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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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