>>> On 20.11.12 at 16:04, Daniel Kiper <daniel.kiper at oracle.com> wrote:
> Some implementations (e.g. Xen PVOPS) could not use part of identity page
> table
> to construct transition page table. It means that they require separate
> PUDs,
> PMDs and PTEs for virtual and physical (identity) mapping. To satisfy that
> requirement add extra pointer to PGD, PUD, PMD and PTE and align existing
> code.
As said for v1 already - this is not really a requirement of the
interface, or else none of our Xen kernels since 2.6.30 would
have worked. I don't think it is desirable to introduce overhead
for everyone if it's not even needed for Xen.
Jan
> Signed-off-by: Daniel Kiper <daniel.kiper at oracle.com>
> ---
> arch/x86/include/asm/kexec.h | 10 +++++++---
> arch/x86/kernel/machine_kexec_64.c | 12 ++++++------
> 2 files changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 317ff17..3cf5600 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -157,9 +157,13 @@ struct kimage_arch {
> };
> #else
> struct kimage_arch {
> - pud_t *pud;
> - pmd_t *pmd;
> - pte_t *pte;
> + pgd_t *pgd;
> + pud_t *pud0;
> + pud_t *pud1;
> + pmd_t *pmd0;
> + pmd_t *pmd1;
> + pte_t *pte0;
> + pte_t *pte1;
> };
> #endif
>
> diff --git a/arch/x86/kernel/machine_kexec_64.c
> b/arch/x86/kernel/machine_kexec_64.c
> index b3ea9db..976e54b 100644
> --- a/arch/x86/kernel/machine_kexec_64.c
> +++ b/arch/x86/kernel/machine_kexec_64.c
> @@ -137,9 +137,9 @@ out:
>
> static void free_transition_pgtable(struct kimage *image)
> {
> - free_page((unsigned long)image->arch.pud);
> - free_page((unsigned long)image->arch.pmd);
> - free_page((unsigned long)image->arch.pte);
> + free_page((unsigned long)image->arch.pud0);
> + free_page((unsigned long)image->arch.pmd0);
> + free_page((unsigned long)image->arch.pte0);
> }
>
> static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
> @@ -157,7 +157,7 @@ static int init_transition_pgtable(struct kimage *image,
> pgd_t *pgd)
> pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
> if (!pud)
> goto err;
> - image->arch.pud = pud;
> + image->arch.pud0 = pud;
> set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
> }
> pud = pud_offset(pgd, vaddr);
> @@ -165,7 +165,7 @@ static int init_transition_pgtable(struct kimage *image,
> pgd_t *pgd)
> pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
> if (!pmd)
> goto err;
> - image->arch.pmd = pmd;
> + image->arch.pmd0 = pmd;
> set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
> }
> pmd = pmd_offset(pud, vaddr);
> @@ -173,7 +173,7 @@ static int init_transition_pgtable(struct kimage *image,
> pgd_t *pgd)
> pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
> if (!pte)
> goto err;
> - image->arch.pte = pte;
> + image->arch.pte0 = pte;
> set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
> }
> pte = pte_offset_kernel(pmd, vaddr);
> --
> 1.5.6.5
