selftests: Skip TM tests on synthetic TM implementations

Transactional Memory was removed from the architecture in ISA v3.1. For
threads running in P8/P9 compatibility mode on P10 a synthetic TM
implementation is provided. In this implementation, tbegin. always sets
cr0 eq meaning the abort handler is always called. This is not an issue
as users of TM are expected to have a fallback non transactional way to
make forward progress in the abort handler. The TEXASR indicates if a
transaction failure is due to a synthetic implementation.

Some of the TM self tests need a non-degenerate TM implementation for
their testing to be meaningful so check for a synthetic implementation
and skip the test if so.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210729041317.366612-2-jniethe5@gmail.com

selftests/powerpc: Fix and enhance TM signal context tests

Currently TM signal context tests for GPR, FPR, VMX, and VSX registers
print wrong register numbers (wrongly starting from register 0 instead
of the first register in the non-volatile subset). Besides it the
output when a mismatch happens is poor giving not much information
about which context and which register mismatches, because it prints
both contexts at the same time and not a comparison between the value
that mismatches and the value expected and, moreover, it stops
printing on the first mismatch, but it's important to know if there
are other mismatches happening beyond the first one.

For instance, this is the current output when a mismatch happens:

test: tm_signal_context_chk_gpr
tags: git_version:v5.2-8249-g02e970fae465-dirty
Failed on 0 GPR 1 or 18446744073709551615
failure: tm_signal_context_chk_gpr

test: tm_signal_context_chk_fpu
tags: git_version:v5.2-8248-g09c289e3ef80
Failed on 0 FP -1 or -1
failure: tm_signal_context_chk_fpu

test: tm_signal_context_chk_vmx
tags: git_version:v5.2-8248-g09c289e3ef80
Failed on 0 vmx 0xfffffffffffffffefffffffdfffffffc vs 0xfffffffffffffffefffffffdfffffffc
failure: tm_signal_context_chk_vmx

test: tm_signal_context_chk_vsx
tags: git_version:v5.2-8248-g09c289e3ef80
Failed on 0 vsx 0xfffffffffefffffffdfffffffcffffff vs 0xfffffffffefffffffdfffffffcffffff
failure: tm_signal_context_chk_vsx

This commit fixes the register numbers printed and enhances the error
output by providing a full list of mismatching registers separated by
the context (non-speculative or speculative context), for example:

test: tm_signal_context_chk_gpr
tags: git_version:v5.2-8249-g02e970fae465-dirty
GPR14 (1st context) == 1 instead of -1 (expected)
GPR15 (1st context) == 2 instead of -2 (expected)
GPR14 (2nd context) == 0 instead of 18446744073709551615 (expected)
GPR15 (2nd context) == 0 instead of 18446744073709551614 (expected)
failure: tm_signal_context_chk_gpr

test: tm_signal_context_chk_fpu
tags: git_version:v5.2-8249-g02e970fae465-dirty
FPR14 (1st context) == -1 instead of 1 (expected)
FPR15 (1st context) == -2 instead of 2 (expected)
failure: tm_signal_context_chk_fpu

test: tm_signal_context_chk_vmx
tags: git_version:v5.2-8249-g02e970fae465-dirty
VMX20 (1st context) == 0xfffffffffffffffefffffffdfffffffc instead of 0x00000001000000020000000300000004 (expected)
VMX21 (1st context) == 0xfffffffbfffffffafffffff9fffffff8 instead of 0x00000005000000060000000700000008 (expected)
failure: tm_signal_context_chk_vmx

test: tm_signal_context_chk_vsx
tags: git_version:v5.2-8249-g02e970fae465-dirty
VSX20 (1st context) == 0xfffffffffefffffffdfffffffcffffff instead of 0x00000001000000020000000300000004 (expected)
VSX21 (1st context) == 0xfbfffffffafffffff9fffffff8ffffff instead of 0x00000005000000060000000700000008 (expected)
failure: tm_signal_context_chk_vsx

Finally, this commit adds comments to the tests in the hope that it
will help people not so familiar with TM understand the tests.

Signed-off-by: Gustavo Romero <gromero@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190814205211.24840-1-gromero@linux.ibm.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

selftests/powerpc: Add checks for transactional FPUs in signal contexts

If a thread receives a signal while transactional the kernel creates a
second context to show the transactional state of the process. This
test loads some known values and waits for a signal and confirms that
the expected values are in the signal context.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>