riscv: Add tests for riscv module loading

Add test cases for the two main groups of relocations added: SUB and
SET, along with uleb128.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20231101-module_relocations-v9-3-8dfa3483c400@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/Kconfig.debug

@@ -0,0 +1 @@
+source "arch/riscv/kernel/tests/Kconfig.debug"

arch/riscv/kernel/Makefile

@@ -57,6 +57,7 @@ obj-y	+= stacktrace.o
 obj-y	+= cacheinfo.o
 obj-y	+= patch.o
 obj-y	+= probes/
+obj-y	+= tests/
 obj-$(CONFIG_MMU) += vdso.o vdso/
 
 obj-$(CONFIG_RISCV_M_MODE)	+= traps_misaligned.o

arch/riscv/kernel/tests/Kconfig.debug

@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "arch/riscv/kernel Testing and Coverage"
+
+config AS_HAS_ULEB128
+	def_bool $(as-instr,.reloc label$(comma) R_RISCV_SET_ULEB128$(comma) 127\n.reloc label$(comma) R_RISCV_SUB_ULEB128$(comma) 127\nlabel:\n.word 0)
+
+menuconfig RUNTIME_KERNEL_TESTING_MENU
+       bool "arch/riscv/kernel runtime Testing"
+       def_bool y
+       help
+         Enable riscv kernel runtime testing.
+
+if RUNTIME_KERNEL_TESTING_MENU
+
+config RISCV_MODULE_LINKING_KUNIT
+       bool "KUnit test riscv module linking at runtime" if !KUNIT_ALL_TESTS
+       depends on KUNIT
+       default KUNIT_ALL_TESTS
+       help
+         Enable this option to test riscv module linking at boot. This will
+	 enable a module called "test_module_linking".
+
+         KUnit tests run during boot and output the results to the debug log
+         in TAP format (http://testanything.org/). Only useful for kernel devs
+         running the KUnit test harness, and not intended for inclusion into a
+         production build.
+
+         For more information on KUnit and unit tests in general please refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+         If unsure, say N.
+
+endif # RUNTIME_TESTING_MENU
+
+endmenu # "arch/riscv/kernel runtime Testing"

arch/riscv/kernel/tests/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_RISCV_MODULE_LINKING_KUNIT)	+= module_test/

arch/riscv/kernel/tests/module_test/Makefile

@@ -0,0 +1,15 @@
+obj-m += test_module_linking.o
+
+test_sub := test_sub6.o test_sub8.o test_sub16.o test_sub32.o test_sub64.o
+
+test_set := test_set6.o test_set8.o test_set16.o test_set32.o
+
+test_module_linking-objs += $(test_sub)
+
+test_module_linking-objs += $(test_set)
+
+ifeq ($(CONFIG_AS_HAS_ULEB128),y)
+test_module_linking-objs += test_uleb128.o
+endif
+
+test_module_linking-objs += test_module_linking_main.o

arch/riscv/kernel/tests/module_test/test_module_linking_main.c

@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <kunit/test.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Test module linking");
+
+extern int test_set32(void);
+extern int test_set16(void);
+extern int test_set8(void);
+extern int test_set6(void);
+extern long test_sub64(void);
+extern int test_sub32(void);
+extern int test_sub16(void);
+extern int test_sub8(void);
+extern int test_sub6(void);
+
+#ifdef CONFIG_AS_HAS_ULEB128
+extern int test_uleb_basic(void);
+extern int test_uleb_large(void);
+#endif
+
+#define CHECK_EQ(lhs, rhs) KUNIT_ASSERT_EQ(test, lhs, rhs)
+
+void run_test_set(struct kunit *test);
+void run_test_sub(struct kunit *test);
+void run_test_uleb(struct kunit *test);
+
+void run_test_set(struct kunit *test)
+{
+	int val32 = test_set32();
+	int val16 = test_set16();
+	int val8 = test_set8();
+	int val6 = test_set6();
+
+	CHECK_EQ(val32, 0);
+	CHECK_EQ(val16, 0);
+	CHECK_EQ(val8, 0);
+	CHECK_EQ(val6, 0);
+}
+
+void run_test_sub(struct kunit *test)
+{
+	int val64 = test_sub64();
+	int val32 = test_sub32();
+	int val16 = test_sub16();
+	int val8 = test_sub8();
+	int val6 = test_sub6();
+
+	CHECK_EQ(val64, 0);
+	CHECK_EQ(val32, 0);
+	CHECK_EQ(val16, 0);
+	CHECK_EQ(val8, 0);
+	CHECK_EQ(val6, 0);
+}
+
+#ifdef CONFIG_AS_HAS_ULEB128
+void run_test_uleb(struct kunit *test)
+{
+	int val_uleb = test_uleb_basic();
+	int val_uleb2 = test_uleb_large();
+
+	CHECK_EQ(val_uleb, 0);
+	CHECK_EQ(val_uleb2, 0);
+}
+#endif
+
+static struct kunit_case __refdata riscv_module_linking_test_cases[] = {
+	KUNIT_CASE(run_test_set),
+	KUNIT_CASE(run_test_sub),
+#ifdef CONFIG_AS_HAS_ULEB128
+	KUNIT_CASE(run_test_uleb),
+#endif
+	{}
+};
+
+static struct kunit_suite riscv_module_linking_test_suite = {
+	.name = "riscv_checksum",
+	.test_cases = riscv_module_linking_test_cases,
+};
+
+kunit_test_suites(&riscv_module_linking_test_suite);

