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121d340b |
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02-Feb-2023 |
Benjamin Gray <bgray@linux.ibm.com> |
selftests/powerpc: Add read/write debugfs file, int Debugfs files are not always integers, so make *_file return/write a byte buffer, and *_int deal with int values specifically. This increases consistency with the other file read/write helpers. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230203003947.38033-3-bgray@linux.ibm.com
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3a72c94e |
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23-Feb-2021 |
Russell Currey <ruscur@russell.cc> |
selftests/powerpc: Fix L1D flushing tests for Power10 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
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0d239f3b |
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16-Nov-2020 |
Daniel Axtens <dja@axtens.net> |
selftests/powerpc: refactor entry and rfi_flush tests 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>
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fcb48454 |
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16-Nov-2020 |
Russell Currey <ruscur@russell.cc> |
selftests/powerpc: rfi_flush: disable entry flush if present 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>
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3a31518a |
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18-Aug-2020 |
Michael Ellerman <mpe@ellerman.id.au> |
selftests/powerpc: Skip security tests on older CPUs Both these tests use PMU events that only work on newer CPUs, so skip them on older CPUs. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200819015727.1977134-6-mpe@ellerman.id.au
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d8900239 |
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18-Aug-2020 |
Michael Ellerman <mpe@ellerman.id.au> |
selftests/powerpc: Move set_dscr() into rfi_flush.c This version of set_dscr() was added for the RFI flush test, and is fairly specific to it. It also clashes with the version of set_dscr() in dscr/dscr.h. So move it into the RFI flush test where it's used. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200819015727.1977134-3-mpe@ellerman.id.au
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a95ecac5 |
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23-Oct-2018 |
Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> |
selftests/powerpc: Relax L1d miss targets for rfi_flush test When running the rfi_flush test, if the system is loaded, we see two issues: 1. The L1d misses when rfi_flush is disabled increase significantly due to other workloads interfering with the cache. 2. The L1d misses when rfi_flush is enabled sometimes goes slightly below the expected number of misses. To address these, let's relax the expected number of L1d misses: 1. When rfi_flush is disabled, we allow upto half the expected number of the misses for when rfi_flush is enabled. 2. When rfi_flush is enabled, we allow ~1% lower number of cache misses. Reported-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Tested-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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d2bf7932 |
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21-May-2018 |
Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> |
selftests/powerpc: Add test to verify rfi flush across a system call This adds a test to verify proper functioning of the rfi flush capability implemented to mitigate meltdown. The test works by measuring the number of L1d cache misses encountered while loading data from memory. Across a system call, since the L1d cache is flushed when rfi_flush is enabled, the number of cache misses is expected to be relative to the number of cachelines corresponding to the data being loaded. The current system setting is reflected via powerpc/rfi_flush under debugfs (assumed to be /sys/kernel/debug/). This test verifies the expected result with rfi_flush enabled as well as when it is disabled. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> [mpe: Add SPDX tags, clang format, skip if the debugfs is missing, use __u64 and SANE_USERSPACE_TYPES to avoid printf() build errors.] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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