[PATCH v4 0/2] riscv: simplify longjmp

[PATCH v4 0/2] riscv: simplify longjmp

[Heinrich Schuchardt]

The implementation of longjmp() is simplified.
A unit test for longjmp() is provided.

For testing use

    CONFIG_UNIT_TEST=y
    CONFIG_CMD_SETEXPR=n

and execute

    ut lib

v4:
	in unit test use volatile for variable changed between setjmp and
	longjmp
v3:
	improve unit test
v2:
	correct title of patch 1

Heinrich Schuchardt (2):
  riscv: simplify longjmp
  test: unit test for longjmp

 arch/riscv/lib/setjmp.S |  8 ++---
 test/lib/Makefile       |  1 +
 test/lib/longjmp.c      | 73 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 6 deletions(-)
 create mode 100644 test/lib/longjmp.c

--
2.30.2

[PATCH v4 1/2] riscv: simplify longjmp

[Heinrich Schuchardt]

The value returned by setjmp must be nonzero. If zero is passed as
parameter it must be replaced by 1.

This patch reduces the code size a bit.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
---
v4:
	no change
v3:
	no change
v2:
	correct typo in title
---
 arch/riscv/lib/setjmp.S | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/lib/setjmp.S b/arch/riscv/lib/setjmp.S
index 72bc9241f6..99d6195827 100644
--- a/arch/riscv/lib/setjmp.S
+++ b/arch/riscv/lib/setjmp.S
@@ -54,12 +54,8 @@ ENTRY(longjmp)
 	LOAD_IDX(sp, 13)

 	/* Move the return value in place, but return 1 if passed 0. */
-	beq a1, zero, longjmp_1
-	mv a0, a1
-	ret
-
-	longjmp_1:
-	li a0, 1
+	seqz a0, a1
+	add a0, a0, a1
 	ret
 ENDPROC(longjmp)
 .popsection
--
2.30.2

[PATCH v4 2/2] test: unit test for longjmp

[Heinrich Schuchardt]

Provide a unit test for the longjmp() library function

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
----
v4:
	use volatile for variable changed between setjmp and longjmp
v3:
	check variable on stack
v2:
	no change
---
 test/lib/Makefile  |  1 +
 test/lib/longjmp.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)
 create mode 100644 test/lib/longjmp.c

diff --git a/test/lib/Makefile b/test/lib/Makefile
index 97c11e35a8..a30f615aa9 100644
--- a/test/lib/Makefile
+++ b/test/lib/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_EFI_LOADER) += efi_device_path.o
 obj-$(CONFIG_EFI_SECURE_BOOT) += efi_image_region.o
 obj-y += hexdump.o
 obj-y += lmb.o
+obj-y += longjmp.o
 obj-$(CONFIG_CONSOLE_RECORD) += test_print.o
 obj-$(CONFIG_SSCANF) += sscanf.o
 obj-y += string.o
diff --git a/test/lib/longjmp.c b/test/lib/longjmp.c
new file mode 100644
index 0000000000..bd1fe1aff6
--- /dev/null
+++ b/test/lib/longjmp.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Test setjmp(), longjmp()
+ *
+ * Copyright (c) 2021, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ */
+
+#include <common.h>
+#include <test/lib.h>
+#include <test/test.h>
+#include <test/ut.h>
+#include <asm/setjmp.h>
+
+struct test_jmp_buf {
+	jmp_buf env;
+	/*
+	 * Auto-variables changed between setjmp() and longjmp() must be
+	 * static or volatile. Otherwise the result is undefined.
+	 */
+	volatile int val;
+};
+
+/**
+ * test_longjmp() - test longjmp function
+ *
+ * @i is passed to longjmp.
+ * @i << 8 is set in the environment structure.
+ *
+ * @env:	environment
+ * @i:		value passed to longjmp()
+ */
+static void noinline test_longjmp(struct test_jmp_buf *env, int i)
+{
+	env->val = i << 8;
+	longjmp(env->env, i);
+}
+
+/**
+ * test_setjmp() - test setjmp function
+ *
+ * setjmp() will return the value @i passed to longjmp() if @i is non-zero.
+ * For @i == 0 we expect return value 1.
+ *
+ * @i << 8 will be set by test_longjmp in the environment structure.
+ * This value can be used to check that the stack frame is restored.
+ *
+ * We return the XORed values to allow simply check both@once.
+ *
+ * @i:		value passed to longjmp()
+ * Return:	values return by longjmp()
+ */
+static int test_setjmp(int i)
+{
+	struct test_jmp_buf env;
+	int ret;
+
+	env.val = -1;
+	ret = setjmp(env.env);
+	if (ret)
+		return ret ^ env.val;
+	test_longjmp(&env, i);
+	/* We should not arrive here */
+	return 0x1000;
+}
+
+static int lib_test_longjmp(struct unit_test_state *uts)
+{
+	int i;
+
+	for (i = -3; i < 0; ++i)
+		ut_asserteq(i ^ (i << 8) , test_setjmp(i));
+	ut_asserteq(1, test_setjmp(0));
+	for (i = 1; i < 4; ++i)
+		ut_asserteq(i ^ (i << 8), test_setjmp(i));
+	return 0;
+}
+LIB_TEST(lib_test_longjmp, 0);
--
2.30.2

