[PATCH] powerpc/mm/book3s64/hash/4k: Add pmd_same callback for 4K page size

[Michael Ellerman]

On Thu, 06 Jul 2023 07:54:05 +0530, Aneesh Kumar K.V wrote:
> With commit 0d940a9b270b ("mm/pgtable: allow pte_offset_map[_lock]() to
> fail") the kernel is now using pmd_same to compare pmd values that are
> pointing to a level 4 page table page. Move the functions out of #ifdef
> CONFIG_TRANSPARENT_HUGEPAGE and add a variant that can work with both 4K
> and 64K page size.
> 
> kernel BUG at arch/powerpc/include/asm/book3s/64/hash-4k.h:141!
> Oops: Exception in kernel mode, sig: 5 [#1]
> LE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
> .....
> NIP [c00000000048aee0] __pte_offset_map_lock+0xf0/0x164
> LR [c00000000048ae78] __pte_offset_map_lock+0x88/0x164
> Call Trace:
>  0xc0003f000009a340 (unreliable)
>  __handle_mm_fault+0x1340/0x1980
>  handle_mm_fault+0xbc/0x380
>  __get_user_pages+0x320/0x550
>  get_user_pages_remote+0x13c/0x520
>  get_arg_page+0x80/0x1d0
>  copy_string_kernel+0xc8/0x250
>  kernel_execve+0x11c/0x270
>  run_init_process+0xe4/0x10c
>  kernel_init+0xbc/0x1a0
>  ret_from_kernel_user_thread+0x14/0x1c
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/mm/book3s64/hash/4k: Add pmd_same callback for 4K page size
      https://git.kernel.org/powerpc/c/cf53564b11cef5cdfafc548b172345c9aa753f89

cheers