diff options
author | Nicholas Piggin <npiggin@gmail.com> | 2020-07-08 17:49:42 +1000 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-07-15 12:02:20 +1000 |
commit | 1f9bb31e58118e14ab66239796f2fbe633e1ad32 (patch) | |
tree | 32ef96d7c2fd02413503e27e2e9edcefa0412c08 /tools | |
parent | 0138ba5783ae0dcc799ad401a1e8ac8333790df9 (diff) | |
download | linux-1f9bb31e58118e14ab66239796f2fbe633e1ad32.tar.bz2 |
selftests/powerpc: Add FPU denormal test
Add a testcase that tries to trigger the FPU denormal exception on
Power8 or earlier CPUs.
Prior to commit 4557ac6b344b ("powerpc/64s/exception: Fix 0x1500
interrupt handler crash") this would trigger a crash such as:
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in: iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4 xt_tcpudp tun bridge stp llc ip6table_filter ip6_tables iptable_filter fuse kvm_hv binfmt_misc squashfs mlx4_ib ib_uverbs dm_multipath scsi_dh_rdac scsi_dh_alua ib_core mlx4_en sr_mod cdrom bnx2x lpfc mlx4_core crc_t10dif scsi_transport_fc sg mdio vmx_crypto crct10dif_vpmsum leds_powernv powernv_rng rng_core led_class powernv_op_panel sunrpc ip_tables x_tables autofs4
CPU: 159 PID: 6854 Comm: fpu_denormal Not tainted 5.8.0-rc2-gcc-8.2.0-00092-g4ec7aaab0828 #192
NIP: c0000000000100ec LR: c00000000001b85c CTR: 0000000000000000
REGS: c000001dd818f770 TRAP: 1500 Not tainted (5.8.0-rc2-gcc-8.2.0-00092-g4ec7aaab0828)
MSR: 900000000290b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 24002884 XER: 20000000
CFAR: c00000000001005c IRQMASK: 1
GPR00: c00000000001c4c8 c000001dd818fa00 c00000000171c200 c000001dd8101570
GPR04: 0000000000000000 c000001dd818fe90 c000001dd8101590 000000000000001d
GPR08: 0000000000000010 0000000000002000 c000001dd818fe90 fffffffffc48ac60
GPR12: 0000000000002200 c000001ffff4f480 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 00007fffab225b40 0000000000000001 c000000001757168
GPR24: c000001dd8101570 c0000018027b00f0 c000001dd8101570 c000000001496098
GPR28: c00000000174ad05 c000001dd8100000 c000001dd8100000 c000001dd8100000
NIP save_fpu+0xa8/0x2ac
LR __giveup_fpu+0x2c/0xd0
Call Trace:
0xc000001dd818fa80 (unreliable)
giveup_all+0x118/0x120
__switch_to+0x124/0x6c0
__schedule+0x390/0xaf0
do_task_dead+0x70/0x80
do_exit+0x8fc/0xe10
do_group_exit+0x64/0xd0
sys_exit_group+0x24/0x30
system_call_exception+0x164/0x270
system_call_common+0xf0/0x278
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of fix patch, add oops log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200708074942.1713396-1-npiggin@gmail.com
Diffstat (limited to 'tools')
-rw-r--r-- | tools/testing/selftests/powerpc/math/.gitignore | 1 | ||||
-rw-r--r-- | tools/testing/selftests/powerpc/math/Makefile | 2 | ||||
-rw-r--r-- | tools/testing/selftests/powerpc/math/fpu_denormal.c | 38 |
3 files changed, 40 insertions, 1 deletions
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 <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"); +} |