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: d9820ff76f ("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>
They were in <asm/pgtables.h> and have been removed from there in
974b9b2c68 ("mm: consolidate pte_index() and pte_offset_*() definitions")
in favor of the generic version. But that missed that the same definitons
also existed in <asm/pgtable-levels.h>, where they were (inadvertently?)
introduced in fe6cb7b043 ("ARC: mm: disintegrate pgtable.h into levels
and flags").
Fixes: 974b9b2c68 ("mm: consolidate pte_index() and pte_offset_*() definitions")
Fixes: fe6cb7b043 ("ARC: mm: disintegrate pgtable.h into levels and flags")
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
We need to use this function in common code, so define it for
architectures and/or configrations that miss it. The result of
pmd_pfn() will only be used if TRANSPARENT_HUGEPAGE is enabled,
but a function or macro called pmd_pfn() must be defined, even
on machines with two level page tables.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.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>
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>
