Extend the kprobes KUnit test with a function containing an LR/SC
sequence and assert that register_kprobe() accepts a probe placed right
before or right after the sequence, and rejects a probe placed on the
LR, on an instruction inside the sequence, or on the SC.

Signed-off-by: Xiaofeng Yuan <[email protected]>
---
 .../kernel/tests/kprobes/test-kprobes-asm.S   | 24 +++++++++++++++++
 .../riscv/kernel/tests/kprobes/test-kprobes.c | 26 +++++++++++++++++++
 .../riscv/kernel/tests/kprobes/test-kprobes.h |  3 +++
 3 files changed, 53 insertions(+)

diff --git a/arch/riscv/kernel/tests/kprobes/test-kprobes-asm.S 
b/arch/riscv/kernel/tests/kprobes/test-kprobes-asm.S
index 15e50934b..6625a960c 100644
--- a/arch/riscv/kernel/tests/kprobes/test-kprobes-asm.S
+++ b/arch/riscv/kernel/tests/kprobes/test-kprobes-asm.S
@@ -100,6 +100,21 @@ test_kprobes_branch_addr8:
        .option pop
 SYM_FUNC_END(test_kprobes_branch)
 
+SYM_FUNC_START(test_kprobes_lrsc)
+.Llrsc_before:
+       nop
+1:
+.Llrsc_lr:
+       lr.w t0, 0(x0)
+.Llrsc_inside:
+       addi t0, t0, 1
+.Llrsc_sc:
+       sc.w t0, t0, 0(x0)
+       bnez t0, 1b
+.Llrsc_after:
+       ret
+SYM_FUNC_END(test_kprobes_lrsc)
+
 #ifdef CONFIG_RISCV_ISA_C
 
 SYM_FUNC_START(test_kprobes_c_j)
@@ -253,3 +268,12 @@ SYM_DATA_START(test_kprobes_functions)
 #endif /* CONFIG_RISCV_ISA_C */
        RISCV_PTR 0
 SYM_DATA_END(test_kprobes_functions)
+
+.section .rodata
+SYM_DATA_START(test_kprobes_lrsc_offsets)
+       RISCV_PTR .Llrsc_before
+       RISCV_PTR .Llrsc_lr
+       RISCV_PTR .Llrsc_inside
+       RISCV_PTR .Llrsc_sc
+       RISCV_PTR .Llrsc_after
+SYM_DATA_END(test_kprobes_lrsc_offsets)
diff --git a/arch/riscv/kernel/tests/kprobes/test-kprobes.c 
b/arch/riscv/kernel/tests/kprobes/test-kprobes.c
index 027424a3f..272753756 100644
--- a/arch/riscv/kernel/tests/kprobes/test-kprobes.c
+++ b/arch/riscv/kernel/tests/kprobes/test-kprobes.c
@@ -43,8 +43,34 @@ static void test_kprobe_riscv(struct kunit *test)
        kfree(kp);
 }
 
+static void test_kprobe_lrsc(struct kunit *test)
+{
+       /*
+        * test_kprobes_lrsc_offsets[] points, in order, at an instruction
+        * right before an LR/SC sequence, the LR itself, an instruction
+        * inside the sequence, the SC, and an instruction right after it.
+        */
+       bool reject[] = { false, true, true, true, false };
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(reject); i++) {
+               struct kprobe kp = {};
+
+               kp.pre_handler = kprobe_dummy_handler;
+               kp.addr = (kprobe_opcode_t *)test_kprobes_lrsc_offsets[i];
+
+               if (reject[i]) {
+                       KUNIT_EXPECT_LT(test, register_kprobe(&kp), 0);
+               } else {
+                       KUNIT_EXPECT_EQ(test, register_kprobe(&kp), 0);
+                       unregister_kprobe(&kp);
+               }
+       }
+}
+
 static struct kunit_case kprobes_testcases[] = {
        KUNIT_CASE(test_kprobe_riscv),
+       KUNIT_CASE(test_kprobe_lrsc),
        {}
 };
 
diff --git a/arch/riscv/kernel/tests/kprobes/test-kprobes.h 
b/arch/riscv/kernel/tests/kprobes/test-kprobes.h
index 537f44aa9..65a8e7217 100644
--- a/arch/riscv/kernel/tests/kprobes/test-kprobes.h
+++ b/arch/riscv/kernel/tests/kprobes/test-kprobes.h
@@ -19,6 +19,9 @@ extern void *test_kprobes_addresses[];
 /* array of functions that return KPROBE_TEST_MAGIC */
 extern long (*test_kprobes_functions[])(void);
 
+/* offsets of the probe points inside test_kprobes_lrsc() */
+extern void *test_kprobes_lrsc_offsets[];
+
 #endif /* __ASSEMBLER__ */
 
 #endif /* TEST_KPROBES_H */
-- 
2.34.1


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