// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright IBM Corp. 2020 * * This test attempts to cause a FP denormal exception on POWER8 CPUs. Unfortunately * if the denormal handler is not configured or working properly, this can cause a bad * crash in kernel mode when the kernel tries to save FP registers when the process * exits. */ #include <stdio.h> #include <string.h> #include "utils.h" static int test_denormal_fpu(void) { unsigned int m32; unsigned long m64; volatile float f; volatile double d; /* try to induce lfs <denormal> ; stfd */ m32 = 0x00715fcf; /* random denormal */ memcpy((float *)&f, &m32, sizeof(f)); d = f; memcpy(&m64, (double *)&d, sizeof(d)); FAIL_IF((long)(m64 != 0x380c57f3c0000000)); /* renormalised value */ return 0; } int main(int argc, char *argv[]) { return test_harness(test_denormal_fpu, "fpu_denormal"); }