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    Subject[PATCH v1 13/30] powerpc/vdso: Move vdso datapage up front
    Date
    Move the vdso datapage in front of the VDSO area,
    before vdso test.

    This will allow to remove the __kernel_datapage_offset symbol
    and simplify __get_datapage() in following patches.

    Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
    ---
    arch/powerpc/include/asm/mmu_context.h | 2 +-
    arch/powerpc/kernel/vdso.c | 14 +++++++-------
    2 files changed, 8 insertions(+), 8 deletions(-)

    diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
    index d54358cb5be1..e5a5e3cb7724 100644
    --- a/arch/powerpc/include/asm/mmu_context.h
    +++ b/arch/powerpc/include/asm/mmu_context.h
    @@ -262,7 +262,7 @@ extern void arch_exit_mmap(struct mm_struct *mm);
    static inline void arch_unmap(struct mm_struct *mm,
    unsigned long start, unsigned long end)
    {
    - unsigned long vdso_base = (unsigned long)mm->context.vdso;
    + unsigned long vdso_base = (unsigned long)mm->context.vdso - PAGE_SIZE;

    if (start <= vdso_base && vdso_base < end)
    mm->context.vdso = NULL;
    diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
    index 87b77b793029..7042e9edfb96 100644
    --- a/arch/powerpc/kernel/vdso.c
    +++ b/arch/powerpc/kernel/vdso.c
    @@ -123,7 +123,7 @@ static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struc
    if (new_size != text_size + PAGE_SIZE)
    return -EINVAL;

    - current->mm->context.vdso = (void __user *)new_vma->vm_start;
    + current->mm->context.vdso = (void __user *)new_vma->vm_start + PAGE_SIZE;

    return 0;
    }
    @@ -198,7 +198,7 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int
    * install_special_mapping or the perf counter mmap tracking code
    * will fail to recognise it as a vDSO.
    */
    - mm->context.vdso = (void __user *)vdso_base;
    + mm->context.vdso = (void __user *)vdso_base + PAGE_SIZE;

    /*
    * our vma flags don't have VM_WRITE so by default, the process isn't
    @@ -510,7 +510,7 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
    return -1;
    }
    *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
    - (vdso64_pages << PAGE_SHIFT) -
    + -PAGE_SIZE -
    (sym64->st_value - VDSO64_LBASE);
    #endif /* CONFIG_PPC64 */

    @@ -522,7 +522,7 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
    return -1;
    }
    *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
    - (vdso32_pages << PAGE_SHIFT) -
    + -PAGE_SIZE -
    (sym32->st_value - VDSO32_LBASE);
    #endif

    @@ -696,10 +696,10 @@ static struct page ** __init vdso_setup_pages(void *start, void *end)
    if (!pagelist)
    panic("%s: Cannot allocate page list for VDSO", __func__);

    - for (i = 0; i < pages; i++)
    - pagelist[i] = virt_to_page(start + i * PAGE_SIZE);
    + pagelist[0] = virt_to_page(vdso_data);

    - pagelist[i] = virt_to_page(vdso_data);
    + for (i = 0; i < pages; i++)
    + pagelist[i + 1] = virt_to_page(start + i * PAGE_SIZE);

    return pagelist;
    }
    --
    2.25.0
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