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x86/mm: account for PGDIR_SIZE alignment

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Patch for -stable.  Function find_early_table_space removed upstream.

Fixes panic in alloc_low_page due to pgt_buf overflow during
init_memory_mapping.

find_early_table_space sizes pgt_buf based upon the size of the
memory being mapped, but it does not take into account the alignment
of the memory.  When the region being mapped spans a 512GB (PGDIR_SIZE)
alignment, a panic from alloc_low_pages occurs.

kernel_physical_mapping_init takes into account PGDIR_SIZE alignment.
This causes an extra call to alloc_low_page to be made.  This extra call
isn't accounted for by find_early_table_space and causes a kernel panic.

Change is to take into account PGDIR_SIZE alignment in find_early_table_space.

Signed-off-by: Jerry Hoemann <jerry.hoemann@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jerry Hoemann 2013-04-30 15:15:55 -06:00 committed by Greg Kroah-Hartman
parent e4727b26cd
commit 94544e2e6e
1 changed files with 5 additions and 0 deletions
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5
arch/x86/mm/init.c
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@ -45,11 +45,15 @@ static void __init find_early_table_space(struct map_range *mr, int nr_range)
int i;
unsigned long puds = 0, pmds = 0, ptes = 0, tables;
unsigned long start = 0, good_end;
unsigned long pgd_extra = 0;
phys_addr_t base;
for (i = 0; i < nr_range; i++) {
unsigned long range, extra;
if ((mr[i].end >> PGDIR_SHIFT) - (mr[i].start >> PGDIR_SHIFT))
pgd_extra++;
range = mr[i].end - mr[i].start;
puds += (range + PUD_SIZE - 1) >> PUD_SHIFT;
@ -74,6 +78,7 @@ static void __init find_early_table_space(struct map_range *mr, int nr_range)
tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
tables += (pgd_extra * PAGE_SIZE);
#ifdef CONFIG_X86_32
/* for fixmap */