[ Upstream commit c44f15c1c09481d50fd33478ebb5b8284f8f5edb ]

Add 'volatile' to iounmap()'s argument to prevent build warnings.
This make it the same as other major architectures.

Placates these warnings: (12 such warnings)

../drivers/video/fbdev/riva/fbdev.c: In function 'rivafb_probe':
../drivers/video/fbdev/riva/fbdev.c:2067:42: error: passing argument 1 of 'iounmap' discards 'volatile' qualifier from pointer target type [-Werror=discarded-qualifiers]
 2067 |                 iounmap(default_par->riva.PRAMIN);

Fixes: 1162b0701b14b ("ARC: I/O and DMA Mappings")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

commit 4fd9df10cb7a9289fbd22d669f9f98164d95a1ce upstream.

Since commit d9820ff ("ARC: mm: switch pgtable_t back to struct page *")
a memory leakage problem occurs. Memory allocated for page table entries
not released during process termination. This issue can be reproduced by
a small program that allocates a large amount of memory. After several
runs, you'll see that the amount of free memory has reduced and will
continue to reduce after each run. All ARC CPUs are effected by this
issue. The issue was introduced since the kernel stable release v5.15-rc1.

As described in commit d9820ff after switch pgtable_t back to struct
page *, a pointer to "struct page" and appropriate functions are used to
allocate and free a memory page for PTEs, but the pmd_pgtable macro hasn't
changed and returns the direct virtual address from the PMD (PGD) entry.
Than this address used as a parameter in the __pte_free() and as a result
this function couldn't release memory page allocated for PTEs.

Fix this issue by changing the pmd_pgtable macro and returning pointer to
struct page.

Fixes: d9820ff76f95 ("ARC: mm: switch pgtable_t back to struct page *")
Cc: Mike Rapoport <rppt@kernel.org>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Pavel Kozlov <pavel.kozlov@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In the big pgtable header split, I inadvertently introduced a couple of
duplicate symbols.

Fixes: fe6cb7b043b69cd9 ("ARC: mm: disintegrate pgtable.h into levels and flags")
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

Pull ARC updates from Vineet Gupta:
 "Finally a big pile of changes for ARC (atomics/mm). These are from our
  internal arc64 tree, preparing mainline for eventual arc64 support.
  I'm spreading them out to avoid tsunami of patches in one release.

   - MM rework:
       - Implement up to 4 paging levels
       - Enable STRICT_MM_TYPECHECK
       - switch pgtable_t back to 'struct page *'

   - Atomics rework / implement relaxed accessors

   - Retire legacy MMUv1,v2; ARC750 cores

   - A few other build errors, typos"

* tag 'arc-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (33 commits)
  ARC: mm: vmalloc sync from kernel to user table to update PMD ...
  ARC: mm: support 4 levels of page tables
  ARC: mm: support 3 levels of page tables
  ARC: mm: switch to asm-generic/pgalloc.h
  ARC: mm: switch pgtable_t back to struct page *
  ARC: mm: hack to allow 2 level build with 4 level code
  ARC: mm: disintegrate pgtable.h into levels and flags
  ARC: mm: disintegrate mmu.h (arcv2 bits out)
  ARC: mm: move MMU specific bits out of entry code ...
  ARC: mm: move MMU specific bits out of ASID allocator
  ARC: mm: non-functional code movement/cleanup
  ARC: mm: pmd_populate* to use the canonical set_pmd (and drop pmd_set)
  ARC: ioremap: use more commonly used PAGE_KERNEL based uncached flag
  ARC: mm: Enable STRICT_MM_TYPECHECKS
  ARC: mm: Fixes to allow STRICT_MM_TYPECHECKS
  ARC: mm: move mmu/cache externs out to setup.h
  ARC: mm: remove tlb paranoid code
  ARC: mm: use SCRATCH_DATA0 register for caching pgdir in ARCv2 only
  ARC: retire MMUv1 and MMUv2 support
  ARC: retire ARC750 support
  ...

Pull asm-generic updates from Arnd Bergmann:
 "The main content for 5.15 is a series that cleans up the handling of
  strncpy_from_user() and strnlen_user(), removing a lot of slightly
  incorrect versions of these in favor of the lib/strn*.c helpers that
  implement these correctly and more efficiently.

  The only architectures that retain a private version now are mips,
  ia64, um and parisc. I had offered to convert those at all, but Thomas
  Bogendoerfer wanted to keep the mips version for the moment until he
  had a chance to do regression testing.

  The branch also contains two patches for bitops and for ffs()"

* tag 'asm-generic-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  bitops/non-atomic: make @nr unsigned to avoid any DIV
  asm-generic: ffs: Drop bogus reference to ffz location
  asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols
  asm-generic: remove extra strn{cpy_from,len}_user declarations
  asm-generic: uaccess: remove inline strncpy_from_user/strnlen_user
  s390: use generic strncpy/strnlen from_user
  microblaze: use generic strncpy/strnlen from_user
  csky: use generic strncpy/strnlen from_user
  arc: use generic strncpy/strnlen from_user
  hexagon: use generic strncpy/strnlen from_user
  h8300: remove stale strncpy_from_user
  asm-generic/uaccess.h: remove __strncpy_from_user/__strnlen_user

Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

ARCv2 MMU is software walked and Linux implements 2 levels of paging: pgd/pte.
Forthcoming hw will have multiple levels, so this change preps mm code
for same. It is also fun to try multi levels even on soft-walked code to
ensure generic mm code is robust to handle.

overview
________

2 levels {pgd, pte} : pmd is folded but pmd_* macros are valid and operate on pgd
3 levels {pgd, pmd, pte}:
  - pud is folded and pud_* macros point to pgd
  - pmd_* macros operate on actual pmd

code changes
____________

1. #include <asm-generic/pgtable-nopud.h>

2. Define CONFIG_PGTABLE_LEVELS 3

3a. Define PMD_SHIFT, PMD_SIZE, PMD_MASK, pmd_t
3b. Define pmd_val() which actually deals with pmd
    (pmd_offset(), pmd_index() are provided by generic code)
3c. pmd_alloc_one()/pmd_free() also provided by generic code
    (pmd_populate/pmd_free already exist)

4. Define pud_none(), pud_bad() macros based on generic pud_val() which
   internally pertains to pgd now.
4b. define pud_populate() to just setup pgd

Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

With previous patch ARC pgalloc functions are same as generic, hence
switch to that.

Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

So far ARC pgtable_t has not been struct page based to avoid extra
page_address() calls involved. However the differences are down to
noise and get in the way of using generic code, hence this patch.

This also allows us to reuse generic THP depost/withdraw code.

There's some additional consideration for PGDIR_SHIFT in 4K page config.
Now due to page tables being PAGE_SIZE deep only, the address split
can't be really arbitrary.

Tested-by: kernel test robot <lkp@intel.com>
Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>

 - pgtable-bits-arcv2.h (MMU specific page table flags)
 - pgtable-levels.h (paging levels)

No functional changes, but paves way for easy addition of new MMU code
with different bits and levels etc

Signed-off-by: Vineet Gupta <vgupta@kernel.org>