbuf, int i, int n)
+{
+	while (i < n)
+		raise_longjmp(jbuf, i + 1, n);
+
+	longjmp(jbuf, n);
+}
+
+static jmp_buf jbuf;
+
+static void __noreturn initjmp_entry(void)
+{
+	volatile u32 arr[256];
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(arr); i++)
+		writel(i, &arr[i]);
+
+	/* ensure arr[] is allocated on stack */
+	OPTIMIZER_HIDE_VAR(i);
+	if (i == 0)
+		initjmp_entry();
+
+	longjmp(jbuf, 0x1337);
+}
+
+static void test_setjmp(void)
+{
+	void *stack;
+	jmp_buf ijbuf;
+	volatile int i;
+	int ret;
+
+	total_tests += 20;
+
+	for (i = 0; i < 10; ++i) {
+		if ((ret = setjmp(jbuf))) {
+			pr_debug("%s: secondary setjmp() return, ret=%d\n",
+				 __func__, ret);
+
+			if (ret != i + 1) {
+				printf("%s: setjmp() returned %d, expected %d\n",
+					 __func__, ret, i + 1);
+				failed_tests += 2;
+			}
+			continue;
+		}
+
+		pr_debug("%s.%d: done with setjmp(); calling children\n",
+			 __func__, i + 1);
+
+		raise_longjmp(jbuf, 0, i + 1);
+
+		printf("%s: raise_longjmp() returned unexpectedly\n", __func__);
+		failed_tests++;
+	}
+
+	stack = memalign(16, CONFIG_STACK_SIZE);
+	if (WARN_ON(!stack)) {
+		skipped_tests++;
+		return;
+	}
+
+	pr_debug("%s: testing initjmp\n", __func__);
+
+	total_tests += 1;
+
+	/* initialize new context with fresh stack */
+	initjmp(ijbuf, initjmp_entry, stack + CONFIG_STACK_SIZE);
+
+	switch (setjmp(jbuf)) {
+	case 0x1337:
+		break;
+	case 0:
+		longjmp(ijbuf, 0x42);
+	default:
+		failed_tests++;
+	}
+
+	free(stack);
+}
+bselftest(core, test_setjmp);
-- 
2.39.2