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    SubjectRe: [PATCH] x86: fix init_memory_mapping over boundary v2
    On Sat, Jun 28, 2008 at 12:47 AM, Ingo Molnar <mingo@elte.hu> wrote:
    >
    > * Yinghai Lu <yhlu.kernel@gmail.com> wrote:
    >
    >> On Sat, Jun 28, 2008 at 12:02 AM, Ingo Molnar <mingo@elte.hu> wrote:
    >> >
    >> > * Ingo Molnar <mingo@elte.hu> wrote:
    >> >
    >> >> * Yinghai Lu <yhlu.kernel@gmail.com> wrote:
    >> >>
    >> >> > 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
    >> >>
    >> >> applied to tip/x86/unify-setup, thanks Yinghai.
    >> >
    >> > -tip testing found a 32-bit spontaneous reboot during bootup, with this
    >> > config:
    >> >
    >> > http://redhat.com/~mingo/misc/config-Sat_Jun_28_08_43_52_CEST_2008.bad
    >> >
    >> > no serial log produced at all.
    >> even with console=uart8250,io,0x03f8,115200n8 ?
    >
    > correct, i use earlyprintk=serial,ttyS0,115200.
    >
    > i just re-tested it - doing "git merge tip/x86/unify-setup" in the
    > tip/master branch triggers the failure with that config on a wide range
    > of 32-bit boxes.

    please check attached v3..., that is less intrusive.

    YH
    [PATCH] x86: fix init_memory_mapping over boundary v3

    some end boundary is only page alignment, instead of 2M alignment,

    v2: make init_memory_mapping more solid: start could be any value other than 0
    v3: fix NON PAE by handling left over in kernel_physical_mapping

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

    ---
    arch/x86/mm/init_32.c | 24 ++++++++++++++----------
    1 file changed, 14 insertions(+), 10 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
    @@ -195,7 +195,7 @@ static void __init kernel_physical_mappi
    unsigned pages_2m = 0, pages_4k = 0;
    unsigned limit_pfn = end >> PAGE_SHIFT;

    - pgd_idx = pgd_index(PAGE_OFFSET);
    + pgd_idx = pgd_index(start + PAGE_OFFSET);
    pgd = pgd_base + pgd_idx;
    pfn = start >> PAGE_SHIFT;

    @@ -218,7 +218,8 @@ static void __init kernel_physical_mappi
    * and overlapping MTRRs into large pages can cause
    * slowdowns.
    */
    - if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0)) {
    + if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0) &&
    + (pfn + PTRS_PER_PTE) <= limit_pfn) {
    unsigned int addr2;
    pgprot_t prot = PAGE_KERNEL_LARGE;

    @@ -233,13 +234,12 @@ 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 < limit_pfn;
    pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
    pgprot_t prot = PAGE_KERNEL;

    @@ -249,7 +249,6 @@ 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 +728,7 @@ 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 +736,15 @@ 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) {
    + unsigned long extra;
    + extra = end - ((end>>21) << 21);
    + extra += (2UL<<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
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      Last update: 2008-06-28 12:33    [W:0.034 / U:152.396 seconds]
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