mm, treewide: introduce NR_PAGE_ORDERS

NR_PAGE_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total.

NR_PAGE_ORDERS assists in defining arrays of page orders and allows for
more natural iteration over them.

[kirill.shutemov@linux.intel.com: fixup for kerneldoc warning]
Link: https://lkml.kernel.org/r/20240101111512.7empzyifq7kxtzk3@box
Link: https://lkml.kernel.org/r/20231228144704.14033-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/test_meminit: allocate pages up to order MAX_ORDER

test_pages() tests the page allocator by calling alloc_pages() with
different orders up to order 10.

However, different architectures and platforms support different maximum
contiguous allocation sizes. The default maximum allocation order
(MAX_ORDER) is 10, but architectures can use CONFIG_ARCH_FORCE_MAX_ORDER
to override this. On platforms where this is less than 10, test_meminit()
will blow up with a WARN(). This is expected, so let's not do that.

Replace the hardcoded "10" with the MAX_ORDER macro so that we test
allocations up to the expected platform limit.

Link: https://lkml.kernel.org/r/20230714015238.47931-1-ajd@linux.ibm.com
Fixes: 5015a300a522 ("lib: introduce test_meminit module")
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Xiaoke Wang <xkernel.wang@foxmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/test_meminit: add checks for the allocation functions

alloc_pages(), kmalloc() and vmalloc() are all memory allocation functions
which can return NULL when some internal memory failures happen. So it is
better to check the return of them to catch the failure in time for better
test them.

Link: https://lkml.kernel.org/r/tencent_D44A49FFB420EDCCBFB9221C8D14DFE12908@qq.com
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/test_meminit: optimize do_kmem_cache_rcu_persistent() test

To make the test more robust, there are the following changes:
1. add a check for the return value of kmem_cache_alloc().
2. properly release the object `buf` on several error paths.
3. release the objects of `used_objects` if we never hit `saved_ptr`.
4. destroy the created cache by default.

Link: https://lkml.kernel.org/r/tencent_7CB95F1C3914BCE1CA4A61FF7C20E7CCB108@qq.com
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Xiaoke Wang <xkernel.wang@foxmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/test_meminit: destroy cache in kmem_cache_alloc_bulk() test

Make do_kmem_cache_size_bulk() destroy the cache it creates.

Link: https://lkml.kernel.org/r/aced20a94bf04159a139f0846e41d38a1537debb.1640018297.git.andreyknvl@google.com
Fixes: 03a9349ac0e0 ("lib/test_meminit: add a kmem_cache_alloc_bulk() test")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_meminit.c: add bulk alloc/free tests

kmem_cache_alloc_bulk/kmem_cache_free_bulk are used to make multiple
allocations of the same size to avoid the overhead of multiple
kmalloc/kfree calls. Extend the kmem_cache tests to make some calls to
these APIs.

Link: http://lkml.kernel.org/r/20191107191447.23058-1-labbott@redhat.com
Signed-off-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Alexander Potapenko <glider@google.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Sandeep Patil <sspatil@android.com>
Cc: Jann Horn <jannh@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_meminit: add a kmem_cache_alloc_bulk() test

Make sure allocations from kmem_cache_alloc_bulk() and
kmem_cache_free_bulk() are properly initialized.

Link: http://lkml.kernel.org/r/20191007091605.30530-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Thibaut Sautereau <thibaut@sautereau.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_meminit.c: use GFP_ATOMIC in RCU critical section

kmalloc() shouldn't sleep while in RCU critical section, therefore use
GFP_ATOMIC instead of GFP_KERNEL.

The bug was spotted by the 0day kernel testing robot.

Link: http://lkml.kernel.org/r/20190725121703.210874-1-glider@google.com
Fixes: 7e659650cbda ("lib: introduce test_meminit module")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_meminit.c: minor test fixes

Fix the following issues in test_meminit.c:
- |size| in fill_with_garbage_skip() should be signed so that it
doesn't overflow if it's not aligned on sizeof(*p);
- fill_with_garbage_skip() should actually skip |skip| bytes;
- do_kmem_cache_size() should deallocate memory in the RCU case.

Link: http://lkml.kernel.org/r/20190626133135.217355-1-glider@google.com
Fixes: 7e659650cbda ("lib: introduce test_meminit module")
Fixes: 94e8988d91c7 ("lib/test_meminit.c: fix -Wmaybe-uninitialized false positive")
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_meminit.c: fix -Wmaybe-uninitialized false positive

The conditional logic is too complicated for the compiler to fully
comprehend:

lib/test_meminit.c: In function 'test_meminit_init':
lib/test_meminit.c:236:5: error: 'buf_copy' may be used uninitialized in this function [-Werror=maybe-uninitialized]
kfree(buf_copy);
^~~~~~~~~~~~~~~
lib/test_meminit.c:201:14: note: 'buf_copy' was declared here

Simplify it by splitting out the non-rcu section.

Link: http://lkml.kernel.org/r/20190617131210.2190280-1-arnd@arndb.de
Fixes: af734ee6ec85 ("lib: introduce test_meminit module")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: introduce test_meminit module

Add tests for heap and pagealloc initialization. These can be used to
check init_on_alloc and init_on_free implementations as well as other
approaches to initialization.

Expected test output in the case the kernel provides heap initialization
(e.g. when running with either init_on_alloc=1 or init_on_free=1):

test_meminit: all 10 tests in test_pages passed
test_meminit: all 40 tests in test_kvmalloc passed
test_meminit: all 60 tests in test_kmemcache passed
test_meminit: all 10 tests in test_rcu_persistent passed
test_meminit: all 120 tests passed!

Link: http://lkml.kernel.org/r/20190529123812.43089-4-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Sandeep Patil <sspatil@android.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>