arch/riscv/kernel/tests/module_test/test_set16.S

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set16
+test_set16:
+	lw	a0, set16
+	la	t0, set16
+#ifdef CONFIG_32BIT
+	slli	t0, t0, 16
+	srli	t0, t0, 16
+#else
+	slli	t0, t0, 48
+	srli	t0, t0, 48
+#endif
+	sub	a0, a0, t0
+	ret
+.data
+set16:
+	.reloc set16, R_RISCV_SET16, set16
+	.word 0

arch/riscv/kernel/tests/module_test/test_set32.S

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set32
+test_set32:
+	lw	a0, set32
+	la	t0, set32
+#ifndef CONFIG_32BIT
+	slli	t0, t0, 32
+	srli	t0, t0, 32
+#endif
+	sub	a0, a0, t0
+	ret
+.data
+set32:
+	.reloc set32, R_RISCV_SET32, set32
+	.word 0

arch/riscv/kernel/tests/module_test/test_set6.S

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set6
+test_set6:
+	lw	a0, set6
+	la	t0, set6
+#ifdef CONFIG_32BIT
+	slli	t0, t0, 26
+	srli	t0, t0, 26
+#else
+	slli	t0, t0, 58
+	srli	t0, t0, 58
+#endif
+	sub	a0, a0, t0
+	ret
+.data
+set6:
+	.reloc set6, R_RISCV_SET6, set6
+	.word 0

arch/riscv/kernel/tests/module_test/test_set8.S

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set8
+test_set8:
+	lw	a0, set8
+	la	t0, set8
+#ifdef CONFIG_32BIT
+	slli	t0, t0, 24
+	srli	t0, t0, 24
+#else
+	slli	t0, t0, 56
+	srli	t0, t0, 56
+#endif
+	sub	a0, a0, t0
+	ret
+.data
+set8:
+	.reloc set8, R_RISCV_SET8, set8
+	.word 0

arch/riscv/kernel/tests/module_test/test_sub16.S

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub16
+test_sub16:
+	lh	a0, sub16
+	addi	a0, a0, -32
+	ret
+first:
+	.space 32
+second:
+
+.data
+sub16:
+	.reloc		sub16, R_RISCV_ADD16, second
+	.reloc		sub16, R_RISCV_SUB16, first
+	.half		0

arch/riscv/kernel/tests/module_test/test_sub32.S

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub32
+test_sub32:
+	lw	a0, sub32
+	addi	a0, a0, -32
+	ret
+first:
+	.space 32
+second:
+
+.data
+sub32:
+	.reloc		sub32, R_RISCV_ADD32, second
+	.reloc		sub32, R_RISCV_SUB32, first
+	.word		0

arch/riscv/kernel/tests/module_test/test_sub6.S

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub6
+test_sub6:
+	lb	a0, sub6
+	addi	a0, a0, -32
+	ret
+first:
+	.space 32
+second:
+
+.data
+sub6:
+	.reloc		sub6, R_RISCV_SET6, second
+	.reloc		sub6, R_RISCV_SUB6, first
+	.byte		0

arch/riscv/kernel/tests/module_test/test_sub64.S

@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub64
+test_sub64:
+#ifdef CONFIG_32BIT
+	lw	a0, sub64
+#else
+	ld	a0, sub64
+#endif
+	addi	a0, a0, -32
+	ret
+first:
+	.space 32
+second:
+
+.data
+sub64:
+	.reloc		sub64, R_RISCV_ADD64, second
+	.reloc		sub64, R_RISCV_SUB64, first
+	.word		0
+	.word		0

arch/riscv/kernel/tests/module_test/test_sub8.S

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub8
+test_sub8:
+	lb	a0, sub8
+	addi	a0, a0, -32
+	ret
+first:
+	.space 32
+second:
+
+.data
+sub8:
+	.reloc		sub8, R_RISCV_ADD8, second
+	.reloc		sub8, R_RISCV_SUB8, first
+	.byte		0

arch/riscv/kernel/tests/module_test/test_uleb128.S

@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_uleb_basic
+test_uleb_basic:
+	ld	a0, second
+	addi	a0, a0, -127
+	ret
+
+.global test_uleb_large
+test_uleb_large:
+	ld	a0, fourth
+	addi	a0, a0, -0x07e8
+	ret
+
+.data
+first:
+	.space 127
+second:
+	.reloc second, R_RISCV_SET_ULEB128, second
+	.reloc second, R_RISCV_SUB_ULEB128, first
+	.dword 0
+third:
+	.space 1000
+fourth:
+	.reloc fourth, R_RISCV_SET_ULEB128, fourth
+	.reloc fourth, R_RISCV_SUB_ULEB128, third
+	.dword 0