selftests/powerpc/dexcr: Add hashst/hashchk test

Test the kernel DEXCR[NPHIE] interface and hashchk exception handling.

Introduces with it a DEXCR utils library for common DEXCR operations.

Volatile is used to prevent the compiler optimising away the signal
tests.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230616034846.311705-11-bgray@linux.ibm.com

selftests/powerpc: Allow bind_to_cpu() to automatically pick CPU

All current users of bind_to_cpu() don't care _which_ CPU they get, just
that they are bound to a single free one. So alter the interface to

1. Accept a BIND_CPU_ANY value that tells it to automatically
pick a CPU
2. Return the picked CPU

And convert all these users to bind_to_cpu(BIND_CPU_ANY).

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230406043320.125138-4-bgray@linux.ibm.com

selftests/powerpc: Move bind_to_cpu() to utils.h

This function will be useful in the DSCR test patches later in this
series, so promote it to be shared by all powerpc selftests.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230406043320.125138-3-bgray@linux.ibm.com

selftests/powerpc: Add automatically allocating read_file

A couple of tests roll their own auto-allocating file read logic.

Add a generic implementation and convert them to use it.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230203003947.38033-6-bgray@linux.ibm.com

selftests/powerpc: Add {read,write}_{long,ulong}

Add helper functions to read and write (unsigned) long values directly
from/to files. One of the kernel interfaces uses hex strings, so we need
to allow passing a base too.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230203003947.38033-5-bgray@linux.ibm.com

selftests/powerpc: Parse long/unsigned long value safely

Often a file is expected to hold an integral value. Existing functions
will use a C stdlib function like atoi or strtol to parse the file.
These operations are error prone, with complicated error conditions
(atoi returns 0 if not a number, and is undefined behaviour if not in
range. strtol returns 0 if not a number, and LONG_MIN/MAX if not in
range + sets errno to ERANGE).

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230203003947.38033-4-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

selftests/powerpc: Add generic read/write file util

File read/write is reimplemented in about 5 different ways in the
various PowerPC selftests. This indicates it should be a common util.

Add a common read_file / write_file implementation and convert users
to it where (easily) possible.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230203003947.38033-2-bgray@linux.ibm.com

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

selftests/powerpc: Make using_hash_mmu() work on Cell & PowerMac

These platforms don't show the MMU in /proc/cpuinfo, but they always
use hash, so teach using_hash_mmu() that.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200819015727.1977134-1-mpe@ellerman.id.au

selftests/powerpc: Fix online CPU selection

The size of the CPU affinity mask must be large enough for
systems with a very large number of CPUs. Otherwise, tests
which try to determine the first online CPU by calling
sched_getaffinity() will fail. This makes sure that the size
of the allocated affinity mask is dependent on the number of
CPUs as reported by get_nprocs_conf().

Fixes: 3752e453f6ba ("selftests/powerpc: Add tests of PMU EBBs")
Reported-by: Shirisha Ganta <shiganta@in.ibm.com>
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a408c4b8e9a23bb39b539417a21eb0ff47bb5127.1596084858.git.sandipan@linux.ibm.com

selftests/powerpc: Move Hash MMU check to utilities

This moves a function to test if the MMU is in Hash mode
under the generic test utilities.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200604125610.649668-3-sandipan@linux.ibm.com

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

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 191

Based on 1 normalized pattern(s):

licensed under gplv2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 99 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170027.163048684@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

selftests/powerpc: Fix compilation issue due to asm label

We are using 'dscr_insn' as a label in inline asm to identify if a
SIGILL was generated by the mtspr instruction at that point. However,
with inline assembly, the compiler is still free to duplicate the asm
statement for optimization purposes, which results in the label being
defined twice with the error:
/tmp/ccerQCql.s:874: Error: symbol `dscr_insn' is already defined

With different compiler versions, we may also see:
/tmp/ccJzLDlN.o:(.toc+0x0): undefined reference to `dscr_insn'

Remove the use of the label in the inline assembly. Instead, just look
for the offending instruction in the signal handler.

Fixes: d2bf793237b3 ("selftests/powerpc: Add test to verify rfi flush across a system call")
Reported-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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>

selftests/powerpc: Add a helper for checking if we're on ppc64le

Some of our selftests have only been tested on ppc64le and crash or
behave weirdly on ppc64/ppc32. So add a helper for checking the UTS
machine.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

selftests/powerpc: Refactor the AUXV routines

Refactor the AUXV routines so they are more composable. In a future test
we want to look for many AUXV entries and we don't want to have to read
/proc/self/auxv each time.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

selftests/powerpc: Move pick_online_cpu() up into utils.c

We want to use this in another test, so make it available at the top of
the powerpc selftests tree.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

selftests/powerpc: Move get_auxv_entry() into utils.c

This doesn't really belong in harness.c, it's a helper function. So move
it into utils.c.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>