kcsan: Remove debugfs test command

Remove the debugfs test command, as it is no longer needed now that we
have the KUnit+Torture based kcsan-test module. This is to avoid
confusion around how KCSAN should be tested, as only the kcsan-test
module is maintained.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c
index 116bdd8..de1da1b 100644 (file)
--- a/kernel/kcsan/debugfs.c
+++ b/kernel/kcsan/debugfs.c
@@ -98,66 +98,6 @@ static noinline void microbenchmark(unsigned long iters)
        current->kcsan_ctx = ctx_save;
 }
 
-/*
- * Simple test to create conflicting accesses. Write 'test=<iters>' to KCSAN's
- * debugfs file from multiple tasks to generate real conflicts and show reports.
- */
-static long test_dummy;
-static long test_flags;
-static long test_scoped;
-static noinline void test_thread(unsigned long iters)
-{
-       const long CHANGE_BITS = 0xff00ff00ff00ff00L;
-       const struct kcsan_ctx ctx_save = current->kcsan_ctx;
-       cycles_t cycles;
-
-       /* We may have been called from an atomic region; reset context. */
-       memset(&current->kcsan_ctx, 0, sizeof(current->kcsan_ctx));
-
-       pr_info("KCSAN: %s begin | iters: %lu\n", __func__, iters);
-       pr_info("test_dummy@%px, test_flags@%px, test_scoped@%px,\n",
-               &test_dummy, &test_flags, &test_scoped);
-
-       cycles = get_cycles();
-       while (iters--) {
-               /* These all should generate reports. */
-               __kcsan_check_read(&test_dummy, sizeof(test_dummy));
-               ASSERT_EXCLUSIVE_WRITER(test_dummy);
-               ASSERT_EXCLUSIVE_ACCESS(test_dummy);
-
-               ASSERT_EXCLUSIVE_BITS(test_flags, ~CHANGE_BITS); /* no report */
-               __kcsan_check_read(&test_flags, sizeof(test_flags)); /* no report */
-
-               ASSERT_EXCLUSIVE_BITS(test_flags, CHANGE_BITS); /* report */
-               __kcsan_check_read(&test_flags, sizeof(test_flags)); /* no report */
-
-               /* not actually instrumented */
-               WRITE_ONCE(test_dummy, iters);  /* to observe value-change */
-               __kcsan_check_write(&test_dummy, sizeof(test_dummy));
-
-               test_flags ^= CHANGE_BITS; /* generate value-change */
-               __kcsan_check_write(&test_flags, sizeof(test_flags));
-
-               BUG_ON(current->kcsan_ctx.scoped_accesses.prev);
-               {
-                       /* Should generate reports anywhere in this block. */
-                       ASSERT_EXCLUSIVE_WRITER_SCOPED(test_scoped);
-                       ASSERT_EXCLUSIVE_ACCESS_SCOPED(test_scoped);
-                       BUG_ON(!current->kcsan_ctx.scoped_accesses.prev);
-                       /* Unrelated accesses. */
-                       __kcsan_check_access(&cycles, sizeof(cycles), 0);
-                       __kcsan_check_access(&cycles, sizeof(cycles), KCSAN_ACCESS_ATOMIC);
-               }
-               BUG_ON(current->kcsan_ctx.scoped_accesses.prev);
-       }
-       cycles = get_cycles() - cycles;
-
-       pr_info("KCSAN: %s end   | cycles: %llu\n", __func__, cycles);
-
-       /* restore context */
-       current->kcsan_ctx = ctx_save;
-}
-
 static int cmp_filterlist_addrs(const void *rhs, const void *lhs)
 {
        const unsigned long a = *(const unsigned long *)rhs;
@@ -306,12 +246,6 @@ debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *o
                if (kstrtoul(&arg[strlen("microbench=")], 0, &iters))
                        return -EINVAL;
                microbenchmark(iters);
-       } else if (str_has_prefix(arg, "test=")) {
-               unsigned long iters;
-
-               if (kstrtoul(&arg[strlen("test=")], 0, &iters))
-                       return -EINVAL;
-               test_thread(iters);
        } else if (!strcmp(arg, "whitelist")) {
                set_report_filterlist_whitelist(true);
        } else if (!strcmp(arg, "blacklist")) {