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SubjectRe: [PATCH 22/46] x86, mm: Remove early_memremap workaround for page table accessing on 64bit
On Mon, 12 Nov 2012, Yinghai Lu wrote:
> We try to put page table high to make room for kdump, and at that time
> those ranges are not mapped yet, and have to use ioremap to access it.
>
> Now after patch that pre-map page table top down.
> x86, mm: setup page table in top-down
> We do not need that workaround anymore.
>
> Just use __va to return directly mapping address.
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>


Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

> arch/x86/mm/init_64.c | 38 ++++----------------------------------
> 1 files changed, 4 insertions(+), 34 deletions(-)
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index eefaea6..5ee9242 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -340,36 +340,12 @@ static __ref void *alloc_low_page(unsigned long *phys)
> } else
> pfn = pgt_buf_end++;
>
> - adr = early_memremap(pfn * PAGE_SIZE, PAGE_SIZE);
> + adr = __va(pfn * PAGE_SIZE);
> clear_page(adr);
> *phys = pfn * PAGE_SIZE;
> return adr;
> }
>
> -static __ref void *map_low_page(void *virt)
> -{
> - void *adr;
> - unsigned long phys, left;
> -
> - if (after_bootmem)
> - return virt;
> -
> - phys = __pa(virt);
> - left = phys & (PAGE_SIZE - 1);
> - adr = early_memremap(phys & PAGE_MASK, PAGE_SIZE);
> - adr = (void *)(((unsigned long)adr) | left);
> -
> - return adr;
> -}
> -
> -static __ref void unmap_low_page(void *adr)
> -{
> - if (after_bootmem)
> - return;
> -
> - early_iounmap((void *)((unsigned long)adr & PAGE_MASK), PAGE_SIZE);
> -}
> -
> static unsigned long __meminit
> phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end,
> pgprot_t prot)
> @@ -442,10 +418,9 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
> if (pmd_val(*pmd)) {
> if (!pmd_large(*pmd)) {
> spin_lock(&init_mm.page_table_lock);
> - pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd));
> + pte = (pte_t *)pmd_page_vaddr(*pmd);
> last_map_addr = phys_pte_init(pte, address,
> end, prot);
> - unmap_low_page(pte);
> spin_unlock(&init_mm.page_table_lock);
> continue;
> }
> @@ -483,7 +458,6 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
>
> pte = alloc_low_page(&pte_phys);
> last_map_addr = phys_pte_init(pte, address, end, new_prot);
> - unmap_low_page(pte);
>
> spin_lock(&init_mm.page_table_lock);
> pmd_populate_kernel(&init_mm, pmd, __va(pte_phys));
> @@ -518,10 +492,9 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
>
> if (pud_val(*pud)) {
> if (!pud_large(*pud)) {
> - pmd = map_low_page(pmd_offset(pud, 0));
> + pmd = pmd_offset(pud, 0);
> last_map_addr = phys_pmd_init(pmd, addr, end,
> page_size_mask, prot);
> - unmap_low_page(pmd);
> __flush_tlb_all();
> continue;
> }
> @@ -560,7 +533,6 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
> pmd = alloc_low_page(&pmd_phys);
> last_map_addr = phys_pmd_init(pmd, addr, end, page_size_mask,
> prot);
> - unmap_low_page(pmd);
>
> spin_lock(&init_mm.page_table_lock);
> pud_populate(&init_mm, pud, __va(pmd_phys));
> @@ -596,17 +568,15 @@ kernel_physical_mapping_init(unsigned long start,
> next = end;
>
> if (pgd_val(*pgd)) {
> - pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd));
> + pud = (pud_t *)pgd_page_vaddr(*pgd);
> last_map_addr = phys_pud_init(pud, __pa(start),
> __pa(end), page_size_mask);
> - unmap_low_page(pud);
> continue;
> }
>
> pud = alloc_low_page(&pud_phys);
> last_map_addr = phys_pud_init(pud, __pa(start), __pa(next),
> page_size_mask);
> - unmap_low_page(pud);
>
> spin_lock(&init_mm.page_table_lock);
> pgd_populate(&init_mm, pgd, __va(pud_phys));
> --
> 1.7.7
>


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