| // 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"); |
| } |
