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-rw-r--r--tools/testing/selftests/bpf/progs/test_rdonly_maps.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_rdonly_maps.c b/tools/testing/selftests/bpf/progs/test_rdonly_maps.c
new file mode 100644
index 000000000..ecbeea2df
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_rdonly_maps.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+
+#include <linux/ptrace.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+static volatile const struct {
+ unsigned a[4];
+ /*
+ * if the struct's size is multiple of 16, compiler will put it into
+ * .rodata.cst16 section, which is not recognized by libbpf; work
+ * around this by ensuring we don't have 16-aligned struct
+ */
+ char _y;
+} rdonly_values = { .a = {2, 3, 4, 5} };
+
+static volatile struct {
+ unsigned did_run;
+ unsigned iters;
+ unsigned sum;
+} res;
+
+SEC("raw_tracepoint/sys_enter:skip_loop")
+int skip_loop(struct pt_regs *ctx)
+{
+ /* prevent compiler to optimize everything out */
+ unsigned * volatile p = (void *)&rdonly_values.a;
+ unsigned iters = 0, sum = 0;
+
+ /* we should never enter this loop */
+ while (*p & 1) {
+ iters++;
+ sum += *p;
+ p++;
+ }
+ res.did_run = 1;
+ res.iters = iters;
+ res.sum = sum;
+ return 0;
+}
+
+SEC("raw_tracepoint/sys_enter:part_loop")
+int part_loop(struct pt_regs *ctx)
+{
+ /* prevent compiler to optimize everything out */
+ unsigned * volatile p = (void *)&rdonly_values.a;
+ unsigned iters = 0, sum = 0;
+
+ /* validate verifier can derive loop termination */
+ while (*p < 5) {
+ iters++;
+ sum += *p;
+ p++;
+ }
+ res.did_run = 1;
+ res.iters = iters;
+ res.sum = sum;
+ return 0;
+}
+
+SEC("raw_tracepoint/sys_enter:full_loop")
+int full_loop(struct pt_regs *ctx)
+{
+ /* prevent compiler to optimize everything out */
+ unsigned * volatile p = (void *)&rdonly_values.a;
+ int i = sizeof(rdonly_values.a) / sizeof(rdonly_values.a[0]);
+ unsigned iters = 0, sum = 0;
+
+ /* validate verifier can allow full loop as well */
+ while (i > 0 ) {
+ iters++;
+ sum += *p;
+ p++;
+ i--;
+ }
+ res.did_run = 1;
+ res.iters = iters;
+ res.sum = sum;
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";