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-rw-r--r--tools/testing/selftests/kvm/lib/string_override.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/string_override.c b/tools/testing/selftests/kvm/lib/string_override.c
new file mode 100644
index 000000000..632398adc
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/string_override.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <stddef.h>
+
+/*
+ * Override the "basic" built-in string helpers so that they can be used in
+ * guest code. KVM selftests don't support dynamic loading in guest code and
+ * will jump into the weeds if the compiler decides to insert an out-of-line
+ * call via the PLT.
+ */
+int memcmp(const void *cs, const void *ct, size_t count)
+{
+ const unsigned char *su1, *su2;
+ int res = 0;
+
+ for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) {
+ if ((res = *su1 - *su2) != 0)
+ break;
+ }
+ return res;
+}
+
+void *memcpy(void *dest, const void *src, size_t count)
+{
+ char *tmp = dest;
+ const char *s = src;
+
+ while (count--)
+ *tmp++ = *s++;
+ return dest;
+}
+
+void *memset(void *s, int c, size_t count)
+{
+ char *xs = s;
+
+ while (count--)
+ *xs++ = c;
+ return s;
+}