linux-stable.git/tools/testing/selftests/powerpc/security, branch linux-5.17.y Linux kernel stable tree selftests/powerpc: skip tests for unavailable mitigations. 2021-12-16T10:31:46+00:00 Sachin Sant sachinp@linux.vnet.ibm.com 2021-12-13T16:42:23+00:00 18678591846d668649fbd4f87b4a4c470818d386 Mitigation patching test iterates over a set of mitigations irrespective of whether a certain mitigation is supported/available in the kernel. This causes following messages on a kernel where some mitigations are unavailable: Spawned threads enabling/disabling mitigations ... cat: entry_flush: No such file or directory cat: uaccess_flush: No such file or directory Waiting for timeout ... OK This patch adds a check for available mitigations in the kernel. Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Signed-off-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Reviewed-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/163941374362.36967.18016981579099073379.sendpatchset@1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa 
Mitigation patching test iterates over a set of mitigations irrespective
of whether a certain mitigation is supported/available in the kernel.
This causes following messages on a kernel where some mitigations
are unavailable:

  Spawned threads enabling/disabling mitigations ...
  cat: entry_flush: No such file or directory
  cat: uaccess_flush: No such file or directory
  Waiting for timeout ...
  OK

This patch adds a check for available mitigations in the kernel.

Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Reviewed-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/163941374362.36967.18016981579099073379.sendpatchset@1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa
selftests/powerpc/spectre_v2: Return skip code when miss_percent is high 2021-12-09T11:41:21+00:00 Thadeu Lima de Souza Cascardo cascardo@canonical.com 2021-12-07T13:05:57+00:00 3c42e9542050d49610077e083c7c3f5fd5e26820 A mis-match between reported and actual mitigation is not restricted to the Vulnerable case. The guest might also report the mitigation as "Software count cache flush" and the host will still mitigate with branch cache disabled. So, instead of skipping depending on the detected mitigation, simply skip whenever the detected miss_percent is the expected one for a fully mitigated system, that is, above 95%. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211207130557.40566-1-cascardo@canonical.com 
A mis-match between reported and actual mitigation is not restricted to the
Vulnerable case. The guest might also report the mitigation as "Software
count cache flush" and the host will still mitigate with branch cache
disabled.

So, instead of skipping depending on the detected mitigation, simply skip
whenever the detected miss_percent is the expected one for a fully
mitigated system, that is, above 95%.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211207130557.40566-1-cascardo@canonical.com
selftests/powerpc: Use date instead of EPOCHSECONDS in mitigation-patching.sh 2021-10-27T11:34:02+00:00 Russell Currey ruscur@russell.cc 2021-10-25T10:24:36+00:00 cb662608e546d755e3e1b51b30a269459323bf24 The EPOCHSECONDS environment variable was added in bash 5.0 (released 2019). Some distributions of the "stable" and "long-term" variety ship older versions of bash than this, so swap to using the date command instead. "%s" was added to coreutils `date` in 1993 so we should be good, but who knows, it is a GNU extension and not part of the POSIX spec for `date`. Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211025102436.19177-1-ruscur@russell.cc 
The EPOCHSECONDS environment variable was added in bash 5.0 (released
2019).  Some distributions of the "stable" and "long-term" variety ship
older versions of bash than this, so swap to using the date command
instead.

"%s" was added to coreutils `date` in 1993 so we should be good, but who
knows, it is a GNU extension and not part of the POSIX spec for `date`.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211025102436.19177-1-ruscur@russell.cc
selftests/powerpc: Add test of mitigation patching 2021-05-17T05:27:47+00:00 Michael Ellerman mpe@ellerman.id.au 2021-05-07T06:42:25+00:00 34f7f79827ec4db30cff9001dfba19f496473e8d We recently discovered some of our mitigation patching was not safe against other CPUs running concurrently. Add a test which enable/disables all mitigations in a tight loop while also running some stress load. On an unpatched system this almost always leads to an oops and panic/reboot, but we also check if the kernel becomes tainted in case we have a non-fatal oops. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210507064225.1556312-1-mpe@ellerman.id.au 
We recently discovered some of our mitigation patching was not safe
against other CPUs running concurrently.

