In reaction to a proposal to introduce a memcpy_mcsafe_fast()
implementation Linus points out that memcpy_mcsafe() is poorly named
relative to communicating the scope of the interface. Specifically what
addresses are valid to pass as source, destination, and what faults /
exceptions are handled.
Of particular concern is that even though x86 might be able to handle
the semantics of copy_mc_to_user() with its common copy_user_generic()
implementation other archs likely need / want an explicit path for this
case:
On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > However now I see that copy_user_generic() works for the wrong reason.
> > It works because the exception on the source address due to poison
> > looks no different than a write fault on the user address to the
> > caller, it's still just a short copy. So it makes copy_to_user() work
> > for the wrong reason relative to the name.
>
> Right.
>
> And it won't work that way on other architectures. On x86, we have a
> generic function that can take faults on either side, and we use it
> for both cases (and for the "in_user" case too), but that's an
> artifact of the architecture oddity.
>
> In fact, it's probably wrong even on x86 - because it can hide bugs -
> but writing those things is painful enough that everybody prefers
> having just one function.
Replace a single top-level memcpy_mcsafe() with either
copy_mc_to_user(), or copy_mc_to_kernel().
Introduce an x86 copy_mc_fragile() name as the rename for the
low-level x86 implementation formerly named memcpy_mcsafe(). It is used
as the slow / careful backend that is supplanted by a fast
copy_mc_generic() in a follow-on patch.
One side-effect of this reorganization is that separating copy_mc_64.S
to its own file means that perf no longer needs to track dependencies
for its memcpy_64.S benchmarks.
[ bp: Massage a bit. ]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com
Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
Introduce tests to cover simple scenarios where user is watching
memory which can be accessed by kernel as well. We also support
_MODE_EXACT with _SETHWDEBUG interface. Move those testcases outside
of _BP_RANGE condition. This will help to test _MODE_EXACT scenarios
when CONFIG_HAVE_HW_BREAKPOINT is not set, eg:
$ ./ptrace-hwbreak
...
PTRACE_SET_DEBUGREG, Kernel Access Userspace, len: 8: Ok
PPC_PTRACE_SETHWDEBUG, MODE_EXACT, WO, len: 1: Ok
PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RO, len: 1: Ok
PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RW, len: 1: Ok
PPC_PTRACE_SETHWDEBUG, MODE_EXACT, Kernel Access Userspace, len: 1: Ok
success: ptrace-hwbreak
Suggested-by: Pedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902042945.129369-9-ravi.bangoria@linux.ibm.com
The signal handler in the alignment handler self test has the ability
to jump over the instruction that triggered the signal. It does this
by incrementing the PT_NIP in the user context by 4. If it were a
prefixed instruction this will mean that the suffix is then executed
which is incorrect. Instead check if the major opcode indicates a
prefixed instruction (e.g. it is 1) and if so increment PT_NIP by 8.
If ISA v3.1 is not available treat it as a word instruction even if
the major opcode is 1.
Fixes: 620a6473df ("selftests/powerpc: Add prefixed loads/stores to alignment_handler test")
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Fix 32-bit build, rename haveprefixes to prefixes_enabled]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200824131231.14008-1-jniethe5@gmail.com
If we're running on a CPU without VMX/VSX then don't touch them. This
is fragile, the compiler could spill a VMX/VSX register and break the
test anyway. But in practice it seems to work, ie. the test runs to
completion on a system without VSX with this change.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200819015727.1977134-8-mpe@ellerman.id.au
This test creates some threads, which write to TM SPRs, and then makes
sure the registers maintain the correct values across context switches
and contention with other threads.
But currently the test finishes almost instantaneously, which reduces
the chance of it hitting an interesting condition.
So increase the number of loops, so it runs a bit longer, though still
less than 2s on a Power8.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200813013445.686464-3-mpe@ellerman.id.au
This test tries to set affinity to CPUs that don't exist, especially
if the set of online CPUs doesn't start at 0.
But there's no real reason for it to use setaffinity in the first
place, it's just trying to create lots of threads to cause contention.
So drop the setaffinity entirely.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200813013445.686464-2-mpe@ellerman.id.au
On distros using older glibc versions, the pkey tests encounter build
failures due to redefinition of the pkey syscall numbers.
