Commit 20167d34 authored by Jan Beulich's avatar Jan Beulich Committed by Ingo Molnar
Browse files

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: default avatarJan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4FB3C27202000078000841A0@nat28.tlf.novell.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 3e7f3db0

arch/x86/mm/init_64.c

+13 −10
Original line number Diff line number Diff line
@@ -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;

		}

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