From 20167d3421a089a1bf1bd680b150dc69c9506810 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 16 May 2012 14:06:26 +0100 Subject: [PATCH] x86-64: Fix accounting in kernel_physical_mapping_init() When finding a present and acceptable 2M/1G mapping, the number of pages mapped this way shouldn't be incremented (as it was already incremented when the earlier part of the mapping was established). Instead, last_map_addr needs to be updated in this case. Further, address increments were wrong in one place each in both phys_pmd_init() and phys_pud_init() (lacking the aligning down to the respective page boundary). As we're now doing the same calculation several times, fold it into a single instance using a local variable (matching how kernel_physical_mapping_init() itself does it at the PGD level). Observed during code inspection, not because of an actual problem. Signed-off-by: Jan Beulich Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/4FB3C27202000078000841A0@nat28.tlf.novell.com Signed-off-by: Ingo Molnar --- arch/x86/mm/init_64.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 436a0309db33..f9476a0f8cb6 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -408,12 +408,12 @@ static unsigned long __meminit phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, unsigned long page_size_mask, pgprot_t prot) { - unsigned long pages = 0; + unsigned long pages = 0, next; unsigned long last_map_addr = end; int i = pmd_index(address); - for (; i < PTRS_PER_PMD; i++, address += PMD_SIZE) { + for (; i < PTRS_PER_PMD; i++, address = next) { unsigned long pte_phys; pmd_t *pmd = pmd_page + pmd_index(address); pte_t *pte; @@ -427,6 +427,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, break; } + next = (address & PMD_MASK) + PMD_SIZE; + if (pmd_val(*pmd)) { if (!pmd_large(*pmd)) { spin_lock(&init_mm.page_table_lock); @@ -450,7 +452,7 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, * attributes. */ if (page_size_mask & (1 << PG_LEVEL_2M)) { - pages++; + last_map_addr = next; continue; } new_prot = pte_pgprot(pte_clrhuge(*(pte_t *)pmd)); @@ -463,7 +465,7 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, pfn_pte(address >> PAGE_SHIFT, __pgprot(pgprot_val(prot) | _PAGE_PSE))); spin_unlock(&init_mm.page_table_lock); - last_map_addr = (address & PMD_MASK) + PMD_SIZE; + last_map_addr = next; continue; } @@ -483,11 +485,11 @@ static unsigned long __meminit phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end, unsigned long page_size_mask) { - unsigned long pages = 0; + unsigned long pages = 0, next; unsigned long last_map_addr = end; int i = pud_index(addr); - for (; i < PTRS_PER_PUD; i++, addr = (addr & PUD_MASK) + PUD_SIZE) { + for (; i < PTRS_PER_PUD; i++, addr = next) { unsigned long pmd_phys; pud_t *pud = pud_page + pud_index(addr); pmd_t *pmd; @@ -496,8 +498,9 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end, if (addr >= end) break; - if (!after_bootmem && - !e820_any_mapped(addr, addr+PUD_SIZE, 0)) { + next = (addr & PUD_MASK) + PUD_SIZE; + + if (!after_bootmem && !e820_any_mapped(addr, next, 0)) { set_pud(pud, __pud(0)); continue; } @@ -524,7 +527,7 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end, * attributes. */ if (page_size_mask & (1 << PG_LEVEL_1G)) { - pages++; + last_map_addr = next; continue; } prot = pte_pgprot(pte_clrhuge(*(pte_t *)pud)); @@ -536,7 +539,7 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end, set_pte((pte_t *)pud, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE)); spin_unlock(&init_mm.page_table_lock); - last_map_addr = (addr & PUD_MASK) + PUD_SIZE; + last_map_addr = next; continue; } -- 2.20.1