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authorMichael Ellerman <mpe@ellerman.id.au>2019-05-20 20:55:20 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2019-10-30 15:43:57 +1100
commitc790c3d2b0ec5979d83451d0688d1cd07e23d8ba (patch)
tree7477bac3de08b16bff9472adc4d29bac822c5818 /tools/testing/selftests/powerpc/utils.c
parentselftests/powerpc: Fixup clobbers for TM tests (diff)
downloadlinux-dev-c790c3d2b0ec5979d83451d0688d1cd07e23d8ba.tar.xz
linux-dev-c790c3d2b0ec5979d83451d0688d1cd07e23d8ba.zip
selftests/powerpc: Add a test of spectre_v2 mitigations
This test uses the PMU to count branch prediction hits/misses for a known loop, and compare the result to the reported spectre v2 mitigation. This gives us a way of sanity checking that the reported mitigation is actually in effect. Sample output for some cases, eg: Power9: sysfs reports: 'Vulnerable' PM_BR_PRED_CCACHE: result 368 running/enabled 5792777124 PM_BR_MPRED_CCACHE: result 319 running/enabled 5792775546 PM_BR_PRED_PCACHE: result 2147483281 running/enabled 5792773128 PM_BR_MPRED_PCACHE: result 213604201 running/enabled 5792771640 Miss percent 9 % OK - Measured branch prediction rates match reported spectre v2 mitigation. sysfs reports: 'Mitigation: Indirect branch serialisation (kernel only)' PM_BR_PRED_CCACHE: result 895 running/enabled 5780320920 PM_BR_MPRED_CCACHE: result 822 running/enabled 5780312414 PM_BR_PRED_PCACHE: result 2147482754 running/enabled 5780308836 PM_BR_MPRED_PCACHE: result 213639731 running/enabled 5780307912 Miss percent 9 % OK - Measured branch prediction rates match reported spectre v2 mitigation. sysfs reports: 'Mitigation: Indirect branch cache disabled' PM_BR_PRED_CCACHE: result 2147483649 running/enabled 20540186160 PM_BR_MPRED_CCACHE: result 2147483649 running/enabled 20540180056 PM_BR_PRED_PCACHE: result 0 running/enabled 20540176090 PM_BR_MPRED_PCACHE: result 0 running/enabled 20540174182 Miss percent 100 % OK - Measured branch prediction rates match reported spectre v2 mitigation. Power8: sysfs reports: 'Vulnerable' PM_BR_PRED_CCACHE: result 2147483649 running/enabled 3505888142 PM_BR_MPRED_CCACHE: result 9 running/enabled 3505882788 Miss percent 0 % OK - Measured branch prediction rates match reported spectre v2 mitigation. sysfs reports: 'Mitigation: Indirect branch cache disabled' PM_BR_PRED_CCACHE: result 2147483649 running/enabled 16931421988 PM_BR_MPRED_CCACHE: result 2147483649 running/enabled 16931416478 Miss percent 100 % OK - Measured branch prediction rates match reported spectre v2 mitigation. success: spectre_v2 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190520105520.22274-1-mpe@ellerman.id.au
Diffstat (limited to 'tools/testing/selftests/powerpc/utils.c')
-rw-r--r--tools/testing/selftests/powerpc/utils.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/utils.c b/tools/testing/selftests/powerpc/utils.c
index c02d24835db4..5ee0e98c4896 100644
--- a/tools/testing/selftests/powerpc/utils.c
+++ b/tools/testing/selftests/powerpc/utils.c
@@ -127,6 +127,26 @@ bool is_ppc64le(void)
return strcmp(uts.machine, "ppc64le") == 0;
}
+int read_sysfs_file(char *fpath, char *result, size_t result_size)
+{
+ char path[PATH_MAX] = "/sys/";
+ int rc = -1, fd;
+
+ strncat(path, fpath, PATH_MAX - strlen(path) - 1);
+
+ if ((fd = open(path, O_RDONLY)) < 0)
+ return rc;
+
+ rc = read(fd, result, result_size);
+
+ close(fd);
+
+ if (rc < 0)
+ return rc;
+
+ return 0;
+}
+
int read_debugfs_file(char *debugfs_file, int *result)
{
int rc = -1, fd;