From 6af66ec5050bc0a5426192af0429240e8a87e9ca Mon Sep 17 00:00:00 2001 From: "jerry.hoemann@hp.com" Date: Tue, 7 May 2013 10:14:54 -0600 Subject: [PATCH] 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 Signed-off-by: Ben Hutchings --- 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 34a7f4038e9f..a4cca066c889 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 */ -- 2.39.2