linux/tools/testing/selftests/powerpc/include/utils.h

211 lines
5.5 KiB

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
2019-05-20 20:55:20 +10:00
selftests/powerpc: Add support to fetch "platform" and "base platform" from auxv to detect platform. The /proc/self/auxv contains information about "platform" on any system. Also "base platform" which is an indication about platform string corresponding to the real PVR. When systems are booted in compat mode, say, power10 booted in power9 mode, "platform" will point to power9 whereas base platform will point to power10. Incase, if the distro doesn't support platform indicated by real PVR, base platform will have a default value. The mismatch of platform/base platform is an indication of system booted in compat mode. In such cases, distro will have a Generic Compat registered which supports basic features for performance monitoring. Some of the selftest needs to be handled differently ( ex: generic events, alternative events, bhrb filter map) in Generic Compat PMU. Hence selftest framework needs utility functions to identify such cases. One way is make sure of auxv information. Below condition can be used to detect if Generic Compat PMU is registered. ie: if ((AT_PLATFORM != AT_BASE_PLATFORM) && (AT_BASE_PLATFORM != PVR)) this indicates Generic Compat PMU. Add utility function in "include/utils.h" to return: AT_PLATFORM and AT_BASE_PLATFORM from auxv. Also update misc.c in "sampling_tests" folder to add function to use above check to determine presence of generic compat pmu. In other architecture ( like x86 ), pmu_name is exposed via "/sys/bus/event_source/devices/cpu/caps". The same could be used in powerpc in future. Since currently we don't have the "caps" support in powerpc, patch uses auxv information to detect platform type and compat mode. But as placeholder utility function is added considering possiblity of getting "caps" information via sysfs. If that doesn't exist, fallback to using auxv information. Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220610134113.62991-3-atrajeev@linux.vnet.ibm.com
2022-06-10 19:10:40 +05:30