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    Subject[PATCH] x86: fix init_memory_mapping over boundary v2
    Date

    some end boundary is only page alignment, instead of 2M alignment,
    so call ker_phycial_mapping_init three times.
    then don't overmap above the max_low_pfn

    v2: make init_memory_mapping more solid: start could be any value other than 0

    Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

    ---
    arch/x86/mm/init_32.c | 86 ++++++++++++++++++++++++++++++++++++--------------
    1 file changed, 62 insertions(+), 24 deletions(-)

    Index: linux-2.6/arch/x86/mm/init_32.c
    ===================================================================
    --- linux-2.6.orig/arch/x86/mm/init_32.c
    +++ linux-2.6/arch/x86/mm/init_32.c
    @@ -184,8 +184,9 @@ static inline int is_kernel_text(unsigne
    * PAGE_OFFSET:
    */
    static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
    - unsigned long start,
    - unsigned long end)
    + unsigned long start_pfn,
    + unsigned long end_pfn,
    + int use_pse)
    {
    int pgd_idx, pmd_idx, pte_ofs;
    unsigned long pfn;
    @@ -193,32 +194,30 @@ static void __init kernel_physical_mappi
    pmd_t *pmd;
    pte_t *pte;
    unsigned pages_2m = 0, pages_4k = 0;
    - unsigned limit_pfn = end >> PAGE_SHIFT;

    - pgd_idx = pgd_index(PAGE_OFFSET);
    - pgd = pgd_base + pgd_idx;
    - pfn = start >> PAGE_SHIFT;
    + if (!cpu_has_pse)
    + use_pse = 0;

    + pfn = start_pfn;
    + pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
    + pgd = pgd_base + pgd_idx;
    for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
    pmd = one_md_table_init(pgd);
    - if (pfn >= limit_pfn)
    +
    + if (pfn >= end_pfn)
    continue;

    - for (pmd_idx = 0;
    - pmd_idx < PTRS_PER_PMD && pfn < limit_pfn;
    + pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
    + pmd += pmd_idx;
    + for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
    pmd++, pmd_idx++) {
    unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;

    /*
    * Map with big pages if possible, otherwise
    * create normal page tables:
    - *
    - * Don't use a large page for the first 2/4MB of memory
    - * because there are often fixed size MTRRs in there
    - * and overlapping MTRRs into large pages can cause
    - * slowdowns.
    */
    - if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0)) {
    + if (use_pse) {
    unsigned int addr2;
    pgprot_t prot = PAGE_KERNEL_LARGE;

    @@ -233,13 +232,12 @@ static void __init kernel_physical_mappi
    set_pmd(pmd, pfn_pmd(pfn, prot));

    pfn += PTRS_PER_PTE;
    - max_pfn_mapped = pfn;
    continue;
    }
    pte = one_page_table_init(pmd);

    for (pte_ofs = 0;
    - pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
    + pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
    pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
    pgprot_t prot = PAGE_KERNEL;

    @@ -249,7 +247,6 @@ static void __init kernel_physical_mappi
    pages_4k++;
    set_pte(pte, pfn_pte(pfn, prot));
    }
    - max_pfn_mapped = pfn;
    }
    }
    update_page_count(PG_LEVEL_2M, pages_2m);
    @@ -729,7 +726,7 @@ void __init setup_bootmem_allocator(void

    static void __init find_early_table_space(unsigned long end)
    {
    - unsigned long puds, pmds, tables, start;
    + unsigned long puds, pmds, ptes, tables, start;

    puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
    tables = PAGE_ALIGN(puds * sizeof(pud_t));
    @@ -737,10 +734,15 @@ static void __init find_early_table_spac
    pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
    tables += PAGE_ALIGN(pmds * sizeof(pmd_t));

    - if (!cpu_has_pse) {
    - int ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
    - tables += PAGE_ALIGN(ptes * sizeof(pte_t));
    - }
    + if (cpu_has_pse) {
    + int extra;
    + extra = end - ((end>>21) << 21);
    + extra += (2<<20);
    + ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
    + } else
    + ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
    +
    + tables += PAGE_ALIGN(ptes * sizeof(pte_t));

    /*
    * RED-PEN putting page tables only on node 0 could
    @@ -766,6 +768,8 @@ unsigned long __init_refok init_memory_m
    unsigned long end)
    {
    pgd_t *pgd_base = swapper_pg_dir;
    + unsigned long start_pfn, end_pfn;
    + unsigned long big_page_start;

    /*
    * Find space for the kernel direct mapping tables.
    @@ -790,7 +794,41 @@ unsigned long __init_refok init_memory_m
    __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
    }

    - kernel_physical_mapping_init(pgd_base, start, end);
    + /*
    + * Don't use a large page for the first 2/4MB of memory
    + * because there are often fixed size MTRRs in there
    + * and overlapping MTRRs into large pages can cause
    + * slowdowns.
    + */
    + big_page_start = 2UL<<20;
    + if (start < big_page_start) {
    + start_pfn = start >> PAGE_SHIFT;
    + end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
    + } else {
    + /* head is not 2M alignment ? */
    + start_pfn = (start >> 21) << (21 - PAGE_SHIFT);
    + end_pfn = start >> PAGE_SHIFT;
    + }
    + if (start_pfn < end_pfn)
    + kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
    +
    + /* big page range */
    + start_pfn = ((start + ((2UL<<20) - 1)) >> 21) << (21 - PAGE_SHIFT);
    + if (start_pfn < (big_page_start >> PAGE_SHIFT))
    + start_pfn = big_page_start >> PAGE_SHIFT;
    + end_pfn = (end >> 21) << (21 - PAGE_SHIFT);
    + if (start_pfn < end_pfn)
    + kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
    + cpu_has_pse);
    +
    + /* tail is not 2M alignment ? */
    + start_pfn = end_pfn;
    + if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
    + end_pfn = end >> PAGE_SHIFT;
    + if (start_pfn < end_pfn)
    + kernel_physical_mapping_init(pgd_base, start_pfn,
    + end_pfn, 0);
    + }

    early_ioremap_page_table_range_init(pgd_base);


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