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selftests/powerpc: Fix L1D flushing tests for Power10

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[ Upstream commit 3a72c94ebf ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Russell Currey 2021-02-23 17:02:27 +10:00 • committed by Greg Kroah-Hartman
commit b9f9313c75
3 changed files with 6 additions and 2 deletions
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2
tools/testing/selftests/powerpc/security/entry_flush.c
View file

@ -53,7 +53,7 @@ int entry_flush_test(void)
entry_flush = entry_flush_orig;
fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1);
fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
FAIL_IF(fd < 0);
p = (char *)memalign(zero_size, CACHELINE_SIZE);

4
tools/testing/selftests/powerpc/security/flush_utils.h
View file

@ -9,6 +9,10 @@
#define CACHELINE_SIZE 128
#define PERF_L1D_READ_MISS_CONFIG ((PERF_COUNT_HW_CACHE_L1D) | \
(PERF_COUNT_HW_CACHE_OP_READ << 8) | \
(PERF_COUNT_HW_CACHE_RESULT_MISS << 16))
void syscall_loop(char *p, unsigned long iterations,
unsigned long zero_size);

2
tools/testing/selftests/powerpc/security/rfi_flush.c
View file

@ -54,7 +54,7 @@ int rfi_flush_test(void)
rfi_flush = rfi_flush_orig;
fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1);
fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
FAIL_IF(fd < 0);
p = (char *)memalign(zero_size, CACHELINE_SIZE);