s390/nmi: implement and use local_mcck_save() / local_mcck_restore()

Instead of using local_mcck_disable() / local_mcck_enable() implement and
use local_mcck_save() / local_mcck_restore() to disable machine checks, and
restoring the previous state.

The problem with using local_mcck_disable() / local_mcck_enable() is that
there is an assumption that machine checks are always enabled. While this
is currently the case the code still looks quite odd, readers need to
double check if the code is correct.

In order to increase readability save and then restore the old machine
check mask bit, instead of assuming that it must have been enabled.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

s390/kprobes: replace kretprobe with rethook

That's an adaptation of commit f3a112c0c40d ("x86,rethook,kprobes:
Replace kretprobe with rethook on x86") to s390.

Replaces the kretprobe code with rethook on s390. With this patch,
kretprobe on s390 uses the rethook instead of kretprobe specific
trampoline code.

Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390: current_stack_pointer shouldn't be a function

s390 defines current_stack_pointer as function while all other
architectures use 'register unsigned long asm("<stackptr reg>").

This make codes like the following from check_stack_object() fail:

if (IS_ENABLED(CONFIG_STACK_GROWSUP)) {
if ((void *)current_stack_pointer < obj + len)
return BAD_STACK;
} else {
if (obj < (void *)current_stack_pointer)
return BAD_STACK;
}

because this would compare the address of current_stack_pointer() and
not the stackpointer value.

Reported-by: Karsten Graul <kgraul@linux.ibm.com>
Fixes: 2792d84e6da5 ("usercopy: Check valid lifetime via stack depth")
Cc: Kees Cook <keescook@chromium.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/test_unwind: verify __kretprobe_trampoline is replaced

Reviewed-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: extend kretprobe test

Verify unwinding from kretprobed function.

Reviewed-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: add kretprobe tests

Add tests to verify that s390 kretprobes maintain a correct stack
chain and ensure their proper function.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: avoid build warning with W=1

Fix the following build warning with W=1

arch/s390/lib/test_unwind.c:172:21: warning: variable 'fops' set but not used [-Wunused-but-set-variable]
struct ftrace_ops *fops;

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: fix and extend kprobes test

Running kprobe test on a kernel built with clang 14 didn't actually
trigger pgm_pre_handler() and no unwinder code was called. Even though
do_report_trap() is a global symbol, clang inlined it in several local
functions including illegal_op() handler, so that kprobbing a global
symbol didn't have a desired effect.

To achieve the same test result (unwinding from a program check
handler) introduce a local function and probe an instruction in the
middle, so that kprobe doesn't take KPROBE_ON_FTRACE path.

While at it, add another test for KPROBE_ON_FTRACE.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: add ftrace test

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: add "backtrace" module parameter

By default no backtraces are printed when a test succeeds, but sometimes
it is useful to spot issues automated test doesn't cover. Add "backtrace"
module parameter to force it.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: minor cleanup

- make current_test static
- use current_test consistently
- add TEST_WITH_FLAGS macro to contract parametrized tests definition

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: show tests as skipped if unsupported

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: use raw opcode instead of invalid instruction

Building with clang & LLVM_IAS=1 leads to an error:
arch/s390/lib/test_unwind.c:179:4: error: invalid register pair
" mvcl %%r1,%%r1\n"
^

The test creates an invalid instruction that would trap at runtime, but the
LLVM inline assembler tries to validate it at compile time too.

Use the raw instruction opcode instead.

Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1421
Link: https://lore.kernel.org/r/20211117174822.3632412-1-ilie.halip@gmail.com
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[hca@linux.ibm.com: use illegal opcode, and update comment]
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/test_unwind: convert to KUnit

Modified stack unwinder self tests to use kunit framework. The
functionality stayed the same but the output format is now in tap13
format.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/lib: use call_on_stack() macro

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: print test suite start/end info

Add couple of additional info lines to make it easier to match
test suite output and results.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/test_unwind: add WARN if tests failed

Trigger a warning if any of unwinder tests fail. This should help to
prevent quiet ignoring of test results when panic_on_warn is enabled.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/test_unwind: unify error handling paths

Handle the case of "unwind state reliable but addr is 0" like other error
cases in this function and trigger output of failing stacktrace to aid
debugging.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/test_unwind: use timer instead of udelay

Instead of registering an external interrupt handler and relying on
the udelay implementation, simply use a timer to get into irq context.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/test_unwind: fix CALL_ON_STACK tests

The CALL_ON_STACK tests use the no_dat stack to switch to a different
stack for unwinding tests. If an interrupt or machine check happens
while using that stack, and previously being on the async stack, the
interrupt / machine check entry code (SWITCH_ASYNC) will assume that
the previous context did not use the async stack and happily use the
async stack again.

This will lead to stack corruption of the previous context.

To solve this disable both interrupts and machine checks before
switching to the no_dat stack.

Fixes: 7868249fbbc8 ("s390/test_unwind: add CALL_ON_STACK tests")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/test_unwind: fix possible memleak in test_unwind()

test_unwind() misses to call kfree(bt) in an error path.
Add the missed function call to fix it.

Fixes: 0610154650f1 ("s390/test_unwind: print verbose unwinding results")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

iov_iter: Move unnecessary inclusion of crypto/hash.h

The header file linux/uio.h includes crypto/hash.h which pulls in
most of the Crypto API. Since linux/uio.h is used throughout the
kernel this means that every tiny bit of change to the Crypto API
causes the entire kernel to get rebuilt.

This patch fixes this by moving it into lib/iov_iter.c instead
where it is actually used.

This patch also fixes the ifdef to use CRYPTO_HASH instead of just
CRYPTO which does not guarantee the existence of ahash.

Unfortunately a number of drivers were relying on linux/uio.h to
provide access to linux/slab.h. This patch adds inclusions of
linux/slab.h as detected by build failures.

Also skbuff.h was relying on this to provide a declaration for
ahash_request. This patch adds a forward declaration instead.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

s390/test_unwind: fix spelling mistake "reqister" -> "register"

There is a spelling mistake in a pr_info message. Fix it.

Link: https://lkml.kernel.org/r/20191202090215.28766-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: add program check context tests

Add unwinding from program check handler tests. Unwinder should be able
to unwind through pt_regs stored by program check handler on task stack.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: add irq context tests

Add unwinding from irq context tests. Unwinder should be able to unwind
through irq stack to task stack up to task pt_regs.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: print verbose unwinding results

Add stack name, sp and reliable information into test unwinding
results. Also consider ip outside of kernel text as failure if the
state is reported reliable.

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: add CALL_ON_STACK tests

Add CALL_ON_STACK helper testing. Tests make sure that we can unwind from
switched stack to original one up to task pt_regs (nodat -> task stack).

UWM_SWITCH_STACK could not be used together with UWM_THREAD because
get_stack_info explicitly restricts unwinding to task stack if
task != current.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/test_unwind: require that unwinding ended successfully

Currently unwinder test passes if unwinding results contain unwindme_func2
and unwindme_func1 functions.
Now that unwinder reports success upon reaching task pt_regs, check
that unwinding ended successfully in every test.

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/unwind: add a test for the internal API

unwind_for_each_frame can take at least 8 different sets of parameters.
Add a test to make sure they all are handled in a sane way.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Co-developed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>