On Wed, Oct 09, 2019 at 11:57:31AM -0700, Vineet Gupta wrote:
> Add the intermediate p4d accessors to make it 5 level compliant.
>
> This is a non-functional change anyways since ARC has software page walker
> with 2 lookup levels (pgd -> pte)
>
> There is slight code bloat due to pulling in needless p*d_free_tlb()
> macros which needs to be addressed seperately.
>
> | bloat-o-meter2 vmlinux-with-5LEVEL_HACK vmlinux-patched
> | add/remove: 0/0 grow/shrink: 2/0 up/down: 128/0 (128)
> | function old new delta
> | free_pgd_range 546 656 +110
> | p4d_clear_bad 2 20 +18
> | Total: Before=4137148, After=4137276, chg 0.000000%
>
> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Acked-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> ---
> v3 <- v2
> - fix highmem build error
>
> v2 <- v1
> - fix highmem code
> ---
> arch/arc/include/asm/pgtable.h | 1 -
> arch/arc/mm/fault.c | 10 ++++++++--
> arch/arc/mm/highmem.c | 4 +++-
> 3 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
> index 976b5931372e..902d45428cea 100644
> --- a/arch/arc/include/asm/pgtable.h
> +++ b/arch/arc/include/asm/pgtable.h
> @@ -33,7 +33,6 @@
> #define _ASM_ARC_PGTABLE_H
>
> #include <linux/bits.h>
> -#define __ARCH_USE_5LEVEL_HACK
> #include <asm-generic/pgtable-nopmd.h>
> #include <asm/page.h>
> #include <asm/mmu.h> /* to propagate CONFIG_ARC_MMU_VER <n> */
> diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
> index 3861543b66a0..fb86bc3e9b35 100644
> --- a/arch/arc/mm/fault.c
> +++ b/arch/arc/mm/fault.c
> @@ -30,6 +30,7 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address)
> * with the 'reference' page table.
> */
> pgd_t *pgd, *pgd_k;
> + p4d_t *p4d, *p4d_k;
> pud_t *pud, *pud_k;
> pmd_t *pmd, *pmd_k;
>
> @@ -39,8 +40,13 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address)
> if (!pgd_present(*pgd_k))
> goto bad_area;
>
> - pud = pud_offset(pgd, address);
> - pud_k = pud_offset(pgd_k, address);
> + p4d = p4d_offset(pgd, address);
> + p4d_k = p4d_offset(pgd_k, address);
> + if (!p4d_present(*p4d_k))
> + goto bad_area;
> +
> + pud = pud_offset(p4d, address);
> + pud_k = pud_offset(p4d_k, address);
> if (!pud_present(*pud_k))
> goto bad_area;
>
> diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
> index a4856bfaedf3..fc8849e4f72e 100644
> --- a/arch/arc/mm/highmem.c
> +++ b/arch/arc/mm/highmem.c
> @@ -111,12 +111,14 @@ EXPORT_SYMBOL(__kunmap_atomic);
> static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
> {
> pgd_t *pgd_k;
> + p4d_t *p4d_k;
> pud_t *pud_k;
> pmd_t *pmd_k;
> pte_t *pte_k;
>
> pgd_k = pgd_offset_k(kvaddr);
> - pud_k = pud_offset(pgd_k, kvaddr);
> + p4d_k = p4d_offset(pgd_k, kvaddr);
> + pud_k = pud_offset(p4d_k, kvaddr);
> pmd_k = pmd_offset(pud_k, kvaddr);
>
> pte_k = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
> --
> 2.20.1
>
>
--
Sincerely yours,
Mike.
