On Sat, Oct 06, 2012 at 12:44:28AM -0700, Yinghai Lu wrote:
> During adding code from BRK to map buffer for final page table,
>
> It should be safe to remove early_memmap for page table accessing.
>
> But get panic after that.
>
> It turns out we clear the initial page table wrongly for next range
> that is separated by holes.
Were are the holes? Are these E820 holes?
> And it only happens when we are trying to map range one by one range.
>
> After checking before clearing the related page table to fix the problem.
Huh?
>
> Signed-off-by: Yinghai Lu <ying...@kernel.org>
> ---
> arch/x86/mm/init_64.c | 39 +++++++++++++++++++--------------------
> 1 files changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 5375cf0..0348a02 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -367,20 +367,21 @@ static unsigned long __meminit
> phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end,
> pgprot_t prot)
> {
> - unsigned pages = 0;
> + unsigned long pages = 0, next;
> unsigned long last_map_addr = end;
> int i;
>
> pte_t *pte = pte_page + pte_index(addr);
>
> - for(i = pte_index(addr); i < PTRS_PER_PTE; i++, addr += PAGE_SIZE,
> pte++) {
> + for (i = pte_index(addr); i < PTRS_PER_PTE; i++, addr = next, pte++) {
>
> + next = (addr & PAGE_MASK) + PAGE_SIZE;
> if (addr >= end) {
> - if (!after_bootmem) {
> - for(; i < PTRS_PER_PTE; i++, pte++)
> - set_pte(pte, __pte(0));
> - }
> - break;
> + if (!after_bootmem &&
> + addr < (2UL<<30) &&
Why 2G?
> + !e820_any_mapped(addr & PAGE_MASK, next, 0))
What is the 0 parameter for?
> + set_pte(pte, __pte(0));
> + continue;
> }
>
> /*
> @@ -422,16 +423,15 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address,
> unsigned long end,
> pte_t *pte;
> pgprot_t new_prot = prot;
>
> + next = (address & PMD_MASK) + PMD_SIZE;
> if (address >= end) {
> - if (!after_bootmem) {
> - for (; i < PTRS_PER_PMD; i++, pmd++)
> - set_pmd(pmd, __pmd(0));
> - }
> - break;
> + if (!after_bootmem &&
> + address < (2UL<<30) &&
> + !e820_any_mapped(address & PMD_MASK, next, 0))
> + set_pmd(pmd, __pmd(0));
> + continue;
> }
>
> - next = (address & PMD_MASK) + PMD_SIZE;
> -
> if (pmd_val(*pmd)) {
> if (!pmd_large(*pmd)) {
> spin_lock(&init_mm.page_table_lock);
> @@ -498,13 +498,12 @@ phys_pud_init(pud_t *pud_page, unsigned long addr,
> unsigned long end,
> pmd_t *pmd;
> pgprot_t prot = PAGE_KERNEL;
>
> - if (addr >= end)
> - break;
Why do you get rid of that?
> -
> next = (addr & PUD_MASK) + PUD_SIZE;
> -
> - if (!after_bootmem && !e820_any_mapped(addr, next, 0)) {
> - set_pud(pud, __pud(0));
> + if (addr >= end) {
> + if (!after_bootmem &&
> + addr < (2UL<<30) &&
> + !e820_any_mapped(addr & PUD_MASK, next, 0))
> + set_pud(pud, __pud(0));
> continue;
> }
>
> --
> 1.7.7
>
> --
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