[PATCH] arm64: Add support for 4level 4K page translations table
Pratyush Anand
panand at redhat.com
Tue Jan 5 22:56:47 PST 2016
Hi Azriel,
Thanks for working on 4 level 4K page support.
On 05/01/2016:05:12:39 PM, Azriel Samson wrote:
> Add PUD translation for 4 level page tables.
>
> Signed-off-by: Mansi Patel <mansip at codeaurora.org>
> Signed-off-by: Azriel Samson <asamson at codeaurora.org>
> ---
> This change targets the arm64_support branch of Pratush Anand's repository at:
> https://github.com/pratyushanand/makedumpfile.git
>
> arch/arm64.c | 25 ++++++++++++++++++-------
> 1 file changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64.c b/arch/arm64.c
> index 59825fa..62c76e3 100644
> --- a/arch/arm64.c
> +++ b/arch/arm64.c
> @@ -35,15 +35,10 @@ typedef struct {
> pud_t pud;
> } pmd_t;
>
> -#define pud_offset(pgd, vaddr) ((pud_t *)pgd)
> -
> #define pgd_val(x) ((x).pgd)
> #define pud_val(x) (pgd_val((x).pgd))
> #define pmd_val(x) (pud_val((x).pud))
>
> -#define PUD_SHIFT PGDIR_SHIFT
> -#define PUD_SIZE (1UL << PUD_SHIFT)
> -
> typedef struct {
> unsigned long pte;
> } pte_t;
> @@ -59,6 +54,10 @@ typedef struct {
> #define PMD_SIZE (1UL << PMD_SHIFT)
> #define PMD_MASK (~(PMD_SIZE - 1))
> #define PTRS_PER_PMD PTRS_PER_PTE
> +#define PUD_SHIFT ((PAGE_SHIFT - 3) * 3 + 3)
It will break system with pgtable_level <= 3. I think it would be better to keep
it like as follows:
static int
get_pud_shift_arm64(void)
{
if (pgtable_level == 4)
return ((PAGE_SHIFT - 3) * 3 + 3);
else
return PGDIR_SHIFT;
}
#define PUD_SHIFT get_pud_shift_arm64()
> +#define PUD_SIZE (1UL << PUD_SHIFT)
> +#define PUD_MASK (~(PUD_SIZE - 1))
> +#define PTRS_PER_PUD PTRS_PER_PTE
>
> #define PAGE_PRESENT (1 << 0)
> #define SECTIONS_SIZE_BITS 30
> @@ -95,6 +94,10 @@ typedef struct {
> #define pud_page_vaddr(pud) (__va(pud_val(pud) & PHYS_MASK & (int32_t)PAGE_MASK))
> #define pmd_offset_pgtbl_lvl_3(pud, vaddr) ((pmd_t *)pud_page_vaddr((*pud)) + pmd_index(vaddr))
>
Since above definition for PTRS_PER_PUD is true only for 4 level page table so
better to keep that define here.
> +#define pud_index(vaddr) (((vaddr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
> +#define pgd_page_vaddr(pgd) (__va(pgd_val(pgd) & PHYS_MASK & (int32_t)PAGE_MASK))
> +#define pud_offset(pgd, vaddr) ((pud_t *)pgd_page_vaddr((*pgd)) + pud_index(vaddr))
> +
May be following would be better:
static pud_t *
pud_offset(pgd_t *pgd, unsigned long vaddr)
{
if (pgtable_level == 4)
return ((pud_t *)pgd_page_vaddr((*pgd)) + pud_index(vaddr));
else
return (pud_t *)pgd;
}
> /* kernel struct page size can be kernel version dependent, currently
> * keep it constant.
> */
> @@ -244,7 +247,7 @@ vtop_arm64(unsigned long vaddr)
> {
> unsigned long long paddr = NOT_PADDR;
> pgd_t *pgda, pgdv;
> - pud_t pudv;
> + pud_t *puda, pudv;
> pmd_t *pmda, pmdv;
> pte_t *ptea, ptev;
>
> @@ -259,7 +262,15 @@ vtop_arm64(unsigned long vaddr)
> return NOT_PADDR;
> }
>
> - pudv.pgd = pgdv;
> + if (pgtable_level <= 3) {
> + pudv.pgd = pgdv;
> + } else {
With suggested pud_offset() definition, we can get rid of above "if" condition and
then pud calculation code would be in sync with other calculations like that of
pgd and pmd.
> + puda = pud_offset(&pgdv, vaddr);
> + if (!readmem(VADDR, (unsigned long long)puda, &pudv, sizeof(pudv))) {
> + ERRMSG("Can't read pud\n");
> + return NOT_PADDR;
> + }
> + }
~Pratyush
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