For compatibility, commit 743f3544ff added a wrapper for the
gettid() syscall and included syscall.h if the version of glibc used
is older than 2.30. This leads to different definitions of SYS_pkey_*
as the ones in the pkey test header set numeric constants where as the
ones from syscall.h reuse __NR_pkey_*. The compiler complains about
redefinitions since they are different.
This replaces SYS_pkey_* definitions with __NR_pkey_* such that the
definitions in both syscall.h and pkeys.h are alike. This way, if
syscall.h has to be included for compatibility reasons, builds will
still succeed.
Fixes: 743f3544ff ("selftests/powerpc: Add wrapper for gettid")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Suggested-by: David Laight <david.laight@aculab.com>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a4956d838bf59b0a71a2553c5ca81131ea8b49b9.1596561758.git.sandipan@linux.ibm.com
Some of our tests use VSX or newer VMX instructions, so need to be
skipped on older CPUs to avoid SIGILL'ing.
Similarly TAR was added in v2.07, and the PMU event used in the stcx
fail test only works on Power8 or later.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200803020719.96114-1-mpe@ellerman.id.au
When running under older versions of qemu of under newer versions with
old machine types, some security features will not be reported to the
guest. This will lead the guest OS to consider itself Vulnerable to
spectre_v2.
So, spectre_v2 test fails in such cases when the host is mitigated and
miss predictions cannot be detected as expected by the test.
Make it return the skip code instead, for this particular case. We
don't want to miss the case when the test fails and the system reports
as mitigated or not affected. But it is not a problem to miss failures
when the system reports as Vulnerable.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200728155039.401445-1-cascardo@canonical.com
We have custom stack expansion checks that it turns out are extremely
badly tested and contain bugs, surprise. So add some tests that
exercise the code and capture the current boundary conditions.
The signal test currently fails on 64-bit kernels because the 2048
byte allowance for the signal frame is too small, we will fix that in
a subsequent patch.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724092528.1578671-1-mpe@ellerman.id.au
For drivers that don't have the error handling callbacks we implement
recovery by removing the device and re-probing it. This causes the sysfs
directory for the PCI device to be removed which causes the following
spurious error to be printed when checking the PE state:
Breaking 0005:03:00.0...
./eeh-basic.sh: line 13: can't open /sys/bus/pci/devices/0005:03:00.0/eeh_pe_state: no such file
0005:03:00.0, waited 0/60
0005:03:00.0, waited 1/60
0005:03:00.0, waited 2/60
0005:03:00.0, waited 3/60
0005:03:00.0, waited 4/60
0005:03:00.0, waited 5/60
0005:03:00.0, waited 6/60
0005:03:00.0, waited 7/60
0005:03:00.0, Recovered after 8 seconds
We currently try to avoid this by checking if the PE state file exists
before reading from it. This is however inherently racy so re-work the
state checking so that we only read from the file once, and we squash any
errors that occur while reading.
Fixes: 85d86c8aa5 ("selftests/powerpc: Add basic EEH selftest")
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200727010127.23698-1-oohall@gmail.com
Commit 192b6a7805 ("powerpc/book3s64/pkeys: Fix
pkey_access_permitted() for execute disable pkey") fixed a
bug that caused repetitive faults for pkeys with no execute
rights alongside some combination of read and write rights.
This removes the last two cases of the test, which check
the behaviour of pkeys with read, write but no execute
rights and all the rights, in favour of checking all the
possible combinations of read, write and execute rights
to be able to detect bugs like the one mentioned above.
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/db467500f8af47727bba6b35796e8974a78b71e5.1595821792.git.sandipan@linux.ibm.com
Update our memcmp selftest, to test the case where we're comparing up
to the end of a page and the subsequent page is not mapped. We have to
make sure we don't read off the end of the page and cause a fault.
We had a bug there in the past, fixed in commit
d947075739 ("powerpc/64: Fix memcmp reading past the end of src/dest").
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722055315.962391-1-mpe@ellerman.id.au
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
The per_event_excludes test wants to run on Power8 or later. But
currently it checks that AT_BASE_PLATFORM *equals* power8, which means
it only runs on Power8.
Fix it to check for the ISA 2.07 feature, which will be set on Power8
and later CPUs.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200716122142.3776261-1-mpe@ellerman.id.au
ERR_NX_TRANSLATION(CSB.CC=5) is for internal to VAS for fault handling
and should not used by OS. ERR_NX_AT_FAULT(CSB.CC=250) is the proper
error code should be reported by OS when NX encounters address
translation failure.
