| Date: Tue, 7 May 2013 10:14:54 -0600 |
| From: jerry.hoemann@hp.com |
| Subject: x86/mm: account for PGDIR_SIZE alignment |
| |
| Patch for 3.0-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: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| arch/x86/mm/init.c | 5 +++++ |
| 1 file changed, 5 insertions(+) |
| |
| diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c |
| index c22c423..96c4577 100644 |
| --- a/arch/x86/mm/init.c |
| +++ b/arch/x86/mm/init.c |
| @@ -44,11 +44,15 @@ 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; |
| |
| @@ -73,6 +77,7 @@ 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 */ |