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Subject[PATCH bpf-next 2/2] bpf: selftests: Add bpf_task_pt_regs() selftest
Date
This test retrieves the uprobe's pt_regs in two different ways and
compares the contents in an arch-agnostic way.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
---
.../selftests/bpf/prog_tests/task_pt_regs.c | 50 +++++++++++++++++++
.../selftests/bpf/progs/test_task_pt_regs.c | 29 +++++++++++
2 files changed, 79 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/task_pt_regs.c
create mode 100644 tools/testing/selftests/bpf/progs/test_task_pt_regs.c

diff --git a/tools/testing/selftests/bpf/prog_tests/task_pt_regs.c b/tools/testing/selftests/bpf/prog_tests/task_pt_regs.c
new file mode 100644
index 000000000000..3f0fc2267c1c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/task_pt_regs.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <test_progs.h>
+#include <linux/ptrace.h>
+#include "test_task_pt_regs.skel.h"
+
+void test_task_pt_regs(void)
+{
+ int duration = 0;
+ struct test_task_pt_regs *skel;
+ struct bpf_link *uprobe_link;
+ size_t uprobe_offset;
+ ssize_t base_addr;
+ bool match;
+
+ base_addr = get_base_addr();
+ if (CHECK(base_addr < 0, "get_base_addr",
+ "failed to find base addr: %zd", base_addr))
+ return;
+ uprobe_offset = get_uprobe_offset(&get_base_addr, base_addr);
+
+ skel = test_task_pt_regs__open_and_load();
+ if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+ return;
+ if (CHECK(!skel->bss, "check_bss", ".bss wasn't mmap()-ed\n"))
+ goto cleanup;
+
+ uprobe_link = bpf_program__attach_uprobe(skel->progs.handle_uprobe,
+ false /* retprobe */,
+ 0 /* self pid */,
+ "/proc/self/exe",
+ uprobe_offset);
+ if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe"))
+ goto cleanup;
+ skel->links.handle_uprobe = uprobe_link;
+
+ /* trigger & validate uprobe */
+ get_base_addr();
+
+ if (CHECK(skel->bss->uprobe_res != 1, "check_uprobe_res",
+ "wrong uprobe res: %d\n", skel->bss->uprobe_res))
+ goto cleanup;
+
+ match = !memcmp(&skel->bss->current_regs, &skel->bss->ctx_regs,
+ sizeof(skel->bss->current_regs));
+ CHECK(!match, "check_regs_match", "registers did not match");
+
+cleanup:
+ test_task_pt_regs__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_task_pt_regs.c b/tools/testing/selftests/bpf/progs/test_task_pt_regs.c
new file mode 100644
index 000000000000..6c059f1cfa1b
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_task_pt_regs.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ptrace.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+struct pt_regs current_regs = {};
+struct pt_regs ctx_regs = {};
+int uprobe_res = 0;
+
+SEC("uprobe/trigger_func")
+int handle_uprobe(struct pt_regs *ctx)
+{
+ struct task_struct *current;
+ struct pt_regs *regs;
+
+ current = bpf_get_current_task_btf();
+ regs = (struct pt_regs *) bpf_task_pt_regs(current);
+ __builtin_memcpy(&current_regs, regs, sizeof(*regs));
+ __builtin_memcpy(&ctx_regs, ctx, sizeof(*ctx));
+
+ /* Prove that uprobe was run */
+ uprobe_res = 1;
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.32.0
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