This patch uses CC=250 to determine the fault address when the request
is not successful.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0315251705baff94f678c33178491b5008723511.camel@linux.ibm.com
An extra count on ebb_state.stats.pmc_count[PMC_INDEX(pmc)] is being per-
formed when count_pmc() is used to reset PMCs on a few selftests. This
extra pmc_count can occasionally invalidate results, such as the ones from
cycles_test shown hereafter. The ebb_check_count() failed with an above
the upper limit error due to the extra value on ebb_state.stats.pmc_count.
Furthermore, this extra count is also indicated by extra PMC1 trace_log on
the output of the cycle test (as well as on pmc56_overflow_test):
==========
...
[21]: counter = 8
[22]: register SPRN_MMCR0 = 0x0000000080000080
[23]: register SPRN_PMC1 = 0x0000000080000004
[24]: counter = 9
[25]: register SPRN_MMCR0 = 0x0000000080000080
[26]: register SPRN_PMC1 = 0x0000000080000004
[27]: counter = 10
[28]: register SPRN_MMCR0 = 0x0000000080000080
[29]: register SPRN_PMC1 = 0x0000000080000004
>> [30]: register SPRN_PMC1 = 0x000000004000051e
PMC1 count (0x280000546) above upper limit 0x2800003e8 (+0x15e)
[FAIL] Test FAILED on line 52
failure: cycles
==========
Signed-off-by: Desnes A. Nunes do Rosario <desnesn@linux.ibm.com>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200626164737.21943-1-desnesn@linux.ibm.com
The Power ISA mandates that all writes to the Authority
Mask Register (AMR) must always be preceded as well as
succeeded by a context synchronizing instruction.
This makes sure that the tests follow this requirement
when attempting to update a pkey's access rights.
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200604125610.649668-2-sandipan@linux.ibm.com
We use OUTPUT directory as TMPOUT for checking no-pie option.
Since commit f2f02ebd8f ("kbuild: improve cc-option to clean up all
temporary files") when building powerpc/ from selftests directory, the
OUTPUT directory points to powerpc/pmu/ebb/ and gets removed when
checking for -no-pie option in try-run routine, subsequently build
fails with the following:
$ make -C powerpc
...
TARGET=ebb; BUILD_TARGET=$OUTPUT/$TARGET; mkdir -p $BUILD_TARGET; make OUTPUT=$BUILD_TARGET -k -C $TARGET all
make[2]: Entering directory '/home/linux-master/tools/testing/selftests/powerpc/pmu/ebb'
make[2]: *** No rule to make target 'Makefile'.
make[2]: Failed to remake makefile 'Makefile'.
make[2]: *** No rule to make target 'ebb.c', needed by '/home/linux-master/tools/testing/selftests/powerpc/pmu/ebb/reg_access_test'.
make[2]: *** No rule to make target 'ebb_handler.S', needed by '/home/linux-master/tools/testing/selftests/powerpc/pmu/ebb/reg_access_test'.
make[2]: *** No rule to make target 'trace.c', needed by '/home/linux-master/tools/testing/selftests/powerpc/pmu/ebb/reg_access_test'.
make[2]: *** No rule to make target 'busy_loop.S', needed by '/home/linux-master/tools/testing/selftests/powerpc/pmu/ebb/reg_access_test'.
make[2]: Target 'all' not remade because of errors.
Fix this by adding a suffix to the OUTPUT directory so that the
failure is avoided.
Fixes: 9686813f6e ("selftests/powerpc: Fix try-run when source tree is not writable")
Signed-off-by: Harish <harish@linux.ibm.com>
[mpe: Mention that commit that triggered the breakage]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200625165721.264904-1-harish@linux.ibm.com
Extend the alignment handler selftest to exercise prefixed load store
instructions. Add tests for prefixed VSX, floating point and integer
instructions.
Skip prefix tests if ISA version does not support prefixed instructions.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Tested-by: Alistair Popple <alistair@popple.id.au>
[mpe: Fixup PPC_FEATURE2_ARCH_3_1 naming as noted by Alistair]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200520021103.19798-2-jniethe5@gmail.com
