selftests/powerpc: Skip PROT_SAO test in guests/LPARS

In commit 9b725a90a8f1 ("powerpc/64s: Disallow PROT_SAO in LPARs by
default") PROT_SAO was disabled in guests/LPARs by default. So skip
the test if we are running in a guest to avoid a spurious failure.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200901124653.523182-1-mpe@ellerman.id.au

selftests/powerpc: Update PROT_SAO test to skip ISA 3.1

Since SAO support was removed from ISA 3.1, skip the
prot_sao test if PPC_FEATURE2_ARCH_3_1 is set.

Signed-off-by: Shawn Anastasio <shawn@anastas.io>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200821185558.35561-4-shawn@anastas.io

Revert "powerpc/64s: Remove PROT_SAO support"

This reverts commit 5c9fa16e8abd342ce04dc830c1ebb2a03abf6c05.

Since PROT_SAO can still be useful for certain classes of software,
reintroduce it. Concerns about guest migration for LPARs using SAO
will be addressed next.

Signed-off-by: Shawn Anastasio <shawn@anastas.io>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200821185558.35561-2-shawn@anastas.io

powerpc/64s: Remove PROT_SAO support

ISA v3.1 does not support the SAO storage control attribute required to
implement PROT_SAO. PROT_SAO was used by specialised system software
(Lx86) that has been discontinued for about 7 years, and is not thought
to be used elsewhere, so removal should not cause problems.

We rather remove it than keep support for older processors, because
live migrating guest partitions to newer processors may not be possible
if SAO is in use (or worse allowed with silent races).

- PROT_SAO stays in the uapi header so code using it would still build.
- arch_validate_prot() is removed, the generic version rejects PROT_SAO
so applications would get a failure at mmap() time.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Drop KVM change for the time being]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200703011958.1166620-3-npiggin@gmail.com

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: Add a test for PROT_SAO

PROT_SAO is a powerpc-specific flag to mmap(), and we rely on arch
specific logic to allow it to be passed to mmap().

Add a small test to ensure mmap() accepts PROT_SAO. We don't have a good
way to test that it actually causes the mapping to be created with the
right flags, so for now we just touch the mapping so it's faulted in. In
future we might be able to do something better.

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