Add a test which enable/disables all mitigations in a tight loop while
also running some stress load. On an unpatched system this almost always
leads to an oops and panic/reboot, but we also check if the kernel
becomes tainted in case we have a non-fatal oops.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210507064225.1556312-1-mpe@ellerman.id.au
selftests/powerpc: Add uaccess flush test 2021-04-22T15:38:03+00:00 Thadeu Lima de Souza Cascardo cascardo@canonical.com 2021-02-25T06:19:49+00:00 da650ada100956b0f00aa4fe9ce33103378ce9ca Also based on the RFI and entry flush tests, it counts the L1D misses by doing a syscall that does user access: uname, in this case. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> [dja: forward port, rename function] Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210225061949.1213404-1-dja@axtens.net 
Also based on the RFI and entry flush tests, it counts the L1D misses
by doing a syscall that does user access: uname, in this case.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[dja: forward port, rename function]
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210225061949.1213404-1-dja@axtens.net
selftests/powerpc: Fix L1D flushing tests for Power10 2021-03-24T03:09:29+00:00 Russell Currey ruscur@russell.cc 2021-02-23T07:02:27+00:00 3a72c94ebfb1f171eba0715998010678a09ec796 The rfi_flush and entry_flush selftests work by using the PM_LD_MISS_L1 perf event to count L1D misses. The value of this event has changed over time: - Power7 uses 0x400f0 - Power8 and Power9 use both 0x400f0 and 0x3e054 - Power10 uses only 0x3e054 Rather than relying on raw values, configure perf to count L1D read misses in the most explicit way available. This fixes the selftests to work on systems without 0x400f0 as PM_LD_MISS_L1, and should change no behaviour for systems that the tests already worked on. The only potential downside is that referring to a specific perf event requires PMU support implemented in the kernel for that platform. Signed-off-by: Russell Currey <ruscur@russell.cc> Acked-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210223070227.2916871-1-ruscur@russell.cc 
The rfi_flush and entry_flush selftests work by using the PM_LD_MISS_L1
perf event to count L1D misses.  The value of this event has changed
over time:

- Power7 uses 0x400f0
- Power8 and Power9 use both 0x400f0 and 0x3e054
- Power10 uses only 0x3e054

Rather than relying on raw values, configure perf to count L1D read
misses in the most explicit way available.

This fixes the selftests to work on systems without 0x400f0 as
PM_LD_MISS_L1, and should change no behaviour for systems that the tests
already worked on.

The only potential downside is that referring to a specific perf event
requires PMU support implemented in the kernel for that platform.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Acked-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210223070227.2916871-1-ruscur@russell.cc
selftests/powerpc: update .gitignore 2020-12-03T14:01:21+00:00 Daniel Axtens dja@axtens.net 2020-12-01T14:44:27+00:00 f0812f6ca8299e864fe0f41bd7ffdaae3ce7630e I did an in-place build of the self-tests and found that it left the tree dirty. Add missed test binaries to .gitignore Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201201144427.1228745-1-dja@axtens.net 
I did an in-place build of the self-tests and found that it left
the tree dirty.

Add missed test binaries to .gitignore

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201201144427.1228745-1-dja@axtens.net
selftests/powerpc: refactor entry and rfi_flush tests 2020-11-19T12:47:23+00:00 Daniel Axtens dja@axtens.net 2020-11-17T05:59:15+00:00 0d239f3b03efc78fb5b290aff6c747fecd3b98cb For simplicity in backporting, the original entry_flush test contained a lot of duplicated code from the rfi_flush test. De-duplicate that code. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
For simplicity in backporting, the original entry_flush test contained
a lot of duplicated code from the rfi_flush test. De-duplicate that code.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
selftests/powerpc: entry flush test 2020-11-19T12:47:20+00:00 Daniel Axtens dja@axtens.net 2020-11-17T05:59:14+00:00 89a83a0c69c81a25ce91002b90ca27ed86132a0a Add a test modelled on the RFI flush test which counts the number of L1D misses doing a simple syscall with the entry flush on and off. For simplicity of backporting, this test duplicates a lot of code from rfi_flush. We clean that up in the next patch. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
Add a test modelled on the RFI flush test which counts the number
of L1D misses doing a simple syscall with the entry flush on and off.

For simplicity of backporting, this test duplicates a lot of code from
rfi_flush. We clean that up in the next patch.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
selftests/powerpc: rfi_flush: disable entry flush if present 2020-11-19T12:47:12+00:00 Russell Currey ruscur@russell.cc 2020-11-17T05:59:11+00:00 fcb48454c23c5679d1a2e252f127642e91b05cbe We are about to add an entry flush. The rfi (exit) flush test measures the number of L1D flushes over a syscall with the RFI flush enabled and disabled. But if the entry flush is also enabled, the effect of enabling and disabling the RFI flush is masked. If there is a debugfs entry for the entry flush, disable it during the RFI flush and restore it later. Reported-by: Spoorthy S <spoorts2@in.ibm.com> Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> 
We are about to add an entry flush. The rfi (exit) flush test measures
the number of L1D flushes over a syscall with the RFI flush enabled and
disabled. But if the entry flush is also enabled, the effect of enabling
and disabling the RFI flush is masked.

If there is a debugfs entry for the entry flush, disable it during the RFI
flush and restore it later.

Reported-by: Spoorthy S <spoorts2@in.ibm.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>