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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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