diff --git a/tools/testing/selftests/powerpc/math/.gitignore b/tools/testing/selftests/powerpc/math/.gitignore index e31ca6f453ed..d0c23b2e4b60 100644 --- a/tools/testing/selftests/powerpc/math/.gitignore +++ b/tools/testing/selftests/powerpc/math/.gitignore @@ -6,3 +6,4 @@ vmx_preempt fpu_signal vmx_signal vsx_preempt +fpu_denormal diff --git a/tools/testing/selftests/powerpc/math/Makefile b/tools/testing/selftests/powerpc/math/Makefile index 11a10d7a2bbd..4e2049d2fd8d 100644 --- a/tools/testing/selftests/powerpc/math/Makefile +++ b/tools/testing/selftests/powerpc/math/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 -TEST_GEN_PROGS := fpu_syscall fpu_preempt fpu_signal vmx_syscall vmx_preempt vmx_signal vsx_preempt +TEST_GEN_PROGS := fpu_syscall fpu_preempt fpu_signal fpu_denormal vmx_syscall vmx_preempt vmx_signal vsx_preempt top_srcdir = ../../../../.. include ../../lib.mk diff --git a/tools/testing/selftests/powerpc/math/fpu_denormal.c b/tools/testing/selftests/powerpc/math/fpu_denormal.c new file mode 100644 index 000000000000..5f96682abaa8 --- /dev/null +++ b/tools/testing/selftests/powerpc/math/fpu_denormal.c @@ -0,0 +1,38 @@ +// 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 +#include + +#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 ; 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"); +}