[PATCH v4 2/2] test: unit test for longjmp

[Leo Liang]

On Thu, Mar 25, 2021 at 03:31:50PM +0800, Heinrich Schuchardt wrote:
> Provide a unit test for the longjmp() library function
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> ----
> v4:
> 	use volatile for variable changed between setjmp and longjmp
> v3:
> 	check variable on stack
> v2:
> 	no change
> ---
>  test/lib/Makefile  |  1 +
>  test/lib/longjmp.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 78 insertions(+)
>  create mode 100644 test/lib/longjmp.c
> 
> diff --git a/test/lib/Makefile b/test/lib/Makefile
> index 97c11e35a8..a30f615aa9 100644
> --- a/test/lib/Makefile
> +++ b/test/lib/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_EFI_LOADER) += efi_device_path.o
>  obj-$(CONFIG_EFI_SECURE_BOOT) += efi_image_region.o
>  obj-y += hexdump.o
>  obj-y += lmb.o
> +obj-y += longjmp.o
>  obj-$(CONFIG_CONSOLE_RECORD) += test_print.o
>  obj-$(CONFIG_SSCANF) += sscanf.o
>  obj-y += string.o
> diff --git a/test/lib/longjmp.c b/test/lib/longjmp.c
> new file mode 100644
> index 0000000000..bd1fe1aff6
> --- /dev/null
> +++ b/test/lib/longjmp.c
> @@ -0,0 +1,77 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Test setjmp(), longjmp()
> + *
> + * Copyright (c) 2021, Heinrich Schuchardt <xypron.glpk@gmx.de>
> + */
> +
> +#include <common.h>
> +#include <test/lib.h>
> +#include <test/test.h>
> +#include <test/ut.h>
> +#include <asm/setjmp.h>
> +
> +struct test_jmp_buf {
> +	jmp_buf env;
> +	/*
> +	 * Auto-variables changed between setjmp() and longjmp() must be
> +	 * static or volatile. Otherwise the result is undefined.
> +	 */
> +	volatile int val;
> +};
> +
> +/**
> + * test_longjmp() - test longjmp function
> + *
> + * @i is passed to longjmp.
> + * @i << 8 is set in the environment structure.
> + *
> + * @env:	environment
> + * @i:		value passed to longjmp()
> + */
> +static void noinline test_longjmp(struct test_jmp_buf *env, int i)
> +{
> +	env->val = i << 8;
> +	longjmp(env->env, i);
> +}
> +
> +/**
> + * test_setjmp() - test setjmp function
> + *
> + * setjmp() will return the value @i passed to longjmp() if @i is non-zero.
> + * For @i == 0 we expect return value 1.
> + *
> + * @i << 8 will be set by test_longjmp in the environment structure.
> + * This value can be used to check that the stack frame is restored.
> + *
> + * We return the XORed values to allow simply check both at once.
> + *
> + * @i:		value passed to longjmp()
> + * Return:	values return by longjmp()
> + */
> +static int test_setjmp(int i)
> +{
> +	struct test_jmp_buf env;
> +	int ret;
> +
> +	env.val = -1;
> +	ret = setjmp(env.env);
> +	if (ret)
> +		return ret ^ env.val;
> +	test_longjmp(&env, i);
> +	/* We should not arrive here */
> +	return 0x1000;
> +}
> +
> +static int lib_test_longjmp(struct unit_test_state *uts)
> +{
> +	int i;
> +
> +	for (i = -3; i < 0; ++i)
> +		ut_asserteq(i ^ (i << 8) , test_setjmp(i));
> +	ut_asserteq(1, test_setjmp(0));
> +	for (i = 1; i < 4; ++i)
> +		ut_asserteq(i ^ (i << 8), test_setjmp(i));
> +	return 0;
> +}
> +LIB_TEST(lib_test_longjmp, 0);
> --
> 2.30.2
> 

Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>